University of California Berkeley 
 
 SIDNEY HOWARD COLLECTION 
 
 Gift of 
 The Family of Sidney Howard 
 
 SIDNEY 
 
 HOW/ 
 
PREFACE. 
 
 The results of the work of Maj. Walter Reed, Medical Corps, 
 United States Army, and the Yellow Fever Commission, of which he 
 was president and the masterful mind, have been so beneficial and 
 far-reaching that its importance is considered secondary to no other 
 scientific achievement. 
 
 The various publications in regard to Maj. Reed and his work and 
 the reports of the commission, as well as other reports on subjects 
 intimately connected with this work, while all extant and on file in 
 the larger libraries of this country, are not available for the profes- 
 sion in general. Being bound in one volume they will be much more 
 available for general use, and will be less liable to be misplaced. 
 
 Many of the younger men in the profession and in the Medical 
 Corps of the Army are not so thoroughly conversant with the various 
 steps of this work as is thought desirable. This work should be a 
 source of inspiration for every medical officer. 
 
 In compiling these various publications repetitions have been 
 avoided as much as possible. However, the reports of Maj. Reed 
 and his associates are considered of so much scientific as well as his- 
 torical interest that they are published in full in chronological order. 
 In this way the various steps in the experiments are more clearly 
 shown. 
 
 3 
 
I 
 
TABLE OF CONTENTS. 
 
 Page. 
 
 PART I. Walter Reed, the man, his work, and the appreciation shown of the 
 results accomplished by him and his associates on the Yellow Fever Commis- 
 sion: 
 
 Chapter 1. A memoir 7 
 
 Chapter 2. Sketch of the life of Maj. Walter Reed 14 
 
 Chapter 3. Message from the President of the United States, December 5, 
 1906, embodying letter from Brig. Gen. R. M. O'Reilly, Surgeon General 
 
 United States Army 17 
 
 Chapter 4. Senate Document No. 520, Sixty-first Congress, second session, 
 embodying letter from Brig. Gen. George H. Torney, Surgeon General 
 
 United States Army 24 
 
 Chapter 5. In memoriam; District of Columbia Medical Society 32 
 
 Chapter 6. Value of Dr. Reed's work and expressions of appreciation 48 
 
 PART II. The publications of Walter Reed and his associates on the commis- 
 sion in regard to yellow fever: 
 Chapter 1. Bacillus icteroides and Bacillus cholenv suis A preliminary note, 
 
 April 1, 1899 53 
 
 Chapter 2. The Etiology of Yellow Fever A preliminary note, October, 
 
 1900 56 
 
 Chapter 3. The Etiology of Yellow Fever An additional note, February, 
 
 1901 70 
 
 Chapter 4. The Propagation of Yellow Fever Observations based on recent 
 
 researches, April, 1901 90 
 
 Chapter 5. Experimental Yellow Fever, May, 1901 110 
 
 Chapter 6. The Prevention of Yellow Fever, September, 1901 131 
 
 Chapter 7. The Etiology of Yellow Fever A supplemental note, January, 
 
 1902 149 
 
 Chapter 8. Recent Researches Concerning the Etiology, Propagation, and 
 Prevention of Yellow Fever, by The United States Army Commission 
 
 (three charts), April, 1902 161 
 
 PART III. The publications of James Carroll, assistant surgeon, United States 
 Army, in regard to yellow fever (published after the death of Maj. Reed): 
 
 Chapter 1. The Transmission of Yellow Fever, May, 1903 175 
 
 Chapter 2. Remarks on the Epidemic of Yellow Fever in Baltimore, Feb- 
 ruary, 1905 186 
 
 Chapter 3. Yellow Fever A popular lecture, April, 1905 195 
 
 Chapter 4. Lessons to be Learned from the Present Outbreak of Yellow 
 
 Fever in Louisiana, September, 1905 216 
 
 PART IV. Reports from sanitary officers in Habana, Cuba, demonstrating the 
 practical value of the scientific findings of Maj. Reed and his associates on the 
 Yellow Fever Commission: 
 
 Chapter 1. Report of Col. Valery Havard, February, 1901 221 
 
 Chapter 2. Report of Charles Finlay, chairman of the Habana Yellow Fever 
 
 Commission, January, 1902 227 
 
 Chapter3. Report of Maj. W. C. Gorgas, Medical Corps, United States 
 
 Army, July, 1902 234 
 
 PART V. A few general directions with regard to destroying mosquitoes, par- 
 ticularly the yellow-fever mosquito, by Col. William C. Gorgas, Medical 
 
 Corps, United States Army 
 
 5 
 
 I 
 
 
PART I WALTER REED THE MAN, HIS WORK, AND THE APPRECIA- 
 TION SHOWN OF THE RESULTS ACCOMPLISHED BY HIM AND HIS 
 ASSOCIATES ON THE YELLOW FEVER COMMISSION, 
 
 CHAPTER 1. 
 
 WALTER REED. A MEMOIR. 1 
 
 By WALTER D. MCAW, Major, Medical Corps, United States Army. 
 
 It is given to but few scientific men to lay bare a secret of nature 
 materially affecting the prosperity of nations, and the lives, fortunes, 
 and happiness of thousands. Fewer still succeed in so quickly con- 
 vincing brother scientists and men in authority of the truth of their 
 discoveries that their own eyes behold the glorious result of their 
 labor. 
 
 Of the 51 years of Walter Reed's industrious, blameless life, 12 
 only were spent in the study of the special branch of science in which 
 he became famous, but his name now stands with those of Jenner, 
 Lister, and Morton as among the benefactors of humanity. 
 
 Walter Reed was born in Gloucester County, Va., September 13, 
 1851, the son of the Rev. Lemuel Sutton Reed and Pharaba White, 
 his wife. 
 
 The circumstances of his family were modest, and some of the 
 years of his boyhood were spent in a much troubled section of the 
 south during the great Civil War. He acquired, however, a good 
 preliminary education, and at an age when most boys are still in 
 the schoolroom he began the study of medicine at the University of 
 Virginia, graduating as M. D. in 1869, when only 17 years old. 
 
 A second medical degree was received later from Bellevue Medical 
 College, New York, and then came terms of service in the Brooklyn 
 City Hospital, and the City Hospital, BlackwelFs Island. 
 
 Before the age of 21 Reed was a district physician in New York 
 City, and at 22 one of the five inspectors of the board of health of 
 Brooklyn. 
 
 He entered the Army of the United States as assistant surgeon 
 with the rank of first lieutenant, in 1875, and for the next 18 years, 
 with the usual varying fortunes of a young medical officer of the 
 Army, he served in Arizona, Nebraska, Dakota, and in the Southern 
 and Eastern States. 
 
 According to the exigencies of the service he was moved frequently 
 from station to station, everywhere recognized by men of his own 
 age as a charming and sympathetic companion, and by older officers 
 
 1 Washington, D. C. Published by the Walter Reed Memorial Association, 1904. 
 
 7 
 
 
as an earnest and intelligent physician, whose industry, fidelity to 
 duty, and siniri:. U judgment, gave brilliant promise for' the 
 
 future. In the pom cabins and dugouts of the pioneers in the 
 sparsely settled districts where he served his flag, Reed was ev 
 messenger of healing and comfort. At that time Army posts on the 
 frontier were usually remote and with small irnrrisons. The vounir 
 medical oihcer, generally the only one at the station, was called upon 
 bythesr -r mitos around. \Vithout help, and with only such 
 
 instruments and medicines as could be hastily stuffed in his saddle 
 he was summoned to attend a fractured thirh, a child choking \\ith 
 diphtheria, or, most mint: of all, a complicated childhirth. 
 
 Such experience BCOOOb \\ell in self-reliance, and in the formation 
 of quick and accurate observation. 
 
 For a man like Reed, already an earnest student, no better p 
 tion could perhaps have been had. His earlier Army must 
 
 have singularly tended to develop in him the very (pialities i 
 necessary to his final success. To the end of his life il \\. -able 
 
 that even when he had long given up the practice of medicine for the 
 work of the laboratory, he was nevertheless unexcelled at t he bedside 
 for rapid, unerring diagnosis and sound iii<lunent in treatment. 
 also were the series of experiments which robbed yellow fever of its 
 terrors especially remarkable for simplicity, accuracy, and complete- 
 ness, or they never would have so quicldy convinced the won 
 their truth. Too much reverence for accepted teachings, am: 
 little experience in grappling with difficulties unassisted, and they 
 might never have been conceived or carried out. 
 
 In 1890 he was assigned to duty in Baltimore and remained t 
 over a year. Here he had the great advantage of working in the 
 laboratories of Johns Hopkins University and the happiness of win- 
 ning the close friendship of his distinguished teacher, JProf. William 
 II. Welch. 
 
 In 1893, Reed was promoted surgeon with the rank of major. 
 and in the same year was detailed in Washington as curator of the 
 Army Medical Museum and professor of bacteriology at the newly 
 organized Army Medical School. Here he worked industrious) 
 his specialty and wrote many valuable monographs, all ch. 
 terized by accuracy and originality. His excellent judgment made 
 him especially valuable in investigating the causes of epidemic dis- 
 eases at military posts, and in making sanitary inspections. He 
 was, therefore, frequently selected for such work, which with his 
 duties as teacher and member of examining boards, occupied much 
 of the time that he would otherwise have spent in his la! 
 1 i i e again it seems that duties which must often have 1 lome 
 
 were specially fitting him for his culminating work. 
 
 During the Spanish-American war the camps of the volunteer 
 troops in the United States were devastated by typhoid f< 
 Mai. Reed was selected as the head of a board to study the causat ion 
 and spread of the disease. This immense task occupied more than 
 a year's time. With the utmost patience and accuracy the details 
 of hundreds of individual cases were grouped and studied. The 
 report of the commi ion. now in course of publication by the < 
 eminent, is a monumental work which must always serve as a basis 
 for future study of the epidemiology of typhoid fever. 
 
YELLOW FEVER. 9 
 
 The most original and valuable work of the board is the proof 
 that the infection of typhoid fever is spread in camps by the com- 
 mon fly, and by contact with patients and infected articles, clothing, 
 tentage, and utensils, as well as by contaminated drinking water. 
 
 In June, 1900, Maj. Reed was sent to Cuba as president .of a board 
 to study the infectious diseases of the country, but more especially 
 yellow fever. Associated with him were Acting Asst. Surgs. James 
 Carroll, Jesse W. Lazear, and A. Agramonte. 
 
 At this time the American authorities in Cuba had for a year and 
 a half endeavored to diminish the disease and mortality of the Cuban 
 towns, by general sanitary work, but while the health of the popu- 
 lation showed distinct improvement and the mortality had greatly 
 diminished, yellow fever apparently had been entirely unaffected by 
 these measures. In fact, owing to the large number of nonimmune 
 foreigners, the disease was more frequent than usual in Habana and 
 in Quemados near the camp of American troops, and many valuable 
 lives of American officers and soldiers had been lost. 
 
 Reed was convinced from the first that general sanitary measures 
 alone would not check the disease but that its transmission was prob- 
 ably due to an insect. 
 
 The fact that malarial fever, caused by an animal parasite in the 
 blood, is transmitted from man to man through the agency of certain 
 mosquitoes had been recently accepted by the scientific world; also 
 several years before Dr. Carlos Finlay, of Habana, had advanced the 
 theory that a mosquito conveyed the unknown cause of yellow fever, 
 but did not succeed in demonstrating the truth of his theory. 
 
 Dr. H. R. Carter, of the Marine-Hospital Service, had written a 
 paper showing that although the period of incubation of yellow fever 
 was only 5 days, yet a house to which a patient was carried did 
 not become infected for from 15 to 20 days. 
 
 To Reed's mind this indicated that the unknown infective agent 
 has to undergo a period of incubation of from 10 to 15 days, and 
 probably in the body of a biting insect. 
 
 Up to this time the most generally accepted theory as to the causa- 
 tion of yellow fever was that of Sanarelli, who claimed that the 
 Bacillus icier oides discovered by him was the specific agent of the 
 disease. Maj. Reed in association with Dr. Carroll had, however, 
 already demonstrated that this bacillus was one widely disseminated 
 in the United States, and bore no special relation to yellow fever. 
 
 In June, July, and August, 1900, the commission gave their entire 
 attention to the bacteriological study of the blood of yellow-fever 
 patients and the post-mortem examinations of the organs of those 
 dying with the disease. In 24 cases where the blood was repeatedly 
 examined, as well as in 11 carefully studied autopsies, Bacillus 
 icteroides was not discovered, nor was there any indication of the 
 presence in the blood of a specific cause of the disease. 
 
 Application was made to Gen. Leonard Wood, the military governor 
 of Cuba, for permission to conduct experiments on nonimmune 
 persons, and a liberal sum of money requested for the purpose of 
 rewarding volunteers who would submit themselves to experiment. 
 
 It was indeed fortunate that the military governor of Cuba was a 
 man who by his breadth of mind and special scientific training could 
 readily appreciate the arguments of Maj. Reed as to the value of the 
 proposed work. 
 
10 YHLLOW --KVLK. 
 
 Money and full authority to proceed were promptly granted, and to 
 the everlasting L- toe American soldier, volunteers from the 
 
 Army offered themselves for experiment in plenty and with the utmost 
 fearlessness. 
 
 Before the arrangements were entirel\ completed. I>r. Carroll, a 
 member of thecomm Slowed himself to be bitten bv a mosquito 
 
 that 12 days previously had filled it-elf with the blood ofayellow- 
 
 : patient, He -utleivd from a \ er\ < k. and In- was 
 
 the first expenn .-. I >r. La/car al-o experiincnied on him-elf 
 
 at the same time, but was not infected. Some days later, while in 
 the yellow-fever ward, he was bitten by a mosquito and noted the 
 quired the disease in its most terrible form and 
 died a martyr to -nence and a true hen.. 
 
 No other fatality occurred among the brave men who. in the cour-e 
 of the experiments, willingly exposed themselves to the infection of 
 ireaded di-ease. 
 
 A camp was especially constructed for the experiments about 1 
 miles from Habana, christened Camp La/ear in honor of the dead 
 comrade. The inmate- of the camp were put into mo-t ri^id quar- 
 antine and ample time was allowed to eliminate any possibility of 
 the disease being brought in from Habana. 
 
 The personnel consisted of three nurses and nine noniminnnes. all 
 in the military service, and included two physicians. 
 
 From time to time Spanish immigrant >. newly arrived, 
 brought in directly from tne immigrant station: a pW-on not ki 
 to be immune was not allowed to leave camp, or if he did was for- 
 bidden to return. 
 
 The most complete record was kept of the health of every man to 
 be experimented upon, thus eliminating the possibility of any other 
 disease than yellow fever complicating the case. 
 
 The mosquitoes used were specially bred from the eggs and kept 
 hi a building screened by wire netting. When an in nted 
 
 for an experiment it was taken into a yellow fever hospital and 
 allowed to fill it-elf with the blood of a patient; afterwards at varying 
 intervals from the time of this meal of blood it was purposely applied 
 to nonimmunes in camp. 
 
 In December,5 cases of the disease were developed as the re-nl 
 such applications; in January, 3, and in February. J. making in all 
 10, exclusive of the cases of Drs. Carroll and La/ear. Immediately 
 upon the appearance of the first recognized symptoms <>f the disease, 
 in any one of these experimental cases, the patient was taken fn>m 
 Camp Lazear to a vellow-f ever hospital, 1 miledi-iant. I 
 in camp was rigidly protected from accidental mosquit and 
 
 not in a single instance did yellow fever develop in the camp 
 at the will of the experimenters. 
 
 The experiments were conducted at a season when there was the 
 least chance of naturally acquiring the disease, and the mosquitoes 
 used were kept active by* maintaining them at a summer temperature. 
 
 A completely mosquito-proof building was divided into two com- 
 partments by a wire-screen partition; infected insects \\eie liberated 
 on one side only. A brave nonimmune entered and remained 
 enough to allow himself to be bitten several times. He was attacked 
 
 I yellow fever, while two susceptible men in the other ei.nipartment 
 not acquire the disease, ulthou-h deeping there 13 nights. This 
 
YELLOW PEVEK. 11 
 
 demonstrates in the simplest and most certain manner that the infeo- 
 tiousness of the building was due only to the presence of the insects. 
 
 Every attempt was made to infect individuals by means of bedding, 
 clothes, and other articles that had been used and soiled by patients 
 suffering with virulent yellow fever. 
 
 Volunteers slept in the room with and handled the most filthy 
 articles for 20 nights, but not a symptom of yellow fever was noted 
 among them, nor was their health in the slightest degree affected. 
 Nevertheless they were not immune to the disease, for some of them 
 were afterwards purposely infected by mosquito bites. This experi- 
 ment indicates at once the uselessness of destroying valuable property 
 for fear of infection. Had the people of the United States known 
 this one fact 100 hundred years ago, an enormous amount of money 
 would have been saved to householders. 
 
 Besides the experimental cases caused by mosquito bite, four non- 
 immunes were infected by injecting blood drawn directly from the 
 veins of yellow-fever patients in the first two days of the disease, 
 thus demonstrating the presence of an infectious agent in the blood at 
 this early period of the attack. 
 
 Even the blood serum of a patient, passed through a bacteria-proof 
 filter, was found to be capable of causing yellow fever in another 
 person. 
 
 The details of the experiments are most interesting, but it must 
 here suffice to briefly sum up the principal conclusions of this admirable 
 board of investigators of which Reed was the master mind: 
 
 1. The specific agent in the causation of yellow fever exists in the 
 blood of a patient for the first three days of his attack, after which 
 time he ceases to be a menace to the health of others. 
 
 2. A mosquito of a single species, Sjejg^jnjYJafa^cjat^, ingesting the 
 blood of a patient during this infectiveperioaTs powerless to convey 
 the disease to another person by its bite until about 12 days have 
 elapsed, but can do so thereafter for an indefinite period, probably 
 during the remainder of its life. 
 
 3. The disease can not in nature be spread in any other way than 
 by the bite of the previously infected Stegomyia. Articles used and 
 soiled by patients do not carry infection. 
 
 These conclusions pointed so clearly to the practical method ' of 
 exterminating the disease that they were at once accepted by the 
 sanitary authorities in Cuba, and put to the test in Habana, where 
 for nearly a century and a half, by actual record, the disease had 
 never failed to appear annually. 
 
 In February, 1901, the chief sanitary officer in Habana, Maj. W. C. 
 Gorgas, Medical Department, United States Army, instituted meas- 
 ures to eradicate the disease, based entirely on the conclusions of the 
 commission. Cases of yellow fever were required to be reported as 
 promptly as possible, the patient was at first rigidly isolated, and 
 immediately upon the report a force of men from the sanitary depart- 
 ment visited the house. All the rooms of the building and or the 
 neighboring houses were sealed and fumigated to destroy the mos- 
 quitoes present. Window and door screens were put up, and after 
 the death or recovery of the patient, his room was fumigated and 
 every mosquito destroyed. A war of extermination was also waged 
 against mosquitoes in general, and an energetic effort was made to 
 diminish the number bred by draining standing water, screening tanks 
 
12 YELLOW FEVBB. 
 
 and vessels, using petroleum on water that could not he drained, anil 
 in the most systematic manner destroying the breeding place- of the 
 insects. 
 
 When the warm season returned a few cases oc< -ured. hut 1>\ Sep- 
 tember, 1901 , the last case of yellow fever originated in Habana. since 
 which time tin i -it v has been entirely exempt from the terrihle dis- 
 ease, that had there kept stronghold for 150 years. Cases are now 
 admitted into Haba an ports, but are mated under 
 
 screens with perfect impunity, in the ordinary city hospitals. The 
 .ide against the insects also caused a very large decrease in mala- 
 rial fevers. 
 
 The destruction of the most fatal epidemic disease of the Western 
 Hemisphere, in its favorite home city is hut the he-inning of the 
 benefit to mankind that may he expected to follow the work of ! 
 and his associates. There can be no manner of d <m ht should Mexico, 
 Brazil, and the Central American Republics, where the disease still 
 exists, follow strictly the example set by Habana, that yellow fever 
 will become extinct and the I nited States forever freed fnm the 
 scourge that has in the past slain thousands of our citi, 
 caused the loss of untold treasure. 
 
 More recent investigations into the cau-e and spread of yellow 
 fever have only succeeded in verifying the work of Keed and his 
 commission in every particular and in adding very little t .ur kno\\ I- 
 edge of the disease. 
 
 Later researches by Guiteras in Habana, by the Puhlic I lealt h and 
 Marine-Hospital Service in VeraCruz, and lastly by a delegation from 
 the Pasteur Institute of Paris in Rio de Janeiro, all confirm in the 
 most convincing manner both the accuracy and comprehensive 
 of the conclusions of the American commission. It h well 
 
 said that Reed's experiments "will always remain as models in the 
 annals of scientific research, both for the exactness with which they 
 were adapted to the points to be proved, and the precautions t 
 that no experiment should be vitiated by failure t<> exclude all possihle 
 sources of error." 
 
 Appreciation of Reed's work was instant in the scientific world. 
 Honorary degrees from Harvard University and the Tim 
 Michigan were conferred upon him, learned societies and di-i mini 
 men delighted to honor him, and after his death Congress voted a 
 special pension to his widow. 
 
 To the United States the value of his services can not he estimated. 
 Ninety times has yellow fever invaded the country, carryii 
 and destruction, leaving poverty and grief. 
 
 NewOrlean-. Memphis, Charleston, Galve-t on, Portsmouth. Balti- 
 more, Philadelphia, New York, and many -mailer towns have been 
 swept by the disease. 
 
 The epidemic of 1853 cost New Orleans 8,000 lives, that of 1793 
 wiped out 10 per cent of Philadelphia's population. 
 
 The financial loss to the Ui he one epidemic of 1878 
 
 was estimated as amounting to $15,335,000, but suffering, panic, 
 fear, and the tears of widows and orphans can never be estimated. 
 however, if yellow fever should again cross our southern 
 border, there need be no disturbance of commerce or loss of prop- 
 in the slightest degree comparaMe with that which epidemics 
 in the past have caused. 
 
YELLOW FEVER. 13 
 
 The death of Maj. Reed took place November 23, 1902, in Wash- 
 ington, from appendicitis. It is gratifying to think that, although 
 his country and the scientific world were deprived of one from 
 whose future services more benefit to humanity might reasonably be 
 expected, nevertheless he was privileged before his life's close to 
 know that his discovery had been tested, and that a great city was 
 freed from her ancient foe, to know that his conscientious work had 
 contributed immeasurably toward the future prospects of an infant 
 Republic, and even more to the welfare of his own beloved country, 
 whose flag he had served so faithfully. 
 
 In the national capital and in the great cities of the United 
 States, there are stately monuments to the country's great ones. 
 Statues of warriors, statesmen, and patriots stand as silent wit- 
 nesses of a people's gratitude. Is there not room for the effigy of 
 Walter Reed, who so clearly pointed out to his fellow man the way 
 to conquer America's worst plague ? 
 
CHAPTER 2. 
 
 SKETCH OF THE LIFE OF MAJ. WALTER REED, SURGEON, 
 UNITED STATES ARMY. 
 
 By JEFFERSON R. KBAN, Major, Medical Corps, United States Amu. 
 
 Walter Reed, M. D., LL. D., M. A., major and surgeon . I 'nited 
 States Army, was born September 13, 1851, in Gloucester ('..unty. 
 Va., and was the son of tne Rev. Lemuel Sutton Reed, a leading 
 Methodist divine of that State. His ancestors came from North 
 Carolina, having been amonp the earliest settlers of that colony. I Ie 
 gave early evidence <>f the intellectual brilliancy and earnestness of 
 purpose which distinguished him in later years, and graduated in 
 medicine at the University of Virginia in 1869. 11 < i < >< >k 
 
 the degree of M. D. in Bellevue Medical College, New York City. He 
 served as house surgeon in the Brooklyn City Hospital and tin- city 
 hospital on Blackwells Island , and before the age < f '2 1 was appointed 
 a district physician in New York City. He was also appointed one 
 of the five inspectors of the board of health of the city of Brooklyn 
 at the age of 22. In 1875 he entered the Medical Corps of the Army. 
 and for 18 years thereafter performed the customary dm. 
 medical officer at various posts in different parts of the United > 
 and in the field. His military service included 1 f> changes of station. 
 with 4 years in Arizona, 5 in the Department of the IMatte. J in the 
 Department of Dakota, 3 in the South, and 3 years in the East. He 
 was promoted full surgeon with the rank of major December 4, 1 
 and at the time of his death was first on the list of majors in the 
 Medical Department of the Army. In the fall of 1890 he was a^iimed 
 to duty as attending surgeon in Baltimore, Md.. which M he 
 
 held for a year. He promptly embraced this opportunity to 1 
 special studies in bacteriology and pathology, and s< M.M won t 
 tion and esteem of Prof. Wmiam II. Welch. 
 
 This was the he^mnin^ 
 of a close friendship with that distinguished scientist \\hich lasted 
 until the untimely death of Maj. Reed, on November 23, 1" 
 
 In 1893 Maj. Keed was placed on duty in Washington as < nrator 
 of the Army Medical Museum and appointed the professor of bacte- 
 riology of the newly organized Army Mcdieal School. 
 
 In the 10 years subsequent to this date, in the intervals of his 
 routine duties and others which came to him as a medical officer, such 
 as member of examining hoards, teaching, investigation <>f numerous 
 sanitary questions, and making sanitary inspections, he was ahlc. l>\ 
 immense industry, to obtain a position ID the scientific worl.i 
 comes to few of those who are able to devote a lifetime exclusive^ to 
 such pursuits. 
 
 Of the numerous monographs which show his scientific work during 
 this time, all are credit a hie: nor do any show marks of can !- -n.-~- or 
 haste, in spite of the limited time which he had at Ids disposal. 
 14 
 
YELLOW FEVER. 15 
 
 In 1898, when typhoid fever prevailed so extensively in the camps 
 of the Volunteer Armies of the United States, Maj. Reed was put at f/ 
 the head of a commission Dr. Victor C. Vaughan, of the University 
 of Michigan, and Dr. E. O. Shakespeare, of Philadelphia, being the 
 other members to study the causation and methods of spread of that 
 disease. This investigation, which covered a period of more than a 
 year, was remarkable for the patience and skill with which a vast 
 number of details were assembled, and studied, and it marks a great 
 advance in our knowledge of this widespread disease. Among the 
 points of great value brought out were the importance of the common 
 fly as a carrier of infection in camps, and the frequency with which 
 the contagion of typhoid fever is in camp life spread from man to 
 man by immediate contact with each other or with bedding, tents, 
 and implements which have become infected. Strangely enough, this 
 report nas never been published in full, but only an abstract of it 
 containing some 240 pages, and, on account of the failure to publish 
 and disseminate the lull report, its conclusions are but little known 
 abroad or among the members of the medical profession in this 
 country. Many of the facts contained in it were rediscovered by 
 the English during the Boer War, and it is probable that its prompt 
 publication and dissemination would have saved many thousand lives 
 during that war. 
 
 The first work by Maj. Reed bearing on the causation of yellow 
 fever was in 1899-1900, when he overthrew the claim of the dis- 
 tinguished bacteriologist, Sanarelli, to have discovered the bacillus of 
 yellow fever, by his demonstration that the Bacillus icteroides (Sana- 
 relli) was an organism widely disseminated in this country and having 
 no causative relation to that disease. He began the special work with 
 which his name will always be inseparably associated as one of the ben- 
 efactors of mankind in June, 1900, when he went to Cuba as presi- 
 dent of a commission to study the infectious diseases of Cuba, with 
 special reference to yellow fever. The other members of this commis- 
 sion were Acting Asst. Surgs. James Carroll, Jesse W. Lazear, and 
 A. Agramonte. The time was most opportune for such investigation, 
 as the disease was at that time prevalent both in Habana and in the 
 little town of Quemados, near the camp of the American troops, and 
 it was plainly evident that the energetic measures of the American 
 military government to clean up the towns, disinfect, and enforce 
 other sanitary measures were without effect in preventing the spread 
 of this particular disease. Maj. Reed became convinced that proper 
 sanitation was not all that was needed, and that some other agent than 
 unclean conditions was responsible for the spread of the disease. 
 
 The transmission of malaria by a certain species of mosquito had 
 been recently demonstrated by the English military surgeon, Ronald 
 Ross. The theory had also been advanced both by a Mobile physician 
 and by Dr. Finlay, of Habana, that a mosquito was the agent for the 
 transmission of yellow fever; but these theories, being unsupported 
 by scientific demonstration, received no more attention than the vast 
 number of others which had been at one time or another advanced 
 with regard to this mysterious and deadly disease. 
 
 Dr. Reed's attention was attracted by a paper on the spread of yellow 
 fever in Ormond, Miss., by Dr. H. R. Carter, of the Marine-Hospital 
 Service, in which it was shown that although the period of incuba- 
 tion of the disease was 5 days, 15 or 20 elapsed before a house 
 
16 
 
 became infected aft- i<-k with yellow fever was carried into 
 
 it. :red that thoditfere! B6D tin 1 timoof incuhat ion and 
 
 the time required to infect a building was due to the fact that the 
 infective airent pas-. -o of d 'it in the body of 
 
 some biting insect as an intermediate host, and heat once determined 
 
 iments along thai lino. It wasevident to his mind 
 
 that the so! ul ion of this question, which meant SO much for the human 
 
 'erinined without cxperimci 
 
 human hoin^s. and ho tl.o military ^o\ ei : 
 
 Cuba, to a>k permission to conduct such experiments, and I 
 
 o liberally reward voh:; irho should suhmit them- 
 
 selves for O N ( W I promptly granted both, with a 
 
 ready a; iportance of the matter ami tho for 
 
 \\hich will entitle him to no small measu 
 * the f this di-cox 
 
 / Meanwhile, during n temporary ab-eneo of Dr. Koed in the Initrd 
 / States, his assistants, Dr. J .roll and Dr. Jre \V. L.-i, 
 
 / who had offored theiii-cl\ cs as the first volunt* . 
 demonstrated that moMpiitnes wmild 
 Dr. Carroll, who was the first oxporimon: 
 
 :.-k, but i d. Dr. La/, IK'! infected at 1 . due 
 
 to the fact that the conditions > v to the tran-mi i<m of the 
 
 disease by the moxpiito were not yet understood, but be was bit ton 
 while working in the yellow-fever' ward s(me\\hat later, and died a 
 
 martyr of science, working in behalf of humanity. Thi- only 
 
 fatality which occurred in these experiments. The fourth inonil 
 
 mission, Dr. Airramnnto, did not participate in the moMjiiiio 
 work of the commission until a later date, nor did he share their dan- 
 gers, as he was a Cuban and immune. 
 
 Immediately upon Dr. Heed's return arrangements \\cro made. \\ ith 
 assistance of the military governor, asstatol above, for a series of 
 experiments which, by precision of detail and ri-idnoss of control, 
 would admit of no uncertainity of interpretation and would bo a 
 
 non-tration, carrying conviction to every scientific and 
 unprejudiced mind. These experiments will, as stated by Prof. 
 William II. Welch, always remain as models in thoannal ntific 
 
 research, both for the exactness with which they were adapted to the 
 points to be proved and the precautions taken that no experiment 
 should be vitiated by failure to exclude all po>sihlo sources of 
 They were conducted in a camp especially constructed for the pur- 
 pose, about 4 miles from Habana, and appropriately named "Camp 
 Lazear.y The history of the work is best .iriven in' Dr. K< 
 words, in an article published in the Journal of Hygiene, Cambn 
 England. 
 
? 
 
 (/ 
 
 
 CHAPTER 3. 
 
 EXPERIMENTS CONDUCTED FOB THE PURPOSE OF COPING WITH - 
 
 YELLOW FEVER. 
 
 [Senate Document No. 10, Fifty-ninth Congress, second session.] 
 
 To the Senate and House of Representatives: 
 
 The inclosed papers are transmitted to the Congress in the earnest 
 hope that it will take suitable action in the matter. Maj. Reed's 
 part in the experiments which resulted in teaching us how to cope 
 with yellow fever was such as to render mankind his debtor, and this 
 nation should in some proper fashion bear witness to this fact. 
 
 THEODORE ROOSEVELT. 
 WHITE HOUSE, December, 5, 1906. 
 
 [Inclosure 1.] 
 [Memorandum for the President, through The Military Secretary of the Army.| 
 
 WAR DEPARTMENT, 
 OFFICE OF THE SURGEON GENERAL, 
 
 Washington, August 30, 1906. 
 
 The persons taking an important part in the investigations in 
 Cuba, which resulted in the demonstration of the fact that yellow 
 fever is transmitted by a species of mosquito, were three members of ^ 
 the board appointed to investigate epidemic diseases in Cuba- 
 Walter Reed, James Carroll, and Jesse W. Lazear and the indi- 
 viduals who submitted themselves for experimentation by receiving 
 the bites of infected mosquitoes, by receiving injections of blood from 
 yellow-fever patients, and by sleeping in bedding which had been 
 used by yellow-fever patients. 
 
 When the Yellow Fever Commission, composed of Walter Reed, 
 James Carroll, Jesse W. Lazear, and A. Agramonte, assembled in 
 Habana they had no thought of investigating the connection of the 
 mosquito with the spread of yellow fever. This idea came to Dr. 
 Reed after the board had demonstrated that the claim of Sanarelli, 
 concurred in by Wasdin and Geddins, that the Bacillus icteroides 
 was the cause of yellow fever was without foundation. Dr. Reed 
 then determined to investigate the theory of Dr. Carlos Finlay, 
 that the mosquito was instrumental in conveying yellow fever, which 
 theory Finlay had failed to demonstrate, and which was not then 
 accepted by scientific men. This determination was reached for the 
 reasons which are well stated in Dr. Kelly's biography, and was 
 original with Reed, not being suggested to him by anyone. The 
 final determination to investigate the mosquito theory was arrived at 
 during an informal meeting of the board (Dr. Agramonte being 
 absent) at Columbia Barracks on the evening before Dr. Reed's 
 
 79965 S. Doc. 822, 61-3 2 17 
 

 18 
 
 departure for the United States, early in August, l'.0l. It 
 agreed by these members of the board that in making the expcri- 
 ments on human beings, by which alone the demonstration could -ho 
 made, that they should submit themselves a^ subject- for experimen- 
 tation. To Dr. Lazear, who was familiar with mosquito \\ork. 
 assigned t lie duty of breeding and infect in-_: the moxjuitor-. while 
 Dr. Carroll was to continue the bacteriological work on which the 
 board had been engaged. 
 
 On August 2, 1900, before the mosquitoes were ready for the 
 /experiment, Dr. Reed was called back to Washington to prepare 
 / for publication the abstract of the report of the hoard appointed "m 
 I 1898 to investigate the spread of typhoid fever in tie volunteer 
 ' camps in the United States, of which board lie was president. This 
 vast work, of which the full report was pu hi ished by special authority 
 of Congress about a year after Dr. IJeed's d<>ath, by the onl\ 
 viving meml)er of the" hoard. Prof. Victor ('. Vaughan, of the Tni 
 versify of Michigan, was one of the most valuable contributio 
 science which has been made by the Surgeon General's ( Mlice. The 
 work of preparation of the abstract report had been brought t< a 
 standstill by the sudden death of the third member of the b 
 Dr. Kduard O. Shakespeare, of Philadelphia, and Dr. Recd'^ presence 
 at this time was essential for its completion. 
 
 During Dr. Reed's absence the inoculations by means of the 
 mosquito were begun. On August 11, Dr. Lazear made the lirst 
 experiment, but nine distinct inoculations on per>n-. iix-ludini: him- 
 selr and Acting Asst. Surg. A. S. Pinto, were unsuccessful. We know 
 now that these failures were due to two facts first, that patients 
 after the third day of the disease can not convey the infection to the 
 mosquito, and second, that after having bitten a yellow-fever case the 
 mosquito can not transmit the disease until after an interval 
 least 12 days. On August 27 one mosquito was applied to Dr. 
 Carroll, one which happened to fulfill both of these conditions, The 
 result was a very severe attack of yellow fever, in which for a time 
 his life hung in the balance. This was thus trie fiist expcrii: 
 case. The fever developed on the 31st of August, on which day Dr. 
 Lazear applied the same mosquito which bit Dr. Carroll with three 
 others to another person. This man came down with a mild but 
 well-marked case. 
 
 On September 13 Dr. Lazear, while on a visit to Las Am 
 Hospital (for the purpose of collecting blood from \<ll<>\\ 
 patients for study) was bitten by a mosquito of undetermined sp< 
 which he deliberately allowed to remain on the back of his hand until 
 it had satisfied its hunger. Five days thereafter he came do\sn. 
 without ot her exposure, with yellow fever, which p ! steadily 
 
 to a fatal termination. These three cases established in Keed's mind 
 the proof of the mosquito theory and made it, in the opinion of his 
 friends, an unnecessary and foolish ri>k for him. at his ap-. to submit 
 himself to inoculation. These cases, with his deduction-; t 1 
 were reported by the board in a paper called "The <>tio|o/\ of \-llw 
 
 fever A preliminary note." read before the American Public 1! 
 
 Association at Buffalo, \. V., October 22-26, 1900. He then 
 immediately returned to Cuba to undertake a second and mo in- 
 elaborate series of experiments which were made possible by the, 
 promise made to him by Gen. Wood on October 12, when told by 
 
YELLOW FEVER. 19 
 
 Reed of the experiments already made, to assist him with whatever 
 money was necessary. This, the second series of experiments, began 
 November 20 at an experimental camp near Quemados, called Camp 
 Lazear, and embraced 14 cases, of which the last was taken sick 
 February 10, 1901. Of these, 10 were mosquito infections and 4 
 were infected by injection of the blood of yellow-fever patients. All 
 of these cases recovered. 
 
 A third series of 6 cases was produced by Dr. James Carroll 
 the next fall to settle certain undetermined facts as regards the 
 etiology of the disease. The first of these cases came down with 
 the fever September 19, 1901, and the last on October 23, 1901. Of 
 these cases 2 were caused by mosquitoes and 4 by blood injec- 
 tions. None of them resulted fatally. The highly dangerous char- 
 acter of these experiments and the good fortune of the board in its 
 second and third series of cases is shown by the fact that Dr. Guiteras, 
 of Habana, in a series of 7 cases inoculated in Habana lost 3, bring- 
 ing his experiments abruptly to an end. 
 
 No enumeration of unsuccessful cases namely, those which failed 
 to cause the disease has been made, although it is obvious that the 
 persons undergoing such experiments exhibited as much courage as 
 those in which the disease was transmitted, This is especially true 
 of the cases occurring after the severe case of Dr. Carroll and the 
 fatal case of Dr. Lazear. Certain ones of these unsuccessful cases 
 deserve special mention, being those made with infected bedding 
 at Camp Lazear. In a specially constructed house at that camp, 
 which was intentionally ill ventilated and kept continually at a 
 summer temperature, was placed a large quantity of bedding taken 
 from the beds of patients sick with yellow fever in Habana and 
 soiled with their discharges. In this house Acting Asst. Surg. R. P. 
 Cook and two privates of the Hospital Corps slept continuously 
 from November 30 to December 19. Each morning they packed the 
 various soiled articles of bedding in boxes and unpacked them at 
 night, when they were used to sleep on. 
 
 From December 21, 1900, to January 10, 1901, the building was 
 again occupied by two nonimmune Americans under the same cir- 
 cumstances, except that an additional stock of very much fouled 
 bedding and clothing had been added to the collection, and these 
 men slept every night in the very garments worn by yellow-fever 
 patients throughout their entire attacks, besides making use of their 
 much soiled pillow slips, sheets, and blankets. A third couple of 
 Hospital Corps men succeeded these for an equal length of time. 
 None of these seven individuals contracted yellow fever, but the 
 courage and fortitude shown by them certainly equal that of those 
 who submitted to the bites of the mosquitoes, it being borne in mind 
 that belief in the transmission of yellow fever by infected bedding 
 and clothing was at that time practically universal, whereas the 
 mosquito theory had still very few converts. 
 
 After this brief history of this great discovery a statement of the 
 part borne by each of the more important participators in it is 
 necessary to a determination of the reward which would be appro- 
 priate to each. 
 
 Maj. Walter Reed, surgeon, United States Army, president of the 
 commission to investigate and study the epidemic diseases in Cuba, 
 died in Washington from appendicitis, November 23, 1902, at the 
 
20 YKI.I.oW KKVKK. 
 
 age of ~>1. At the time of his drat 11 the Secretary of War had said in 
 his report, which was then in press but not \ ei -/IN en <>ut : 
 
 The brilliant character of this ncimtilic :i<hi-\vni<-ni. ii- mrstimai.l.- \alu,> t,. 
 mankind, the savinp of thousands of lives, and thod. li h. Atlanticseacoaat 
 
 constant apprehon- .md special recognition from the Government f 
 
 the United States. 
 
 lleed is the ranking major in the Medical Department, and within a few months 
 will, by operation of law, booum- II.-UI.-M. mi . -l-n.-l. I a*k that the President I... 
 authorized to appoint him Assistant Surgeon <i. -ii.-r.il with th- rank ol 
 
 Gen. Leonard W.MM! said of him in an address delivered at a 
 memorial meeting of scientific men in Wa^hinirton, D. C., shortly 
 after his death: 
 
 I know of no other man on this side of the world wh<> has done BO mm h i"r humanity 
 as Dr. Reed. His diflCO very r !;v-s annualh thai 
 
 lost in the Cuban war, and saves the mnu-n -ial ini n-staof the world agn 
 cial loss each year than the cost of the Cuban war II. c -aim- t.. ( nl. ;i 
 one-third of tn f my staff died of yellow fever, and we were discouraged at 
 
 thefailure rto to control the dteaw. 
 
 In the months when the disease was ordinarily worst the disease was checked 
 and driven fr<>m Habana. That was the firet time in n.-arly 200 year- ihat th 
 had been rid of it. The value of his discovery ran nt l 
 who are not familiar with the conditions of tropical countric.- I |.- r . .,n.-r it will 
 be possible for v<'llw fever to gain such headway that fjuarantine wr m the 
 
 mouth of the Potomac to the mouth of th mde, Future <:.-m -rat i..[. 
 
 appreciate fully the value of Dr. Reed's services. His was the or 
 and controlling mind in this work, and the others were assistants only 
 
 In a letter from Prof. Welch to the Secretary of War he said : 
 
 Dr. Reed's researches in yellow fever are by far the most important contributions to 
 science which have ever come from any Army surgeon. In my judgment ihey are 
 the most valuable contributions to medicine and public hygiene wnich ha\ 
 been made in this country with the exception of the discovery of anapsthesi 
 have led and will lead to the saving of thousands of lives. I am in a positi< 
 that the credit for the original ideas embodied in this work \ ! 
 Reed. 
 
 Prof. Welch was Dr. Reed's teacher in bacteriology and was his 
 intimate and confidential friend, with whom h<> consulted ahotit the 
 details of the work in Cuba. 
 
 A bill prepared in this office for a pension for his widow, (><jual in 
 amount to his monthly pay, was passed, but the amount was so cut 
 down that while it keeps the wolf from the dor it does mt pro- 
 vide an adequate and comfortable income. It i^ not probable, how- 
 ever, that Congress would increase this pension, and an e!l'>rt has 
 been made to supplement it by the raising of a fund of SiM.onn by the 
 Walter Reed Memorial Association, incorporated for this pm 
 in the District of Columbia. The interest on this fund will be ^ivcn 
 Mrs. Reed during her lifetime, and the principal, after her death, will 
 be devoted to some form of memorial. This fund lacks at present 
 about $6,000 of comnlet ion. The existence of tin ution, >hould 
 
 its hopes be attained, does not . however, absolve the nation from the 
 obligation of a fitting rer<, L r n jt ion for this trreat work, and it is the 
 opinion <.f the undersigned, which, it U believed, is Chared by the 
 vast majority of physicians in the United States, that < 
 should erect a statue to Walter Reed in Washington. The assist 
 of the President in inducing Con do so is re<me-ted. 
 
 The second member of tne cniun i js-i .MI wii Dr. James Carrofl, ;i 
 that time acting assistant surgeon, I* nit. my. 
 
 Dr. Carroll is now - r ,_' years old. Me entered the milhan 
 June 9, 1874, and served as private, corporal, sergeuni and ho-pit.il 
 
YELLOW FEVER. 21 
 
 steward from that date to May 21, 1898, when he was appointed acting 
 assistant surgeon. He was appointed first lieutenant and assistant 
 surgeon in the Medical Corps October 27, 1902, which rank he still 
 holds. 
 
 Dr. Carroll was Dr. Reed's truest assistant and coadjutor from the 
 inception of the work which resulted in the discovery of the method 
 of propagation of yellow fever. As stated above, the third series of 
 experiments were performed by Dr. Carroll alone, Dr. Reed having 
 been refused permission to return to Cuba to complete his work. 
 
 Dr. Carroll was the first experimental case of yellow fever, and he 
 suffered a very severe attack, to which he attributes a heart trouble 
 from which he now suffers. At the time of undergoing this experi- 
 ment he was 46 years old, an age at which the risk from this disease 
 is very great, as its mortality rapidly increases with age of patient. 
 He had at that time a wife and five children who had no other means 
 of support except his pay as an acting assistant surgeon. 
 
 It is recommended that Congress be asked to pass a special act pro- 
 moting Dr. Carroll, on account of his services in connection with this 
 discovery and the courage shown by him insubjecting himself to experi- 
 ment, to the rank of lieutenant colonel, the number of medical officers 
 in that grade being increased by one for that purpose ; also his name 
 and effigy should appear on the monument to Walter Reed. 
 
 Dr. Jesse W. Lazear was the third member of the commission. 
 
 Dr. Lazear was a native of Baltimore and a graduate of Johns Hop- 
 kins University, afterwards getting his professional degree at Columbia 
 University and Bellevue. At the time he incurred his death in the 
 course of these experiments, as above mentioned, he was 34 years 
 old. He left a wife and two young children, the younger a little son 
 born a few months before his death, whom he never saw. Mrs. Lazear 
 received from Congress a pension of $17 a month with $2 additional 
 for each of two minor children until they reach the age of 16. Also 
 a battery in Baltimore Harbor was, by direction of the Secretary of 
 War, named in his honor. It is believed that this recognition on the 
 part of the nation for his services is utterly inadequate. His widow's 
 pension should be increased to $100 a month, and steps should be 
 taken to perpetuate his name in connection with the Walter Reed 
 monument above suggested. 
 
 Dr. A. Agramonte was the fourth member of the Yellow Fever 
 Commission. He was a Cuban by birth, an immune to yellow fever, 
 and having been assigned other work, took no part in the first series 
 of experiments with regard to the conveyance of the disease by the 
 mosquito, of which, in fact, he was not at the time cognizant. Being" 
 an immune, he ran no risk in connection with this work, and it is 
 believed that his contributions to it have been sufficiently recognized 
 in the association of his name with the other members of the com- 
 mission who brought about this great discovery. 
 
 Twenty-three of the men who submitted themselves for experiment 
 by the board contracted yellow fever, beginning with Dr. James Car- 
 roll, who was taken sick August 31, 1900, and ending with John R. 
 Bullard, who was taken sick October 23, 1901. 
 
 Conspicuous among them was John J. Moran, a civilian clerk 
 employed at the headquarters of Gen. Fitzhugh Lee, at Quemados, 
 who was one of the earliest volunteers for the second set of experi- 
 ments, and whose action was dictated by the purest motives of 
 
22 -IX>W FEVER, 
 
 altruism and self-devotion. Mr. Moran disclaimed, before submit t in*: 
 to the experiments, ai , and has never accepted 
 
 . ahhou-li he was olleivd the $200 which the liberality of the 
 military gov .abled the commission to give to each < \ 
 
 mental pat inn. the members of the board excepted. Such 
 modesty that he has made no effort, so far as known to this olliee, to 
 make known his connection \\ith these experiments and reap the 
 is so justly dne him. Mr. Moran was a native of Ohio. 
 His proem address is not kno\\n to t his ollice. The first inoculations 
 in thecaseol f>r some reason unsuccessful. <>n Novem- 
 
 ber 26 and 29. Ho did not suifer an attack until after the third 
 inoculation, on December 
 
 The same remarks apply to the lir.-t experimental case of the second 
 set, Pvt. John K. K hospital corps, who volunteered at the 
 
 same time \\ith Moran and equally disclaimed anv doire for re\\ard. 
 
 Pvt. l\i iii'j'T did not leave Cuba immediately after the 
 inents. as , lid Mr. Moran. and tl 'lie military author!. 
 
 able to reward him in some measure alon: with other e men 
 
 who volunteered for these experiments. lie was promoted acting 
 hospital steward, presented with a gold watch by the chief surgeon 
 of the department in the presence of all the medical officers and 
 pital c,.rps men on duty at Columbia Barracks, and also re 
 present of $115 in cash. He took his discharge November 14, 1 
 and has since (on December 17, 1903) made application for pen-ion. 
 This was refused for lack of evidence that his ill-health was incident 
 to the service. 
 
 Of the other experimental cases, seven were Spanish immi^r 
 who submitted to experiments purely for the money which t ! 
 promised. With regard to those who were American soldiers, how- 
 ever, 10 in number, in addition to those already mentioned, ii 
 not be doubted that, although they received pecuniar. 
 desire to assist in what they appreciated was a great and 
 work, together with a spirit of adventure, was th- rful 
 
 motive. The same is true of the last experimental ca-e. Mr. John K. 
 Bullard, a graduate of Harvard, where he was a distinguished at 
 and captain of the university crew. The names of en, with 
 
 the dates of then* attack, is appended with t!ii> rep 
 
 It remains to mention Dr. Rooert P. Cook, actii banl SUIL 
 
 and the six privates of the hospital corps, who were for -jn n 
 shut up in the infected bedding house at Camp La/ear. 'I 
 experiments, which were absolutely necessary to demonstrate 
 vellow fever could not be carried otherwise than by the n 
 had for these men, so far as they knew, an e<jual element 
 with the other experiments and had in addition Mich : 
 
 disagreeable features as to test to the full their hardihood and 
 nee. Much of the balding upon which they ^-lept and which 
 ttter were required daily to handle, was so soiled with the di 
 
 of the -ick as to be ' > the nse and eye. and 
 
 experimenters actually slept in the pajamas and >hert -. which had 
 been worn by severe cases of yellow fever. The names of 
 men are appended to the list given below of experimental 
 yellow fever. 
 
 It will be observed that three of these men Folk. .1. ami 
 
 afterwards submitted to the nioM|iiito inoculation or 
 
YELLOW FEVER. 
 
 23 
 
 blood injection in order to demonstrate their nonimmunity at the 
 time of the first experiment. 
 
 It is believed that the names of all the Americans on this list 
 should be placed on a tablet in connection with the monument to 
 Walter Reed. 
 
 From the foregoing it will be seen that the total disbursements, 
 of this great nation in the way of rewards for those who made possible 
 this discovery and their families, amounts to $146 a month. As to] 
 its value to the American people attention is invited to the quota- 
 tions from Gen. Wood and Prof. Welch given above, and others given 
 in the inclosed circulars published by the Walter Reed Memorial 
 Association. 
 
 How discreditable appears this niggardly provision when com- 
 pared with the action of the English Government which more than 
 a century ago, when the purchasing power of money was far greater 
 than at present, gave to Jenner, the discoverer of vaccination, grants 
 amounting to 30,000 sterling. He also received from a subscrip- 
 tion in India 7,383 sterling, while the Reed Memorial has so far 
 succeeded in raising only a little over half that sum. 
 
 It is believed that if the President would exert his great personal 
 influence in furtherance of the aims of that association its task 
 would be soon completed. 
 
 R. M. O'REILLY, 
 
 Surgeon General, United States Army. 
 
 Names of persons who submitted to experimental inoculation of yellow fever, Cuba, 
 
 1900-1901. 
 
 Infected by mosquitoes. 
 
 James Carroll Aug. 31, 1900 
 
 X. Y. (American soldier) Sept. 6,1900 
 
 John R. Kissinger Dec. 8, 1900 
 
 Nicanor Fernandez Dec. 13, 1900 
 
 5 Antonio Benigno Do. 
 
 Becente Presedo Dec. 15, 1900 
 
 John J. Moran Dec. 25, 1900 
 
 Jose Martinez... Jan. 3,1901 
 
 LeviE.Folk Jan. 23,1901 
 
 Clyde L. West... Feb. 3,1901 
 
 James L. Hanberry Feb. 9,1901 
 
 Charles G. Sonntag Feb. 10, 1901 
 
 13 Pablo Ruiz Castillo Sept. 19,1901 
 
 14 Jacinto Mendez Alvarez . Oct. 13, 1901 
 
 Infected by injection of blood. 
 
 1 Warren G. Jernegan.. .. Jan. 8,1901 
 
 2 William Olson Jan. 11,1901 
 
 3 Wallace Forbes... Jan. 24,1901 
 
 4 JohnH. Andrus Jan. 28,1901 
 
 5 Manuel Gutierrez Moran ... Oct. 20, 1901 
 
 John R. Bullard Oct. 23, 1901 
 
 Infected by injections of filtered blood serum. 
 
 1 P. Hamann, Twenty-third Battery Coast Artillery Oct. 19,1901 
 
 2 A. W. Covington, Twenty-third Battery Coast Artillery Do. 
 
 Exposed to fomites. 
 
 1 Dr. R. P. Cooke, acting assistant surgeon 
 
 2 LeviE.Folk......... 
 
 Warren G. Jernegan 
 
 4 James L. Hanberry 
 
 5 Edward Weatherwalks (bitten once, negative; refused after Hanberry came down) . 
 James Hildebrand (offered himself, but was declined on account of age) 
 
 7 Thomas M. England .. 
 
 Taken sick. 
 
( H M'TKK 4. 
 
 
 
 YELLOW-FEVER COMMISSION. 
 [Senate Document No. S20, Sixty-first Conureas. woond session ] 
 
 WAI: DKPAI: IMKN i . 
 OFFICE OF TH \L, 
 
 jtfon, April 29, 1910. 
 
 MY DEAR SENATOK: It irive- m- irreat pleasure to comply with 
 the re|ue>t contained in your In \ |>nl _'. to furni-h you With a 
 
 report of the occurrence^ which led to the appointment of the \ello\\- 
 t omission, of which Maj. Walter Keed \\a^ presidi ! the 
 
 names of the pe >imerted with the experiments of tlie (-(.in- 
 
 mission, together with other data which i< available concernim: t hem. 
 
 Surg. Gen. Sternberg was for many years one of tlie leading 
 auth ;i the world on the subject of yellow fever, and had made, 
 
 under the direction of the President of the t'nited Stab 
 laborious investigations as to its cause in Ilak-ma. Bra/il. and Mexico. 
 These investigations were UIIMH < -e ful because, as we now know, tin- 
 organism of yellow fever is invisible to the micro>c..pe. but they 
 served a valuable purpose in enabling Dr. Sternberg to dU| 
 the claims of other investigators to have discovered the causative 
 organism and to have prepared protective inoculations ajrainM the 
 disease. His attention n a ving been attracted by the claim of Sana 
 relli, of Buenos Aires, to have discovered the cause of yellow 
 in the Bacillus icteroides, he ordered Maj. Keed. at that time pro- 
 fessor of bacteriology in the Army Medical School, to study this 
 organism in connection with an organism discovered by Stern her*: 
 in t he bodies of yellow-fever patients in llabana. and name<l by him 
 bacillus X. This investigation was continued by a board run-Mini: 
 of Maj. Walter Reed, surgeon, United States Army, and A 
 Asst. Surgs. James Carroll, Aristides Ai;ramonte. and Jo-e \\ . 
 Lazear, United States Army, which was appointed t<> meet at (amp 
 inbia, near Habana, Cuba, in May, !!>()(). The instruction- to 
 Maj. Kced, president of this board, included the following: 
 
 You will naturally give special attention to qu. iiini: i ili- < -ti..!..^ and 
 
 prevention of yellow iever. As you are familiar \viih \\liai has aln-ady Keen done by 
 other bacteriologists in (fait field of imrwtigation, I ^\\\,,\ r..n.-i<l-r it aeceflBaryto 
 you any suggestions or detailed i n-i ru< ii irident that the mo0t imp 
 
 Question which will occupy your attention is that \vhi-h relates t ih- < -liolo^y 
 
 h-'-a-.- 
 
 You will also take advantage of such <.|.|><>rt unit if* an may <fi. -r f. .r i h. 
 infectious diaeanes, and epecially of the mai ;n_- in the i-lan-1 <>i 
 
 An important queetioD Ln connection with the diMaaee of toopical 
 al cou nines relates lo 1 1; i>rilcatta' fouhuh 
 
 Htrangers are especially Hiil. j! sh-.u' 1 ..! ..p|...r 
 
 luriiry for i h-. -t ud y of leprosy in tip ^pital in i A m-nf iii 
 
 should also be given to ih* n, 
 prevail, the etiology of which has u<- :mii. ly determined. 
 
 24 
 
YELLOW FEVER. 25 
 
 One member of the board, Dr. Aristides Agramonte, lived in 
 Habana, and another, Dr. Jesse W. Lazear, was already stationed at 
 Columbia Barracks, having joined there on February 13, 1900. The 
 remaining members of the board arrived in Cuba June 25, 1900. 
 They were able to prove conclusively that in 18 cases of unmistakable 
 yellow fever investigated from beginning to end bacillus icteroides was 
 not present and that this organism could not be the cause of the dis- 
 ease. These conclusions were diametrically opposite to those of Drs. 
 Wasdin and Geddings, of the Marine-Hospital Service, who likewise 
 at that time were studying yellow fever in Habana, and who con- 
 firmed the findings of Sanarelli. The board then proceeded to investi- 
 gate the theory advanced by Finlay, that yellow fever was conveyed 
 by mosquitoes. A full history of these experiments has been pub- 
 lished in the reports of the board, and a brief account of it, together 
 with a list of the persons who submitted to experimental inoculation, 
 was given in a memorandum prepared for the President by this office 
 on August 30, 1906, and transmitted as a special message to Congress 
 on December 5, 1906. It was published as Senate Document No. 10, 
 Fifty-ninth Congress, second session, a copy being inclosed. 
 
 Before taking up individually the men concerned in these experi- 
 ments, in order to state what is known about them at the present 
 time, it may be mentioned that the Spaniards who were inoculated 
 did so for the pecuniary inducement offered them. After receiving 
 the reward offered them by the liberality of the military government 
 of Cuba, $200 for each person successfully inoculated, they passed 
 from the scene and nothing further is known concerning them. 
 While their names should be preserved as a matter of historical 
 interest, it is considered that they have been well rewarded for their 
 share in the matter, especially as the idea of assisting in the advance- 
 ment of science was not a controlling motive for their action. Also 
 it should be stated that it can not be demonstrated that these experi- 
 ments caused the death or subsequent ill health of any of the partici- 
 pants, with the exception of Dr. Lazear and of three individuals who 
 died in the course of the experiments which were conducted by Maj . 
 Gorgas and Dr. John Guiteras at Las Animas Hospital, Habana, 
 between February and December, 1901, which will be referred to later. 
 
 In view of the facts which have come to the attention of this office 
 since the preparation of the memorandum for the President, it is 
 believed that that memorandum does not do justice to the importance 
 of the part which Dr. Agramonte took in these investigations. Dr. 
 Agramonte has made the following statement with regard to the 
 work of the board, 
 
 In the investigations of the board with reference to Bacillus icteroides, 
 had the bacteriological work, Dr. Agramonte _tbf> aujgvpiya.nd gross pathology, Dr. 
 .n-ssf \Y. Lazear the microscopical pathology. 
 
 "InTune, lyuu, Ur. Agramonte was senl to the city of Santa Clara to investigate the 
 outbreak of yellow fever in that city, and in July he was sent to the city of Pinar del 
 Rio to investigate the outbreak of yellow fever among the American troops, which 
 the surgeons stationed there had failed to recognize as such. Dr. Agramonte promptly 
 recognized the true character of the disease, and was joined there by Maj. Reed a 
 couple of days later. It was there that for the first time the probability of mosquito 
 agency in transmitting the disease was seriously discussed by members of the board, 
 and it was decided to carry out some research in this direction. 
 
 As Dr. Lazear had obtained considerable training in mosquito work while in Italy, 
 and none of the other members of the board had any, it was agreed that he take up 
 this part of the work in the beginning. Dr. Carroll continued to investigate the 
 bacteria and Dr. Agramonte the pathological anatomy of yellow fever. 
 
26 YELLOW FEVER. 
 
 Maj. Reed at this time returned to Washington for the purpose of com plot in 
 report upon "Typhoid Fever in the Army," in collaboration \v hakeepeare 
 
 La*ear began to breed, dissect, classify. and equitoes, in which work Carroll 
 
 and Agramonte took little <>r no part. Now and then Lazear would apply tl 
 
 1 
 and several other persona had been bitten .-e\eral times by mosquitoes \ 
 
 . vioualy had ft*. 1 tat 1 ho theory 
 
 transmission was gradually I 'I. until Carroll fell the :Juh <>f 
 
 AUL.VSM !'"*> . entirely inn.., , ,,i ,,f the real nature -f his illn. -. 
 
 Suspecting the or . "s. Lazear and 
 
 inonte d . h presumably had caused Carroll's att:i 
 
 . app hr>t nonimmune individual \vh miuht all'.w \\. 
 
 31, the sai were 
 
 applied to an A 
 
 ! id he ir out of said reser- 
 vation before 1, 
 our minds the fa- 1 that he had been im"e-ied i.\ the mcequi to bites, 
 
 Dr. ' :M> Mill Hit'fen: severe al disease, 
 
 Drs. Lazear and Agramonte decided to communicate these results to Maj. Reed, who 
 was > ton. 
 
 n> Maj. Reed's arrival in Tlabana, Dr. Lazear became infected w 
 i taking place on the 25th of September. 
 
 Dur !'s convalesce) i ard decided that the resi 
 
 tion were so far sufli 'ivincini,' to justify their pre>- 
 
 preliminary note. before the coming meeting of the American Publ 
 at Indianapolis, Ind. (October, 1900). 
 
 Reed went north for this purpose, and while Carroll took a short va 
 recuperate from his recent attack, Dr. Airramonte v, i with br< 
 
 :inir rni.sijuitoes, keeping them at the division laboratory, -which was under his 
 care in Habana, in preparation for the work which the board intended to carr 
 after the Indianapolis meeting. 
 
 When Maj. R<-ed returned from the States, moral and m 1 was obt: 
 
 from Gen. Leonard Wood, commanding the division, and we determined to 
 out an investigation exclusively based upon the mosquito il 
 
 we knew nothing of Beauperthuy then, who in 1853 had defended practically the 
 same theory. 
 
 While th'e experimental station, afterward named Camp Lazear, in honor i 
 memory of our deceased colleague, was being established, the care of the moe<j 
 and their infection by applying them to yellow-fever cases, way in i 
 Agramonte, at the division laboratory: when the permanent mosquito building" was 
 erected at Camp Lazear (Dec. 1, 1900), these mosquitoes were tun m Dr. 
 
 Carroll for his care. It devolved then upon Dr. Agramonte to wlect the mos. 
 from those kept by Dr. Carroll and apply them to nonimmunes, as well a- t. make all 
 subsequent direct inoculations, and to obtain the nonimmunes (Spaniards) f 
 purpose, until the end of the work in Cuba. 
 
 Let me add that the best friendship existed between all the m. "oard, 
 
 and from the beginning of their work it was a-re. <1 thai the Imnnr ol Itn was 
 
 to be shared by all alike, as the labor was so evenly nhan <1. I - 
 not been the case, let us hope through no fault of tl 
 
 Reed and Carroll had been connected in laboratory work I years, and Dr. 
 
 Agramonte had also worked at the Army Medical Museum l.aborat. > Lazear 
 
 and Agramonte were classmates, having graduated from the College of MS and 
 
 Surgeons, New York, in June 1892. 
 
 T<> the absolute truth of the above statement 
 
 In testimony whereof I affix my signature in the August :\\, 1908. 
 
 ARISTIDEH A- M I > 
 
 1. Mai. Waltor Rood, surpM.n. I'mic*! - \ rm\ . <lir<l in Well- 
 ington, I andicitb, November 51. Hi- 
 widow. Knii Reed, is receiving a pension of $125 a month. 
 
 2. llaj. James Carroll was promoted iv licutcm-nt i 
 by special act of Congress March '., P.n7. H (> 'I" 1 ' I in ^';i 
 
 l>. < .. of myoninlilk Scplrinl. Jennie II. 
 
 nth, 
 
 apj. \rinv appropriation hill. 
 
YELLOW FEVER. 27 
 
 3. Dr. Jesse W. Lazear, contract surgeon, United States Army, died 
 at Camp Columbia, Cuba, of yellow fever, September 25, 1900. His 
 widow, Mabel M. Lazear, since his death has received an annuity of 
 $125 a month, appropriated from year to year in the Army appropria- 
 tion bill. 
 
 4. Dr. Aris tides Agramonte is the only living member of the board. 
 He is professor of bacteriology and experimental pathology in the 
 University of Habana and has never received, either directly or indi- 
 rectly, any material reward for his share in the work of the board. 
 
 5. The name of the American soldier, XY, who was the subject of 
 the second experiment, was concealed at the time, because the experi- 
 ment was macte without military authorization. It has been recently 
 ascertained to be William H. Dean, private, Troop B, Seventh Cav- 
 alry. He has never received any reward. He was discharged August 
 17, 1902, by reason of expiration of term of service, and there is no 
 further record of him at the War Department. His residence at 
 enlistment was given as Grand Rapids, Mich. His case has special 
 importance as having been the first experimental case which was com- 
 plete in the matter of control, for Dr. Carroll's, which came four 
 days earlier, was defective, by reason of his going into the infected 
 zone during the period of incubation. 
 
 6. John R. Kissinger, private, Hospital Corps (see p. 6, President's 
 message). Kissinger volunteered for service at the beginning of the 
 Spanish War in Company D, One hundred and fifty-seventh Indiana 
 Volunteers, and after his discharge enlisted in the Hospital Corps. 
 After the first secret experiments of the board, which included the 
 cases of Dr. Carroll and Pvt. Dean, became known and the experi- 
 mental camp was established and named Camp Lazear, Kissinger 
 and Moran were the first to volunteer as subjects for experiment. 
 Moran was first bitten, but Kissinger was the first to be attacked, on 
 December 8, 1900. He recovered and was afterwards promoted to 
 be acting hospital steward, and discharged November 14, 1901, at 
 Columbia Barracks, Cuba. It is understood that his health after- 
 wards failed so that he became entirely dependent upon -the labor of 
 his wife for support. He was pensioned at the rate of $12 per month, 
 by the act of March 2, 1907. This amount is considered quite 
 inadequate either for his support or as a recognition of his services. 
 A bill granting an increase to $125 per month was favorably reported 
 and incorporated in Senate bill 6272 and passed the Senate February 
 15, 1910, but was objected to by the Committee on Pensions of the 
 House of Representatives. The report of the Senate committee (No. 
 574) is inclosed. 
 
 7. John J. Moran (see p. 6, President's message). Mr. Moran has 
 never received any material reward for his most creditable services. 
 After leaving Cuba he completed his education by a course of study 
 at the University of Virginia, and is at present living at Panama, in 
 the employ of the Isthmian Canal Commission. He is at present an 
 applicant for appointment in the Consular Service for which, by reason 
 of his excellent knowledge of Spanish and other qualifications, he is 
 well fitted. 
 
 8. Levi E. Folk, private, Hospital Corps, volunteered to be bitten 
 by infected mosquitoes and was taken with yellow fever January 23, 
 1901. He is still in the military service, and is a sergeant, Hospital 
 Corps, stationed at the recruit depot, Columbus Barracks, Ohio. 
 
28 YELLOW FEVBE. 
 
 He received a donation of $300 from the appropriation made by Gen. 
 Leonard Wood for ; :eriments. 
 
 9. Clyde L. \Ye-t. pn\ pital Corps, volunteered to he hit ten 
 hy infected - toes at ( nd was taken >i-k \\ith 
 yellow fever Februa- !. II,- \\a> di-char<:ed from tli. 
 
 July 10, 1902, at Fort M\. I his subsequent addiv 
 
 unki \ -d .-i donation of $200 from the appropriation 
 
 made by Gen. Leonard Wood for the>e experiments. 
 
 10. James L. Han private, Hospital Corps, volunteered to 
 be bitten by infected mosquitoes, and in lence, was taken -i. k 
 with yellow fever at Camp La/car Kehruary '., 1901. He des< 
 the service April 4, 190'J. at the general hospital. \Va-hin.Lrton 
 racks, D. C. His subsequent addre is unknown. II ed a 
 donation of $300 from the appropriation made by Gen. Wood for 
 these experiments. 
 
 11. Ch; Sontag, private, llo-pital Corps, volunteered to he 
 hitten hv infected mosquitoes, and was in consequence taken 
 
 with yellow fever at Camp Lazear Fehniaiv in. p.ni. He was dis- 
 charged from the service Deeemher 1'J. UMI'I. ;1 t Columhia Barracks, 
 Cuba, and hl8 Subsequent address is unknown. He iv.eived a dona- 
 tion of $200 from the appropriation made by ( Jen. Leonard Wood for 
 these experiments. 
 
 12. Warren Gadsden Jernegan. private. lhpital Corps, was 
 infected with yellow fever hv the injection of blood, and taken >iek 
 January 8, 1901. He was discharged November 16, r.< !um- 
 bia Barracks, Cuba. Address given, care olM. A. Fouler. MeMeekin, 
 Fla. He received a donation of $300 from appropriation made by 
 Gen. Wood for these experiments. 
 
 I.S.William Olsen, private, Hospital Corps, was infected with 
 yellow fever by injection of blood, at Camn Lazear, and taken ^i< k 
 January 11, 1901. He was discharged November 15, 1901. at 
 Columbia Barracks, Cuba. Address given, care of C. Olsen. Plum 
 . Wis. He received a donation of $200 from the appropriation 
 made by Gen. Wood for these experiment -. 
 
 14. Wallace W. Forbes, private, Hospital Corps, volunteered to be 
 infected with vellow fever by the injection of hlo<'d. at ( !amp I A 
 and became sick January 24, 1901. lie was di-(hai_:ed March 1, 
 1905, at Fort Hancock, N. J. Address given. < -'. W. For 
 
 Minneapolis, Minn. This soldier received a donation of $200 1 
 the appropriation made by Gen. Wood. 
 
 1"). John II. Andrus, private, Hospital Corps, volunteered and was 
 infected with yellow fever by injection of hlood. at Camp and 
 
 became sick January 28, 1901. He was discharged April 1M, i 
 at Camr> Geo. H. Thomas, Chickamauga, Trim, lli- -ul>-r<jurnt 
 
 address is not known. He received a donation of S'Jnn from the 
 appropriation made by Gen. Wood. 
 
 John R. Bullard, native of Massadm-i tuate of 
 
 vard Univei here he was a di-t in:ui>hed athlete, and 
 
 eOffagcd iii farming in <ul>a. volunteered and was infected with 
 vellow fever by the injection of blood. He hecame sick OH 
 1901. 
 
 1 , Paid I lamann, private, Twenty-third Comp. i tillery. 
 
 vohmteere.I and was infected with yellow fever h\ injection of filtered 
 blood serum and became sick October 19, 1901 . He \\ a 
 
YELLOW FEVER. 29 
 
 July 19, 1902, by reason of expiration of term of service. His address 
 given at time of enlistment was care of August Hamann, Moline, 111. 
 Present address not known. This soldier received a donation from 
 the appropriation made by Gen. Wood for these experiments. 
 
 18. Albert W. Covington, private, Twenty-third Company, Coast 
 Artillery, volunteered and was infected with yellow fever by injection 
 with filtered blood serum and became sick October 19, 1901. He is 
 still in the service, and is serving as sergeant, Twenty-third Company, 
 Coast Artillery Corps, at Fort McKinley, Portland, Me. He received 
 a donation from the appropriation made by Gen. Wood for these 
 experiments. 
 
 19. Dr. Robert P. Cook (see President's message, p. 7). Dr. Cook 
 entered the medical service June 9, 1900, as contract surgeon, from 
 the State of Virginia. He left the service at his own request, Decem- 
 ber 22, 1904. His present address is Winchester, Va. 
 
 The demonstration made by Dr. Cook and the men with him that 
 yellow fever could not be transmitted by infected clothing and other 
 inanimate objects was of the utmost importance to commerce and 
 has immensely simplified the preventive measures to be taken against 
 this disease. He was shut up in a house with infected bedding for 
 20 days, together with the following privates of the Hospital Corps, 
 who received a donation of $100 each from the appropriation given 
 by Gen. Wood for these experiments: 
 
 20. Edward Weatherwalk. Discharged the service December 12, 
 1901, at Columbia Barracks, Cuba. Subsequent address not known. 
 He received a donation of $200. 
 
 21. James Hildebrand. Still in service as private, first class, 
 Hospital Corps; stationed at the recruit depot, Columbus Barracks, 
 Ohio. He received a donation of $100. 
 
 22. Thomas M. England. Still in service as sergeant, first class, 
 Hospital Corps; stationed at Fort Ward, Wash. He received a 
 donation of $100. 
 
 In addition to these, Pvts. Folk, Jernegan, and Hanberry under- 
 went the exposure to infected bedding prior to being bitten by the 
 infected mosquitoes. 
 
 Additional experiments by Maj. W. C. Gorgas and Dr. John 
 Guiteras, at Las Animas Hospital, Cuba (see vol. Ill, p. 386, civil 
 report of Gen. Wood, 1901): 
 
 (1) Vergera; Spaniard. Infected by mosquitoes February 23, 
 1901; recovered. 
 
 (2) Carro; Spaniard. Inoculated by infected mosquitoes August 8, 
 1901; died. 
 
 (3) Represas; Spaniard. Infected by mosquitoes August 8, 1901; 
 recovered. 
 
 (4) Campa; Spaniard. Infected by mosquitoes August 9, 1901; 
 died. 
 
 (5) Taylor, John R. ; Englishman. Infected by mosquitoes August 
 13, 1901; recovered. 
 
 (6) Miss Clara Louise Maass, of East Orange, N. J., aged 25. 
 Trained nurse in Las Animas Hospital. She served as trained nurse 
 in Medical Department of the Army during the Spanish War. She 
 volunteered and was bitten by infected mosquitoes August 14, and 
 died of yellow fever August 18, 1901. 
 
30 
 
 (7) Varela; Spaniard. Infected by inn>(|uitoos August i l, 
 recovered 1 . 
 
 (8) Alonso; Spaniard. Infected by mosquitoes August 2J. 
 recoven 
 
 (9) Castillo; Spaniard. Infected by mosquitoes September 16, 
 1901, \>y l>r. Carroll; recovers 1. 
 
 ml. Infected 1>\ mosquitoes Novrm!><>r 17, 
 1901; recovti 
 
 The amount of the donations received by these volunteers is imt 
 known. 
 
 iv were 22 cases of experimental Yellow fever jn-oduccd hy Ueed. 
 Carroll, and Lazear, and Id in the experiment^ ran in I on in Ilahana 
 by Gorgas Hi Bras. There \\ei-e aUo 7 persons \\lio underwent 
 
 the very trying experiment of sleeping in infe<-ted bel<ling. 
 
 It luis been impracticable to make a complete list of the persons 
 who submitted to the bites of mosquitoes but who failed to become 
 infected, although it must be reco^ni/ed that in many cases these 
 exhibited as hjgfi a degree of courage as those who suffered an attack 
 of yellow fever. 
 
 It is hoped that the Senator will be able to obtain the consent of 
 Congress to the erection of a monument which will be worth 
 Maj. Reed, who conceived and carried out in so admirable a manner 
 these epoch-making experiments, and to the is who shared in 
 
 his labors and to the persons who offered their bodies for these dan- 
 gerous experiim : 
 
 Aery respectfully, GEO. II. T<>i:\ 
 
 Surgeon General, United States An 
 
 Hon. ROBERT L. Owi 
 
 United States Senator, Washington, D. C. 
 
 [Senate Report No. 574, Sixty-first Congress, second session.] 
 
 The Committee on Pensions, to whom was referred the bill (S. 7252) granting an 
 annuity to John R. Kissinger, have examined the same and report: 
 
 A bill granting an increase of $125 per month to, Mm K. Kissinger, the apt 
 herein, was favorably reported by your committee and incorporated in Senate hill 
 6272 at this session ami passed the Senate n i-VI,niary l. r >, 1!MO. 
 
 The Senate report No. 210, which contains a very full statemcr Cervices of 
 
 this soldier and the grounds upon which his right to increase of pension is recogni/< 1 . 
 is as follows: 
 
 S. 4479. John Kissinger, the claimant, was one of the bravest of soldiers who H 
 in the Spanish- American War. For exhibition of moral courage hi> 
 inoculation of yellow fever seems unsurpassed. il- i- n..\v a helpless 
 unable to walk, and he is totally disabled for any kind of employment, hi- ailment 
 being rnyel iti-, or disease of spine, and is the result ol up<>n him 
 
 when he volunteered to become a subject for experimental purpo-cs in the yell.iw- 
 iial in Cuba. At tin- lime h" made the Kierifico he was a private in the 
 Hospital Corpn of the Army, in which heenl, L898. \\hen ho was 
 
 finally discharged from the hospital, h<- was app.int'-d an a- tin/ hospital M- 
 served as such until the d.ii<- of his di- 
 
 enlistment he served in Company I), One hundred and fifty-seventh Indiana Volun- 
 teer Infantry, from April 2", 1898, to Noven i i .ni: enli.-ted in 
 at the breaking out of the war with Spain, and in response to President Me Kin ley a 
 call for troops. 
 
 The commission that investigated the mosquito theory oi llou 
 
 fever in the fall of 1900 was composed of Dre. Walter i;.-'d, James Carroll, and Jesse 
 W. Lazear. From a book entitled "Walter k--d and V- II ' Howard 
 
 A. Kelly, professor of surgery of the Johns 1 i 'Diversity, published in New 
 
YELLOW FEVER. 31 
 
 York by McClure, Phillips & Co., on page 139, is the following paragraph in regard 
 to this soldier: 
 
 humanity and the cause of science. ' When it became known among 
 troops that subjects were needed for experimental purposes, Kissinger, in company 
 with another young private named John J. Moran, also from Ohio, volunteered their 
 services. Dr. Reed talked the matter over with them, explaining fully the danger 
 and suffering involved in the experiment should it be successful, and then, seeing they 
 were determined, he stated that a definite money compensation would be made them. 
 Both young men declined to accept it, making it, indeed their sole stipulation that 
 they should receive no pecuniary reward, whereupon Maj. Reed touched his cap, 
 saying respectfully, 'Gentlemen, I salute you.' Reed's own words in his published 
 account of the experiment on Kissinger are: 'In my opinion this exhibition of moral 
 courage has never been surpassed in the annals of the Army of the United States.'" 
 
 Dr. Lazear died of yellow fever in Cuba at that time. Dr. Carroll died later of 
 disease resulting from yellow fever contracted during his experiments with that 
 trouble. Dr. Walter Reed is also dead, and the widows of these three men have all 
 been remembered by the Government in an annuity of $125 per month. On account 
 of the death of these doctors, soldier is unable, of course, to furnish any further evi- 
 dence from them, but his volunteer submission to inoculation from infected mosqui- 
 toes is a matter of record in the archives of the War Department. 
 
 He is now receiving a pension of but $12 per month, and he can obtain no further 
 relief because he is unable to furnish direct testimony tracing his present grievous 
 condition back to yellow fever in the Army, although there is but little doubt that 
 the relation of the cause and effect exists. Since his discharge he has never been in 
 good health, which he at first attributed to slow recovery from that disease, thinking 
 that with the passing of time his constitution would enable him to throw it off. He 
 continued to fail, however, and is now -a helpless paralytic. In the meantime he 
 had married, and is now supported by his small pension and laundry work done by 
 his wife and contributions to his support by a few people who appreciated his services 
 to humanity. 
 
 A bill to grant him a pension of $30 per month passed the House during the session 
 of the Fifty-ninth Congress, but by mistake the rate was cut to $12 per month, at 
 which amount it was finally approved. In his present helpless condition it is believed 
 that he is entitled to a highly substantial measure of relief, his disability seemingly 
 being due to causes of service origin. 
 
 In view of the fact that a pension or annuity of $125 per month was granted to the 
 widows of Drs. Lazear and Carroll, who conducted these experiments with yellow- 
 fever infected mosquitoes, and who died as a result of being infected by mosquitoes, 
 your committee are of the opinion that as great consideration should be given to the 
 man who braved the danger and who, while he escaped with his life, is so helplessly 
 crippled that he is unable to do anything to care for himself, as to the widows of Drs. 
 Lazear and Carroll. Your committee therefore recommend in this case a pension 
 or annuity of $125 per month. 
 
 The bill went to the House and was referred to the Committee on Pensions. There 
 the paragraph increasing the pension to the applicant herein was objected to as carry- 
 ing a rate in excess of that allowed to any other private soldier and, regarded simply as 
 a pension and without distinguishing language, establishing a vexing precedent. , 
 
 The facts in this case are exceptional and extraordinary. To meet the exceptional 
 case and obviate the objections the pending bill recites the peculiar circumstances 
 that distinguish the case and proposes an annuity of $125 per month, payable by the 
 Secretary of War in the same manner as the same allowances are now paid to the 
 widows of Drs. Carroll and Lazear. In view of the unprecedented facts in the case 
 and the extraordianry services rendered by the soldier, your committee believe he 
 should receive the same recognition accorded the widows heretofore mentioned. The 
 bill is therefore reported back favorably with a recommendation that it pass. 
 
u 5. 
 IN MEMORIAM. 
 
 DR. WALTER REED, MA.IMI: AND M I:<;K<>\. i \riT.I) STATES AltMV. 
 
 Whereas the Medical Society of the District 'f Columbia has sus- 
 tained an irretrievable loss by the death of Walter Kced, who died 
 at 2 p. m., November 2::. from appendicitis, for which an oper- 
 
 ation had been performed H\e d 
 
 Beitresokeds That in the death of Dr. Reed, the medical society 
 has lost one of its mo<t di-tinLruishcd member i best efforts 
 
 were always at its di-po-al and upon whom it had learned to rely as 
 an able, calm, and accurate exponent of scientific medicine. 
 
 Maj. Reed was born in Glou. County, Va., Sepiem 
 
 1851, and was a graduate of the medical depart mont of tho t'nivt'isity 
 of ^'irlrinia, 1869, and Bollcvno Jlosnital M-di.-al C..HCL II.' 
 
 was appointed assistant surgeon, rintrd States Anny,.hine 26, 1 B75j 
 promoted assistant snrroon, with (he rank of captain, June 26, 1880; 
 surgeon, with rank of major, December 4, IS'.):-;, and at the time of his 
 death was first on the list of majors in the Medical Department. 
 
 He served with distinction as medical officer at various Armv 
 posts in the Far West, and as his skill and devotion extended to hotli 
 officers and enlisted men alike, he endeared himself to all claac 
 the command. 
 
 During his service at Fort McHenry, Md., in 1881, and again while 
 
 nding surgeon and examiner of recruits at Ba! 
 October, 1 890, to October, 1891, he made special stud ie> in bac 
 and pathology at the Johns Hopkins Hospital, and alter u to 
 service at Fort Snellmg and St. Paul, he was >ele< i, ,1 !,\ the 
 Greneral, in August, 1893, as curator of the Army Medical Mu 
 where he continued his studies which ultimately secured for him fa mo 
 and distinction. 
 
 During the Spanish-American War he was president of the board 
 of medical officers to investigate and report on the ji; \alen 
 typhoid fever in the Army, and the commission, strongly inmr- 
 with the agency of flies as carriers of this disease, recommended the 
 collection of excreta in galvanixod-iron tanks, which method was 
 adopted and was followed by a cessation of the disease. 
 
 His greatest achievement for science and humanity was his con- 
 tribution to the cause, spread . and prevention of \ ellnw f. 
 ing from Finlav's theory of the a-. n< y of the nioxpiiio in the dis- 
 semination of tnis disease, the coin mission of which Dr. Kecd was the 
 head made a series of pain-ta i.eriments and demonstrated 
 
 conclusively the causal relation of Stegomyia^asciata to yellow i 
 epidemics and disproved the theory that the disease could oe conveyed 
 mfomites, or that it vraa oontagtatu in the ordinary acceptation of the 
 term. 
 
 * The preamble and resolution ware adopted December 3, 1902. 
 
YELLOW FEVER. 33 
 
 The practical value of this discovery, which in point of importance 
 and far-reaching beneficence ranks only second to Jenner's discovery 
 of vaccination, has been proved by the complete eradication of this 
 scourge from Habana. 
 
 Maj. Reed has demonstrated how to rid the world of yellow fever, 
 but his studies as to the etiology of the disease were interrupted by 
 his untimely death; he had, however, arrived at the conclusion that 
 the disease was not due to Sanarelli's Bacillus icteroides, but was 
 probably caused by some ultramicroscopic organism. Dr. Reed was 
 a clear, forceful writer and speaker; all of his facts were collected with 
 the utmost care and presented in a concise, logical, and convincing 
 manner, and his crowning work shows the highest degree of scientific 
 accuracy, combined with calm judgment and discrimination, qualities 
 which are not only of the utmost importance in searching the causes 
 of epidemic diseases and tracing their progress, but which would have 
 also fitted him for the highest position in his corps. 
 
 In every sphere of activity, whether as a medical officer, author, 
 teacher, or investigator, he has acquired a distinction which rightly 
 places him in the first rank of illustrious American physicians. 
 His labors in behalf of science and humanity have been recognized 
 by Harvard, Ann Arbor, and the American Medical Association, 
 and he has borne his Honors with accustomed modesty and innate 
 dignity. Dr. Reed was singularly free from all mean self-interest 
 and ambition, and was ever ready to give full credit to his col- 
 leagues for their share of the work which made him famous. We 
 have simply to recall his glowing tribute to that brave young soldier 
 Kissinger, from Ohio, who on December 5, 1900, was the first to 
 volunteer to be bitten by infected mosquitoes, with the only provision 
 that he should receive no pecuniary reward, since as he expressed it, 
 he was actuated "solely in the interest o'f humanity and the cause of 
 science. " Such exhibition of moral courage, in the opinion of Dr. 
 Reed, has never been surpassed in the annals of rhe Army of_tie 
 United Stales, and we will add, could never have been inspired except 
 by a man of Dr. Reed's greatness. 
 
 "His lips are silent; no longer will the sound of his musical but 
 decisive voice be heard within these walls, nor his personal mag- 
 netism and discerning mind delight, instruct, and charm his listen- 
 ers, but his deeds will live and his example will be an inspiration 
 to the present and future generations. 
 
 Dr. Reed's death in the prime of life, in the zenith of his dis- 
 tinguished career, is a severe blow to scientific medicine, his corps, 
 and the medical profession which he adorned. This society, while 
 expressing the sincerest grief at the loss of our distinguished associate, 
 whose personal qualities commanded our highest friendship and 
 respect, is not unmindful of the irreparable loss sustained by his 
 beloved family, to whom we beg to offer our heartfelt sympathy in 
 the hour of their great affliction, united with the fervent hope that 
 a grateful Nation will recognize the economic value of. Dr. Reed's 
 discovery and make adequate provision for those who were dependent 
 upon him for support. 
 
 GEO. M. KOBER, 
 D. K. SHUTE, 
 F. S. NASH, 
 
 Committee. 
 79965 S. Doc. 822, 61-3 3 
 
34 Yri.I.OW l-T.YKR. 
 
 MEMORIAL MEETING OP THB MEDU v OF THE DISTRICT OP COLUMBIA, nn n 
 
 DECEMBER 31, 1902. 
 
 INTRODUCTORY ADDRESS BT SAMUEL 8. ADAMS, A. M., M. D., PRESIDENT 
 
 Ladies and gentlemen: Once more we have been railed together 
 
 to pay tribute to the nuMiiory of an honored colleague, whose counsel 
 we have enjoyed for nearly a leeade. The possessor of a striking 
 personality . unusual reasoning power, an unbiased judgment, ami a 
 determination to enforce his convictions, Dr. Walter Reed could not 
 fail to adorn and stimulate this >cientilic body as well as the inilitary 
 seryiceof the I'nited States Army. The aged die, and we wonder not, 
 believing that they have fulfilled their mission; but when a colaboivr 
 in the prime of life, at the height of his usefulness, is cut down before 
 he has had time to enjoy the full fruition of his labors, we marvel, 
 we are lost in wonder. 
 
 Dr. Keed was elected a "member by invitation" March 11. 1894. 
 The preceding meeting, however, he made his first appearance in 
 society, having been invited to open the discussion on Dr. 
 Kinyoun's paper, entitled "The prevention and control of dinh- 
 theria." In reverting to this debate, we can recall his mo. lest 
 demeanor, his convincing arguments, and his power to hold his audi- 
 ence throughout a lengthy presentation of trie subject. He 1 
 by saying that his clinical experience, laboratory work in inoculating 
 animals, and bacteriological studies had led him to certain ideas as 
 fixed convictions: 
 
 1. The Klebs-Loeffler bacillus is usually characterized by a depM>ii 
 of false membrane in the throat and is attended by frequent 1 
 sequela?. This bacillus he believed to be the cause of true primary 
 diphtheria. 
 
 2. That diphtheria is local in the beginning and by the production 
 of virulent toxins tends to become rapidly constitutional. The bacilli 
 themselves have been found in the internal organs of the human 
 subject, as well as in those of animals. So that we can not any longer 
 say that the bacilli remain local throughout the attack. 
 
 3. Diphtheria is not spread by water and food, except by milk 
 and its products, which are infected in transit u. He strongly advo- 
 cated the bacteriological examination in making the diagnosis. 
 
 Two months later, in discussing tuberculosis, he dwelt upon these 
 two points: "The possibility of the transference of tuberculosis by 
 vaccination; and trie possibility of its transference from mother to 
 child in utero." 
 
 January 9, 1895, in discussing diphtheria and its treatment by its 
 antitoxin, he said he believed the production of antitoxin should be 
 under municipal control and be tested by disinterested parties so as to 
 avoid imposition by unscrupulous men whose desire is gain. He 
 lived to see the enactment of a law to protect this community from 
 spurious viruses. He had witnessed the wonderful iininuni/ing 
 effects of Antitoxin, so advised its use as a preventive as well as a 
 curative agent. 
 
 Ills masterly hand struck the death blow to the opponents of anti- 
 toxin in the discussion of "The clinical aspects of diphtheria treated 
 by its arn December 4, 1895. 
 
 A clinician of wide experience and recognized ability, while dis- 
 claiming any unfriendliness toward its use, had taken a decided stand 
 
YELLOW FEVER. 35 
 
 against this serum, basing his remarks upon the statistics and argu- 
 ments of a distinguished English laryngologist and a well-known 
 American pediatrist. It seemed as if the pendulum were swinging 
 toward the opposition when Walter Reed entered the forum majes- 
 tic, fearless, determined to conquer. With keen eyes fixed on his 
 principal antagonist, he hurled his weapon of defense in unmistakable 
 language, when he said : 
 
 You are theorizing while we are dealing with facts. If another friend of antitoxin 
 
 arises and deals it such blows as Dr. has given it, the antitoxin serum will be 
 
 slaughtered in the house of its friends. 
 
 In concluding his remarks, came this appeal: 
 
 I myself almost feel like saying, with the reader of the paper, that the failure to use 
 it in a case of human diphtheria is criminal; and I beg of you, that if you have not yet 
 done so, when you next stand by the bedside of your patient afflicted with this disease, 
 you do not, through any fear of its peculiar action, withhold this invaluable remedy. 
 
 It must have been a great satisfaction to him to witness not only 
 the conversion of his opponents, but the universal use of the anti- 
 toxin of diphtheria. 
 
 His paper entitled "What credence should be given to the state- 
 ments of those who claim to furnish vaccine lymph free from bac- 
 teria?" is worthy of praise. He conducted a series of experiments 
 upon monkeys by vaccinating them with various vaccine matter, 
 and was " convinced that all virus contained bacteria and that 
 bacteria-free lymph did not exist." 
 
 It is a singular coincidence that the last appearance of Dr. Reed 
 in this society was at a memorial meeting, when he eulogized as 
 an author his friend and associate, Dr. W. W. Johnston. 
 
 The Medical Society of the District of Columbia is proud of hav- 
 ing had the friendship of Walter Reed; we gloried in his achievements, 
 and we now mourn the loss of a courteous, industrious, famous, and 
 highly honored member. 
 
 HISTORICAL REMARKS, BY MEDICAL DIRECTOR R. A. MARMION, UNITED STATES NAVY. 
 
 Mr. President and members of the Medical Society of the District 
 of Columbia: Walter Reed was born in Gloucester County, Va., on 
 the 13th of September, 1851, and was the son of Rev. Lemuel 
 Sutton Reed, who was for 40 years or more an eminent Methodist 
 minister. In his personal appearance Walter was highly favored 
 even in his youth, and to this there were added a gentleness of dis- 
 position and a graciousness of manner which won for him the admira- 
 tion of all who were brought in contact with him qualities which we 
 know were characteristic of him ever after. Intellectually he was, 
 as a boy, precocious and devoted to study, so that at the age of 15 
 he had acquired a knowledge of Latin and Greek rarely found in one 
 so young. History, literature, and philosophy were also favorite 
 studies, and his familiarity with them rendered him the peer of many 
 who were his seniors in age by several years. 
 
 By a special dispensation he was matriculated in the academic de- 
 partment of the University of Virginia at the age of 16. He quickly 
 attained and held, throughout that first year, the highest standing in 
 his classes. Owing, however, to the limited means of his father, who 
 was maintaining two other sons at the same school, it became evident 
 to Walter that he would not be able to carry out his original plan of 
 completing the academic course; so, at the beginning of the following 
 
36 YELLOW FEVER. 
 
 year he began the study of medicine, and at the end of one session of 
 nine months he was awarded the dome of doctor of medicine, although 
 he was not yet 18 years of age. This feat he accomplished in snite 
 of tin' advice of friends who had, in advance, sought to diuade him 
 from undertaking it. His only reply to such advisor- waa that "he 
 did not result." In a few months after his graduation at the 
 
 rniversitv of Virginia he- went to New \ ork and matriculated at the 
 
 BeUevue Medical College, and in one sv- (iiired tl 
 
 M. D. Following his graduation at Bellevue he was attached to 
 various hospitals in New York and Brooklyn, conspicuously the 
 Brooklyn City Hospital and the Charity Hospital on Bftadcwell'fl 
 Island; at t he latter he devoted himself especially to the study of the 
 diseases of women and children. He was also for awhile, one of the 
 the poor of New York City. During his Brooklyn life 
 he had attracted the attention of Dr. Joseph Hut chins* n, one nf the 
 most prominent medical men of that city, who urired and secured his 
 appointment as one of the five inspectors of the board nf healt: 
 position much sought after in those days. This post he was filling 
 most creditably when his twenty-first "birthday dawned. Kven at 
 this early date, Dr. Heed had acquired a very enviable standing 
 among the medical, men of New York and Brooklyn, among whom 
 he was especially well known for his skill as a surgeon. Within . 
 years, as we have seen, he had been holding various professional ; 
 tions of responsibility, but he could not help feeling that there was a 
 point beyond which he could not go on the road toward that sii 
 which he coveted, without the influence of wealthy friends and of in- 
 fluential social connections on the spot. Thus it was that in 187 -1 he 
 began to think seriously of entering the Medical Corps of the Army or 
 of the Navy, and, by the spring of 1875, he had chosen the Army as 
 the field of his future labors. 
 
 I can not dismiss this part of my subject without pausing for a 
 moment to weigh certain characteristics of our lamented colleague 
 and, first of all, I would advert to the fact that even in his 
 hood years there shone forth so many of the splendid traits which 
 illustrated his after life; he was firea with ambition and sustained 
 by an indomitable energy in his early student day- \\hi.h invari- 
 ably brought him victory; but his innate tenderness of nature and 
 his exquisite regard for the sensibilities of a disappointed emit extant 
 so dominated him at such times that no one ever knew him to 1 
 of his victory. A deference for the opinions of others, too, \\ a- a 1 
 a prominent characteristic; and this we have seen rvincrd so uni- 
 formly in the discussions taking place at meetings of this so< 
 And so I might go on analyzing and dwelling upon other tr. 
 but the limited time prevents me. 
 
 Turning to the military history of Maj. Walter Keed. as home 
 upon the records of the office of the Surgeon General of the Army, 
 we find that he was appointed it, surgeon with the rank of 
 
 first lieutenant June 26, 1875; promoted to be a*- Mam 
 with the rank of captain June 26, 1880; surgeon with rank nf major 
 December 4, 1893; and at tin- time of his death was first on the li-t 
 of majors in the Medical Department. 
 
 He was on duty in the Department nf the East from duly '23, 1875, 
 to May 21, 1876; in the Depart merit nf Ari/onu from June, 1876, to 
 May, 1880; again in the Department of the Kast from September, 
 
YELLOW FEVER. 37 
 
 1880, to. November, 1882. From November, 1882, to July, 1887, 
 he was attached to the Department of the Platte, and from August, 
 1887, to October, 1890, he was on duty at Mount Vernon Barracks, 
 Ala. His next assignment was to duty in Baltimore, Md., from 
 October, 1890, to October 1891, when he was transferred to the De- 
 partment of Dakota, where he remained until August, 1893, when he 
 was ordered to duty in the office of the Surgeon General of the Arnry. 
 Under this assignment he was curator of the Army Medical Museum 
 and member of the faculty of the Army Medical School for over nine 
 years and up to the date of his death, which occurred in this city 
 November 23, 1902. 
 
 In the meantime, too, he served, at several different periods, as 
 member of the Army Medical Board in this city, was a member 
 of the cholera board in July, 1898; was on detached duty making 
 inspections of camps and field hospitals in August, 1898; was member 
 of the typhoid fever board in August, September, and October, 1898; 
 in October, 1898, he was on inspection duty at Natural Bridge, Va., 
 and again in April and May, 1899, at Puerto Principe, Cuoa. In 
 March and April, 1900, he was ordered to investigate and report 
 upon the use of electrozone and germicides at Tampa and Habana, 
 and in June and July, 1900, was a member of a board of medical 
 officers at Camp Columbia, Cuba, for the purpose of scientific 
 investigation with reference to infectious diseases prevalent in Cuba, 
 and, from September 27 to October 13, 1900, on similar duty with 
 regard to yellow fever. These various assignments were of great 
 importance from the standpoint of preventive medicine and did 
 much to solidify the foundation on which he was destined to erect 
 the structure "more lasting than brass" which to-day towers above 
 the many works of a life full of labors for the benefit of his fellow 
 man. 
 
 It seems to me that I can not better close this paper than by 
 quoting the language of the official record of Maj. Keed as drawn 
 from the files of the Surgeon General's Office : 
 
 Of Maj. Reed's work in the Medical Department and his scientific researches, it 
 is probable a complete history can never be obtained. His eminence as a bacteri- 
 ologist, and in practical hygiene as applied to military life (as a student of all forms of 
 bacteria) led to his being intrusted with special investigations, which were interrrupted 
 by his death, and which, it is now believed, will never be completed. He was 
 regarded by his associates as a man who combined an unusual degree of scientific 
 accuracy with calm judgment, which rendered him invaluable in searching out the 
 causes of epidemic diseases and tracing their progress. 
 
 In 1901 he began the investigation of the cause and the prevalence of yellow fever, 
 conducting his investigations at Quemados, near Habana, where he established 
 headquarters and was given every facility for conducting his experiments. 
 
 The conditions in Cuba in 1901 were such as made the investigations of Maj. Reed 
 and his corps of assistants of special moment. An epidemic of yellow fever existed 
 despite the efforts of the sanitary experts, led by Gen. Wood, who were endeavoring 
 to stamp out the disease. The houses of persons infected were subjected to rigid 
 disinfection. Furniture was destroyed and every possible precaution was taken to 
 prevent the spread of the disease under the old treatment. Maj. Reed became con- 
 vinced that proper sanitation was not all that was needed. He believed that some 
 other agency than accumulations of filth was responsible for the spread of the disease, 
 and his attention was attracted to the fact that it took much longer for a house to 
 become infected than the usual time of incubation. This suggested a biting insect 
 as an intermediate host of the parasite, and he asked and promptly received from 
 Gen. Wood permission to make experiments with mosquitoes as the conveyers of 
 yellow fever, and a liberal supply of money for these experiments. It was thus 
 determined beyond question, that through a certain species of mosquito the yellow 
 fever germ was disseminated. 
 
38 YELLOW FEVER. 
 
 In recognition of this precious work the degree of master of arts 
 was conferred upon Maj. Reed by the Harvard University in ,June. 
 1902, because, as President Eliot stated when the degree was awarded, 
 Maj. Reed had demonstrated how to rid the world of \ello\\ fever, 
 About the same time the degree of LL. D. was conferred upon him 
 he University of Michigan at Ann Arhor. Midi. 
 
 MAJ. REED A8 A MEDICAL OFFICER, BY MAJ. J. R. KEAN, SURGEON, UNITED 81 
 
 In speaking of Dr. Reed as a medical ofliccr we should consider 
 especially that part of \ii^ career with which the members of this 
 society are least familiar, namely, from his entrain -c into the Army 
 in 1875 to his assignment to duty in Washington in is ( .:;. With 
 the latter date began his career as a scientific man, although mm-h 
 of his time during this la-t decade was given to examining boards 
 and other work of a military rather than scientific character, and the 
 race horse spent much tune at the plow. 
 
 The<e 1 s years of garrison duty were, we may be sure, not wasted, 
 the official records tell but little of them. The records show I "> 
 changes of station (with 4 years in Arizona, 5 in the Department of 
 the Platte, 2 in the Department of Dakota, 3 in the South, and :; in 
 the East). There are a few brief commendations for professionn ! 
 and devotion to his patients, and that is all. 
 
 The work of young Army surgeons claims always little spaee in the 
 gazettes or in the reports of military commanders, and in the seven t ies 
 and eighties the hie was certainly not stimulating to intellectual 
 effort. 
 
 The surgeon shared with his comrades of the line the tedium of 
 long marches and the monotonous sameness of Arizona summers and 
 Dakota winters. And those with whom bonne camaraderie out- 
 weighed studious industry shared also the afternoons of hottlepool 
 and beer and the nightly seductions of draw poker. But for medical 
 officers this life was redeemed by the study of our profession, which 
 was then beginning to broaden out from ancient channels into the 
 full flood of recent progress, and it was saved from triviality l>\ those 
 stern responsibilities of life and death which practice hrin.irs to all 
 physicians. To lesser minds the limitations of such a life niiirht have 
 been narrowing, but for the eager industry and professional d< -\ <>t i,,n 
 of a Reed they made the roots strike deep ; and when we are su ij 
 at the rapid growth and splendid fruit of his career as a scientist we 
 must remember that in the post surgeon's unmarked life the 
 germinated and the roots were firmly set. But for the opportunities 
 given him by his position in the Army, however distinguished he may 
 have become in other ways, it is safe to say that the \\ork \\ith whicn 
 his fame will always be inseparably connected would n< 
 been accomplished bv him. During this lon# apprenticeship he 
 acquired too that perfect familiarity with the conditions and limita- 
 tions of Army life which, combined with his scientific knowledge 
 sound judgment, made him the hot sanitary inspector in the Army 
 and the court of last resort on all sanitary questions. 
 
 I first learned to know Dr. Reed by reputation when in the spring 
 of 1888 I followed him in .station at 'Fort Kol-in-oii. a t \\o-ha 1 1 alion 
 po>t in the northwc-t corner of \ehraska. I learned much of his 
 devotion to his patients, and their devotion to him was equally 
 
YELLOW FEVEE. 39 
 
 in evidence. The country about is thinly settled with families 
 locally known as "Grangers/' who were attempting to support 
 themselves by farming in a grazing country where the rainfall was 
 not sufficient for good crops except only about one year in three. 
 The crop of babies, however, never failed, and the Klebs-Loeffler 
 bacillus and the pneumococcus flourished perennially in their wretched 
 cabins. To Reed's tender and generous spirit the call of these poor 
 people never came in vain, and the trail was never so long or the 
 night so dark as to deter him. In the winter these rides were really 
 dangerous and a source of much uneasiness to his family and friends 
 for fear of his being overtaken by one of those blizzards in which 
 the staunchest horse turns tail to the wind and the most experienced 
 frontiersman can not see his way, and the danger to the lost traveler 
 is greater than that of a battle. 
 
 Again we find him at Mount Vernon Barracks in Alabama, accord- 
 ing to the official statement of his commanding officer, devoting 
 himself with the same earnestness and patience to the sick of Geroni- 
 mo's band of Apaches, then held there as prisoners, and to the sick 
 negroes of the surrounding country, as to his own patients in the 
 garrison. 
 
 Of the first years of his service which he spent in Arizona I gained 
 some knowledge when in the summer of 1896 he came to Key West, 
 my station at that time, to study the blood of variola there being 
 an epidemic of smallpox there at that time. All day he would 
 sit over his microscope, but the evenings we spent on the coolest 
 corner of the porch looking out at the quiet tropical sea, while he 
 told reminiscences, suggested, it may be, by the heat, of his service 
 at Fort Yuma and Camp Apache. These stories were full of that 
 humor which was so characteristic and so pleasing a trait of his 
 daily conversation, and some of these were models of the short 
 story. The history of Sally Ann, a. Gila monster (named after the 
 two ladies of the post most conspicuous in church work), which the 
 chaplain captured in his kitchen, and undertook to tame, would 
 have made a perfect magazine article just as Reed told it. His 
 account of his summer at Yuma, the hottest of Army posts, where 
 the daily July maximum was from 112 to 115, still brings back a 
 clear-cut picture to my memory, and I can see him with his messmate, 
 a captain of infantry, who weighed 250 pounds, and the soldier or 
 in Army parlance "striker" who filled the dual role of chef and 
 butler. The captain, a vertiable Porthos, sat down to dinner in 
 two garments, with a fan, a towel to wipe his face, and near at hand 
 a pitcher of the largest size full of water from the olla, for there 
 was no ice. Before him was a large roast of range beef, which, 
 after helping Reed, he would consume entirely and likewise empty 
 the water pitcher. 
 
 On one occasion Reed took a leave, and, in company with another 
 officer and a lady of the garrison going home, drove in an ambulance 
 150 miles to the railroad. The other officer was charged with the 
 commission of laying in the food for this trip of nearly a week. After 
 they started they found that the provision consisted simply of crack- 
 ers and sardines. Reed up to that time had never been able to eat 
 sardines, but he learned on this trip. He had his share also of Indian 
 campaigning, and on one occasion brought into the post a little Indian 
 girl of 4 or 5, who had been so horribly burned that her people had 
 
40 YELLOW FEVEB. 
 
 abandoned her to die. This child ho succeeded in saving and brought 
 
 :p in his family as a nurse for his children in spite of the warning 
 
 of that keen old Indian lighter, Gen. Crook. When she was i:ro\\n. 
 
 savage Apache blood a it -elf. and she ran 
 
 giving evidence that 15 years of p -ntl -ness and refinement had not 
 modified the cruel and deceitful charaotftf of her race. 
 
 Memory often holds 1110-1 f;iM to trivial things, but they are 
 usually char So. though what has come into my mind to 
 
 tell you of our i nd is not of weighty matters: yet they show 
 
 the "odd id.'s of Army life and show him as he was the 
 
 pleasant comrade, the eager student, and the de\ oted doetnr. gentle, 
 unselli>h, modest, and brave, as the gentle and devoted . 
 
 : this earned spirit and the high purposes of his life played ah. 
 a merry and kindly humor like the dancing lights and reflect* 
 
 -urfaceof a deep, swift river. It was often keen, but tter, 
 
 and was his mo>t striking social characteristic, as was devotion to the 
 duty which was before him the dominant feature of his professional 
 life. For him, as for the great Duke 
 
 The path of duty was the way to glory. 
 
 He that walks it only thirsting 
 
 For the truth, and learns to deaden 
 
 Love of self, before his journey closes 
 
 He shall find the stubborn thistle bursting 
 
 Into gloesy purples, which outredden 
 
 All voluptuous garden roses. 
 
 He that ever follows her commands 
 
 On with toil of heart and knees and hands 
 
 Through the long gorge to the far li.L'ht, has won 
 
 path upward and prevailed. 
 Shall find the toppling crags of duty scaled 
 Are close upon the shining table-lands, 
 To which our God Himself is moon and sun. 
 Such was he his work is don 
 
 DR. WALTER REED AS A TEACHER, BY A. F. A. KINO, A. M., M. I>. 
 
 At the time of the organization of the United States Army Medical 
 School, in 1893, Dr. Reed was appointed pn.fe ..r <f hacteri 
 and clinical microscopy, and he continued to fill this position 
 to perform its duties most acceptably until the time of his decease, 
 in N'ovember, 1902. 
 
 Two years after beginning his work in the Army Medical School 
 he was elected professor of pathology and bacteriology in the medical 
 school of the Columbian University in this city, and he continued to 
 hold this position also until the end of his life. 
 
 If we endeavor to ascertain in a general \\a\ what are the require- 
 ments necessary for anyone to become a really -killed an. I BU 
 instructor in any department of knowledge, and th ourselves 
 
 how far Prof. Heed possessed t hese qualif icat ion-, it \\ill at once he 
 seen that the particular attributes necessary were preeminently his 
 own. 
 
 To teach well one must know well the subject to be taught . and, 
 conversely, he who can not explain a thin-_ r l arly to somebody da- 
 does not usually know it well himself. 
 
 In the whole domain of medi/al science there is probably no 
 subject more dif lie ult and intricate than that of pathology, especially 
 
YELLOW FEVER. 41 
 
 when considered in relation with bacteriology, this latter being also 
 a comparatively new departure, and therefore bristling with the 
 unfamiliar terms of a new and labored nomenclature, as every new 
 science necessarily must be. 
 
 Notwithstanding these difficulties, Prof. Reed, with his well- 
 trained mind and cultivated powers of observation, inspired, too, with 
 the spirit of research and led on by the charm of discovering new 
 principles and new facts, had devoted himself with so much ardor, 
 earnestness, and industry to the study of his chosen sphere of thought 
 that, it may be said, all difficulties had been trampled under his feet; 
 that he rose, step by step, to higher and still higher planes of knowl- 
 edge, until reaching an eminence where the whole subject became 
 easily intelligible in one comprehensive view and where he himself 
 attained a complete mastery of his favorite theme. 
 
 Having traversed the highways of knowledge himself he was 
 fully able to lead his pupils along the same paths and perhaps point 
 out to them many short cuts which were easier than the longer 
 distances and more laborious journeys originally pursued by him- 
 self. It should be remembered also that many of these roads were 
 not always the well-traveled avenues of old lines of thought, but, on 
 the contrary, entirely new, strange, and perhaps lonely ways, far out 
 in the prairies of investigation, where briars of speculation, weeds 
 of error, and the ignes f atui of false theories were liable to obstruct 
 and mislead the honest seeker for truth. It was under these circum- 
 stances that Prof. Reed became a trusted guide and counselor. In 
 these trackless wastes of thought he could not easily get lost or take 
 a wrong direction, for in many instances he was able to say: "I made 
 these paths myself," and he well knew whither they would lead. 
 
 The successful teacher, however, must not only possess the requi- 
 site knowledge and be able to guide his pupils in the best way, and 
 hold out to them the easiest method of obtaining the information for 
 which they are in search, but he should also have the faculty of pre- 
 senting the subject in such a manner as to hold their undivided 
 interest and attention by pointing out the attractive features and 
 pleasing aspects of the subject under discussion. Dreary, indeed, 
 would be the road to learning were it always through thorns, thistles, 
 and briars, with no flowers to charm and no vistas in the forest 
 through which we might at times obtain a glimpse of pleasant scenes 
 of sunshine and beauty. Dreary, and dull too, will be the teacher 
 who continues his endless monotony of tiresome propositions, with 
 no touch of humor and no sparkle of wit to vary the irksomeness of 
 continued effort and awaken the flagging power of a strained atten- 
 tion by the pleasant diversion of an occasional happy thought. 
 
 In this particular again Dr. Reed was singularly fortunate. One 
 of his latest admiring pupils writes me that 
 
 his lectures, besides satisfying the zealous seeker for knowledge, were spiced with 
 humor which was most refreshing, and which made the relation between himself 
 and his students a freer and more sympathetic one. Donnally. 
 
 Indeed, in whatever aspect we review Dr. Reed's work as a teacher 
 and however critically we single out the several qualifications required 
 for the best and most successful execution of the teaching art, we 
 find Prof. Reed happily endowed in a more than usual degree with 
 these special gifts and qualifications, and which he knew full well 
 how to utilize to the best advantage. 
 
42 YELl.ou 
 
 During the later years <>f Prof. Reed's work in the medical school 
 of the Columbian University he was assisted by Dr. James Carroll, of 
 the I n it ed States Army, who also accompanied l>r. Reed t. llabana, 
 and again assisted him in their well-known experiments with mos- 
 quitoes and yellow fever. No one, perhaps, was better acquainted 
 with Dr. Reed's methods of teaching than Dr. Carroll, who kindly 
 writes me as follows: 
 
 Dr. Walter Reed was respected and beloved by all his pupils. Always kind and 
 courteous, earnest and enthusiastic, he imbued them with the same spirit . and i 
 .it'lv commanded their respect and attention. A thorough nutter pi his nul.jr.-t and 
 of tne English language, he treated the driest and most difficult t<>pi< s in HK h a man- 
 ner as to rvnder t h.-in lucid and interesting. His marvelous accuracy and clear 
 
 v detail, his charming personality and polished manner, made him an 
 ideal professor, of whom his ftnde nts were both fond and proud. ( >f nervous trmprra- 
 ment, he was quick to note and resent the slightest laxity and inattention; and \\ln-n 
 it became necessary to administer a rebuke it was implied rather lhan LM\ en dim 1 1\ , 
 his delica< :.g prompting him to soften the blow by a subtle flash of \\ it that 
 
 convulsed the class and diverted attention from the culprit. The lesson was i 
 forgotten by him for whom it was intended, and it was never necessary to repeat it, 
 
 moral effect of the slightest manifestation of his displeasure was far pr 
 could have been the dread of any other method of reproof. So closely was h in 
 pa thy with his class and so securely had he engrafted nimself upon their affe< t ion 
 their inquiries during his illness and manifestations of grief upon his demise ind 
 the loss of a dear friend, guide, and counselor rather than a teacher of cold scieuti tic- 
 facts. 
 
 Another pupil, Capt. J. Hamilton Stone, assistant surgeon, United 
 States Army, writes me as follov 
 
 As a teacher Dr. Reed always seemed to me to be, first of all, master of his t V 
 His information was so much his own a part of him, as it were that when i 
 given to others it flowed forth with unadulterated naturalness, and sparkled with a 
 Keen interest which his charming personality could not help but lend it. 
 qualities would not permit his words to fall upon deaf ears. His kindly and consid- 
 erate mien, together with his universally acknowledged high scientific attainments, 
 won for him both the respect and admiration of his students. His language was always 
 interesting, eloquent, and well appointed. When at his best his voice would reach a 
 high falsetto note, and this was his characteristic method of impressing importai. 
 upon dull or indurate intellects. His students never feared niin, but from th- 
 regarded him with filial affection. Of patience, that special attribute of a good teacher, 
 he possessed an abundance. He was constantly at the side of his pupil in th 
 oratory, advising, consoling, encouraging, and, above all, instructing. 
 
 A student of the Columbian University, Mr. H. H. Donnally, 
 remarks that 
 
 Dr. Reed's lectures were models of order and system. A recital of the various \ 
 previously held in the different branches of pathology and bacteriology always led up 
 to and served to emphasize the more recent and generally accepted theories. 1 1 
 historic reviews the student was constantly surprised at Dr. Ret kalde 
 
 memory for dates and his familiarity with the host of investigators and tl: 
 special lines of research, not only those in this country, but others in all parts >f the 
 civilized world. This method of unfolding the subject historically, with a final and 
 forcible exposition of the latest current views, was keenly appreciated by the stu 
 and gave them a broad and comprehensive picture of the whole subject, which was 
 easily remembered and understood. 
 
 Finally, I must express my great regret that it has seldom fallen 
 to my lot to hear Dr. Reed lecture, and I have never witnessed his 
 demonstratioDfl in the laboratory; hence I have supplemented my 
 own remarks by quoting from others who had happily been nmn- 
 favored in these respects, and certainly no statements of mine could 
 more appropriately represent the wmk <>f Pnd. K<<d as a teacher 
 than these eloquent expressions from his own faithful and loving 
 pupils. 
 
YELLOW FEVEE. 43 
 
 DR. WALTER REED AS AN AUTHOR, BY CH. WARDELL STILES, PH. D., ZOOLOGIST, 
 UNITED STATES PUBLIC HEALTH AND MARINE-HOSPITAL SERVICE. 
 
 Zoology was once facetiously defined as "The study of the useless." 
 This definition will doubtless appeal to many people as quite appli- 
 cable ; for to persons not in scientific work the practical application 
 of long, detailed, and often tedious accounts of animals is not always 
 evident. In defending such work, many men quote the time-honored 
 expression " Knowledge for knowledge's sake." But seeing little 
 difference in principle between this expression and the phrase " Money 
 for money's sake," and not wishing to pose as a defender of the 
 intellectual miser, I take great pleasure as a professional zoologist in 
 acknowledging the debt which zoology owes to the medical profession 
 for the practical application of zoologic knowledge to the (benefit of 
 mankind. 
 
 Zoologists have shown how important the insects are from an 
 economic standpoint in making or destroying certain foods upon 
 which we directly or indirectly depend for life. But it is chiefly to 
 the medical profession that this world is indebted for the application 
 of entomologic knowledge in connection with the transmission of the 
 important infectious diseases, hence in connection with saving life. 
 
 Dr. Walter Reed, in whose memory we meet here this evening, 
 stands out among medical authors as one who has been particu- 
 larly prominent in this field of work, and though he was not a zoolo- 
 gist by training, his writings in applied zoology in connection with 
 yellow fever entitle him to rank as among the greatest of applied 
 zoologists. 
 
 It was the United States Bureau of Animal Industry which first 
 clearly demonstrated the great importance of arthropods as interme- 
 diate hosts of epidemic diseases, and its reports on the tick (Boophi- 
 lus) as a transmitter of Texas fever of cattle will always remain classic. 
 Then the writings of two English physicians, Ross and Manson, 
 and of an Italian zoologist, Grassi, carried the subject further in 
 connection with mosquitoes and malaria. 
 
 Finally, the writings of our friend Walter Reed and of his asso- 
 ciates demonstrated to us the relation of mosquitoes and yellow 
 fever and showed us how we could protect both life and commerce 
 from this scourge. 
 
 It is interesting to note that all three of these discoveries in applied 
 zoology show certain parallels. All deal with diseases which are 
 preeminently tropical or subtropical; all deal with diseases of 
 unusual economic importance; and the actual positive experimental 
 work upon transmission has been done chiefly by English-speaking 
 investigators. 
 
 Might I add here, without misinterpretation, that the Texas fever 
 work was done before the days of the Noble prize. The first medical 
 awards of this prize of $40,000 were to Behring in recognition of 
 his work for mankind in connection with diphtheria, and to Pawlow 
 for his work in physiology ; the next award was to Ross in recognition 
 of his work for humanity in connection with malaria. Are not Reed, 
 Carroll, Lazear, and Agramonte the natural candidates for the next 
 award because of their work for mankind in connection with yellow 
 fever, and in case the conditions of the grant permit it, should not 
 each of the widows of two of these men receive the share which 
 would have gone to her husband ? 
 
44 YELLOW FEVER. 
 
 DT friend. Dr. Reed, was not what would be railed a prolific 
 
 writrr. His numerous routine duties prevented him from fnrnish- 
 
 ini: the manuscript which we had a right to expect from a man of 
 
 1. beside short n marks in society discussions, his 
 
 bibEography contains 27 original articles all printed between iv.rj 
 
 and lOOl* 'Ten of these articles dealt \\itll Yellow fever, three Mi- 
 four with tvphoid, tuo eaeh \\iih malaria and erysipelas, and one 
 with cholera, pneumonia, trikresol, vaccine, artilicial immunity 
 agair ination. anurhoid b.ulies in the blood of vaccinated 
 
 monkeys and children and in variola, formaldehyde, snlenic leukemia. 
 and -lie. All were in English, and although they were all 
 
 rnment work, it is a striking fact that onl\ > far 
 
 as I have been able to find, wen* pul>li>h<-d by the Government. 
 
 irarding the reneral style of the articles, there are three points 
 in particular which are striking: Kir-t. the attenti..n Driven to details 
 immediately reminds us of the writings of Dr. Theobald Smith of 
 Harvard I : <m<l, the directness of diction immediately 
 
 reminds us of Dr. J. McKeen Cattell, professor of experimental 
 Columbia University. In fact, one of the characteristics 
 . hieh Dr. lie. M! was note<l amonu: his friends was the absolutely 
 straight line of his thoughts and the orderly, lucid, and logical devel- 
 opment of his subject. Third, Dr. Ixeed was of a judicial teni; 
 ment, and the judicial manner in which he handled his subject, even 
 in controversy, forcibly reminds us of the same prominent character- 
 in Prof. William II. Welch of Johns Hopkins Vnivi -r-ii 
 In forecasting the time of the influence of Dr. Reed's writ in^s. it is 
 clear that his articles on yellow fever will far outlive his papers on 
 other subjects. His other writings will be known to men only in 
 iin lines of medical work, but his papers on yellow fever will be 
 known directly or indirectly to both physicians and zoologists, and to 
 both professional men and business men. They will be quoted for 
 decades to come, both by Government officials and by private practi- 
 tioners, and they will be one of the most important factors in deter- 
 mining the future policy of civilized nations in dealing with yellow 
 fever, a disease which w r e dreaded only a few years ago, but now one 
 which, thanks to the work of Reed and bis colleagues, will soon be 
 little more than a medical curiosity. 
 
 BlIH.IOGRAPHY. 
 REED, WALTKU. [1851-1902.] 
 
 1892. The contagiousness of er>> : '.MSI. in M. & S. .1 , \. iL'ti do], M ;ir < h in. 
 
 p. 237. 
 
 1893. Remarks on the cholera spirillum. [An address before Ramsey <'..nnty 
 Medical Society, March 28.] Northwest. Lancet, St. Paul (297), v. 13 (9), May 1, 
 pp. 161-164. 
 
 1894a. Association of Proteus vulgaris with Diplococcus lanceolatus in a case of 
 croupous pneumonia. Johns Hopkins Hosp. Hull., Baltimore, v. 5 (34), March, pp. 
 
 _M n 
 
 1894b. The gennicidal value of trikresol. St. Louis M. <fc S. J. (642), v. 66 (6), 
 June, pp. 329-337. 
 
 1894c.Idem. Proc. Am. Mil. Surg. U. S. (Washington), St. Louis, v. 4, pp. 109- 
 206. 
 
 1894d. A briof contribution to th- i(lcnti(i'-:tii..n ,f Stn-j.i..<-oc<-uH erysipelatoe. 
 Boston M. & S ! (14), Octx.l.-r 1. pp. 339-340. 
 
 1895a. An investigation in to the so-call-<l lymphuM oodulea of the liver ill typhoid 
 fever. Johns Hopkins Hosp. Rep., Baltimore, v. 5, pp. 379-396. 
 
YELLOW FEVEK. 45 
 
 1895b. An investigation into the so-called lymphoid nodules of the liver in ab- 
 dominal typhus. Am. J. M. Sc., Philadelphia, n. s., v. 110, pp. 543-559. 
 
 1895c. What credence should be given to the statements of those who claim to 
 furnish vaccine lymph free of bacteria? [Read before the District of Columbia Med. 
 Soc., June 5.] J. Pract. M., N. Y., v. 5 (12), July, pp. 532-534. 
 
 1896a. [The character, prevalence, and probable causation of the malarial fevers 
 at Washington Barracks and Fort Myer.] Rep. Surg. Gen. Army, Wash., pp. 65-77, 
 1 diagram, 1 table. 
 
 1896b. The parasite of malaria. J. Pract. M., N. Y., v. 6 (9), Apr., pp. 382-383. 
 
 1897a. Serum diagnosis in typhoid fever. Rep. Surg. Gen. Army, Wash., pp. 
 68-73. 
 
 1897b. On the appearance of certain amoeboid bodies in the blood of vaccinated 
 monkeys (Rhoesus) and children, and in the blood of variola. An experimental study. 
 Tr. Ass. Am. Physicians, Phila., v. 12, pp. 291-302, 2 pis. 
 
 1897c. On the appearance of certain amoeboid bodies in the blood of vaccinated 
 monkeys (Rhoesus) and children, and in the blood from cases of variola. An experi- 
 mental study. J. Exper. M., N. Y., y. 2 (5), Sept., pp. 515-527, pis. 38-40. 
 
 1897d. Typhoid fever in the District of Columbia; diagnosis: The value of Widal's 
 test, the dried blood method. Nat. M. Rev., Wash., v. 7 (6), Nov., pp. 144-146. 
 
 1897e. [Experiments with Hollister's formaldehyde generator.] Rep. Surg. Gen. 
 Army, Wash., pp. 103-104. 
 
 1898. Splenic leukaemia. [Trans. Med. Soc. District of Columbia, Oct. 27, 1897.] 
 Nat. M. Rev., Wash., v. 7 (9), Feb., pp. 265-266. 
 
 1900. Report on the practical use of electrozone as a disinfectant in the city of 
 Havana, Cuba. Rep. Surg. Gen. Army, Wash., pp. 178-186. [MS., dated Apr. 20.] 
 
 1901a. The propagation of yellow fever; observations based on recent researches. 
 [Address before 103d Ann. Meeting Med. andChir. Fac., State of Md., Bait., Ap. 24-27.] 
 Med. Rec., N. Y. (1605), v. 60 (6), Aug. 10, pp. 201-209, tables 1, 2. 
 
 1901b. Idem. Rep. Surg. Gen. Army, Wash., pp. 187-202, 1 pi., 6 fever charts. 
 
 1902. Recent researches concerning the etiology, propagation, and prevention of 
 yellow fever, by the United States Army Commission. J. Hyg., Cambridge, Eng., 
 v. 2 (2), Apr. 1, pp. 101-119, charts 1-3. 
 
 REED, WALTER, AND CARROLL, JAMES. 
 
 1899a. Bacillus icteroides and Bacillus cholerae suis. A preliminary note. Med. 
 News, N. Y., v. 74 (17), Apr. 29, pp. 513-514. 
 
 1899b. The specific cause of yellow fever. A reply to Dr. G. Sanarelli. Med. 
 News, N. Y., v. 75 (11), Sept. 9, pp. 321-329. 
 
 1900. A comparative study of the biological characters and pathogenesis of Bacillus 
 X (Sternberg), Bacillus icteroides (Sanarelli), and the hog-cholera bacillus (Salmon 
 and Smith). [Received for publication Feb. 25.] J. Exper. M. [Bait.], v. 5 (3), 
 Dec. 15, pp. 215-270, figs, a-o, pi. 19, figs. 1-3. 
 
 1901. The prevention of yellow fever. [Read at 29th Ann. Meeting, Am. Pub. 
 Health Ass., Buffalo, Sept. 16-21.] Med. Rec., N. Y. (1616), v. 60 (17), Oct. 26, 
 pp. 641-649, figs. 1-10. 
 
 1902. The etiology of yellow fever. A supplemental note. [Read at 3d Ann. 
 Meeting, Soc. Am. Bacteriologists, Chicago, Dec. 31, 1901, and Jan. 1, 1902.] Am. 
 Med., Phila., v. 3 (8), Feb. 22, pp. 301-305, charts 1-6. 
 
 REED, WALTER; CARROLL, JAMES; AND AGRAMONTE, ARISTIDES. 
 
 1901a. The etiology of yellow fever. An additional note. [Read at Pan-Am. Med. 
 Cong., Havana, Cuba, Feb. 4-7.] J. Am. Med. Ass., Chicago, v. 36 (7), Feb. 16, 
 pp. 431-440, charts 1-6. 
 
 1901b. Experimental yellow fever. Am. Med., Phila., v. 2 (1), July 6, pp. 15-23, 
 charts 1-8, tables 1-2. 
 
 REED, WALTER; CARROLL, JAMES; AGRAMONTE, ARISTIDES; AND LAZEAR, JESSE w. 
 
 1900. The etiology of yellow fever. A preliminary note. [Read at Meeting of 
 Am. Pub. Health Ass., Indianapolis, Ind., Oct. 22-26.] Phila. M. J. (148), v. 6 (17), 
 Oct. 27, pp. 790-796, tables 1-3, charts 1-2. 
 
 REED, WALTER, AND STERNBERG, GEORGE M. 
 
 1895. Report of immunity against vaccination conferred upon the monkey by the 
 use of the serum of the vaccinated calf and monkey. Tr. Ass. Am. Physicians, Phila., 
 v. 10, pp. 57-69. 
 
46 YELLOW FEVER. 
 
 DR. REED'S WORK IN CUBA, BY MAJ. GEN. LEONARD WOOD, UNITED STATES ARMY. 
 
 [Abttnot] 
 
 The work of Dr. Walter Reed is the most important work in tho 
 way of medical research and discovery which has been accomplished 
 by any one who has lived in this hemisphere. There is no other 
 medical discovery to which it can he compared, unless it be that of 
 anesthesia. The results to humanity are incalculable and fai reach- 
 ing. It is safe to say that this discovery has resulted in saving each 
 year more lives than were lost in the war with Spain, and in a saving 
 to commerce, and especially to the southern portion of our count rv. 
 of an amount equal to the cost of the war with Spain. 
 
 The following letters and telegrams were received: 
 
 WASHINGTON, D. C., December 29, 1902. 
 Dr. S. S. ADAMS, 
 
 President District Medical Society. 
 MY DEAR DR. ADAMS: I regret exceedingly that an engagement made some time 
 
 and from which I can not excuse myself, will prevent me from att 
 Reed memorial meeting on Wednesday evening. 
 
 No one appreciates more deeply than I do the loss to scientific medicine and to the 
 medical corps of the army caused by Maj. Reed's death. His scientific work was 
 eminently fruitful and far-reaching in its results. As the head of the medical corps 
 during nine years of his most useful work, which was prosecuted under my g< 
 direction, I am of course entirely familiar with the results accomplish 
 
 Maj. Reed was endowed by nature and bv training with the essential qualiti* 
 for engaging in research work in the special field to which he devoted his tal< r : 
 his energies. Conservative, painstaking, thorough, persevering, and ready in ro< 
 he acquitted himself with credit in every task assigned to him, and "ha- 
 great and deserved distinction by his successful demonstration of the method by which 
 yellow fever is transmitted from man to man. In addition to this, he was a modest 
 and courteous gentleman, who attracted all of those who came in contact with him. 
 His death came to me, as to his other numerous friends, as a great persona 1 
 irreparable loss. 
 
 Very truly, yours, GEO. M. STERNBERG. 
 
 BALTIMORE, December 30, 190f. 
 
 DEAR DR. ADAMS: I have to leave unexpectedly to-day for Canada. Please 
 express my regrets that I can not be at the memorial meeting to Reed. 
 With kind regards, sincerely yours, 
 
 WM. OSLER. 
 
 RICHMOND, VA., December SI, 190f . 
 Maj. J. R. KEAN, 
 
 Surgeon General's Office, War Department, Washington, D. C.: 
 Greatly regret I can not attend the meeting to-night in honor of Dr. Hood, whose 
 friendship I prized, whose character I admired, and whose contribution to science and 
 country can not be measured. 
 
 HUGH LEE. 
 
 TREASURY DEPARTMEN 
 PUBLIC HEALTH AND MARINE-HOSPIT ICE, 
 
 Washington, D. C., January 5, 1903. 
 Dr. F. S. NABH, 
 
 17t3 Q Street, Washington, D. C. 
 
 MY DEAR DR. NABH: As you may know by this time, I have been absent from the 
 city for a month and returned Saturday. On opening my mail to-day I find your 
 note of December 9, and I wish to express my great regret that I could not have been 
 here to accept the honor which was conferred upon me of responding at a meeting 
 held in memory of Dr. Reed . It would have been a great privilege to have taken pan 
 
YELLOW FEVER. 47 
 
 in that meeting, and of all the things which I have missed by being away one month 
 I regret this more than any other. 
 
 I had, during his life, the highest regard for Dr. Reed as a scientist, and, more than 
 that, I had the warmest feeling of frienship toward him, although we were by no means 
 intimate, and certinly his death was a blow to science and the whole governmental 
 service. 
 
 I had a conviction that in the near future the service of which I have charge would 
 find a way of having some official connection with Dr. Reed in his great work, and that 
 through him the bond of union between the medical services of the Government 
 would be materially strengthened. 
 
 I have learned that Dr. Stiles took the place which was intended for myself, and 
 I am much gratified that he did. 
 Very sincerely yours, 
 
 WALTER WYMAN. 
 
CHAI-TK.K 6. 
 
 VALUE OF DR. REED'S WORK AND EXPRESSION OF APPRE- 
 CIATION.' 
 
 Popular appreciation of the value of the work of the Yellow Fever 
 Commission has been singularly alow and impeilVrt. While nearlv 
 y educated person in the United States is lamiliar with the name 
 and \\cik of a distinguished Austrian surgeon who has recently 
 demonstrated in this country an operation for the cure of a rather 
 rare deformity in children, only a small fraction of them knew any- 
 thing of Walter Reed, the conqueror of i low pL And 
 yet distinguished men have not been silent in regard to him. < 
 Leonard Wood said, in a recent address at a memorial meeting of 
 scientific men held in honor of his memory in Washington: 
 
 I know of no other man on this side of the world who has done so mucli fur Immunity 
 as Dr. Reed. His discovery results in the saving of more lives annually than 
 lost in the Cuban war, and saves the commercial interests of the world a greater 
 financial loss each year than the cost of the Cuban war. He came to Cuba at ;. 
 when one-third of the officers of my staff died of yellow fever, and we were dis- 
 couraged at the failure of our efforts to control the disease. In th m< 
 the disease was ordinarily worst the disease was checked and driven ir -in II 
 That was the first time in nearly 200 years that the city had been rid 'f it. The 
 value of his discovery can not be appreciated by persons who are not familiar with 
 the conditions of tropical countries. Hereafter it will never be possible for yellow 
 fever to gain such headway that quarantine will exist from the mouth of the Poto- 
 mac to the mouth of the Rio Grande. Future generations will appreciate fully tin- 
 value of Dr. Reed's services. His was the originating, diroctinir. and controlling 
 mind in this work, and the others were assistants only. 
 
 In a letter dated November 24 General Wood said : 
 
 To Maj. Reed belongs the honor of having led in the greatest medical work of modern 
 times, and the results he accomplished will live for all time. 
 
 Prof. William H. Welch, of Johns Hopkins, said in a letter to the 
 Secretary of War: 
 
 Dr. Reed's researches in yellow fever are by far the most important contributions 
 to science which have ever come from an Army surgeon. In my judgment, th< 
 the most valuable contributions to medicine and public hygiene which have 
 been made in this country with the exception of the discovery of anaesthesia. 1 
 have led and will lead to the saving of untold thousands of lives. I am in a p<> 
 to know that the credit for the original ideas embodied in this work belongs wholly 
 to Maj. Reed. Such work, if done in Europe, would receive substantial recopi 
 from the Government. 
 
 He was last year given the degree of LL. D. bv the University of 
 
 Michigan, and the degree of M. A. by Harvard University. In ('-nn- 
 f erring, the language used by President Eliot was: 
 
 Walter Heed, graduate of medicine of the University of Virginia, the Army surgeon 
 who planned and dirc< ted in Cuba the experiments which have given man control 
 over that fearful scourge, yellow fo\ 
 
 i "The scientific work and discoveries of the late Maj. Walter Reed. ' s Array" (8. Doc. 
 
 Mo. 11B, Jan. 28, 1003), ordered to be published. Prepared by Maj. Jefferson K. Kean. 
 
 48 
 
YELLOW FEVEE. 49 
 
 Precedents are abundant for State aid to public benefactors and 
 their families. The English Government a century ago, when the 
 purchasing value of money was far greater than at present, gave to 
 Jenner, the discoverer of vaccination, grants amounting to 30,000. 
 He also received 7,383 from a subscription in India. 
 
 Pasteur, the founder of the science of bacteriology, besides numer- 
 ous honors and decorations and money donations from other sources, 
 received from the French Government a pension of 12,000 francs. 
 
 Lister, the originator of antiseptic surgery, has, besides numerous 
 honors and decorations, been successively knighted and elevated to 
 the peerage. 
 
 In this country a bill to donate $100,000 to the discoverer of anaes- 
 thesia was twice passed by the Senate (in 1853 and 1854), but failed 
 in the House, probably because of the uncertainty as to which of the 
 rival claimants was entitled to the credit of that discovery. 
 
 The resolutions of various scientific and professional societies are 
 appended as an indication of the standing which Dr. Reed occupied in 
 the scientific world at the time of his death. 
 
 The following editorial from a prominent medical journal, American 
 Medicine, is also quoted on account of its pertinence to the question: 
 
 DUE REWARDS FOR SCIENTIFIC ACHIEVEMENTS. 
 
 The recent death of Maj. Walter Reed directs attention to the self-sacrifice of the 
 medical investigator and the inadequacy of the recognition which is attainable in 
 America by these heroes of science. His demise deprives the country of a citizen 
 whose public spirit, devotion to duty, and splendid achievements justly entitle him 
 to an enduring testimonial. His scientific career, strictly speaking, began about 
 1890, when, through the stimulating influence of his illustrious teacher, Dr. Welch, 
 of Johns Hopkins, his interest was awakened in the intimate nature and underlying 
 causes of disease, and he took up the special study of pathology and bacteriology. 
 With rare native intelligence, indefatigable industry, high ideals, broad sympathies, 
 and a personality that attracted all who came in contact with him, he soon distin- 
 guished himself as a trustworthy, independent investigator, and entered upon a work 
 that was to become a triumph for scientific medicine and a blessing to humanity. 
 Notwithstanding his manifold duties as curator of the Army Medical Museum, Reed 
 never lost his love for pure medical investigation, and was a frequent contributor to 
 medical literature. Yet while his contributions in general to scientific medicine are 
 uniformly as good as the best, they are insignificant when compared with the great 
 work upon yellow fever with which his name will ever be inseparably associated. 
 His was the master mind and he the guiding spirit in an investigation whereby mul- 
 titudes of lives have been saved, a pestilential malady robbed of its mysteries and 
 terrors, and an annual expenditure of millions of money shown to be in large part, 
 if not entirely, needless. As has been said, his work "means to the United States for 
 the future a saving in life and treasure that is cheaply paid for by the whole cost of 
 the Spanish- American War." 
 
 In other countries a man who had done such a work as Reed would at once receive 
 office, honors, and financially security. In ours we leave him unrewarded, to work 
 out his life, to die early, perhaps, and then we offer his family a sum as a pension 
 small beyond ridicule. We appeal to Congress to demonstrate the nation's gratitude 
 in this case. It should act promptly and in a manner commensurate with the mag- 
 nificient public service rendered by our colleague. This, we are sure, is the wish of 
 everyone conversant with what he has done. 
 
 RESOLUTIONS OF MEDICAL SOCIETIES AND LEARNED BODIES WITH REF- 
 ERENCE TO MAJ. WALTER REED, SURGEON, UNITED STATES ARMY. 
 
 At a stated meeting of the New York Academy of Medicine, held 
 December 3, 1902, the following resolution was unanimously adopted: 
 
 Whereas in the recent death of Dr. Walter Reed, major and surgeon, United States 
 Army, the science of medicine has lost the one whose brilliant research led first to the 
 
 79965 S. Doc. 822, 61-3 4 
 
50 VER. 
 
 demonstration of the transmission of yellow fever by the mosquito, and later to the 
 practical removal of the disease from a large part of Cuba and the prevention of its 
 transmission to the shores of this country: Be it 
 
 Resolved, That the New York Academy of Medicine records its sens, of the -ivat- 
 ness of the loss to science and to mankind and its sympathy with the friends and 
 relatives of the deceased. 
 
 The following minutes and resolutions were adopted at a special 
 meeting of the faculty of the medical department of the Columbian 
 University: 
 
 The sudden and unexpected demise of our .-t.-.-m.-d friend and colleague. Maj. 
 Walter Reed, United States Army, professor of -y and pathology in the 
 
 medical school of the Columbian University, is an event that brings to us the most 
 acute regret and overwhelming sorrow. 
 
 Taken from us in the prime of manhood and in the /.enith of his professional use- 
 fulness, at a time when the medical profession and humanity at larp< 
 to do him homage for his great work in demonstrating the method of -x terminating 
 yellow fever by pr rom inoculating mosquitoes and by whi< h thai 
 
 disease has been abolished from some of its most malignant haunts at a tin.. 
 when his relations with the faculty and students of the Columbian Ini 
 become securely united by bonds of mutual affection and esteem under th 
 cumstances it is with a most earnest and sincere feeling that we, t h- me -di -al faculty 
 of the Columbian University, hereby desire to express our unreserved admiration for 
 the work, life, and character of Prof. Reed, both as a physician, a te;. 
 friend, and a man of science. In testimony whereof, it is hereby 
 
 Resolved, That the foregoing note be recorded in the permanent archives of the 
 faculty; that a copy of the same be given to the press for publication and also for- 
 warded to the family of Dr. Reed as an evidence of our sympathy for thorn in th-ir 
 great sorrow. 
 
 Resolved, That, as a further mark of respect for our lamented colleague, the exercises 
 of the medical school be suspended ana that the students and faculty attend in a 
 body his funeral obsequies. 
 
 The following resolutions were adopted by the medical faculty of 
 the University of Virginia December 8, 1902, and by them reported to 
 the general faculty, which heartily concurred in this expression ,,f 
 regard for the memory of Dr. Reed, of admiration for his work 
 of sympathy for his family : 
 
 The medical faculty of the University of Virginia have heard with deep sorrow 
 of the death of Maj. Walter Reed, professor of bacteriology and pathology in the 
 Army Medical School, and distinguished graduate of Jrttis medical depart in 
 
 His masterly investigation of the causes of the outbreaks of typhoid f-\cr in the 
 United States Army auring the Spanish-American War, and especially his work 
 furnishing conclusive proof of the conveyance of yellow fever by the mosquito, entitle 
 him to a preeminent place amongst scientists and sanitarians and will prov< 
 mable service to mankind. 
 
 As an alumnus he was true and loyal, manifesting on every appropriate occasion 
 his continued interest in the university, upon which he had reflected great < n dit 
 
 In testimony of our high appreciation of his character and achievements it is hereby 
 
 Resolved, That the foregoing note be spread upon our minutes and a copy L- 
 warded to the family of Dr. Reed as an evidence of our sympathy for them in their 
 great sorrow. 
 
 RESOLUTIONS OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. 
 
 Resolved. That the American Association for the Advancement of ., reby 
 
 records its sense of the great loss sustained by 8eicn> in th<- d< 
 Reed, surgeon in the United States Army, and its appreciation of th f ir r< : 
 and invaluable services which he has rendered to humanity. By solving th problem 
 of the mode of spread of yellow fever, Mai. Reed not only made a great contribution 
 to science, but at the same time conferred inestimable benefits upon his country and 
 upon mankind. To have discovered and demonstrated the methods, which have 
 already been successfully tested in Cuba, of eradicating a widespread and t< rrihlo 
 pestilence, is a benefaction of imperishable renown, of incalculable value in the sav- 
 ing of human lives, of vast importance to commercial interests, and deserving the 
 
YELLOW FEVER. 51 
 
 highest rewards in the power of his countrymen to bestow. This association earn- 
 estly urges upon the attention of Congress the duty of making full provision for the 
 support of his family. 
 
 Resolved, That the president designate a committee of nine members of this associa- 
 tion, with power to increase its number, which shall be authorized and requested to 
 devise and carry out a plan or aid in similar efforts elsewhere instituted, by which 
 a suitable and permanent memorial of this great benefactor of his race may be secured. 
 This committee shall be authorized to prepare and publish a statement of the services 
 of the late Maj. Reed in discovering the mode by which yellow fever may be exter- 
 minated. 
 
 The following resolution was adopted at the meeting of the Ameri- 
 can Medical Association at Saratoga, N. Y., on June 11, 1902: 
 
 Whereas the members of the American Medical Association believe that the recent 
 work of the United States Army surgeons in Cuba in relation to the discovery of the 
 method of transmission of yellow fever is of such magnitude and far-reaching benefi- 
 cence as to rank only second with Tenner's discovery of vaccination; and 
 
 Whereas the practical value of this discovery has been proven by the complete 
 eradication of this scourge from Habana: 
 
 Resolved, That the thanks of this association be tendered the gentlemen who 
 accomplished this brilliant result, and particularly to Drs. Walter Reed, James Car- 
 roll, A. Agramonte, W. O. Gorgas, and to Leonard Wood, who recognized the impor- 
 tance of the work and made it possible by his hearty encouragement and assistance. 
 
 Resolved, That this association, while deeply deploring the death of Dr. Jesse A. 
 Lazear, who died a martyr to science, admires and gratefully acknowledges the heroic 
 devotion of this physician and some of the members of the Hospital Corps to the cause 
 of humanity. 
 
 Resolved, That these resolutions be published in The Journal, and that copies be 
 transmitted to Drs. Reed, Carroll, Agramonte, Wood, Gorgas, and Mrs. Lazear. 
 
 RESOLUTIONS TAKEN BY THE INTERNATIONAL CONGRESS OF MEDICINE AT CAIRO, EGYPT, 
 
 DECEMBER 22, 1902. 
 
 Les membres du Premier Congres de Medecine en Egypte apprennant avec le plus 
 profond regret la mort prematuree du Maj. Walter Reed du Corps Medical de 1'Armee 
 des Etats Unis d'Amerique. 
 
 La part brillante et importante qu'il a pris dans la decouverte du moustique 
 8te"gomyia comme le seul agent transmitteur du parasite de la fievre jaune, reussessant 
 ainsi a mettre les ravages de cette terrible maladie sous le controle des hygienistes 
 fait de sa mort une perte cruelle pour I'humamte. 
 
 Le Congres decide en consequence d'exprimer a cette occasion toute sa sympathie 
 au Corps Medical de 1'Armee des Etats Unis ainsi qu'a la famille du Maj. Reed. 
 
 Le Congres decide en outre de prier le secretaire du Cpngres d'envoyer officielle- 
 ment par 1'entremise des Autorites competentes une copie de la presente resolution 
 au Chirurgien en Chef de PArme'e des Etat Unis d'Amerique et une autre egalment 
 a Madame Veuve Reed. 
 
 [From an editorial in American Medicine (referring to Maj. Reed).] 
 
 His was the master mind and he the guiding spirit in an investigation whereby 
 multitudes of lives have been saved, a pestilential malady robbed of its mysteries 
 and terrors, and an annual expenditure of millions of money shown to be in large 
 part, if not entirely, needless. 
 
 [From the resolutions of the American Association for the Advancement of Science.] 
 
 By solving the problem of the mode of spread of yellow fever Maj. Reed not only 
 made a great contribution to science, but at the same time conferred inestimable 
 benefits upon his country and upon mankind. To have discovered and demonstrated 
 the methods, which have already been successfully tested in Cuba, of eradicating a 
 widespread and terrible pestilence is a benefaction of imperishable renown, of incal- 
 culable value in the saving of human lives, of vast importance to commercial interests, 
 and deserving the highest rewards in the power of his countrymen to bestow. 
 
 [From lecture of Sir Patrick Manson, M. D., medical adviser of the British Colonial Office.] 
 
 Dr. Walter Reed did a great and beneficent work. We in England thoroughly 
 appreciate this, and heartily sympathize with America in the loss she and the world 
 
52 YRLLOW FEVEB. 
 
 has sustained by his premature death. The beet tribute we can pay to hi* mcmor 
 once to apply liia discovery. Let us hope that the good he has done will i. 
 interred with his bones, and that his countrymen and t|u> n-t of us will i 
 push forward the great and beneficent measures hi* brilliant labors so clearly iiui 
 
 Similar resolutions have been passed by numerous other scientific 
 bodies. They arc not given here because it is not desired unduly to 
 lengthen this" report. 
 
 INCORPORATORS OP "THE WALTER REED MEMORIAL ASSOCIATION, " WASHINGTON, D. C. 
 
 R. M. O'Reillv, Surgeon General . tinted States Army. Washington, D. C. 
 
 P. V Surgeon General, United States Navy, Washington, D. C. 
 
 Wa ! I , . D . , Surgeon General, United States Public Health and Ma r i n . 
 
 Hospital Service, Washington, D. C. 
 
 George M. Steinberg, LL. D., brigadier general, United States Army 
 Washington, D 
 
 Calvin Do Witt, brigadier general, United States Army (retired), Washington, D. C. 
 
 Dan i-l 0, oilman, LL. D., president of Carnegie Institution. Washington, D. C. 
 
 ilium. I.L. D., president of Columbian tni\ D. C. 
 
 Carroll D. Wright, LL. D., Commissioner of Labor, Washington, D 
 
 ry B. F. Mac far land, president Board of Commissioners, District of Columbia. 
 
 !1 St. George Turk* r. LI.. D., dean of school of law and diplomacy, Columbian 
 University, Washington, D. C. 
 
 Alexander Graham Bell, LL. D., Columbian University, Washington, D. C. 
 
 G. W r ythe Cook, M. D., LL. D., Washington, D. C. 
 
 A. F. A. King, M. D., dean emeritus medical school, Columbian University, Wash- 
 ington, D. C. 
 
 Chas. Wardell Styles, M. D., Chief of Division of Zoology, Hygienic Laboratory, 
 United States Public Health and Marine-Hospital Service, Washington, D. C. 
 
 W. J. Boardman, Washington, D. C. 
 
 William A. Gordon, lawyer, Washington, D. C. 
 
 Maj. J. R. Kean. surgeon, t'nit<-<l States Army, War Department, Washington, D. C. 
 
 Maj. W. D. McCaw, surgeon, United States Army, War Depar tshington, 
 
 D. O. 
 
 Capt. C. R. Darnall, assistant surgeon, United States Army, W;i rnent, 
 
 Washington, D. C. 
 
 First Lieut. Jas. Carroll, assistant surgeon, United States Army, War Department, 
 Washington, D. C. 
 
 -.Nash, M. D., Washington, D. C. 
 
WALTER REED (SCHULER.. 
 
PART II THE PUBLICATIONS OF WALTER REED AND HIS ASSOCIATES 
 ON THE COMMISSION IN REGARD TO YELLOW FEVER, 
 
 CHAPTER 1. 
 
 BACILLUS ICTEROIDES AND BACILLUS CHOLER33 SUIS A 
 PRELIMINARY NOTE. 
 
 By WALTER REED, M. D., Surgeon, United States Army, and JAMES CARROLL, M. D., 
 Acting Assistant Surgeon, United States Army. 
 
 [Reprinted from the Medical News, April 29, 1899.] 
 
 In the course of a comparative study of Bacillus x (Sternberg) and 
 Bacillus icier oides (Sanarelli) which has engaged our attention as 
 opportunity would permit during the past 18 months, we have had 
 occasion to observe the effect produced by the intravenous injection 
 in dogs of other micro-organisms, such as the Bacillus coli communis 
 and the Bacillus cholerse suis. Without entering into details in this 
 preliminary note we may state that the same clinical symptoms, 
 viz, vomiting, increased action of the bowels, and profound prostra- 
 tion, which are produced in dogs by the intravenous injection of B. 
 icteroides, are also brought about by a like inoculation of the hog- 
 cholera bacillus. When death occurs, the stomach contains a con- 
 siderable quantity of fluid blood and extensive hemorrhagic lesions 
 are present in the small intestine. We have not found fatty degenera- 
 tion of the liver, since our dogs, few in number, injected with the hog- 
 cholera bacillus, have died too early for this change to occur. We 
 have also failed to discover any fatty degeneration in the liver of dogs 
 that have died within a few days after the intravenous injection of 
 B. icteroides. This change has only been met with in two instances, 
 when the animals had survived until the ninth day after inoculation 
 with B. icteroides. In neither of these cases, however, was the degree 
 of fatty degeneration at all comparable with that present in the 
 human liver in yellow fever. 
 
 In addition to the experiments upon dogs, we have compared the 
 course of the infection and the lesions produced in guinea pigs and 
 rabbits inoculated with small quantities of B. icteroides and B. cholerse 
 suis, and have been much impressed with the similarity of the results 
 obtained. The same cyclical course of the infection described by 
 Sanarelli for guinea pigs inoculated with B. icteroides is seen in these 
 animals when injected with like quantities of B. cholerse suis. The 
 greater susceptibility and shorter course of the infection in rabbits 
 applies equally to both micro-organisms. Theobald Smith has called 
 attention to the extreme susceptibility of these animals to inoculation 
 with minute quantities of the hog-cholera bacillus. 1 We have suc- 
 
 i Bulletin No. 6, U. S. Department of Agriculture, 1894. 
 
 53 
 
CHAPTER 2. 
 
 THE ETIOLOGY OF YELLOW FEVER A PRELIMINARY NOTE. 1 
 
 By WALTER REED, M. D., Suryoon, I Hit.-d States Army, JAMES CARROLL, M I> : 
 VORAMOXTB, M. D., and JESSE W. LAZEAR, M. D., 1 Acting Assistant Surgeon, 
 United States Army. 
 
 The writer-. c<>nM inning a board of medical officers convened ''for 
 the purpose or pursuing scientific investigations with n-fViviu <> t> the 
 acute infectious diseases prevalent on the Island of Cul>;i." arrived 
 at our station, Columbia Barracks, Quemados, Cuba, on June 25 of 
 the present year, and proceeded, under written instructions from the 
 Surgeon General of the Army. t> "gjve special attention to questions 
 relatini: to the etiology and prevention of yellow fe\ 
 
 TWO Of its members (Airnimnnte :md L&zear) were stationed on the 
 Island of Cuba, the former in Habana, and the latter at Columbia 
 Barracks, and were already pursuing investigations relating to the 4 
 etiology of this disease. 
 
 Fortunately for the purposes of this board, an epidemic <>f yellow 
 fever was prevailing in the adjacent town of Quemados, Cuba, at the 
 time of our arrival, thus furnishing us an opportunity I'm- <li 
 observations and for bacteriological and pathological work. The 
 results already obtained, we believe, warrant the publication at this 
 t ime of a preliminary note. A more detailed account of our obs< 
 tions will be submitted to Surgeon General Sternberg in a future 
 report. 
 
 The first part of this preliminary note will deal with the result 
 blood cultures during life and of cultures taken from yellow I 
 cadavers, reserving for the second part a consideration of the 
 mosquito as instrumental in the propagation of yellow fever, with 
 observations based on the biting of nonimmune human beings by 
 mosquitoes which had fed on patients sick with yellow fever, at 
 various intervals prior to the biting. 
 
 In prosecuting the first part of our work, we isolated a variety of 
 bacteria, but of these we do not propose to speak at present. It will 
 suffice for our purpose if we state the results as regards the findii 
 bacillus icteroides, leaving the mention of other bacteria to our detailed 
 report. 
 
 The cases studied during the Quemados epidemic had been diag- 
 nosed by a board of physicians selected largely by reason of their 
 familiarity with yellow fever. This board consisted of Drs. Nicola 
 Silverio, Manuel Herera, Eduardo Angles, and Acting Asst. Si 
 Roger P. Ames and Jesse W. Lazear, United States Army. 
 
 Those studied in Ilabana were patients in Las Animas Hospital 
 and had been diagnosed as such by a board of distinguished practi- 
 tioners of that city. 
 
 An examination of Table I will show the character of the attacks. 
 
 The milder cases studied, few in number -, were attended by jaundice 
 and albumen in the urine. 
 
 > Reprinted from the Proceeding* of the Twenty-eighth Annual Meeting of the American Public Health 
 Aaocfatlon, Indianapolis, Ind., CM. 22, 23. 24, 25, and 2ft, 1900. 
 Died of yellow fever at Columbia Barracks, Cuba, Sept. 25, 1900. 
 
YELLOW FEVEK. 
 
 57 
 
 I. BACILLUS ICTEROIDES (SANARELLI) AS THE CAUSE OF YELLOW 
 
 FEVER. 
 
 The claim of Sanarelli for the specific character of B. icteroides as 
 the causative agent in yellow fever has excited such wide attention 
 since the publication of his observations that it seemed to us of the 
 first importance to give our undivided attention to the isolation of 
 this microorganism from the blood of those sick with yellow fever 
 and from the blood and organs of yellow-fever cadavers. 
 
 (A) CULTURES TAKEN FROM THE BLOOD DURING LIFE. 
 
 The method followed was that ordinarily used in an attempt to 
 isolate bacteria from the circulating blood, viz, from a vein at the 
 bend of the elbow a sufficient quantity of blood was taken with a 
 hypodermic syringe, made sterile by boiling, and after careful cleans- 
 ing of the skin with soap and water, followed by equal parts of abso- 
 lute alcohol and ether, and 1-2000 bichloride solution. 
 
 Exceptionally, the blood withdrawn was plated on agar, but as a 
 rule it was immediately transferred to sterile bouillon tubes (10 c. c.) 
 in quantities of 0.5 c. c. to each of several tubes. These were then 
 incubated at 35 to 37 C. for a period of one week. They were 
 examined daily, and if growth was observed plates in agar or gelatine, 
 or both, were made and the colonies carefully studied by transference 
 to ordinary laboratory media. 
 
 Eighteen cases have thus been carefully studied; of these 11 
 were designated as " severe" cases of yellow fever, with 4 deaths; 3 as 
 " well-marked" cases, with no deaths; and 4 as "mild" cases, with 
 no deaths. 
 
 From these 18 cases blood cultures were made, as shown in the 
 following table: 
 
 TABLE I. Blood cultures during life. 
 
 Day of disease. 
 
 Character of attack. 
 
 Number 
 of cul- 
 tures. 
 
 Number 
 of bouil- 
 lon tubes 
 inocu- 
 lated. 
 
 B. icteroides. 
 
 First 
 
 Severe 
 
 3- 
 
 14, 
 
 Negative. 
 
 Do 
 
 Well marked 
 
 1 
 
 4 
 
 Do. 
 
 Do 
 
 Mild 
 
 1 
 
 3 
 
 Do. 
 
 Second 
 
 Severe 
 
 6 
 
 18 
 
 Do. 
 
 Do 
 
 Well marked 
 
 1 
 
 2 
 
 Do. 
 
 Do 
 
 Mild 
 
 1 
 
 3 
 
 Do. 
 
 Third 
 
 Severe 
 
 7 
 
 a 18 
 
 Do. 
 
 Do 
 
 Mild 
 
 2 
 
 4 
 
 Do. 
 
 Fourth 
 
 
 5 
 
 14 
 
 Do. 
 
 Do 
 
 Well marked ' 
 
 2 
 
 6 
 
 Do. 
 
 Do 
 
 Mild 
 
 1 
 
 1 
 
 Do. 
 
 Fifth 
 
 Severe 
 
 5 
 
 U2 
 
 Do. 
 
 Do 
 
 Well marked 
 
 1 
 
 3 
 
 Do. 
 
 Do 
 
 Mild 
 
 1 
 
 1 
 
 Do. 
 
 Sixth 
 
 
 4 
 
 6 
 
 Do. 
 
 Do 
 
 Well marked 
 
 I 
 
 2 
 
 Do. 
 
 Seventh 
 
 
 1 
 
 2 
 
 Do. 
 
 Do 
 
 Well marked 
 
 1 
 
 2 
 
 Do. 
 
 Eighth 
 
 Severe 
 
 2 
 
 6 
 
 Do. 
 
 Do 
 
 Well marked 
 
 1 
 
 2 
 
 Do. 
 
 Ninth 
 
 Severe 
 
 1 
 
 2 
 
 .Do. 
 
 
 
 
 f- 
 
 
 1 3 agar plates. 
 
 2 6 agar pla! 
 
 Number of cultures 
 
 Number of bouillon tubes inoculated. 
 Number of agar plates 
 
 48 
 115 
 15 
 
r.s 
 
 YKLLOXV FKVKR. 
 
 It will be seen that of 48 separate cultures made from the blood on 
 various days of the disease and representing 115 bouillon inoculat i. >ns 
 and 18 agar plates, we failed to find BadMua icteroides in any of our 
 tubes or plates. 
 
 The results of cultures taken hi 18 l cases of unmistakable yell<>\\ 
 fever. mi \ arious days of the disease and in some cases on ev TV day 
 from the onset to death or recovery, would seem to exclude the 
 presence of Bacillus icteraides in the ll<.d of these cases durini: life. 
 
 1 1 will therefore be seen that while Wasdin and Gedd ings inking 
 cultures from the ear lobe (Report on the Cause of Yellow Krver. 
 1899), record that "in the blood of yellow-fever cases extract eel 
 during life BaciUus icteroides has been found in 13 of the 14 cases, 
 with 1 negative" (92.85 per cent), we, by withdrawing blond from 
 the veins of 18 patients, have to record 100 per cent of failures. 
 
 We have already stated that \\e will reserve for a lat.-r report a 
 description of the hacteria isolated from tlie blond in these cases. We 
 now remark that but tew organisms wore obtained and that, as a 
 rule, our hlood cultures guvi' no growth whatever. 
 
 (B) CULTURES FROM YELLOW-FEVER CADAVERS. 
 
 We tried to obtain autopsies very soon after death and sometimes 
 ed in doing so. Tubes containing about 10 c. c. of llesh-peptone 
 bouillon were generally used for the first inoculation, direct from the 
 blood and organs. As soon as the laboratory was reached, aga r plates 
 were made from these inoculated bouillon tubes, the former as well 
 as the latter being then incubated at 35-37 C. In nearh every 
 case gelatin plates were also made from the recently inocul 
 bouillon tubes and kept at a temperature of 19-20 C. 
 
 If colonies were found in the agar or gelatin plates on the following 
 days, the corresponding bouillon tubes were also plated on agar 
 gelatin. The bacteria thus found in our plates were carefully iso- 
 lated and studied upon the usual nutritive media, so as to enaole us 
 to identify them it possible. We will here content ourselves \\ith 
 giving the results as regards the presence of B. icteroides only. 
 
 TABLE II. 
 
 No. of 
 
 BMI 
 
 Day of disease. 
 
 Time of autopsy. 
 
 Source of culture. 
 
 B. icteroides. 
 
 1 
 
 Seventh . 
 
 2 hours after death . . 
 
 Blood, liver, spleen, kidney. . . 
 
 Negative. 
 
 2 
 
 Sixth 
 
 13 hours after death 
 
 do 
 
 Do 
 
 3 
 
 Fourth 
 
 8 hours after death 
 
 do 
 
 Do 
 
 
 . 
 Fourth 
 
 4 hours after death.... 
 . . .do 
 
 Abdominal cavity, blood, liver, spleen, 
 kidney, bile, duodenum. 
 Blood, liver, spleen, kidney, bile, duode- 
 
 Do. 
 Do. 
 
 
 Sixth 
 
 6} hours after death . . . 
 
 num. 
 Abdominal cavity, blood, pericardia! 
 
 Do. 
 
 
 do. 
 do. 
 
 50 minutes after death. 
 ^ hour after death 
 
 lluid. IUIIK. Spleen, kidney, lj\. 
 duodenum 
 Blood, lung, liver, spleen, kidn- 
 jejunum. 
 Blood, lung, liver, spleen, kidney, urine, 
 
 Do. 
 
 
 Fourth 
 
 2 hours after death 
 
 Mllllll i'ltr li'ir 
 
 Liver, spleen, small intestine 
 
 Do. 
 
 10 
 
 mfe 
 
 7 h<, i: iffest !< ith 
 
 . idney, spleen, small intestine. . , 
 
 Do. 
 
 11 
 
 Third 
 
 } hour after death 
 
 . idneyi spleen' 
 
 Do. 
 
 
 
 
 
 
 ' Cultures from the blood during life had been taken by Dr. Lazeur in three other cases of yellow fever, 
 
 .' - -.-.;. .,.'.,.: ,....,;,, .;.;/..:.,",: . , ,., ... . . , ,,:. v. M, ' , ultunvs 
 
 had been taken can not be ascertained. These cultures were negative as regards the finding of SanarelU's 
 
YELLOW FEVER. 59 
 
 Our failure to isolate B. icteroides in these 11 autopsies of yellow- 
 fever patients was a result which we had not anticipated. One of us 
 (Agramonte) who at Santiago, Cuba, during the epidemic of 1898, 
 succeeded in finding B. icteroides in 33 per cent of his autopsies, has 
 been much surprised at the absence of this bacillus in cultures from 
 cadavers sectioned in Habana during the present year. In 2 of the 
 11 cases we had reason to believe that from the character of colonies 
 seen in gelatin plates we would be able to isolate B. icteroides. These 
 colonies, however, when transferred to other media and carefully 
 studied, did not prove to be this bacillus. We wonder whether other 
 observers have occasionally relied upon the appearance of colonies in 
 gelatin plates without further study. We only mention this as a pos- 
 sible explanation of the large percentage of positive results recorded 
 by some observers. 
 
 Pothier, of New Orleans, La., only succeeded, however, in isolating 
 B. icteroides in 3 out of 51 autopsies. (Journal of American Medical 
 Association, Apr. 16, 1898.) 
 
 Lutz (Revista D'Igiene e Sanita Publica, XI, No. 13, July, 1900, 
 pp. 474-475), says, as the result of his extensive observations on yellow 
 fever, that Bacillus icteroides can not be found by present laboratory 
 methods in more than half of the cases of yellow fever, and that when 
 present the colonies are few in number. 
 
 It is possible that our future autopsies may give more favorable 
 results as regards B. icteroides. 
 
 II. THE MOSQUITO AS THE HOST OF THE PARASITE OF YELLOW FEVER. 
 
 Having failed to isolate B. icteroides either from the blood during 
 life or from the blood and organs of cadavers, two courses of procedure 
 in our further investigations appeared to be deserving of attention, viz, 
 first, a careful study of the intestinal flora in yellow fever in compari- 
 son with the bacteria that we might isolate from the intestinal canal of 
 healthy individuals in this vicinity or of those sick with other dis- 
 eases; or, secondly, to give our attention to the theory of the propaga- 
 tion of yellow fever by means of the mosquito a theory first advanced 
 and ingeniously discussed by Dr. Carlos J. Finlay, of Habana, in 1881. 
 (Anales de la Real Academia, voTTS, ISSlTpf liT^lBQ.) ^ 
 
 We were influenced to take up the second line of investigation by 
 reason of the well-known facts connected with the epidemiology of 
 this disease, and of course by the brilliant work of Ross and the Italian 
 observers in connection with the theory of the propagation of malaria 
 by the mosquito. 
 
 We were also much impressed by the valuable observations made 
 at Orwood and Taylor, Miss., during the year 1898, by Surg. Henry 
 R. Carter, United States Marine-Hospital Service. A note on the 
 interval between infecting and secondary cases of yellow fever, etc. 
 (Reprint from New Orleans Medical Journal, May, 1900.) We do not 
 believe that sufficient importance has been accorded these painstaking 
 and valuable data. We observe that the members of the yellow-fever 
 commission of the Liverpool School of Tropical Medicine, DBS. Dur- 
 ham and Myers, to whom we had the pleasure of submitting Carter's 
 observations, have been equally impressed by their importance. 
 (British Medical Journal, Sept. 8, 1900, pp. 656-657.) 
 
60 
 
 The circumstances under which Carter worked were favorable for 
 recording with considerable accurac\ the interval between the time of 
 arrival of infecting cases in isolated farmhouses and the occurrence of 
 secondary cases in these houses. Accord in ter, 'the period 
 
 from the first < infect ing) case to the first group of cases infected at 
 these houses is generally from two to three \ 
 
 The houses having now become infected, susceptible individuals 
 there siting the houses for a few hours fall side with the disease 
 
 in the usual period of incubation one n days. 
 
 her observations made by u> >ince our arrival conlirmed ( arter's 
 hisions. thus pointing, as it seemed to us, to the pr. ! an 
 
 intermediate host, such as the mosquito, which, having taken tin- 
 parasite into its stomach soon after the entrance of the patient into 
 the noninfected house, was able after a certain interval to reconvey 
 the infecting agent to other individuals, thereby converting a nmi- 
 infectcd house into an "infected '' house. This interval would apnear 
 to be from 9 to 16 days (allowing for the period of incubation '. which 
 agrees fairly closely with the time required for the passage of the 
 malarial parasite from the stomach of the mosquito to its salivary 
 glands. 
 
 In view of the foregoing observations we concluded to test the 
 theory of Finlay on human beings. According to this author's oi 
 vation of numerous inoculations in 90 individuals, the application of 
 one or two contaminated mosquitoes is not dangerous, out followed 
 in about 18 per cent by an attack of what he considers to be very 
 benign yellow fever at the most. 
 
 We Here desire to express our sincere thanks to Dr. Finlay, who 
 accorded us a most courteous interview, and has gladly placecl at our 
 disposal his several publications relating to yellow fever during tin- 
 past 19 years; and also for ova of the species of mosquito with 
 which he had made his several inoculations. An important 
 tion to be here recorded is that, according to Finlay s statement. :;n 
 days prior to our visit, these ova had been deposited by a female just 
 at'theedgeof the water in a small basin, whose contents had 
 allowed to slightly evaporate, so that these ova were at the time of our 
 visit entirely above contact with the water. Notwithstanding this 
 long interval after deposition, they were prompt Iv converted into the 
 larval stage, after a snort period, by raising the level of the water in 
 the basin. 
 
 With the mosquitoes thus obtained we have been able to conduct 
 our experiments. Specimens of this mosquito forwarded to Mr. L. 
 O. Howard, entomologist, Department of Agriculture, Washington, 
 D. C., were kindly identified as CulexfasciatusF&br. 
 
 In this preliminary note we have not space to refer at length to 
 the various interesting and valuable contributions made by Kinlay to 
 the mosquito theory for the propagation of yellow fever. In addition 
 to the paper already quotea, his most valuable contributions to this 
 important theorv are to be found in the articles designated as follows: 
 Estadistica de las Inoculaciones con mosquitos contaminados, ct< ., 
 reprint, Havana, 1891 : Fiebre Amarilla. Estudio Clinico Patnl.,gimy 
 Ktiologico, reprint. Habana, 1895; and Yellow lY\er Immunity- 
 Modes of Propagation: Mosquito Theory, 8th Congress of Interna- 
 tional Hygienic and Demography, Budapest, 1894. 
 
YELLOW FEVER. 61 
 
 His present views on this subject may be stated in his own language : 
 " First, reproduction of the disease, in a mild form, within 5 to 
 25 days after having applied contaminated mosquitoes to susceptible 
 subjects. Second, partial or complete immunity against yellow fever 
 obtained when even no pathogenous manifestation had followed 
 those inoculations." (Medical Eecord, vol 55, No. 21, May 27, 1899.) 
 
 Without reviewing the cases regarded as mild forms by the author 
 of this theory, we believe that he has not as yet succeeded in repro- 
 ducing a well-marked attack of yellow fever within the usual period 
 of incubation of the disease, attended by albumen and jaundice, and 
 in which all other sources of infection could be excluded. 
 
 The experiments made by us on eleven nonimmune individuals are 
 embraced in the following table, which should be carefully studied. 
 
 The mosquito used in all cases was Culexfasciatus Fabr. 
 
62 
 
 YELLOW FEVER, 
 o - 
 
 t 
 
 li* 
 
 ^- Ct 
 
 f.'. lion of 
 qulto and 
 culation. 
 
 SOOtf 0COW 
 
 111 1! 
 
 "OR : "o 
 
 S : : : 
 
 
 :c' 
 
 lilll 
 
 -v:fafa< 
 
 I 
 
YELLOW FEVER. 63 
 
 It will be seen that we record 9 negative and 2 positive results. 
 It is, we think, important to observe that of the 9 failures to infect, 
 the tune elapsing between the biting of the mosquito and the inocu- 
 lation of the healthy subject varied in 7 cases from 2 to 8 days (Nos. 1, 
 2, 3, 4, 5, 7, and 9), and in the remaining two from 10 to 13 days (Nos. 
 6 and 8). 
 
 Five individuals out of the 9 who failed to show any result (Nos. 
 2, 3, 4, 5, and 6) were inoculated by mosquitoes that had bitten very 
 mild cases of yellow fever on the fifth day of the disease, and one 
 individual by a mosquito that had bitten a mild case of yellow fever 
 on the seventh day of the disease. (This latter patient was discharged 
 from hospital 3 days later.) To this fact may possibly be attributed 
 the negative results. Of the remaining 3 negative cases (Nos. 7, 8, 
 and 9), and which had been inoculated by mosquitoes that had bitten 
 severe cases of the disease, the interval between the bite and the 
 inoculation varied from 2 to 6 days. 
 
 In the 2 cases (Nos. 6 and 8) where the interval was respectively 
 10 and 13 days, the inoculations had been made with mosquitoes that 
 had bitten very mild cases of yellow fever on the fifth day of the 
 attack. No. 8 was also bitten by a mosquito which had been infected 
 by a severe case of yellow fever 3 days before. 
 
 We refrain from commenting further at this time upon the 9 
 negative cases, preferring to record the results obtained rather than 
 to indulge in speculation. 
 
 Of the two cases which we have recorded as positive in Table III, 
 we now propose to speak at greater length. i 
 
 Case 10, Dr. James Carroll, acting assistant surgeon, United States Army, a member 1 
 of this board, was bitten at 2 p. m., August 27, 1900, by Culexfasciatus. This particu- ) 
 lar mosquito had bitten a severe case of yellow fever on the second day of the disease 12 \ 
 days before; a mild case of yellow fever, on the first day of the attack, 6 days preceding;,/ 
 a severe case of yellow fever, on the second day of the attack, 4 days before; a mild I 
 case of yellow fever, on the second day of attack, 2 days before inoculation. 
 
 Dr. Carroll remained well until the afternoon of the 29th, when he states that he 
 felt tired, and for this reason, when on a visit to Las Animas Hospital, the same after- 
 noon (29th), some time between 4 and 6 p. m., after visiting a few patients, he left 
 the wards and waited outside on the porch, while his companions remained in the 
 wards. 
 
 August 30: During the afternoon, although not feeling well, Dr. Carroll visited La 
 Playa, distant about 1J miles from Columbia Barracks, and took a sea bath. 
 
 August 31 , a. m.: Dr. Carroll realized that he was sick and that he had fever, although 
 he refrained from taking his temperature, but did visit the laboratory, distant about 
 140 yards, for the purpose of examining his blood for the malarial parasite. The 
 examination was negative. During the afternoon he was compelled to take to his 
 bed. At 7 p. m. temperature was 102 F. No headache nor backache; only a sense 
 of great lassitude. Eyes injected and face suffused. 
 
 September 1, 7 a. m.: Temperature 102 F. Blood again carefully examined by Dr. 
 Lazear with negative results. 
 
 11 a.m.: Temperature 102. 
 
 The case having been diagnosed as one of yellow fever, Dr. Carroll was at noon , 
 removed to the yellow fever wards. 
 
 9 p. m.: Temperature 102.8, pulse 90; 12 o'clock midnight, temperature 103.4, 
 pulse 84. 
 
 September 2, 3 a. m.: Temperature 103.6, pulse 80. A trace of albumen was now 
 found in the urine. The subsequent history of the case was one of severe yellow 
 fever. Jaundice appeared on September 3. 
 
 The accompanying chart No. 1 contains all of the necessary data. 
 
 The question of diagnosis having been clearly and easily estab- 
 lished, it now becomes important to follow Dr. Carroll's movements 
 for a period of 10 days preceding the mosquito inoculation, and 
 
64 
 
 YKLLONV FKYEK. 
 
YELLOW FEVER. 65 
 
 during the period elapsing from the bite of the insect until the com- 
 mencement of the attack. 
 
 On August 21, 22, and 23, Dr. Carroll was at Columbia Barracks, 
 outside of the epidemic zone. On August 24 he visited the autopsy 
 room of Military Hospital No. 1, which is situated on Principe Hill 
 overlooking the city of Habana. He was present in this autopsy 
 room while an autopsy was made by Dr. Agramonte on a case of per- 
 nicious malarial fever. Dr. Carroll only took cultures from the 
 blood and organs as the section proceeded. He was there about half 
 an hour and then returned to Columbia Barracks. Subsequent 
 microscopic study of sections of the liver and spleen showed that the 
 case autopsied on the 29th was really a case of pernicious malarial 
 fever. 
 
 It should be stated that although cases of yellow fever are not 
 admitted to Military Hospital No. 1, an English sea captain had been 
 admitted to its wards a few days before, whose case developed into 
 one of yellow fever with fatal result, and the body had been autopsied 
 by Dr. Agramonte in this dead room on the day preceding Dr. Car- 
 roll's visit to it. ^ 
 
 According to Dr. Carroll, the room was by no means in a cleanly 
 condition. As Dr. Carroll's visit to this room was made on August 24, * 
 and as he began to complain on August 29, about the average period 
 of incubation of yellow fever, there is a possible chance for infection 
 in this way. We must call attention, however, to the fact that Dr. '' 
 Agramonte, whenever he performs an autopsy in this room, is always 
 attended by a young soldier of the Hospital Corps, United States 
 Army, who is detailed for that purpose, and whose duty it is to assist - 
 and to afterwards attend to the cleaning of the autopsy table. This 
 soldier, a nonimmune American, was present when Dr. Carroll was: 
 there and remained afterwards to attend to his duties. He has notj 
 contracted yellow-fever by his duties in this room from time to time/ 
 Our own experience would seem to accord with that of others, viz, 
 that attendance upon autopsies and the handling of portions of | 
 organs of yellow-fever cases removed to the laboratory is unattended" 
 with danger. Certainly the three nonimmune members of this board, ; 
 up to the time of these mosquito inoculations, had during the pastj 
 three months come in close contact with the dead bodies and organs 
 of yellow-fever cases, freely handling and examining these organs, 
 including the small intestine, even kept at thermostat temperature 
 for 24 hours, without contracting the disease. We have, of course, 
 never neglected to cleanse our hands with disinfectants. 
 
 Dr. Carroll upon his visit to the before-mentioned dead room only 
 used the platinum loop for taking cultures and did not come in contact 
 with the autopsy table. 
 
 The only other opportunity for infection in his case would appear 
 to have been during his visit to Las Animas Hospital, situated in the 
 suburbs of Habana, as here yellow-fever patients are admitted in 
 large numbers. We have already pointed out that Dr. Carroll was 
 complaining of lassitude at the hour of his visit, which was about 50 
 hours after his inoculation with the contaminated mosquito. We 
 have also called attention to the fact that he remained for the greater 
 part of his visit outside of the hospital, on the piazza. This would 
 
 79965 S. Doc. 822, 61-3 5 
 
66 YKU.oU i l.VER. 
 
 appear to caM doubt upon hi> \ Uit to Las Aninias as the sour- 
 his infection. 
 
 Wo do not wish to be understood as unnecessarily seeking to lay 
 too much emphasis upon the exclusion in this ease of other sources 
 of infection than the mosquito, as we fully appreciate that Dr. Carroll 
 had been on two occasions within the epidemic zone during the week 
 
 ding his attack of yellow fever. His movements on these ,. 
 sions we have already given. 
 
 We will again refer to Dr. Carroll's case after we have given the 
 history of case No. 11, which we have designated as our second posi- 
 tive result. ^ *v+& /* &<-**- 'fci+vjt fB Jjtt C^^r 
 
 COM 11. X. Y., white, American, a resident of me military reservation of < \.hnn- 
 bia Barracks, was bin (Mi during the forenoon of the 31st day of A ">n, 1>\- ihe 
 
 same mosquito that had bitten case 10 (I M an.. 11) 4 days before, and which in tin- 
 meanwhile had bitten a mild case of yellow fever (first day) 2 dayn before being applied 
 toX Y. 
 
 \. V . was also bitten by a second mosquito that had been applied to a 
 of yellow fever (second day) U days before, and to 2 mild cases (HM-..M| day) 1 and 10 
 days previously; also, by a third mosquito that had bitten a fatal case "i" yrll<>\\ 
 (second day) 12 days before, a severe case (first day) 2 days bef> 
 (first, second, and third day) 4, 6, and 10 days before; finally, by a fourth mosquito 
 that had bitten 3 severe cases of yellow fever (all on the first day) L' days 
 
 previously, and 1 mild case (second dav) 6 days before. (Vide Ta i !< 111.) 
 
 It will thus be seen that X. Y. was oitten by 4 mosquitoes, 2 of whi^h had i 
 severe (fatal) cases of yellow fever 12 days previously, one of which had hit t 
 case (second day) 16 days before, and one which had bitten a severe case (lir-t day; 
 
 8 days before. 
 
 September 25. X. Y. began to experience a sense of dizziness and di.-im linai 
 work. This was just 5 days from the time of the mosquito inoculation. 
 
 Twenty-four hours later, still dizzy and light-headed in attempting to move about. 
 During the afternoon (sixth day after inoculation) chilly sensations, followed \>\ 
 and restlessness during the night. 
 
 On the following day (seventh day after inoculation), 8 a. m., temperature 1 ():_'. ^ I . 
 eyes slightly injected, lace suffused. Patient removed to the yellow fever . 
 
 9 a. m., temperature 103 F., pulse GG. A trace of albumen was found in the urine 
 during the afternoon (third day of the attack). This increased during the following 
 days. Conjunctive slightly jaundiced on the fourth day of disease, which was more 
 distinct and could be plainly seen on anterior aspect of chest on the fifth and following 
 day. Bleeding from the gums was noticed on the third and subsequent 
 admission. Repeated examinations of the blood failed to show any malarial parasites. 
 
 The course of the fever, the appearance of albumen in the urine, 
 with jaundice and hemorrhage from the gums, together with the slow 
 pulse, all pointed distinctly to the diagnosis of yellow fever. His 
 attending physician, Dr. lloger P. Ames, United States Army, an 
 expert in the diagnosis and treatment of this disease, did n<>i lie-it ate 
 to diagnose X. Y.'s attack as one of "well-pronounced yello\v fe\ 
 Dr. Ames was not cognizant of the method of inoctilat ion in this case. 
 (Vide, Chart EL) 
 
 The diagnosis, therefore, not being in doubt, we must follow this 
 patient's movements during the 10 days preceding the bite of the 
 mosquitoes and from this time until 5 days later, when the attack 
 began. It so happens that we can follow X. Y.'s movements I'm- a 
 much longer period. Fifty-seven days prior to his inoculation, he 
 spent a day and night in the city of Habana. Sixteen days before the 
 inoculation, he rode on horseback with 6 other nonimmunes a dis- 
 tance of about IJ mile^ toward the seashore and returned to his 
 dwelling, without in the meantime dismounting from his limse. 
 
 From this time until hi^ complete convalescence was established, lie 
 
YELLOW FEVER. 
 
 67 
 
 had remained within the immediate vicinity of his home. So that it 
 may be positively stated that X. Y. had not absented himself from the 
 military reservation of Columbia Barracks during a period of 57 
 days prior to his inoculation (with the exception above stated), 
 nor between the date of his inoculation and the establishment of con- 
 valescence. 
 
 Let us now inquire whether the military reservation of Columbia 
 Barracks is outside of the epidemic zone of yellow fever. To this 
 
 N 
 
 44 
 
 ^?o 
 
 ^S 
 
 $ s 
 
 !t^ 
 
 K*5:5 
 
 fc^ 
 kll 
 
 V 
 
 &t 
 
 s 
 
 1> ^ v* 
 
 ?W 
 
 
 \ 
 
 we answer that since the commencement of the present epidemic of 
 yellow fever in Habana, dating from May, 1900, the average monthly 
 population of this station, including civilian employees, has been 
 1,400, nearly all of whom are young nonimmunes. * 
 
 There have occurred amongst this nonimmune population from 
 May 1 to October 13, 1900, 16 cases of yellow fever, all of which 
 have been easily and readily traced to a visit to within the boundaries 
 of the epidemic zone, except cases 10 and 11 of Table III, and 1 
 
68 
 
 other case of which wo shall presently speak. T 
 ributed as follows: 
 
 rases. 
 
 May 24... 
 June 10... 
 Jum 
 
 June 19... 
 June 21... 
 June 29... 
 July 9.. 
 July 26. 
 July 29. 
 
 u 
 
 Aui.16. 
 
 Au.vSl 
 
 Sept. 19 . 
 
 Total 
 
 Ten of these cases have occurred amount an average mnn: 
 military population of 1,295 men, and 6 cases in an average Civilian 
 population of 105. 
 
 Whenever these cases have occurred, as soon as the patient 
 been removed to hospital most careful mea*i 
 been immediately carried out by a trained sanitary squad, tmd: 
 personal supervision of a medical ollicer. I of 
 
 destruction by fire of mattresses, the disinfection 
 clothing with 1 to 500 bichloride solution, and the application o 
 same solution freely to the ceiling, walls, and floor- 
 force pump. 
 
 We repeat that no case has ever been connected with a preceding 
 case, but that the source of infection has he-. 
 occurred during the individual's visit to Habana, r> mil.- 
 to some other nearer Cuban settlement. 
 
 We now invite attention to the fact that from August 17 to ( )< -tnh< -r 
 13, a period of 57 days, only 3 cases of yellow fevrr have occu 
 amongst this population of 1,400 nonimnmm and \\ e 
 
 consider it very important to note that two of these had 
 within 5 days of the commencement of their attack, by < n/itamii 
 mosquitoes. 
 
 Taken in connection with case 'J. in which 
 find any other source of infection than the bite of 
 quito, 5 days preceding the at t ark. the 
 lO-Table III) Decomes strongly confirmatory of the sa n. 
 
 We will now briefly give the history of the t hird case of yell- 
 that has occurred at Columbia Barracks during the period A 
 to October 13, 1900. 
 
 In the light of cases 10 and 11 we consider this case of suflicicnt 
 importance to be here Included, especially as it is one that might he 
 possibly designated as a case of accidental ini'eetion by a mo 
 
 Cote. Dr. Jesse \V . Lazear. acting assistant surgeon. United States .A i 
 of this board, was bin, n Hi, 1900 (case 
 
 fatciatus) which 10 davs previously had be<Mi <-MIII;IH mild 
 
 case of yellow fever (fifth day). No appreciable di.-tiirbanro of health i< -II \\< <! ihiw 
 inociikii; 
 
 1900 (forenoon): Dr. l^azear, v hil- 
 and while collecting blood from yellow-fever pat i< 
 
V 111, LOW FEVKK. 69 
 
 mosquito (species undertermined). As Dr. Lazear had been previously bitten by a 
 contaminated insect without after effects, he deliberately allowed this particular 
 mosquito, which had settled on the back of his hand, to remain until it had satisfied 
 its hunger. 
 
 On the evening of September 18, 5 days after the bite, Dr. Lazear complained of 
 feeling "out of sorts," and had a chill at 8 p. m. 
 
 September 19: Twelve o'clock noon, temperature 102.4, pulse, 112. Eyes injected, 
 face suffused; 3 p. m., temperature, 103.4, pulse, 104; 6 p. m., temperature, 103.8, 
 pulse, 106. Albumen appeared in the urine. Jaundice appeared on the third day. 
 The subsequent history of this case was one of progressive and fatal yellow fever, the 
 death of our much lamented colleague having occurred on the evening of Septem- 
 ber 25, 1900. 
 
 As Dr. Lazear was bitten by a mosquito while present in the wards 
 of a yellow-fever hospital, one must, at least, admit the possibility of 
 this insect's contamination by a previous bite of a yellow-fever 
 patient. This case of accidental infection therefore can not fail to 
 be of interest, taken in connection with cases 10 and 11. 
 
 For ourselves, we have been profoundly impressed with the mode of 
 infection and with the results that followed the bite of the mosquito 
 in these three cases. Our results would appear to throw new light 
 on Carter's observations in Mississippi, as to the period required 
 between the introduction of the first (infecting) case and the occur- 
 rence of secondary cases of yellow fever. 
 
 Since we here, for the first time, record a case in which a typical 
 attack of yellow fever has followed the bite of an infected mosquito, 
 within the usual period of incubation of the disease, and in which 
 other sources of infection can be excluded, we feel confident that the 
 publication of these observations must excite renewed interest in the 
 mosquito theory of the' propagation of yellow fever, as first proposed 
 by Finlay. 
 
 From our study thus far of yellow fever, we draw the following 
 conclusions : 
 
 1. Bacillus icteroides (Sanarelli) stands in no causative relation to 
 yellow fever, but when present should be considered as a secondary 
 invader in this disease. 
 
 , The mosquito serves as the intermediate host for the parasite of 1) 
 yellow fever. 
 
 
CHAT i- 1 
 THE ETIOLOGY OF YELLOW FEVER. AN ADDITIONAL NOTE. 1 
 
 \YAI.TBRREED.' <! Statee Ann 
 
 TIDES AQRAMOMI M I> . Art ing Assistant Surgeons, United States A i 
 
 At the twent\ -eighth annual meeting of the American Public I lealth 
 
 Association, 3 held in Indianapolis. End., Octoher I' _'-_';. P.MMI, \\e piv- 
 
 M-nted. in the form of a preliminary note, the results of our bac 
 teriologic study of yellow fever, based on cultures taken from tin' Mood 
 in 18 cases at various stages of the disease, as well as on th.se which 
 we have made from the blood and organs of 11 yelh>w-fever < 
 We also recorded the results obtained from the inoculation of 11 non- 
 immune individuals by means of the bite of mosquit* 
 
 Kabr.) that had previously fed on the blood of patients sick with 
 yellow fever. We were able to report two positive results. in which 
 the attack of yellow fever followea the bite of a mosquito \\ ithin the 
 usual period of incubation of this disease. 
 
 In one of these cases all other sources of infection could !>c j 
 tivclv excluded. From our several observations we drew the follow- 
 ing conclusions: (1) BadUus icteroides (Sanarelli) stands in DO causa- 
 tive relation to yellow fever, but when present should be considered 
 as a secondary invader in this disease. (2) The mosquito sen e 
 the intermediate host for the parasite of yellow fever. Since t he pu I >- 
 Heat ion of our preliminary note we have continued our invest L r : i ions. 
 especially as regards the means by which ellow fever is propagated 
 
 hi 
 
 from individual to individual, and as to the manner hi which h> 
 become infected with the contagium of this disease. The results 
 already obtained are so positive and striking that, with the permis- 
 sion of Surg. Gen. Steinberg, we have concluded to present to this 
 congress an additional note, in which we will record the-e 
 observations. We desire to here express our sincere thanks t<> the 
 military governor of the island of Cuba, Maj. Gen. Leonard \\oo.i. 
 United States Volunteers, without whose approval and assi-tame 
 these observations could not have been carriea out. 
 
 In order to exercise perfect control over the movements of those 
 individuals who were to be subjected to experimentation, and to 
 avoid any other possible source of infection, a location was selected 
 in an open and uncultivated field, about 1 mile from the town of 
 Quemados, Cuba. Here an experimental sanitary station waa e>iah- 
 Ii-hed under the complete control of the senior member of this board. 
 This station was named ( 'amp La/ear, in honor of our late colleague, 
 Dr. Jesse W. Lazear, acting assistant surgeon, Tinted State 
 who died of yellow fever, while courageously investigating the 
 
 causation <f this disease. The site selected was very well drained, 
 freely exposed to sunlight and winds, and, from every point of \ iew, 
 satisfactory for the purpose intended. 
 
 > Rd At the Pan Am. Med. Cong., held In Hftbtna, Cube, Feb. 4-7, 1901. 
 
 '1'hllA.lUd.Joir 1900? 
 
 70 
 
YELLOW FEVER. 71 
 
 The personnel of this camp consisted of two medical officers, Dr. 
 Roger r. Ames, acting assistant surgeon, United States Army, an 
 immune; in immediate charge; Dr. R. P. Cooke, acting assistant 
 surgeon, United States Army, nonimmune; one acting hospital 
 steward, an immune; nine privates of the hospital corps, one of wnom 
 was immune; and one immune ambulance driver. 
 
 For the quartering of this detachment, and of such nonimmune 
 individuals as should be received for experimentation, hospital tents, 
 properly floored, were provided. These were placed at a distance of 
 about 20 feet from each other, and were numbered 1 to 7, respectively. 
 
 Camp Lazear was established November 20, 1900, and from this 
 date was strictly quarantined, no one being permitted to leave or 
 enter camp except the three immune members of the detachment 
 and the members of the board. Supplies were drawn chiefly from 
 Columbia Barracks, and for this purpose a conveyance under the con- 
 trol of an immune acting hospital steward, and having an immune 
 driver, was used. 
 
 A few Spanish immigrants, recently arrived at the port of Habana, 
 were received at Camp Lazear, from time to time, while these observa- 
 tions were being earned out. A nonimmune person, having once left 
 this camp, was not permitted to return to it under any circumstances 
 whatever. 
 
 The temperature and pulse of all nonimmune residents were care- 
 fully recorded three times a day. Under these circumstances any 
 infected individual entering the camp could be promptly detected and 
 removed. As a matter of fact only two persons, not the subject of 
 experimentation, developed any rise of temperature; one, a Spanish 
 immigrant, with probably commencing pulmonary tuberculosis, who 
 was discharged at the end of three days; and the other, a Spanish 
 immigrant, who developed a temperature of 102.6 F. on the after- 
 noon of his fourth day in camp. He was at once removed with his 
 entire bedding and baggage ana placed in the receiving ward at Colum- 
 bia Barracks. His fever, which was marked by daily intermissions 
 for three days, subsided on the administration of cathartics and ene- 
 mata. His first attack was considered to be due to intestinal irrita- 
 tion. He was not permitted, however, to return to the camp. 
 
 No nonimmune resident was subjected to inoculation who had not 
 passed in this camg the full period of incubation of yellow fever, with 
 one exception, to be hereinafter mentioned. 
 
 OBSERVATIONS. 
 
 Having thus sufficiently indicated the environment of Camp 
 Lazear and the conditions under which its residents lived, we wifi 
 now proceed to a narration of the observations thus far made at this 
 experimental station. At the time these inoculations were begun, 
 the several tents were occupied as follows: Tent No. 1 by one im- 
 mune and one nonimmune; No. 2 by one immune and two non- 
 immunes; No. 3 by two immunes; No. 4 by three nonimmunes; 
 No. 5 by three nonimmunes; No. 6 by two nonimmunes; and No. 7 
 by one nonimmune. 
 
 For the purpose of experimentation, subjects were selected as 
 follows: From tent No. 2, two nonimmunes, and from tent No. 5, 
 three nonimmunes. Later, one nonimmune in tent No. 6 was also 
 designated for inoculation. 
 

 
YKLLOW I'KVKK. 
 
 7:: 
 
74 YELU)W 
 
 CM* /. Pvt. John R. Kissinger, Hospital Corps, United States Army, aged 
 nonimmune, occupant of tent No. 2, with his full consent. was bitten ai 10 .:>o a. in.. 
 November 20, 1900, by a mosquito (C. fcuciatut) that had bitten a sever 
 yellow fever on the fifth day, 11 days previously; another severe case, on the third 
 day, 6 days before; and a third severe one on the third day, 3 days before. As Kissinger 
 had not absented himself from Columbia Barracks for a period of more than 30 da 
 was considered safe to inoculate him without waiting tor his period of incubation to 
 
 November 23 t 1900, Kissinger was again bitten by the same mosquito The result 
 of both inoculations was negative. The mosquito, therefore, was incapable 
 ing any infection on the eleventh or fourteenth day after it had bitten a severe case 
 of yellow fever on the third day of the disease. This insect had been kept at . >n 1 
 room temperature and died November 26. 1900. 
 
 Decembers. 1900. at 2 p. m. , 12 days after the last inoculation, Kissinger was again 
 bitten by o mosquitoes (C.fasciatu*), 2 of which had bitten fatal cases ..f \-ll..\\ 
 1 the second day, 15 days before: 1 a severe case on the second day, 19 d i-l\. 
 
 and 2 a mild case on the third day. 21 days b. 
 
 Thereraixloftemiyratureandpufo.^^ 
 
 showed that the n tuv*fr ^"TMP^fl IP fl la 1 V n Uftl "^te of DQMth dyjipg ' 
 days, except that OP f><vynnhftrH | nn ttift thit*r day ~Kiaingttr h^/) BiM^JMMpJflMMI 
 rising, which soon passecj away. At 4.30 p. m. commencement ot fourth foy -he 
 complained of frontal headache; otherwise he felt well ami partook of supper with 
 appetite; at 9 p. m., temperature was 98.4 F.. pulse 90; at 1 !.:;<> p m lie 
 with a chill, his temperature 100 F., pulse 90; he complained of severe frontal head 
 
 jecled a'l 
 
 ache ajiorTOc^acn^fnireyeTwere injecTeTTand his fa -e .-uiTui-ed. 
 
 a. m., his temperature was 102^. , pulse 102; he had violent hea 
 
 with nausea ana vomiungi He was then removed to the yell 
 
 subsequent history was that of a case of yellow fever at moderat 
 
 appeared in the urine on the fourth day/im-rea-ed |,,,,ne-lifth l. 
 
 day, and disappeared on December 22. Granular casts were pr 
 
 numbers' from the fourth to the eighth day" Th ConJVP ct 4Yff w 
 
 third day. The diagnosis of yellow fever in this case was made by Drs 
 
 Carles Finlay. \V. (\ Gorgas, and A. Diaz Allertini. the'board of yell 
 
 of the city of Habana, who saw the patient on several occasions during his illness. 
 
 Chart I.) The period of incul>at ion in this case was 3 days, 9J hours. 
 
 Case 2. John J. Moran, ag^ed 24, an American, nonimmune, occupant >f tent 
 with his full consent, was bitten at 10 a. m., November 26, 1900, by a m.^,ju; 
 faaciatus) which 12 days before had bitten a case of yellow fever of moderate se , 
 on the third day of the disease. This insect had also bitten a well -marked case of 
 yellow fever second day 10 days previously. 
 
 November 29, at 2.20 p. m., Moran was again bitten by the same mosqu 
 result of both of these inoculations was negative. This insect was the: pa Me 
 
 of conveying the infection 15 days after having bitten a case of yell<.\\ fever . i mod- 
 erate severity on the third day, and 13 days after it had liitten a well-marked case of 
 this disease on the second day. This mosquito had been kept a .ture. 
 
 Moran 's case will be again referred to when we come to speak of the im 
 building by means of contaminated mosquitoes. 
 
 CaseS. A Spanish immigrant, aged 26, a nonimmune occupant oft with 
 
 his full consent, was bitten at 4 p. m., Decembers, 1900, by 4 mosquitoes ( i 
 which had been contaminated as follows: One by biting a fatal case of yel 
 on the third day, 17 days before; 1 a severe case, on the third day, 18 day 
 a severe case, on the second day, 22 days before, and 1 a case of moderate -e\erit\ . 
 on the third day, 24 days previously. 
 
 The record of temperature and pulse, taken every3 hours after the ino< ulati. m. >hows 
 no rise of temperature above 99 F. until (i p. m.. De.eml.er l.; ..n the MXII 
 when 99.4 F. is recorded; pulse, 68. The Hiibjeet. who was of a very lively disposi- 
 tion, retained his usual spirits until noon of the 13th, although he complained oi 
 frontal headache on the llth and 12th. He took to his bea at noon of the I ::ih. the 
 fifth day, complaining of increased frontal headache and a sense of 
 p. m., his temperature was 98.2 F., pulse 62. 
 
 December 14, at 6 a. m., temperature was 98 F., pulse 72, and he still < 
 of frontal headache and general malaise. Profuse epistaxis occurred at 7.45 a. m. ; at 
 9 a. m., temperature was 99.6 F., pulse 80; at 1.15 p. m., temperature was 100 F., 
 
 .10 p. m., temperature juu./- r ., pulse OB; nis lace nusnea ana eye- 
 removed to the yellow-fever warns. A trace of albumin was found in the urine 
 
YELLOW FEVER. 75 
 
 passed at 3.30 p. m., December 15; a few hyaline cases were present. He was seen 
 at this time by the Habana board of experts, and the diagnosis of mild yellow fever 
 confirmed. (See Chart No. 2.) 
 
 The period of incubation in this case was 4 days and 24 hours, counting from the 
 time of inoculation to the hour when the patient took to his bed; if reckoned to the 
 onset of fever, it was 5 days and 17 hours. 
 
 Case 4. A Spanish immigrant, aged 27, a nonimmune occupant of tent No. 5, 
 with his full consent, was bitten at 10 a. m. November 26, 1900, by a mosquito (C. 
 fasdatus) which had bitten a severe case of yellow fever on the second day 10 days 
 before. Three days later, November 29, he was again bitten by the same insect. 
 December 2, after an interval of 3 days, he was again bitten by the same insect, 
 and also by a second mosquito ( C. fasdatus) which 12 days before had been con- 
 taminated by biting a fatal case of yellow fever on the third day. No unfavorable 
 effects followed any of these attempted inoculations. The first-mentioned mosquito, 
 therefore, was incapable of conveying any infection on the seventeenth day after 
 biting a severe case of yellow fever on the second day; the other also failed to infect 
 on the % twelfth day after biting a fatal case of yellow fever on the third day. Both 
 of these mosquitoes had been kept at ordinary room temperature. 
 
 December 9, after an interval of 7 days, the subject was again bitten, at 10.30 a. m., 
 by 1 mosquito (C. fasdatus) which had been infected 19 days before by biting a 
 fatal case of yellow fever on the second day of the disease. He remained in his usual 
 health until 9 a. m. December 12, the third day, when he complained of frontal 
 headache; his temperature was 98.8 F., pulse 96. This headache continued during 
 the entire day. At 6 p. m. temperature was 99 F., pulse 94; at 9 p. m. tempera- 
 ture 99 F., pulse 84; at 9.30 p. m. temperature 99.4 F., pulse 82. Severe head- 
 ache and backache was complained of; his eyes were injected and his face suffused. 
 The following morning he was sent to the yellow-fever wards. Urine passed at 4.20 
 p. m. December 15, the third day, gave a distinct trace of albumin. Many hyaline 
 casts were present on the same date. The conjunctives were jaundiced on the third 
 day. 
 
 The patient was seen by the board of experts on December 14 and the diagnosis 
 of yellow fever made. (See Chart No. 3.) 
 
 The period of incubation in this case was 3 days 11$ hours. 
 
 Case 5. A Spanish immigrant, aged 26, a nonimmune occupant of tent No. 5, 
 with his full consent, was bitten at 10 a. m. November 26, 1900, by a mosquito (C. 
 fasdatus) that had bitten a well-marked case of yellow fever on the third day 12 
 days before. November 29 he was again bitten by the same insect. December 2 
 he was for the third time bitten by 2 mosquitoes (C. fasdatus), beth of which had 
 bitten a well-marked case of yellow fever on the third day, 18 days before. As no 
 bad results followed any of these inoculations, it follows that these mosquitoes were 
 incapable of conveying any infection 18 days after they had bitten a well-marked 
 case of yellow fever on the third day. Both of these insects had been kept at room 
 temperature. 
 
 December 11, after an interval of 9 days, the subject was again, at 4.30 p. m., bitten 
 by the same mosquitoes, 4 in number, that had been applied to case 3 three days prior 
 to this time, with positive results. 
 
 The record of temperature and pulse, taken every 3 hours following the inoculation, 
 showed no change till December 13, the second day, at 9 a. m., when the temperature 
 was 99 F., and the pulse 78. From this hour till 6 p. m. the temperature varied from 
 99.2 to 99.6 F. The subject complained of frontal headache, slight in degree, 
 during the entire day. At 9 p. m. his temperature was 98.4 F., pulse 62. 
 
 December 14, the third day, he complained of slight frontal headache during the 
 entire day, and was indisposed to exertion. From 6 a. m. to 6 p. m. the temperature 
 averaged 99.2 F. , and the pulse varied from 64 to 90; at 9 p. m. it was 98.4 F. , the pulse 
 78. December 15, the fourth day, at 6 a. m. temperature was 98.2 F., pulse 78. 
 He still had frontal headache. At 9 a. m. temperature was 99.2 F., pulse 80; at 12, 
 noon, the former was 99.2 F., the pulse 74. The subject now went to bed, complaining 
 of headache and pains throughout the body. At 2 p. m. the temperature was 100 F., 
 the pulse 80; eyes much congested; face flushed. At 6 p. m. his temperature had risen 
 to 102 F., and the pulse to 90. He was then transferred to the yellow fever wards. 
 Albumin appeared in the urine at 7.30 a. m., December 17. Bleeding from the gums 
 and roof of the mouth occurred on the sixth and seventh days of his illness. 
 
 The case was examined by the board of experts on the 16th and 19th, and the diag- 
 nosis of yellow fever made. 
 
 Albumin disappeared on the sixth day, the temperature falling to normal on this 
 date, and remaining near this point till December 23, the ninth day of sickness, 
 when a relapse occurred, attended with bleeding from the gums on December 24 
 

 
YELLOW FEVER. 
 
 77 
 
78 
 
 YELLOW 
 
YELLOW FEVER. 
 
 79 
 
80 
 
 and 25, with the appearance of red blood cells and pus !!< in tho urine in moderate 
 numbere. Fevereuoeided on December 26, and the urine became normal on Decemlu>r 
 29. (See Chart 
 
 The period of incubation in this case, if reckoned from the time of inoculation to 
 the hour when the patient took to his bed, was 3 days, 19$ hours. 
 
 The four patients whoso histories we have above w. 
 
 examined_by anumbcr f ph\ --iciansof II .unong v may 
 
 mention u f <>. <>f ' ' Dr. S ; ; of "La 1> 
 
 fica,' 1 and J>r. Moas. of "La 1'n; all of \\honi 
 
 the diagnosis of yellow fever >yas confirmed. : rapidly 
 
 revie instances an end i- d yellow 
 
 fever, in order to emph.-i- be of interest and im: 
 
 nnection with tfieir occurrence. (\Ve omit any o the 
 
 clinical histories.) 
 
 It should he borne in mind that at the time when these inoculations 
 
 :m there were only l'J nouimmune n < 
 
 and that 5 of tlu^e v. !>e;-imeir 
 
 and 3 in tent No. 5. Of thoo \\e succeeded in infecting 1. vi/., 1 in 
 lent No. 2 and :> in tent No. A. each of whom developed . ,-k of 
 
 yellow fever within the period of incubation of this disease. The on 
 negative result, therefore, A\ -e 2 Moran inoculated \\ i 
 
 mosquito on the fifteenth day after the insect had ->o of 
 
 yellow fever on the third day. Since this moscjuito failed to infect 
 case 4, three days after it had hit ten Moran, it follow- th;it the ; 
 could not have been otherwise than negative in the ! We 
 
 now know, as the result of our observations, that in the case of an 
 i kept at room temperature during the cool weal her of November. 
 15 or even 18 days would, in all probability, be too short a tin 
 render it capable of producing the disease. 
 
 As bearing on the source of infection, we invite attention to the 
 period of time during which the subjects had been kept under riirid 
 quarantine, prior to successful inoculation, which was as foli 
 Case 1, 15 days; case 3, 9 days; case 4, 19 da 
 
 We further desire to emphasize the fact that this epidemic of yellow 
 fever, which affected 33.33 per cent, of the nonimmune resident 
 (amp Lazear, did not concern the 7 nonimmun's occupying ' 
 No. 1, 4, 6, and 7, but was strictly limited to th><e individuals who 
 had been bitten by contaminated mosquitoes. 
 
 Nothing could point more forcibly to the source of this infection 
 than the order of the occurrence of events at this camp. The 
 cision with which the infection of the individual followed the hi 
 the mosquito left nothing to be desired in order to fulfill the require- 
 ments or a scientific experiment. 
 
 The epidemic having ceased on December I.", r.uui. no other case 
 of vellov. occurred in this camp until we again began i 
 
 individuals to inoculation. Thus lo day- later \\e made t he i<>!lo\\ ing 
 observation: 
 
 Cote 6. A Spanish immigrant, aged 27, a nonimmune oocupam 
 his full consent, was bitten at 11 a. in . I :;0, 1900, by 4 mosquitoes (C fascia- 
 
 tiis) that had been contaminated 17 days pn-vi-m.-ly I mild case of yellow 
 
 on the fust day of the disease (case 4). These insects had been kept at a tem- 
 jMTaturo of S2 1 
 
 -inaincd in hi- normal condilion until the P\ !'()!. 
 
 the third day, when he complainH of frontal h< -a-l a- !] \t i j>. 
 wa99 F., pub*e64. ll> Lbutniill- d of headache on the foil 
 
 II" partook sparingly of breakfast, and afterwards lay < 
 
YELLOW FEVER. 81 
 
 being disinclined to exert himself. At 9 a. m., the temperature was 99 F., the pulse 
 96; at 10.30 a. m., temperature 100 F., pulse 80. A sense of chilliness and sharp 
 frontal headache was complained of, and at 3 p. m. his temperature was 100.8 F., his 
 pulse 89, and his eyes were congested and face flushed. He was removed to the 
 yellow-fever wards. A specimen of urine passed at midnight, January 4, contained a 
 distinct trace of albumin. Slight bleeding from the gums occurred on the fifth and 
 sixth days. The patient was seen by the board of experts on the second and seventh 
 days of his attack, and the diagnosis of yellow fever confirmed. (See Chart 5.) 
 
 The period of incubation in this case was 3 days. 22 hours. The subject had 
 remained in strict quarantine for 22 days preceding his inoculation. 
 
 In considering the character of the attacks and the course of the 
 disease in these five cases of experimental yellow fever, it must be 
 borne in mind that these infected individuals were all young men, in 
 good general physical condition and placed amid excellent hygienic 
 surroundings. Further, it must not be forgotten that, on the earliest 
 manifestation of an approaching infection, they were each and all put 
 to bed at once, and were even carried to the yellow-fever wards while 
 occupying the same bed. In other words, these men were kept at 
 absolute rest from the first inception of the disease. Just what bear- 
 ing this may have had on the subsequent course of the fever, we can 
 not say, but since so much stress is laid on absolute rest of the patient 
 by those having most experience in the treatment of yellow fever, the 
 influence of this enforced rest, in our case, upon the subsequent 
 course of the attack, was doubtless of much importance. We reserve 
 a consideration of the clinical side of these cases for a future report. 
 
 In our opinion, the experiments above described conclusively 
 demonstrate that an attack of yellow fever may be readily induced 
 in the healthy subject by the bite of mosquitoes (C.fasciatus) which 
 have been previously contaminated by being fed with the blood of 
 those sick with yellow fever, provided the insects are kept for a suffi- 
 cient length of time after contamination before being applied to the 
 person to be infected. 
 
 Our observations do not confirm Finlay's statement that the bite 
 of the mosquito may confer an abortive attack of yellow fever when 
 applied to the healthy subject 2 to 6 days after it has bitten a yellow 
 fever patient. We have always failed to induce an attack even of 
 the mddest description when we have used mosquitoes within less 
 than 12 days from the time of contamination, although the insects 
 were constantly kept at summer temperature. We could cite 
 instances where we have applied mosquitoes at intervals of 2, 3, 4, 
 5, 6, 9, and 11 days following the contamination of the insect with 
 the blood of well-marked cases of yellow fever early in the disease 
 without any effect whatever being produced by the bite. Thus in 1 
 case no result followed the bite of 14 mosquitoes which 4 days pre- 
 viously had been contaminated by biting a case of yellow fever on 
 the first day. Again, 7 days later, or 11 days after contamination, 
 the surviving 7 of these insects failed to infect an individual. On 
 the seventeenth day after contamination, however, the bite of 4 of 
 these mosquitoes all that remained of the original 14 was promptly 
 followed by an attack of yellow fever in the same individual. These 
 insects had been kept during the whole of this time at an average 
 temperature of 82 F. 
 
 Our observations would seem to indicate that after the parasite 
 has been taken into the mosquito's stomach, a certain number of 
 days must elapse before the insect is capable of reconveying it to man. 
 
 79965 S. Doc. 822, 61-3 6 
 
82 
 
 This period doubtless represent* the time required for the i>ara*ite 
 to pass from the inaect'fl stomach to it< salivary glands, ana would 
 
 appear to be about 1 in summer weather and moM probably 
 
 about 18 or more days during the cooler \\inter months It follows 
 also that our ohs,r\ at i>n- do nt cnnlirm Kinlay'* opinion that the 
 bite of the contaminated mosquito may confer immum isl a 
 
 subsequent attack of \ell..\\ In our experience an individual 
 
 mav he hit ten on three or more occasions by contaminated moM|ii 
 \\itliout manifesting an\ BJ mptoms of di-t urbancc to health, and yet 
 promptly si, -ken \\ith yellow fever within a fe\\ day- after being 
 hitten by an in-cct capahle of coim-yini: the infection. 
 
 IKIMI.N i u mi: in-KASE. 
 
 Having shown that yellow fever can he conveyed hy the hite of 
 an infected mosquito, it remain- to inquire whether this disease 
 can be acquired in any other manner. It has seemed to us that 
 vellow fever, like the several types of malarial fever, might he ind 
 'hy the injection of blood taken from the general circulation 
 natient sull'ering from this disease. Accordingly we- have subj. 
 tour individuals to this method of infection, with one i and 
 
 three positive results. Reserving the detailed description of 
 cases to a subsequent occasion, we may state that in one of the ; 
 live cases an attack of pronounced yellow fever followed the >ul>< -u- 
 taneous injection of 2 c. c. of blood taken from a vein at the bend of 
 the elbow on the first day of the disease, the period of incubation 
 being 3 days and 22 hours; in the second case, 1.5 c. c. of blood, t aken 
 on the first day of the disease and injected in the same manner, 
 brought about *an attack within 2 days and 12 hours: while in our 
 third case, the injection of 0.5 c. c. of blood, taken on the second day 
 of the disease, produced an attack at the end of 41 hours. 
 
 In the case mentioned as negative to the blood injection, the .sub- 
 sequent inoculation of this individual with mosquitoes already pi 
 to oe capable of conveying the disease, also resulted negat ively. \\V 
 think, therefore, that this particular individual, a Spanish immigrant, 
 may be considered as one who probably possesses a natural immunity 
 to yellow fever. 
 
 It is important to note that in the three cases in which the injection 
 of the blood brought about an attack of yellow fever, careful cultures 
 from the same blood, taken immediately after injection, failed to 
 show the presence of Sanarelli's bacillus. 1 
 
 Our observations, therefore, show that the parasite of yellow fever 
 i- present in the general and capillary circulation, at least during the 
 early stages of this disease, and that the latter may be conveyed, like 
 
 nalarial parasite, either hy means of the hite of the moxpii' 
 by the injection of blood taken from the general circulation. 
 
 1 A fourth case tf yellow fever, severe in type, has been produced by the subcutaneous injection 
 of blood taken from the general circul . eoond day of the disease, the period < 
 
 3 days and 1 hour. The patient from whom the blood was obtained was an experimental case which was 
 in turn produced bv the Injection of blood 0.5 c. c. derived from a nonexpert 
 fever. As "controls," oases 1, 4, 0, and 7 of this report were also injected subcutaneous I y v. 
 the Mine blood without manifesting any symptoms whatever. The blood which produced this 
 ca^e of yellow fever, when transferred at the same time to bouillon >u bes In considerable quantities, gave no 
 growth whatever. 
 
YELLOW FEVER. 83 
 
 CAN YELLOW FEVER BE PROPAGATED IN ANY OTHER WAY ? 
 
 We believe that the general consensus of opinion of both the medical 
 profession and the laity is strongly in favor of the conveyance of 
 yellow fever by fomites. The origin of epidemics, devastating in 
 their course, has been frequently attributed to the unpacking of 
 trunks and boxes that contained supposedly infected clothing; and 
 hence the efforts of health authorities, both State and National, are 
 being constantly directed to the thorough disinfection of all clothing 
 and bedding shipped from ports where yellow fever prevails. To 
 such extremes have efforts at disinfection been carried, in order to 
 prevent the importation of this disease into the United States, that 
 during the epidemic season all articles of personal apparel and bedding 
 have been subjected to disinfection, sometimes both at the port of 
 departure and at the port of arrival; and this has been done whether 
 the articles have previously been contaminated by contact with 
 yellow fever patients or not. The mere fact that the individual has 
 resided, even for a day, in a city where yellow fever is present, has 
 been sufficient cause to subject his baggage to rigid disinfection by 
 the sanitary authorities. 
 
 To determine, therefore, whether clothing and bedding, which 
 have been contaminated by contact with yellow fever patients and 
 their discharges, can convey this disease is a matter of the utmost 
 importance. Although the literature contains many references to 
 the failure of such contaminated articles to cause the disease, we have 
 considered it advisable to test, by actual experiment on nonimmune 
 human beings, the theory of the conveyance of yellow fever by 
 fomites, since we know of no other way in which this question can 
 ever be finally determined. 
 
 For this purpose there was erected at Camp Lazear a small frame 
 house consisting of one room 14 by 20 feet, and known as " Building 
 No. 1" or the "Infected clothing and bedding building." The cubic 
 capacity of this house was 2,800 feet. It was tightly ceiled within 
 with "tongue and grooved" boards, and was well battened on the 
 outside. It faced to the south and- was provided with two small 
 windows, each 26 by 34 inches in size. These windows were both 
 placed on the south side of the building, the purpose being to prevent, 
 as much as possible, any thorough circulation of the air within the 
 house. They were closed by permanent wire screens of 0.5 mm. 
 mesh. In addition sliding glass sash were provided within and heavy 
 wooden shutters without ; the latter intended to prevent the entrance 
 of sunlight into the building, as it was deemed undesirable that the 
 disinfecting qualities of sunlight, direct or diffused, should at any 
 time be exerted on the articles of clothing contained within this room. 
 Entrance was effected through a small vestibule, 3 by 5 feet, also 
 placed on the southern side of the house. This vestibule was pro- 
 tected without by a solid door and was divided in its middle by a 
 wire screen door, swung on spring hinges. The inner entrance was 
 also closed by a second wire screen door. In this way the passage 
 of mosquitoes into this room was effectually excluded. During 
 the day, and until after sunset, the house was kept securely closed, 
 while by means of a suitable heating apparatus the temperature was 
 raised from 92 to 95 F. Precaution was taken at the same time to 
 maintain a sufficient humidity of the atmosphere. The average 
 
84 YELLOW FEVEB. 
 
 temperature of this house was thus kept at 76.2 K. for a period 
 of 63 days. 
 
 November .'U). I'MHt. the building now being ready for occupancy. 
 three large boxes filled \\i\\\ sheets, pillow slips, hlankt con- 
 
 taminated by contact with rases of yelh 
 were rec :id placed th- > of tin- 
 
 been taken from the beds of patients sick with 
 Animas Hospital, Ilabana, or at Columbia Barm hem 
 
 had hecii purposely soiled with a liberal quantity of black vomit, 
 urine, and fecal matter. A dirty " comfortable" and muc!i-M>ilcd 
 of blankets, removed from the bed of a patient sick \\\\\\ yellow 
 : in the to\\ n of Quemados, were contained in one of these Do 
 The same day, at 6 p. m., Dr. R. P. Cooke. a< 1 1 mt sm 
 
 United States Army, and two privates of the Hospital Corps, all ; 
 immune young Americans, entered this building and dc! 
 unpacked' these boxes, which had been tightly cl 
 a period of two weeks. Thev were careful at the same tim 
 each article a thorough handling and shaking in onl 
 through the air of the room the specific agent of yell 
 tained in these fomites. These soiled sheets. nillo\\ 
 blankets were used in preparing the beds in which the me 
 the Hospital Corps slept. Various soiled artiel. >und 
 
 the room and placed about the bed occupied by Dr. 
 
 From this date until December 19, 1900, a series of 'J ihis 
 
 room was occupied each night by these three nonimmunes. ! 
 morning the various soiled articles were carefully packed in the ai 
 said boxes, and at night again unpacked and distributed about the 
 room. During the day the residents of this house were permit t . 
 occupy a tent pitched in the immediate vicinity, but were kept in 
 strict quarantine. 
 
 December 12, a fourth box of clothing and bedding v ived 
 
 from Las Animas Hospital. These articles had been UMM| on the beds 
 of yellow-fever patients, but in addition had been pur; >iled 
 
 with the bloody stools of a fatal case of this disea box 
 
 had been packed for a number of days, when opened and unpa 
 by Dr. Cooke and his assistants, on 'December 1J. the odor \\ 
 offensive as to compel them to retreat from the hou>e. They piuckilv 
 returned, however, within a short time and spent tl 
 
 December 19, these three nonimmunes were placed in quarantine 
 for 5 days and then given the liberty of the camp. All I, med 
 
 in perfect health, notwithstanding their stay of 20 nigh 
 unwholesome surroundings. 
 
 During the week, December 20- -7. the following articles were also 
 placed in this house, viz: Pajama suits, 1 : under>hii 
 4; pillow slips, 4; sheets, 6; bl;, 5; pillov 
 
 These article- had been removed from the perx.ns and bed- of four 
 patients sick with yellow fe\er and were \ ery much soiled, a-- 
 change of clothing or bed linen during their attacks had been pur- 
 posely avoided, the object bein^ to obtain articles as thoroi: 
 contaminated as possible. 
 
 om December 21, 1900, till January 10, 1901. this building was 
 again occupied by two noninunune youn under i 
 
 conditions as the preceding occupants, except that these men slept. 
 
YELLOW FEVER. 85 
 
 every night in the very garments worn by yellow-fever patients 
 throughout their entire attacks, besides making use exclusively of 
 their much-soiled pillow slips, sheets, and blankets. At the end of 
 21 nights of such intimate contact with these fomites, they also went 
 into quarantine, from which they were released 5 days later in per- 
 fect health. 
 
 From January 11 till January 31, a period of 20 days, "Building 
 No. 1" continued to be occupied by two other nonimmune Amer- 
 icans, who, like those who preceded them, have slept every night in 
 the beds formerly occupied by yellow-fever patients and in the night- 
 shirts used by these patients throughout the attack, without change. 
 In addition, during the last 14 nights of their occupancy of this house, 
 they have slept, each night, with their pillows covered with towels 
 that had been thoroughly soiled with the blood drawn from both the 
 general and capillary circulation, on the first day of the disease, in 
 the case of a well-marked attack of yellow fever. Notwithstanding 
 this trying ordeal, these men have continued to remain in perfect 
 health. 
 
 The attempt which we have therefore made to infect "Building 
 No. 1 " and its 7 nonimmune occupants, during a period of 63 days, 
 has proved an absolute failure. We think we can not do better here 
 than to quote from the classic work of La Roche. 1 This author says: 
 
 In relation to the yellow fever, are find so many instances establishing the fact of the 
 nontransmissibliity of the disease through the agency of articles of the kind mentioned, 
 and of merchandise generally, that we can not but discredit the accounts of a contrary 
 character assigned in medical writings, and still more to those presented on the strength 
 of popular report solely. For if in a large number of well authenticated cases such 
 articles have been handled and used with perfect impunity and that, too, often under 
 circumstances best calculated to insure the effect in question we have every reason 
 to conclude that a contrary result will not be obtained in other instances of a similar 
 kind, and that consequently the effect said to have been produced by exposure to tnose 
 articles must unless established beyond the possibility of doubt be referred to some 
 other agency. 
 
 The question here naturally arises: How does a house become 
 infected with yellow fever ? This we have attempted to solve by 
 the erection at Camp Lazear of a second house, known as "Building 
 No. 2," or the "Infected mosquito building.'' This was in an 
 respects similar to "Building No. 1," except that the door and 
 .windows were placed on opposite sides of the building so as to give 
 through-and-through ventilation. It was divided, also, by a wire- 
 screen partition, extending from floor to ceiling, into two rooms, 
 12 by 14 feet and 8 by 14 feet, respectively. Whereas, all articles 
 admitted to "Building No. 1" have been soiled by contact with 
 yellow-fever patients, all articles admitted to "Building No. 2" were 
 first carefully disinfected by steam before being placed therein. 
 
 On December 21, 1900, at 11.45 a. m., there were set free in the 
 large room of this building 15 mosquitoes (O.fasciatus) which had 
 previously been contaminated by biting yellow -fever patients, as 
 follows: One, a severe case, on the second ^day, November 27, 1900, 
 24 days; 3, a well-marked case, on the first day, December 9, 1900, 
 12 days; 4, a mild case, on the first day, December 13, 1900, 8 days; 
 7, a well-marked case, on Mie first day, December 16, 1900, 5 days 
 total, 15. 
 
 iR. La Roche: Yellow Fever, Vol. II, p. 516, Philadelphia. 
 
86 
 
 Only one of these in-- idered capable of conveying the 
 
 infection, vi/. the mosquito that had bitten a se\ ere case -1 days 
 before, while 3 others tin* U-day inseets--had possibly reached the 
 dangerous stage, as thev had been kept at an average temperature 
 
 At U M. of the same day. .llm .1. Moran already referred to 
 186 - in this report, a nonimmnne American, entered the room 
 where the mo^jtiitn^ had heen freed and remained .SO minute. 
 During this time lie was hit ten about the fa -e and hands b; 
 
 p. in., the same day. he ntered and remained 
 
 JO minutes, and was again bitten. The followin >, m.. 
 
 he, for the third time, entered the room and was again bitten. 
 
 Ca*e7. -On 1' 25. 1900, at 6 a. m., the fourth day. M..ran . ..m|. I. lined of 
 
 slight dizziness and frontal headache. At II a. in. ho went to bed, complain 
 increased headache and malaiae, with ft temperature of 99.6 I-'.. pulse 88; at no 
 .temperature was 100.1 F.. the pulse 98; at 1 p. m., 101.2 F.. ih<- j ttd his 
 
 eyes were much injected and face suffused. He was removed t ih- y-ll..\v 
 wards. He was seen on several occasions by the board of experts and the diagnosis of 
 ycll<.\v fryer confirmed. (See Chart 6.) 
 
 The period of incubation in this case, dating from the first vi>ii to 
 "Building No. 2," was 3 days and 23 hours. If reckoned from his 
 last visit it was 2 days and 18 hours. Then* was no other possible 
 source for his infection, as he had been strictly (piarantined at Camp 
 Lazear for a period of 32 days prior to his exposure in the mosquito 
 building. 
 
 During each of Moran's visits, two nonimmunee remained in 
 same buSdinjr, only protected from the mosquitoes by i be \\ ire-eci 
 partition. From December 21, 1900, till January 8, 1901, inclusive 
 18 nights these nonimmunes have slept in this house, only pi 
 by the wire-screen partition. These men have remained in perfect 
 health to the present time. 
 
 December 'JS after an interval of 7 days, this house was a^ain 
 entered by a nonimmune American, who remained _!."> minutes. The 
 subject was bitten by only one insect. The following day he a 
 entered and remained 15 minutes, and was apiiu bitten by 
 mosquito. The result of these two visits was entirely n As 
 
 the mortality among the insects in this room, from some unknown 
 cause, had been surprisingly lanjv. it i- po>-ible that tln'Mihjeci 
 bitten by insects not more than 13 days old, in which case they would 
 probably not infect, since they had been kept for only "> days at a tem- 
 perature of 82 F., and for 8 days at the mean temperature ,,f the 
 room, 78 F. 
 
 Be this as it may, nothing can be more .striking or in>tructivo as 
 bearing upon the cause of house infection in yellow fever than when 
 we contrast the results obtained in our attempts to infect Buildings 
 No. 1 and No. 2j for whereas in the former all of 7 nnnimm 
 escaped the infection, although < to the most intimate contact 
 
 with the fomites for an aver;i d of 21 night inthel 
 
 an ( kerned by as many minutes, was quite sull'n-ient to 
 
 give an attack of yellow rever to one out of two persons who entered 
 the building ."( pel cent. 
 
 Thus, at Camp La/ear, of 7 nonimmunes whom we attempted to 
 infect by means of the bites of contaminated mosquitoes, \\e have 
 succeeded in conveying the di case to 6, or 85.71 per cent. On the 
 
YELLOW FEVER. 87 
 
 other hand, 7 nonimmunes whom we tried to infect by means of 
 fomites, under particularly favorable circumstances, We did not 
 succeed in a single instance. Out of a total of 18 nonimmunes whom 
 We have inoculated with contaminated mosquitoes since we began 
 this line of investigation, 8, or 44.4 per cent, have contracted yellow 
 fever. If we exclude those individuals bitten by mosquitoes that 
 had been kept less than 12 days after contamination, and which Were, 
 therefore, probably incapable of conveying the disease, we have to 
 record 8 positive and 2 negative results 80 per cent. 
 
 CONCLUSIONS. 
 
 1. The mosquito (C. fasciatus] serves as the intermediate host for 
 the parasite of yellow fever. 
 
 2. Yellow fever is transmitted to the nonimmune individual by 
 means of the bite of the mosquito that has previously fed on the 
 blood of those sick with this disease. 
 
 3. An interval of about 12 days or more after contamination 
 appears to be necessary before the mosquito is capable of conveying 
 the infection. 
 
 4. The bite of the mosquito at an earlier period after contamina- 
 tion does not appear to confer any immunity against a subsequent 
 attack. 
 
 5. Yellow fever can also be experimentally produced by the sub- 
 cutaneous injection of blood taKen from the general circulation 
 during the first and second days of this disease. 
 
 6. An attack of yellow fever, produced by the bite of the mosquito, 
 confers immunity against the subsequent injection of the blood of an 
 individual suffering from the nonexperimental form of this disease. 
 
 7. The period of incubation in 13 cases of experimental yellow 
 fever has varied from 41 hours to 5 days and 17 hours. 
 
 8. Yellow fever is not conveyed by fomites, and hence disinfection 
 of articles of clothing, bedding, or merchandise, supposedly contam- 
 inated by contact with those sick with this disease, is unnecessary. 
 
 9. A house may be said to be infected with yellow fever only when 
 there are present within its walls contaminated mosquitoes capable 
 of conveying the parasite of this disease. 
 
 10. The spread of yellow fever can be most effectually controlled 
 by measures directed to the destruction of mosquitoes and the pro- 
 tection of the sick against the bites of these insects. 
 
 11. While the mode of propagation of yellow fever has now been 
 definitely determined, the specific cause of this disease remains to be 
 discovered. 
 
 DISCUSSION. 
 
 Dr. Louis Perna, Cienfuegos, Cuba, in opening the discussion, said 
 that it is sophism to believe that post hoc, ergo propter hoc; that is to 
 :say, that, as Carmona, Freire, banarelli, and others have fallen to 
 this error, we must not be too precipitate in accepting the result 
 'of statistics. The studies made of mosquitoes are very old. A 
 French physician, who died about 1850, expressed the opinion that 
 malaria, yellow fever, and cholera were propagated by mosquitoes. 
 Dr. Perna also criticized the methods employed by the commission 
 
88 
 
 in making experiments on human beings and is entirely . >pj>o>ed to 
 aud 
 
 Dr. San Mai'tin eloquently defended, and with strong arguments, 
 the high scientific standard of the expeiimei iried out by this 
 
 commission, and also brought out the point that it was not stati 
 but facts that this commission presented. 
 
 Or. II. B. lloilbeck. Charleston. S. ( ' . expressed hi- opinion that 
 the problem of 200 years was about to be solved, that the old quar- 
 antine regulations should be greatly modified. He al ibed 
 the e of a pine belt Within a short distance of Charleston. 
 S. C., ill which yellow fever never developed as an epidemic, although 
 the afllicted therewith would go there during the existence of the 
 epidemic in Charleston, would die from the disease, and \ t it \\nuld 
 not spread. Mosquitoes are not known in that region, and probably 
 this is the true cxph.nat ion of the above fact. Me concluded by 
 emphasizing the inestimable value of these cxpeiimcnts if they i 
 to be true. 
 
 Dr. Emilio Marline/.. Ilabana, laid emphasis nn Dr. San Martin's 
 V10W8, lb v took up the moral question and claimed that \\ithout 
 these no truth could have been found. 
 
 Dr. Manuel (iutierre/.. Mexico, who up to within a short time had 
 been adverse to the theory of the transmission of this di-c ;: -e by 
 mosquitoes, now accepted as incontrovertible the results of the experi- 
 ments of the commission. He followed with interest many of the 
 experiments, and as a member of the commission saw n 
 cases, which he had no hesitation in pronouncing typical ca- 
 yellow fever. A fact which impressed him forcibly was the absolute 
 control of the epidemic by Dr. Reed. The cases would develop or 
 not, as he wished. He does not think that the mosquito should be 
 called the Culex fasciatus. Giles's description of the ('///*./ tiniads 
 mosquito agrees more closely than with the Culex fasciatus. He 
 describes the difference between them. He is inclined to consider 
 them a genus apart because they lay different eggs. 
 
 Dr. C. Finlay, Habana, expressed his admiration for the work of 
 the commission. He believes that this session of the con II go 
 
 down in history as of great importance 4 and that the di 
 between his opinion and that held by ihe commission will d 
 in the course of time. He states that they were based on the fact 
 that he investigated with three varieties of mosquitoes. \\l.iie the 
 commission has been restricted to one variety; that the b. 
 placed on better footing for obtaining s the 
 
 negative result obtained by the inocula'ion of mosqiiitoo. of short 
 infection should not induce the commission or the board to make 
 such bard and biased rules as are evidenced in its conclusion-. 
 
 Dr. Reed, in conclusion, said he was profoundly impre><ed with 
 the interest and attention given to these experiments. In rc'j-anl to 
 
 moral aspect of the Case, he did not think that an\ one api 
 the position in which he found himself the difficulties (h 
 his path. The first experiment \\ as made on a memberof the board, 
 Dr. Carroll. The senior member expected to i. bite in turn, 
 
 but was nnexpertedly called north. As no aniniid could \n> ;/iven 
 the disease, and it was useless to follow the previous indelinit 
 ments, it was absolutely nrcr^iiry to make tl rimerr 
 
 human subjects, or otherwi e rolumea -nuld have been and 
 
YELLOW FEVEE. 89 
 
 discussed, and yet we would have been no nearer the truth than at first. 
 No progress could have been made toward an exact knowledge of the 
 disease unless human subjects had been used. All experiments were 
 performed on persons who had given their free consent. 
 
 In reference to the remarks of Dr. Holbeck, of Charleston, the dis- 
 infection of vessels should by no means be dispensed with, but only 
 of such articles as bedding and clothing, though it is necessary to get 
 rid of the mosquitoes, and this simplified the process of disinfection. 
 
 In regard to the remarks of Dr. Gutierrez, in reference to the name 
 of the mosquito, Dr. Howard, of Baltimore, told him that Culex 
 fasciatus is identical with Culex tiniads as described by Giles. Theo- 
 bolt separates Culex tiniads from the genus Culex and places it in a 
 new genus, Stegamina. These lay their eggs in a peculiar way, and 
 there is also a difference in the anterior claws of the male insect from 
 those of the other Culex. There is also a difference in the larva of 
 the Culex fasciatus. It is very interesting also to note the fact that 
 this is the very mosquito that Dr. Finlay used in his experiments 
 and that this particular mosquito does not belong to the genus Culex; 
 therefore malaria has a genus of its own, Anopheles, and yellow fever 
 the genus Stegamina. 
 
CM MM Kit' 4. 
 
 THE PROPAGATION OF YELLOW FEVER OBSERVATIONS BASED 
 ON RECENT RESEARCHES.' 
 
 KB REED. M I> . Surgeon, Uniu-.i ay, 
 
 Mi: 1'Ki.Mi.r.M LOT <.I:MI.I:MKN OF THE I- ' \< i i n : If. upon 
 .;t of your kind invitation to ho present with you to-night my 
 first impulse \\as to decline. 1 beg that you will not attribute this 
 to any want of appreciation on my part of the honor conferred, hut 
 solely to my desire to avoid what 1 felt would he a very em h;. 
 position should 1 attempt to follow in the footsteps of the dis- 
 tinguished gentlemen whom you have invited to fill this position 
 from year to year. Kecogni/ing in them, as all willing leader 
 leaders in the profession, \\lio. hy their well-con-idcied addn 
 have been able to add so much to the scientific interest of your 
 annual meetings, I could hut 1W1 that the burden which you | 
 to put upon me was greater than I could bear. That. nevcrtheli-s. 
 I am here in the capacity of your annual speaker is due to my unwill- 
 ingness even to appear disobliging to this old ami honorable . 
 eiation of physicians, among whose number I find included 
 of my most valued friends; friends who in years gone by have laboied 
 so faithfully to instill into my mind the value of the scientific method. 
 but to whom I have been able to make such small ret inn. If, there- 
 fore, I drew some encouragement from the feeling that I should not 
 be wholly among strangers, I found yet more in the thought that 
 such an eminent body of physicians as this faculty must ever be 
 willing to welcome any contribution that promises to shed liirht 
 upon a subject hitherto enshrouded in darkness, and which tin- 
 holds out the prospect of an addition to our knowledge in the I 
 field of preventive medicine. 
 
 In the hope that what I have to say to-night may contribute to 
 the solution of a somewhat obscure problem, and may assist u< 
 hereafter in the struggle with a grave epidemic disease, I have con- 
 cluded to present for you i- consideration "The propagati* .-How 
 fever, based on recent researches." 
 
 Before proceeding to the discussion of this subject, it is fitting that 
 I should pay brief tribute to the memory of a former member of 
 thiv faculty.' the late Dr. Jesse NV- l-i/ear. I'niled States Arm \ 1 
 can hardly trust myself to speak of my late colleague, since the men- 
 tion of his name brings hack Mich scenes of anxiety and dcpreion 
 as one ic, 'alls only with pain. Along \\ilh these sad mem. 
 however, come Other recollections of a manly and fearless devotion 
 to duty sued as I have never seen equaled. In the disci 
 the latter. Dr. Lazear seemed absolutely tireless and quite ol>li\ 
 
 ' A-HP-SS d '.' on.- hundn-d !in .l third ami I "f the Medical and Chlrurgical 1 
 
 Of the Stete o( Maryland. . 
 
 90 
 
YELLOW FEVER. 91 
 
 of self. Filled with an earnest enthusiasm for the advancement of 
 his profession and for the cause of science, he let no opportunity 
 pass unimproved. Although the evening might find him discouraged 
 over the difficult problem at hand, with the morning's return he 
 again took up the task full of eagerness and hope. During a service 
 of less than one year in Cuba he won the good will and respect of 
 his brother officers and the affection of his immediate associates. 
 Almost at the beginning of what promised to be a life full of usefulness 
 and good works he was suddenly stricken, and, dying, added one 
 more name to that imperishable roll of honor to which none others 
 belong than martyrs to the cause of humanity. 
 
 It is my own earnest wish that, whatever credit may be hereafter 
 given to the work of the American commission in Cuba during the 
 past year, the name of my late colleague, Dr. Lazear, may be always 
 associated therewith. 
 
 I do not propose to set before you this evening so much the views 
 of others in relation to the etiology of yellow fever, or to the conditions 
 under which it originates and spreads, as to give you the results of 
 my own experience with regard to the manner in which this disease 
 propagates itself. In the ordinary course of Army administration, I 
 found myself brought in contact with yellow fever during the sum- 
 mer of 1900, under such circumstances as permitted me to give my 
 entire time to the study of its etiology and propagation. Permit me 
 here to remark that so many claims have been made as to the specific 
 cause of yellow fever claims that could not be confirmed by other 
 investigators that one must needs feel considerable hesitancy in 
 considering this remarkable disease from any aspect. I must con- 
 fess that I have experienced, in the highest degree, this feeling of 
 reluctance to write or speak about yellow fever, especially when I 
 recall the frame of mind of myself and my colleagues that of utter 
 perplexity and wonder as we stood by the bedside of patients, or at 
 the autopsy table of those who had died of this mysterious malady. 
 I trust, therefore, that whatever I may say here to-night will be 
 considered as a modest expression of opinion growing out of an 
 unprejudiced study of yellow fever, for the most part from the point 
 of view of its propagation. 
 
 Although considerable attention had been given to the laboratory 
 study of the microorganisms isolated by Sternberg and Sanarelli 
 from the organs of yellow-fever cadavers, this did not enable one to 
 form any opinion concerning the nature of the disease or the mode 
 of its propagation. 
 
 At the time of our arrival in Cuba June, 1900 the situation as 
 regards the etiology of yellow fever may be briefly stated as follows : 
 The claims of all investigators for the discovery of the specific agent 
 of this disease had been disproved by the exhaustive work of Stern- 
 berg/ published in 1890, except that made by Dr. Sanarelli, in June, 
 1897, for his bacillus icteroides. I need not take up time here with 
 mention of those who had investigated Sanarelh's claim, except to 
 state that the confirmation of his discovery came chiefly from workers 
 in the United States, of whom 1 may speak of Achinard and Woodson, 
 of New Orleans, and especially of Wasdin and Geddings, of . the 
 
 i Keport on the Etiology and Prevention of Yellow Fever, 1890. 
 
92 
 
 Marine-Hospital 8 . in a report ' submitted duringthe 
 
 v.l in the full. laim for the 
 
 specific their confirmation on 
 
 tlit' finding of this bacillus in \ ellow te\ er studied 
 
 by them in the . ana. Under these circumstance 
 
 of the lir-t Unportknce that we should give our entire time to the 
 Search for tocuftlt *V/< nmA \ in the Indies of vellov, -fever eases. Tlu 
 result of this stu Jl cases during life and 1 1 auto] 
 
 and which has ah. Q in our 
 
 Preliminan hist meet in-: of the American Public 
 
 '0). 
 
 Turning for a moment to our knowledge concerning the mode of 
 of yellow fever, t he sit ua t i< .n . \\ hen .,:i WOlfe, was 
 
 about as follows: The battle for or air. importation ha\ 
 
 already deeided in favor of the former belief, its t ran-;i!i--i(>iiity from 
 nlace to place \vas attributed to the individual ull'ectcd by tin 
 but especially to his clothing; With the proviso. howcNer, that 
 intimately connected with its spread was involved a proper constitu- 
 tion of the atmosphere of the place, this latter due ehielly to in-ani- 
 tary conditions of soil. That the excreta of the patient contained 
 the specific agent of the disease was supported by many g<od authori- 
 ties. That the disease could be propagated by fomites was not de- 
 puted bv anyone. Against its spread by the sick and by fount t 
 quarantine measures were being then directed. 
 
 The theory of Finlay for the propagation of yellow fever by the 
 mosquito, concerning which I shall presently ha 
 had either gained no credence or been rejected by reason of the ah-' 
 of any results that had been presented by its author in support of it. 
 In tfie meantime, and before we had completed our search for 
 Sanarelli's bacillus, certain facts had been cropping out, as it \ 
 which served to arrest the attention. Just here, while mentioning 
 the first fact, let me say that one does not like to con) ignorance 
 
 of such a well-known disease as yellow fever, especially bcl'-i 
 audience some of whose members may have already treated cases 
 during the last epidemic in this city, in the year 1876; and yet candor 
 compels me to record my very great surprise, when brought fa< 
 face with yellow fever, to learn that attendance on patients by non- 
 immune nurses, in every stage of the malady, involved no danger. 
 In other word-, that yellow fever, both in the wards at Columbia 
 Barracks, a- well as in the wards of Las Aninia- Il<^pi; ; i|. Habana. 
 was not contracted by the attendants under circumstances such as 
 those in which typhoid fever and Asiatic cholera are too often c<m- 
 d. Further inquiry along this line seemed to indicate that the 
 disease had not been contracted in hospitals, even during the earlier 
 epidemic-, when disinfection of article- of clothing and bedding was 
 
 unknown. 
 
 ud fact which appeared worthy of note, uas the di-char 
 
 pa tii m- from the wards ouring early convalescence, and their i< 
 
 to the companion-hip of their comrades \\ith apparently no d; 
 of establishing fresh foci of the disease. This hardly seemed in 
 keeping u iih the pn lie agent in 1 1 ' a of the sick, 
 
 third fact which stood ui prominently \\as that, in certain of 
 
 our cases, no growth whatever was obtained on our present laboratory 
 
 i The Cause of Yellow Fever. Washington. 19M. 
 
 * Tbt Etiology of uinary Note, i'hll. Med. Journal, Oct. 27, 1900. 
 
YELLOW FEVER. 93 
 
 media, either by frequent cultures taken from the blood during life 
 or from the organs after death. In other words, no bacterium was 
 obtainable by aerobic methods, in certain of our cases, either during 
 life or after death. This result had considerable weight in controlling 
 our future work. 
 
 During the time that these cases were being studied, opportunity 
 was afforded to investigate an epidemic of fever 'which was prevailing 
 in Pinar del Rio Barracks, near the town of this name, distant 110 
 miles from Habana, and of which fever several soldiers, in a garrison 
 of about 900 men, had already died. A visit was made to this garrison 
 with my colleague, Dr. Agramonte, on the 31st day of July, 1900, 
 and a body sectioned the same afternoon. The lesions found were 
 those of yellow fever. Inquiry showed that under the diagnosis of 
 "remittent malarial fever" or "pernicious malarial fever," the disease 
 had been prevailing for at least 37 days prior to our arrival July 21 
 and that about 35 cases had been under treatment in the post hospital, 
 of which number 11 had died. As the true nature of the disease had 
 not been suspected, no precautionary measures had been taken as 
 regards the disinfection of bedding and clothing used by the patients, 
 except that in case of death the sheets and pillow slips were put in 
 bichloride solution and the mattresses and pillow exposed to sun- 
 light. An order required that the excreta of all patients under treat- 
 ment in this hospital should be carefully disinfected, and this was 
 probably carried out fairly well. The excreta for the garrison at large 
 were incinerated in permanent crematories, fires being lighted in 
 these twice a week. 
 
 Notwithstanding the omission to disinfect the bulk of the contami- 
 nated articles of bedding and clothing, the disease had not been 
 contracted by the nurses, nor by the other patients in the several 
 wards, nor by the three men who washed all of these articles. A 
 little inquiry showed that contaminated clothing was in all of the 
 eight barrack rooms without apparent detriment to the occupants. 
 Further investigation showed that a death from yellow fever had 
 occurred in this garrison as early as May 16, 1900, and that the source 
 of infection for this case, as well as for the present outbreak, was in the 
 immediately adjacent town of Pihar del Rio, to which fhe soldiers 
 had free access. 
 
 An interesting observation was the sudden attack of yellow feverT ' 
 experienced on July 12, 1900, by a general prisoner who had been) 
 confined in a cell in the guardhouse since June 6, 1900. His death) 
 occurred at the post hospital on July 18, 1900. This cell was occupied! 
 at the time by eight other prisoners, none of whom contracted the! 
 disease, although one of them continued to occupy the bunk vacated ; 
 by the sick man. As these nine prisoners had been kept under strict 
 military guard, it was impossible that the individual attacked could 
 have acquired his infection in the town of Pinar del Rio. He was, as 
 far as could be ascertained, exposed to no source of infection to which 
 his companions had not been equally exposed, and yet he alone 
 acquired the disease. It was conjectured at the time that perhaps 
 some insect capable of conveying the infection, such as the mosquito, 
 had entered through the cell window, bitten this particular prisoner, 
 and then passed out. This was, however, only a supposition. 
 
 Two instances of undoubted exposure to fomites, involving four 
 individuals, came under my observation during this inspection. In 
 
94 
 
 the one case a box of dot him:. helon n soldier who had died of 
 
 yellow fever on July 3, and which, had been packed by an enlisted 
 man on July 4, and placed in the company storeroom, was un- 
 packed for tile purpose of making an inxentory of the articles, and 
 carefully repacked on duly Is !y t \\ noniinmune soldier*, who did 
 not contract the disease 'by this exposure. In the other case the 
 very bed vacated on July is bv the commissary sergeant, who w*a 
 taken sick on July 17, and died on July ill. upied I 
 
 noniinmune soldier on the nights of the I'.Mh and LMMh of Julv. 
 Although this individual xvas badly frightened when the true character 
 of the sergeant's attack \\a> announced, the combination of fright 
 and exposure to fomites was not sufficient to produce an atta. 
 yellow fever. 
 
 The data gathered, therefore, during the inve>t iiration of this small 
 epidemic at I'inar del Kio did not tend to strengthen one's belief in 
 the theory of the propagation of yellow fever by fomih -. Tin's belief 
 had already been shaken by the manner in which the di>ea-e had 
 spread in the town of Quemados, Cuba, from which we had obtained 
 cases for bacteriologic study; for here we saw the disease pa-s fnm 
 No. in-j Real Street around the corner to No. 20 General L 
 and thence to a house immediately across this latter street, without 
 the passage of any persons between these three* houses, and to the 
 exclusion of any article of clothing, as the three families had no 
 acquaintance whatever with each other. Here the infection was 
 just as plainly carried through the air as it had been taken, through 
 this medium, to the prisoner in the cell at Pinar del Ki... \\V 
 observed in this town that the contagion passed down (leneral 
 Street with a bound to the distance of a square, passing in its journey 
 a house containing two nonimmunes, only to return a few days later 
 to this very house and seize upon both of its noniinmune inn> 
 This hardly seemed in keeping with the idea of a diffusible p<i-n 
 carried by the atmosphere. During our first week on the island, 
 we noted in a house in Quemados, where the husband and wife \\ere 
 taken down with yellow fever a few davs apart, that neither the 
 young daughter, who was removed to a place of safety on the fourth 
 day, nor an attendant who had remained in the sick room for the 
 entire 24 hours of the seventh day, had acquired the di-ea-e: but 
 that of the two remaining nurses who continued to perform their 
 duties, one was seized on the fourteenth day and the other on the 
 fifteenth day with an attack of yellow fever. This observation was 
 reenrded at the time for what it was worth. Later it was found to 
 harmonize with the observations which had been made by Surg. 
 Henry K. ( 'arter, of the Marine-Hospital Serviee. in Vs I shall 
 
 rec i ir to'these observations later in my remarks, it will suilice to here 
 state that at this stape of our investigation it seemed to me, and I 
 so expressed the opinion to my colleagues, that the time had armed 
 when the plan of our work should be radically changed; that the 
 search for the specific agent of yellow fever, while not abandoned, 
 should be given secondary ron-ideration. until we had first definitely 
 ted something about the way or wax s in \\hi< h the disease \\as 
 propagated from the sick to the, well. I felt well-nigh convinced 
 that we could obtain no light whatever upon the task that, had been 
 set before us, unless we substituted this line of work for the one we 
 had been pursuing, and that in view of the ^plendid work of Ross, 
 
YELLOW FEVER. 95 
 
 Bignami, and others with regard to the propagation of malarial fever, 
 together with the well-known thermal influences intimately con- 
 nected not only with the epidemiology of the disease in the United 
 States, but also with its endemiology on the Island of Cuba, it was 
 of the highest importance that the agency of an intermediate host, 
 such as the mosquito, should either be proven or disproven. 
 
 Remember, if you please, that here we^er^jle.ajing^witli..an epi- 
 demic disease concerning which there was no evidence whatever to 
 show that it had ever been spread by contamination of either water 
 or food; that it had always demanded a certain elevated tempera- 
 ture before it would begin its progress, which latter, both in its man- 
 ner and rate, was quite unlike that of other epidemic diseases, such 
 as smallpox or typhoid fever or Asiatic cholera; that once having; 
 begun its march, 110 hygienic measures ever instituted had been able 
 to arrest its course, except depopulation of the locality affected; 
 that while, if introduced into certain localities, it would readily propa- 
 gate itself, those sick with this disease could be carried in large num- 
 bers into other places without any danger of its spread a fact which 
 had been attested in hundreds of instances; that ships with nonim- 
 mune crews could remain at anchor with perfect safety at about 300 
 yards from an infected shore. Couple with this the natural law by 
 which it was governed, viz, its prompt control by frost, and tell me 
 what other epidemic disease could be associated in the mind with 
 this except malarial fever. 
 
 The theory that the spread of yellow fever could not b'e explained 
 by the assumption of a diffusible miasm in the atmosphere, but 
 required the presence of an intermediate host, appears to have been 
 first advanced by Bj^jIjCI'Nott, ^ Mobile, Ala., in March, 1848. 
 His views were givSTirTKIirin the New Orleans Medical Journal for 
 that year. It was also in this paper that Nott suggested the mos- 
 quito as the possible agent in the dissemination of malarial fevers. 
 He evidently did not have in mind the mosquito as the bearer of the 
 yellow-fever poison, but rather that this important office was per- 
 formed by some insect or insects that remained very close to the 
 ground. Referring to the fact to which all writers were agreed, that 
 a very imperfect barrier, such as a row of houses or of trees, would 
 often protect dwellings from the access of malarial poison, he says: 
 
 I have been able in my researches to discover no facts of this kind in connection 
 with yellow fever, and my personal observation repudiates this in toto. We never 
 find yellow fever, as the sportsman says, "up a tree," but on the contrary the materies 
 morbi, whatever it may be, creeps along the ground, regardless of winds, passing 
 under and through houses and trees, etc., and knowing no impediment but a sheet 
 of water. 
 
 Again : 
 
 It is a curious fact that from 1829 to 1837 there was no epidemic of yellow fever in 
 Mobile, and during this time the streets were beautifully shelled; since 1837 we have 
 had it five times and the shelling was not continued. If the insect theory be correct, 
 could the lime be an impediment to their progress across the street? 
 
 To Dr. Carlos J. Finlay, of Habana, must be given, however, full 
 credit for the theory of the propagation of yellow fever by means of 
 the mosquito, which he proposed in a paper read before the Royal 
 Academy in that city at its session on the 14th day of August, 1881. 
 From that date to the present time Finlay has made a number of 
 valuable contributions to the origin and mode of transmission and 
 
96 VER. 
 
 prevention of ycllo. l>urini: this time his \iews 
 
 undergone some slighl modification. Startin;: uith the idea that the 
 tic poison adhered to the mosquito's proboscis and was thus 
 mechanically transferred to the individual next bitten i \\hich specific 
 .dined by him in lss7. and even at tl ; time, to he 
 
 his micrococcus betragenUfi febris ilava". he later IV.i modified 
 his original theon. based iinon the studies of 'riieoh:dd Smith on 
 Texas lever, "so as to include the important eireun. the 
 
 faculty of tran-minini: the yellow- 'in need not he limited 
 
 to the parent insert . directly contaminated I yellow- 1 
 
 patient (or perhaps by contact with or feeding from hi- cii-cha< 
 hut may he likewise inherited hy the n ration of 1110-0,11 
 
 '(1 from the contaminated parent" <\e\\ York Medical 
 May J7. HMMi'. Of the KM) individual- experimented upon from 
 June, 1881, t" May, 1895, Finlay claimed to have produced three 
 cases of "mild alDiiminuric fever" after a period of incubation 
 
 . ini: fn>"i 5 to L'") day-: hut aa he exeivixed no eonirol OVOT tlie<e 
 indUaduals, to the exclusion of other sources of infection, no \ 
 could be attached to his results. If. indeed, one \\ere L'uided by the 
 re-ults obtained, the only logical eoin-ln-ioii to he drawn \\a- that 
 Kinlay had disproved his own theory. His failure to produce po-i- 
 tive result- wliich we now believe to be due to the fact that he did 
 not keep his insects for a sufficient length of time .inanimation 
 
 before applying them to the individual to be infected doiihile-- led 
 Finlay to promulgate the later idea that the 4 bite of the cnntamn 
 mosquito, while not producing the disease, conferred immunity upon 
 the individual bitten. He has made use of the bite of the contami- 
 nated moscjuito for this purpose in a considerable number of indi- 
 viduals. Notwithstanding tne fact that Finlay had no result- to 
 show in support of his theory, and that the latter had been wholly 
 rejected by other investigators, the argument in favor of an inter- 
 mediate host seemed so strong, as I have already stated, that I'u: 
 investigation along this line was determined upon. The mosquito 
 -elected was the one that had been used by Finlay in hi- previous 
 work, and which, with Culex pungens, is the most prevalent and 
 annoying mosquito in the city of Habana, and for that matter in all 
 the larger towns on the island. Originally designated by Fabr'n-ius 
 as Culex fasdatus* it had later been called by Hesvoid 
 mosquito. Unlike Culex jnnif/dis this mosquito bites by day u uell 
 as during the nighttime. Judging from m\ own expeii. ..uld 
 
 say that its favorite 1 lours for feeding were from -1 p. m. to in p. m. 
 
 In pur preliminary" note, above referred to, we recorded. amon-_r 1 1 
 individuals bitten py contaminated mosquitoes of thi- m 
 negative and 2 positive result-; the attack in both of the latter 
 occurring within the period of incubation of yellov the 
 
 circumstances surroumling the infection of one of these cases was 
 Midi as to exclude any other BOUTCe of infect ion. v.e announced the 
 conclusion that ''the nio-<juito served a- the intermediate host for 
 t he parasite of yellow fever. Subsequent observations have poi 
 in the most convincing manner, to the -Mimdne-s of this conch; 
 It is to these later observation- that I now de-ire to invite your 
 attention. 
 
 Interesting ami Important to otwrvc that sln.-t ho publicationof<- 
 
 . fi . i,'., : . Col ..;:"!';. Bd* p-nu:, - 
 
YELLOW FEVEK. 97 
 
 Dismiss from your minds, if you please, the idea that -yellow fever 
 is so prevalent on the island of Cuba, and that the ways of acquiring 
 the disease are so numerous, that experimental results obtained at 
 any point in the so-called endemic zone of yellow fever must be 
 thereby vitiated. Nothing to my mind could be more improbable 
 than such an opinion; for, as a matter of fact, yellow fever has been 
 confined, during the year 1900, to Habana and a few other towns, 
 coast or inland, and has not been present elsewhere on the island. 
 Hence any location selected, provided it should be 1 mile from such 
 a center of infection and surrounded by proper safeguards, would be 
 just as free from the occurrence of yellow fever as if it were located 
 10 miles from such a town. My own experience on the island of 
 Cuba had already taught me that yellow fever could be easily kept 
 out of a military garrison, although prevailing in epidemic form in a 
 town less than 1 mile distant. For this reason it was not considered 
 advisable to establish our experimental sanitary station at a greater 
 distance than 1 mile from Quemados, Cuba. Thus Camp Lazear 
 could be easily reached by the members of the board and was con- 
 veniently located as regards its base of supplies. The occurrences at 
 this camp fully justified this decision. Placed in an open field, 
 which was fairly swept at all times by the prevalent winds, and having 
 a military garrison each of whose members had been personally 
 selected by reason of former good conduct and interest in the work 
 to be here undertaken, no difficulty whatever was experienced in 
 maintaining the strictest quarantine against the outside. 
 
 Let us now present to you, as succinctly as possible, our observa- 
 tions at this camp, prefacing what I shall have to say with the 
 remark that here we proposed to attempt the infection of nonimmune 
 individuals in three ways, viz, first, by the bites of mosquitoes that 
 had previously bitten cases of yellow fever; secondly, by the injec- 
 tion of blood taken during the early stages from the general circula- 
 tion of those suffering with the disease; and, thirdly, by exposure to 
 the most intimate contact with fo mites. For this purpose, in addition 
 to the seven tents provided for the quartering of the detachment, 
 two frame buildings, each 14 by 20 feet in size, were constructed. 
 These buildings, having a cubic capacity of 2,800 feet, were exactly 
 similar, except that one of them, known as the "Infected mosquito 
 building," was divided near its middle by a permanent wire-screen 
 partition and had good ventilation; while the other, designated as 
 the "Infected clothing building," was purposely so constructed as 
 to exclude anything like efficient ventilation. These houses were 
 placed on opposite sides of a small valley, about 80 yards apart, and 
 each 75 yards distant from the camp proper. Both houses were 
 provided with wire-screen windows and double wire-screen doors, so 
 that mosquitoes could be kept without or within the buildings, as 
 the experimenter might desire. 
 
 At first the results obtained at this station were not encouraging. 
 From November 20, 1900, the date of the establishment of the sta- 
 tion, until December 4 a period of 2 weeks we had tried to infect 
 4 individuals, with entirely negative results. Two of these had been 
 bitten twice, at intervals of 3 days, by contaminated mosquitoes 
 which had been kept from 10 to 14 days after they had fed on yellow- 
 fever cases ; while the other 2 nonimmunes had been thrice bitten, at 
 79965 S. Doc. 822, 61-3 : 7 
 
98 YELLOW PEVEK. 
 
 the same intervals, by mosquitoes that had bitten cases *>f yellow 
 
 : ID !.> 1 s da\ s before. As the weather (luriiiLT this time \\ M 
 and the inserts had been kept at room temperature (and this is prac- 
 Hy outdoor temperature in Cuba), we conjectured that the nega- 
 tive re-idt- illicit. perhaps, be thus explained. \Ye remembered that 
 Daniels 1 in repeating, durini: the winter season, Ross's oh-ervations 
 \\ ith proteosonia infection of birds, had obtained a much smaller per- 
 centage of successes than had Ross, who \\<>rked during summer 
 i her. We would have been glad to draw some encouragement 
 from our negative experiments, also, \\ith infected bedding. lut. M 
 at this date (Dec. 4) our 3 subjects had been sleeping uith fomite- 
 only 4 nights (which is within the period of incubation of the di- 
 ttos comfort was debarred. 
 
 On the fifteenth day of our encampment therefore (Dec. 
 p. in.) W( ntrated our insects, so to -speak, on one of these non- 
 
 immunes Kissinger by name selecting 5 of our m^t promi-ini: 
 mosquitoes for the purpose. These haa been contaminated as f.-l 
 follows: Two, 15 days; 1, 19 days; and 2, 21 days pn-viou-ly. This 
 inoculation was more successful, for, at the expiration of .'-5 day 
 9J hours the subject, who had been under strict (quarantine during 
 1 5 days, was suddenly sei/ed with a chill about midnight . I >e< emberS, 
 which was the beginning of a well-marked attack of yellow fever. 
 
 I can not let this opportunity pass without c i xpre--in^ my admi- 
 ration of the conduct of this young Ohio soldier, who volunteered for 
 this experiment, as he expressed it, " solely in the interest of humanity 
 and the cause of science," and with the only proviso that he should 
 receive no pecuniary reward. In my opinion this exhibition of 
 moral courage has never been surpassed in the annals of the Army of 
 the United States. 
 
 The following morning (Sunday, Dec. 9, at 10.30 a. m.) 
 selected from those insects that had bitten Case I, one mosquito that 
 seemed to us to possess the best record of contamination, as it had 
 bitten a fatal case of yellow fever, on the second day of the di 
 19 days before. This insect was applied to a Spanish immigrant, 
 who had been strictly quarantined at our station for 19 days. At t he 
 expiration of 3 days and 11 hours (Dec. 9, 9.30 p. m.) this individual 
 was also seized with an attack of yellow fever. 
 
 In the meanwhile, on December 8, 1900, at 4 o'clock p. m., we had 
 
 applied to a young Spaniard three of the mosquitoes that had, three 
 
 (lays previously, bitten Case I, together with an additional mosquito 
 
 contaminated 17 days before. At the end of 4 days and L'O hours 
 
 (Dec. 13, noon) this "Spaniard suddenly lost his vivacity and took to 
 
 his bed. The following morning at !> a. in. his febrile paroxysm 
 
 began. His case, which was the mildest of our series, was also ma iked 
 
 long period of incubation, vix. :> days and 17 hours. He had 
 
 i in quarantine 9 days. 
 
 Decemoer 11, at 4.30 p. m., the identical -1 insects which had bitten 
 Caselll were fed on a Spanish immigrant who had been in quarantine 
 the past 21 days. At the expiration of 3 days and 1!4 houi> 
 (Dec. 15, noon) he was likewise seized with yellow fever. 
 
 Thus within the period of one \\cek December '.' to IT, uc had 
 succeeded in producing an attack of yellow fever in i-m-h of the l 
 
 > On trmiumiMion of Proteofom* to Bird* by the Mosquito- Royal Society, Reports of Malarial c-.n,- 
 mlttM. London, WOO. 
 
YELLOW FEVER. 99 
 
 individuals whom we had caused contaminated insects to bite, and 
 in all save 1 of the 5 nonimmunes whom we had originally selected 
 for experimentation. 
 
 It can readily be imagined that the concurrence of 4 cases of yellow 
 fever hi our small command of 12 nonimmunes within the space of 
 1 week, while giving rise to feelings of exultation in the hearts of the 
 experimenters, in view of the vast importance attaching to these re- 
 sults, might inspire quite other sentiments in the bosoms of those 
 who had previously consented to submit themselves to the mos- 
 quito's bite. In fact, several of our good-natured Spanish friends 
 who had jokingly compared our mosquitoes to "the little flies that 
 buzzed harmlessly about their tables/' suddenly appeared to lose all 
 interest in the progress of science, and, forgetting for the moment 
 even their own personal aggrandizement, incontinently severed their 
 connection with Camp Lazear. Personally, while lamenting to some 
 extent their departure, I could not but feel that in placing them- 
 selves beyond our control they were exercising the soundest judgment. 
 In striking contrast to the want of confidence shown by these Anda- 
 lusians who had agreed to be bitten by mosquitoes was the conduct 
 now displayed by the three young Americans, who had consented to 
 jeopardize their lives by exposure to fomites and who, as a matter of 
 fact, had already spent 15 nights in a small, illy ventilated building, 
 breathing in an atmosphere dreadfully contaminated by the soiled 
 garments of yellow-fever patients. With the occurrence of these 
 cases of mosquito infection, the countenances of these men, which had 
 before borne the serious aspect of those who were bravely facing an 
 unseen foe, suddenly took on the glad expression of "schoolbovs let 
 out for a holiday," and from this time their contempt for "fomites" 
 could not find sufficient expression. Thus illustrating once more, 
 gentlemen, the old adage that familiarity, even with fomites, may 
 breed contempt. 
 
 As the continued good health of those who were occupying the 
 " infected clothing building" pointed strongly to the harmlessness 
 of fomites, the next experiment at this station was undertaken for the 
 purpose of demonstrating that the essential factor in the infection of 
 a building with yellow fever is the presence therein of mosquitoes that 
 have bitten cases of yellow fever. 
 
 Accordingly at 11.55 a. m., December 21, 1900, 15 mosquitoes were 
 freed in the larger room of the " infected mosquito building," which, 
 as I have said, was divided into two compartments by a wire-screen 
 partition. The interval that had elapsed since the contamination 
 of these insects was as follows: One, 24 days; three, 12 days; four, 
 8 days; and seven, 5 days. The only articles of furniture in this 
 building consisted of three beds, one being placed in the mosquito 
 room and two beyond the wire screen, these latter intended to be 
 occupied by two " control" nonirnmunes. The articles of bedding 
 as well as the bedsteads had been carefully disinfected with steam. 
 At noon on the same day, 5 minutes after the mosquitoes had been 
 placed therein, a plucky Ohio boy, Moran by name, clad onlv in his 
 nightshirt, and fresh from a bath, entered the room containing the 
 mosquitoes, where he lay down for a period of 30 minutes. On trie 
 opposite of the screen were the two controls" and one other non- 
 immune. Within 2 minutes from Moran's entrance he was being 
 bitten about the face and hands by the insects that had promptly 
 
100 YELLOW PEVML 
 
 settled down upon him. Seven in all hit him at this visit. At 4.30 
 
 :.. the same day, he again rut. .1 remained '20 minute*. 
 
 during which time 5othen hit him. The following day at -I.:i0 p. in.. 
 he again entered and remained 1 ."> minutes, durffiff which time :> 
 insects bit him. making the nnmher 1 ."> that had fed at the-e three 
 visits. The building \\as tlien d- cpt that the two non- 
 
 imnn MtroU" continued to OOCUpJ the heds on tlie noninfeeted 
 
 Mde of the screen. On Christmas morning, at 11 a. m.. this brave 
 lad \\as Mricken \\ith yellow fever, and bad B -harp attack, which 
 he hore without a murmur. Tlie period of incubation in this 
 case was 3 days and '2:\ hour*, counting from liis 1ir-t \i-ii. or - 
 days and 17J* hours if reckoned from his la-t viMt. The t\\o 
 
 itrols'' who liiid slept each night in this house, only protected 
 hy tlie wire l>ut breathing the common atraospnere of the 
 
 building, had remained in good health. They continued to BO remain, 
 although required to sleep here for 1M additional nighN. A^ M 
 liad remained in strict quarantine for tlie period of ::_' days prior to 
 
 ittack. the source of his infection must he found \\ithin this 
 house. 
 
 In the order of succession, the next experiment undertaken at this 
 camp was the injection of blood, taken from Case V (Moran . heneath 
 the -kin of a Spaniard, hut I will defer further mention of this li: 
 experimentation until I have completed the mos<piit< bete 
 
 are by far the most important. I, therefore, invit iitention 
 
 to Case VI, Martinez by name. His case is of inteiv-t as hearini: 
 upon the number of days which must elapse after the contamination 
 of the mosquito before it can convey the disease to a second indi- 
 vidual. 
 
 An additional point of some importance, I think, is that win 
 prior to the time of Moran' s infection (Case V) the contamin. 
 mosquitoes had been taken to the men in their tents and there applied. 
 from this date December 17 the subjects were invited to vi 
 particular room attached to our "Mosquito building." hut quite 
 ^epaiate from it, where the contaminated insects wei i um- 
 
 mer temperature, and were there given the opportunity of e\po>in_u; 
 themselves to an attack of yellow fever by putting their hand- in-ide 
 of certain mosquito-inhabited jars. I may as well t"ll you now that 
 of seven persons who availed themselves of this privilege five 
 acquired yellow fever. 
 
 After a quarantine period, therefore, of 9 days. Marline/ \i>ited 
 this room on December 17. I'.IOO. and was bitten hy ll mo^|iiitoes 
 which 4 days before had fed upon Case I of this series. The result 
 
 Was quite negative. December 24, or on the eleventh <lay after 
 
 out animation, the subject- was again bitten by 7 of these insects 
 all that remained of the original 14. Again no infection took place. 
 Aft ei- r, full days, or on December :>(). at 11 a. m.. Marline/ v 
 bitten by the surviving 1 of these mosquitoes, i. e.. on the st 
 teenth day after their contaminat ion. On the fourth day thereafter, 
 .lanuary I, 1901, at 10.30 a. m., he was sei/ed \\ith yellow f. 
 which ran a tynical cour-e. The period of incubation wa 
 22i hours. Although we can not say on what particular day tln^e 
 insects became capable of conveying the disease, we are able to st ate 
 that they were incapable of Infecting on the fourth or eleventh day 
 
YELLOW FEVER. 101 
 
 after contamination. This experiment agrees with others that we 
 have made during this investigation and in which we have failed to 
 convey the disease by the bites of insects at intervals varying from 
 2 to 9 days after contamination. These observations seem to indi- 
 cate that after the parasite has been taken into the mosquito's stom- 
 ach a certain number of days must elapse before the insect is capable 
 of reconveying it to a second individual. This period probably rep- 
 resents the time required for the parasite to undergo its cycle of devel- 
 opment and reach the mosquito's salivary glands, and, as far as our 
 experience goes, would appear to be about 12 days in summer weather 
 and most probably about 18 or more days during the cooler winter 
 months. Case VI, therefore, does not support the opinion of Finlay 
 that the bite of the contaminated mosquito confers immunity against 
 a subsequent attack of the disease, since we have seen that neither 
 the bites of 14 insects on the fourth day nor the bites of 7 on the elev- 
 enth day after contamination prevented in the least the conveyance 
 of the infection by the bites of 4 only of these mosquitoes on the seven- 
 teenth day. 
 
 I will now ask you to look at Case IX, as this case serves to illus- 
 trate some points of interest. In the first place, this subject, an 
 American, was bitten by insects that had fed upon Case I of our series 
 on the third day of his illness ; that is, during the secondary fever which 
 followed a complete intermission in this case. Secondly, these mos- 
 quitoes had been kept alive on sugar and water for a period of 39 days 
 before being applied to Case IX. Of the original 5 insects that had 
 bitten Case I on the third day, 4 were still alive on the thirty-ninth da} r 
 thereafter and 3 showed every evidence of good appetite. Thirdly, 
 this particular subject having passed 21 nights in the "Infected cloth- 
 ing building," during which time he was exposed to the most intimate 
 contact with fomites, without apparent detriment to his health, had 
 been kept in strict quarantine for yet 30 days longer at Camp Lazear. 
 At the expiration of this time, or on January 19, 1901, at 4.30 p. m., he 
 visited our mosquito room, where he was bitten by these 39-day-old 
 insects, 3 in number. This inoculation was followed by an attack of 
 yellow fever of moderate severity, which began at 4 p. m., January 
 23, the period of incubation being 3 days 23J hours. 
 
 Case XII you will find of equal interest, as this individual was in- 
 fected, in the same room, by the bites of two of these same mosquitoes 
 on the fifty-first day after their contamination, the period of incuba- 
 tion being^ 3 days 2^ hours and the character of the attack mild, 
 while Case XIII will conclusively demonstrate that these identical 
 insects, on the fifty-seventh day after their contamination, were not 
 only capable of conveying the infection, but of producing an attack of 
 such severity that the subject's life hung in the balance for several 
 days. I regret to have to state that the individual who had con- 
 sented to be bitten by these insects on the sixty-fifth day after their 
 contamination failed to fulfill his promise at the last moment; so 
 that otherwise I can not say to what old age these mosquitoes might 
 have attained. Deprived of further opportunity to feed on human 
 blood, one died on the sixty-ninth day and the other on the seventy- 
 first day after their original contamination. The duration of life in 
 the case of these mosquitoes will readily explain how the poison of 
 yellow fever can remain even in a depopulated area for a period of 
 
102 YELLOW FEVER. 
 
 2i months; so that, as is well known, those who enter the infected 
 area, even at the expiration <>f this period, are liable to acquire the 
 disease. 
 
 \IY i^ tliat of our tenth and last successful moMjuito inl'cc- 
 tiin at Camn La/ear. This individual after j:> davs' (juarantine, 
 having been bitten on 1-Ybruarv 7. 1901, at 1* |>. n:.. l>y t \\ o moxjui- 
 toes on the sixteenth day after their contamination. \\as- seized \\ith 
 an attack of \dlo\\ ferer at noon, February in, after an incubation 
 stage of 2 days 22 hours. 
 
 Thus you will observe that at this station, under strict <niarantine 
 precautions, we succeeded in conveying the disease to in nonimmuncs 
 DV means of the bites of mosquitoes tnat ha<l previously fed 
 of yellov. .1 interval varying from Hi to 57 days befoic being 
 
 applied to the person to be infected: that the attack of yellow fever 
 always followed the bite of the mosquito within the period of inculm- 
 tion of this disease, and that during the period which elapsed from 
 December .">. I'.ioO, the date of our first inoculation, till February 7, 
 1901, the date of our last inoculation '.."> days), the order of occur- 
 rence of these cases corresponds with the order of inoculation, except 
 that Case II, having a longer incubation period than Case III. the 
 order of their relative occurrence became reversed. 
 
 Table I serves to illustrate this point. 
 
 By an examination of this table it will be seen that of i:$ individuals 
 whom we attempted to infect by bites of contaminated moxp: 
 we succeeded in 10, or 76.92 per cent. Of the three negative cases, it 
 will be observed that one (Case VI), who had reacted nc^ativch t<> 
 the subcutaneous injection of 1.5 c. c. of blood on Dec-em her 26, 1900, 
 also reacted negatively to the bites of mosquitoes on January 8, 1 !'<) 1 . 
 and this notwithstanding the fact that he was bitten by tl lame 
 
 insects which nine days oefore had infected Case VII. We have L 
 ground for the opinion, therefore, that this Spaniard may be lo 
 upon as one who possessed a natural immunity to yellow fever, ( 
 cially as he was tne only one of five persons who did not develop the 
 disease after receiving an injection of blood taken from the general 
 circulation, and was also the only one of five nonimmuncs who did 
 not contract yellow fever when bitten by insects \\hich already had 
 been proven capable of conveying the disease to other im livid 
 
 \ "III. while negative to mosquito inoculation on December Js 
 and _ )( .. ]'.()(), reacted positively to a blood injection on Janu- 
 
 ary 8, 1901. This particular individual, Jernigan. entered our 
 "infected mosquito building'' on December _'s ;im l LMJ, p.Min. one 
 week after Moran's visit, and \\as bitten on each occasion by one 
 mosquito. As 66 per cent of the mosquitoes freed in the buildin 
 December 21, 1900, had already been destroyed m<>t pn.hahl 
 the small red ants that were present in considerable numbers the 
 subject may have been bitten by in-ects that were not more than i;; 
 days old, in which ca-e he \\oiild hardly have become infected. While 
 considering the advisability of adding other contaminated inse< 
 those in the house for the purpose of infecting .IernL r an. oppi -tunit \ 
 presented for making a blood injection, and, as he was the only avail- 
 able subject in the camp at the time, it was determined to mak> 
 of him for this purp. 
 
 c XIII. our third negative eaefl <>f mosquito inoculation, was 
 bitten by 12 mosquitoes that had fed on Case Vll within s hours of 
 
YELLOW FEVER. 103 
 
 the commencement of his attack. Although these insects were 22 
 days old when applied to Case XIII, on January 25, 1901, no result 
 followed the bites. As the subcutaneous injection of 2 c. c. of blood 
 taken from the general circulation of Case VII, at the end of 24 hours, 
 produced an attack of yellow fever in Case VIII within the period of 
 incubation, it would appear to indicate that the mosquito at certain 
 periods of the disease may fail to obtain the parasite owing to its 
 absence, at that particular time, from the capillary circulation. This 
 is not unlike what we sometimes find as the result of an examination 
 of the blood of malarial fever, especially in the sestivo-autumnal type 
 of the disease. Table I also shows that, in addition to the positive 
 case (VIII) to which I have already invited your attention, we 
 obtained three other positive results by the subcutaneous injection 
 of blood taken from the general circulation on the first and second 
 days of the disease, viz, Cases VIII, XI, XII. The quantity of blood 
 injected in these three cases was 1.5 c. c., 0.5 c. c., and 1 c. c., respec- 
 tively. The production of yellow fever in this way is of much scientific 
 interest first, as serving to confirm what the mosquito inoculations 
 had already shown, viz, that the parasite is present in the general cir- 
 culation; second, that passage through the body of the mosquito, 
 although this would seem to be nature's method, is not absolutely 
 essential in the life history of this microorganism ; and third, that the 
 period of incubation of the disease, when thus produced, corresponds 
 fairly closely to that occasioned by the mosquito's bite. A point of 
 considerable importance brought out by the blood injection was the 
 absence from this blood, on careful bacteriologic culture, of any bac- 
 terium which grows on our ordinary media by aerobic methods, thus 
 excluding absolutely the bacillus icteroides of Sanarelli from further 
 claim as the specific agent of yellow fever. 
 
104 
 
 YKLU>\V FKVKK. 
 
 iff 
 
 iiiii i 
 
 - rf 
 
 lllll i iiiii ill 
 
 "- 
 
 ft. : 
 
 fcfi : :fc : 
 
 :??Sg 
 
 i! 
 
 :S :So s 
 
 ft 
 
 Hi 
 "'" '=" a a *8 y'ssi a^ s -' -' 
 
 g::a:g 
 
 g B ***-&> 
 
 > *' 
 
YELLOW FEVER. 105 
 
 You will recall that we undertook at Camj> Lazear still a third 
 method of propagating this disease, viz, by fomites. I must now tell 
 you that during the whole time that we were producing cases of 
 yellow fever by the bite of the mosquito and by blood injection, we 
 were leaving no stone unturned in order to produce the disease by 
 contact with fomites. Sleeping every night in the "Infected cloth- 
 ing building/' to which no sunlight ever came, and in which the 
 circulation of air was purposely made as defective as possible; en- 
 gaged in the morning in packing boxes with garments much soiled 
 by contact with the bodies and excreta of yellow-fever patients, and 
 at night unpacking these same boxes in order to obtain articles for 
 their beds and clothing for their bodies in other words, sleeping in 
 the very beds and garments just vacated by cases of yellow fever, 
 seven nonimmune young Americans, averaging each 21 nights amid 
 such uninviting surroundings, came out of this pesthouse, so to speak, 
 at the expiration of their term none the worse for their experience. 
 Not one had contracted the disease. 
 
 In the light of these results we can hardly be expected hereafter to 
 lend much credence to such observations as that given by Harvey 
 Brown, in 1872, 1 as narrated by Dr. A. A. Baldwin, of Jacksonville, 
 Fla., presumbly from memory, some 13 years after the event. In 
 this instance two children in Jacksonville, Fla., "contracted the 
 disease by being present at the opening of a trunk belonging to their 
 uncle who, a few days before leaving Habana, had visited the yellow- 
 fever hospital, where he passed by the beds of those who were throw- 
 ing up black vomit; and this, notwithstanding the fact that his coat, 
 the only woolen clothing he had on at the time, had been sponged 
 with alcohol after his return from the hospital! " 
 
 Or this, recorded by Rochester, 2 as an example "of the wonderful 
 tenacity with which fomites hold the pestiferous material" and after- 
 wards "convey it to mankind with intense effect." "In September, 
 1856, an infected ship from Cuba was detained at the quarantine 
 anchorage off Staten Island, N. Y. Several passengers died, and 
 some were ill on board. The garments and bedding were thrown 
 overboard. Bay Ridge, a delightful suburban neighborhood of 
 Brooklyn, lies directly across the bay, distant about 1 mile from the 
 anchorage mentioned. The wind and tide deposited a number of 
 garments that had been thrown away on the beach which terminated 
 the lawn of Col. Charles Prince, an old and respected resident. In 
 taking his usual morning walk he discovered the clothing and ex- 
 amined it with his cane, not otherwise handling it. He had no sus- 
 picion that it came from quarantine and never saw it again. In four 
 days he was taken illl and died in a week of yellow fever." We lose 
 our faith in this brine-soaked bedding when we find, according to 
 Elisha Harris's report, 3 that on the Long Island shore, directly oppo- 
 site the quarantine grounds (Bay Ridge) 6 cases of yellow fever and 3 
 deaths from black vomit had already occurred between the 13th and 
 21st of July, 1856, and that "from the latter date the malady ex- 
 tended fearfully until it had visited nearly every dwelling on the 
 shore of that beautiful Bay Ridge, 30 cases and 15 deaths having 
 occurred in that district previous to August 1." 
 
 1 Report on Quarantine, 1872, pp. 34 and 35. 
 
 2 Transactions Am. Med. Association, vol. 30, 1899, pp. 128, 129. 
 * Annual Report of the Physicians of Marine Hospital, 1857. 
 
106 YELLOW FEVER. 
 
 I could quote many other instances contained in the literature, but 
 as not one of them, as far as my search has gone, will hear the slur': 
 intelligent critici-m. I \\ill not* further trespass on your time ex cept to 
 say that, in my opinion, every epidemic of yellow fever that has otc uned 
 in the United States, both prior to and since tlie period when disinfec- 
 tants were used, has pointed in the plainest manner to the innoceii 
 fomites as a means of propagation of this disease; for with the on 
 cold weather and under those conditions of lessened ventilation <fd\u 11- 
 ings and artificial heat that should have aided in the spread of the 
 epidemic, just the contrary ell'ect has always resulted, t'nder the cir- 
 cumstances one must eitner conclude that an external temperature 
 of 32 F. is quite sufficient to bring about, and that speedily, the 
 thorough disinfection of the many tons of infected clothing and bed- 
 ding contained in the houses of a large city at the end of an epidemic 
 of yellow fever or that fomites have no part in the incp.-i- at im of the 
 disease. The latter conclusion, it seems to me, is the only intelligible 
 one, in view of our present knowledge of the disinfectant action of 
 oold on bacteria. 
 
 Let us now see if there are any facts observed by others in connec- 
 tion with the ordinary propagation of yellow fever \vhich Mipport 
 those recorded by us as the result of mosquito bites at Camp La/ear. 
 Since in our limited experience, affecting 'J:* individual-, we have not 
 observed the production of the disease by the bite of the nioxjnito 
 within less than 12 days after contamination, we would expect that, 
 when a case of yellow fever was imported into a town or house where 
 the conditions were favorable for its propagation, a secondary case 
 would not occur within a less period of time than about 14 or more 
 days. I may say that various observers have noted that alter the 
 occurrence of the first case in a town, a considerable interval clap-e> 
 (2 or 3 weeks) prior to the appearance of other cases. Although such 
 general statements are of value, what we need are exact observa- 
 tions recorded under such conditions that the secondary cases can be 
 positively referred to a certain limited source of infection. This, of 
 course, can best be done where the disease has been imported into 
 small settlements or into isolated houses, and it was under just such 
 favorable circumstances that Carter, of the Marine Hospital Service, 
 made his observations at Orwood and Taylor, Miss., in 1898, "on the 
 interval between the infecting and secondary cases of yellow lc , 
 Here, in a community of more than average intelligence, con-i-tini: 
 "not of a town, or even a hamlet, but only of a neighborhood," as 
 Carter puts it, it was possible to record with accuracy the date of 
 introduction of the infecting cases and the date of occurrence of 
 secondary cases. 
 
 Table II gives the results of this investigation. 
 
 This table shows that of 16 houses in which the interval between 
 the infecting case and the first secondary case was recorded, l. r >. or 
 93.7 per cent, correspond with the, mosquito interval; that is, the 
 secondary cases occur at just tho interval 13 to 23 days when we 
 would expect them to develop, provided the mosquito was concerned 
 in tho propagation of the disease. It will he observed that in only 1 
 of the 16 first secondary cases was the interval as short as 11 days 
 and 15 hours. If the commencement of tho attack in this case has 
 been recorded correctly, it would indicate that the number of days 
 
YELLOW FEVER. 
 
 107 
 
 which we have given as "about 12" for the development of the para- 
 site within the mosquito would have to be shortened somewhat 
 probably to 10 days. In our first successful experimental case, where 
 the disease was produced by the bite of the mosquito on the twelfth 
 day after the insect's contamination, we could not say, of course, that 
 this particular mosquito would not have conveyed the infection had 
 it been allowed to bite on the tenth or eleventh day after contamina- 
 tion. 
 
 On the other hand, if we take all the secondary cases that occurred 
 in these 16 houses, we will find that of a total of 71 cases, only 1 
 developed the disease after so short an interval as 11 days and 15 
 hours; in other words, 70, or 98.5 per cent, of the secondary cases 
 occurred after an interval of 13 days. As a matter of fact only 2 of 
 these secondary cases occurred within a less period than 14 days, 1 
 developing on the twelfth and the other on the thirteenth day. 
 
 TABLE II. Interval between infecting and secondary cases of yellow fever. 
 
 
 House. 
 
 Year. 
 
 Date of 
 infecting 
 cases. 
 
 Date of 
 first sec- 
 ondary 
 case. 
 
 Inter- 
 val in 
 days. 
 
 Next sec- 
 ondary 
 case. 
 
 Number 
 of second- 
 ary cases. 
 
 Orwood. Miss 
 
 1 
 
 1898 
 
 Aug 6 
 
 Aug 23 
 
 164 
 
 Aug 24 
 
 6 
 
 Do 
 
 2 
 
 1898 
 
 Aug. 29 
 
 Sept. 13 
 
 15 
 
 Sept. 13 
 
 6 
 
 Do 
 
 3 
 
 1898 
 
 do 
 
 Sept. 18 
 
 20 
 
 Sept 18 
 
 4 
 
 Do... 
 
 5 
 
 1898 
 
 Aug. 31 
 
 Sept. 29 
 
 29 
 
 Oct. 2 
 
 3 
 
 Do 
 
 6 
 
 1898 
 
 do 
 
 Sept 20 
 
 204 
 
 Sept. 20 
 
 5 
 
 Do... 
 
 7 
 
 1898 
 
 Sept. 3 
 
 Sept. 26 
 
 23 
 
 Sept. 30 
 
 6 
 
 Do 
 
 8 
 
 1898 
 
 Sept. 17 
 
 Oct. 8 
 
 21 
 
 Oct 8 
 
 2 
 
 Do.. 
 
 9 
 
 1898 
 
 Aug. 31 
 
 Sept. 22 
 
 214 
 
 Sept. 22 
 
 4 
 
 Do 
 
 10 
 
 1898 
 
 Sept. 4 
 
 Sept. 20 
 
 16 
 
 do 
 
 2 
 
 Do.. 
 
 11 
 
 1898 
 
 Sept. 25 
 
 Oct. 8 
 
 13 
 
 
 1 
 
 Do 
 
 15 
 
 1898 
 
 Sept. 2 
 
 Sept. 22 
 
 204 
 
 
 1 
 
 Do.. 
 
 16 
 
 1898 
 
 Aug. 29 
 
 Sept. 9 
 
 U1J 
 
 
 
 Taylor, Miss 
 
 1 
 
 1898 
 
 Aug. 7 
 
 Aug. 27 
 
 20 
 
 Sept. 3 
 
 13 
 
 Do... 
 
 2 
 
 1898 
 
 Aug. 17 
 
 Sept. 2 
 
 16 
 
 Sept. 6 
 
 8 
 
 Do 
 
 3 
 
 1898 
 
 Aug. 10 
 
 Aug. 25 
 
 15 
 
 Aug 28 
 
 2 
 
 Edwards, Miss ... ... 
 
 
 1897 
 
 Aug. 8 
 
 Aug. 22 
 
 14 
 
 Aug. 26 
 
 10 
 
 
 
 
 
 
 
 
 
 1 11 days 15 hours. 
 
 I do not know what conclusion you may draw from the data con- 
 tained in Table II, but to my mind they are strongly suggestive that 
 the same mode of propagation which we were making use of at Camp 
 Lazear during the past winter was at work in the epidemic of yellow 
 fever at Orwood and Taylor, Miss., during the summer of 1898. 
 
 From my own personal experience, I can only add one observation 
 to those given by Carter, viz, at Quemados, Cuba, where of two 
 nurses who remained continuously in attendance upon a case of yellow 
 fever, one contracted the disease on the fourteenth day and the other 
 on the fifteenth day after the commencement of the primary case. 
 
 While the temptation is great to extract from the literature other 
 observations confirmatory of those given (and they are numerous), I 
 must refrain from doing this, since I promised to confine myself largely 
 to my own experience in regard to the propagation of yellow fever. 
 For this reason and because I feel that I have already trespassed 
 on your patience longer than I had any right to do, I must omit any 
 reference to the habits of culex fasciatus, or of the thermal influences 
 concerned in the propagation of this mosquito, both of which are of 
 much importance in connection with the subject under consideration. 
 
108 YELLOW FKVEB. 
 
 I trust that I have said enou:h. however, to indicate to you that, in 
 my opinion, tho ideas Which we have heretofore hold oonoornim: tho 
 
 Propagation of yellow fever must unden/o oonndorahlo rocastinir. 
 do not believe 'that we can longer a-cribo \\ilh confidence any part 
 of the spread of this disease to fomitcs. for under such conditions of 
 intimato and lon^-continucd exposure as could never occur in the 
 natural course of oven -day life \\e have looked in vain for its 
 development. 
 
 While in matters pertaining to tho public hoalth. cleanline^ .should 
 always stand next to L'odliness. 1 do not think that we will bo justified 
 in assigning so much importance hereafter to those insanitary condi- 
 tion- which, bring due especially to pollution with animal 
 mail -d. in some mysterious way. to aid in the spl 
 of this disease. Strange as it may sound, I do not believe that the 
 enforcement of the most rigid hygienic regulations, such as ue have 
 heretofore known them, will nrevont i he propagation of thi- -rave 
 epidemic disease, provided it sliould again bo imported into this coun- 
 try. I seriously doubt if we can longer class yellow fever with the 
 "filth disoa- The apparent result- obtained by tho imp- 
 sanitary arrangomonts instituted by Gen. Butler in the city of New 
 Orleans, during the year 1862, and carried on by his military 
 cessore, probably served to strengthen, as much as anything else, the 
 view held by tne profession that filth was, if not o-sential. yet of 
 extreme importance, in aiding the spread of yellow fever. I dare 
 say that but few stopped to consider that Gen. Butler found the city 
 of New Orleans already quite free of yellow fever, and that the same 
 system of blockade which kept this disease out of the former city, 
 under, improved sanitary conditions, kept it out of other Southern 
 seaports during the same period, although their sanitary conditions 
 remained unchanged. If one is inclined to believe that impi 
 hygienic conditions, as usually understood, will arrest the spread of 
 yellow fever, let him turn to the city of Habana under American sani- 
 tary administration. Probably in no city in the world have such 
 unremitting sanitary efforts been put fortn as in the city of Habana 
 since our occupation in January, 1899. We were told tliat the hard 
 work of Gen. Ludlow and his assistants was responsible for the marked 
 < locrease of cases of yellow fever during the first seven months of 1899 
 and appearances seem to indicate as much nevertheless, with the 
 commencement of Spanish immigration, during August of that \ 
 and the introduction of susceptible material, cases of yellow i< 
 began to rapidly multiply, so that the city had a late summer and fall 
 epidemic of this disease. Concerning the occurrence of yellow I 
 in that city during the past year, Mai. Harvard, chief surgeon, Depart- 
 ment of Cuba, in a recent report, after describing the thorough work 
 which had been done by the sanitary authorities and its marked effect 
 upon the reduction in deaths, especially from tuberculosis, goes on to 
 say: 
 
 It is certain that in Habana, in 1900, no visible correlation could be seen between < 1 i r> 
 and yellow fever; the district which became first strongly infected lies east and south 
 of the Parque Central, and is one of the cleanest and best constructed, while the most 
 insanitary wards became infected late in the season and only to a slight extent; i h<- 
 malodorous district reserved to houses of ill-fame hardly had a case. Yellow fev< 
 
 I lowed the poor and unclean, nor the mark of previous inf. li-.n, but null, r tin- 
 movement of nonimmunes: wherever these located, there the infection searched and 
 found them, regardless of the hygienic conditions of their premises. 
 
YELLOW FEVER. 109 
 
 What is the sanitary story, then, for the year 1900? Simply that 
 with the return of summer weather and the continued influx of new 
 material, and in spite of unremitting efforts to keep the city clean, 
 Habana has experienced a more serious epidemic of yellow fever, 
 affecting its civilian population, than it has had during the preceding 
 20 years. Need we now express surprise at such a result ? Have we 
 not seen at Camp Lazear, under the very best hygienic surroundings, 
 six individuals attacked with yellow fever, after a few short visits to a 
 new building whose foundation stood on the unbroken turf and whose 
 rooms were filled with sunshine and with an atmosphere just swept 
 in from the ocean, at the very moment of infection? Where then, 
 gentlemen, shall we look for the agent that is vitally concerned in the 
 propagation of yellow fever ? In the light of these newer observations 
 which I have had the pleasure of presenting to you, I believe that we 
 may affirm, with some degree of confidence, that here, substituting 
 culex for anopheles, we have to deal with the same source of infection 
 to which we now trace the malarial fevers the mosquito. 
 
CHAPTER 5. 
 
 EXPERIMENTAL YELLOW FEVER.' 
 
 IU WALTER RF.KM. M ! . Surgeon, United Stairs \rn\\ .l\v L, M !>.. 
 
 and A. AGRAMOSTE. M. D., Contract Surgeon^ I nit<d stairs Army. 
 
 Subsequent in the prrM-niniinn of our paper to the Pan-American 
 Congress : in llabana, we succeeded in producing some additional 
 Cases of vcl low fever at our experimental sanitary Matimi near ( v )u<>- 
 
 inados, Cuba. We have thought that brief reports of these CMJ 
 
 be followed by remarks on experimental yellow fever fmm t he clinical 
 point of view, would ho of interest to the members of this associat inn, 
 and especially to those* who reside in sections of the country where 
 each year yellow fever is liable to apnear in epidemic form. 
 
 Perhaps it miirht be well to recall the fact that the cases of yellow 
 fever here to be recorded were produced like those heretofore reported 
 by us, under strict quarantine re:ulations and at a -peeiai experi- 
 mental sanitary -tat inn, near the town of Quemadns. Cuba. 
 
 In a series of 12 experimental cases produced at this camp during 
 the period from Decembers, 1900, to February 7. P.Mil an int. 
 of 65 days it should be borne in mind that the order <>f occurrence 
 exactly correspond with the order of inoculation, except that Case II. 
 inoculated at 4 p. m., December 8, 1900 having a longer period f 
 incubation than Case III, inoculated at 10.30 a. in Decemh 
 1900 the order of their; relative occurrence became re\ i 
 Moreover the attack always followed within the period of incubation 
 of the disease, and concerned only those nonimmune individuals who 
 had consented to submit themselves for experimentation. Of a total 
 of 16 individuals who thus consented, 14 contracted yellow f. 
 whereas of 5 nonimmunes, who did not consent and were therel<.n 
 not subjected to experimentation, none acquired the d .-dthou.irli 
 
 otherwise placed under exactly similar surrounding In it> occur- 
 rence, therefore, at this station, yellow fever strictly obeyed the 
 behests of the experimenters, both as to place and time of occurrence. 
 Recovery took place in all cases. 
 
 (A) CASES PRODUCED BY (Hi l\JH ROM "K BLOOD. 
 
 Case I. \V. J., American, nonimmune, aged 27 in quarantine since December 
 20, 1900 with his full consent, at 11 a. m., January 4, 1901, was injc< t.,1 >U!M -ut:t- 
 neously with 2c. c. of blood taken from the general circulation "fa case of mild \'ll.\v 
 fever at the beginning of the second day of the disease and having a tcin; 
 100.8 F. The subject, who had born in Mriei nu:inmiin<- ;it tin- .-tati<>n fur tin- ; 
 of 45 days, remained in his usual health until the early morning of January 8, 
 he complained of slight frontal headaches. At 6 a. m. his temperature was 98. 
 and pulse 70; 9 a. m., temperature 99.8 F., pulse 95; frontal headache increased, with 
 
 t RMd before the Sixteenth Annual Meeting of the Association of American Physicians, held at Wash- 
 tattoo, April 30, May 1 and 2, 1901. 
 
 i The Etiology of Yellow Fever. An Additional Note. Read at the Pan-American Con*re, Habana, 
 February 4-7, 1001 
 
 Thcac 
 
 were reported In our Additional Note. 
 110 
 
YELLOW FEVEK. 
 
 Ill 
 
112 YELLOW PE\ 
 
 plight chilly sensations in the foot and lo\\ . Ities, Tl me con- 
 
 gestion of the eyes and his usual florid compl'xi-n \\as heightened in color, At 
 a. m., temperature 100.6 F., pulse 97. Complains of some pain in the lumbar 
 region. At 1 1 JO a. in., temperature 101.4 F., pulse 99. The height of the febrile 
 paroxysm was reached at 3 p. m. the same day, when the temperature wa.- 
 and pulse 108. The facial expression was now characteristic of yellow lever, The 
 eyes were deeply inj<-< tod and watery and the face much suffused. Photophobia 
 moderate- headache and backache severe. The skin wa The 
 
 remission occurred at tht ; hours 9 a. m. January ! ho temperature 
 
 had fallen to 99.4 F. and the pulse to 86. The subsequent history WM that of * CM| 
 of yellow fever of moderate H Mtnimin was found in tin- urino at the - n<l 
 
 of the sixty-first hour. There was some bleeding from the gums on the third day 
 and moderate ocular jaun<li> on the fourth day. Fever disappeared on the morning 
 of the seventh day. (Chart I.) 
 
 Cote II. W. O., American, nonimmune, aged 28, in quarantine since December 
 20, 1900. On January 8, 1901, at 9 p. m., with his full consent, he was given by 
 cutaneous injection 1.5 c. c. of blood taken from the mediancrphalic vein of Case I, 
 just 12 hours after the beginning of the attack and when the temperature was 102 : 
 that is, just after the first febrile paroxysm began to d< he subject 
 
 in his usual condition during the following two days. 
 
 January 11, 1901, at 6 a. m. his temperature was 98.9 F. and pulse 70. 1 1- 
 plained of being disturbed by dreams during the night and had some frontal head 
 At 9 a. m. temperature 100 F., pulse 77. At 10. 15 a. m. temperature 101.4 F., pulse 
 76. Eves decidedly congested and face moderately suffused. At 12 ' -U -k 
 when the temperature had risen to 103.2 F. and the pulse to 10i'. the h.-L-ht ..f the 
 primarv paroxysm had been reached. Headache and backache were now much 
 complained of. The facial expression was characteristic. The r -mi-ion <>< -curred 
 at the end of 24 hours, lasted one day, and was followed by a very moderate secondary 
 fever. A distinct trace of albumin was found in the urine passed at 2 a. in. .la unary 
 12, 17 hours after the attack began. A few hyaline casts were also presei 
 bleeding from the gums occurred on the second and third days of sickness, 
 character of the attack in this case was vey mild. The albumin, which at no time 
 amounted to more than a distinct trace, did not disappear, however, until January 
 24. (Chart II.) 
 
 Case III. W. F., American, nonimmune, aged 23, was, with his full consent 
 p. m. o'clock January 22, 1901, injected subcutaneously wit of blood i 
 
 on the second day from the general circulation of a severe case of yellow fever, which 
 was fatal on the seventh day of the disease. The patient's ten \\hi-n the 
 
 blood was withdrawn, was 103 F. and pulse 90. Tne subject remained well during 
 the following day. January 24, at 6 a. m., his temperature was 98.4 F., and pulse 
 78. He partook of a hearty breakfast at 6.30 a. m., wnich he vomited soon afterwards. 
 At 7 a. m. he complained of dizziness and general lassitude. Temperature, 98.4, 
 pulse 78. At 9 a. m., chilliness complained of, but there is no record of toi'iperature 
 or pulse. At 9.30 a. m., temperature 100.6 F., pulse 82. Frontal headache 
 marked. Eyes already injected and face slightly suffused. At 10.30 a. m 
 ture 101.2 F. and pulse 86. An hour later his temperature was 102.6 F. and \ 
 82. The height of the primary paroxysm was reached at 1 p. m win -n the ter 
 ture was 102.8 F. and pulse 98/ At this hour photophobia was well marked mid 
 constant complaint made of severe frontal headache and backache, together with 
 pains in the lower extremities. The skin was moist. The mm it tin- 
 
 end of 36 hours. The subsequent course was that of a case of yell '.rate 
 
 severity. With the return of the secondary fe\ -r there \v > sharp backache 
 
 and headache. Albumin appeared in the urine at the end of 57$ hours. Ocular 
 jaundice was present on the tnird day and thereafter unt il convalescence. The ^mm 
 did not bleed, although they were swollen and injected .l-id-d mi th. 
 
 day, and albumin disappeared on the eighth day. (Chart 1 1 1 > 
 
 Case IV. J. H. A., American, nouimmuno, aged 22, with hi-< full OH 
 
 January 26 and 27, except that on the afternoon ..f the laM-memmned date h. 
 plained of occipital headache. This was present on the following morning, January 
 28; otherwise he felt well. His temperature at noon was 98.6 F., and pulse 68. 
 Occipital headache continued. He partook of dinner with fair appetite. He was not 
 seen again until 3 p. m. In the meanwhile, at 1.15 p. m., the subject states that 
 while sitting alone in his tent, he began to feel cold, and that this was quickly fol- 
 lowed by a decided chill with increase of headache. He noted the hour in writing at 
 
YELLOW FEVER. 
 
 118 
 
 79965 S. Doc. 822, 61-3 8 
 
114 YELLOW FEVBB. 
 
 the time. At 3 p. m. his temperature was 103.6 and pulse 120. The eyes were 
 intensely congested and the face deeply suffused. The patient was very restless , and 
 complained bitterly of occipital headache and backache. Photophobia waf 
 marked. He vomited several times within the next 2 hours. Skin hot and dry. 
 The height of the primary paroxysm was reached at 3.30 p. m., at which h.-ur tin- 
 temperature was 104.2 P., and pulse 120. The subsequent history was on 
 yellow fever. There was no remission in the fey. r until the fourth day. \\hcn the 
 temperature fell to 101.2 F. Now, for the first time, the patient ceased to complain 
 of occipital headache and backache. Albumin appeared at the end of 18} hours 
 (7.30 a. m., January 29). A few hyaline casts were also present at this time. I h 
 specii ne passed at 6.40 a. m., January 30, contained albumin onc-t \\vnt icth 
 
 by volume, and many fine and coarse, granular, bile-tinted casts. Ocular jaundice 
 appeared on the third day. The skin ot the face and of the anterior part of t li- 
 ana thorax was tinted on the fourth day. This rapidly became intensified a : 
 The secondary fever lasted about 30 hours. th> tcnijicraturc falling to 97.2 F. at rj 
 o'clock (midnight) .f the tilth day. Marked fluctuations of temperature o.niinued 
 until the eleventh day of illness. Recovery was slow and much delayed l>y the 
 pment of a carbuncle in the left sacral region. A trace of albumin was still 
 present on March 1, 32 days after the attack had begun. (Chart IV.) 
 
 The production of yellow fever by the injection of blood tak< -n 
 from the general circulation is of much interest as showii 
 that the parasite is present in the blood, at least during the early 
 stages of the disease, and secondly, that its passage through an i 
 mediate host, although this would seem to be nature's met 1m. I, is not 
 essential in the life cycle of this parasite. Thus yellow fever is 
 analogous to the malarial fevers, in that it may be produced either 
 by the bite of a certain species of mosquito, or by the injection of 
 blood taken directly from the general circulation. 
 
 Another point to which we nave elsewhere referred, but which is 
 considered of sufficient importance to bear repetition lien-, is that in 
 each of the foregoing cases of experimental yellow fever pro* lured by 
 the injection of blood, careful cultures made from the same blood 
 drawn from the vein immediately after injection or, as in one instance, 
 made from the same syringeful of blood that conveyed the disease, 
 failed to show the presence of Sanarelli's bacillus. In one case colo- 
 nies of Staphylococcus pyogenes citreus were obtained, while in the 
 remaining three cases no growth whatever occurred. The exclusion 
 of Bacillus icteroides from further consideration as the specific a ji 1 1 1 of 
 yellow fever would, therefore, seem to have been conchiMvely <; 
 mined by these experiments. 
 
 (B) CASES PRODUCED BY THE BITE OF THE MOSQUITO, CULEX FA8CIATU8. 
 
 Case V. L. F., American, nonimmune, aged 28 in quarai .or 20, 
 
 1900 was, with his full consent, at 3. 30 p.m. , January l!i, l!in, hi tu-n by three mos- 
 quitoes that had been contaminated 39 aays previously, by feeding on the blood of a 
 well-marked case of yellow fever, on the third day of the disease. The subject 
 remained in his usual condition of health until the afternoon of January on of 
 
 this date his temperature was 97.8. Soon after this hour he took to his bed, com- 
 plaining of frontal headache and general lassitude. At 3 p. m. his temperature was 
 99.2 and pulse 78. At 4. 10 p. m. the temperature was 100 F. and pulse 104. A 
 sense of chilliness, especially of the lower extremities, and increased frontal headache, 
 were now complained of. Eyes already injected and face flushed. At 5 p. m. th- 
 temperature was 101.2 F. and pulse 104. The height of the paroxysm was \ 
 8.20 p. m., at which hour the temperature was 103.6 F. and the pulse IK). The eyes 
 were deeply congested and photophobia very marked. Headache and back 
 so intense as to cause the patient to complain bitterly. He vomited once at 9 p. m. 
 January 24, 3 a. m., the temperature had (alien to 100.2 and the pulse to 104, hut \\ ii h 
 only slight amelioration to the patient's discomforts. At noon the thermometer 
 marked 102. Remission occurredat the end of 33 hours, with marked diminution of all 
 disagreeable symptoms. The secondary fever, attended by increased headache and 
 
YELLOW FEVER. 
 
 115 
 
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 8 
 
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 b 
 
 
 
 84 
 
 $ 
 
 #4. 
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 86 
 84 
 
 68 
 ~38 
 
 66 
 
 C-C. 
 
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 77 
 
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 F 
 
 ^ 
 
116 YELLOW FEVER. 
 
 backache, lasted four days, the temperature dropping to normal at 6 p. m. of the 
 seventh day. The case was one of moderate severity. Albumin a; p-ared in the 
 urine at the end of the forty-second hour. 'Ocular jaundice was quite noticcai 
 the afternoon of the second day. Some jaundice of the face and an ten r - -i-n f the 
 chest was seen on the fourth day. Many bile-tinted granular casts were present in the 
 urine on the third day. and thereafter until the eleventh day. The albumin which 
 reached one-fifteenth by volume on the sixth day disappeared on the twelfth day. 
 (Chart V.; 
 
 Cote VI. C. W., American, nonimmune, aged -7. with his full consent, was at 
 9.30 a. m., January 31, bitten by 2 of the 3 mosquitoes that had been applied t<> the 
 foregoing Case V. The interval that had elapsed since their contamii 
 therefore, 51 davs. The subject remained well until in o'clock noon. I-Vhru. 
 when he complained of heaviness in his legs and some supraorbital pain 
 
 ire at this hour was 99 F. and pulse 70. At 1.30 p. m. it had ri- n to UK) F., 
 and at 5 p. m. to 100. F. and pulse to84. The primary risepf fever, which was 
 what fluctuating in character, did not reach its height until at the < n ) .1 j; 
 noon, February 1, when the temperature was 102.4 and the pulse 92. 
 was now suggestive of yellow fever. Remission occurred at the end of J~> hours and 
 lasted for about 1 day. The secondary rise was slight in char.it -t. -r, the temperature 
 falling to normal on the morning of the sixth day. The case was very mild in < har 
 acter. Albumin appeared at the end of 75 hours (beginning of fourth day 
 amounted to more than a distinct trace and disappeared on the eighth da; 
 was no ocular jaundice, and although the gums were injected and swollen, there was 
 no hemorrhage at any time. The patient perspired freely throughout the at 
 Convalescence was rapid. The subject had been in quarantine for the period of 6 
 days prior to inoculation. (Chart Y I 
 
 Case VII. J. H., American, nonimmune, aged 26, with his full consent, was bitten 
 at 11 a. m., February 6, 1901, by the same 2 mosquitoes that had 6 <i 
 bitten Caso VI. Fifty-seven days had therefore elapsed since the insects had 
 contaminated by biting a case of yellow fever. He remained well until IL' 
 noon, February 9, when he experienced slight chilly sensations, accompanied by 
 yawning. At this hour his temperature was 99 F. and pulse 72. At :> p. m . t. ni 
 perature 98.8, pulse 72. Says mat he feels "out of sorts, but has no \ i 
 
 5. 30 p. m. his temperature was 100.6 F., pulse 78. He was not seen until 7 .:><) p. m , 
 when he complained of backache and severe general headache, mon- intense through 
 the frontal region. Eyes much injected, photophobia very marked, fa< e \\\; 
 He was stretching and yawning constantly, complained of nausea, and vom: 
 small quantity of partially digested food. The height of the primary fever was reached 
 at 3 p. m., February 10, i. e., 22 hours after the commencement of the attack, when 
 the temperature was 102.8 and the pulse 98. Remission of th- and 
 
 pulse to 74 occurred at 6 a. m., February 11, making the duration of the primary 
 paroxysm 36 hours. Twenty-four hours after the remission had occurred the 
 perature had risen to 102.4 with a pulse of 70. The fever continued to steadily 
 increase until midnight of February 12, when a temperature of 105 F. was 
 with a pulse of 90. The subsequent course was that of a case of 
 Slight oozing of blood from the gums occurred as early as the third da 
 jaundice, beginning on the third day, became later very distinct and was associated 
 with general jaundice. Albumin, however, did not appear until the sixth day. The 
 fever subsided on the ninth day, and was followed by a slow convalescence. The 
 subject had been in strict quarantine for a period of 78 days prior t.> in<>< -illation. 
 (Chart VII.) 
 
 Case VIII. C. S., American, nonimmune, aj/ f h his full con 
 
 bitten at 2 p. m., February 7, 1901, by 3 mosquitoes that had been mtamr 
 16 days previously by biting a fatal case of yellow fever on the second day of the 
 disease. The subject remained well until the early afternoon of the third day. 
 ruary 10. He ate his dinner at noon with good app i it < At I p. m. f hiatempentan 
 was 100 F., pulse, 90. Frontal headache was now complained of. Tl 
 rapidly more marked, and pains in the limbs were also present. Three hours later. 
 4 p. m., the fever had risen only one-lift h of a d.-.-n-c, but at <i p. in. it had re;. 
 103 F. and pulse, 96. At this hour he had severe headache and backache, with 
 general pains over the body. The facial expression was now characteristic. Eyes 
 brightly injected, photophobia well marked, and face decidedly congested. At 9 
 p. m. temperature was 103.2 and pulse 1 12. The skin was moist. Remission occurred 
 at 6 a. m., February 12, 41 hours after the commencement of the febrile paroxysm. 
 The secondary fever, which was moderate in character, lasted 4 days, the i. \< r sub- 
 siding on the seventh day. Ocular jaundice was slight. A few hyaline casts 
 present on the third and subsequent days, but no albumin was found until 1 p. m., 
 
YELLOW FEVER, 
 
 117 
 
118 x > ii. LOW FF.vn:. 
 
 1-Vt.ruary 18, that is, 36 hours aiu-r th> tVvrr luul sul>Mu-a. It was present at a <lis- 
 tiurt trace in all specimens examined until 3 p. m., February 23. i '>: was 
 
 rapid. The subject had been in quarantine for a period of 25 days prior to inocula- 
 tion. (Chart VIII.) 
 
 The foregoing cases of experimental yellow fe\ \ . V 1 . and 
 
 VI 1 are. we think, of especial importunes asshowing thelenirt h of time 
 during \vhirh the mosquito may remain capableof convex -in.ir the infec- 
 tion. In previous papers \ve have reported (i cases of yeil..\\ fever pro- 
 duced by tlie bitonf m. (|iiitos at intervals varying from 1 - t _ 1 days 
 after the contamination of the insects. In the ca>es here reported 
 tiie periods intervening between the contamination of the insect and 
 the production of the disease were much longer. '. 51, and :>7 
 
 day-, respectively. As one of the-e injects lived until the sixty-ninth 
 and another until the seventy-first day after contamination. we have 
 for the iiist time an explanation of the fact, several times noted in 
 the literature, that the omtagion of yellow fever may cling foi 
 months to a building that has been vacated by its occupants, or to 
 the infected area of a town, even though this latter h;:s been entirely 
 depopulated. These particular insects also \\eiv contaminated at a 
 hit erst age of the disease than in any of our other cases, i. e..on the third 
 day and during the secondary rise of the fever, following a complete 
 intermission in the temperature. We have, therefore, been able to 
 demonstrate that the parasite is present in the general circulation 
 both after and before the stage of remission. How much later in the 
 disease the parasite may stifl be found a matter of much int. 
 and importance the observations thus far made do not determine. 
 Although the 3 mosquitoes applied on the third day, as above stated. 
 acquired the parasites and were able to affect 3 individuals with yellow 
 fever, a single mosquito applied to the same case of yellow fever on 
 the fourth day of the disease failed to obtain the parasite, as sho\\n 
 by the negative result following its bite 40 days after contamination. 
 That not all mosquitoes become infected, however, with the parasite 
 by bitingyellow fever patients is shown by several observat i >ns made 
 by us. We submit only one. 
 
 Case IX. J. W., American, nonimmune, was, with his full r<ms-nt. mi January 
 25, 1901, bitten by 12 mosquitoes (C.fasciatus) that had fed on a ill \vlln\\- 
 
 fever in a man named Martinez on January 3, 1901, within 8 hours of the com- 
 mencement of the attack. Although these mosquitoes had been kept at a summer 
 temperature for 22 days, the result of the experiment was entirely nc-aiivr. Thai 
 the parasites were present in Martinez's blood at the end of 24 hours was fully nhown 
 by tne effect produced by injecting 2 c. c. of his blood drawn at this time beneath the 
 skin of Case I of this report. 
 
 Observations such as the foregoing would indicate that the mos- 
 quito at certain periods of the disease may fail to obtain the parasite, 
 owing to its absence at that particular time from the capillary circu- 
 lation. Concerning the matter of the propagation <>f yellow t 
 by other species of culex than C. fasriatus, we have only 1 negative 
 observation to record of an individual bitten by 5 C. pungens that 
 had been contaminated by biting a case of yellow fever in days pre- 
 viously. To a single negative experiment such as this no importance 
 can be given, so that this question must be left for future obfl 
 tions to determine. 
 
 Touching the subject of the possible transmission of the parasite 
 to the daughter insect by means of infection of the ovum, we have 
 also but a single observation to record. In this case the bites of 14 
 
YELLOW FEVER. 
 
 119 
 
120 .A'W WM\ 
 
 mosquitoes, hatched from the ova of a mosquito (C.fascialu^ that had 
 already shown itself capable of conveying the disease, were followed 
 by an entirely negative result. 
 
 'Including the cases heretofore reported by us, we have thus far 
 siu veeded in conveying yellow fever to 12 individuals by means <>f 
 the bites of contaminated mosquitoes, and to 4 other persons by sub- 
 cutaneous injection of blood taken from cases of this disease a 
 total of 16 cases. While ordinarily so small a number of cases would 
 l>e sufficient to enable one to arrive at definite conrlu-i-'Hx con- 
 cerning the general character and course of an acute infection- 
 disease, the conditions under which the majority of these en 
 
 observed were such as to jrive us valuable data miK-eni'mi: twn 
 matters of very great practical importance in connection with this 
 disease, viz, the period of its incubation and the difference in d< 
 in the character of it- attacks. Further, as these caa 
 under constant observation, even from the time of inoculation, \N- 
 are not only able to report upon the earlie-t j>n -monitory svmntnm-. 
 but also to give the'pnmary temperature curve; and, in addition, t<> 
 note the time of appearance of Albumin in the urine, all of whie! 
 of interest in the clinical history of yellow fever. 
 
 Period of incubation. The accurate determination of the period 
 of incubation of any one of the acute infectious diseases is always a 
 matter of scientific interest. If the disease is one which, like yellow 
 fever, is of exotic origin and whose importation is liable to give 
 to a widespread epidemic, then the determination of its incubati\<- 
 stages becomes of the highest practical importance. This import ;> 
 as a Question of public hygiene, is increased, if as recent observations 
 , would seem to indicate, the importation of this disease is brought 
 about only by the sick individual and not bv his baggage or clothing. 
 While the older authors were willing to prolong the period of incuba- 
 tion of yellow fever to 2 or 3 weeks or even longer, the tendency of 
 physicians at the present time is to shorten this stage to about 5 days. 
 Reference to a few of the later text-books on the Practice of Medicine 
 will sufficiently indicate this. Davidson, in Allbutt's System, 1 puts 
 down the period of incubation as "ranging between 24 hours and \ 
 or 5 days. Stevens 2 says that it may vary from " a few hours to a 
 week." Osier 8 says that "the period of incubation is usually 3 or 4 
 days, but it may be less than 24 hours or prolonged to 7 days." 
 According to Tyson, 4 "yellow fever has a period of incubation of 
 from 24 hours to 5 days, very rarely exceeding the latter." Stern- 
 berg 5 says that this period "does not usually exceed 4 or 5 days and 
 may be less than 24 hours." Carter,' in a recent valuable paper, 
 gives the results of his studies on the period of incubation of yellow 
 fever, based on observations extending over a considerable number 
 of years. Under Class III of his observations, which are the most 
 valuable, he includes "those persons who, living in a clean environ- 
 ment, go into an infected one, stay only a short time, and t lien ret urn 
 to a clean environment where they remain until the fever develops." 
 
 A System of Medicine, London, 1807, Vol. II. p. 394. 
 
 Practice of Medicine. Philadelphia, 1808,p. 286. 
 
 The Practice of Medicine, New York, 1800, p. 185. 
 Practice of Medicine, Philadelphia, 1000. p.TJ5. 
 
 Buck'* Reference Handbook o? the Medical Sciences, 1880, Vol. Ill, p. 58. 
 
 The Period of Incubation of Yellow Fever, New York Medical Record, March 0, 1001. 
 
YELLOW FEVER. 
 
 121 
 
 1 
 
 70 
 
 I 
 
122 
 
 
YELLOW FEVER. 
 
 123 
 
 Of 12 cases thus accurately observed by himself the incubative stage 
 was as follows: 
 
 Cases. 
 
 Days' 
 incuba- 
 
 
 tion. 
 
 2 
 
 3 
 
 6 
 
 3+ 
 
 2 
 
 4 
 
 1 
 
 $ 
 
 12 
 
 
 The following table gives the result of our observations in 16 cases 
 of experimental yellow fever. 
 
 TABLE I. Period of incubation of experimental yellow fever. 
 
 No. of 
 
 case. 
 
 Date of inoculation. 
 
 Method of inocu- 
 lation. 
 
 Date of commencement of 
 attack. 
 
 Incubation 
 
 1 
 
 \ug. 27 1900 2 p. m 
 
 Mosquito 
 
 Aug. 31 1900, 9 a. m 
 
 Dys. hrs. 
 3 7 
 
 2 
 
 Aug. 31, 1900, 11 a. m 
 
 . .do 
 
 Sept. 6, 1900, 1 p. m 
 
 6 2 
 
 3 
 4 
 
 Dec. 5, 1900, 2 p. m 
 Dec. 8, 1900, 4p.m.. 
 
 do 
 
 . .do ... 
 
 Dec. 8, 1900, 11.30 p. m 
 Dec. 14, 1900, 9 a. m 
 
 3 9} 
 
 5 17 
 
 5 
 
 Dec. 9, 1900, 10.30 a. m 
 
 do 
 
 Dec. 12, 1900, 9.30 p. m 
 
 3 Hi 
 
 6 
 
 Dec. 11, 1900, 4.30 p. m... 
 
 . .do.... 
 
 Dec. 15, 1900, 12 noon 
 
 3 19i 
 
 7 
 
 Dec. 21, 1900, 12 noon 
 
 do 
 
 Dec. 25, 1900, 11 a. m 
 
 3 23 
 
 8 
 
 Dec. 30, 1900, 11 a. m . 
 
 .. .do 
 
 Jan. 3, 1901, 10.30 a. m 
 
 3 22i 
 
 9 
 
 Jan. 4, 1901, 11 a. m 
 
 Blood injection 
 
 Jan. 8, 1901, 9 a. m 
 
 3 22 
 
 10 
 
 Jan 8 1901 9pm 
 
 do 
 
 Jan 11 1901 9 a. m 
 
 2 12 
 
 11 
 
 Jan. 19, 1901, 3.30 p. m 
 
 Mosquito 
 
 Jan. 23, 1901, 3 p. m 
 
 3 23i 
 
 12 
 
 Jan. 22, 1901, 1 p. m . . 
 
 Blood injection. .. 
 
 Jan. 24, 1901, 9 a. m 
 
 1 19" 
 
 13 
 
 Jan. 25, 1901, 12.15 p. m 
 
 do 
 
 Jan. 28, 1901, 1.15 p. m ... 
 
 3 1 
 
 14 
 
 Jan. 31, 1901, 9.30 a. m 
 
 Mosquito 
 
 Feb. 3, 1901, 12 noon 
 
 3 2i 
 
 15 
 
 Feb. 6, 1901, 11 a. m 
 
 do 
 
 Feb. 9, 1901, 5 p. m 
 
 3 6 
 
 16 
 
 Feb. 7, 1901, 2 p. m 
 
 do 
 
 Feb. 10, 1901, 12 noon 
 
 2 22 
 
 
 
 
 
 
 The average period of incubation of the 16 cases embraced in 
 Table I will be round to be 87 \ hours, or 3 days 15 J hours. If we 
 separate the 12 mosquito infections from the 4 cases produced by the 
 injection of blood, we have for the former a period of incubation of 
 94 hours or 3 days and 22 hours, and for the latter an incubative 
 stage of 67^ hours, or 2 days 19J hours. The average period of incu- 
 bation, therefore, in the cases brought about by subcutaneous injec- 
 tion of blood was shorter by 26^ hours than those occasioned by the 
 mosquito's bite. By the former method, this stage varied from 43 
 hours to 94 hours, while in the mosquito infections the shortest incu- 
 bative period was 70 and the longest 146 hours. If we accept those 
 cases produced by the mosquito's bite as the usual method of propa- 
 gation of this disease, it will be observed that of the 12 cases 1 occurred 
 on the third day, 9 on the fourth day, 1 on the sixth day, and 1 at 
 the beginning of the seventh day after incubation. 
 
 While our results, therefore, confirm the statement of later writers 
 that the period of incubation of yellow fever does not usually exceed 
 4 or 5 days, they also seem to indicate very plainly that this stage 
 may be prolonged more frequently, perhaps, than had been supposed. 
 
 In 16.6 per cent of our cases the period of incubation exceeded the 
 usual quarantine period of 5 days. If we add Carter's cases to those 
 observed by us, we find that of 24 cases the period of incubation 
 
124 
 
 YKLLUW KKVKK. 
 
 I i 
 
 I 
 
YELLOW FEVER. 125 
 
 exceeded 5 days in 3, or 12.5 per cent. We will not further dwell 
 on this subject than to remark that cases No. 2 and No. 4 of our series 
 could have passed quarantine on the morning of the sixth day 
 after inoculation, with a clinical thermometer under the tongue, with- 
 out exciting any suspicion by reason of the presence of fever. 
 
 Character of the attack. We desire to call attention particularly to 
 the difference in the degree of severity of the attack as shown by our 
 experimental cases. Like all of the other acute infectious diseases, 
 we have reason to expect that yellow fever will affect different indi- 
 viduals according to their individual susceptibilities, and hence that 
 we will encounter mild as well as severe cases. The results which 
 we have obtained confirm this expectation. Based upon the char- 
 acter of the attack, the 12 cases due to mosquito inoculation may be 
 divided as follows: 
 
 Severe i 2 
 
 Moderately severe 6 
 
 Mild 3 
 
 Very mild 1 
 
 12 
 
 The 4 cases produced by the injection of blood gave the following 
 result : 
 
 Severe 1 
 
 Moderately severe 2 
 
 Mild.. 1 
 
 Thus the cases which were mild or very mild in character consti- 
 tuted 33 per cent of those infected by the mosquito's bite and 25 of 
 those produced by blood injection. It is to the diagnosis of the former 
 cases that we desire to direct special attention. To one familiar with 
 yellow fever, or even to one unfamiliar with its clinical features, the 
 diagnosis of our severe and moderately severe cases should have pre- 
 sented no difficulty. The sharp headache and backache, the charac- 
 teristic facies, the ocular jaundice, together with the presence of albu- 
 min in the urine, except in 1 case to be hereafter referred to, with the 
 negative result of a blood examination, would have been a sufficient 
 complex of symptoms to have rendered the diagnosis tolerably certain. 
 Even in our 3 "mild" cases, were the physician on his guard and 
 acquainted with the temperature curve and pulse from the very onset 
 of the attack and, besides, careful in the testing of each specimen of 
 urine passed, a diagnosis of yellow fever could have been made with 
 reasonable probability. We believe, however, that, in the ordinary 
 course of events, where there was no reason to suspect the presence 
 of yellow fever the average practitioner would have probably failed 
 to appreciate the true nature of these attacks. Such was the admis- 
 sion which we ourselves were compelled to make, although in con- 
 stant attendance and thoroughly acquainted with these cases from 
 their very beginning. The short duration of the primary fever in one 
 instance; the rapid amelioration of the earlier symptoms in all; the 
 absence of albumen during the first 3 days, or its presence, as a mere 
 trace, in certain specimens, followed by its absence in succeeding 
 specimens; the slight icteroid hue of the conjunctiva to be obtained 
 only in a certain light and then doubtfully all served to render a 
 
126 YELLOW FEVER. 
 
 khre diagnosis exceedingly dilheult. Several physicians, who saw 
 these milder cases at our request, readily acknowledged the improba- 
 bility of a coirect diagnosis berni: made in tlie absence of the complete 
 data which we were able to furnish concerning them. In the one . 
 which we have classed as "very mild" yellow fever we believe that 
 the matter of a correct diagnosis would have been in the highest de- 
 gree improbable. The attack consisted of a single paroxys 
 hours' (fcmtion. during which the temperature only reached II 
 period of 6 hours. It is true that albumin was found in the urine at 
 the end of :>7 hours, but the quantity was exceedingly small and only 
 to be detected by the most delicate testing. It was only present in I 
 or 2 specimens passed on the third day. A slight trace was piv-mt in 
 a specimen passed at 9 a. m. of the fourth day and in that passe. 1 at 
 4.40 p. m. of the fifth day. Intervening specimens of urine, several in 
 number, contained no albumin. A weft-marked papular eruption 
 which appeared on the fourth day of the disease, and which was -on- 
 fined to the trunk and arms, would hardly have rendered the diag- 
 nosis easier. We suppose that during the prevalance of an epi<! 
 of yellow fever a physician who was thoroughly acquainted \\ ith the 
 several types of this disease would probably class tnis case as one of 
 extremely mild yellow fever, with a wide margin for doubt. Under 
 all other circumstances we feel confident that cases of this character 
 would escape diagnosis. That cases of mild yellow fever may and do 
 serve as foci for the development of other cases our own observations 
 demonstrate, since we have been able to propagate the disease from one 
 such mild case by means of the bites of contaminated im>s<juitoi>. -ind 
 from another case of like character by the subcutaneous injection of 
 2 c. c. of blood. 
 
 THE ONSET AND PREMONITORY SYMPTOMS. 
 
 Of the 12 cases produced by mosquito inoculation, the onset was 
 sudden in 2 and gradual in 10. In both of the former the attack 
 occurred during the night, the patient, also, in both instance-, IM-HILT 
 awakened by the occurrence of a decided chill. In 1 of the 2 cas. 
 sudden onset, the subject complained of slight supraorbital headache 
 during the afternoon preceding the attack. Of 4 cases produced by 
 the injection of blood, the onset was sudden in 1 the only case 
 marked by a chill and gradual in 3. The attack in all of i 
 blood cases began during the daytime. As writers generally state 
 that in yellow fever the chances of infection are greater during the 
 night, we have thought that, perhaps, the time of inoculation of our 
 experimental cases (which was during the day except in 1 ii 
 might have had some influence upon their occurrence, as a rule, 
 during the daytime. If the hour of inoculation in all of our cases 
 should have taken place at about sunset, then, with the same period 
 of incubation, 7, or 43 per cent would have experienced their attacks 
 at night. 
 
 Of the 13 cases in which the onset was gradual by mosquito 
 inoculation, 10; by blood injection, 3 frontal headache, the pain 
 being referred to the supraorbital region and extending into the 
 temporal region, was the most frequent premonitory symptom. It 
 was present in 10 and absent in 3 cases. This symptom preceded 
 the attack in these cases at intervals varying from 2 to 48 hours. 
 
YELLOW FEVER. 127 
 
 In 2 cases no premonitory headache was complained of, while in 1 
 case occipital headache preceded the onset by 24 hours, and con- 
 tinued to be of this character throughout the attack. Dizziness was 
 complained of by 3 of the gradually developing mosquito cases, and 
 a sense of weight in the lower extremities by the 2 others belonging 
 to this group. All of the cases of gradual onset (13 in number) com- 
 plained of lassitude and want of appetite, on which account all took 
 to their beds prior to the onset or fever. Ten of these individuals 
 complained of slight sensations of chilliness generally confined to 
 the lower extremities at the beginning of the attack, while in 3 
 this symptom was entirely absent. In our experimental cases, 
 therefore, frontal headache and muscular debility were the most 
 frequent and prominent premonitory symptoms. After the attack 
 had developed, the symptoms correspond to those described at 
 length by various writers and with which all are familiar, except that 
 black vomit did not occur in any of our cases. 
 
 THE FEVER. 
 
 As we have had prepared charts of our several cases of experi- 
 mental yellow fever, from which all the data concerning temperature 
 and pulse can be obtained, it will not be necessary for us to make 
 extended remarks under this heading. Medication being practically 
 nil in our cases, both temperature-curve and pulse can be accepted as 
 faithfully representing wnat normally takes place in an attack of 
 this disease. When ice water enemas or cold sponge baths were 
 used by the attending physician, this is noted on the chart. It 
 should also be remembered that pur patients were put to bed at the 
 very first manifestation of the disease, and carefully transported to 
 the yellow-fever wards on the very same beds which they had occu- 
 pied in camp. This probably had some effect upon the subsequent 
 course of the fever. The record of temperature being taken every 3 
 hours from the time of inoculation enables us to give the complete 
 curves of both the primary and secondary febrile paroxysm. Our 
 charts therefore differ considerably from those given by the various 
 writers on yellow fever in that they round out, as it were, the primary 
 stage more fully. An examination of these charts will show that 
 although the primary rise of temperature is tolerably abrupt and 
 reaches its height within a comparatively short time, it does not 
 reach its maximum so quickly as the description of writers would 
 seem to indicate. The trihpurly record in 10 of our mosquito inocu- 
 lations shows that this period of primary rise varies from 12 to 24 
 hours. In 3 cases it was 12 hours; in 2, 15 hours; in 1, 15J hours; 
 in 1, 20J hours; in 1, 22 J hours; and in 2, 24 hours. The average 
 period of the 10 cases was therefore a fraction over 16 hours. 
 
 In striking contrast to these was the short period of the primary 
 rise of temperature in the 4 cases produced by blood injection. In 
 these it varied from 2\ to 9 hours, the remaining 2 cases giving 6 and 
 7 hours respectively, the average for the 4 cases being only 6 hours. 
 In all of the 12 cases due to mosquito inoculation, the primary rise of 
 temperature was followed by a distinct remission or intermission, 
 which was generally reached within 48 hours. The same remission 
 was present in 3 of the 4 cases produced by blood injection. We are 
 
128 
 
 YELLOW FEVER. 
 
 able to give the duration of the primary paroxysm accurately in the 
 10 cases produced at Camp Lazear by the bites of mosquitos, viz.: 
 
 The average duration of these 10 cases was 43 hours. In i 
 cases caused by the injection of blood tin* length of the primary 
 paroxysm was 24 hours in 2 cases and 36 hours in 1 case tin- 
 being 28 hours. We may therefore say that not only the average 
 period of incubation, but also the primary rise of temperature, as 
 well as the length of the first febrile stair*' were all shorter in the 
 cases produced by blood injection than in those due to the mos- 
 miito's bite. Of the 12 cases due to the latter mode of inoenlation 
 tne first febrile stage was followed by an intermission in 'J, and a 
 remission in 10 cases. Of those produced by the injection of blood, 
 3 showed a distinct remission and 1 no intervening fall of temp 
 ture. The duration of this intermission varied from 3 to 27 hours. 
 This was. followed by a second febrile stage or paroxysm in 1 1 of the 
 12 mosquito inoculations, and in 3 of the 4 cases due to the injection 
 of blooa. The duration of this second febrile paroxysm was from 2 
 to 5 days. 
 
 Experimental yellow fever then, as we saw it at Camp Lazear, 
 consisted of a primary and secondary febrile paroxysm, with an 
 intervening remission or intermission more frequently the former. 
 The secondary was much longer than the primary febrile stage. 
 
 In 1 of our mosquito inoculations a relapse occurred on the ninth 
 day of the disease, and was characterized also by - febrile stages 
 with an intervening remission. There were present head at In 
 backache, with injection of the eyes and face, together with hemorr- 
 hage from the gums, as had been observed in the primary attaek. 
 
 The want of correlation between temperature and pulse (Fa^r 
 law), upon which clinicians rely as an important diagnostic sign, 
 was seen as a rule in our experimental cases, i. e., after the passage 
 of the first febrile stage. In 1 case produced by the injection of 
 blood, Facet's law was not complied wit h. 
 
 The unne. We have confined our examination of the urine lar 
 to testing for the presence of albumin and to t lie ordinary micros* 
 examination of this fluid. Heat and nitric acid was the met hod 
 in all cases for the detection of albumin, the specimen having lir-t 
 been carefully filtered. 
 
 Under this heading we desire to speak only concerning tin j 
 ence of albumin. AB writers dwell on the importance or a careful 
 examination of the urine in suspicious cases of fever, since the \ 
 ence of albumin in the urine is such a constant sign in yellow fever. 
 Guiteras, who has had a large experience with this disease, says: 
 
YELLOW FEVER. 
 
 129 
 
 "The albumin appears in the urine usually on the third or fourth 
 day of the disease. It may be very transient. In many mild cases 
 the albumin is present only in the urine passed in the evening of the 
 third or fourth day. In many cases it is only a trace.' 7 We may 
 say that the results obtained from examination of the urine of experi- 
 mental yellow fever accords for the most part with the statements 
 above quoted. 
 
 TABLE II. 
 
 Case. 
 
 Albumin during period of 
 incubation. 
 
 Time of ap- 
 pearance of 
 albumin 
 during the 
 attack. 
 
 Time of disappearance 
 of albumin dating 
 from appearance. 
 
 Maximum quantity. 
 
 1 
 
 Mosquito inoculation: 
 
 None 
 
 Hours. 
 42 
 
 Tenth day 
 
 Eight- tenths by volume. 
 
 2 
 
 None 
 
 25 
 
 Eleventh day 
 
 Three-tenths by volume 
 
 3.. . 
 
 None 
 
 82i 
 
 Fifteenth day 
 
 Two-tenths by volume. 
 
 4 
 
 None 
 
 48 
 
 Fifth day 
 
 Distinct trace. 
 
 5 
 
 None 
 
 64^ 
 
 Fourth day 
 
 Light trace. 
 
 6 
 
 None 
 
 43 1 
 
 Third day 
 
 Distinct trace. 
 
 7... 
 
 None 
 
 111 
 
 Eighth day 
 
 Do. 
 
 8.... 
 
 None 
 
 43 
 
 Ninth day 
 
 One-fortieth by volume. 
 
 9 
 
 None 
 
 42 
 
 Twelfth day 
 
 One-twentieth by volume. 
 
 10 
 
 None 
 
 75 
 
 Eighth day 
 
 Distinct trace. 
 
 11 
 
 None 
 
 106 
 
 Fifteenth day 
 
 One-fortieth by volume. 
 
 12 
 
 None 
 
 None. 
 
 
 One-twentieth by volume. 
 
 13 
 
 Blood inoculation: 
 None 
 
 61 
 
 Thirteenth day 
 
 Distinct trace 
 
 14 
 
 None 
 
 17 
 
 Twelfth day 
 
 Do. 
 
 15 
 
 None 
 
 57 
 
 Ninth day 
 
 Do. 
 
 16 
 
 None 
 
 18$ 
 
 Fifteenth day 
 
 One-tenth by volume. 
 
 
 
 
 
 
 1 Albumin did not appear till 36 hours after fever had subsided and persisted for five days. 
 
 In our earlier cases we did not examine for albumin until the onset 
 of the attack. In our last 8 cases (those embraced in this report) we 
 examined daily specimens from the time of inoculation until the attack 
 began, and thereafter we endeavored to examine every specimen 
 passed by the patient. Table II gives the results obtained. 
 
 An examination of the cases presented in this table will show that 
 of the 12 mosquito inoculations the earliest appearance of albumin 
 was at the beginning of the second day in 1 case; during the second 
 day in 5 ; at the end of the second day in 1 ; during the third day in 1 ; 
 during the fourth day in 2; during the fifth day in 1; while in 1 a 
 well-marked case no albumin could be detected till 36 hours after 
 the temperature had reached the normal, i. e., till the second day of 
 convalescence; it then persisted during 5 days. In all 23 specimens 
 of urine were examined in this case during the 6 days of fever, but 
 with an entirely negative result as regards the presence of albumin. 
 An occasional hyaline or fine granular cast could be found in the 
 majority of these specimens. We submit this case of experimental 
 yellow fever as one of especial importance from the clinical stand- 
 point, since the absence of albumin during the attack would have 
 probably led to an error in diagnosis. How very exceptional such 
 cases may be we have no means of knowing. 1 
 
 It will be observed that the quantity of albumin present in this 
 series of cases was very moderate, except in Cases I ana II of Table II. 
 These cases were the only 2 of the 16 that were not placed in bed from 
 
 1 It is of interest to note that this particular individual, 2 weeks prior to successful inoculation and while 
 in quarantine, had an intermittent albuniinuria which lasted 3 days. 
 
 79965 S. Doc. 822, 61-3 9 
 
130 \EB. 
 
 the very beginning of the attack. In the remaining 11. all of whom 
 were kept at absolute rest during the whole period of the fever, the 
 amount of allnunin wai small in r> and inMirniticant in B. We are 
 inclined to believe, therefore, that both the course of the fevc: 
 well as the quantity of albumin, were favorably affected by the ea rly 
 enforced rest of our patiem-. 
 
 In conclusion we desire to invite attention to J nintters which 
 consider of consideimble importance in connection \\ith the p.>^il>le 
 
 importation and propairat i.n of yellow fever. Kir-t. \\e helie\e that 
 the facts herewith presented indicate that the period of incuhation of 
 yellow 1. aMonully exceeds the quarantine period ol :> days, 
 
 and that although exceptional this must not bo left out of considera- 
 tion. Secondly, that our observations eniphaM/.e anew the impor- 
 tance of the recognition by the profe>H>n ,f mild and very mild cases 
 of yellow fever. Guiteras * says: "I can m>t in-M too much upon 
 the importance of the diairnnMs of the iirst case of yellow fever in a 
 locality.'' He adds: " Undoubtedly the cause of the epidemic ol \ el- 
 low fever is to be found in the introduction into a community of cases 
 that are not suspected to be yellow fever." In the lijjht of our ii 
 tigations, we feel constrained to remark that the failure to d. 
 cases of mild yellow fever has been, we believe, the most important 
 factor in the development of the theory of the propagation of this 
 disease by fomites. 
 
 > Report of United States Marine-Hospital Service, Vol. XXVII, 1897-1896, p. 300. 
 
.' 
 
 OR JESSE W. LAZEAR 
 

 CHAPTER 6. 
 
 THE PREVENTION OF YELLOW FEVER. 1 
 
 By WALTER REED, M. D., Surgeon, United States Army, and JAMES CARROLL, M. D., 
 Contract Surgeon, United States Army. 
 
 The prevention of yellow fever since its first importation into the 
 United States in 1693, and especially during the latter half of the 
 past century, has commanded, perhaps, more attention on the part 
 of those who were concerned with matters pertaining to the public 
 health than the prevention of any of the other acute infections. 
 This has not been occasioned by the fact that its total sickness and 
 mortality have exceeded that of other acute infectious diseases, such 
 as typhoid fever or croupous pneumonia, but because rather of the 
 proximity of its source to our shores; the lack of knowledge of its 
 specific agent; the consequent mystery surrounding its origin and 
 propagation; the alarmingly rapid spread and course of this disease, 
 when once it had obtained a foothold, and the high mortality with 
 which its epidemics have generally been attended. Although the 
 duration of its presence in our seaports was plainly limited by certain 
 seasonal conditions, yet during its brief reign July to October its 
 ravages were such as to completely paralyze both the social and com- 
 mercial interests of a given city, and even of an entire section of our 
 countrv. 
 
 The interval between 1793 and 1888 is almost 100 years, but upon 
 the appearance of yellow fever we observe no difference of behavior 
 on the part of the inhabitants of Jackson, Miss., in 1888, from that 
 shown by the citizens of Philadelphia in 1793, except that the terror 
 of the former was greater and their flight from their homes more 
 precipitate than in the case of the latter. 
 
 The recurrence of succeeding epidemics has, therefore, served to 
 increase rather than to lessenthe public alarm. ___ - ! -- - *** 
 
 Tt would li^ difficnl^ tft^Thrr,f>r]ninft with fl.p.r.nrfl,yt,hp. 1o^ nf life 
 occasj^njedj^yj^ by yellow fever during 
 
 the past 208 years. * We have endeavored to collect from the most 
 available sources the mortality caused by this disease, but have been 
 unable to obtain any reliable data for the earlier epidemics. If we 
 confine ourselves to the epidemics which have occurred since 1793, 
 we find that there have not been less than 100,000 deaths from this 
 cause. The greatest sufferer has been the city of New Orleans, with 
 41,348 deaths, followed by the city of PhiladeJpnTa"; with 10.038 
 (ligatfis. The epidemics of 1855, 1873, 1878, and 1879 claimed 7 T 759 
 
 . ^ , , , T 
 
 victims in the city of Memphis. Tenn. From 1800 to 1876, Charleston 
 lost 4,565 of its citizens by attacks of yellow fever. New York, 
 during tHe earlier and later invasions of this disease, has had ,3,454 
 deaths, while the epidemic of 1855 in Norfolk^JVa., caused oVer^OOO 
 
 1 Read at the 29th annual meeting of the American Public Health Association, held in Buffalo, N. Y., 
 Sept. 16-21, 1901. 
 
 131 
 
132 YELLOW FEVER. 
 
 deaths. Durini: our brief occupation of the island of Tuba July, 
 1898-December, 1900), with every precaution brought into 
 to ward off the disease, there have occurred among the officers and 
 men of our Army 1,575 cases of yellow fever, with 231 deal 1 
 
 If we reckon the average mortality at 20 per cent, there have not 
 been less than 500,000 cases of yeflow fever in the United States 
 during* the period frm I7.i:i to I'.MIO. 
 
 Turning for a moment to other conntrie-. \\c find that the ^reai 
 epidemic of IMIII. in the province of Andalusia, Spain. <-au>ed <'>(>. nnn 
 deaths, and thai ' more deaths attended the invasion of the 
 
 city of Barcelona by this disease in ivjl. From 1851 to 1883, the 
 deaths from this cause in the city of Rio de Janeiro \\en 
 while in the city of Habana, between the years 1853 and 1900, 3. r > 
 deaths have been recorded from yellow foyer. 
 
 We have no means of coinput ing the damage done to the conn nenial 
 interests of the United States by epidemics of yellow fever. At the 
 sixtli annual meeting of this association, held in Richmond. Ya.. in 
 1878, Dr. Samuel Choppin. pre-ident of the State board .f health <>f 
 Louisiana, estimated the actual cost of the epidemic of that year to 
 the material resources of the city of New Orleans as $10, 7 "j 
 Dr. Benjamin Lee, the present distinguished occupant of the pi 
 dential chair, at the seventeenth annual meeting of this association, 
 held in Brooklyn, N. Y., in 1889, contributed a paper having the 
 title, "Do the Sanitary Interests of the United States Demand the 
 Annexation of Cuba? From this we quote the following sent* 
 4< A single widespread epidemic of yellow fever w r ould cost the United 
 States more in money, to say nothing of the grief and misery \\hich 
 it would entail, than the purchase money of Cuba." That this 
 was no exaggeration, witness the language of the petition which the 
 chairman of the committee on the etiology of yellow fever, in << in- 
 junction with other prominent members or this association, presented 
 to the President of the United States on November 15, 1897, and 
 again, on November 21, 1898, in accordance with a resolution adopted 
 at the meeting of this association, held at Ottawa. Canada, in i 
 In addressing President M< -Kinley, Dr. Horlbeck said: It i- hardly 
 necessary to call your attention to the serious result^ of the recent 
 epidemic of yellow fever in the States of Louisiana, Mi->i ippi, and 
 Alabama, but we may be permitted to mention the fact that the 
 great epidemic of 1878 resulted in the loss of nearly 16,000 li\e>. and 
 that it nas been estimated that the total loss to the country resulting 
 from this epidemic was not less than $100,000,000." 
 
 The importance of the study of the causative factors entering into 
 the propagation of a disease so capable of (prickly de>t roving the lives 
 of the citizens and wrecking the commercial intere>t> of the < -itie> 
 of the United States could hardly be overestimated. Did time 
 permit, we would be glad to refer to the numerous and valuable 
 contributions made to this subject by the members of the American 
 Health Association. We can only mention the establishment of the 
 National Board of Health and the appointment of the Habana Yellow 
 Fever Commission of 1879 as two of the most important outconn 
 the persistent efforts of this association, following "the deeply tragical 
 events of the summer of 1878." The exhaustive reports made by 
 chailli'- in l^'i, iind by Sternberg in 1890^ must always stand as 
 monuments to the earnest spirit of investigation with which the work 
 pursued. 
 
YELLOW FEVER. 133 
 
 Notwithstanding the importance of the work and the efforts put 
 forth by students in this and other countries, we believe that we are 
 safe in saying that no results had been obtained which would enable 
 us to combat successfully this disease when once imported into our 
 larger centers of population, and no means found to keep it out of 
 our ports except such as would place very heavy burdens upon com- 
 merce. This inability to control the disease grew not only out of our 
 ignorance as to the way or ways in which yellow fever was propagated, 
 but also out of certain false opinions which we had formed as to the 
 mode of its spread. The doctrine of the spread of yellow fever by 
 fomites and by filth had taken such hold on the professional mind 
 as completely to overshadow all other views, and to direct into false 
 channels the work of those who were engaged in the investigation of 
 this disease. The efforts to isolate or to discover the specific agent of 
 yellow fever, if successful, would possibly have greatly simplified the 
 problem ; in the absence of such discovery, the first step in our knowl- 
 edge of how to prevent this disease could only be found, we think, 
 along another line, viz, that of its propagation from the sick to the 
 well. This step we endeavored to take in connection with our col- 
 leagues, Dr. Agramonte and the late Dr. J. W. Lazear of the United 
 States Army, during our recent investigations into the causation and 
 spread of yellow fever at Quemados, Cuba. 
 
 The results of our earlier work relative to the etiology and propa- 
 gation of this disease we had the pleasure of presenting to this asso- 
 ciation at its last meeting, held in Indianapolis, Ind. 1 You will recall 
 that one of the conclusions which we then submitted was as follows: 
 u The mosquito serves as the intermediate host for the parasite of 
 yellow fever." In the same article, we briefly indicated the reasons 
 which influenced us in pursuing this line of investigation, and it is, 
 therefore, unnecessary here to repeat them. 
 
 Continuing our studies, especially as regards the means by which 
 yellow fever is spread from individual to individual, and as to the 
 manner in which houses become infected, we were able, under strict 
 rules of isolation and quarantine, to bring about an attack of yellow 
 fever in 10 nonimmune individuals (and always within the period of 
 incubation of this disease) out of a total of 13 (76.84 per cent) whom 
 we attempted to infect by means of the bites of mosquitoes Stegomyia 
 fasciata that had previously been fed with the blood of yellow-fever 
 patients during the first, second, and third days of their attacks. 
 These results were reported in part to the Pan-American Congress 
 held in Habana during February of this year, 2 and in part to the 
 Association of American Physicians at its last meeting, held in the city 
 of Washington. 3 
 
 It will be seen that we were able to establish in the most conclusive 
 manner that the mosquito does serve as the intermediate host for 
 the parasite of yellow fever. At this same experimental sanitary 
 station we were also able to demonstrate that an attack of yellow 
 fever can not be induced by the most intimate and prolonged contact 
 with the clothing and bedding of yellow-fever patients, even though 
 these articles had been previously thoroughly and purposely soiled 
 with the excreta of such patients. In other words, we were able to 
 
 1 "The EtMogy of Yellow Fever A Preliminary Note. " Philadelphia Medical Journal, Oct. 27, 1900. 
 ;< The Etiology of Yellow Fever An Additional Note." Journal American Medical Association, 
 
 Feb. 16', 1901. 
 8 "Experimental Yellow Fever. " American Medicine, July, 1901. 
 
134 YKI.I.'\\ 
 
 prove that the garments \\orn, and the bedding used, by yellow-fever 
 patients were no more concerned in propagating this disease than the 
 clothing and bedding of patients suffering from malarial fever are 
 erned in the spread of the latter malady. The doctrine of the 
 spread of yellow fever by foiuites having, at the iir>t touch of actual 
 experiment on human beings, burst like a bubble, we may hereafter 
 cast it aside, with other exploded beliefs, to the very great simplifi- 
 cation of the problem how to prevent yellow fever. Indeed, in our 
 opinion, the time has now arrived when the latter problem max be 
 reduce. 1 to measures which shall prexent the pmpairat imi of this dis- 
 ease by mosquitoes. Although this specific a-jvnt of \ello\\ fever has 
 
 not, as yet, teen discovered, this must remain largely a mailer of 
 scientific interest, and does not in the least lessen the efforts \\hieh 
 we, as sanitarians, are now able for the first time to bring into ;t . -tion 
 for the prevention of the spread of this disea.-e. since in dealing with 
 the mosquito we are dealing with the intermediate host which < ; 
 the specific a :ent-from the sick to the \\ell. 
 
 In considering, then, in abroad way, the prevent ion of yell- 
 the natural order would be to give our attention, first, to mea> 
 which will prevent the importation of this disease from 
 places into the seaports of the United States; and secondly, to meas- 
 ures which will most effectually prevent the spread of this di>< 
 provided it should <jain a lodgment in one of the cities of this con 
 
 With your permission, however, we will reverse the order of . 
 sideration above suggested, and will later refer in the briefest manner 
 to the prevention of the importation of yellow fever into the t'i 
 States Irom foreign ports, as this part of "the subject will be prese: 
 by the health officer of the port of New York, who, from lo> 
 rience, will be able to deal more intelligently than we with this part 
 of the problem. 
 
 Since the mosquito, especially that species of stegomyia which has 
 recently been designated by Theobald as Stegomyia fasciuta (formerly 
 know r n to entomologists as Culexfasciatus Fab.), has become so prom- 
 inent a factor in the spread of yellow fever, it becoi 
 consider this insect from the point of view of its identification; its 
 habitat; its breeding places; the length of its generation; its I. 
 of feeding; the influence of temperature upon both its propagation 
 and stinging; the interval after contamination b 
 becomes capable of propagating the disease; the length of time during 
 which it remains dangerous; the measures that should be used nt 
 only to protect the sick against the bites of these insects; but aUo to 
 prevent the latter from infect ing the, healthy individual: and. finally. 
 a consideration of the several agents which may be successfully 
 
 employed both to prevent the breeding of moMiuitnes MS \\ell a's 
 
 ted toward their de-t net ion in the adult si 
 
 Aside from the standpoint of scientific inter, ;iinly a 
 
 matter of hygienic importance, in taking \i\> the <pie-iim of how to 
 prevent the spread of yellow fever, when imported into the, Tniicd 
 States, that trie health authorities of our several << .-md. 
 
 indeed, of some of our inland i honld bo able to determine 
 
 whether the only species of mosquito, which, up to the pre>ent < 
 has been shown capable of conveying yellow fever, is or is Dot 
 in these cities. If it should hereafter be pi<.\en that only spcci. 
 the genus stegomyia are capable of net in-/ a# intermedi.. for 
 
YELLOW FEVER. 135 
 
 the specific agent of yellow fever, as appears to have been demon- 
 strated for the geuus anopheles in the spread of malaria, the presence 
 or absence of the former genus will definitely determine whether 
 yellow fever will or will not spread in a given locality. The presence 
 or absence of mosquitoes that can propagate the disease is the only 
 intelligible explanation of what has heretofore been considered an 
 inexplicable problem, viz, the capability of this disease to propagate 
 itself in certain localities, while in other places it could be introduced 
 with perfect impunity to the public health. In other words, our 
 present knowledge of this question solves, at last, the problem of the 
 portability or nonportability o'f yellow fever. 
 
 Description of mosquito. The identification of stegomyia fasciata, 
 Theobald, should not be difficult. This mosquito, when examined 
 closely with the naked eye and especially with a pocket lens, is a 
 rather striking-looking and handsome insect. (Fig. 1.) Its most 
 conspicuous markings are the broad semilunar silvery stripe, which 
 is seen on the lateral surface of the thorax, and the white stripes at 
 the bases of the tarsal joints. These may be readily distinguished 
 with the naked eye. The bands on the hind legs are especially well 
 marked, and occasionally the entire fifth hind tarsal joint is seen to 
 be of a pure silvery white. The four stripes of silvery scales which 
 are seen on the posterior surface of the thorax serve to distinguish 
 this species from all other mosquitoes, except stegomyia signifer, 
 Coquillet, in which, however, as we have been informed by Mr. L. O. 
 Howard, the curved thoracic band is very narrow and of a somewhat 
 different shape. Examined with a hand lens, the four stripes are 
 seen to consist of two lateral, distinct silver lines the continuation 
 of the semilunar, broad stripes and two fine, white lines situated 
 between these, and which require that the insect shall be held in the 
 proper light, in order that these delicate threads may be distinctly 
 seen. The lateral surface of the thorax is also marked by several 
 silvery dots and the abdomen by distinct white stripes. This de- 
 scription applies to both sexes. In the female, the palpi are short, 
 as in the genus culex. The proboscis is of a dark blackish-brown 
 color and is destitute of a whitish band near the middle. In the 
 male (fig. 2), one of the front tarsal claws bears a tooth on the under 
 side, while the other claw is destitute of such marking. In the 
 female, both front tarsal claws bear a distinct tooth near the base 
 of the under side of each. 
 
 Habitat. We have found this mosquito in all of the principal cities 
 of Cuba, and have received specimens from a number of the smaller 
 towns on this island. According to Howard 1 it has been found at 
 Kingston, Jamaica, on the Isle of Pines, and at Bluefields, Nicaragua. 
 He also reports that Theobald has received specimens of this insect 
 from Italy, Greece, Spain, Portugal, Gibraltar, and Malta. , In the 
 United States, Howard reports its presence a t New Orleans, Natchi- 
 tochez, and Napoleonville, La., ; in eastern Texas ; Hot Springs, Ark. ; 
 Pelham, Ga. ; and from Virginia Beach, near Norfolk, Va. To this 
 we can add Augusta, Ga., from which city we have recently received 
 specimens of stegomyia fasciata through the courtesy of Dr. T. O. 
 Oertel of that city. Dr. Durham, of the English commission for the 
 study of yellow fever, kindly showed us specimens of this insect which 
 
 1 "Mosquitoes," etc., by L. O. Howard, New Yorti, 1901. 
 

 
 he had collected at Para, Hra/.il. and a; \arious places alon<: the 
 Amazon River. It will be seen, then-tore, that stegomyiafasciata has 
 a \\ide distribution in the \\armcr countries of the globe, and espe- 
 cially at low altitudes. A more exact kno\\ledire of the distribution 
 of this mosquito in the United States is, \\e think, a matter of con- 
 siderable practical importance. 
 
 Breeding places. In our search for the larvae of this insect we have 
 found them in the following place.-: I rain-\\ater barn-U : 
 
 in sagging pit ters containing rain \\ ater; ('.\ ) in tin cans that had been 
 used for re i no v ing excreta ami which still contained a small amount of 
 fecal matter: i Din cesspools; (5 in tin can- placed about table le-- 
 io prevent the inroads of red ants; (6) in the collection of \\-.\\- 
 the base of the leaves of the agave americana; (7) in one end 
 
 Fio. 1. Stegomyla fasciata; female, a, Front tarsal claw. 
 
 horse trough that was in daily use. It follows that ste^omvia. like 
 culex, will oreed in any collection of still water, rain or hydrant, and 
 that the presence of fecal matter does not seem objection able. Indeed, 
 we have been in the habit of adding a \ry small quantity of the latter 
 to our breeding jars, as it has seemed to hasten the development 
 of the larvae. In water, however, which contains much su-pended 
 soil muddy water the larvae, in our experience, do not llouri>h. 
 but die off rather rapidly. 
 
 Deposition of eggs. The insect, lays her e.^s durinir the niirht, and, 
 unlike culex. \\hirh deposits its eggs in boat like masses, stegomyia 
 extrudes her e^^ <>n tho surface of the water in pairs, in p-oiij 
 
 thn r more, or singly: in llii- respecl re-em blin.ir anoph- 
 
 (Fig. 3.) Exceptionally, the eggs are deposited in a rather close- 
 
YELLOW FEVER. 137 
 
 lying mass. (Fig. 4.) The whole batch is laid in one night, or 
 extending over two or three nights. The number of eggs deposited 
 varies from about 20 to about 75 rarely a larger number. Sixteen 
 careful counts gave an average of 47 eggs. At the same time that the 
 female deposits her eggs, she frequently, but not always, discharges a 
 fluid which forms a very thin film over the surface of the water, which 
 possibly assists in floating the eggs. The latter are of a jet-black 
 color and, to the naked eye, cylindrical in shape, one end of the egg 
 being rounded and blunt, while the other is slightly pointed, the 
 whole resembling closely a Conchita cigar. They measure about 
 0.65 mm. in length by 0.17 mm. in width at the broadest part. Under 
 a low power, the surface of the eggs is seen to be marked by tolerably 
 regular six-sided plates, each of which is further marked in the center 
 
 FIG. 2. Stegomyia fasciata; male, a, Front tarsal claw. 
 
 by a little round elevation, which gives to the surface of the egg a 
 decidedly roughened appearance. (Fig. 5.) Under this low ampli- 
 fication it is also seen that, while one side of the egg is somewhat con- 
 vex, the other is flat or slightly concave and that a cross section of 
 the egg would present the appearance of a triangle instead of that of 
 a cylinder. This flattening of the surface of the egg does not appear 
 to extend quite to the ends, which are round in shape. Although 
 floating perfectly if left undisturbed, any agitation of the water, 
 especially of a rough character, is apt to cause some or a majority 
 of the eggs to sink. If by slight pressure the egg is pushed beneath 
 the surface of the water it at once sinks and does not rise again. 
 This sinking of the eggs does not interfere with their subsequent 
 hatching, as in our experience submerged eggs furnish about as many 
 larvae as those which are left floating on the surface. 
 
138 
 
 \ ER. 
 
 The resistance of stegomyia's eggs to external influences is worthy 
 of note. Drying seems to be but Tittle injurious to their subsequent 
 fertility. We have found that eggs dried on lilter paper, and kent 
 for periods of from 10 to *n day-, will promptly 
 hatch \\hen again submerged in water. Pried 
 eggs brought with us from llabana. in Feb- 
 ruary, were easily hatched (luring the month 
 of May in Washington, furnishing about (>0 
 per cent of the usual number of larva* hatched 
 from fresh eLTgs. Free/ing doefl r.ot destroy 
 the fertility of the eggs; although free/.ing with 
 a mixture Of salt and iee for :in minnto bafl 
 :d times seemed to prevent -ulequent 
 hatcliing; on one occasion a bat eh of 1 .~>5 eggs, 
 freslilv deposited, which were fro/en at a 
 ture of 17 C., for one hour, then thawed out at room tempera- 
 ture and placed in the incubator at 35 C., began to hatch on the 
 sixth day. the majority furnishing active larvae on the eighth day. 
 In another observation, freshly deposited eggs, 
 frozen at 17 C. for half an hour on two succes- 
 sive days, began to hatch on the third day as usual 
 at incubator temperature. The resistance of ste- 
 gomyia's eggs to drying for a period of three 
 months would appear to demonstrate that this 
 
 10. 3. Steromyla fasclata. 
 Btch of flfiy-iwo eggs asde- 
 !-v : toffi f, 
 
 UjMtefed 
 
 FIG. 4. Stegomyia fascl- 
 ata. Forty -eight eggs 
 deposited In a 
 lying mass. Enlarged. 
 
 appear 
 
 genus of mosquito could survive the winter in 
 Habana without the presence of hibernating 
 females. Doubtless the genus is preserved in botn 
 ways. It is probable that the same could occur in 
 our extreme southern latitudes. 
 
 Length of generation. The impregnated female, 
 having obtained a meal of blood, proceeds to de- 
 posit her eggs, in captivity, after an interval vary- 
 ing in our experience from 2 to 30 days as a rule, the eggs are laid 
 within 7 days; sometimes a second or third meal of blood is taken 
 before any eggs are laid. Eggs placed .under favorable conditions of 
 
 warmth i. e., summer or incu- 
 bator temperature begin to 
 hatch, as a rule, on the third 
 day, the period extending to 
 about 1 week. The larval 
 requires 7 or 8 days, and the 
 pupal stage about 2 days. The 
 period for the generation may 
 oe stated, therefore, as follows: 
 Incubation. Mday>: larval stage, 
 7 days; pupal, 'u day-: total. 
 12 days. .As the . 'in to 
 
 hatch before the expiration of 
 the third day, we generally ob- 
 tain a few mosquitoes on the 
 eleventh day. The shortest period of development observed by us dur- 
 ing summer weather in Cuba was incubation. *J days; larval stage, (i 
 days; pupal, 36 hour*.; making the total length of this generation \\\ 
 days. TnU short period we believe to be quite, exceptional. Tim 
 
 Fio. 5. Stegomyia fasciata. Newly deposited 
 X 60. a, Empty shell from which larva hasesoa 
 
YELLOW FEVER. 
 
 139 
 
 FIG. 6. Stegomyia fasci- 
 ata. Full-grown larva 
 enlarged. 
 
 first fully developed insects begin to emerge on the eleventh or twelfth 
 day, and the whole number have reached maturity by the fifteenth 
 or eighteenth day after deposition of the eggs. The young larvae, in 
 emerging, rupture the shell at a point about one-fifth the length of 
 the egg from the larger end. This cap-like end can be frequently 
 seen turned back and still adhering to the rest of the shell. (Fig. 5.) 
 The larva and pupa of stegomyia (figs. 6 and 7) resemble fairly 
 closely those of culex, and the larvae maintain the same relative 
 position to the surface of the water; i. e., while in 
 the act of breathing they assume a vertical posi- 
 tion, with the head directed downward. 
 
 Influence of temperature on propagation. We 
 have just seen that at summer temperatures the 
 time required for a complete generation of this 
 insect is from 11 to 18 days. We may say that 
 at an average temperature of 75 F., or over, 
 stegomyia multiplies abundantly. Exposure to a 
 cooler temperature, even for a short time daily, 
 much retards the development of this mosquito. 
 Thus, a batch of 51 eggs kept at 35 C., but which 
 were placed in a cool chamber. at 20 C. for two 
 hours daily during the whole process of develop- 
 ment, although furnishing a few larvae at the end 
 of the third day, were not all hatched until the 
 eleventh day. The first pupae appeared on the 
 fourteenth day and the first mosquito on the 
 nineteenth day; the whole process being completed in 27 days, instead 
 of the usual 15 to 18 days. The loss of insects was about 50 per cent. 
 Eggs kept at a temperature of 20 C. (68 F.) do not hatch, in our 
 experience. Newly hatched larvae kept at this temperature develop 
 very slowly and require about 20 days to reach the pupal stage. Mos- 
 quitoes developed under such conditions are feeble, and but few 
 arrive at maturity. Young larvae kept at 10 C. (50 F.) have failed 
 to reach the pupal stage, although some growth takes place. In one 
 experiment more than 50 per cent were dead at the 
 end of two weeks, and none survived the thirty-sec- 
 ond day. Half-grown larvae and pupae exposed to a 
 temperature of 20 C., and even as low as 10 C., con- 
 tinue to develop slowly, but the few insects which 
 escape drowning have, as a rule, been of feeble 
 strength and have refused to bite. Although the 
 reduction of the temperature to the freezing point, 
 or below, would not necessarily destroy the vitality 
 of the eggs of this genus of mosquito, it should be 
 remembered that a reduction of temperature to 68 F., 
 or below, for even a few hours of the 24 will much 
 retard the development of the generation. At a temperature less than 
 68 F. the eggs of this insect nave ceased to hatch. 
 
 Influence of temperature on biting. While the nonimpregnated 
 female does not appear to bite, the impregnated female is generally 
 ready to bite on the second or third day of her existence; they very 
 rarely suck blood on the first day. This species of mosquito, when 
 not deprived of its liberty, although occasionally biting during the 
 morning hours, has, in our experience, been especially active from 
 the hour of 4 p. m. till midnight. In captivity, the hungry impreg- 
 
 FIG. 7. Stegomyia 
 fasciata. Pupa, en- 
 larged. 
 
140 Y1-1LLOW FEVEB. 
 
 nated female will bite at any hour of the day or night. The meal of 
 blood appears to have been thoroughly digested on the third day. 
 when the bisects, if applied to the surface of the skin, can l>e again 
 readily induced to feed. When freed in a room, the female docs not 
 appear to bite a second time till about five, or even seven, days have 
 elapsed. 
 
 As regards the effect of temperature in the stinging of S/M/ 
 fasciata, the results of a number of observations made by u> >how 
 Miuito will bite at teni|)eral ures of 62 F. and al>o\c. At 
 temperatures helow this point, we have not, as yet, succeeded in in- 
 ducing even very hungry females to suck blood. W. herefore, 
 say that observations thus far made appear to show that * s 
 
 myia/OA. iiile not breeding at temperatures below (>S F., will 
 
 still bite at a temperature as low as 62 F., but probably not at lo\\ er 
 temperatures. 
 
 If this insect is concerned in the propagation of yellow foyer, it is 
 now unite apparent why an epidemic of this disease >h<>uld fall ti a 
 low ef)h in the city of New Orleans during the month of November, 
 with a mean temperature of 61.8 F., and practically cease in Decem- 
 ber, with a mean temperature of 55.3 F. A careful study of the 
 charts herewith submitted (figs. 8 and 9), showing the monthly mean 
 temperatures of the cities of llabana and New Orleans and Ilahana 
 and Kio de Janeiro together \\ith the relative monthly mortality from 
 yellow fever in these cities, will prove of interest, \\e think, as show- 
 ing better than laboratory observations the general effect of teni| 
 ture upon the breeding and biting of Stegomyiafasciata. In the light 
 of recent researches, we can now understand that while yellow I 
 can, and does, prevail during the entire year in Ilahana and Hi 
 Janeiro although at a comparatively low ebb during the winter 
 months it can not propagate itself in New Orleans from December 
 to May. 
 
 Interval after contamination before the mosquito becomes dangerous. 
 In our experimental work on human beings, we have n <led 
 
 hi inducing an attack of yellow fever by the bites of mosquitoes which 
 had been kept less than 12 days after contamination. The same 
 bisects which failed to convey the disease on the eleventh < lay were 
 capable of so doing on the seventeenth day after infection. Th is i n t < r- 
 val of about 12 days, which appears necessary for the development 
 of the parasite within the mosquito, plus the period of incubation, 
 agrees with the time that has been ooserved to elai>>e between the 
 introduction of an infecting case into a locality and the occurrence of 
 the first secondary case, viz, two to three weeks. 
 
 After the mosquito has once become dangerous, how long it remains 
 capable of conveying the disease, although important. ha> not been 
 rmined. We have reported cases of \cllo\v iVver caused by the 
 bites of stegomyia at interval^ varying from \'l to f>7 da\s after con- 
 tamination. Herethedangerousintervalwas4.~M|.i\ >,but a>ncoi thc-c 
 
 ts lived until the seven ty-first day after biting a yell. 
 patient, the dangerous interval would here be prolonged to59d 
 little over 8 weeks. In our experience, the. mlccird in-cd appe.-s 
 live about as long as the noninfected mosquito, so thai the answer to thk 
 que-tion would depend upon the length of life of the mosquito. This 
 we do not know. While in captivity, the majority of moMjiiito. 
 
YELLOW FEVER. 141 
 
 not survive, with the best of care, more than about five weeks, and 
 many die within half of this tune; we are ignorant as to the length of 
 time during which they may live when under natural conditions. 
 Certainly, during summer weather this will depend largely on the 
 opportunity which the mosquito has of obtaining access to water. 
 
 Measures to prevent the spread of the disease when imported. A case 
 of yellow fever having been imported into one of our seaport cities, 
 we are now prepared to discuss the measures that should be taken 
 to prevent its spread. The problem resolves itself into the simple 
 one of excluding mosquitoes from access to the sick individual and 
 of destroying those insects that have already become infected. We 
 can leave out of consideration any danger from wearing apparel or 
 baggage, which, in our opinion, may be dismissed as harmless. 
 
 The fear that has been entertained that infected insects may be 
 imported in boxes or trunks we believe to be absolutely groundless, 
 and this for the simple reason, as shown by numerous observations 
 made by us, that mosquitoes, when deprived of water, die within a 
 few days. Even if allowed to fill themselves with blood immediately 
 before the experiment is begun, and then deprived of water, practi- 
 cally all are dead by the expiration of the fifth or commencement of 
 the sixth day. We may say that of a large number of insects tried 
 in this way only one female has survived until the sixth day, and 
 then in a feeble condition. Males and females which have been living 
 on sugar and water, or fed two days before on blood, if deprived of 
 water and food, begin to die after 24 hours, and all are dead on the 
 fourth morning. Free access to water, therefore, is necessary for the 
 existence of this mosquito. 
 
 Add to the deprivation of water the chances of injury to so frail 
 an insect packed in with articles of clothing, etc., and we see that 
 infected mosquitoes can not be imported alive in baggage that has 
 been five days en route. 
 
 As the first special measure of prevention, then, we should give 
 our prompt attention to the protection of the sick individual against 
 the bites of mosquitoes. This can best be accomplished by thorough 
 screening, without delay, of the windows and doors of the room 
 occupied by the patient and with as little disturbance as possible, so 
 that any insects already present in the room may be prevented from 
 escaping. As it will not be feasible to make use of any of the 
 destructive agents against mosquitoes already within the patient's 
 room until recovery, every precaution should be used to see that the 
 insects do not escape in opening and closing the door. Screens at 
 windows should not, for this reason, be movable. As it is possible 
 that mosquitoes that have already bitten the sick individual may 
 have escaped into other apartments of the house, these should be 
 closed tightly and subjected either to sulphur or to formaldehyde 
 disinfection or to the fumes of burning pyrethrum. According to 
 Dr. Gorgas, the efficient health officer of Habana, preference is given 
 to pyrethrum powder, burned in the proportion of 1 pound to 1,000 
 cubic feet of air space. 1 He, however, adds : 
 
 As the pyrethrum powder, even in this large quantity, does not certainly kill all 
 mosquitoes, the room is opened at the end of three hours and the mosquitoes on the 
 floor swept up and burned. 
 
 i Medical Record, New York, vol. 60, No. 10, Sept. 7, 1901. 
 
142 
 
 Y Ml. LOW FKVKR. 
 
 We have mentioned above, in the order of their eiririenry, the 
 agents which are most destructive to stegomyia. According to our 
 
 observations, an exposure for one and a half hours t<> sulphur fumi- 
 gation, in a well-closed room, in the proportion of 1 pound to 1,000 
 
YELLOW FEVER. 143 
 
 cubic feet of air space, will suffice effectually to destroy all mosquitoes. 
 Formaldehyde gas is not quite so efficient. With Trenner's formal- 
 dehyde generator, charged with formalin, 900 c. c.; glycerin, 9 c. c.; 
 methyl alcohol, 360 c. c., which we have found quite reliable for the 
 destruction of bacteria, an exposure of not less than three and pref- 
 erably four hours is required in order to kill these insects in a tight 
 room having 2,800 cubic feet capacity. Pyrethrum powder, if 
 burned in the proportion of 4 ounces to 1,000 cubic feet ol air space, 
 will stupefy all mosquitoes at the expiration of one hour, so that 
 they will fall to the floor in a helpless condition. If used, however, 
 the precaution above recommended by Dr. Gorgas should be strictly 
 followed that is, the room should be opened at the end of three 
 hours and all insects carefully swept up and burned. The practice 
 of destroying all mosquitoes in adjoining houses, as carried out in 
 the city of Habana with such excellent results, we consider of the 
 greatest importance, since only in this way can we hope to destroy 
 infected mosquitoes, and thus preVent the occurrence of secondary 
 cases. In other words, relying upon the well-known slow progress of 
 the spread of yellow fever, we seek to catch and destroy all mosqui- 
 toes within a given radius of the first case. If secondary cases should 
 occur, the same hygienic measures should be rigorously enforced 
 along the lines above indicated. UpOn the completion of the case, 
 the room occupied by the patient should be disinfected, and in a 
 matter where so much is at stake we believe that sulphur should be 
 given the preference as a disinfectant. In case of death, the body 
 should be carefully screened against mosquitoes, as stegomyia will 
 bite the dead body and might in this way-acquire the parasite. 
 
 We have said nothing about the protection of nonimmune individ- 
 uals who enter the patient's room or housd*, since, if the case under 
 consideration is the infecting case, no danger is incurred. As the 
 duration of the attack is short, generally less than 10 days, the pa- 
 tient's room will have been disinfected and the infected mosquitoes 
 destroyed before they have become susceptible of conveying the dis- 
 ease to others. We desire to emphasize the fact that the interval 
 elapsing between the infection of this mosquito by biting a case of 
 yellow fever and the time when it has become capable of conveying 
 the disease, viz, about 12 days, is of the utmost importance in our 
 efforts toward stamping out yellow fever at its very commencement, 
 since it furnishes a nondangerous interval during which all infected 
 insects should be easily destroyed. It thus makes the control of 
 yellow fever hereafter a simpler and more certain matter than the 
 suppression of an outbreak of any of the other acute infectious 
 diseases. If nonimmunes entering an infected house desire protec- 
 tion against the bites of stegomyia, this may be obtained by rubbing 
 all exposed surfaces of the body, including the ankle surfaces, with 
 spirits of camphor, oil of pennyroyal, or a 5 per cent menthol oint- 
 ment. The protective effect of these substances is, however, only 
 temporary. 
 
 What we have already said concerning the breeding places of 
 Stegomyia fasciata should sufficiently indicate the general hygienic 
 measures that should be taken in order to prevent the spread of yellow 
 fever. These should consist in enforcing such measures as will effec- 
 tually destroy the breeding places of this very domestic mosquito. 
 
144 YELLOW FEVEB. 
 
 The methods adopted by the chief sanitary officer of llabana. durini: 
 the present year, may be taken as a model by our sanitary officials. 1 
 It should not be .'ii that a well-drained and well-sewered city. 
 
 with a pure v ;Tl v an ^ ( 'l (i an Mreets lias no pr.itcction against 
 
 the spread of yellow fever. pr\ ided rain-water barrels and other col- 
 ons of water are present , in which stegomyiamay breed. In one 
 of the forts, on the outskirts of llabana, which was other\\i-e in an 
 ilent san .lni..n. \\> fnnnd t housands of Stegomyiafasciata 
 
 breeding in tin oana placed about the legs of a table in an oil 
 kitchen. Our con. ept ion of yellow fever, therefore, as a "filth" dis- 
 ease must be abandoned, and our attention turned to yellow fever 
 as a mosquito-borne disease. In illustration of \\hat may be accom- 
 
 1*111 i i .ill.. .. i i r 
 
 plished by sanitation based on the latter method of propagation, we 
 present herewith a chart (fig. 10) showing the actual monthly 
 tality from yellow fever in llabana, for the period from isso to i 
 
 and also for the years 1900 and 1901. Comparing the mortality from 
 ix'.w, which was the most favorable ye. -How 
 
 : that Habana had experienced in L.M) years, with 1!H. during 
 which sanitation, based on the demonstration that yellow fev< 
 propagated by the mosquito, lias been enforced. \\e find a reduction 
 in mortality of 83.3 per cent in favor of the present epidemic 
 
 . 1 to Aug. 31); or if we compare the mortality fr the epidemic 
 year 1900 with the present year we observe a still greater reduction 
 in favor of the latter, viz, 411 per cent. 
 
 The sanitary regulations put into force February 15, Hni. by 
 Dr. Gorgas, resulted in freeing Habana from yellow fever within :; 
 months, so that for a period of 54 days May 7 to July 1 no 
 occurred. On the latter date, the disease was brought into Ilai 
 from Santiago de las Vegas, and, according to Gorgas, has l>een intro- 
 duced into the city at least a dozen times from this and ot her 
 In spite of these new sources of infection, July has only furnished 
 four cases, with one death, and August eight cases, with two deaths. 
 If such admirable results, under new methods of sanitation, have been 
 obtained in this hotbed of yellow fever, we can not believe that the 
 intelligent and efficient boards of health of pur cities will again nermit 
 this disease to assume an epidemic form in any city of the United 
 States. 
 
 Measures directed against the importation of yellow fever into the 
 United States. Under the admirable system of inspection and rep' 
 as carried out by the Marine Hospital Service, the appearaix e of yel- 
 low fever at any foreign port is promptly reported for the informat ion 
 of the health authorities of our several Atlantic ports. We may, 
 therefore, divide foreign ports within the so-called epidemic 
 into (a) infected, and (o) noninfected ports. Heretofore, no distinc- 
 tion has been made by the health officers of our southern ports as 
 regards quarantine regulations from April 1 to November 1, between 
 infected and noninfected places. All ports within the epidemic zone 
 of yellow fever were considered as being infected places, and hence pas- 
 sengers and vessels were subjected to quarantine and to disinfection 
 of both baggage and cargoes. 
 
 With our present knowledge of the way in which yellow fever is 
 propagated, we believe that in the treatment of passengers, as well 
 
 * Medical Record, New York, vol. 60, Sept. 7. 1001. 
 
YELLOW FEVEK. 
 
 145 
 
 as of cargoes, a sharp distinction should be made, first, between 
 infected and noninfected ports; and, secondly, in the case of vessels 
 sailing from infected ports, between those that have received their 
 cargoes and passengers in midstream and those that have loaded at 
 the wharf. 
 
 fleatfa 
 
 months, 
 
 anuary: 
 
 JUMA. 
 
 October. 
 
 eeemder. 
 
 a 
 
 Ztegrees. fl&ner&teff. 
 
 We believe that no quarantine restrictions should be placed upon 
 
 either passengers or cargo from noninfected ports. In the case of a 
 
 vessel loading in midstream at an infected port by means of lighters, 
 
 we believe that she can only receive infection in one way, i. e., by 
 
 79965 S. Doc. 822, 61-3 10 
 
146 YELLOW FEVER. 
 
 passengers who have been exposed to yellow fever on shore, and who. 
 coming aboard, may thereafter be seized with the disease. The po.<i- 
 hility of infected mosquitoes reaching the vessel, either by flight or 
 by means of lighters, may be considered as highly improbable. 
 
 Vessels, loaded under the foregoing circumstances (i.e., by lighters 
 in midstream), and arriving at our ports without yellow fever devel- 
 oped en route should have their DOniinmune nas-enircrs quarantined 
 for live days, counting t he time consumed by the voyage as pa it of the 
 quarantine period, and should be allowed to discharge their car 
 without delay. If the disease has developed en route amonir ciw\ 
 or passe: he siek should he promptly removed; the forecastle 
 
 taterooms, as the case may he. thoroughly disinfected with sul- 
 phur or formaldehyde gas, and the vessel allowed to proceed to her 
 wharf. 
 
 On the other hand, if the vessel has received her cargo at the wharf 
 of an infected port, there is a possibility that she may have recen ed 
 infection in three ways: Kirst, either by contaminated mosquitoe< 
 that have bitten a case of yellow fever in the immediate vicinity on 
 shore; secondly, by mosquitoes that have become infected from" bit- 
 ing a yellow-fever patient present on another vessel loading at the 
 same, or at an adjacent, wharf; or, thirdly, by some individual who 
 has acquired the infection on shore and afterwards taken pass at 
 the vessel. 
 
 In our opinion, however, the chances of infection of a vessel by 
 contaminated mosquitoes coming aboard from a house or ship in 
 close proximity are very slight; although such a possibility must be 
 admitted, and the further possibility that recently infected m< >s< \\ ; 
 may have sought refuge on the vessel during the night preceding her 
 day of departure. It is also possible that a case of mud and 1 
 undetected yellow fever may occur on board, and be the sour* 
 the infection of mosquitoes already present in the vessel. 
 
 Under these circumstances, if a sufficient number of days have not 
 elapsed between her port of departure and port of arrival in the United 
 States, i. e., 16 to 21 days, to demonstrate the presence of inf 
 mosquitoes by the occurrence of a case or cases of yellow fever en 
 route, we know of no way of absolutely excluding the possibility of 
 importation of the disease by such a vessel than by the detention of 
 all nonimmune passengers for such number of days a.s will show their 
 freedom from infection, and by careful disinfection of crew's and 
 passengers' quarters. 
 
 If more than 20 days have elapsed during the voyage, without the 
 occurrence of yellow fever, we see no good reason why either pa 
 gers or vessel should be detained. 
 
 We have said nothing about the disinfection of the vessel' 
 for the reason that we do not consider this to be necessary. The only 
 possible excuse for subject in<: the cargo to disinfection would be the 
 lear of the presence of infected mosquitoes in the vessel's hold, pro- 
 vided she had loaded at the wharf of an infected port. In this 
 instance, if the voyage has consumed five or more days, all mosqui- 
 toes contained in the hold will have died: for, as we have already 
 pointed out, Stegomyia fasciata lives only a few days if deprived of 
 water. We can not too strongly insist that the danger of importation 
 of yellow fever into the United States lies, not in cargo or personal 
 
YELLOW FEVER. 
 
 147 
 
 8 
 
 Mynter cf deaths 
 
 ft 8 
 
 January 
 
 Jtyust- 
 
 October - 
 
148 YELLOW l-T.YKK. 
 
 baggage, but in the individual sick with that disease. With our 
 present knowledge of its propagation, personal baggage should no 
 longer be subjected to disinfection, and, with our in. !>ility to 
 
 prevent its spread l>y m application, instances should 
 
 be few ami exceptional when a vessel coming from a yellow-fever port 
 should be delay cd lonuvr than will he necessary to remove her n>n- 
 iinmune passenL t yet completed their period of live 
 
 days since leaving the port of departure. 
 
 The chief duty of (|iiarantine officers hereafter will coiiM-t in the 
 i of mild or very mild cases of vellow fever. J 
 
 [mental yellow fever produced by thebiteof flffcyomyw 
 fasc'uitn. we nave, elsewhere. 1 jx'inted out that 4, or .'>."> \ 
 
 mild >r verv mild in character, and have indicated the dillicnlty 
 of making a positive diagnosis in such cases. 
 
 In discu^>iuLT the period of incubation of experimental yellow f 
 we have shown that in i;.i; per cent of our cases the period of incu- 
 bation exceeded the usual quarantine period of live days. 1: add 
 Carter's cases to those observed by ourselves, we find that of iM 
 the period of incubation exceeded five days in 3, or L2.5 per cent. 
 
 We can thus readily see what great danger heretofore lay in the 
 passage through quarantine of just such mild cases, or of those ha 
 an incubation stage of more than five days. 
 
 While the exclusion of such cases is of thegreate-t importance, we 
 doubt whether, with our improved knowledge of how to prevent the 
 spread of yellow fever, it would be advisable to place a greater hunlen 
 upon ships' passengers by extending the quarantine period to more 
 than five days. It appears to us rather that in view of the trou hie- 
 some delays to which passengers and vessels from yellow-fever : 
 have been subjected in the past, the time has now arrived when. 
 standing upon more solid ground, we will be justified in seeking in 
 every way to lessen as much as possible the restrictions placed by 
 present quarantine regulations upon the ship's cargo, while we add 
 nothing to those of the passenger. 
 
 To this end a most important part will have been accomplished if 
 we can persuade the sanitary authorities of our sister republic, M. \i ... 
 and of the Central and South American States, to join us in the adop- 
 tion of more enlightened methods for the suppression of this widely 
 prevalent epidemic. 
 
 ' Experimental Yellow Fever." Transactions of the Association of American Physicians, 
 
 Vol. 
 
CHAPTER 7. 
 
 THE ETIOLOGY OF YELLOW FEVER A SUPPLEMENTAL NOTE. 1 
 
 By WALTER REED, M. D., Surgeon, United States Army, and JAMES CARROLL, M. D., 
 Contract Surgeon, United States Army, of Washington, D. C. 
 
 Informer contributions to this subject, we have shown by observa- 
 tions made on human beings that yellow fever may be produced in 
 the nonimmune in dividual either by the bite of the mosquito (1) (genus 
 Stegomyia) that has previously been permitted to fill itself with the 
 blood of a patient suffering with yellow fever, during the first three 
 days of the attack, or by the subcutaneous injection of a small quan- 
 tity of blood (2) (0.5 to 2 c. c.) drawn from the general circulation 
 of such a patient during the active stage of this disease. For further 
 particulars regarding these observations the reader is referred to the 
 original papers. 
 
 Although these experiments have demonstrated that the specific 
 agent of yellow fever is present in the blood, we may say that the 
 prolonged microscopic search which has been made by other investi- 
 gators, as well as by ourselves, both with fresh and stained prepara- 
 tions of blood, taken at various stages of this disease and during early 
 convalescence, has proved thus far entirely negative. We may 
 add that the efforts which we have made with reasonable hope of 
 reward, both in the bodies of infected mosquitoes, dissected in the 
 fresh state, as well as by serial sections of the hardened insect, have 
 likewise given no results which we consider worthy of record at the 
 present time. Leaving out of consideration, therefore, for the time 
 being, the further microscopic search for the specific agent in the 
 blood of the sick and in the bodies of infected mosquitoes, we desire 
 to call attention to some additional observations bearing on the 
 etiology of the disease, which one of us (Carroll) has recently made 
 at Las Animas Hospital, Habana, Cuba, and at Columbia Barracks, 
 near Quemados, Cuba. 
 
 We here desire to express our sincere thanks to Dr. William H. Welch, 
 of the Johns Hopkins University, who, during the past summer, 
 kindly called our attention to the important observations which have 
 been carried out in late years by Loeffier and Frosch relative to the 
 etiology and prevention of foot-and-mouth disease in cattle. In the 
 course of their investigations concerning a reliable method of immu- 
 nization in this disease, the authors had occasion to dilute and after- 
 wards to pass several times through a porcelain filter, lymph which 
 had been collected from the blebs present in the mouth and on the 
 feet of cattle sick with foot-and-mouth disease (4). 
 
 These observers, having already ascertained that immunity could 
 be conferred upon cattle by the subcutaneous or intravenous injec- 
 tion of one -fortieth to one-fiftieth c. c. of pure lymph previously 
 
 Read before the third annual meeting of the Society of American Bacteriologists, Chicago, 111., Dec. 31, 
 1901, and Jan. 1, 1902. 
 
150 YELLOW FEVER. 
 
 mixed with 1 c. c. of the defibfinated blood of an animal that had 
 recently recovered from the disease, desired to find out whether the 
 injection into calves of given quantities of this filtered ami hacteria- 
 free lymph would not. also, enable them to confer immunity of. 
 perhaps, a higher degree upon cattle. 
 
 The roults were quite surprising, since it was sho\\ n that eaKes 
 \\hich had received one-tenth to one-fortieth c. C. of the diluted and 
 filtered lymph ;< 1 foot-and-mouth di>ea>e ju-t as prompt lv 
 
 MCalves'that had heen injeeteil \\ it h corresponding quant it ies of t he 
 unfiltered lymph. 
 
 According to Loefflcr and Froseh. there were two poihlr e\plana- 
 tions of this remarkable result ; either that the filtered lymph held in 
 solution an extraordinary active t\in. or that the specific a.ircnt of 
 the disease was so minute as to pass through the p.i-, iihcr 
 
 which prevents the passage of the smalle-i Un>\\ n bacteria. 
 
 The authors accept the latter explanation, since they were able, 
 in later experiments *, 1 . by means of the filtered lymph. to convey the 
 
 iae through a series of MX animaU. the last of which 
 just as promj)tly after the injection of the filtered lymph a> the iii>t 
 of the series. 
 
 Having, therefore . conclusively determined that the ini< aisrn 
 
 of foot-and-mouth disease of cattle is so extremely minute a 
 readilv through a porcelain filter, it was natural that L(: 
 Froseh should have put forward tbft 
 specific agent of some of the acute infecti 
 animals, such as smallpox, scarlet fever, m 
 mi*rht also belong to this <_ r n>up of ultramicroscopi 
 
 It was for the purpose of ascertaining whether observation con- 
 ducted along the same lines as those ahove mentioned niiixht throw 
 additional light upon the etiology of yellow fever that the folio-, 
 experiments were undertaken. 
 
 Of course it will be thoroughly appreciated that in experimentation 
 on human beings, aside from the ^rave sense -nsihiliu . ai 
 
 times well-ni^h in>uj)nortahle, which the conscientious observer nni-i 
 al\\ays fed. even with the full cn>cnt of the Mihjects to he ex]>eri- 
 mented uj>on, there must be added another factor, vi/, the dilliculty 
 of lindinj; willing and suitable nonimmune individual 
 tation just at the proper and urgent moment. It so happened that 
 on the day of Dr. Carroll's arrival at Habana, Auru>t 11. l ( .n , th 
 patient or the series of seven cases of yellow fever which Dr. ( hn 
 had j)roduce<l hy hites of infected mosquitoes, was taken sick. The 
 fatal termination of three of these cases produced a somewhat panicky 
 feelini: toward experimental yellow fever among the nonimmmi< 
 Habana, which feeling wa s Intensified by the sensational and di-t- 
 statements in one of the local Spanish papers. It was, ihei-efore, 
 extremely difficult in fact, practically impossible to obtain for 
 inoculation purposes person- who could with reasonable certainly l.e 
 regarded as nonimmunes. 
 
 Further, as it was not practical >le to \\ithdraw hlood from any . 
 of yellow fever under treatment in the city of Habana. it heeame 
 necessary to produce cases by means of the hites of infected i 
 rpiitoes Stegom i/ia fasciata accepting such subjects as \\erc willing 
 to submit to this mode of inoculation. In all MX individu.-: 
 posedly nonimniurH's, were bitten l.y mosquitoes, of whom four gave 
 a negative and two a positive result. 
 
YELLOW FEVER. 151 
 
 The following are the negative cases : 
 
 August 14, 1901 S. V., Spaniard, resident of Habana for a few months, was bitten 
 by two insects that had been applied to a yellow fever patient 34 days previously 
 Result negative, although the bites of two mosquitoes from this same lot had already 
 infected an individual, who later died of yellow fever. 
 
 September 5, 1901. J. T., American, was bitten by nine insects that had been ap- 
 plied to a mild case of yellow fever on the second day of the attack, 23 days before. 
 He was again bitten 30 days later by four mosquitoes that had been applied to a mod- 
 erately severe case of experimental yellow fever 11 days before. The result of both 
 inoculations were negative. This man had resided one year in Central America, and 
 we were afterwards informed that he had confessed to a previous attack of the disease. 
 
 September 11, 1901. A. P., Spaniard, was bitten by three insects which 53 days 
 previously had bitten patient with a typical case, on the third day of the attack. 
 These were among a lot of mosquitoes that had already infected three individuals, 
 two of whom died of yellow fever. The result was negative. Five weeks later he 
 received a subcutaneous injection of about one-fourth c. c. of blood drawn from a 
 patient with a mild case of yellow fever, on the second day of illness. Result negative. 
 The previous history of this man was not satisfactory, as he had recently returned from 
 a residence in Mexico. 
 
 September 9, 1901. A. V., Spaniard, was bitten by three mosquitoes that had been 
 applied to a mild case of yellow fever on the second day of the attack, 27 days before. 
 Three weeks later he was again bitten by one mosquito 49 days after it had been ap- 
 plied to a fatal case of yellow fever, on the third day of the attack. The result of 
 both inoculations was negative. 
 
 We give brief sketches of the two positive cases: 
 
 Case I. P. R. C., a Spaniard, had served in the Spanish army in the Philippines. 
 He arrived in Habana from Spain about August 30. 
 
 On September 16, 1901, he was bitten at 4 p. m. by 4 mosquitoes that had previ- 
 ously fed upon cases of yellow fever as follows: One had bitten a patient having a 
 fatal case, on the third day of the disease, 53 days before, and 3 haa bitten a patient 
 having a fatal case, on the second day of illness, 34 days previously. His attack 
 began at 4.30 p. m., September 19, after an incubation period of 72^ hours. At the 
 onset he experienced a slight chill with rigors and loss of appetite. Later in the 
 evening he complained of slight frontal headache and pains in the lumbar region. 
 On the following day the headache and backache were more severe. At 10 a. m. he 
 vomited about 6 drams of slightly greenish fluid containing mucus. On the second 
 day of the attack the gums were swollen, pale, and spongy, and there .was soreness 
 upon deep pressure over the epigastric and hypogastric regions; the face was flushed 
 and the eyeballs were slightly yellow. September 24, fifth day, he was well jaun- 
 diced, epigastric and abdominal soreness were pronounced, and there was nausea 
 with eructations. At this time an unfavorable prognosis was given by two physi- 
 cians of large experience in yellow fever. Happily, with the decline of temperature 
 on the sixth day, the symptoms were much ameliorated and the patient made an un- 
 interrupted recovery. Albumin appeared in the urine on the third day and persisted 
 for 17 days. The microscope showed the presence of bile-stained epithelial and 
 granular casts on the third and subsequent days. 
 
 Early on the second day blood was drawn from the median-basilic vein with all 
 precaution and 10 drops were immediately added to each of four flasks containing 
 200 c. c. of sterile nutritive bouillon. The flasks were kept under observation in the 
 incubator and at room temperature for 14 days without the development of any growth. 
 At the end of that time each flask was agitated and an agar slant was freely inoculated 
 with fibrin and fluid from its contents. These cultures remained sterile 16 days 
 later after being kept four days in the incubator and 12 at room temperature. 
 
 On the second day, blood was drawn for the purpose of obtaining serum for filtration, 
 but owing to an accident to the vacuum pump the experiment had to be abandoned. 
 
 Specimens of the fresh blood were examined for malarial parasites, with negative 
 results, on. the second and fourth days of the attack. (Chart I.) 
 
 Case II. J. M. A., Spaniard, recently landed at Havana, was bitten at 4 p. m. 
 October 9, by 8 mosquitoes that had been applied to a severe case of yellow fever 
 (Case I) on the second day of the disease, 18 days previously. The attack which fol- 
 lowed was mild. According to his own account, he went to bed on the evening of 
 the 12th feeling in perfect health. He awakened about midnight with frontal 
 headache, but had no chill. October 13, 7 a. m., temperature was 102.2 F., pulse 
 92; complained of pain in the head and back; later in the day there was marked 
 photophobia, pain in the region of the kidneys, and slight pains in the lower extremi- 
 
152 
 
 VEB. 
 
 
 i -" rj< 
 
 =-! i j> 
 
 <= mvm\ 
 
YELLOW FEVER. 153 
 
 ties. The eyes were injected moderately and the gums slightly so. On the follow- 
 ing day, October 14, the frontal headache was more severe, there was considerable 
 soreness on pressure over the stomach and abdomen, and he complained of sharp 
 lumbar pain. An examination of the fresh blood proved negative for malarial para- 
 sites. At 4 p. m. blood was drawn from a vein at the bend of the elbow and 10 drops 
 were inoculated into each of 2 flasks containing 200 c. c. of sterile bouillon. One 
 flask remained sterile, the other developed a growth which proved to be a white 
 staphylococcus. 
 
 October 15 the gums were pale, swollen and spongy, their margins distinctly red- 
 dened, and blood could be easily pressed out from beneath the lower gums. 
 
 October 16 there was free oozing of blood from the gums and margin of the tongue. 
 The case pursued a mild course, the temperature falling to normal at 9 p. m. of the 
 fourth day. A trace of albumin was present in the urine passed on the morning of that 
 day, and for a few days following hyalin and granular casts were found. The patient 
 made a speedy recovery. (Chart II.) 
 
 On October 15, 11.30 a. m., at the beginning of the third day of illness, the tempera- 
 ture was 101 F.; 65 c. c. of blood were drawn, with antiseptic precautions, from a vein 
 at the bend of the elbow. This was placed in a sterile test tube and set aside in the 
 refrigerator. At 6 a. m., 5^ hours later, 19 c. c. of a slightly bloodstained serum were 
 pipetted off into another sterile tube. After the addition of an equal quantity of 
 sterilized distilled water the diluted serum was slowly filtered through a new Berke- 
 feld laboratory filter that had been subjected to previous sterilization in an Arnold's 
 sterilizer. In this way 35 c. c. of a slightly bloodstained filtrate were obtained, a part 
 of which was subsequently used for the inoculation of Cases VII, VII, and IX of this 
 report. 
 
 The original level of the blood having been marked upon the tube into which it 
 was drawn, a sufficient quantity of sterilized distilled water was then added to replace 
 the 19 c. c. of serum that had been pipetted off and to make up the original volume of 
 blood. The whole, consisting of clot, remaining serum, and distilled water, was 
 poured into a sterile vessel and whipped up with a sterilized egg beater. The mix- 
 ture, which approximately represented the partially defibrinated blood, was then 
 divided into two parts, one of which was reserved for the inoculation of a control sub- 
 ject (Case III), while the other part was placed in a double water bath previously 
 heated, and exposed to a temperature of 55 C. for 10 minutes. It was then remo ved 
 and immediately cooled in ice water. This cooled material was subsequently used for 
 the injection of Cases IV, V, and VI. 
 
 It will thus be seen that we have at our disposal, for purposes of 
 inoculation, three kinds of materials, derived from the blood in Case 
 II, viz: (a) The unheated and partially defibrinated blood; (&) the 
 partially defibrinated blood which had be.en heated to a temperature 
 of 55 C. for 10 minutes, and (c) the diluted blood serum which had 
 been filtered through a Berkefeld filter. Each of these materials 
 was used for the inoculation of one or more nonimmune individuals 
 with the results that follow herewith. 
 
 (a) THE UNHEATED AND PARTIALLY DEFIBRINATED BLOOD. 
 
 Case IILM.. G. M., Spaniard, arrived at Habana October 4, 1901. At 4 p. m. 
 October 15 he was given a subcutaneous injection of 0.75 c. c. of the unheated and 
 partially defibrinated blood obtained from Case II, 15 J hours previously, which had 
 been kept 5 hours in the refrigerator and 10 hours at room temperature. The earliest 
 symptom, frontal headache, was complained of at 6 p. m., October 20, or at the expi- 
 ration of 5 days and 2 hours after inoculation. Temperature 100.6 F., pulse 80. At 
 3 p. m. of the same day the temperature was 98.4 F., pulse 80. At that time the 
 patient did not complain of any discomfort and there was nothing to indicate that he 
 was about to be taken sick. October 21, 5 p. m., nearly 24 hours From the onset, there 
 was flushing of the face, injection of the eyes and gums, and moderately severe head- 
 *ache; pain in the back, and tenderness on pressure in the epigastric region made the 
 picture complete. On the third day the face was deeply flushed, eyes congested 
 and distinctly yellow. There was slight oozing of blood from the gums. The urine 
 passed at 7.30 p. m. contained a distinct trace of albumin. The case was seen by the 
 Habana Board of Yellow Fever Experts and the diagnosis confirmed. The patient 
 passed through a mild but typical attack, the temperature touching normal on the 
 fifth day. (Chart III.) 
 
154 
 
 
 This case, therefore, serves as a 'vontrol" for the observations 
 \\hich are to follo\\ . >inee it demons rates that the Mood drawn frum 
 the general circulation of case II, at the hednnini: of the thinl day. 
 contained the specific agent of yellow fever, and, in this resnect . con- 
 firms the observations which have heretofore been reported b\ u 
 
 !*-! 
 
 'I 
 
 (I 
 
 I 
 
 (b) THE PARTIALLY DEFIBRINATED BLOOD HEATED FOR 10 MINUTES 
 
 AT 55 C. 
 
 Cote IV. A. C., Spaniard, iioniininune, arrived at Habana, Octobor <;. 1!(> 
 4.35 p. m., October 15. he was given eubcutaneously 1.5 c. c. of th<- partially <1 fil>ri- 
 natea blood which had been Buojected to a temperature of 5. r > < . during K) miniiti . 
 The specimen had been drawn from caoe 1 1, 16 hours before. The result ,f tin- inj ( - 
 .vaa entirely negative, as the subject remained in perfect health during the 10 days 
 following. 
 
YELLOW 
 
 155 
 
 Case V. B. F. M., Spaniard, nonimmune, arrived at Habana, October 6, 1901. 
 At 4.45 p. m., October 15, he received a subcutaneous injection of 1.5 c. c. of the same 
 material that was used in case IV. Result negative. 
 
 Case VI. S. O., Spaniard, nonimmune, arrived at Habana, October 7, 1901. At 
 4.50 p. m., October 15, he was given a subcutaneous injection of 1.5 c. c. of the same 
 material that was used in cases IV and V. No rise of temperature or other symptoms 
 of ill health followed this injection. 
 
 We desire to invite attention to the fact that the four subjects whose 
 protocols have been given above were young Spaniards who arrived 
 at Habana at a time when yellow fever was not present in the city; 
 that they were carried from the quarantine camp, at Triscorma, across 
 the bay, direct to Columbia Barracks, near Quemados, Cuba, where 
 they were kept for seven full days prior to inoculation; and that after 
 
156 YELLOW 11 
 
 inoculation they were kept under <-Ko daily observation for the 
 further j f 10 days, during \\hirh time both temperature and 
 
 pulse were recorded every thin! hour. Since under tlu^e circum- 
 stances each of the three nonimmunes (cases IV, V, and V 1 ) received. 
 without any disturbance to health, double the quantity of heated and 
 partially defibrinated blood that sullued \\hen un heated to cause an 
 attack of yellow fever in case 111. it follows that the specific a*:ent 
 present in "the blood in yellow fever is destroyed, or, at least markedly 
 attenuated, by a temperature of 55 C. maintained for 10 minutes. 
 
 (C) THE DILUTED AND FILTERED SERUM. 
 
 Cote VILP. H. f American soldier, nonimmune, received at 11 a. m. Octob< : 
 1901 , a subcutaneous injection of 3 c. c. of the serum filtrate, representing 1 . "> 
 undiluted serum 101 hours after the blood had been druv. I He rein. 
 
 in good health until 3 p. m. October 19, an interval of four days and fur I 
 his face appeared flushed and his eyes somewhat injected. His temperature at this 
 time was 101 F., his pulse 80. He did not com plain of headache or other pa in 
 this ho'ur his temperature declined, until at 12 o'clock midnight it registered 98 F.. 
 pulse 72. October 20, 9 a. in., temperature 100.8 F.. pulse TS. Face more suffused 
 and slight headache complained of. Fever continued on the 21st, with more marked 
 flushing of the face and injection of the eyes. The height of the primary febrile j 
 yam was reached at 6 p. m. October 21. Remission occurred at 9 a. m. O< t>) 
 when the temperature dropped to 98.8 F., pulse 64. Tin r iM hem 
 
 was followed py a secondary febrile paroxynn of 1- hours' duration. On tli 
 blood was oozing from the lower gums and the eyeballs were tinged with y -11"\\ . 
 Albumin appeared in the urine on the fourth day. The patient was vir-itcd 'by th<> 
 board of experts and the diagnosis of yellow fever confirmed. Examine 
 dried blood for malarial parasites was negative. The patient recovered. (Oi.irt I V. i 
 
 Case VIII. A. W. C., American soldier, nonimmune, was also given at 11.05 a. m. 
 October 15, 1901, a subcutaneous injection of 3 c. c. of the diluted and filtered serum. 
 being the equivalent of 1.5 c. c. of the undiluted serum, 10J hours after the blood had 
 been drawn. He remained in his usual health until about noon, October 1!>. at which 
 time he felt "out of sorts" and ate but little dinner. This was 4 days and 1 hour 
 the injection. During the afternoon he lay down and slept until :* p. m.. when he 
 awoke with a severe headache and backache. His face was flushed. Temperature 
 103.6 F., pulse 102. At this hour his face and eyes were deeply congested, and from 
 this time his symptoms were characteristic of the disease. On the 23d his eye- 
 quite yellow and general jaundice followed later. No albumin was found in this 
 patient's urine. He was seen by the board of experts and his illness pronoiu 
 typical case of yellow fever. Careful examination of the dried blooa for malarial 
 parasites was negative. The patient made a good recovery. (Chart V.) 
 
 Case IX. J. R. B., American, nonimmune, at 2.30 p. m. October 15, 1901, was 
 given a subcutaneous injection of 3 c. c. of the diluted and filtered pcrum. equal to 
 1.5 c. c. of the undiluted serum. Fourteen hours had elapsed since the blood had 
 been drawn from Case 11. 
 
 This injection was followed by no symptoms of physical disturbance, until .". p. m 
 October 19, an interval of four days and a naif hour, when his temperature was 99 
 pulse 92. He complained of headache and flashes of heat, with slight p.iiu b. 
 the shoulders, symptoms which, the subject stated, were a uite unu>ual to him. At ! 
 p. m. temperature 98.4 F., pulse 84. There was n<> further febrile dist urban' 
 the day following the subject was in his usual good health. 
 
 We thus observe that of 3 nonimmune individuals who n < < -ived 
 subcutaneously an injection of filtered blood serum derived from 
 case II of this report, 2 developed an unmistakable attack of yellow 
 fever, after a penod of incubation of 98$ hours and UK) hours re 
 tively, while in 1 case the result must be regarded as negative, 
 
 As already stated, the serum used for these inoculations hud been 
 slowly filtered through a new Berkefeld laboratory filter. As soon 
 as possible thereafter the filter was resterili/ed by steam and thor- 
 oughly tested as to its effectiveness in preventing the passive of 
 bacteria. For this purpose a recent bouillon culture of Staph /, 
 
YELLOW FEVER. 
 
 157 
 
 pyogenes aureus was used, of which 50 c. c. were passed through the 
 niter. The filtrate thus obtained was transferred hi quantities of 
 10 c. c. to each of two flasks con taining 200 c. c. of sterile bouillon, which 
 were incubated at 37 C. for 4 days and thereafter kept at room 
 temperature for 10 days longer, at the end of which tune no growth 
 had occurred. It appears, therefore, that the filter used for the 
 filtration of the blood serum in case II was to be relied upon for 
 the delivery of a bacteria-free filtrate. 
 
 The production of yellow fever by the injection of blood serum 
 that had previously been passed through a filter capable of removing 
 all test of bacteria, is, we think, a matter of extreme interest and 
 importance. The occurrence of the disease under such circumstances, 
 and within the usual period of incubation, might be explained in 
 one of two ways, viz, first, upon the supposition that the serum 
 filtrate contains a toxin of considerable potency; or, secondly, that 
 
 
 \ STOcc \ 
 
 \ J160t.c \ 60Ofc. \_ 
 
 CHAKT IV. Yellow fever, produced by Injection of 1.5 cc. of filtered blood-serum. 
 
 4 hours. 
 
 Incubation, 4 days, 
 
 the specific agent of yellow fever is of such minute size as to pass 
 readily through the pores of a Berkefeld filter. 
 
 In favor of the supposition that in yellow fever an active toxin is 
 present in the blood may be cited the early and well-marked jaun- 
 dice; the free hemorrhage from the mucous membranes of the 
 mouth and stomach, doubtless due to profound changes in capillary 
 vessel walls; the rapid progress of the disease to a fatal termination, 
 the advanced fatty degeneration of the hepatic cells, as well as the 
 marked parenchymatous changes found in the kidneys. f present 
 in the blood this toxin would in all likelihood be found in the serum 
 filtrate obtained from the blood, and if injected in sufficient quantity 
 might induce an attack of yellow fever in a susceptible individual 
 after the usual period of incubation. In this respect it would bear 
 analogy to the production of tetanus in the human being, after the 
 usual period of incubation of this disease by the subcutaneous 
 injection of a very small quantity of tetanus toxin, as reported 
 by Nicolas (7) in 1893, and more recently by Bolton, Fisch, and 
 Walden (8). 
 
15S 
 
 YELLOW FKVK.R. 
 
 Against the view that a toxin is present in tho serum filtrate, we 
 invite attention to the innocuonsness of the nartially deiibrinated 
 blood when heated to 55 (\ for 10 minute-, assnown by the ne^ati\ e 
 results in cases IV, V, and VI. Here the toxin, which mu-t have 
 -ent in i ust the same quantity as in the sen mi lilt rate obtained 
 from this blootf, appears to nave been completely destroyed by the 
 temperature above mentioned. Now, although certain bacteria are 
 dot roved by this temperature, as yet we know of no bacterial l 
 that is rendered inert by such a low decree of heat continued f< 
 short a time. The tetanus toxin, which h, found to be the 
 
 most sensitive (bus far requires, according to Kitasato, a tempera- 
 ture of 60 C. for 20 minutes, or 5r> (\ for U hours, in order to destroy 
 its activity . 
 
 As a further te>t and in order to determine \\hethcr the serum 
 filtrate contained something more participate than a soluble toxin. 
 
 CHART V. Yellow fever, produced by injection of 1.5 cc. of filtered blood serum. Incubation, 4 days, 
 
 1 hour. 
 
 we availed ourselves of the opportunity of oler\ inu r the ell'cct that 
 would follow the transference to a third individual of blood drawn 
 from one of the patients whose attack had been occasioned by the 
 injection of 1.5 c. c. of serum filtrate (case VII). If under i 
 circumstances it would be found that the injection of a -mall quantity 
 of blood was followed by an attack of vellow fever in a thud indi- 
 vidual, the evidence would point in tne strong M manner to the 
 presence of the specific agent of the disease in such blood, since we 
 c an hardly believe that a toxin which had undergone so great a 
 dilution in the body of the second individual would still be capable 
 of producing the disease. 
 
 Cae X. October 22, 1901, 3 p. m., J. M. B., American, nonimmuno, who on 
 October 15, 1901, at 2.30 p. m., had been injected with 1.5 c. c. of serum filtruN- wiih 
 negative result (vide case IX), and who mill <li -in -<l to have his immunity further 
 tested, waff, at the beginning of thin, the eighth day after his former inoculation, given 
 
YELLOW FEVER. 
 
 159 
 
 a subcutaneous injection of 1.5 c. c. of blood drawn from the venous circulation of 
 case VII early in the fourth day of the disease. At the time of inoculation the subjects' 
 condition was quite normal. October 23, 3 p. m., after an incubation period of just 
 24 hours, he complained of frontal and slight basal headache and some pain between 
 the shoulders. His temperature was 99.6 F. and pulse 100. At 6 p. m., temperature 
 100.4, pulse 100. Pain in the back quite severe. At 10.15 p. m., he sufferecfa slight 
 chill. On the following morning the face was flushed and the eyes and gums injected ; 
 there was sharp frontal headache and some photophobia. The height of the primary 
 paroxysm was reached at the end of 23 hours. Remission occurred at 9 a. m., October 
 25, and was followed by a second febrile paroxysm of 45 hours' duration. On the 
 third day, during the secondary fever, the patient presented the typical picture of a 
 mild case of yellow fever; the face was deeply flushed, eyes well injected and slightly 
 yellow; there was sharp headache, and epigastric tenderness and pain in the lower 
 extremities. Heller's test showed albumin in the urine drawn on the fourth day. 
 His fever subsided on the later day and he made a prompt recovery. The case was 
 seen by the board of experts and the diagnosis confirmed. (Chart VI.) 
 
 In considering this individual's attack, his infection must be 
 attributed either to the injection of the serum filtrate derived from 
 case II, in which event the onset of his disease was postponed until the 
 commencement of the ninth day after inoculation, or to the injection 
 
 ?\ 23* 24'* 2 '* 26* 
 
 \AM I JW. \ ~AM. I f.Jf. I AJ I f*f. I A-.M. I f.A 
 
 CHART IV. Yellow fever, produced by injection of 1.5 cc. of blood. Incubation, 24 hours. 
 
 of blood obtained from case VII, after a period of incubation of 24 
 hours. 
 
 In our own experience (10) and that of Guiteras (11) of 22 cases 
 of experimental yellow fever, following the bite of the mosquito, 
 in which the period of incubation was definitely and accurately 
 ascertained, the longest period was 6 days and 1 hour, and the shortest 
 period 2 days and 13 hours. If we take the cases produced by the 
 injection of blood, 7 in number, exclusive of the case under considera- 
 tion, the longest period was 5 days and 2 hours (case III of this 
 report) and the shortest 41 hours. 
 
 In view of these data, we believe we are justified in expressing 
 the opinion that the source of infection in case X must be attributed 
 to the injection of blood drawn from case VII, rather than to the 
 injection of the filtered serum derived from the blood in case II; and 
 further, that the blood in case VII contained the specific agent of 
 yellow fever, which had, therefore, passed through the filter along 
 with the filtrate with which this latter individual had been inoculated. 
 
 The important questions which naturally arise from the foregoing 
 experiments must be left for the future, observations to determine. 
 
160 YELLOW FEVBB. 
 
 BIBLIOGRAPHY. 
 
 (1) The Etiology of yellow Fever An Additional Note. Journal American Medical 
 Association, February 16. 1901. 
 
 (2) Experimental Yellow Fever. Transa the Association of Ameru -an 
 Physicians. Vol. xvi 1901. 
 
 (3) Berichte der Kommisaion eur Erforechung der Maul-und Kkne&wncb 
 dem Inatitut fur Infectionskrankheiten in Berlin. Centnilblatt fur Bicteriologie, 
 Band 9-10. p. 371-391. 
 
 (4) Berichte der Kommission zur Erforechung dor Maul-un.l Klauonscu. !. 
 Centralblatt fur Baetoriologie und Parasitenkunde, Band xxiv, No. 15- . 
 
 (5) Experimental Yellow Fever at the Inoculation Station of the Sanitary Depart 
 ment of Havana, with a view to Producing Immunization. "American Median*. " 
 
 I , No. 21, November 23, 1901. 
 
 (6) "Experimental Yellow Fever." Transactions of the Association of Anx 
 
 1. xvi, 1901. 
 
 (7) Sur un cas de tetanus chez I'homme par inoculation accidentelleprpduitaBoluhK' 
 du bacille de Nicolaier. Comtes Rendus, etc., de la Societe Biologic. Ton 
 1893, pp. 844-46. 
 
 (8) Report of the Commission appointed to investigate the cases of tetanus in St. 
 Louis, following the administration of diphtheria antitoxin. St. Louis Medical 
 
 w, November 23, 1901. 
 
 (9) Zeitschrift fur Hygiene, 1901, Bd. x, S. 283. 
 
 (10) Loc. (it 
 
 (11) Loc. cit. 
 
CHAPTER 8. 
 
 RECENT RESEARCHES CONCERNING THE ETIOLOGY, PROPAGA- 
 TION, AND PREVENTION OF YELLOW FEVER, BY THE TJNITED 
 STATES ARMY COMMISSION (THREE CHARTS). 
 
 By WALTER REED, M. D., Surgeon, United States Army, President of the Commission. 
 [From The Journal of Hygiene, Vol. II, No. 2, April, 1902.] 
 
 The efficient control of the spread of yellow fever is a matter of 
 such vast practical importance, both from the hygienic and com- 
 mercial point of view not only for the countries where this disease 
 prevails as an epidemic, but also for those in which, after importa- 
 tion, it may assume epidemic proportions that it has seemed appro- 
 priate to bring together in this paper a summary of the work thus 
 far accomplished by the United States Army Commission 1 on the 
 island of Cuba, during the years 1900 and 1901, in order that English 
 and Colonial readers who have not, perhaps, had access jto the 
 original contributions published in different American journals, may 
 be able to form an intelligent opinion concerning the permanent value 
 of this work. It will also afford opportunity for recording the more 
 recent confirmatory observations made by others concerning the mode 
 of transmission of yellow fever discovered by the commission, and 
 for calling attention to the results already obtained by the United 
 States Army Medical Department in the suppression or this disease, 
 especially in the city of Habana, through the enforcement of sanitary 
 measures based on these later researches. 
 
 The American commission was organized in May, 1900, and began 
 its investigations during the following month (June), being equipped 
 with suitable laboratory facilities for practical work, both at the 
 military garrison of Columbia Barracks, near Quemados, Cuba, and 
 also in the city of Habana. As yellow fever was already prevailing 
 at the time of our arrival in Cuba suitable material for the scientific 
 study of this disease was immediately available. 
 
 THE ETIOLOGY OF YELLOW FEVER. 
 
 Before giving the results of our investigations it may be well to 
 recall the situation as regards the etiology of yellow fever at that 
 time. Briefly it may be said that the claims of all investigators for 
 the discovery of the specific agent of yellow fever since modern 
 bacteriological methods had come into use had been disproved by 
 the exhaustive observations of__Sternbergjl), published in 1890, ex- 
 cept that made by Sanarelli (2) for a small, motile bacillus isolated 
 by him from the blood drawn during life in 2 of 6 cases of yellow 
 fever, and from the blood and organs after death in 7 of 12 
 cases of this disease (58 per cent), studied at Montevideo and Rio de 
 
 i The members of this commission were Maj. Walter Reed, Surgeon, United States Army, and Drs. 
 James Carroll, A. Agramonte, and the late Dr. Jesse W. Lazear, Contract Surgeons, United States Army. 
 
 79965 S. Doc. 822, 61-3 11 161 
 
162 YELLOW FEVEB. 
 
 Janeiro. Brazil. The results obtained, howm-or. by those who had 
 promptly undertaken to investigate Sanarelli's claim for the specific 
 character of BaciQua icteroides, seemed to show a lack of agreement 
 such as has never been reported, as far as the writer can recall, in 
 connection \\ith the supposed specific cause of any of the other a< -me 
 infections. Thn : d and Woodson ( :>) had, during the 
 
 enidemic of 1V7 in New Orleans, La., isolated a haeillns. claimed by 
 them to he identical with />. tcteroid**, from the venons Mood in 1 
 out of ") eases, and from yellow IV aveTH in 32 nut di 
 
 cases (8'J per cent\ PoHier (4), wurldng in the Same city and during 
 
 the same epid. uld only obtain this bacillus :> time 
 
 51 autopsies, and failed to obtain it at all in cultures made from 
 venous blood during life in H) rases. Again, \\hile Wn-din and 
 Geddings (5), in the city of Habana, were able to eultix ate />'. <<f< / 
 from blood withdrawn frm the lobe of the ear, "not earlier than the 
 third day of the disease" in 13 of 14 cases (92.8 per cent . and to 
 iind it in S.V7 per cent of their necroo-ie-. Agraimmte (ID. stiid\hiL r 
 the disease on the island of Cuba, failed to isolate B. icteroides in a 
 single instance from blood drawn from the lobe of the ear- in 
 or from the blood drawn from a vein at the bend of the elbow in 
 ;>l coses at various stages of the disease. The lattef ob&ctrV&r, ho\\- 
 ever, reported finding this hneillus at autopsy in 1 1 of ;*5 eases 
 per cent). Without goin.tr further into detail, we may .- i the 
 
 residts obtained by Lutz (7) and de Lacerda and Kai n Bra/il. 
 
 and by Matienzo (9) in Mexico, were equally conflicting and nn- 
 
 TV. 
 
 ruder the<e CIK umstances it seemed to the members < -m 
 
 mission of the first importance to give their entire attention to the 
 bacteriological study of the blood of those sick with yellow fever and 
 of the blood and organs of yellow-fever cadavers, having especially in 
 view the isolation of B. icteroides. We were thus able during !une. 
 July, and August to take repeated cultures from the blood during life 
 in IS cases of yellow fever, adopting the usual method employed in 
 withdrawing blood from a vein at the bend of the elbow, and'i 
 ferring the blood at once, in quantities of 0.5 c. c., to each of several 
 tubes containing 10 c. c. of nutritive bouillon which were afterward- 
 incubated at 37 (\ for a period of one week. In7case>. 1 of which 
 were designated as "mild" yellow fever and 3 as "well-mar 1 
 yellow fever, only 1 culture was made from the blood in each 
 case, viz, in 2 cases on the first day; in 1 case on the second 
 day; in 3 cases on the third day; and*m 1 case on the fourth da\ 
 In the remaining 11 cases, diagnosed as "severe" yellow I'. 
 of whom 4 died, more frequent cultures were taken from tl 
 
 varying from 2 to (\ cultures on as many different day- of the 
 disease. In 2 of the fatal cases cultures were made each day from the 
 commencement of the attack and including the day on wliieh d< 
 occurred. 
 
 The negative result of these numerous cultures taken from the 
 blood of ea^e- of yellow fever. a< reirard- the presence of /.'. - 
 
 reported in a "Preliminary note" pre-enied at the meeting 
 
 .'i Public Health Association (10), held in Indiai, Ind.. 
 
 her 22-26, I'.iOO. To the-e is . ;i :m now add r, other 
 cases, or a total of 1M. from which blood culture- have been made 
 during life with negative result-. 
 
YELLOW FEVER. 163 
 
 The importance of this negative finding as regards the growth of 
 any specific bacterium will be better appreciated when it is seen, as I 
 shall soon have occasion to point out, that yeUow fever may be pro- 
 duced in nonimmune human beings by the subcutaneous injection of 
 a small quantity (0.5-2 c. c.) of blood withdrawn from the venous 
 circulation of a patient suffering with this disease. 
 
 In addition to the results above recorded, the careful study of 11 
 autopsies was equally barren as to the presence of any particular 
 micro-organism, although the quantity of material with which our 
 tubes were inoculated was greater than is usually made use of at 
 autopsies. 
 
 In a word, then, the careful bacteriological study which the com- 
 mission had made in cases of yellow fever had given no indications 
 as to the presence of the specific agent of this disease. The same may 
 be said concerning the result of numerous microscopic examinations 
 of fresh and stained specimens of blood which we had in the mean- 
 while studied with a view of finding possibly some intracellular or 
 extracellular body. Apparently no body, bacterial or protozoan, 
 which could be brought into view with a one-twelfth Zeiss immersion 
 objective, was present in the blood of these cases. 
 
 Although displaced from the order in which the following observa- 
 tions were made, it will be best to present, at this time, the results of 
 the experiments which were later carried out by the commission on 
 nonimmune human beings by means of the subcutaneous injection of 
 blood, withdrawn during the active stage of the disease, as these results 
 bear so directly upon the subject which we are now considering, viz, 
 the etiology of yellow fever. 
 
 The only reference that I can find in the literature relative to an 
 attempt to convey yellow fever in this way is cited by Sternberg (11), / 
 who states that at Veracruz, Mexico, in 1887, he saw Dr. Ruis inject 
 into a nonimmune individual a hypodermic syringeful of blood drawn 
 from a case of yellow fever on the eighth day of the disease. The 
 result was negative, as was also the result of two other attempts / 
 related to him by Ruis. 
 
 Our own observations, undertaken for the purpose of ascertaining 
 whether an attack of yellow fever could be induced m a second indi- 
 vidual by the injection of a small quantity of blood, embrace experi- 
 ments made on 12 American soldiers and Spanish immigrants, all 
 nonimmune individuals. 
 
 These observations may be divided into the folio whig classes: 
 
 (1) Injection of the fresh blood taken from a vein at the bend of 
 the elbow. (2) Injection of partially defibrinated blood. (3) Injec- 
 tion of partially defibrinated blood heated for 10 t minutes at 55 C. 
 (4) Injection of blood serum previously diluted with sterilized water 
 and filtered slowly through a Berkefeld laboratory filter. 
 
 The table following (I) gives the results of these several inoculations. 
 
164 
 
 TABLE I. 
 
 So. of 
 CM*. 
 
 Quantity and material used. 
 
 Day of 
 
 diaMM. 
 
 Date of 
 
 :::., -Lit )OB 
 
 Result. 
 
 Date of 
 attack. 
 
 .!! 
 if 
 
 VII 
 
 *$ 
 
 I 
 
 XII 
 
 
 BtMBd . 
 do 
 
 Dec. 26,1000 
 Jan. 4,1901 
 Jan. 8, 1901 
 Jan. 22,1901 
 ' ... M,1901 
 
 . 
 
 ...do 
 ...do 
 ..do 
 
 Negative.. 
 ...do.... 
 
 Jan. 
 11,1801 
 
 19. 1901 
 
 
 f rash blood 
 
 Uti : 
 
 fresh blood... 
 
 ...do 
 
 ittd blood 
 
 ..partially".! 
 for 10 minutes at 65* C. 
 
 S.-MO:IS \, \1I 
 
 
 
 
 
 
 ...do 
 
 1.5 c. r. of fi 
 
 S-iine M No \ 
 
 
 .do.. 
 
 l^'iri.' -i- No \ 
 
 do 
 
 
 
 [2 c c. fresh blood 
 
 
 Oct. 22,1901 
 
 
 By an examination of this table it will be seen that of the sc 
 individuals who received subcutaneoualy the fresh or partially defi- 
 brinated blood in quantities of 0.5-2 c. c., six (85. 7 per rent) de\ 1 
 an attack of yellow fever within the usual period of incubat i< .n of the 
 disease. 
 
 These results are of very great interest as demonstrating that the 
 specific agent of yellow fever is present in the blood, at least during the 
 first, second, and third days of the attack. 
 
 Another important point brought out by these experiments 
 that the blood which conveyed the disease did not contain any 
 terium which would grow on our usual laboratory media. 
 
 In order to establish this fact, as soon as blood had been injected 
 into the nonimmune subject, additional blood was, at onee. withdrawn 
 in considerable quantity and transferred to tubes of nutritive bouillon. 
 In one instance, where 2 c.c. of blood had been drawn into the syringe. 
 0.5 c. c. of this sufficed, when injected, to produce a severe al 
 yellow fever, after 73 hours' incubation, while the remaining 1.5 < . < . 
 transferred immediately to four tubes of bouillon gave no growth. 
 except that from one tube we isolated on the fourth day > 
 coccus pyogenes citreus, found by us to be a common skin-< ontaini- 
 nating organism in Cuba. 
 
 Table If urther shows that the specific agent contained in the hi 
 is destroyed or attenuated by heating the latter at 55 C. for in min- 
 utes, so that the injection of 1.5 c. c. of this heated blood \\ 
 less (cases VII. VIII, and IX), while the injection of 0.75 c. c. of the 
 same blood unneated sufficed to promptly induce an attack of yellow 
 fever in a "control" individual (case VI). 
 
 Of not less interest was the fact brought out by these observat i 
 that yellow fever can be produced by the injection of a small quant ity 
 of bacteria-free serum filtrate, obtained by passing the diluted serum 
 through a Berkefeld laboratory filter (cases X and XI >, and further 
 that the blood of a case of yellow fever, thus produced, when injected 
 into a third nonimmune subject will promptly bring about an attack 
 of this disease (case XII ); thus demon st rat ing t hat the specific a 
 of yellow fever can find its way through the pores of a filter which ordi- 
 narily serves to prevent the passage of all known bacteria. 
 
 I have elsewhere (12) in conjunct ion with one of my collea 
 
 roll) discussed the facts here presented more at length and \\ill 
 limit myself, therefore, to the remark that these experiments app< - ; r 
 
YELLOW FEVER. 165 
 
 to indicate that yellow fever, like the foot-and-mouth disease of 
 cattle, is caused by a micro-organism so minute in size that it might 
 be designated as ultramicroscopic. 
 
 THE PROPAGATION OF YELLOW FEVER. 
 
 Prior to the time at which the foregoing observations were made 
 the commission had already turned its entire attention to the possible 
 solution of the problem of the propagation of yellow fever, being 
 induced thereto, not only by the fruit lessness of the investigations 
 made thus far along bacteriological lines, but, also, by reason of cer- 
 tain facts which seemed to call for a better interpretation than had 
 hitherto been accorded them. 
 
 Without entering into details, I may say that, in the first place, the 
 commission saw, with some surprise, what had so often been noted in 
 the literature, that patients in all stages of yellow fever could be cared 
 for by nonimmune nurses without danger of contracting the disease. 
 The noncontagious character of yellow fever was, therefore, hardly to 
 be questioned. 
 
 In the second place, it had been observed that patients discharged 
 from the wards during early convalescence could be brought into 
 intimate association with nonimmune individuals without thereby 
 establishing fresh foci of the disease. This did not seem to indicate 
 that any specific agent was present in the excreta of the sick. 
 
 Again, it has been noted that in certain cases of this disease no 
 growth had been obtained on the ordinary laboratory media, either 
 by frequent cultures from the blood during life or from the blood 
 and organs after death. 
 
 Further, in the course of an investigation which the commission 
 were able to make during the last week of July, 1900, concerning the 
 origin and spread of a small epidemic of yellow fever that had 
 appeared in a military garrison, numbering about 900 men, at Pinar 
 del Rio, Cuba, they had seen that by reason of the false diagnosis of 
 "pernicious malarial fever" which had been given to these cases no 
 disinfection of bedding or clothing had been carried out; and yet 
 there was no indication that this neglect had contributed in the 
 least to the spread of the disease; nor had any harm come to those 
 nonimmunes who had slept in the beds vacated by the sick, or 
 washed the supposedly infected garments of those who had recovered 
 or died of this disease. 
 
 Putting these various data together, it seemed probable that more 
 progress might be made if attention should be turned to the mode of 
 transmission of yellow fever, especially as our own observations had 
 caused us to seriously doubt the usually accepted belief of the con- 
 veyance of this disease by means of fomites. 
 
 Then, too, the endemic curve of yellow fever in the city of Habana, 
 and its well-known epidemic curve in the United States, appeared to 
 be more intimately associated with and more affected by the rise and 
 fall of the annual temperature curve than was to be seen in any of 
 the acute infections, except malarial fever. The peculiar behavior 
 of this disease (if I may use the expression) in rapidly spreading in 
 certain localities, when introduced, as contrasted with its failure to 
 propagate itself in other places, where the conditions for its increase 
 were apparently just as favorable, seemed to point in the strongest 
 
166 VK1,LO\V KKYKK. 
 
 manner to the necessity for some special agent or intermediate host 
 in the dissemination oi it- >pccific cause. If malarial fever a dis- 
 ease so much affected by temperature condition- n 'quired the 
 agency of a special genus of mosquito for its propagation , as had in 
 recent years oeen so brilliantly worked out oy Ross, Grassi, Bas- 
 tianelli, Bignami, and others, it did not seem unreasonable to sup- 
 pose that yellow fever a disease so plainly controlled by seasonal 
 conditions might also depend on some MK -h iu:ent for its soread. 
 Influenced by this line of reasoning:, the coimni ion l>eran. during 
 the second week of AiiiruM. I'.MM). its observations relative to the 
 propagation of yellow fever by means of the bite of a certain species 
 of mosquito Slegomyia fa-sdata. 
 
 The work alon^ this Une was carried forward so rapidly t hat . within 
 
 30 days, 11 individuals had been bitten by infected Stegom 
 
 of whom two ' developed well-marked attacks of yello\\ lever within 
 
 tlit UMinl period of incubation, and under such circumstances as to 
 
 i\ dy t \. hide in one case any other possible source i ion. 
 
 Appreciating fully the importance of this discovery and in order to 
 exclude all other possible sources of infection hi our future 
 tions. it was now determined to establish a special experimental 
 station where further observations could be made on noiiimmune 
 human beings, both as to tlie propagation of yellow fever by means 
 of the bite of the mosquito as well as by exposure to tl inti- 
 
 mate contact with infected clothing and bedding, and this under the 
 strictest enforcement of military quarantine. With the anpr 
 and assistance of the military governor of the Island of Cuba, this 
 experimental station was ready lor occupancy on November 20, 1900, 
 and was continuously occupied until March 1, 1901. 
 
 As the results obtained at this station have already been published 
 (13) in full elsewhere, I will here only present a brief account, iii 
 the experiments with fomites and afterwards of those made with in- 
 fected mosquitoes. 
 
 ATTEMPTS AT INFECTION BY FOMITES. 
 
 I quote from a paper which the writer presented for the commissi* >n 
 at tlie meeting of the Pan-American Medical Con^rexs.- held in 
 Habana, Cuba, February 4-7, 1901: 
 
 For this purpose there was erected at Camp Lazear a small frame house consisting 
 of one room, 14 by 20 feet, and known as " building No. 1," or the "infectr 
 and bedding building." The cubic capacity of this house was 2,80" it was 
 
 tightly sealed within with "tongued ana grooved" boards, and was w 11 in it. nod on 
 the outside. It faced the south and was provided with two small windows, ea< h _'i; ly 
 34 inches in size. These windows were Doth placed on the south side of thr Imildint:. 
 the purpose being to prevent, as much as possible, any thorough (in illation <>i tin- 
 air within the house. They were closed by permanent wire-screens of 0.5 mm. mesh. 
 In addition a sliding glass sash was provided within and heavy wooden shut i TS with- 
 out; the latt<-r intended to prevent the entrance of sunlight into the building, as it 
 was not deemed desirable ih it tin- dlrinfocting qualities of ninUgfat, dfrad ordflraftd, 
 should at any time be exerted on the articles of clothing contain* ! within tl-.i - 
 Entrance wan effected through a small vestibule, 3 by 5 feet, also placed <>n th< ;.:h< rn 
 side of the house. This vestibule was protected without by a solid door ami 
 <li\i<ll in its middle by a wire-screen door, swung on spring hinges. Th<- inn< r 
 entrance was also closed by a second wire-screen door. In this way the passage of 
 
 > One of UMM OMMt was that of Dr. James Carroll, Contract Surgeon, U. 8. A., a member of the 
 
YELLOW FEVER. 167 
 
 mosquitoes into this room was effectually excluded. During the day and until after 
 sunset the house was kept securely closed, while by means of a suitable heating 
 apparatus the temperature was raised to 92-95 F. Precaution was taken at the same 
 time to maintain a sufficient humidity of the atmosphere. The average temperature 
 of this house was thus kept up at 76.2 F. for a period of sixty-three days. 
 
 November 30. 1900, the building now being ready for occupancy, three large boxes 
 filled with sheets, pillowcases, blankets, etc., contaminated by contact with cases of 
 yellow fever and their discharges were received and placed therein. The majority 
 of the articles had been taken from the beds of patients sick with yellow fever at Las 
 Animas Hospital, Habana, or at Columbia Barracks. Many of them had been pur- 
 posely soiled with a liberal quantity of black vomit, urine, and fecal matter. A dirty 
 "comfortable " and a much-soiled pair of blankets, removed from the bed of a patient 
 sick with yellow fever in the town of Quemados were contained in one of these boxes. 
 The same day, at 6 p. m., Dr. R. P. Cooke, acting assistant surgeon, United States 
 Army, and two privates of the Hospital Corps, all nonimmune young Americans, 
 entered this building and deliberately unpacked these boxes, which had been tightly 
 closed and locked for a period of two weeks. They were careful at the same time to 
 give each article a thorough handling and shaking, in order to disseminate through the 
 air of the room the specific agent of yellow fever, if contained in these fomites. These 
 soiled sheets, pillowcases, and blankets were used in preparing the beds in which the 
 members of the Hospital Corps slept. Various soiled articles were hung around the 
 room and placed about the bed occupied by Dr. Cooke. 
 
 1 From this date until December 19, 1900, a period of 20 days, this room was occupied 
 each night by these three nonimmunes. Each morning the various soiled articles 
 were carefully repacked in the aforesaid boxes, and at night again unpacked and dis- 
 tributed about the room. During the day the residents of this house were permitted 
 to occupy a tent pitched in the immediate vicinity, but were kept in strict quarantine. 
 * * * * * * * 
 
 December 19 these three nonimmunes were placed in quarantine for five days and 
 then given the liberty of the camp. All had remained in perfect health, notwith- 
 standing their stay of 20 nights amid such unwholesome surroundings. 
 
 During the week December 20-27 the following articles were also placed in this 
 house, viz, pajamas suit, 1; undershirts, 2; nightshirts, 4; pillow slips, 4; sheets, 6; 
 blankets, 5; pillows, 2; mattress, 1. These articles had been removed from the per- 
 sons and beds of four patients sick with yellow fever and were very much soiled, as 
 any change of clothing or bed linen during their attacks had been purposely avoided, 
 the object being to obtain articles as thoroughly contaminated as possible. 
 
 From December 21, 1900, till January 10, 1901, this building was again occupied 
 by two nonimmune young Americans under the same conditions as the preceding 
 occupants, except that these men slept every night in the very garments worn by 
 yellow fever patients throughout their entire attacks, besides making use exclusively 
 of their much-soiled pillow slips, sheets, and blankets. At the end of 21 nights of 
 such intimate contact with these fomites, they also went into quarantine, from which 
 they were released five days later in perfect health. 
 
 From January 11 till January 31, a period of 20 days, ''building No. 1" continued 
 to be occupied by two other nonimmune Americans, who, like those who preceded 
 them, have slept every night in the beds formerly occupied by yellow fever patients, 
 and in the nightshirts used by these patients throughout the attack without change. 
 In addition, during the last 14 nights of their occupancy of this house they had slept 
 each night with their pillows covered with towels that had been thoroughly soiled 
 with the blood drawn from both the general and capillary circulation on the first day 
 of the disease, in the case of a well-marked attack of yellow fever. Notwithstanding 
 this trying ordeal these men have continued to remain in perfect health. 
 
 The attempt which we have therefore made to infect "building No. 1 " and its seven 
 nonimmune occupants during a period of 63 nights has proved an absolute failure. 
 
 INFECTION BY MOSQUITOES. 
 
 While the experiments with fomites were being carried out in 
 " Building No. 1," certain nonimmune individuals wfro were lodged 
 in tents, in a separate part of the camp, were being subjected, with 
 their full consent, to the bites of mosquitoes which had previously fed 
 on the blood of cases of yellow fever occurring in the city of Havana. 
 Thus during the period from December 5, 1900, to February 7, 1901, 
 we had subjected to this method of infection 12 nonimmune subjects, 
 
HiS 
 
 
 who had previously passed their full record of quarantine in this 
 camp. Of these 10, or 83.3 per cent, experienced attack- of yellow 
 fever and always within the period of incubation of this di 
 
 The following Table II gives the necessary data concerning these 
 observations : 
 
 TABLE 11 
 
 \ l' 
 
 Days in 
 
 Inocul 
 
 ilion. 
 
 Mi-tho.t nf 
 
 i i 
 
 ! i r :. ! 
 
 .if tnea 
 
 
 Orte 
 
 
 cms*. 
 
 i sr 
 
 BMT, 
 
 lut.'. 
 
 InoculaUon. 
 
 tattoo 
 
 :n 
 
 boon. 
 
 Result. 
 
 mot* 
 
 cxvunviuv 
 
 I 
 
 n 
 
 16 
 
 o 
 
 2p.m... 
 4 p. in 
 
 Dec. 5, 1900 
 Dec. 8, 1900 
 
 Mosquito.... 
 
 m 
 
 137 
 
 Positive 
 
 .do 
 
 ni 
 
 I.v. Vl'.i 
 
 m 
 1 
 
 VI 
 
 19 
 21 
 82 
 31 
 
 10JOa.m 
 4.30 p. m 
 12m. 
 10 a. in 
 
 Dte. ,1900 
 Dec. 11,1930 
 Dec. 21.1900 
 Jan. 8,1901 
 
 do 
 
 do 
 
 : 
 
 .do... 
 
 831 
 
 S l 
 
 do 
 do 
 do 
 
 11 
 
 VI 
 
 Dec, I.M'.N 
 Deo. i.vi-Mi 
 Deo. 26,1900 
 
 VII 
 VIII 
 
 22 
 
 09 
 
 8.30 p. m 
 
 Dte. 10,1900 
 
 Jan. 19. 1901 
 
 do 
 .do 
 
 $ 
 
 Positive 
 .do... 
 
 VII 
 Mil 
 
 Jan. 3.1901 
 Jan. 23 1901 
 
 
 
 \u 
 
 74 
 6 
 78 
 25 
 
 10.30 a. m 
 9.30 a.m 
 lla.m 
 2 p. m 
 
 Jan, 26,1901 
 
 Jan. 31.1901 
 
 K.'h. ... 1-..H 
 Feb. 7, 1901 
 
 do 
 do 
 do 
 . ..do 
 
 " 
 
 70 
 
 Negative. . . . 
 ive 
 
 .do 
 
 XII 
 
 Feb. 3, 1901 
 
 
 
 
 
 
 
 
 
 
 The positive results obtained, therefore, by this mode of infection 
 stand in striking contrast to the negative experiments made with 
 fomites. Indeed, cases VIII and XI of Table II had each >lept _'l 
 nights in the garments of yellow fever patients while occupan 
 '' building No. 1." As they had remained in perfect health at Camp 
 La /ear for yet 30 days longer, they were at the expiration of this 
 time bitten by infected mosquitoes solely for the purpose of testing 
 their immunity and with the result that an attack of yellow fever 
 promptly followed in each case. 
 
 It should be borne in mind, also; that of the nonimmune re-idem s 
 at Camp Lazear, while all lived under the same hygienic condition^. 
 only those individuals developed yellow fever who were purp 
 bitten by contaminated mosquitoes, or injected with the blood of 
 those sick with this disease. Moreover, the precision with which the 
 infection of the individual followed the bite of the mosquit< 
 nothing to be desired hi order to fulfil the requirements of a s< lentil ie 
 experiment. 
 
 Case V of Table II is of especial interest, when taken in connection 
 with the failure to induce the disease by contact with fomites. 
 
 This individual, having been quarantined for 32 days at Cami> 
 Lazear, volunteered to enter a newly erected building in which 
 15 contaminated mosquitoes had just been freed. His lirM \ rit 
 was at noon, December 21, 1900, and the length of his stay 30 min- 
 utes. At 4.30 p. m. the same day he again entered this building and 
 remained 20 minutes. The following day at 4.30 p. m. he for the 
 third time visited this room and remained 20 minutes. During 
 each of these visits he was bitten by mosquitoes. He did not enter 
 the building again, nor was he exposed to any other source of i; 
 . Nevertheless at the expiration of 3 days and 2:\ hour 
 at 6 a. m. December 25, 1900, he was suddenly seized with an attack 
 of yellow fever, which proved to be severe in char. Th.it the 
 
 infection was occasioned by the bites of contaminated mosqui; 
 plainly shown by the immunity from the disease enjoyed l.y two 
 
YELLOW FEVER. 169 
 
 nonimmune "controls," who, protected only by a wire-screen parti- 
 tion, had been present at each of the subject's visits and who under 
 the same conditions of security against the bites of the infected mos- 
 quitoes continued to sleep in and breathe the com mom atmosphere 
 of this room for yet 18 nights. 
 
 To the positive cases contained in Table II, which were produced at 
 Camp) Lazear, we are now able to add 4 other cases of yellow fever 
 occasioned by the bites of infected mosquitoes, thus making a total of 
 14 cases, in each of which happily recovery followed. 
 
 A very important point brought out by these observations is that 
 an interval of about 12 days or more after contamination appears to 
 be necessary before the infected Stegomyia is capable of conveying 
 the disease to a susceptible individual. Repeated experiments made 
 with insects which had bitten yellow fever patients 2 to 10 days pre- 
 viously were always negative, although these same insects were 
 proven capable of conveying the disease after having been kept until 
 17 to 24 days had elapsed. Our observations (14) further demonstrate 
 that mosquitoes that have been kept for periods varying from 39 to 
 57 days after contamination are still capable of conveying the disease, 
 and further that infected Stegomyia may survive for a period of at 
 least 71 days. This will explain how the contagion of yellow fever 
 may cling to a building, although it has been vacated for a period of 
 two or more months. 
 
 Bearing in mind that the observations made by means of blood 
 injections (Table I) were only undertaken after we had succeeded in 
 demonstrating that the disease could be conveyed by the bites of 
 infected Stegomyia, it will be seen that our study of the method of 
 propagation of yellow fever, at Camp Lazear, sufficed to prove very 
 definitely that, while the natural mode of transmission of this disease 
 is through the bites of infected mosquitoes, yellow fever may also be 
 conveyed, like malarial fever, by the injection of a small quantity of 
 blood taken from the veins of an individual suffering with this disease. 
 
 Per contra, our observations show that, notwithstanding the com- 
 mon belief in this mode of transmission, yellow fever can not be 
 induced in the nonimmune individual even by the most intimate con- 
 tact with contaminated articles of clothing and bedding. 
 
 Although the investigations made at Camp Lazear were only con- 
 cluded one year ago, already confirmatory evidence of the strongest 
 character has been furnished in a series of experiments carried out by 
 Guiteras (15) at the inoculation station of the sanitary department 
 of Habana. 
 
 I may be pardoned for quoting the paragraph with which Guiteras 
 begins his contribution. He says : ' l The favorable results obtained by 
 the United States Army commission in their experiments with yellow 
 fever, the continued series of mild cases resulting from these experi- 
 ments without a death, suggested very naturally the continuation of 
 their work on a larger scale ; not with a view to control or confirm the 
 conclusions of the commission, for anyone who had followed their 
 work with unprejudiced attention must have concluded that their 
 solution of the problem of the etiology of yellow fever was final; but 
 rather in the hope of propagating the disease in a controllable form, 
 and securing amongst the recently arrived immigrants immuniza- 
 tion, with the minimum amount of danger to themselves and the 
 community." 
 
170 
 
 YELLOW FEVER. 
 
 Of a total of 4'J individual- inoculated by (iuiteras _>,"> were rejected 
 by him by D .\\i\ been bitten by in^eeis that had been 
 
 apohed to cases of fever about which the diai: -in doubt. The 
 
 following table, therefore, only includes 17 per-ons \\lio were bitten 
 by Stegomyva that had previously foil on unmistakable ca><^ ((' \ ellow 
 fever at imT\aU of l l -re being applied to the non- 
 
 immune subject. 
 
 TABLE 111 
 
 No. 
 of 
 
 DftU of (nor- 
 ulaiion. 
 
 Uode of inoculation. 
 
 Result. 
 
 
 
 Feb. 23.1901 
 Aug. 4. 1901 
 
 Mosauito... 
 
 Positive. 
 
 3 days, 10 hours. 
 
 
 do 
 Aug. 7.1901 
 A.;* ^ LOOJ 
 do 
 
 do. 
 do 
 do. 
 
 do 
 
 i 
 .. .do 
 
 -.5 hours. 
 
 i '1 i\ > '.', hours 
 
 
 Aug. 
 
 \ut '. 'r'l 
 
 ..'.do.... 
 
 Posit 
 
 
 
 Aug 10.1901 
 
 do 
 
 
 
 10 
 11 
 
 ...do. 
 do 
 
 do 
 do 
 
 .do 
 
 
 
 \Ug 13 1901 
 
 do 
 
 Positive 
 
 3 day* 19 hours 
 
 13 
 
 do 
 
 do 
 
 Negative 
 
 
 14 
 
 \ug 14 1901 
 
 do 
 
 
 
 15 
 
 do. 
 
 do 
 
 do 
 
 
 16 
 
 Aug. 22.1901 
 Aug. 24,1901 
 
 do 
 do.... 
 
 
 Sdaya. 
 
 A more complete confirmation of the results ol>tain<'d h\ the 
 American commission could not be furnished than the data eontained 
 in the foregoing table, since they show that of 17 individuals who 
 were bitten by infected Stegoniyia fasciata , 8 (47 per cent ) devrl 
 the disease. Most unfortunately, in three of these cas< rave 
 
 symptoms ensued, such as Mark vomit and suppression of the urine, 
 which eventuated in the death of the patients. I may add that in the 
 hands of Guiteras fomites failed to exert any effect on nonimmun 
 
 Whether other species of mosquitoes than Stegomyia are capable <>f 
 conveying the parasite of yellow fever has not as yet been determined 
 by the commission; nor have we been able to ascertain whether the 
 parasite passes from the mother insect to daughter Insects* The 
 experiments which we have thus far been able to make for the pin 
 of determining these important points, although negative, have hern 
 too few in number to warrant any definite expression of opinion. 
 
 THE PREVENTION OF YELLOW FEVER. 
 
 The definite determination of the way in which yellow fever is 
 transmitted from the sick to the well furnishes a solution at h: 
 that much vexed problem of how to prevent the spread of the di- 
 Even in the absence of more definite kmmled^e eonrernii rific 
 
 agent knowledge greatly to be de>h-cd from the scientific stand- 
 point we are now able, as sanitarians, to direct our efforts alon- 
 tain well-defined lines, with a fcelim: :ity heretofore unki> 
 
 From the point of view of prevention the situation may be briefly 
 summed up in the following conclusion, which v. .-nted by the 
 
 American Army commission to the Pan-American ( ..f moo. 1 
 
 /.- eft, 
 
YELLOW FEVER. 171 
 
 viz, "The spread of yellow fever can be most effectually controlled by 
 measures directed to the destruction of mosquitoes and the protection 
 of the sick against the bites of these insects." 
 
 This conclusion was the logical outcome of the observations that 
 had been made by the commission at its experimental station near 
 Quemados, Cuba'. 
 
 The importance of the discovery that yellow fever is transmitted by 
 the bite of a certain species of mosquito did not fail to attract the 
 prompt attention of the military governor of the island of Cuba, 
 himself a physician and formerly a distinguished member of the 
 Medical Department of the United States Army. By his direction 
 the theory was at once subjected to a practical test in the city of 
 Habana, in which city yellow fever had not failed to make its yearly 
 appearance during the past 140 years. 
 
 Under the efficient management of the chief sanitary officer, 
 Surg. Maj. Wm. C. Gprgas, United States Army, the sanitary regula- 
 tions were so far modified as to require that every patient having yel- 
 low fever should not only be quarantined, but that his room should be 
 promptly protected with wire screens, so as to prevent the possibility 
 of mosquitoes becoming infected by sucking the blood of the patient. 
 As a second important measure, a systematic destruction of all mos- 
 quitoes in other rooms of the patient's house, as well as in adjoining 
 houses, was at once begun, the fumes of pyreihrum being relied upon 
 to stupify the insects, after which they were carefully swept up and 
 burned. In other words, Surg. Maj. Gorgas relying upon the well- 
 known slow progress of yellow fever sought to destroy all mosquitoes, 
 infected or noninfectecl, within a given radius of each case, while at the 
 same time he effectually excluded all mosquitoes from access to the 
 sick. If a secondary case occurred, the same hygienic measures 
 were vigorously enforced along the lines above indicated. 
 
 As an illustration of what has been accomplished by these newer 
 sanitary regulations, I may state that counting from the date when 
 they were put into force viz, February 15, 1901 Habana was freed 
 from yellow fever within 90 days; so that from May 7 to July 1 
 a period of 54 days no cases occurred. Notwithstanding the fact 
 that on the latter date, and during the months of July, August, and 
 September, the disease was repeatedly reintroduced into Habana 
 from an inland town, no difficulty was encountered in promptly 
 stamping it put by the same measures of sanitation intelligently 
 applied both in the city of Habana as well as in the town of Santiago 
 de las Vegas, whence the disease was being brought into Havana. 
 
 As a further illustration of the remarkable sanitary victory accom- 
 plished over a disease whose progress we had heretofore been powerless 
 to arrest, I will close this paper by inviting the reader's attention, first 
 to the accompanying Chart I, which shows the average monthly 
 mortality from yellow fever in Habana for the 20 years 1880-1899, 
 inclusive, and also the mortality by month for the years 1900 and 
 1901. I will then ask him to examine Chart II, which shows the 
 progress of yellow fever in Habana during the epidemic year, ending 
 March 1, 1901, when the sanitary authorities were putting forth every 
 effort known at that time to sanitary science in order to control the 
 march of the disease; and when he has satisfied himself that no effect 
 whatever was produced upon the epidemic of that year, I will invite 
 his attention to Chart III, which shows the occurrence of this disease 
 
172 
 
 YELLOW KKVER. 
 (11 MIT I. 
 
 Showing monthly mortality from yellowfever in the city of Havana, for the twenty years, 
 
 1900-1901. 
 
 Dec. 
 
 Oct. 
 
 - June 
 
 My- 
 
 Jany. 
 
YELLOW FEVER. 
 
 173 
 
 CHART II. 
 
 Cases and deaths from yellow fever in the city of Havana, for the epidemic year March 1 
 1900, to March 1, 1901 (by month}. 
 
 CHART III. 
 
 Cases and deaths from yellow fever in the city of Havana, for the epidemic year, March 1, 
 1901, to March 1, 1902 (by month). 
 
 1901 
 ~T 
 
 J9M 
 
 J&nttv g 
 
 SO 
 
 Cases. 
 
174 YK.I.I.OU 
 
 in Habana for the epidemic year March 1. l'M)i, to March 1.1 
 during which year Yellow fever was fought on the theory that the 
 specific agent of this disease is transmitted solely hy means of the 
 bites of infected mosquitoes. By carefully comparing the figures 
 both as to deaths and cases in these two charts, and recalling that 
 
 between the \ears 1853 and 1900 there have hern recorded in the city 
 
 iubana 3">.t.YJ d in \ellow fever, he \\ill then he ahle to 
 
 more clearly appreciate the \alue of the work mvomplishnl hy the 
 
 American Army commission. 
 
 BIBUOGRAI IM 
 
 (1) Report on th Kii.. !..-:> am) rr-\.'ini.-i 
 
 (2) LA Fiebre Amarilla. ( ..nf. r. n. ia <lada en la Universidad de Mmit.-vi.i. 
 10Juniol897. Reprint 
 
 (3) Bacteriological Study in th<- Kticlc-ry ..f y,.||,,\v I-'.-VT. \,-n- York M 
 Journal, Jan. 28, 1899 pp. 109 111 
 
 (4) Summary of Pathologic and Bacteriologie Work, at Isolation, N- 
 nal of the American Medical Association, April 16, 1898, pp. 884-888. 
 
 (5) Tin- Ktiolo-y <>f Y<-llo\v Fcv.-r. Al.stractof Report, <fcr. N. Y. Med. .Innnuil. 
 August 26, 1899, pp. 299-302. 
 
 (6) Report upon Bacteriological Investigations in Yellow Pew, Hi. M 
 News, N. Y., February 10 and 17, 1900. 
 
 (7) KevistacT Igiene e Sanita I'tiMim. \i. No. IH. July, 1900, pj' 
 
 (8) La Ba< illc Icterolde M Sa T-xiin . Archives de Medicine Experimental* <(:< 
 1899, pp. 378-398. 
 
 (9) Nota para Servir al estudio bacteriologico de la Fiebre Amarilla. Gaceta Medico 
 de Mexico, xxxvi, 1899, pp. 218-230. 
 
 (10) The Etiology of Yellow Fever. A Preliminary Note. The Philadelphia Med. 
 Journal. ()<-i.,l.-r 'J7. 1900. 
 
 (11) Yellow Fever. Buck's Reference Hand-book of the Medical Sciences, Vol. vni. 
 1889, p. 48. 
 
 (12) The Etiology of Yellow Fever. A Supplementary Note. American Mcd 
 Vat in. No. 8, February 22, 1902, pp. 301-305. 
 
 (13) The Etiology of Yellow Fever. An Additional Note. Jo 
 Medical Association, February 16, 1901. 
 
 (14) Experimental Yellow Fever. Transactions of the Association of American 
 Physicians, Vol. xvi, 1901. 
 
 (15) Experimental Yellow Fever at the Inoculation Station of tin- Sanitary 1 Apart- 
 ment of Havana. American Medicine. Vol. n, No. 21, 1901, pp. 809-817. 
 
OR. JAMES CARROLL. 
 
PART III THE PUBLICATIONS OF JAMES CARROLL, ASSISTANT SUR- 
 GEON, UNITED STATES ARMY, IN REGARD TO YELLOW FEVER, 
 
 [Published after the death of Maj. Walter Reed.] 
 
 CHAPTER 1. 
 THE TRANSMISSION OF YELLOW FEVER. 1 
 
 By JAMES CAEROLL, M. D., 
 Assistant Surgeon, United States Army. 
 
 [Read at the forty-fourth session of the American Medical Association, in the section on practice of medi- 
 cine, and approved for publication by the executive committee: Drs. J. M. Anders, Frank A Jones and 
 W. S. Thayer.] 
 
 Several American observers have noted that during the yellow 
 fever outbreaks mosquitoes were very numerous, among them 
 Rush(l),at Philadelphia in 1797; Dr. Weightman(2), of the United 
 States Army, at St. Augustine, Fla., in 1839; Dr. Wood (3), at Center- 
 ville, Miss., in 1853. Dr. E. H. Barton (3) states "that at Clinton, 
 La., in 1853, mosquitoes were uncommonly numerous night and day." 
 At Trinity, La., in the same year, when sawdust was used to fill 
 up low places in the streets, the disease was not propagated, though 
 many cases were brought there and no precautions were used (3). 
 It is hardly necessary to note what the effect of this obliteration of 
 puddles would be on the development of mosquitoes. Dr. Beyren- 
 heidt(3), of Biloxi, Miss., in reporting a severe epidemic at that place 
 in 1853, during which 533 cases and 111 deaths occurred in a popula- 
 tion of 5,520, makes the interesting statement that " mosquitoes 
 and fleas were very abundant." Dr. Bennett Dowler strongly 
 urged drainage of the city of New Orleans, and spoke of the city and 
 its environs as " mosquito lands "(4). La Roche (5) states that in 
 1793, during the epidemic in Philadelphia, "the narrow streets and 
 alleys near the wharves, as, indeed, in many other parts, were in a 
 foul state, and the gutters almost everywhere sadly neglected." In 
 1794 Rush and others ascribed the fever to exhalations from wharves, 
 neglected gutters, and stagnant ponds(5). In 1797, during another 
 outbreak in Philadelphia, the condition was practically the same; 
 the Academy of Medicine called the attention of the governor to 
 the putrid exhalations from the gutters, streets, ponds, and marshy 
 grounds of the neighborhood of the city (5). While high temperature, 
 low altitude, and the presence of standing water are the conditions 
 most favorable to the development of a yellow fever epidemic, there 
 are numerous instances on record where the disease after introduc- 
 tion spread from house to house throughout the town in places 
 where the general conditions of sanitation and drainage were good. 
 This is now explained by the habits of the mosquito (Stegomyia 
 fasciata), which Dreeds in standing water, in houses as well as out of 
 
 i Journal of the American Medical Association, May 23, 1903. 
 
 175 
 
176 YELLOW 
 
 doors. As a general rule, in ports where yellow fever epidemics first 
 appear, the conditions arc known to be favorable for the dovelop- 
 incnt of enormous numbers of mosquitoes. 
 
 A very interesting observation \\as mad.' in ix:w in South Africa 
 by William Ferguson. then a surgeon in the South African corps, in 
 regard to the extension of yellow fever from Sierra when 1 it 
 
 had been brought on vessels from tho West Indies) to (iambia. 
 Goree, and Ascension, the subsequent ports of arrival of some of 
 these infected vessels. After mentioning an unusually heavy accu- 
 mulation of mud and filth in a pit at Ascension, which was -aid to 
 have been the cause of the fever oceurring after an unusually heavy 
 fall of rain, he makes the following statement: 
 
 (6) It will be observed that at AN <>c. and at Gambia a hrcc 
 
 or four weeks always elapsed betwixt the landing of the sick ami tin- j.i.irniie ..ui- 
 breaking of the disease among the Dopulation, a degree of uniformity worthy of remark 
 \\ lu-ther the conclusions at wni<h I have arrived (mat the disease was earn 
 places on infected vessels) be mistaken or not. 
 
 These outbreaks were accompanied by black vomit and 
 undoubtedly yellow fever of imported origin. 
 
 .lust 60 years later Carter (7) made a similar observation in the 
 United States, shortening the period slightly and givinir cases and 
 data. In a later paper (8) he de-senates the interval hot ween pri- 
 mary and secondary cases the period of "extrinsic incubation." 
 
 The known facts regarding tne apparent noncontagiousness of the 
 disease, the peculiar manner in winch it has been seen to pass from 
 one house to another without intercommunication of the inhahh , 
 and the numerous points of resemblance between yellow lever and 
 malaria, led us to expect results from mosquito inoculations in \ el low 
 fever. After satisfying ourselves that B. icteroides (Sanardli 
 not to be considered, Drs. Reed, Lazear, and myself, in consultation. 
 decided that the mosquito theory had many facts to support ii 
 could be promptly decided one way or the other. This lead- iu 
 consideration of the mosquito theory of Finlay. 
 
 At the session of the Royal Academy of Sciences, Habana. Ai: 
 14, 1881, Finlay first gave to the world his memorable theory of the 
 transmission of yellow fever by the mosquito, and reported 
 experiments, which are included in the accompanying table, compris- 
 ing all of Finlay's and Delgado's positive cases piiblisned in 1 v 1 
 
 Finlay believed (10) that the transfer of the specific agent of the 
 disease from patient to nonimmune was effected mechanically by t he 
 insect's proboscis (14) and that the infection would be convc 
 immediately if the insect chanced to bite a susceptible person a few 
 moments alter feeding on a patient in the proper stage of the dis- 
 ease. (11) He also thought that the graver forms of yellow fever 
 might be produced by the bite of CuLex pungens, because the i 
 ingested a larger amount of blood than stegomyia, and consequently 
 a greater quantity of the virus would be retained on its piob 
 (stylet). (11) He ventured the opinion that yellow foyer Wi 
 of eruptive fever, and that the seat of the eruption was the on dot ! 
 lining of the blood voxels, and that the mosquito nicked up t he inocii-- 
 lable material f rom the interior of the blood vessef> on its biting appa- 
 ratus and transferred the same to the interior of the vessels of the per- 
 son subsequently bitten. 
 
YELLOW FEVER. 
 
 177 
 
 g . ESS 
 fLd -^2 
 
 
 d 
 
 
 
 'S 5 5 "8 T3 rrj <3 ^> O IH 
 
 i K fiifi 1 
 
 
 SSft we H w w 5 
 
 er 
 k. 
 
 o o o 
 
 z; 
 
 a 
 
 IN o oo 
 
 < JH - ~ 
 -^ : "S 03 ^ ^ 
 2 ^^ ^ ^ 
 
 CO CC(N (M 
 
 when the 
 was bitte 
 
 IS < ^ 
 
 Date of contam 
 of mosquit 
 
 3333 33 
 
 79965 S. Doc. 822, 61- 
 
178 VEB. 
 
 In a later paper he assumes that the picking up of those germs by tho 
 proboscis of the moMjuito is selective, because there i^ nothing in prove 
 that other inoculable diseases have I D BO ( i an-mitted. From 
 
 four culture experiment*-, in each of which the head and the pro- 
 boscis of a mosquito W6I6 dropped into a bouillon tube, he infers that 
 the head and the pro)..-. -U ot t: .uito possess bactericidal 
 
 properties for ordinary bacteria and fungi \\ith the exception 
 08, \vliich was subset | uen tly 1 1- > claimed to be the specific a 
 of the disease. (!-".) The sting of the mosmiito b suggested as the 
 "intermediate host" necessary for some pnase of development of 
 disease germs. (14) 
 
 As late as 1899 Kinlay mentions the isolation of the tetracoccus from 
 culture media into which the heads and nroboscides of contamin 
 mosquitoes had boon dropped, as one of t ne three result- of his e \peii- 
 ments on yellow fever mosquitoes. 
 
 In a paper (13) published in 1895 he announced some very inte 
 ing results obtained with the "tetracoccus." A number of rabbits 
 were inoculated in traperi tone ally with cultures in bouillon; one of 
 these cultures had been obtained'from the head and the proboscis 
 mosquito bv placing them in a tube of bouillon five days after the 
 insect had bitten a yellow-fever patient; the others came from the 
 finger blood and milk of yellow-fever patients. All of the rabbits 
 died; some of them showed infarcts of the kidneys, lungs, and liver. 
 A rabbit obtained from the count rv was placed in the stable where 
 some of the other rabbits had been kept, and at the end of eight days 
 it was found dead. The tetracoccus was obtained from its he; 
 blood. 
 
 Eleven days after the rabbits had been removed from the house 
 (the stable is usually a part of the house in Habana) a Spanish wet 
 nurse came to spend some time there and on the third day following 
 her arrival she was attacked with yellow fever. Mosquitoes had been 
 unusually abundant in the house during the whole time the inocu- 
 lated rabbits had been kept in it, and we are asked to keep this in 
 mind in view of the possible transmission of the disease from animals 
 to man. We are told that the blood from the finger of this woman on 
 the third day of her illness gave the "pale yellow tetra< and 
 
 the milk from her breast gave a "white tetracoccus," which pi 
 fatal to a rabbit in 15 days. (13) 
 
 While reading the accounts of these experiments one is coiiMantly 
 reminded of the pathogenic staphylococci. It is strongly - 
 (13) that the rabbits died of yellow fever, and it is asserted that the 
 experiments justified the assumption that the tetracoccus wa> the 
 "specific germ of yellow fever." 
 
 The statement is also made in this paper that of 100 presumably 
 susceptible person- who had received the mosquito inoculation during 
 the 14 years previous, only 3 had subsequently died of vellow fever. 
 (13) 
 
 I have been unable to find records of these 100 cases in the library 
 of the Surgeon General's Office, and submit those of which the data 
 area* ce^i Me tome. As these include the cases on which Dr. Fin! 
 claim is based they will suffice for the purpose. The 54 negative cases 
 are omitted. 
 
YELLOW FEVEE. 179 
 
 Case 3 was bitten by a mosguito that had been fed on bloody 
 excrement from another mosquito that had been found inside the 
 mosquito net of a fatal case. The material was allowed to dry for 
 27 days in the test tube and was then moistened with a little sugar 
 and water to prepare it for feeding. (15) There is a marked difference 
 between the method of procedure herein described and that given in 
 1901, (16) when Dr. Finlay said: 
 
 I applied a nocturnal mosquito and allowed it to fill itself from a case of yellow fever. 
 After pricking the side of the insect's abdomen I mixed the blood which escaped 
 with a drop of sterilized sirup and fed with it a fresh culex mosquito, and finally 
 applied the latter to a third soldier (July 29). Two days later, July 31, the soldier 
 went to the hospital with a fever which was also recorded as "abortive yellow fever." 
 
 This case (L. G. P.) was omitted from the paper published in 1881, 
 as stated, but was included in 1891 in the report from which the cases 
 here recorded are taken. 
 
 Case 4 is further discussed in English in a footnote on page 368 of 
 the Kevista de la Asociacion Medico-Farmaceutica, Haoana, Feb- 
 ruary, 1902. (History of illness vague. Did not go to bed or report 
 himself sick.) The first 5 cases were newly arrived soldiers, stationed 
 at Cabanas and who were brought to the city of Habana for exami- 
 nation once in every 5 days. 
 
 Case 9 is cited by Finlay (17) in refutation of pur conclusion (18) 
 that the mosquito is not capable of infecting until about 12 days or 
 more have elapsed after it has bitten the patient. 
 
 Case 55 was a Spaniard, newly arrived, who lived at a country 
 residence. At both attempts to inoculate him the mosquitoes failed 
 to bite; nevertheless he was taken sick August 26. Another non- 
 immune who occupied an adjoining room was taken sick with similar 
 symptoms, a few days later. No further comment is necessary, 
 except that the cases of the Army commission and of Dr. Guiteras 
 were kept under close observation and strict control. Nearly all of 
 Dr. Finlay 's cases were exposed to infection in the city of Habana. 
 Only four of them come within the recognized periods of incubation, 
 viz, Nos. 2, 3, 4, and 66. The first three of these were inoculated in 
 Habana in July, 1881, during which month there were 90 deaths 
 from yellow fever in that city alone. The last was inoculated in 
 August, 1890. In that month 60 deaths from yellow fever are 
 recorded for the city of Habana. 
 
 Finlay has published a great many conjectures and speculations 
 in regard to yellow-fever transmission. Some of these, such as the 
 belief that the disease was transmitted by the mosquito, have been 
 proven by our work, but not in accordance with his ideas. I can 
 nnd no evidence that he has produced a single case of yellow fever 
 by his inoculations. In the first place the mosquito is incapable of 
 transmitting the disease in so short a period as 2 to 5 days after 
 biting the patient. In the second place 7 days must be placed as the 
 extreme limit of incubation in the human being. Our longest period 
 was between 5 and 6 days. Finlay conveniently puts the ordinary 
 limit of yellow-fever incubation between 5 and 22 days. (14) The 
 efficiency of the 5-day quarantine regulation proves that incubation 
 in man certainly does not extend over 6 days, or 7 at the extreme, 
 and in the 30 experimental cases recorded by ourselves and Guiteras 
 the former period has never been exceeded. 
 
180 YELLOW FEN 
 
 TABLE 2. Negative mosquito inoculations of the Army commission. 
 
 
 and number of pe- 
 
 Dayofdteeaw. 
 
 tamo* 
 
 qilito 
 
 rooa 
 
 tan '.' 
 
 Dateofappli- 
 , tttoool 
 
 mosquito. 
 
 NumUT 
 ...' DM* 
 
 qattoai 
 
 Remarks, 
 
 8 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 15 
 
 M 
 
 17 
 18 
 19 
 20 
 21 
 22 
 
 MiM 1 
 
 Seventh 
 
 ***'! 
 
 6 
 6 
 8 
 
 in 
 
 6 
 
 4 
 2 
 3 
 6 
 11 
 6 
 9 
 14 
 
 a 
 u 
 
 13 
 10 
 13 
 16 
 12 
 12 
 15 
 18 
 4 
 11 
 22 
 
 Aug. 11,1900 
 ....do 
 Aug. 12,1901 
 
 Aug. 14.1901 
 log. 10,1901 
 
 Aug. 19,1901 
 Aug. 25,1901 
 
 Nov. 20,1901 
 
 Nov. 23,1901 
 
 -i, 1901 
 
 Nov. 29,1901 
 
 Nov. 28.1901 
 -".1,1901 
 Dec. 2, 1901 
 Nov. 26, 1901 
 
 Dec. 2, 1901 
 Dec. 17.1901 
 Dec. 24.1901 
 Jan. 25,1901 
 
 2 
 1 
 
 1 
 
 1 
 1 
 
 1 
 2 
 1 
 
 1 
 2 
 14 
 7 
 12 
 
 Negative. 
 
 Do. 
 Do. 
 
 Do. 
 
 Negative; p-M-tition. 
 
 Do. 
 Do. 
 
 Do. 
 
 Do. 
 Do. 
 Do. 
 Do. 
 
 Verjrmild. 
 
 
 do. 
 do. 
 do 
 
 iiiil 
 
 Severe. 1 
 
 Bemad 
 
 
 i ; 
 
 I 1 : il 1 
 
 9aoood 
 
 " . 
 
 : : 
 
 Bnood 
 
 
 Third 
 
 do 
 
 do 
 
 do 
 
 Fifth... , 
 
 ....do. 
 
 Third. 
 ...do... 
 
 do 
 
 Fifth 
 
 Moderate. 1 . . 
 i Well marked, 1... 
 
 Third 
 
 Second. 
 
 (Moderate, 1 . 
 1 Well marked, 1. 
 
 Third 
 
 S'TOll'l 
 
 Severe, 1 
 
 do 
 
 do 
 /....do 
 (Fatal 1 
 
 do 
 do 
 Third 
 
 Well marked, 1 
 
 do. 
 
 do 
 do 
 Mild.l 
 do 
 
 do 
 do 
 First 
 do 
 
 Vry mild 
 
 Eighth hour.. 
 
 
 >82F. 
 
 NOTE. The subjects of Experiments Nos. 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and 21 were prov. 
 susceptible by subsequent experimental infection. No. 22 declined a second test. In Experiments 20 and 
 21 the same set of insects and the same subject were used. Four of these insects infected this man six days 
 later, on December 30, 1900. 
 
 In a letter of August 20, 1901, Dr. Finlay (19) states he was con- 
 vinced that extension of the interval between the application of the 
 mosauito to the patient, and subsequently to the nonimmune. would 
 develop a severe attack, such as he was anxious to avoid. One ran 
 sympathize with the humane feeling that prompted him t<> forego 
 positive proof of his theory rather than run the risk of produei 
 severe attack, but it is a fact that on August 22, 1901 . two days Inter 
 than the date of that letter, I saw Dr. Finlay apply to a nonimmune 
 two mosquitoes that had been kept 34 days after contamination. 
 
 I have been impelled to look .up the literature of this Mil. 
 because I have seen several times of late the. statement of Dr. I inlay 
 that the Army Yellow Fever Commission has tacitly ignored his ri^ht 
 of priority. (21) It is too late, after facts have been prov -d and 
 recorded by others, to claim priority mile-, one < an point to un 
 takable evidence, in print, as proof that the facts have been den 
 strated and duly reported. In our preliminary report (J_ Dr. 
 Finlay has been given due credit for priority in advancing and advo- 
 cating the mosquito theory. Nothing more is due to him. He 
 states (21) that he had "many years ago discovered that yellow 
 fever was transmitted by mosquitoes," when in reality he .-imply 
 
YELLOW FEVER. 181 
 
 assumes that to be the case, and the facts recorded by him do not 
 sustain his claim. (23) He further states (21) that his own work had 
 been singularly misrepresented before the American public, and 
 that " among the facts and conjectures which are attributed to the 
 recent investigators there is scarcely one which had not been asserted, 
 demonstrated, or suggested by me, as the result of my personal experi- 
 ments and observations." One can only express admiration for this 
 eminent scientist's persistent adherence to his theory, but the unbiased 
 observer, after a perusal of his numerous writings, must agree with 
 us that while he asserted and suggested everything that intelligent 
 reasoning and profound knowledge could suggest, he failed to pro- 
 duce a single case of the disease. Our results have been confirmed 
 by Guiteras with eight cases and three deaths; (24) Dr. Finlay's 
 assumed results have never been confirmed by a single investigator. 
 In our " Additional note" (25) we report among other instances one 
 in which the bites of 14 insects, applied 4 days after contamination, 
 failed to infect, and the 7 remaining alive failed also to infect 1 1 days 
 after contamination, but on the seventeenth day following contamina- 
 tion the bites of 4 of the same insects produced an attack of yellow 
 fever in "the same individual." During the whole of this time these 
 insects had been kept in a heated room at an average temperature of 
 82 F. If, as is claimed by Finlay, (26) protection is conferred by 
 one or two bites of "recently contaminated" two to five days (19) 
 mosquitoes, this individual, who had received 21 bites from recently 
 contaminated insects, should have been able to resist the bites of 4 
 of the same insects 6 and 13 days later. Should one accept Finlay's 
 extension of the incubation period to 22 days infection might then 
 be erroneously attributed to the bites inflicted 13 days before the 
 onset of fever. 
 
 ^ The Army board worked on an entirely different hypothesis from 
 Finlay, who believed that the infecting agent was retained on the 
 biting parts of the mosquito, that infection was direct, and no interval 
 was necessary. The board worked on the hypothesis that the specific 
 agent of yellow fever was probably one of that group of strict parasites 
 that in nature necessarily pass through two distinct and alternating 
 cycles of development, one within the body of a vertebrate, the other 
 within a blood-sucking invertebrate host. Finlay believed that the 
 bite of a single insect would confer a mild infection and multiple 
 bites a severe one. In my own case, produced by the bite of a single 
 insect, a fatal result was looked for during several days. Dr. Lazear 
 was bitten by a single insect and died. (27) I became so firmly con- 
 vinced that the severity of an attack depended on the susceptibility 
 of an individual rather than on the number of bites sustained, that 
 on October 9, 1901, at Habana, I purposely applied to a nonimmune 
 8 mosquitoes (all I had) that had been contaminated 18 days before. 
 The attack that followed was a mild one ; the temperature never 
 reached 103 F., and dropped to normal on the evening of the fourth 
 day. (27) 
 
 The original theory of Finlay has been variously modified by him 
 from time to time to meet possible contingencies. He now evidently 
 inclines to the belief that development of the germ takes place in the 
 salivary glands of the infected mosquito. (21) 
 
182 
 
 TABLE 3. Positive mosquito inoculations of the Army commission. 
 
 No. 
 
 3S52& 
 
 -aar 
 
 Daysofdl*. 
 
 Ftjfcd 
 
 tST 
 
 Num. 
 
 bard 
 
 ::,.- 
 
 gr 
 
 : 
 (:>. ; T- 
 
 tttinfi 
 
 ;:,-..,- 
 
 Incubation. 
 
 
 
 Severe, l 
 
 
 "5 
 
 
 
 
 
 1 
 
 
 Bteood 
 
 ! 
 
 1 
 
 Aug. 27,1900 
 
 3 day* 7 hours.... 
 
 S.-N ,-r... 
 
 
 Mild. 8.. 
 
 and 
 
 2 
 
 
 
 
 
 2 
 
 Ojrr*r 7 
 
 second. 
 
 First MV 
 
 1 2-16 
 
 4 
 
 Aug. 31,1900 
 
 6 days 
 
 Moderate. 
 
 
 Fatal, 2 
 
 and, and 
 third. 
 Iwittd 
 
 2-15 
 
 
 
 
 
 3 
 
 Severe, l...-. 
 
 Mild, i 
 
 do 
 TbM 
 
 1-19 
 
 5 
 
 Dec. 5, 1900 
 
 3 days 10 boon... 
 
 Pronounced. 
 
 
 Fatal,! 
 
 .do 
 
 17 
 
 
 
 
 
 
 Sever*, 2 
 
 BOMBd ;inil 
 
 r is 
 
 
 
 
 
 4 
 
 Moderate 1 
 
 third. 
 Third 
 
 1 3 
 
 4 
 
 
 5 days 17 i 
 
 Mi!<l. 
 
 5 
 
 Fatal i 
 
 Baooad 
 
 19 
 
 1 
 
 Dec. 9, 1900 
 
 3 days 12 hours. 
 
 Do. 
 
 
 ....do 
 Severe, 2 
 
 Third 
 Second and 
 
 H 
 
 l -i 
 
 
 
 
 
 6 
 
 Moderate, 1.. 
 
 third. 
 Third 
 
 
 4 
 
 Dec. 11,1900 
 
 3 days 20 hours . . . 
 
 ( day. 
 
 
 Severe, 1 
 
 Second 
 
 1-24 
 
 
 
 
 
 7 
 
 Well marked, 2 
 
 First. 
 
 / 10- 5 
 
 ' i:. 
 
 Dec. 21,1900 
 
 3 days 23 hours... 
 
 P ro nou need 
 
 8 
 
 Mild. 1 
 . ..do.. 
 
 do 
 .do . 
 
 1 4-'! 
 17 
 
 1 4 
 
 Dec. 30,1900 
 
 .. ..do... 
 
 
 9 
 
 Well marked 1 
 
 Third 
 
 39 
 
 1 3 
 
 Jan. 19 1901 
 
 4 days 
 
 M.xi.Tiite 
 
 10 
 
 ...do.. 
 
 . .do 
 
 51 
 
 '2 
 
 Jan. 31,1901 
 
 3 days 3 hours.. 
 
 IfDd 
 
 11 
 12 
 
 ....do 
 Fatal, 1 
 
 do 
 Second 
 
 57 
 16 
 
 2 
 1 3 
 
 Feb. 6. 1901 
 Feb. 7, 1901 
 
 3 days 6 hours 
 2 days 22 hours. . . 
 
 Moderate. 
 
 13 
 
 ....do 
 
 Ho 
 
 Third 
 
 QponnH 
 
 1-53 
 
 OOJ 
 
 4 
 
 Sept. 16, 1901 
 
 3 days 
 
 Scvi-re. 
 
 14 
 
 Severe,! 
 
 do 
 
 18 
 
 8 
 
 Oct. 9, 1901 
 
 3 days 8 hours 
 
 Mild. 
 
 82 F. 
 
 A complete proof or disproof of his claim of positive result- id his 
 recorded inoculations could easily be obtained by means of a s< 
 of innocent experiments. It is interesting to note that at ' 
 time when this distinguished authority is in position to ronlirm the 
 results of his first inoculations, if they are susceptible of coniii mation. 
 he takes the ground that inoculation experiments on human 1>. 
 in Cuba must be strictly forbidden. (21) 
 
 TABLE 4. Positive mosquito inoculations oj Dr. Guiteras. 
 
 
 Character of at- 
 tack and num- 
 ber paftatU 
 bitten. 
 
 Day of dis- 
 
 Period in 
 
 mosquito. 
 
 Number 
 of mos- 
 quitoes 
 used. 
 
 DajfetoJ 
 appltoa. 
 
 tion of 
 UMaqai- 
 
 toes. 
 
 Inrutmtlon. 
 
 Character of at uuk. 
 
 
 
 Firrt... 
 Third 
 
 ""* 
 
 19 
 
 1 
 4 
 
 1901 
 Feb. 23 
 AUK. 8 
 
 3 days, 10 hours... 
 4 days 5 hours 
 
 Pronounced. 
 
 
 ..do 
 
 <io . 
 
 19 
 
 4 
 
 .<... 
 
 3 days, 3 hours . . 
 
 Mild 
 
 1 
 
 do 
 
 do 
 
 20 
 
 3 
 
 Aug. 9 
 
 5 days, 3 hours 
 
 Fatal 
 
 7 
 
 do. 
 do. 
 
 I 
 
 :::t 
 
 24 
 24 
 24 
 
 .!! 
 
 1 
 2 
 3 
 2 
 
 Auc. 13 
 
 AUK. 14 
 AUK. 22 
 
 3 days, 19 hours.. 
 3 days, 21 hours.. 
 5 days, 21 hours.. 
 
 .5 'l.ivs 
 
 MM. 
 Fatal. 
 
 M,Hl,-r:Up|v^v,.re. 
 Srvi-rc 
 
 
 
 
 
 
 
 
 
 i Case 4 had been bitten with negative result 10 days previously by 4 mosquitoes 5 days after they had 
 bitten a fatal oaa in the third day of the disease. See Case 33 of Cullerac? table, Aroer.Med., Nov. 23, 
 1901, p. 811. 
 
YELLOW FEVER. 183 
 
 It is unfortunate that Dr. Finlay in his numerous contributions to 
 this subject very seldom gives exact references that would enable one 
 to compare his more recent assertions with his former statements. 
 In regard to his expressed opinion that the great merit of our work 
 consists in our having accurately defined the danger line, beyond 
 which there is a risk of producing severe or fatal experimental cases 
 when nonimmunes are inoculated with mosquitoes whose contamina- 
 tion is more than 10 days old (21), I desire to record my belief, based 
 on experimental observation and on the results obtained by Guiteras, 
 that it is impossible to confer protection or to produce infection of 
 any grade, with an insect that has been contaminated less than a 
 week, and that inoculations with a mosquito contaminated for a 
 shorter period will be absolutely devoid of result. The accompany- 
 ing tables, compiled from our and Guiteras' s cases, afford a substantial 
 basis for the assertion. I deem it a duty to the service to which I 
 belong, to my dead colleagues (Reed and Lazear) and to the profes- 
 sion, to state the facts plainly and clearly. I do not expect that this 
 paper will remain unanswered; nevertheless, I shall decline to engage 
 in controversy and leave the final determination to those who are 
 competent to judge, after they have carefully perused the publica- 
 tions herein referred to. 
 
 The mosquito theory has been practically demonstrated by the 
 Army commission and Dr. Guiteras in two series comprising 22 cases 
 in all. The noncommunicability of the disease by means of fomites 
 has been a matter of common observation in certain localities, and 
 has also been demonstrated practically by our own experiments and 
 those of Havard and his associates. Yellow fever, therefore, is not 
 a filth disease, in the strict sense of the term, and filthy accumula- 
 tions are dangerous in this connection only when accompanied by 
 sufficient moisture to breed mosquitoes under favorable conditions 
 of temperature. Under such conditions standing water is a source 
 of danger, within dwellings or without, and whether dirty or clean, 
 unless it be kept covered or is changed every few days. Yellow fever 
 is a preventable disease; quarantine, if effective, will exclude it, but 
 if the quarantine be evaded and cases gain entrance to a city the 
 disease can be absolutely controlled and finally exterminated by 
 measures directed against the mosquito alone. 
 
 Carter (7) has well shown (8) that first cases are not dangerous 
 until after the lapse of a number of days, for, in his experience, persons 
 in direct contact with them for a few days only never developed the 
 disease after being placed in quarantine. This applies only to the 
 first cases occurring in a town or neighborhood. He found that 
 secondary cases did not appear until the expiration of a number of 
 days, varying from 11^ to 29, the average being 18. This interval 
 represents the time necessary for the mosquito, after biting a 
 patient, to become capable of infecting, plus the period of incubation 
 in the person bitten. 
 
 The greatest obstacle to the control of this disease is the failure to 
 recognize the first cases when they are not accompanied by black 
 vomit. Some of these cases are so mild in character that no physi- 
 cian would dare to pronounce them yellow fever unless he knew the 
 disease to be prevailing at the time. Susceptible persons visiting 
 the house or living in adjoining houses would be bitten and develop 
 the disease in near or distant localities several weeks later, forming 
 
184 i>ow FK\ 
 
 secondary foci of infection. From these secondary foci tertiary foci 
 would in time develop. The diagnosis of bilious remittent fever. 
 dengue, etc., would serve to cover the earlier cases until the appear- 
 ance of black vomit, by which time the infection would : .-me 
 more or less widely disseminated. Such is the history of many 
 outbreak 
 
 The number of mosauitoes in infested districts can always be 
 appreciably diminished by giving attention to surface drainage and 
 the removal of standing water. n< matter ho\v small t he (juantit y or 
 how pure the quality may be. Kain jLrutteis and conduits on huild- 
 .ings should be kept clear and free; cisterns, v\-lU. llu-h tanks, and 
 Other permanent receptacles for water should be kept tightly 
 ered or securely screened; privies and cesspools should be cared 1'or; 
 air vents to cisterns and wefts pro tec ted by screens, and water should 
 never be permitted to stand in any vessel or receptacle within a 
 building longer than three or four days. Ditches and open d< 
 containing water should be frequently ilushed; old cans, < 
 etc., should be removed from the vicinity of duelling-: p<>ls or 
 ponds should be stocked with iish and deepened ai the margins or 
 treated with petroleum. As the stegomvia is largely a house-dwelling 
 and a house-^breedinir in<ect, these and other similar n< wifl 
 
 surely diminish their number and add to the general comfort and 
 protection. In places exposed to yellow-fever infection all ! 
 patients should be protected, nijiht and day, from the bites of i 
 quitoes by the use of netting and wire screens. Strict quarantine 
 measures, local and general, with the isolation of patients and -\ ten- 
 sive and thorough fumigation of the localities where they are found 
 will insure suppression of the disease wherever it may appear. 
 
 In the suppression or control of yellow fever disinfection, apart f i < m 
 fumigation, is a waste of time and money. Natural yellow fever is 
 transmitted by the mosquito, and always and only by the mosquito. 
 The harmlessness of fomites has been fully demonstrated by our 
 experiments in 1900 and 1901, in which three young Americans slept 
 for 20 consecutive nights in a room garnished with articles soiled with 
 black vomit, bloody fecal discharges and urine from fatal and other 
 cases of yellow fever. Three and four large boxes were packed and 
 unpacked with these articles night and morning by these nommmu 
 who suffered no disturbance of health from these exposures. The 
 room was 20 feet by 14 feet, double walled, tightly ceiled. Iieated to 
 above 90 F. and dark. Water was always present to keep the at i 
 phere moist. Two other nonimmunes then occupied the room 1 
 nights while additional articles of bedding and clothing were added. 
 They slept in the garments and between the sheets that had covered 
 cases of yellow fever, some of which were fatal. The result of this 
 second exposure was nil. A third attempt was then made with 
 additional nonimmunes equally without success. Not the slight* >>t 
 indisposition followed close anil intimate contact with this repulsive 
 material in any case. Temperatures and pulse rates were recorded 
 at regular and frequent intervals. Four or these seven noniinnmnes 
 were subsequently infected by blood injections and by means of 
 infected mosquitoes. A fifth resisted the mosquito once (28) and 
 declined further attempts at inoculation. 
 
 Yellow fever has been eradicated from Habana, one of its endemic 
 homes, by the institution of measures directed against the mosquito, 
 
YELLOW FEVEE. 185 
 
 after extreme cleanliness and energetic disinfection had proved a 
 dismal failure. Several cases subsequently imported into that city 
 have been handled with impunity by guarding the patients against 
 the bites of those insects. A small outbreak in Santiago de las Vegas 
 in 1901 was promptly suppressed by Col. Gorgas by the use of mean 
 directed only against the mosquito. On those who decline to accept 
 such evidence must rest the burden of proving that the disease is 
 transmitted in some other way before their position can be sustained. 
 
 REFERENCES. 
 
 (1) Medical Inquiries and Observations, Benjamin Rush, M. D., Philadelphia, 1805 
 vol. iv., pp. 10, 77, 175. 
 
 (2) An Essay on Yellow Fever, by B. B. Strobel, M. D., Charleston, S. C., 1840, p. 
 162. 
 
 (3) Report of Sanitary Commission of New Orleans on the Epidemic of Yellow Fever 
 of 1853, New Orleans, 1854, vol. i, pp. 266, 278, 540. 
 
 (4) The Epidemics of New Orleans, by Bennett Dowler, New Orleans, 1854, p. 44. 
 
 (5) La Roche on Yellow Fever, Philadelphia, 1855, vol. i, pp. 67, 77, 79. 
 
 (6) See footnote 2, p. 87, citing from the London Medical Gazette for August, 1839. 
 
 (7) New Orleans Med. and Surg. Jour., May, 1900. 
 
 (8) Medical Record, N. Y., June 15, 1901. 
 
 (9) Anales de la Academia de Ciencias Medicas de la Habana, Havana, xxvii, 
 1890-91. p. 501. (Finlay.) 
 
 (10) Original Article republished in English in the Reyista de la Asociacion 
 Medico-Farmaceutica, Havana, Cuba, Jan. and Feb., 1902. (Finlay.) 
 
 (11) Finlay: Ibid., pp. 362 and 369; also Edinburgh Med. Jour., Oct., 1894, p. 334. 
 
 (12) Proceedings of the International Congress of Hygiene and Demography, Buda- 
 pest, 1894, p. 702. 
 
 (13) Edinburgh Med. Jour., vol. xli, 1 pp. 523 to 526. 
 
 (14) Finlay: Amer. Jour. Med. Sci., n. s., vol. xcii, 1886, pp. 402, 403. 
 
 (15) Footnote to p. 369, Revista de la Asociacion Medico-Farmaceutica, Havana, 
 Feb., 1902. 
 
 (16) Medical Record, N. Y., Feb. 9, 1901, p. 203. 
 
 17) The Journal A. M. A., April 13, 1901, p. 1041. 
 
 18) Ibid., Feb. 16, 1901, p. 439; 3d conclusion. 
 
 19) Medical Record, Aug. 31, 1901, p. 344. 
 
 (20) Case 8 of Dr. Guiteras' series, Amer. Med., Nov. 23, 1901. 
 
 (21) See reprint, p. 8, on "Method of Stamping Out Yellow Fever, Etc.," by Dr. 
 Charles Finlay, M. D., Conference of State and Provincial Boards of Health, New 
 Haven, Conn., Oct., 20, 1902, and Medicine, Detroit, March, 1903, pp. 175, 179. 
 
 (22) Phila. Med. Jour., Oct. 27, 1900. 
 
 (23) Sternberg, Amer. Jour. Med. Sci., new series, vol. cii, 1891, p. 627, and Nuttall, 
 Johns Hopkins Hosp. Reports, vol. viiii, 1899-1900, p. 27. 
 
 (24) Amer. Med., Nov. 23, 1901. 
 
 (25) The Journal A. M. A., Feb. 16, 1901. 
 
 (26) Finlay: Edinburgh Med. Jour., Oct., 1894, p. 335. 
 
 (27) The Etiology of Yellow Fever, Amer. Med., Feb. 22, 1902, Case 2. 
 
 (28) Case 22, Table 2. 
 
CHAPTER 2. 
 
 ARKS ON EPIDEMIC OF YELLOW FEVER IN BALTIMORE.' 
 By JAMBS CARROLL, M. D., Burgeon United States Army, Washington, D. C. 
 
 MR. PRESIDENT AND GENTLEMI \ <>r THE ALTJMM taaa EATI 
 Instead of a strictly technical theme. I liave chosen one that may 
 f more general interest, and which formerly demanded the at ten- 
 tin n of two of the most brilliant minds among the early teachers of 
 the university. 
 
 Dr. Nathaniel Potter, a former pupil of Dr. Benjamin Ku-h, and 
 afterwards the first professor of theory and practice of medicine in 
 the university, held in 1703 that yellow fever was n.t emit a:ious, 
 and he communicated this opinion to Dr. Rush in writing. A 
 to his own statement, he believed that he was the only person in 
 America who held that opinion, and in 1795 he prepared to defend 
 his belief in an inaugural thesis to be read at the next comm- 
 inent of the University of Pennsylvania, of which he was a student. 
 He was dissuaded by Dr. Wistar on the grounds of propriety 
 expediency. Dr. Potter states that in 1797 Rush > contention that 
 the disease was contagious was first publicly attacked by I>r. 
 B. Davidge, one of the founders ana the first professor of sur 
 and obstetrics in this school, whose paper was published in 
 Federal Gazette, of Baltimore, on the 30tn day of November. 17'.'7. 
 Dr. Davidge subsequently enlarged his paper n ..lied it in a 
 
 volume entitled "Physical Sketches," published in Baltimore in 1814. 
 On account of the importance of this city as a seaport, in almost 
 constant intercourse with the West Indies, yellow fever JUUM have 
 been introduced a great many times, yet the only important epi- 
 demic outbreaks of the disease took place in 17iM. 17 ( >7, 1800, and 
 1819. It is notable that all the outbreaks began at Locust Point, 
 or about the docks and wharves, and they can DC traced direct I 
 indirectly to the shipping. The relatively high ground upon which 
 the city stood, and tne distance from the city proper to the wh.-; 
 and shipping, explain why the intcrurban residents suffered but little, 
 while those Jiving upon the poorly drained, low-lying di near 
 
 the river were compelled on such occasions to flee for saf < 
 
 It can be easily shown that yellow fever was frequently confounded 
 with malaria; indeed, it was strongly contended that the t\\> di- 
 eases were one and the same, tl nee being only in the .1. 
 
 of intensity. Then, while many contended that the disease 
 imported, and though their contentions could be supported by sworn 
 testimony, there were others among the leaders and teachers in the 
 profession who held, \\ith Ku>h, that since the infection was j: 
 prevalent in poorly drained localities, the water and decomp 
 vegetable matter must be necessary for the generation of the poison, 
 which was manifestly conveyed through the atmosphere. The 
 
 Hoipital li venlty of Maryland, Feb. 15, 1905. 
 
YELLOW FEVER. 187 
 
 general restriction of the disease to the localities described, the 
 observation that many persons who visited those localities for only a 
 few hours became infected, while in other localities no infection took 
 place, even among those who were intimately associated with the 
 patients, proved the disease to be one of locality. With the observa- 
 tion that if the wind blew strongly from the direction of the infected 
 locality toward the city, that within a few days the disease also ex- 
 tended toward the city, it was concluded, with reason, that the poison 
 must exist in the atmosphere, that it was transported by the winds, 
 and that infection could only result from the inhalation of this poison, 
 which was believed to be gaseous in nature. This agreed with Syd- 
 enham's theory of the epidemic constitution of the atmosphere, which 
 was supported by Rush and his pupils, and which then seemed to 
 offer the only explanation of the recorded observations of centuries. 
 If we admit the mosquito as the sole carrier of the disease, we will 
 be prepared to acknowledge that their observations were, in the 
 main points, strictly accurate; that their reasoning was logical, and 
 the deductions fully justified by the premises. It then becomes very 
 easy to understand how the disease became one of lowly situated 
 and poorly drained localities; how it was transmitted by the atmos- 
 phere ; how it failed to spread in certain locations ; and how it dis- 
 appeared upon the appearance of a heavy frost. The observation 
 was actually recorded by a Baltimore physician that during the 
 epidemic mosquitoes became an intolerable pest, while but a short 
 time before no mosquitoes were observed. 
 
 How beautifully this observation agrees with our present knowl- 
 edge that the yellow-fever-carrying mosquitoes can be conveyed on 
 vessels ; that in the warmer season of the year they will multiply on 
 shore, gradually extending from house to house, breeding in and 
 about the dwellings (for they are domesticated insects), and that 
 they become infected only after feeding upon a patient. The impor- 
 tation of the mosquito explains the appearance of this insect in places 
 where it usually does not exist; it explains the occurrence of the 
 earlier cases among persons who either visited the vessels or wharves 
 or docks, or who lived in the vicinity of them. It also explains why 
 favorable localities were visited by the infection only, as a rule, when 
 they received shipping; while localities equally favorable to the 
 infection, but far from the shipping, remained free from it. Of course, 
 the absence of the proper mosquito explains the failure of the disease 
 to spread to any extent in the city proper. This stood upon ground 
 that was high and dry, and it was at that time some distance from 
 Fell's Point, the location of Sugar House Wharf where many of the 
 vessels from the West Indies probably made their landing. Assum- 
 ing that at the Sugar House Wharf cargoes of sugar were unloaded, 
 we are reminded that sugar is a favorite food for the yellow-fever 
 mosquito, and that it can subsist on this and water alone for months. 
 Now Sugar House Wharf was at Fell's Point, and most of the out- 
 breaks began at Fell's Point, where, presumably, the largest number 
 of mosquitoes was imported. 
 
 During the epidemic of 1794, 360 deaths were recorded. Dr. 
 Drysdale reported * that he saw his first case just before death on the 
 7th of August, at Bowley's Wharf, in the town, and on the 14th, 
 
 The Philadelphia Medical Museum, 1805, 1 26. Letters written by Dr. Drysdale to Dr. Rush. 
 
188 YELLOW FEVER. 
 
 20th, 22d, and 23d of the same month he saw five additional < 
 at the same part of the wharf. There \\ere also at the same place 
 some other cases which did not come under his care. Dr. Prysdale 
 states that there was considerable sickness at Fell's Point after the 
 death of his first case, and many deaths had occurred suddenly, 
 >r after a short indisposition. An investigation was made l>y three 
 of the most respectable physician-, who reported that the prevailing 
 r was the common epidemic of the season which visited the 
 Southern and Middle States annually, viz, the bilious remit tent 
 fever. The number of cases now rapid Iv increased, so that 1>\ 
 tember 25, in about seven weeks, five physicians were attacked and 
 two of them died. The cases had become so numerous that Dr. 
 Coulter visited and prescribed for more than 120 per-"ii- daily. By 
 the end of the month many families had sought refuse in the country. 
 During this time the city remained unusually healthy, and although 
 some persons infected at the Point died in the city proper, in that 
 location the disease failed to spread. 
 
 In his ninth letter of a series to Dr. Rush he state- that yellow 
 fever was first discovered at two points, remote from each other, vi/. 
 at Bowleys Wharf in the town-, and at Fells Point. Many cases 
 occurred throughout the town, but these originated either from com- 
 munication with Bowleys Wharf or the roint, and the infection 
 could be distinctly traced to one of those two places. Beinir pn//led 
 to explain why the infection was confined to those two places, he 
 found that the first cases on the Point were confined to h< 
 whose cellars were filled with stagnant, putrid water, and he 
 found black, putrid, and offensive water beneath the stores in which 
 the sick resided at Bowleys Wharf. Almost all those who 
 first affected were newcomers. Dr. Drysdale describes the Point 
 as being low and flat; its streets generally not paved; its alleys 
 filthy, and the ground around it marshy in many places. The 
 frequent warm rains kept the noxious places constantly moi>t under 
 a hot sun. We can easily recognize these as conditions favoraLle 
 to the multiplication of mosquitoes, and the domestic habits of the 
 stegomyia mosauito would tend to keep the infection rather do-ely 
 confined to these localities. He further makes the significant 
 statement that remittents were present from a very early period. 
 It is more than probable that many of these remittents were true 
 yellow fever, because under the belief then prevailing, that these 
 were simplv the prevailing types of summer fever, they would not 
 be reported.. It is also probable that if occasional cases were known 
 to have been yellow fever, some physicians would have concealed 
 them from the same motives that prevail to-day. He could discover 
 no satisfactory evidence of the importation of the disease, though he 
 states that the Triumph arrived at the wharf about the last of June, 
 with almost all the crew indisposed, and previous to this there lay 
 at the wharf a schooner whose captain had died on the voyage from 
 the West Indies. The fact alone, however, that vessels from the 
 West Indies came up to the wharf is sufficient to indicate to us 
 the source from which the infection was received. The following 
 sentence toward the end of the ninth letter is of extreme interest: 
 "Locusts were not more numerous in the reign of Pharaoh than 
 mosquitoes through the last few months; yet these insects were very 
 rare only a few years past, when a far greater portion of Baltimore 
 
YELLOW FEVEK. 189 
 
 was a marsh." With wonderful acuteness of observation he remarks 
 that some families at the Point avoided yellow fever by carefully 
 precluding all communication with the sick, and that vessels also 
 preserved their crews in health by removing to a distance from the 
 wharf and preventing the sailors from going ashore. As soon as one 
 infected person came on board he quickly infected all or most of the 
 crew. He instances one man who contracted the disease on shore 
 and carried it on board the ship PTioenix, whose crew was healthy. 
 These all became infected and 5 out of 12 died. As the result of 
 these observations he very naturally concluded that in some instances 
 the fever proved contagious. These, and other cases cited, are 
 now so easily explained by the mosquito theory that we can not 
 appreciate the perplexity of the problem as it formerly presented 
 itself for solution. The most accurate and careful observation 
 yielded results that were apparently contradictory. All honor to 
 Dr. Drysdale, whose tenth and last letter of the series was written 
 to Dr. Rush in December, 1794. 
 
 Some further interesting references to this epidemic were published 
 by Dr. John B. Davidge in 1798 and subsequently rewritten by him 
 in a treatise on yellow fever, published in 1813. He makes the inter- 
 esting statement that the yellow fever first appeared in the last of 
 August, but the common bilious fever prevailed at Fells Point from 
 June. A lady from Philadelphia was attacked with yellow fever, 
 on Charles Street, and she had black vomit, but no other person in 
 the family or neighborhood was attacked during the whole season. 
 He no ted 'that the disease extended in the direction of the prevailing 
 winds, and that it was conveyed bv a northeast wind all along 
 Federal Hill and the west end of the basin. A considerable number 
 of cases occurred in the city and many who had attended the launch- 
 ing of a frigate (near the water, of course), subsequently suffered 
 from yellow fever, and several of them died, but no single person in 
 the city contracted the disease from them. 
 
 Concerning the prevalence of yellow fever in Baltimore at that 
 time (1798), Dr. Davidge writes: 
 
 A physician in conversation the other day told me that he had met with the yellow 
 fever in Baltimore ever since he had lived there, which is 15 or 20 years. It is vio- 
 lating all obligations of decency and truth to say that it is of recent date. 
 
 This statement was probably correct, for every importation of the 
 disease is not necessarily followed by an epidemic. In Baltimore 
 and other places where the mosquito, Stegomyia fasciata, is not 
 normally present, an epidemic is not possible, after the introduction 
 of any number of cases, provided the mosquito be absent. For the 
 production of an epidemic the introduction of infected mosquitoes 
 alone during the hot season may suffice, because the mosquitoes 
 deposit their eggs, and in a week or 10 days another brood will have 
 become mature. The insects of this new brood must bite a patient 
 in the first three or four days of the attack in order that they may 
 become infected. Should only one or two infected insects be brought 
 in and should they die (as frequently happens) immediately after 
 depositing their eggs, then the disease would appear only in the 
 persons first bitten by them, and these would have passed beyond 
 the infective period by the time the new brood had matured. Should 
 the infected insects, however, have remained alive, and should they 
 have bitten other persons, at intervals of a few days in succession, 
 
190 YELLOW PEVBB. 
 
 these persons would be in the proper stage of the disease at the 
 maturini: of the new brood to enable them to become infected. 
 When the proper mosquito has been previously introduced into a 
 favorable locality in the proper season, or when the mosquito, 
 Sttgomyia fascia /J/.i- naturally present, the introduction subsequently 
 of a single case may produce an epidemic. The facts above stated 
 will readily explain the frequently reported appearance of sporadic 
 cases without the occurrence of secpncfary ones. 
 
 We can now see that the immunity against the disease enjoyed by 
 proper evidently depended upon its high and dry location. 
 ndered the conditions unfavorable for the multiplicai inn of 
 the mosquitos that were imported. In tin- regard Baltimore 
 more fortunate than Philadelphia, which was lower and contained 
 B standing water. Hence, the mosquitos were more abundant 
 and the disease spread uniformly. This led Dr. Rush to contend that 
 the disease must be contagious, while Dr. Davidire held t hat t he 
 tairion was local, and existed only in the air of certain fmm 
 
 where it might be wafted by the winds in any direction. Dr. 
 asserted (p. 84) that they had the m<t stubborn and in. 
 proofs, in those cases occurr in L: about the whar\ex ;( nd at I-VIU Point. 
 that the disease was incapable of supporting it >elf. When these- 
 noved u]> into the city their virulence died with them, i 
 who died; and, he writes, "from those who recovered, all mischief and 
 supposed contagion evanesced into empty air. which bore it to the 
 pages of medical writers, and not to the bodies of healthy attendants. 
 This was the result in 1794 and 1797." 
 
 The importance of tin's observation can hardly be overestim.: 
 it shows the sagacity and care with which the epidemic was studied 
 by these devoted men. Dr. Davidge learned the truth, and that 
 truth unfortunately still remains to-day a hidden mystery to many 
 of our practitioners, notwithstanding the recent absolute demon 
 tion of it beyond a shadow of a doubt. 
 
 In connection with the now known mosquito propagation of the 
 disease, an observation recorded by Dr. Nathaniel Potter ' in this 
 outbreak of 1797 deserves mention. He tells us that previous to the 
 17th of September the fever had been conlined to certain place- and 
 to such as had breathed the air evolved from them: on that <! 
 strong southeast wind wafted the effluvia in a northwest direction 
 and diffused it among the inhabitants of the upper part- of I ied- 
 erick, Gay, South, and Calvert Streets, who became immediately 
 implicated in all the horrors of the fever. 
 
 In 1800 there appeared the severest outbreak the city has Known. 
 The mortality from yellow fever is recorded to have been 1 . l'.7. or 
 
 about 1 in 50 of the population of 60,000. Again the di>ea-e I 
 at Fells Point, on the borders of the cove, which extended from 
 Jones Falls to the interior. The faculty of medicine of the city, after 
 investigation, reported to the mayor that in their belief the disease 
 was i or ted. but originated in t he cove from thostagnat ion 
 
 putrefaction of filth uni. 'iimer's sun. The fir-: t v. o 
 
 peared on the 2d of May, 2 another on the Sth of June, one on the 
 9th, 10th, and Kith: then from the -I'd they became more mime. 
 
 - .~.. on Contagion, by Nathaniel Potter, M D., Baltimore, 1818, p. 20. 
 
 * Medical Repository, New York, 1801, vol. IV. p. 361. 
 
YELLOW FEVEE. 191 
 
 It is unfortunate that we have no detailed description of this epi- 
 demic, the most disastrous the city has ever experienced. 
 
 A few cases are reported for the years 1802-1805. 
 
 The next important outbreak took place in 1819 following the 
 arrival of an infected ship from Habana. 1 In a letter to the editors 
 of the Medical Repository, Dr. Pierre Chatard, 2 of Baltimore, writing 
 October 19, cites the first cases as follows: The fever commenced 
 raging at Fells Point in the beginning of July, and never ceased there 
 until the end of October. It appeared also at Smith's Dock toward 
 the end of July, carrying off five persons whose names are given, and 
 others. The persons named had countinghouses on the dock or in 
 the vicinity. m> other cases appeared at the dock for two months, 
 at the end of which time two more appeared. Dr. Chatard attributes 
 the absence of cases during this time to the great quantity of lime 
 that had been strewn on the ground by order of the mayor. The lime 
 was again applied and the cases ceased. At Fells Point the disease 
 raged for three months before it subsided. The greater part of the 
 population retired to the healthier portions of the city, and many of 
 them sickened and died there, but none of their friends or relatives 
 suffered in consequence. We are told by Dr. Chatard that the 
 epidemic focus on the Point never exceeded seven or eight thousand 
 square feet. This information he regarded as precious because it 
 demonstrated the noncontagiousness of the disease and the value of a 
 local quarantine. 
 
 Among the most interesting records of this epidemic are the letters 
 and other documents published by authority of the mayor in 1820. 
 These contain the actual opinion and experiences of the physicians, 
 and they show a remarkable unanimity in the belief among the Balti- 
 more physicians that the disease was noncontagious. The persist- 
 ency with which the infection originated and remained in the vicinity 
 of shipping, wharves, etc., is generally commented on. Dr. Clendinen 
 reports that his first cases were located at the southeast corner of 
 Fells Point, and several of them appeared among foreigners on board 
 the shipping, persons who had been healthy previous to their arrival. 
 This invasion by the disease of healthy ships tied up to the wharves 
 appeared to be indisputable evidence of the poisoned condition of the 
 atmosphere. Of course it is hardly necessary to say here that these 
 vessels were simply invaded by infected mosquitoes. Dr. Clendinen 
 was a resident of the Point, and he states that his family had suffered 
 from the disease and he had lost a student, an assistant physician, 
 and some of his best friends. Dr. Samuel B. Martin, after enumerat- 
 ing 34 of his earlier cases, with their location about the wharves and 
 shipyards, states: 
 
 These will suffice, I think, to show the course the disease took in its commencement, 
 traveling regularly along the course of the water and infecting the streets in the vicinity 
 thereof. My most violent cases were near the water's edge or contracted there. 
 
 No mention of this epidemic would be complete without a reference 
 to the little book by Dr. David M. Reese, entitled " Observations on 
 the Epidemic of 181 9," a book which every one interested in the 
 subject should read. According to him, some persons attributed the 
 epidemic to the arrival of the schooner Adventure from the West 
 
 1 Carpenter on Yellow Fever, New Orleans, 1844, p. 18. 
 
 2 Medical Repository, New York, vol. 20, 1820, p. 261. 
 
192 W>W 1KVER. 
 
 Indies, laden with coflfee, while others looked with suspicious eyes 
 upon the schooner Proserpine laden with hides and coil'ee. Both 
 teasels were ordered to the quarantine -round, hut were soon per- 
 mit ted to return because, after a reexamin at ion hy the health ollicer, 
 their cargoes were found to be in a sound condition. 
 
 ingto the time when 1,016 cases had been reported hy the 
 physicians, Dr. Reese states that of all of these only rj were supposed t<> 
 nave originated in the city. He calls attention to the remarkahle 
 fact that, in almost every instance where a person visited the Point 
 at niirht the contracted they disease, while those who were there only 
 in the daytime escaped with impunity. He further remarks that 
 those of tne Baltimore physicians who became infected sullVred in 
 consequence of paying a \ i-it hy ni.Lrht to the source of infection, or 
 to the vicinity where the cause existed. Several ph \\ h< > had 
 
 attended patients in the daytime in the very cent er !' the infection. 
 and through the whole course of the fever remained exenmt until hy 
 vi-itini: the district once in the night they contracted tne di 
 This accords perfectly with the mosquito theory and wit h t he t wilirlit 
 habits of stegomyiafasciata, the particular mosquito n >w know n ' 
 concerned in the transmission of the disease. It i> al-o in accord with 
 the experience of the American troops near Habana. Soldiers who 
 visited the city only between the hours of 9 a. m. and 4 p. in. remained 
 free from the disease, while among those who became infected there 
 were but few who did not acknowleo!ge having spent a niirht or a part of 
 anight out of the barrack. Let us now consider what evidence, if any, 
 collected by these closely observant Baltimore physicians could he 
 used to support the mosquito theory to-day. Firstly, t i nied 
 
 the presence of an unusually large number of mosquitoes; secondly, 
 they observed that the infection was localized in the low, wet disi rid s 
 near the river and shipping; thirdly, they noted that the infection was 
 contracted mostly at night; fourthly, they showed that in the higher 
 and drier ground of the city proper the disease was absolutely non- 
 contagious; fifthly, they reported that the disease traveled in the 
 direction of the prevailing winds, w r hen these were strong and hlew in 
 one direction ; and, sixthly, they were familiar with the lact that yel- 
 low fever was most apt to prevail when the mean temperature was 
 high, and they knew perfectly well that the disease was stamped <.m 
 by the frost. To this we. can add nothing more than the direct. 
 implication of the mosquito. 
 
 Of course, a mistake was made in the failure to recognize the 
 imported nature of the disease, and strong protests were written 
 against the quarantine methods then in force against Baltimore by 
 Philadelphia, Wilmington, and other places. These * quarantines 
 were established in the belief that the disease was contagious, The 
 Baltimore physicians, having the strongest proofs that it was 
 felt that they were treated with undue seventy. In a low-lying city 
 like Philadelphia, where mosquitoes were numerous, there was JIM i- 
 fication for the belief in contagion, so that, while both were partly 
 wrong in their opinions, under the circumstances the method of 
 Quarantine was a justifiable and proper one to adopt for their sal 
 On the other hand, the lax cjuanmtine system at Baltimore was a 
 source of danger; still it was justifiable on the ground of the availa- 
 ble evidence to show that yellow fever was not contagious and upon 
 the belief then prevailing that all infectious fevers were the result 
 
YELLOW FEVER. 193 
 
 of putrefaction. Hence, if a vessel were clean and her cargo in good 
 condition, it was assumed that she could not harbor the seeds of the 
 disease and she was permitted to come into dock and unload. 
 
 In the management of the epidemic the wise policy was adopted of 
 advising all persons to flee the infected location and seek a residence 
 upon high ground without the range of the infection. This the major- 
 ity did, many going to the country or remaining nearby, while some 
 refused to leave their habitations, and these latter furnished the fuel 
 for the continuance of the pestilence. This epidemic is said to have 
 cost the city 350 lives. 
 
 The kindly concern shown for the welfare of the destitute poor 
 stands out brightly in the history of this outbreak. It became nec- 
 essary to remove the healthy poor from Fell's Point and provide 
 means of shelter and sustenance for them until it was safe for them 
 to return. A committee was appointed who visited a Mr. Owen Dor- 
 sey to solicit the use of a ropewalk owned by him. This was granted 
 free of charge and the removal began. More room was soon needed, 
 and a Mr. Christopher Chapman gave up another adjacent ropewalk, 
 1,000 feet long, for the purpose. This was not sufficient and more 
 than 100 tents and marquees were then pitched and filled. Over 
 1,000 persons were received, made comfortable, and supplied with 
 provisions and every necessity. The corporation appropriated 
 $1,000, but this was returned, the donations of money and supplies 
 being ample for all purposes. Notwithstanding the partial depopu- 
 lation, business depression, failure of some of the leading commer- 
 cial houses and one of the banks, over $4,000 in cash were contrib- 
 uted and liberal donations of food, clothing, etc., poured into the 
 warehouses designated to receive them. The neighboring farmers 
 contributed flour, fruit, and vegetables as well as money, and George- 
 town, D. C., contributed $700. A soup house was established at 
 the encampment, and this supplied over 100 gallons of rich, whole- 
 some soup daily. This enterprise was undertaken by three energetic 
 gentlemen Messrs. Stewart, Mosher, and Coale and through vol- 
 untary contributions of material and labor the total outlay required 
 was only $10. The camp was maintained for 53 days, and when it 
 was broken up, on the 25th day of October, each person was sup- 
 plied with provisions for three davs. There were only six deaths 
 in the encampment and five additional in the hospital of persons 
 who contracted the fever at the Point and were carried from the 
 camp to the hospital for treatment. The sick among the poor were 
 cared for at the hospital at the expense of the city. Food, luxuries, 
 and stimulants were provided for distribution upon the order of any 
 practicing physician. It is estimated that by these means several 
 hundred lives were saved, and the record is one of which Baltimore 
 should be proud. The mayor, Edward Johnson, was a man of 
 Christian character, high courage, and strong determination. ^ Dis- 
 regarding protests, the mayor and many of the board of health visited 
 the hospitals during the height of the epidemic, and by their example 
 inspired others with confidence in the noncontagious nature of the 
 disease. Dr. Reese wrote of him : 
 
 Mr. Johnson is one of the few individuals with whom, when interest and duty are 
 in opposite scales, the latter will ever predominate. 
 
 After this disastrous epidemic a few cases occurred annually until 
 1805, and perhaps later. 
 
 79965 S. Doc. 822, 61-3 13 
 
194 YELLOW FEVER. 
 
 Ton cases are reported to have appeared at Kort McHenry in 1^ 
 and the disease was believed to conic from infect Is in <|iiaran- 
 
 tine nearby. It is probable, as has been stated 1>\ l>r. John M 
 sporadic outbreaks were frequent at Kells Point until 1 
 In tliis \car I>r. Kemp, of the hoard of health, had (lie infected 
 district drained and cleaned. It is said to have l>een free from the 
 ase from then until \cept durin.i: the sii^pen>ion of com 
 
 e dnrinjr the Civil \\'ar . \\hen a small outhivak <f the t 
 undoubtedly appeared, though the cases \\ere not oilicially reported. 
 
 In this review of the epidemics at Baltimore, the literatim 
 which is very scant, I have confined myself to a simnle narrati- 
 the facts which seem to be of general interest, and I nope that >ome 
 >u mav be stimulated to read for yourselves the records \\ ritten 
 :ien of this city, some of whom were teacher- in our university 
 and of whom you have every reason to be proud. 
 
 i History of the Epidemic in Baltimore in 1870. Reports of American Public Health Association. Vol. 
 
 > f , p. 244. 
 
 * Baltimore Physician and Surgeon, Vol. VI. p. 37. 
 
CHAPTER 3. 
 
 YELLOW FEVER: A POPULAR LECTURE. 1 
 
 By JAMES CARROLL, M. D., assistant surgeon, United States Army. 
 
 Yellow fever, or yellow jack, as it is more familiarly called, is so 
 far as our knowledge goes, strictly an American plague or pestilence, 
 and our earliest authentic accounts of this disease record its occur- 
 rence in the West Indies at the middle of the seventeenth century. 
 By one or two of the older writers it is reported to have been trans- 
 ported there from Siam, but this seems unlikely, because yellow 
 fever has never been shown to be an oriental disease. Before the 
 time of Sydenham, oriental plague, typhus fever, smallpox, cholera, 
 pernicious malaria, and yellow fever were all called putrid or pestilen- 
 tial fevers; it was believed they were due to the same cause and 
 that they were transmitted through the atmosphere as visitations 
 from God. At that time the science of medicine stood upon such a 
 low plane that the best English physicians were just beginning to 
 learn that there were differences between measles and smallpox, 
 typhoid fever or typhus fever, and malaria, etc. Harvey had only 
 recently announced the circulation of the blood and Malpighi had 
 followed him with a demonstration of the blood corpuscles in the 
 smaller vessels (capillaries) uniting the arteries and veins. Peruvian 
 bark, that blessing in malarial fevers, was barely known at the time 
 when yellow fever first prevailed at Barbados, Jamaica, Santo 
 Domingo, and Martinique, and later at Vera Cruz. In 1761 the 
 disease was carried from Vera Cruz to Habana by the Spaniards, who 
 lost 3,000 persons from it in that year alone, and in 1780, out of an 
 army of 8,000, about 2,000 died of yellow fever within two months 
 after landing at Habana. It is further reported that in 1794 there 
 were over 1,600 victims to yellow fever in the Spanish garrison and 
 squadron at Habana. More recently, for the 10 years from 1870 to 
 1879, inclusive, 11,746 deaths are recorded for the city of Habana 
 from yellow fever alone. Spain paid dearly for the Pearl of the 
 Antilles in both men and treasure, for, besides decimating her troops 
 in Cuba, the disease followed them across the Atlantic and appeared 
 in epidemic form in various cities of the Peninsula from time to time. 
 
 The fearful mortality attendant upon this disease is well brought 
 out in the accounts of some of these epidemics. For instance we are 
 told by an English physician, Dr. O'Halloran, 2 who studied the epi- 
 demic in Barcelona hi 1821, that the general hospital received 830 
 patients suffering from yellow fever, and of these no less than 749, or 
 90 per cent, died. This keen observer contends the disease can not be 
 contagious, but is due to some local infection of the atmosphere, and 
 in support of his contention he cites numerous instances during the out- 
 
 1 Delivered at Galveston, Tex., Apr. 12, 1905, under the auspices of the University of Texas. Reprinted 
 from American Medicine, Vol. IX, No. 22, pp. 907-915, June 3, 1905. 
 
 2 Remarks on the Yellow Fever, by Thomas O'Halloran, M. D., London, 1823. 
 
196 YELLOW FEVER. 
 
 break referred to, showing the disease was not aiul could not be di- 
 rectly contagious, because duriiu: the epidemic thousands of persons 
 fled from the city to the- country. iiMshiaing those who had slept with, 
 nursed, and been intimately associated with the sick. traveling in many 
 instances in the same cart- <>r carriages that had been the 
 
 transportation of nalicnis. and e\cn the dead, and after carry in;; with 
 them the penoiuJ cll'ects of those who had died of the disease. Still. 
 ;her cases f.>ll..\\ed in the districts to which these people lied and 
 evidence appeared to be indisputable that the disease -pread by 
 contagion in certain localities within the city or its environ-, and the 
 lusion was arrived at that the contaL'i"n could not e\M in the 
 country, but originated de novo in certain localities in the cities, as a 
 result OI peculiar atmospheric and local conditions. It v rvcd 
 
 that the nuns of the u r cneral hospital who were thrown into frequent 
 and direct contact with the sick escaped t lie disease, while in the 
 valescent hospital the president, the head apothecary and the superin- 
 tendent. none of whom had ever entered the rooms of the sick. 
 who had taken every precaution not to communicate with the sick 
 nor with anything De&ngjng to them, all fell ill. Of course, now 
 that we know that natural or nonexperimental yellow fever can only 
 be contracted through the bite of a contaminated mosquito, it is 
 quite clear that the presence or absence of the disease in certain locali- 
 ties means simply the presence or absence of contaminate! 1 moB- 
 quitos. As we view the subject now, the yellow fever mosquito 
 brought to Spanish ports by vessels coming from Habana, and be in;; 
 a house mosquito, it multiplied in those cities during tin 4 warm se, 
 It was then at hand to receive and transmit the infecti< -us a-ent when- 
 ever it encountered cases of the disease, and these were frequent ly im- 
 ported. Upon the appearance of frost the mosquito went into hiber- 
 nation and the epidemic promptly ceased. As the insect was an im- 
 ported one it was not present in the country districts, consequently 
 there was no extension of the disease from patients treated 1 1 
 in the cities the epidemic could only spread where the proper mos- 
 quito chanced to be present. The introduction of the mosquito alone 
 can have no ill effect unless it has previouslv bitten yellow fever pa- 
 tients, and in like manner, sufferers from yellow fever are absolut ely 
 harmless to others unless they are bitten by the proper mosquit o. 
 
 As Dr. Howard, no doubt, told you last year, the female mosquito 
 at certain periods in her existence experiences a physiologic need 
 for blood. The hemoglobin of the blood seems necessary for the 
 maturation of her ovums, and she will not deposit her eggs until she 
 has obtained a meal of blood. The male insect can not transmit 
 yellow fever, because, having no need for it, he never sucks blood. 
 and while his proboscis will provide him with fruit juices, it will not 
 penetrate the animal skin. The mysterious movement s of the disease, 
 passing from house to house, even at times when there had been no 
 communication between the inhabitants; the remarkable immunity 
 enjoyed by some groups of persons who were equally and full 
 orach exposed as others who were decimated by its ravages; t 
 as well as the peculiar way hi which the infection clung to dwell 
 and ships, invested it with a mystery that puzzled physician 
 centuries, and remained totally unexplained until the demonstration 
 of the mosquito theory within the past five years. Even to-d,, 
 our own country, where the results upon which it is based were first 
 
YELLOW FEVER. 197 
 
 published, the mosquito theory of the transmission of yellow fever 
 still has many opponents, and some of its supposed friends are very 
 weak-kneed and seem still to be looking -for evidence that would 
 justify them in deserting it. It is painful to read, in one of our most 
 prominent and influential daily newspapers, the letters emanating 
 from a well-known writer upon the subject of yellow fever, who a 
 few years ago was looked up to as an authority and wrote for 
 standard professional works, but who is now damaging his own 
 reputation and retarding progress by asserting that the mosquito is 
 not the sole medium for the transmission of this disease. It does not 
 seem to have occurred to this widely known and most interesting 
 writer that the burden of proof rests upon him, and that he should 
 either remain silent or be prepared to prove by actual demonstration 
 that there is some foundation for his claim. I take the liberty here 
 to suggest to the paper in whose interest this writer was sent to Cuba, 
 that it could hardly invest a few hundred dollars more profitably than 
 to enable this gentleman to furnish the necessary evidence in support 
 of his statements, if such evidence is obtainable, as it certainly should 
 be if his assertions are well founded. Who would think to-day of 1 
 advancing the old theory that malarial infection is contracted in any 
 other way than through the bite of the mosquito ? No one who is 
 familiar with modern ideas on parasitology would entertain the idea 
 for a moment, and there is no more ground for assuming that yellow 
 fever is transmitted in any other way than there was formerly for 
 entertaining that opinion in regard to malaria. In your own State 
 during the last two years you have had abundant evidence of the 
 power of measures, based upon the mosquito theory alone, to suppress 
 this disease, even when that theory met only half-hearted acceptance. \ 
 Do not understand me as intending to reproach those hesitating 
 nonbelievers who were so slow to move ; on the contrary, I sympathize 
 with them and with their refusal to conform their ideas to all the 
 new theories that were being constantly advanced, then denied, con- 
 tested, and recontested with every reappearance of the disease. 
 
 But let us return again to the scenes enacted, and the conditions 
 found, where the disease has prevailed in the past. Dr. O'Halloran, 
 in summing up after studying the epidemic at Barcelona, calls atten- 
 tion to the House of Charity, a clean, well-ventilated building in the 
 noninfected part of the city, and which was occupied by more than 
 1,100 persons during the height of the epidemic. These persons, men, 
 women, and children, went out daily into various parts of the city, 
 some visited the sick and entered the houses of the dying and the 
 dead. Among all this number, only 2 contracted the disease. These 
 were treated in theSeminario Hospital, where 1 recovered and the other 
 died. The one that recovered was at once returned to the House of 
 Charity, where she mingled with the other inmates ; still none of them 
 was affected. He then says: 
 
 The foregoing is a true report, and may be regarded as an important one. Had the 
 House of Charity been situated in the eastern extremity of Barcelona, or in Barceloneta, 
 where the epidemic cause existed to a high degree, the destruction would have been 
 in all probability great; but as the cause did not extend, or only in a very inferior 
 degree, to that part of the city in which the House of Charity stands, the cause of the 
 nonpropagation of the malady is easily accounted for. This case strongly tends to 
 prove that the yellow fever will not multiply except where an epidemic cause exists 
 in force; and it moreover proved that the disease is not contagious. 
 
198 \TP.. 
 
 Further on. in speaking of the Ca-a Miserecordiji. or House of Vity. 
 he states: 
 
 The building is low, but the apartments are spacious and well ventilated. It con- 
 tained 150 girls during the rage ot the epidemic. The nuns who i< :K h them are _' i in 
 numl - maintain themselves by washing, ironing. and other similar modes 
 
 of occupation. They employ women to traverse the city from house to house to ]>n> 
 cure needlework, etc. These women went to all parts of the city; they communJ 
 indiscriminately with the inhabitants, and they were not affected by the disea.^ 
 did the nuns or girls suffer by communicating with them. This is a singular fact, and 
 a strong one. 1 1 appears strange that a disease which was said t.> ha\e I.een im; 
 from Habana into Barcelona, from Barcelona to Intosa, and from thence to 
 .inenza, Malaga. etc., c>nld n<t be introduced into the House of I'ity th 
 numerous channels of communication. 
 
 Again, speaking of the House of Correction, a thiee-Mory >tnr 
 building. in which were located 100 females during the epidemic 
 season, lie asserts: 
 
 Nine of them were attacked with the reigning malady; 4 of them had been recently 
 admitted as having committed some irregularity in rickly Barreloneta. Tin-;. 
 all removed to the Seminario Hospital, where -1 died; the remaining '. when cured, 
 returned to the House of Correction; they communicated freely with the other 
 no disease ensued. This house was visited daily by some of the female inhabit. 
 the city, who, through charity, brought eatables, etc., but without detriment to the 
 inmates. 
 
 Hao! this been a contagious malady, the persons who r< 'turned to 
 the House of Correction after being cured in the Seminario Hospital. 
 which was then the seat of pestilence and of death, and to which 
 hundreds were sent to die, eould scarcely have failed of communi- 
 cating the disease to the numerous females who had intercourse with 
 them at all hours of the clay. 
 
 Of 50 persons who were constantly employed burying the dead. 
 only 2 died, although they communicated freely with the inhabitants 
 of the city in the nighttime. 
 
 Later he mentions the lazaretto called Marine, a mile to the east of 
 Barcelona and within 150 yards of the sea. It was opened for the 
 si< k on August 7; 79 sick were admitted, of whom 58 died : :>J net 
 were employed in various duties of the establishment as doctors, 
 friars, servants, and washerwomen, and not one of them took the 
 disease. Of the above number, 6 were employed in burying the 
 dead, and 3 in washing the bedding. After this establishment was 
 broken up, 5 women remained in it, employed in washing the bedding 
 of the Seminario Hospital, but without being affected by the disease. 
 
 In his conclusions, he finally observes in discussing the epidemic : 
 
 Its fatal and malignant nature in unventilated places; the exemption of parts i the 
 city from its influence, when no precautions were taken; the M< kenin.u of persons 
 who observed the strictest seclusion; the sudden impression of contaminated air on 
 persons recently from the country, without communication with the inhabitants of 
 the city; the greater exemption of nurses and other attendants on the sick from the 
 disease, than those who were simply exposed to the contaminated air of sickly houses; 
 the almost absolute exemption of washers of bedding, clothes, etc., which had recent 1 y 
 been used by the sick; the circumstance of the attendants in the hospitals and laza- 
 rettos having generally escaped the impression of the malady; the impossibility <-f 
 diffusing the disease in the country, where no epidemic cause existed; and, finally, 
 eath 
 
 the death of some hundreds of persons who communicated with Ban . i 
 
 sickened in the neighboring villages and country houses without a solitary in 
 of its affecting the most assiduous of its attendants, however circumstanced, are ascer- 
 tained facts and convincing proofs of the noncontagious nature of the yellow fever. 
 
 The evidence that Dr. O'llalloran offers in support of his coin 
 tion that yellow fever is not contagious is most ronelusiv. After 
 
YELLOW FEVER. 199 
 
 reciting the appearances found upon dissecting the bodies of those 
 who had died of the disease, he publishes a letter written by Dr. 
 Salvador Campmany during the following year. Dr. Campmany was 
 in charge of the Virreina Hospital at Barcelona during the outbreak 
 of 1821, when, between September 1 and December 20, this hospital 
 handled the bodies of no less than 8,649 persons dead of yellow fever. 
 O'Halloran states that Dr. Campmany was at first of the belief that 
 the disease was contagious, and when he began to take care of the 
 sick he wore an oilcloth dress. The letter is so interesting that I 
 shall give you the last paragraph verbatim. 
 
 The above sketch does not afford grounds for argument as to the contagious or non- 
 contagious nature of the disease. I shall only state that out of 30 persons of all descrip- 
 tions who were destined to assist the sick not one took the disorder. The nurses con- 
 tinually communicated with the sick. When delirious patients escaped from their 
 beds the assistants had to take them on their shoulders and replace them in their 
 respective quarters. On the opening of the bodies the anatomists, in my presence, 
 involuntarily cut their fingers and hands, and not one was inoculated with the yellow 
 fever. When the gravediggers carried the dead bodies to the church yard they had to 
 handle them a great deal before throwing them into the pit, and not one suffered in 
 his health. In short, not an individual employed in the lazaretto either took the 
 disorder or was infected by those who were sick of the yellow fever. 
 
 One could scarcely desire more complete confirmation than this of 
 the subsequent demonstration, almost 60 years later, by the army 
 board, of the noninfectiousness of the clothing, bedding, and dejecta 
 of yellow fever patients. 
 
 These were the opinions in 1823 of an observer who had seen and 
 himself suffered from yellow fever in the West Indies some years 
 before. Others, however, who were equally qualified to observe, 
 insisted, and advanced evidence to show, that the disease was 
 imported and that it was contagious. In short, the same differences 
 of opinion and the same dissensions among the highest authorities in 
 regard to this disease prevailed then as before and since, even to the 
 present day. O'Halloran states that the disease was not declared to 
 be the American yellow fever until August 14, 1821; that in April a 
 fleet of 52 vessels sailed from Habana for various Spanish ports, 20 of 
 them for Barcelona. Cases of yellow fever occurred on some of these 
 vessels after their arrival in Spain, but for commercial reasons every 
 effort was made to conceal them and deny their real nature. Many 
 of the sailors on the infected vessels were, of course, immune, and of 
 those who were susceptible the larger number had suffered attacks 
 during the voyage, so that while they were lying in the Spanish har- 
 bors the first persons to become infected were those who visited the 
 ships for the purpose of unloading, making repairs, etc. Some of 
 these vessels lay at Barcelona early in June, and we are told that 
 during this month "the bilious remittent or gastric fever was common, 
 and ultimately predominated in so high a degree as in a manner to 
 supersede all other diseases; and that during the month of July the 
 bilious remittent fever, with hemorrhagic affection, was common and 
 obstinate." The following sentence, quoted verbatim, is of much 
 interest to us at present : 
 
 It is worthy of remark that during this month (July) the flies and mosquitoes were 
 infinitely multiplied. 
 
 How well this reminds us that the same unusual prevalence of 
 mosquitoes during an epidemic of yellow fever has been noted by a 
 number of American physicians, including Dr. Rush, at Philadelphia, 
 
200 
 
 in 1797 and 1805; Dr. Vaughan, at Wilmington. 1VL. in 1802; Or. 
 Weightmann, at St. Aui:iistine. Kla.. in ls:;<i; Dr. \Yood. at (Vnter- 
 ville, and Dr. Beyrenheiat, at Hil>\i. Mi>^.. as well as Dr. Barton, at 
 Clinton, La., an.l hr. Ho\\ler, at New Orleans, all in is">:>. \\'hat 
 interest these ol)-n-\ at ions add to the now well-known mosquito 
 theory of tlu' u ..n of the disease, and how well do modern 
 
 neiices and knowledge add confirmation to Sydenham's theory 
 that certain diseases resulted from an ' 'epidemic constitution of the 
 atmosphere. " 
 
 1 would like here to call your attention to some statements made 
 by a well-known Galveston physician in 1876. I>r. ( Ireensvillf 
 ifewell, at that time a member of the Galveston Medical Society and 
 professor of surgery in the Texas Medical College, wrote of yellow 
 fever, of which he was a wonderfully close student, as folio v. 
 
 Its history shows that no ship, however filthy, can develop it while it n mains out 
 of its endemic or epidemic influence. No heat or moisture can alone pro 
 we would have it as often in the East Indies as in the West Indies, an<l if tin- 
 in the East Indies were the same as in the West Indies it would be intr<><! . 
 as well as in the Y\ -; Indies, by ships. Hence there must be some cause, 8]< 
 and sui generis, that produces it. This cause, I have assumed, is animalcular or fun- 
 gptic, and partakes of the nature of the grasshoppers of Egypt and the western prai- 
 ries, or the smut in cereals; but these are too small to be observed with any instruments 
 we now have, and have so far eluded demonstration; but if we compare the eff< < 
 heat and cold on gnats and mosquitos with yellow fever, it will not bo dilli. uli to 
 believe it is of the same nature, as it is controlled by the same natural laws. 1 
 
 So far as I know, Dr. Greensyille Dowell was the first even indi- 
 rectly to incriminate the mosquito by pointing out the fact that it 
 is governed by the same natural laws as yellow fever. And live 
 years after, in 1881, Dr. Finlay enunciated his theory that the dis- 
 ease was transmitted by the mosquito, but his theory was not pr 
 until 19 years later. 
 
 O'Halloran's observation that bilious remittent fevers prevailed for 
 two months prior to the appearance of yellow fever has been dupli- 
 cated in the United States hundreds of times, and we are forced to the 
 conclusion that there must be some relationship between bilious remit- 
 tent and yellow fever. O'Halloran thought tnat these bilious remit- 
 tent fevers were of local origin and that they gradually merged int<> 
 yellow fever. The same opinion has been held by many in our .\vn 
 country, but this has been offset by evidence, on the other hand, that 
 bilious remittent fever was undoubtedly imported from the Tropies, 
 and was simply a milder form of yellow fever. The truth is that 
 practically all such cases were genuine yellow fever that were not 
 recognized because of the absence of black vomit, which has been 
 erroneously regarded as a necessary symptom. In the work of the 
 Army commission 14 cases of experimental yellow fever were pro- 
 duced by means of the mosquito, and some of them were severe, hut 
 black vomit was not present in a single instance. This led some 
 persons to the conclusion that cases produced by only one or two 
 mosquitos were necessarily mild, hut the experience of Dr. (iuiteras 
 in August, 1901, proved the contrary. Out of seven cases that he 
 produced by the bites of one or two mosquitoes, three died with 
 black vomit. 
 
 I have purposely cited from Dr. O'Halloran's account of the epi- 
 demic at Barcelona in order to show that other careful observers, 
 
 i Yellow Fever and Malarial Diieases, by Oreensvllle Dowell, M. D. Philadelphia: 1876, p. 13. 
 
YELLOW FEVER. 201 
 
 working in other fields, have recorded the same observations and the 
 same opinions as the older American physicians. 
 
 The literature of yellow fever in the United States shows that in 
 nearly every outbreak a number of cases, usually the first ones to 
 occur, have escaped recognition. This has happened from the time 
 of Rush until to-day, and has been due to (1) the comparative mild- 
 ness of the cases, which led to the diagnosis of "bilious remittent 
 fever;" (2) the dread on the part of the physician attending these 
 cases to assume the responsibility for diagnosing the first case of 
 yellow fever, because, in the event that black vomit did not super- 
 vene, the correctness of the diagnosis would be called into question, 
 and the physician would be branded an enemy to the community. 
 The Eleventh Annual Report of the Florida State Board of Health, 
 published in 1900, furnishes an admirable illustration wherein it is 
 shown that in the outbreak at Key West in August, 1899, there were 
 already 11 cases unrecognized in the town before a single one was 
 correctly diagnosed. Is it any wonder, then, that under such cir- 
 cumstances the disease was able to gain a firm foothold ? The occur- 
 rence of a number of cases of the so-called " bilious remittent fever," 
 of short duration, should always excite suspicion, for such cases, 
 when found in groups, are almost invariably cases of genuine yellow 
 fever. At the present day nothing less than the absolute demonstra- 
 tion by an experienced observer of the presence in the blood of 
 malarial parasites or spirillums would justify any other diagnosis 
 than yellow fever; and even if they were shown to be cases of malarial 
 or relapsing fever, modern scientific medicine requires that, in the 
 case of the former at least, the patients should be rigidly protected 
 against the bites of mosquitoes, since we know that malaria, like 
 yellow fever, can be transmitted in no other way than through the 
 bite of that insect, if we except experimental inoculation. In the case 
 of relapsing fever, of the manner of transmission of which we know 
 absolutely nothing, it would be wise to take the same precaution. 
 
 The epidemics that have ravaged the city of Philadelphia have 
 been so graphically described by Rush and later by La Roche that 
 one is apt to conclude that the only serious outbreaks this country 
 has experienced were those occurring at Philadelphia, New Orleans, 
 and one or two other seaports. It is only when we search the litera- 
 ture of this disease, that we can appreciate the general devastation 
 and terror created by it, and the enormous losses sustained by the 
 communities it has visited. In a treatise on yellow fever by Dr. 
 Samuel Brown, of Boston, which was published in 1800, he says in 
 speaking of the disease : "This is a foe against which neither ramparts 
 nor intrenchments afford any security: 'It wasteth at noonday;' and 
 every principal town throughout the United States exhibits recent 
 and mournful testimonials of its ravages. We will not enter upon a 
 particular detail of the distresses which Philadelphia, New York, 
 Boston, and other commercial places have experienced; the tale of 
 woe would be too afflictive for even the dullest sensibility to bear 
 and the feelings of humanity would be agonized to overexcitement." 
 
 In order to show the manner in which yellow fever invades a sea- 
 port town, and the mystery attendant upon its appearance and 
 spread, I will quote from the report of the committee of medioal men 
 appointed to investigate the outbreak that occurred at Mobile, Ala., 
 in 1819. After giving in detail the condition of the wharves and 
 
202 DW WW1 K. 
 
 docks, the direction of tlu- prevailing winds, and the dourer of tem- 
 perature and moi>ture. they state that during the previous winter, 
 spring, and summer up to .Inly 1. the city was healthy. In the 
 latter part of July a number it eases of bilious fever occurred 
 
 among persons unaccustomed to the climate, and some of a more 
 (|ue>tionahle character; several persons employed as workmen in 
 filling up one of the new wharves were taken violently ill. and 
 after a short illne of two or three days. About the same time t\vo 
 
 usually employed ahout Daimhin Street Wharf we: 
 m like manner, and died after a short illness. A number of carpel 
 and sailors employed about the wharf, and who were much on 1 
 the schooner Sally, filled with stagnant water, and about the steam 
 sawmill, where there was a pond of like offensive water. 
 with violent fevers, and several of them died. The ph; who 
 
 attended these persons died, but it is stated that one of them. Dr. 
 Lawton, spoke of them as cases of malignant fever. An engineer 
 at work on a steamboat at the same wharf died soon after. hU (lineal 
 lasting 5 days. A man who attended him. and a servant boy living 
 in the same house, were taken down with a similar fever, and died 
 on the third and fourth days. All these persons died with Mack 
 vomit, and were declared by the attending physicians to be cas. 
 yellow fever. At about the same time otner fatal cases occurred 
 among persons whose time was spent about the ri\ er and wi 
 stores in that neighborhood. Within a few days after the prevail 
 of yellow fever was known an exodus took place, and the population 
 became reduced from 1,300 in July to 500. Of these, 133, or over 
 25 per cent, died/' 
 
 The report states that the suburbs of the town, at no greater dis- 
 tance than a mile from the river, were as healthy during the prevalem-e 
 of the fever as more distant parts of the country; and the disease was 
 not known to be communicated, in any instance, to persons out of the 
 town by the removal of and attendance upon the sick. Hence, it was 
 concluded that the disease was only communicable in the atmosphere 
 in which it originated, and even then some other cause, not under- 
 stood, appeared to be necessary, because "a number of persons fre- 
 quently in the room with the sick, dying, and dead, in circum^ta 
 of the greatest exposure, never took the fever." It is further rem;i 
 that Natchez ana other ports on the Mississippi below suffered heavily, 
 and practically every seaport on the Atlantic and Gulf coasts npp< 
 to have suffered more or less that summer from yellow fever. It is 
 very interesting to note how the disease almost invariably first made 
 ;>pearance in the vicinity <! wharves and shipping, in parts of the 
 town where surface drainage is usually more or less detective, and 
 decaying wood and vegetable refuse are necessarily present . 
 were* the only special conditions found to prevail m these localit i. 
 was quite generally conceded that to them t he disease owed its on 
 When vessels with yellow fever on board arrived in p>rt, ell- 
 made to conceal the nature of the disease, and by fa. hen 
 patient < were buried at sea, or by burial at night where death occurred 
 m port, many cases are known to have been concealed. Again, a 
 vessel with an immune crew, but infected mosquitoes on board, would 
 infect* persons from shore who visited the ship for various purposes, 
 yet, there being no sickness on the vessel, she \\a- relieved of su-pi 
 and the disease was assumed to be of local origin. Cases resembling 
 
YELLOW FEVER. 203 
 
 yellow fever, but without black vomit, were called bilious fever, and 
 under this guise, aided by the occasional concealment of an undoubted 
 case, the disease frequently escaped detection for weeks and months. 
 
 In the description of the epidemic at Baltimore, also in 1819, as 
 observed by various practicing physicians, we find many statements 
 that must now be regarded with special interest. For instance, it was 
 conceded by all that the first cases appeared at Fell's Point, where the 
 principal docks and wharves were located. One observer states that 
 the disease never originated more than two or three hundred yards 
 from the water, and it was six weeks from the commencement before 
 the disease had spread much more than 100 yards from the place of 
 origin. The transmission of the contagion was rightfully attributed 
 to some unknown agent present in the atmosphere, for in speaking of 
 the infection it is said, "upon this ground, then, it may be asserted that 
 some matter which was foreign to the natural composition in the air 
 of this place floated about with it at this time. Some portion of 
 whatever this air contained was therefore of necessity breathed or 
 swallowed by the people who came within its limits. And the 
 properties of the foreign matter in this air must be decided upon by 
 the effects which it has had on those who receive it into their habits.'' 
 We have only to add the mosquito now, and the general truth of the 
 above statements becomes manifest. And with the mosquito we 
 necessarily include the insect's bite as an additional and at that time 
 unknown avenue of entrance for disease. Conceding this, how easily 
 one can explain the first appearance and prevalence of the disease in 
 the localities where the conditions are favorable for the multiplication 
 of mosquitoes, viz, in the low-lying and generally poorly drained 
 districts in the vicinity of the wharves and shipping. When we con- 
 sider further that the mosquito that transmits yellow fever is a tropic 
 and subtropic insect and that, practically speaking, it is not found 
 north of Mason and Dixon's line, it then becomes absolutely clear that 
 yellow fever in epidemic form can be introduced into that section 
 only when the presence of high atmospheric temperature and moisture 
 afford conditions favorable for the propagation of this insect. But 
 the yellow-fever mosquito is a tropic insect, and yellow fever is a tropic 
 disease; it follows, therefore, that, given the proper conditions as to 
 temperature and moisture, there must have been introduced at that 
 time both the proper insect and cases of the disease. These must 
 necessarily have come originally from infected localities within or near 
 the Tropics. 
 
 In the days when yellow fever prevailed in our northern seaports 
 outbreaks invariably followed the arrival of one or more vessels 
 from Habana or some other infected port, but the interval elapsing 
 between the entry of the vessel and the recognition of the disease 
 was so long and the manner of extension of the disease was so mys- 
 terious that it became impossible to trace the connection between the 
 one and the other. Let us suppose, for example, in the month of 
 July, at a time when yellow fever prevailed and before the days of 
 rigid quarantine, a sailing vessel lying at Habana and bound for 
 Baltimore. She is tied up at a dock, and numbers of the yellow- 
 fever mosquitoes, which are the prevailing house mosquito at Habana, 
 fly aboard. They deposit their eggs in open casks, pitchers, or other 
 receptacles containing fresh water exposed to the air. The crew are 
 immune with one exception, and this man is taken sick three or four 
 
204 YELLuu 
 
 da\> uut from Habana on the journey northward. He has yellow 
 fever, but his temperature is only moderately High, ami although 
 he is deeply jaundiced there is no black vomit. The captain ii 
 the case is one of bilious remittent fever and not yellow fever. \ 
 onecould quest ion his statement . because even the best physicians \\ere 
 unable at that time to draw the line between yellow fever and malarial 
 fever, and it is not always easy to do it to-day. The hypothei i 
 genuine though unrecognized yell i- hit ten by a iiumherMf tnoa- 
 
 qmtoes during the first t hree days of his fever, bu1 DO one is aware of ii. 
 MP \\Miild attach any importance to it if they knew. In two weeks 
 the patient is practically well, and in another week >r t WM the \ 
 arrives in port with a clean bill of health. There i- no sickne 
 board, she is in fairly good condition, and ties up to the dock in 
 Baltimore say 25 or 30 days after leaving Habana, and with several 
 infected mosquitoes on board. 
 
 Perhaps these mosquitoes are disturbed by the unloading Mf 
 the ship or cleaning of the cabins, and they may lly onto another 
 ship tied up at the same wharf or travel along the wharf to a watch- 
 man's house or some other dwelling in the immediate vicinity. The 
 first cases of the outbreak may appear on the other ship tied up at 
 the dock, and this latter vessel may have come from Kui-Mpe and 
 be in rather foul condition. The infection in that case would he 
 attributed to the foul air generated by the action of a hot atmosphere 
 upon the decomposing matter present in her hold. The next 
 may appear in some one sleeping or employed on the dock nr MM a 
 neighboring vessel. In the month of August conditions would he 
 favorable for the propagation of mosquitoes, and in addition to those 
 hatched out on the trip from Habana another brood will soon have 
 appeared on shore. Tne mosquito may also have been introduced 
 by other vessels earlier in the season, and the conditions "\\ill then 
 be suitable for a further extension. The continuance of the out- 
 break necessarily depends on the coming together of the imported 
 mosquitoes and cases of yellow fever in the first three days of the 
 disease; consequently in numerous instances only one or two 
 occur, and none follows unless fresh cases are introduced by other 
 vessels from infected ports. The frequency of the occurrence 
 cases of bilious remittent fever in American ports during the la-t 
 century shows that during the early part at least yellmv fever waa 
 being constantly imported, though it onlv occasionally assumed 
 epidemic proportions. Let us suppose that the vessel lea vim: 1 lahana 
 sailed for New Orleans, Mobile, or Galyeston, instead of Baltim<n >. 
 Here the case will be different, because in these places the condit ion- 
 are favorable for the propagation of the vellow-fever mojuito 
 throughout the greater part of the year, and the introduction 
 single case might prove sufficient to fight up an epidemic. l>< < -au-e t he 
 proper mosquito is at nearly all times present in the house- m ahun- 
 dance. Frequent severe outbreaks have occurred at New Or lean- 
 until a large part of the population had become immune, and tin.., 
 were nonimmunes and could afford it habitually left the city 
 during the warm season. Among the few who remained and chanced 
 to be bitten by the proper infected mosquitoes, cases would occur 
 from time to time as bilious fever, often suspected to be yellow 
 fever, hut for reasons of policy thev were not so reported. Finally. 
 after a few years had passed, confidence would be restored, and u 
 
YELLOW FEVER. 205 
 
 larger proportion of nonimmunes would supply the material for a 
 fresh outbreak, which was certain to appear sooner or later. Then 
 came a sudden exodus, with the wrecking of commercial interests, 
 neglect of the sick, and the untold suffering known only to those who 
 have passed through a severe epidemic. Here let me remark with 
 emphasis that for the production of an outbreak of yellow fever 
 three factors are necessary: (1) Preexisting cases of the disease, 
 (2) mosquitoes of the genus Stegomyia, and (3) nonimmunes or per- 
 sons who are susceptible to the disease. I would impress upon you 
 the fact that the absence of any one of these factors will render it 
 absolutely impossible for an outbreak to occur. An epidemic of 
 yellow fever is impossible in the absence of preexisting cases, for the 
 disease can not be generated by any amount of filth, heat, moisture, 
 or decomposition without the intervention of the three factors 
 named. Excluding experimental inoculation, the occurrence of 
 cases of yellow fever is not possible under any conditions without the 
 presence of the proper mosquito to transmit the infection from the 
 sick to the well. And, finally, given any possible local conditions, 
 any number of cases of yellow fever and any number of infected 
 mosquitoes, in the absence of susceptible persons, cases of the disease 
 must disappear. 
 
 But I am going faster than I ought. Here in Galveston you 
 are in the epidemic zone of the disease; you have had your epi- 
 demics, and you have reason to guard against them in the future. 
 Your city was described 30 years ago as being built upon an island 
 composed of shingle, and this shingle so saturated with water that 
 the latter could be found at a depth of a few inches. The mean 
 temperature is about 74, and the rainfalls are usually heavy in 
 April, May, and June. Owing to the saturation of the deeper layers 
 of the soil, the rain water lay upon the surface in pools until it disap- 
 peared by evaporation in the dryer months of the late summer and 
 autumn. The surface pools of fresh water were ideal breeding places 
 for mosquitoes, as also were the receptacles for rain water, which the 
 early inhabitants collected and used after the custom at New Orleans. 
 Yellow fever paid its first notable visit here in 1839, only a few years 
 after the establishment of the first settlement. The population was 
 about 1,000, and the people were located mostly along the Strand, 
 in close proximity to the wharves and vessels. The first case reported 
 occurred late in September on a steamer recently arrived from New 
 Orleans. At about the same time another case occurred on a vessel 
 anchored only a few yards from her. Both cases were fatal. As 
 others were reported on land at the same time, it is more than likelv 
 that these were not the first cases, but as they were the first in which 
 black vomit appeared they were probably the first in which a diag- 
 nosis of yellow fever could no longer be withheld. In this epidemic, 
 which lasted less than two months, we are told that there were 250 
 deaths, which means the occurrence of at least twice as many cases 
 among the population of 1,000 persons. It is further stated that the 
 epidemic died out because " every unacclimated person had either 
 fled from the town or suffered an attack. This was proved by the 
 fact that when the refugees began to return the disease broke out 
 again among the newly arrived, and there were a number of deaths." 
 How beautifully this all fits in with the mosquito theory, now that 
 we know that the bite of the mosquito can convey the disease as long 
 
206 U>W FEVER. 
 
 as two months after it has bitten a v el low fever patient. I have 
 good reason to be a firm believer in the theory of the transmission of 
 the disease by the mosauito, for I have seen i<> cases of experimental 
 yellow fever 'produced bv the application of infected insects, and it 
 was my good fortune to be the first case amonir them. AmoiiLT other 
 experiments it was my privilege to apply two mox,|uitoes of the 
 proper genus (Steiromyia) to a patient Buffering with yellow fc\ er. 
 and 57 days later 1 applied the same mosijuitor <>lun- 
 
 teer, who had been kept in strict piarantine for 7S days. In four days 
 he \\as taken ill with a typic attack of yellow fever, from which he 
 made a good recovery. 
 
 Returning to the subject of Galveston. a few cases are said t 
 have appeared in IS-pJ. but in 1MI a violent outbreak raged for 
 about six weeks, and then erased suddenly from the absence of 
 ceptible persons. Here it was again noticed, however, that mm 
 immunes who visited the town but once for the purpose of shopping. 
 etc., occasionally returned home to be taken ill with yellow fe\ 
 few days later. This continued until the appearance of a white frost. 
 which we know benumbs the mosquito and forces it to go into hiber- 
 nation. This, therefore, affords a rational explanation of tin 4 e 
 of the first sharp frost, which has so long been welcomed as the 
 savior of districts afflicted with yellow fever. During the epidemic 
 just mentioned nearly 400 deaths occurred in a population of about 
 4,000. 
 
 Three years later, in 1847, an epidemic was declared to be present 
 in the month of October and there were about 200 deaths in a popu- 
 lation of 4,800. In 1853, after an immunity of six years, the aeaths 
 from yellow fever were 535; in 1854, 404; in 1858, 873; and in 1859, 
 183 in a population of about 10,000. 
 
 In September, 1864, the disease was again epidemic, the deaths 
 being 259 and the population 5,500. Three years of exemption fol- 
 lowed, and in 1867 a severe epidemic is estimated to have produced 
 8,000 cases and 1,150 deaths in Galveston in a population of 15,000. 
 From Galveston it was carried to a number of smaller towns, among 
 which Alleytown on the Colorado River was afflicted with 200 deal hs 
 and about 800 cases in a population of 1,500. 
 
 During the same season Indianola is said t<> have received the 
 infection from Vera Cruz, and we are told that ''in less than a \\eek 
 the whole business part of the town was struck down as by li<rhtninir. 
 there being no less than 125 to 150 cases taken durinir that time out 
 of a population of less than 1,000." The extension of the disease 
 was checked by a rapid depopulation of the town. The number 
 of deaths amonir the citizens was about 75. From Indianola the 
 disease is said to have been carried to various points throughout 
 the State and even beyond. In 1870 and 1873 a few cases occurred. 
 but the disease did not assume epidemic form. There is reason to 
 believe, also, from the report of Dr. 1 1. A. West .of thi- city (Galveston , 
 that there were a few mild case- in 1x97. I can find no record of 
 any outbreak in Galveston since that time, although two cases ^< re 
 introduced on December 31 last, but as you well know there were 
 in the State of Texas in 1903 over 1,200 cases of yellow fever, with 
 nearly 140 deaths. Over 1,000 cases and 107 deaths are recorded 
 for I. lone, and if it were not for the cner^'tic mca-ures insti- 
 
 tuted against the fnosquito there would undoubtedly have been 
 
YELLOW FEVER. 207 
 
 another fearful epidemic to record for the United States similar 
 to that of 1878, during which, according to the Board of Experts 
 appointed by Congress, more than 100,000 persons were stricken 
 in their homes, and 20,000 lives were sacrificed in a single season. 
 In Memphis alone, according to Keating, there were in 1878, 17,600 
 cases of yellow fever, with 5,150 deaths, a mortality rate of about 
 1 in 4 of the reduced population. Scenes were enacted there similar 
 to those described by Rush in his account of the epidemic at Phila- 
 delphia almost a century before, when the streets became deserted, 
 bodies remained unburied, friends no longer shook hands upon 
 meeting, husbands deserted their wives, wives their husbands, and 
 parents their children. So, in Memphis, we are told of a prominent 
 man who fled the city and refused to return when his wife and chil- 
 dren were stricken and who still remained 50 iniles away when notified 
 of their death. These deplorable incidents, however, were more 
 than offset by numberless instances of heroic devotion on the part 
 of Sisters of Charity, nurses, and physicians who died at their posts 
 of duty. As one illustration I might cite from the little book on 
 yellow fever published in 1898 by Dr. W. L. Coleman, of Houston. 
 Dr. Coleman was present during the Memphis epidemic and took 
 down the names of 45 volunteer physicians immediately after their 
 arrival. Most of them came from the Northwest, and one did not 
 remain. The others all contracted yellow fever and 30 of them were 
 dead within a month. 
 
 At that time no one could say how the disease was contracted; 
 some held that it was of local origin and contagious, others that it 
 was not contagious; many believed it was imported, that it was 
 infectious but not contagious, and was carried in some mysterious 
 way by the atmosphere. We are told by Keating that "Dr. Dowell, 
 of Galveston, says that in 19 cases put of 20 it will be found to have 
 been introduced or imported/' which was wonderfully near to the 
 truth as we know it to-day. 
 
 It may surprise you to learn that yellow fever experimental 
 inoculations began in the United States in Philadelphia, during the 
 yellow-fever epidemics in the years 1802 and 1803. It is a fact that 
 in those years Stubbins Firth, a medical student of the University 
 of Pennsylvania, deliberately experimented upon himself by placing 
 Fresh black vomit and blood serum obtained from yellow-fever 
 patients into wounds made in his arms and legs. Failing in this, 
 tie inhaled the fumes from black vomit, which he heated over a sand 
 bath in a small room, and then, making the residue into pills, he 
 swallowed them. He administered black vomit to animals, injected 
 it into their circulation, and deposited it in their tissues. As the 
 results of these and other experiments were negative, he concluded 
 that yellow fever was neither infectious nor contagious, and reported 
 his work and conclusions in a graduation thesis in 1804. 
 
 But little more was done or could be clone until the advent of the 
 tiew science of bateriology encouraged the belief that this mvsterious 
 malady might be caused by a bacterium. The first to claim the 
 iiscoverv of the specific cause of yellow fever was Dr. Domingo Freire, 
 of Brazil, who went further than this, and claimed also that he had 
 conferred protection against the disease by inoculations with specially 
 treated cultures. He was followed by Dr. Carmone y Valle, of Mexico ; 
 Dr. Babes, of Brazil; Dr. Gibier, of Paris; and Dr. Finlay, of Habana, 
 
208 
 
 of whom believed that he had foiuul the cause of yellow fever 
 in a different organism. It remained for Dr. Sternheri: to show that 
 these investigators were all mistaken, and that the hacu-ria found 
 by them were not in any way related to the disease. Dr. Stemherj:. 
 himself, subsequently exhausted the iiM so far as the search for 
 bacteria was concerned; he also made e\tremel\ careful and thor- 
 ough examinations of the Mood and tissues obtained from patients 
 with yellow fever. He announced finally that his search had proved 
 unsuccessful, and his \\ork stands as the best that has ever been done 
 in the studv of the bacteriology of the disease. 
 
 In 1897 tne sensational announcement was made that D -ppe 
 
 Sanarolli, an Italian bacteriologist, working upon the island of Fl< 
 in Montevideo, had di-c. he cause of yellow fever in a bacillus 
 
 that he had found in about ">() ner cent of the patients examined bv 
 him. He reported also that the injection of pure cultures of this 
 bacillus into the circulation of dogs brought about an infection 
 similar to yellow fever in the human beinir. \\ith the vomiting and 
 other symptoms of that disease, and a similar condition of the or 
 after deatn. This announcement naturally interested Dr. Stern; 
 who at this tune had become Surgeon General of the Army, and he 
 immediately turned to an organism that he had obtained from about 
 50 per cent of the patients examined by him. that he had found to be 
 exceedingly virulent for the small laboratory animals, and which he 
 had called Bacillus X, because he had been unable positively t<> iden- 
 tify it. He obtained a culture that had been preserved by one of his 
 former assistants, and directed Dr. Reed and myself to undertake 
 certain experiments with it. As Dr. Sternberg had never injected it 
 into dogs, one of the first steps in our work was a duplication of some 
 of Dr. SanareUi's experiments, viz, to inject it into the circulation 
 of dogs. We obtained the same effects as Sanarelli had recorded for 
 his yellow-fever bacillus, and this seemed to indicate that the organ- 
 isms must be identical. Dr. Sternberg then procured a cult in 
 Sanarelli's bacillus from Prof . Roux, of raris. and handed it to us for 
 comparative study. It is amusing now to think of the fearful respect 
 with which we handled the culture from Dr. Sanarelli's la! 
 because we were fully prepared to accept it as the cause of yellow < 
 from what we knew of Dr. Sanarelli's reputation as a bacteriolo 
 After several months it became apparent that this supposed yellow- 
 fever bacillus of Sanarelli was nothing more nor less than the c >mm< >n 
 hog-cholera bacillus, an organism that was much better known in 
 America than abroad. Sanarelli was evidently at that time not 
 familiar with the bacillus of hog cholera, for he pronounced the irerm 
 obtained by him "the strangest >f all microbes that are known." A 
 bitter controversy arose upon the publication of our reports of the \\ork 
 hi which we had found that Dr. Sanarelli's bacillus wnen fed to young 
 hogs would produce the symptoms and lesions of hog cholera, [ndeeo, 
 Sanarelli still contends in his own country that he found the bacillus 
 of yellow fever, aeon tent ion that finds no support to-day amoiiL r repu- 
 table bacteriologists in this country or in Europe. 
 
 It is a remarkable fact that upon his own demonstrations alon- . Dr. 
 Sanarelli was awarded large pecuniary prizes and honors as tin- dis- 
 coverer of the causative agent of yellow fever. Unfortunately. 
 Archinard and Woodson, and a commission from the Marine-Hospital 
 Service, working in the United States, reported that their results con- 
 
YELLOW FEVER. 209 
 
 firmed the claims of Dr. Sanarelli. In 1897 and 1898, the latter com- 
 mission, consisting of Drs. Wasdin and Geddings, continued their 
 investigations in Habana, and in 1899 an elaborate report was issued, 
 in which it was claimed that dogs, rabbits, mice, and other animals 
 could be given yellow fever by infecting them with Sanarelli's bacil- 
 lus, that infection took place through the lungs, and that a diagnosis 
 of yellow fever could be made by isolating the bacillus from the blood 
 of the patient. This made matters rather interesting for us, but did 
 not shake our confidence in our results. Bacillus X (Sternberg) was 
 found to belong to the group of colon bacilli. 
 
 Finally, in 1900, during the American occupation of Cuba, yellow 
 fever became epidemic in Habana. To take advantage of the oppor- 
 tunity thus offered, Gen. Sternberg designated a board to meet at 
 Habana, for the purpose of continuing the study of that disease. The 
 members of that board were Drs. Walter Reed, James Carroll, Aris- 
 tides Agramonte (a Cuban immune), and Jesse W. Lazear. Drs. 
 Lazear and Agramonte were already at Habana, and we joined them 
 there in June. Our first aim was to confirm or disprove the claim for 
 Sanarelli's bacillus, which he had called B. icteroides, and after a most 
 painstaking and careful investigation of the blood obtained during 
 life from 18 undoubted cases of yellow fever, and of the blood and 
 tissues of 11 fatal cases after death, we were compelled to report that 
 we had failed to find Bacillus icteroides in a single instance. 
 
 Having thus disposed of B. icteroides, two lines of work now pre- 
 sented, one an investigation of the mosquito theory, so long advo- 
 cated by Dr. Carlos Finlay, of Habana, the other a study of the micro- 
 organisms present in the intestinal canal of yellow fever patients. The 
 former was chosen, because of the numerous points of resemblance 
 between yellow fever and malaria, which was known to be conveyed 
 by the mosquito. Both diseases are airborne; both are contracted 
 mostly at night; both jump from house to house in a mysterious way;, 
 both are noncontagious ; both prevail in the season when mosquitoes 
 are numerous, and infections cease to occur upon the appearance of 
 a sharp frost; the interval of time elapsing between the occurrence 
 of the first case and secondary ones in primarily infected dwellings 
 suggested the necessity for an intermediate host in the conveyance of 
 yellow fever; it was noted that in a large military command at Colum- 
 bia Barracks, near Habana, the only persons who contracted yellow fever 
 were those who left the camp after sundown, and these, after recov- 
 ery, although they mingled freely with their comrades, never infected 
 them. This latter observation seemed to show that the cause of the 
 disease was not present on the body, in the clothing, or the- dejecta. 
 A consideration of all these points led us to decide that the next step 
 should be to test the mosquito theory. In the early consideration 
 of this line of work the members of the board paid a visit to Dr. Finlay, 
 who received them most courteously, showed them the common house 
 mosquito that he believed to be responsible for the disease, narrated 
 the work that he had done, and kindly supplied them with some dried 
 mosquito eggs for the purpose of hatching them out for study. The 
 moral responsibility was next considered, and in a later conference it 
 was agreed that the members of the board would themselves be bitten, 
 and subject themselves to the same risk that necessity compelled 
 them to impose on others. 
 
 79965 S. Doc. 822, 61-3 14 
 
210 YELLOW FEVER. 
 
 Dr. Lazear was given charge of the mosquito \\ork. because ho 
 already had had experience with other mosquitoes. I was to con- 
 tinue my work with t ho cultures, and Dr. Reed returned to the Tinted 
 States. Dr. Lazear made a number of unsuccessful attempts with 
 mosquitoes, applied one or several davs after l>itinu r a patient as Dr. 
 Finlay had done, and he himself was bitten by a mosquito that he 
 had applied to a mild case of yellow fever K) days before. 1 reminded 
 Dr. Lazear that I was ready, and he at last applied to my arm an 
 insect that had bit ton a patient with a severe attack 12 'days pre- 
 viously. Four days later I had fever, and on the day follo\\inir 1 was 
 carried to the isolation camp as a patient with yellow fever. On the 
 day that my fever appeared, Dr. Lazear applied the same mosquito, 
 with throe others, to a soldier. X. V.. who \\as taken sick on the fifth 
 day following, and passed through a comparatively mild attack. 
 Scarcely more than a week later, Dr. Lazear was applying mos<|ur 
 as usual, late in the afternoon, to patients in the yellow fever hospital. 
 known as Las Animas. and while thus engaged a mosquito alighted 
 upon his hand. He allowed it to take its fill, and concluded it was 
 one of the common culex mosquitoes which were on-sent in the ho>- 
 pital in large numbers. So little importance did he attach to the 
 incident that he made no note of it, and related the circumstaii' 
 me when he was first taken sick, five days afterward. A week from 
 that date he died, having been delirious and affec {pfl with hlnr.fc yomit 
 for several davs. Thus ended the first set of experiments, with The 
 death of our esteemed and unfortunate colleague. 
 
 Two months later a new series of experiments was instituted for 
 the purpose of confirming the results already obtained, to see. also, 
 whether the disease could be contracted from exposure to soiled or 
 contaminated articles of bedding, clothing, etc., and to dot ermine 
 whether or not the infectious agent was present in the blood. 
 
 For the first-mentioned experiments an isolation camp, called 
 after our deceased comrade Camp Lazear," was established in a 
 secluded spot about a mile from Columbia Barracks and apart from 
 any habitation. In this camp there were placed three immunes and 
 nine nonimmunes, including one immune and one nonLmmuno phy- 
 sician. A strict Quarantine was maintained and only the immunes 
 were permitted to leave the camp. If a nonimmuno left, he was not 
 permitted to return. As newly arrived nonimmune Spanish immi- 
 grants could be obtained from the immigrant station at llabana they 
 were brought out and added to the command in quarantine. The 
 camp consisted of seven large hospital tents, separated by a wide 
 interval and pitched in the arc of a circle. The nonimmuncs dis- 
 tributed through the tents were required to sleep beneath mosquito 
 bars, and the rule was rigidly enforced. The plan was to pick out 
 men here and there in the Tine of tents, bring them down with infected 
 mosquitoes, and in that way establish the fact that cases could he 
 produced at will by the application of infected mosquitoes. It was 
 further desired to show that an infected house was simply one that 
 contained active infected mosquitoes, and that nothing more vrafl 
 necessary for the production of an epidemic in a susceptible commu- 
 nity. A new, tigntly ceiled frame building was constructed, 20 feet 
 by 14 feet, provided with two small windows, tightly closed with 
 fine-mesh wire screens; also with two vestibules protected \>\ 
 outer door, and an outer and an inner tightly fitting screen door, so as 
 
YELLOW FEVER. 211 
 
 to guard against the ingress of mosquitoes from without or their egress 
 from within. Upon entering the vestibule the screen door through 
 which one passed was closed, and the other was not opened until it 
 was made certain that no mosquitoes were passing in or out. The 
 lumber used in the building was tongued and grooved ; the walls were 
 battened on the outside and lined with white cotton cloth within. 
 The walls and floor were double, and all crevices were stopped; the 
 ceiling was covered with cloth and made so low that mosquitoes resting 
 upon it could be captured with ease. Across the middle of this room 
 there was built a wire-screen partition extending from floor to ceiling 
 and dividing it into two compartments, each with a separate entrance. 
 Beds were placed in each of these rooms, and one of them was 
 occupied by two nonimmunes for 18 consecutive nights. The bed- 
 ding and other articles admitted to the room were all disinfected. 
 On December 21, 1900, the date of the first occupation, 15 contam- 
 inated mosquitoes were turned loose in the unoccupied compartment, 
 and then a nonimmune entered and lay upon one of the beds, with his 
 chest and limbs exposed for 30 minutes. During this time he was 
 bitten by several insects and others bit him again later in the day, 
 when he lay there for 20 minutes. This procedure was repeated 
 again on the following day, the last of exposure. On December 25, 
 four days after his first exposure, this man who had remained in 
 strict quarantine, was taken ill with a severe attack of yellow fever, 
 from which he recovered. The other two men, who slept in the 
 same room but in another compartment, separated from the mos- 
 quitoes only by the screen partition, remained in their usual health. 
 Another building had been constructed similar to the above, but 
 provided with only a single vestibuled entrance. It was equally 
 protected against the entrance of mosquitoes and had two small 
 screen-protected windows provided with shutters, so as to exclude 
 sunlight as well as mosquitoes. It contained a coal-oil stove, by 
 means of which the temperature was kept above 90 during the day, 
 and the atmosphere was provided with moisture. Into this room, 
 which was warm, dark, and moist, like the hold of a ship in the Tropics, 
 several boxes containing sheets, blankets, pillow slips, and garments 
 direct from the yellow-fever hospital were placed. These had been 
 soiled intentionally with black vomit and other repulsive material 
 from cases of yellow fever. This room was then entered each evening 
 at sundown by two nonimmune Americans, one of them a physician, 
 who unpacked the boxes, handled and shook the articles, then hung 
 them up on nails in the walls, and retired for the night. Upon rising 
 in the morning they removed the articles from the walls, handled 
 them freely, and repacked them in the boxes, where they remained 
 until evening. This procedure of unpacking and repacking, handling, 
 and sleeping in the presence of the soiled materials was kept up for 
 20 consecutive nights, and in the meantime fresh supplies were added 
 as fast as they could be obtained. On one or two occasions the 
 stench drove the occupants out, but they returned again and slept 
 there. They spent the daytime in a tent nearby, but were strictly 
 quarantined. The pulse rate and temperature of all nonimmunes in 
 the camp were recorded three times daily, and showed that the health 
 of these men was not affected in the slightest degree; on the contrary, 
 they gained in weight. 
 
212 -l-OW FEVER. 
 
 These v. reeded \\ .nines after tho addition 
 
 of more soiled garments,* etc., and they in turn were followed by 
 another two for the same period. Some of these men slept between 
 the sheets and in the garments used and soiled bv yellow-l< 
 patients at the time of their death, and they even slept with their 
 faces upon towels sailed with blood that had been shown by 
 inoculation to be capable of infect ini: \vith yellow fever. In no 
 
 .ill any disturbance of health follow the- 
 
 the conclusion was therefore arrived at that vellow fever can not 
 be contracted through exposure to foinites. if one stops t> reflect 
 that the mosquito i^> not able to infect until U days or more after 
 contamination, one is forced to the conclusion that the yello\\-fe\ cr 
 parasite, which has never been seen, must, in all probability, 
 through a distinct cycle of development in the mosquito before the 
 insect becomes dangerous. As Dr. Howard has told you, 
 spending but slightly shorter interval is seen with the mosquito that 
 transmits malaria. The developmental phases of the ma I 
 
 Jarasitein the mosquito arc well known and have been demonstrated, 
 udging by analogy, therefore, it seems justifiable to assume that 
 the parasite of yellow fever appears also to belong t<> that <rroup of 
 obligate parasites whose whole existence is passed within the bodies 
 of two living hosts, one of which, man, is a vertebrate, and the other, 
 the mosquito, an invertebrate". This afTords an explanation of 
 uselessness of disinfection against yellow fever as well as ma I 
 and it also explains the instances occasionally noted in the literature, 
 where a prompt suppression of the disease followed the use of fm 
 tion as well as disinfection. 
 
 Returning to the subject of the experiments at Camp La/ear, the 
 susceptibility of the men exposed to the fomites or soiled 
 was shown by the fact that lour of them were subsequently ini< 
 by means of mosquitoes and blood injections. Four nonimmun 
 all were infected oy the subcutaneous injeetion of small quaii 
 of blood drawn in the first and second days of the di Thi> 
 
 established another point of analogy between yellow fever and mala- 
 ria, and demonstrated the presence of the infectious aircnt in the 
 blood, notwithstanding that we had failed to discover anything upon 
 careful microscopic examination of the blood from many patients, 
 including those in whom the blood, drawn at the same time, pro,: 
 yellow fever in persons into whom it was injected. 
 
 Nine additional cases were produced in Camp La/ear by the appli- 
 cation of infected mosquitoes, making in all 10 cases of yellow 
 brought about at will. All were taken sick within the u-ual p 
 of incubation, never more than six days. They were selected here 
 and there in the different tents, and no other 'cases occurred than 
 those purposely inoculated. As soon as a case appeared the patient 
 was immediately removed to the yellow fever isolation camp, a mile 
 distant, to avoid the possibility of any stray mo-quit. . uing 
 
 infected from him. In no instance was the mosquito found to be 
 capable of infecting in a shorter period than 12 days after biting the 
 patient, and one patient was infected with two mosquitoes kept as 
 long as 57 days. 
 
 This work was concluded by the end of February. I'M)], when 
 confirmatory ex peri meir taken up by Dr. John (iuiier.-. 
 
 Habana. His first patient was infected in February with a mosquito 
 
YELLOW FEVER. 213 
 
 obtained from the Army commission, and his subsequent inoculations 
 were unsuccessful until August, when he succeeded in infecting seven 
 persons with mosquitoes. Of these cases, three, unfortunately, 
 proved fatal. Among the latter was a young American nurse, Miss 
 Maas, of Baltimore, who voluntarily submitted herself to the experi- 
 ment. 
 
 In August, 1901, I returned to Habana, and obtaining some of 
 Dr. Guiteras's mosquitoes, infected two Spanish nonimmunes. 
 Drawing blood from one of them and separating the serum, I passed 
 the latter through a filter, which was shown to be capable of holding 
 back the ordinary bacteria. Injection of the filtered serum into two 
 Americans infected them with yellow fever. In this way it was 
 shown that bodies smaller than ordinary bacteria were capable of 
 producing yellow fever upon injection, and our failure to discover 
 anything upon microscopic examination of the blood of yellow fever 
 patients was thus satisfactorily explained. It was further shown, as 
 a point of great scientific interest, that blood that was known to be 
 capable of producing the disease was found to be absolutely harmless 
 after it had been heated to 131 F. for 10 minutes. At this time I 
 produced six additional yellow fever cases, all of whom recovered. 
 
 Such were the results obtained by the Army board, and they can 
 be summarized as follows: 
 
 1. Bacillus icteroides of Sanarelli was shown to be practically 
 identical with the bacillus of hog cholera, from which it differs only 
 in the source from which it is obtained. 
 
 2. Yellow fever is transmitted by a mosquito of the genus Stego- 
 myia, and all attempts to bring about the infection through contact 
 with bedding, clothing, and dejecta of yellow fever patients have 
 resulted in failure. Hence it follows that disinfection against yellow 
 fever is valueless. 
 
 3. Yellow fever can be produced experimentally, by the injection 
 of blood drawn in the first and second clays of the disease, but this has 
 no direct bearing upon the transmission or prevention of the disease 
 in its epidemic form. 
 
 4. The specific germ of yellow fever is sufficiently minute to pass 
 through the pores of a bacteria-proof filter, and it is destroyed by a 
 temperature of 131 F. 
 
 Confirmation of the mosquito inoculations has been furnished by 
 Dr. Guiteras, in Habana; Drs. Ribas and Lutz, as well as the French 
 commission, in Brazil, and by a commission of the United States 
 Public Health and Marine-Hospital Service, at Veracruz. It is espe- 
 cially gratifying that a French commission from the Pasteur Institute, 
 working recently in Brazil, has confirmed practically all the results of 
 the American Army commission. 
 
 The following, therefore, may be safely assumed: 
 
 1 . Disinfection in the prophylaxis against yellow fever is effective 
 only when it takes the form of fumigation and destroys mosquitoes. 
 
 2. Yellow-fever patients can be the source from which other cases 
 spring only when they have been bitten by the proper mosquitoes ; 
 consequently, in the yellow-fever zone all acute febrile cases not 
 diagnosed should be handled as though they were yellow fever, and 
 should be kept rigidly behind safe mosquito screens and netting. 
 So far as has been shown the yellow-fever patient is dangerous when 
 bitten by mosquitoes during the first three or four days of the fever 
 
214 YELLOW FEVER. 
 
 only, but since relapses may occur, every precaution should he 
 maintained as long as the temperature remains elevated. 
 
 3. The hospital intended fur the treatment of suspected 08866 of 
 yellow fever should be located upon ground that is high, well drained. 
 a\\ay from creeks, pools, or standing water of any kind, free from 
 mosquitos, and not surrounded by grass or shrubbery. All entrances 
 and exits to such hospitals should be provided \\ith doM'-mcshed 
 wire !>. and similai -hotild he fixed immov- 
 ably over every and other opening communicating \\ith the 
 
 nor. Standing water should not he pern.it ted in hanvls or 
 vessels of any kind, and broken crockery, tin cans, or other po^ihle 
 ners of rain water should he systematically searched for within 
 :ius of several hundred yards, and removed. 
 
 4. Jn general sanitation, all surface pools should he promptly 
 drainecl and iilled in with gravel, or covered \\ith petroleum. l'< 
 leuin should be applied systematically to standing \\ atcr in all ditches, 
 pools, rain-water gutters, etc.. that can not he tilled up or emptied. 
 The margins of ponds should be deepened, to enable the fish to reach 
 mosquito larvae. 
 
 5. Water should not be permitted to stand uncovered in hoi 
 and rain water in cisterns or barrels, when not used for drinking 
 purposes, should be treated with petroleum; if the water is u-ed for 
 drinking, all openings, vents, etc., should be closed \\ith win 
 
 or tightly fitting covers. Periodic examinations should then he 
 made for wigglers Oarva?) or mosquitoes, because the female mosquito 
 may pass through a very minute opening when seeking \\ater on 
 which to deposit her eggs. By means or these and other similar 
 measures, the number of mosquitoes may be greatly reduced, and the 
 chances for the conveyance of the infection, should it happen to he 
 present, will be thereby greatly diminished. 
 
 Stegomyia fasciata, the yellow-fever mosquito, is a house-dwelling 
 and house-breeding insect; particular attention should therefo: 
 paid to the smallest as well as the larger collections of standing water 
 within and about habitations. 
 
 6. After the removal of a patient, his room and the adjoining ones 
 should be at once tightly closed by pasting paper over all cracks and 
 openings, and then fumigated with insect powder, tobacco, or sulphur, 
 to destroy mosquitoes. When the room is opened after a few hours 
 these should be swept up and burned. 
 
 7. Experience at Habana has shown that patients suffering from 
 yellow fever upon their arrival at a port can be carried through a 
 thickly populated city to a properly screened hospital, and there 
 treated \\ithout the slightest danger to the community, so 1m. 
 they are rigidly protected against mosquitoes. Money spent for the 
 purpose of disinfection against yellow fever is wasted, for yellow 
 fever in epidemic form can only be contracted through the bites of 
 mosquitoes of a single genus. 
 
 8. The i>on contagiousness of yellow fever was clearly shown in 
 ain localities years ago before the use of disinfectants, in plae.-- 
 
 where the yellow-fever mosquito did not exist. The belief in the 
 supposed contagiousness of this disease arose from its trai : 
 through the atmosphere by the mosquito at a time when this insect 
 was not suspected or known to be concerned in the transmission of 
 any disease. 
 
YELLOW FEVER. 215 
 
 9. When a house is infected with yellow fever, it simply contains 
 infected mosquitoes; in the absence of this insect, no amount of 
 filth, heat, or moisture is capable of generating the disease. 
 
 10. Vessels from infected localities should be compelled, upon 
 entering port, to anchor at least a fourth of a mile from shore; they 
 should never be permitted to tie up to a wharf or dock in the city, 
 except in northern latitudes during the cold season of the year. In 
 this way, the chances for contaminated mosquitoes reaching the city 
 can be reduced to a minimum. 
 
 1 1 . As the yellow-fever mosquito does not bite, as a rule, between 
 the hours of 9 a. m. and 3 p. m., it is practically safe for nonimmunes 
 to visit infected localities between these hours for the transaction of 
 business. Before 9 a. m. and after 3 p. m. they will run a greater 
 or lesser risk of being infected. 
 
 12. It is now certain that before the lapse of many years, the dis- 
 ease, yellow fever, will have become extinct. The length of time 
 necessary for its complete eradication will depend upon the readiness 
 of our southern neighbors to accept the mosquito theory in toto, 
 and institute in their infected seaports vigorous and energetic meas- 
 ures based upon it. 
 
 13. Another epidemic of yellow fever should never be seen in the 
 United States. An example has been shown in Cuba, and the meas- 
 ures necessary to prevent the extension of the disease are so simple, 
 so plain and practicable for persons in authority, that the existence 
 of an epidemic of yellow fever in our country should alone be regarded 
 as prim a facie evidence of the culpability of some responsible person. 
 
 In conclusion, I can not refrain from asking you to pay no atten- 
 tion to the sensational letters, already referred to, as recently pub- 
 lished from a well-known American physician on the island of Cuba. 
 This gentleman was at one time regarded as an authority upon yellow 
 fever, of which he has seen a great deal, but he is now five years 
 behind the time. His insinuation that cases of yellow fever are still 
 frequent in Cuba, and that they are called typhoid fever, is a scan- 
 dalous misrepresentation of the actual truth, and an unjustifiable 
 reflection upon the intelligence and zeal of Cuban physicians, like 
 Drs. Finlay, Guiteras, Agramonte, Albertini, and others, who realize 
 fully the responsibility that rests upon them, who have suppressed 
 yellow fever on the island for three years, and who are fully compe- 
 tent to deal with the situation there, now and in the future. 
 
i: 4. 
 
 LESSONS TO BE LEARNED FROM THE PRESENT OUTBREAK OF 
 YELLOW FEVER IN LOUISIANA. 1 
 
 By JAMES CARROLL, M. D., Assistant Surgeon, United States Army, Wa>lnn on D.O, 
 
 Tho pi-. NDfl t he a suitable occasion to invite aitenti. n to 
 
 several points in < nneetion with the epidemic occurrence of \< llo\v 
 . in the VIM' ics at the present as well as at ot her't ime-. 
 
 In tho discussion of the symposium on yello\ .t the meet b 
 
 the American Public' Health Association in Washington in : I 
 
 called attention 2 to the necessity during the epidemic season for 
 requiring physicians, in cities whore yellow fever is prevailing or 
 likely to prevail, to report promptly to the authorities all cases of 
 fever of any kind coming to their notice. This is necessary in order 
 that there may be no delay in the institution of proper mea-m 
 protect the community against extension of the disease if it be yellow 
 fever, for this extension will almost surely take place in tin- more 
 southern latitudes if the patients are not protected from mosqn i 
 at the outset. If all cases of undetermined fever were promptly 
 reported and at once protected from mosquitoes 3 it would hardly 
 be possible for the disease to spread if it were yellow fever; on the 
 other hand, where the physician waits for the appearance of black 
 vomit, the golden opportunity passes by, for it has been shown that 
 in practically all cases the disease can not be communicated 
 the fourth day of the fever. For this reason the diagnosis should he 
 anticipated, and all febrile patients should be immediately protected 
 from mosquitoes until it is shown by actual demonstration that they 
 are not suffering from this disease. Epidemics do not follow e 
 introduction of yellow fever; mosquitoes becoming infected may 
 die before they bite a nonimmune, or the patients may happen : 
 treated in a locality free from Stegomyia. A group of ca 11< >w 
 
 fever occurring without black vomit usuaUy receives the designation 
 bilious remittent fever, a diagnosis that should be erased from our 
 text books. Bilious remittent fever, acute in type and of short dura- 
 tion, appearing in the United States, is yellow fever, and it >hould 
 be so regarded. Bilious remittent fever was formerly regarded as a 
 type of malarial remittent, but that was before the use of the micro- 
 scope was found to be necessary for a positive diagnosis of ma I. 
 infection. We know now that malarial fever is not a disease of cities, 
 but of outlying districts, while the bilious remittent lever, so culled, 
 has been recorded in the cities, in epidemic form, and in such intii 
 association with yellow fever that fey some the diseases were deci 
 identical, and by others the latter was said to be only a modification 
 
 Read at the thirty-first annual meeting of the American Public Health Association at Boston, Sept. 
 
 Report'of the Proceedings of the American Public Health Association. > 291. 
 
 Since this paper was read, I have been informed by Dr. E. Lloeaga. president <>r it,.- superior Board 
 of Health of Mexico, that the line of procedure indicated is now belngloUowed in his t-o 
 
 216 
 
YELLOW FEVER. 
 
 of the former. Most interesting and important in this connection is 
 the statement cited by La Roche, 1 in his chapter on bilious remittent 
 fever, that ' ' the morbid appearances revealed on dissection are the 
 same in remittent as in yellow fevers." This statement, however, 
 was not wholly accepted by him, for he calls attention to the bronzed 
 appearance of the Fiver in certain remittents, a condition that we 
 know results only from malarial pigmentation. Now that we can so 
 easily differentiate malarial remittent and typhoid from yellow fever, 
 the diagnosis is much less difficult, except where yellow fever occurs 
 as a complicating infection. 
 
 Our confreres in Havana have demonstrated to us that it is pos- 
 sible to prevent the epidemic occurrence of yellow fever, while occa- 
 sionally admitting cases of the disease into tlie heart of a city in which 
 the climatic and other conditions are known to be most favorable for 
 its extension in epidemic form, and in which there are more suscep- 
 tible persons now than ever before. The method suggested here is in 
 'many respects similar to, and is based on, the one adopted during the 
 American occupation of Havana. 
 
 Since then it has been sufficiently demonstrated, in 1903 and again 
 in -1905, that under the lax system heretofore and now in vogue, 
 yellow fever can easily secure a firm foothold in certain of the south- 
 ern states and escape recognition until it has passed almost com- 
 pletely beyond control. On both occasions cited, the outbreak was 
 suppressed or limited only by the intervention of the General Govern- 
 ment, which, through the energetic action of the United States 
 Public Health and Marine-Hospital Service, finally succeeded in 
 checking two epidemics that threatened, to become little less than 
 national calamities. Great credit is due to those officials for the 
 success that was attained in spite of the extreme delicacy of the 
 situation and the passive opposition encountered from many quarters. 
 
 Our experiences in Cuba have shown that for the exclusion and 
 suppression of yellow fever absolute hygienic control is necessary 
 not only of the people at large, but of the patients as well, and espe- 
 cially of the practicing physicians. The aim of modern medicine is 
 the prevention of disease rather than its cure, and the safety and 
 welfare of the thousands of persons exposed demand that the proper 
 measures be instituted and rigidly enforced. No valid argument can 
 be brought forward to show why the United States should not be kept 
 as free from outbreaks of yellow fever as the city of Havana, its former 
 endemic home, has been during the past four years. 
 
 To attain this result the following requirements seem to be essential : 
 
 1. Our physicians, or at least those who are in control, must dis- 
 abuse their minds of the impression . that black vomit necessarily 
 occurs in the majority of cases of yellow fever. 
 
 2. During the epidemic season, viz, from about May 1 to October 
 31, and in the epidemic zone, physicians should be required to report 
 to the health authorities, immediately, all cases of fever of any kind 
 that come under their observation, whether among their patients or 
 not, and failure to do so should be made punishable under the law. 
 
 3. The board of health should be authorized to appoint, with 
 proper compensation, a commission of three experts, all of whom 
 should be men of high reputation as diagnosticians. It should be the 
 
 1 Yellow Fever, La Roche, Philadelphia, 1855, vol. i, p. 590. 
 
218 0\V FEVER. 
 
 duty of ' imnission to visit without delay all cases of fever 
 
 reported to the health authorities, and the onus of diagnosis shouhl 
 
 on the commission and not on the attending physicians. They 
 Cthecominissit.n) should visit each patient daily until the dia.ir! 
 is established or the patient sent to hospital, and they should tor- 
 
 i promptly to the health department a written report at each 
 visit. The commission should determine whether or not the patient 
 shall be treated as a possible case of yellow id their decision 
 
 should he final and obligatory on all concerned. 
 
 4. All patients presenting the symptoms of yellow fever, ami all 
 cases not cli 1 but remaining under suspicion, should he 
 
 d f.r treatment to a hospital especially located 
 
 :ded with wire I -<piito nets, and the whole or a 
 
 portion of which has been set anart for that purpose. The yellow 
 r wards or hospital should D6 under the direct control of the 
 senior diagnosis commission, and the patients should be treated by 
 physicians appointed Only on their recommendation and acting under 
 their direction. 
 
 5. In exceptional cases, to be determined by the commission, 
 patients under observation awaiting diagnosis could be treated in 
 their homes beneath mosquito netting, and in rooms properly pro- 
 tected with wire screens, until the nature of the case had been finally 
 settled to the satisfaction of the commission. 
 
 The commission and not the attending physician should he held 
 responsible for the enforcement of all clinical measures necessary for 
 the protection of the community, and they should be empowered to 
 emplov such help as seemed in their judgment to be required. They 
 should also be assisted at times by subcommissions appointed on their 
 recommendation. 
 
 Under such a system, conscientiously carried out, the occurrence 
 of an epidemic of yellow fever in any city would become an impossi- 
 bility. Objection can not be made on tne ground of expense if the 
 members or the diagnosis commission are paid only for every \ i-it 
 to a patient; under such an arrangement the cost to the city would 
 be trifling when compared with the losses now sustained by indi- 
 viduals and the whole community through the failure of practicing 
 physicians to recognize and report mild cases of the disease And 
 nerein lies the crucial point. The diagnosis must be anticipated 
 and the proper precautionary measures oe taken before the disease 
 has fully declared itself. Diagnoses of malarial remittent, and above 
 all of bilious remittent fever, must not be accepted as conclusive 
 until the presence of malarial or other parasites has been demonstrated 
 to the satisfaction of the members of the diagnosis commission. 
 Attention was called two years ago l to the fact that over and over 
 again, since the time of Benjamin Rush, yellow fever has stalked 
 abroad in our cities, unrecognized, under the guise of bilious remit tent 
 fever. The time has come when a diagnosis of bilious remittent 
 fever should no longer be accepted, for there is no such disease | 
 We may have malarial fever complicated with jaundice, but this 
 should not change the diagnosis of malaria any more than an accom- 
 panying icterus would change a diagnosis pf typhoid fever. Simi- 
 arly a complication of malaria no longer justifies the diagnosis of 
 
 i Journal Association of Military Surgeons, 1903, No. 4, vol. xlll, pp. 103, 199, and 200. 
 
 i; 
 
YELLOW FEVER. 219 
 
 typho-malarial fever, and that term has properly been discarded. 
 In numerous instances it is stated in the records of the older epidemics 
 of yellow fever that the disease was preceded'by, or began as, a bilious 
 remittent fever, just as in more recent times physicians have believed 
 that typhoid fever began as malarial fever. The conclusion is 
 equally untenable in both cases, and the deduction is obvious that 
 cases of so-called bilious remittent fever must be regarded and treated 
 as cases of yellow fever, unless a satisfactory specific cause for the 
 condition can be demonstrated beyond a doubt. It is proper to 
 mention here that in every one of the 22 cases of yellow fever pur- 
 posely inoculated by the Army Board in Cuba, a diagnosis of bilious 
 remittent fever would have been justified if it had not been known 
 that they were produced from true cases of yellow fever, for, although 
 some of them were severe, black vomit was absent from all. 
 
 It may seem unnecessarily severe to require physicians, under a 
 penalty, to report all cases of fever coming under their observation, 
 but no other means will attain the desired result, and the enormous 
 interests at stake demand that the methods instituted be thorough 
 and that they be rigidly carried out. The appointment of a board of 
 diagnosis, as has been suggested, will relieve the attending physician 
 from the odium that accompanies a diagnosis of yellow fever in a 
 doubtful case, and the board, fully appreciating the responsibility 
 that rests on them, may be relied on to do their duty. During the dis- 
 cussion on yellow fever before the American Public Health Associa- 
 tion at its meeting in Washington two years ago, already referred to 
 in my remarks, which were badly misquoted, 1 I urged the necessity 
 for requiring physicians, under a penalty, to report all cases of fever, 
 in order that they might be examined by a board of experts (as was 
 done in Cuba) and treated as cases of, yellow fever until the diagnosis 
 was established. Only last month, in a conversation on this subject 
 with a physician from a large city in Texas, he laughingly remarked : 
 " We never report our cases of yellow fever until we have about a dozen 
 of them." 
 
 The present epidemic in and about New Orleans only serves to em- 
 phasize the necessity for such regulations as are here suggested, and this 
 necessity is further emphasized by the statement in the public press 
 of September 5 that " Inspector Brady attributed the continued spread 
 of the disease to the unwillingness or inability of physicians to diag- 
 nose mild cases of yellow fever, and that physicians of standing and 
 ability look for black vomit before making a diagnosis.' ' We have else- 
 where 2 cited the occurrence of the same difficulty at Key West in 1889, 
 and we again assert that these physicians may be thoroughly con- 
 scientious and able men, but they are baffled by the differences between 
 the aspects of the disease as they actually find it and as they have been 
 taught by the best authorities to expect to find it. It is the manifest 
 duty of local health authorities, therefore, to relieve the physician of 
 the burden of diagnosis and to leave that and the adoption of protec- 
 tive measures to the board of expert diagnosticians. 
 
 In this connection I beg to be permitted to call attention to the 
 present situation at Jackson Barracks, a station of two batteries of 
 Coast Artillery, in New Orleans. By the seventh day of the present 
 
 1 Reports of the Proceedings of American Public Health Association, vol. xxix, 1904, p. 291. 
 a Journal Association of Military Surgeons, 1903, vol. xiii, No. 4, p. 201. 
 
220 YELLOW FEVER. 
 
 month a number of cases of yellow fever had appeared in the neighbor- 
 hood and seven of them in a block that approached within LOO reel of 
 the officer's quarters. Still t he garrison has not been removed and up 
 to the present time no Mn-le case has occurred amoiu: them: e\en 
 should a case or two appear an epidemic is not feared. The re. 
 for this is simply that the medical oihcers know that it is absolutely 
 within their power to prevent any epidemic extension of the disease; 
 they are constantly on the alert, ana all cases of fever are handled in 
 the beginning as though they mii:ht he yellow fever. 
 
 Again, at Fort Melntosh. in Laredo, Tex., in 1903, there were only 
 5 CMOS of yellow fever in a eommand of 111 officers and men. while 
 in the town alongside them over 1 ,<<)() cases and mere than ion deaths 
 occurred. It was found that the 5 men who became infected had 
 violated orders bv visiting the town at ni^ht without wearing the 
 prescribed mosquito head-nets, leather gauntlets, and leiru'in. 
 
 If, in t IIA presence of cases of yellow fever among and around them, 
 garrisons of soldiers can be protected from the infection in anything 
 epidemic form, it necessarily follows that the same measures and 
 the same degree of vigilance will protect a community, provided t he 
 physicians do their full duty and they are properly assisted l>\ the 
 authorities. The subject is one invohinir tne lives and intere>: 
 thousands of innocent persons, and the secret of success lies in et 
 vigilance, with the determination to allow no case, however mild and 
 doubtful, to escape the fullest precautions. 
 
DR ARISTIDES AGRAMONTE 
 
PART IV, REPORTS FROM SANITARY OFFICERS IN HABANA, CUBA, 
 DEMONSTRATING THE PRACTICAL VALUE OF THE SCIENTIFIC 
 FINDINGS OF MAJ, REED AND HIS ASSOCIATES ON THE YELLOW- 
 FEVER COMMISSION, 
 
 CHAPTER I. 
 
 SANITATION AND YELLOW FEVER IN HABANA. 
 
 HEADQUARTERS, DEPARTMENT OF CUBA, 
 
 OFFICE OF CHIEF SURGEON, 
 
 Havana, February 8, 1901. 
 
 The ADJUTANT GENERAL OF THE DEPARTMENT. 
 SIR: 
 
 YELLOW FEVER, ESPECIALLY FROM THE VIEWPOINT OF THE SANI- 
 TARIAN. 
 
 Yellow fever has played such a conspicuous and important part in 
 the mortality of Habana that it deserves special consideration. This 
 infectious disease may claim Habana as one of its oldest and most 
 favored haunts. It was here as early as 1720, if, as I believe, we are 
 justified in so regarding the outbreak of that date described by the 
 historian Pezuela, apparently imported from Vera Cruz. It there- 
 after broke out in occasional epidemics like the historic, ones of 1749 
 and 1762, the latter being particularly fatal to the Anglo-American 
 army which had just captured the city, and causing the conquerors 
 to relinquish their prize in 1763. From that day to this yellow fever 
 has been endemic in Habana, hardly noticeable in some years, a mere 
 smouldering fire when nonimmunes were few, but quickly lighting 
 up into a blaze as soon as the fuel of immigration came within its 
 reach. The result has been a thoroughly infected city, a source of 
 danger not only to its own inhabitants and the rest or Cuba, but as 
 well to all countries having commercial relations with it. 
 
 During the decade 1890-99, the recorded number of deaths was 
 4,831, giving an annual average of 483, with a wide range from 1,282 
 in 1896 to 103 in 1899. In 1900 the number of deaths was 310. 
 Thus yellow fever is not nearly as fatal in Habana as typhoid fever in 
 the United States, and its importance would seem to have been very 
 much exaggerated j did we not realize that its mortality is not fur- 
 nished by the whole population, but only a small proportion thereof, 
 that is, the nonimmunes probably never averaging more than 1 
 in 10. 
 
 Until a few months ago the mode of propagation of yellow fever 
 was uncertain; we were fighting an unknown enemy in the dark, an 
 
 221 
 
222 YELLOW FEVEB. 
 
 enemy so wily and elusive that we never knew to what extent- our 
 clumsy and expensive methods of warfare were successful. Hut. 
 very recently, much liirht has been thrown upon the subject as the 
 result of one of the most brilliant medical discoveries of the age. The 
 announcement long ago made by Dr. Carlos Finlav, of llabana, that 
 mosouiti the agent of transmission in yellow fever ha- been 
 
 verified and scientifically demonstrated by Maj. Walter Keed. Sur- 
 geon, United States Army, and his colleagues, in the most conclusive 
 manner. It is true that the germ itself, in spite of the da in 
 Sanarelli and his partisans, has not yet been isolated, but this i> ,,f 
 comparatively little moment to the sanitarian, more concerned with 
 prevention than cure. For our purpose, the mosquito is the enemy , 
 and all our efforts must be directed against it. This war should be 
 waged with a twofold object: the destruction of the malaria-bearing 
 anopheles and that of the yellow-fever bearing culex; thus, at the 
 same time, eradicating the two diseases which have contributed so 
 much to make Habana a byword of reproach among civilized nation^. 
 Practically, then, the problem consists: First, in Ending the haunts 
 and breeding places of mosquitoes and the best means of ex t i n.u r n ish i ni: 
 them; second, in carefully protectingyellow-f ever patients and all imn- 
 immunes with mosquito bars, so that mosquitoes may not be inf. 
 by the former and carry the infection to the latter; third, in i-datini: 
 patients, and also, as much as is possible, nonimmunes, so that mos- 
 quitoes biting the former may not be able to reach the latter. The 
 knowledge that mosquitoes do not travel far, seldom more than a few 
 hundred feet if shelter exists, and that each house practically bn 
 its own, simplifies the question. The data being thus plainly stated, 
 there does not appear to be insurmountable obstacles in the way. and 
 we may confidently expect to see yellow fever stamped out in I la hana 
 in the course of three or four years after the construction of a good 
 sewerage system, provided the same unremitting efforts are con- 
 tinued under intelligent medical supervision and with the unrot ricted 
 help of the State. 
 
 The isolation and protection of patients is a most important 
 measure, but hard of successful accomplishment on account of the 
 difficulty of discovering and recognizing all cases. Many patients 
 among the poorer classes are not seen by physicians, and the expe- 
 rience of the last two or three years has led us to believe, that many 
 cases, especially among young children, are so mild that they i 
 unrecognized or are wrongly diagnosed. From these mild, ambu- 
 latory, and consequently unprotected cases the fever is mostly spread . 
 It is only when the profession becomes convinced that such cases 
 really exist, and that, as foci of infection, they are as dangerous as 
 severe cases, that perfect results will be obtained. 
 
 Our present knowledge concerning the agency of the mosquito in 
 yellow fever explains much that was obscure oefore and furnishes 
 useful indications to the Military physician. For instance, the part 
 played by dirt and filth in the breeding and propagation of the i 
 was always problematical; now we know that they have nothing to 
 do with it, except inasmuch as they may attract and feed mosquitoes. 
 It is certain that in Habana, in 1900, no visible correlation could be 
 seen between dirt and yellow fever; the district which first became 
 strongly infected lies east and south of the Paraue Central, and is 
 one of the cleanest and best constructed, while tne most insanitary 
 
YELLOW FEVER. 223 
 
 wards became infected late in the season and only to a slight extent; 
 the malodorous district reserved to houses of ill fame did hardly have 
 a case. Yellow fever has not followed the poor and unclean, or the 
 march of previous infections, but rather the movement of nonim- 
 munes; wherever these located, there the infection searched and found 
 them, regardless of the hygienic conditions of their premises, the most 
 aristocratic apartments on the second and third floors being as liable 
 to its invasion as any of the hovels crowded around a patio. 
 
 We also know that digging the ground, either for purposes of cul- 
 tivation or construction or, for instance, the laying of sewers, is a 
 perfectly harmless operation so far as yellow fever and malaria are 
 concerned, provided no water is allowed to stagnate in any of the 
 cuts and ditches. The value of this knowledge on the eve of under- 
 taking our great work of sewerage can not be overestimated. 
 
 The positive agency of the mosquito in propagating yellow fever 
 would naturally argue the noncontagiousness of the disease and the 
 inertness of fomites; but in order that the demonstration might be 
 complete, Maj. Reed and colleagues also conclusively proved by 
 direct experiment that infected linen, bedding, and effects of all 
 kinds are powerless to convey the disease. This discovery must bring 
 about a revolution in our methods of disinfection and quarantine in 
 yellow fever. Disinfection becomes completely useless, since there 
 are no infectious germs to destroy. In a house where a case of yellow 
 fever has been under treatment the problem is how to reach the 
 mosquitoes which have become infected by biting the patient and 
 are still lurking in the vicinity. It is probable that a certain propor- 
 tion of mosquitoes, after feeding, fly out in search of water wherein 
 to lay their eggs, in the immediate neighborhood, but enough remain 
 in the patient's and contiguous rooms to require action. The best 
 way to destroy them, so far as now known, is by fumigation. Sul- 
 phur fumes are most efficacious, but otherwise so objectionable that 
 preference should be given to formaldehyde, which, as we know, is 
 much safer and more convenient. It kills mosquitoes in from 10 to 
 15 minutes, so that rooms treated with it need not be closed more 
 than three or four hours. The good effects of such fumigation seem 
 to have been proved in preventing the recurrence of a second case in 
 694 out of 885 infected houses in Habana, and by the absence of a 
 single case in Santiago de Cuba in 1900, after the epidemic of 1899. 
 
 The duties of quarantine officers have also become singularly sim- 
 plified. Since we may assume in practice that the infectious germs do 
 not exist outside of man and the mosquito, the disinfection of trunks 
 and baggage on account of yellow fever is no longer justifiable; all 
 that is required will be the examination of nonimmunes within the 
 five days immediately following their last exposure to infection, the 
 danger of transmission being from their own persons and in no wise 
 from their clothing or baggage. Ships, like houses, are liable to har- 
 bor infected mosquitoes and will continue to require fumigation. 
 
 From what precedes it must be evident that the two chief factors 
 in the propagation of yellow fever are mosquitoes and nonimmunes. 
 Nonimmunes are almost entirely furnished by immigration. Were it 
 possible to completely stop it, especially from Spain and the Canary 
 Islands, for two or three years, it is almost certain that during that 
 short period all germ-bearing mosquitoes could be destroyed, and 
 the city thereafter kept as free from infection as Kingston in Jamaica 
 
224 VER. 
 
 and San Juan in Porto Rico. Immigration, however, is too valuable 
 to the interests of the island to be stopped, or even cheeked, for the 
 sake of stamping out yellow fever, a disease without terror and of 
 little consequence to Cubans. It is only possible, then, to take such 
 measures as will protect as many aonimmunes as possible without 
 fering in any way with business interests. The plan lately 
 adopted i> practical and eilicient : All noninimune immigrants who 
 do not come in answer to a call from 1 lavana are taken to a detention 
 station on the healthiest site around the bay, where they await in 
 comfort and safety offers of employment. All employers of lab.. 
 as many as it is possible to reach, have been notified of the e 
 of this station and invited to engage there all the hand- they need. 
 Earnest efforts are made to send as many as possible of these immi- 
 grants to the rural districts where most wanted. In this way all are 
 benefited: the immigrant who procures work without hardship or 
 danger, the city of Havana, which is rid of dangerous nonimmune 
 airdomerations, and employers who are enabled to get as many hands 
 a< they may require with the least trouble and expense. 
 
 The relation which Spanish immigration has borne to yellow i 
 is important and interesting. It has been most active in pcrio 
 peace and prosperity, becoming small or stopping altogether in 
 of political disturbance and insurrection, and statistics show that the 
 spread of yellow fever among civilians is directly proportional to the 
 number 01 immigrants. 
 
 Soldiers, on the contrary, were few in years of peace and contrib- 
 uted little to the yellow fever mortality, but in troublous times they 
 were greatly and rapidly increased, beginning to arrive as the civil 
 immigration began to stop, so that their mortality curve rose as that 
 of the civil population fell. Thus, when the last insurrection b 
 put, in, 1895, immigration stopped; on the contrary, troops \x> 
 into Havana, and the result was a very high military mortality in 
 1896, 1897, and 1898. When the American troops took possession of 
 Havana on January 1, 1899, the whole population was practically 
 immune, and, the Spanish troops having departed, cases of yellow 
 fever ceased. The American troops formed the only susceptible or 
 nonimmune element and disciplinary measures were successful, with 
 one slight exception, in preventing their contagion. It the:. 
 happened, naturally enough, that only few scattered cases were 
 observed during the spring and summer of 1899. As soon as peace 
 was assured the current of immigration was resumed, and in greater 
 volume than ever. The result was immediately seen in the number of 
 cases, which steadily increased from August to December, the number 
 for December being larger than for the same month in any previous 
 year; this is more striking because the death rate of yellow fever 
 generally rises to its maximum in August and September and shows 
 a marked decline from October to December. 
 
 During the years 1899 and 1900, 40,384 immigrants arrived at 
 Habana, namely 16,260 in 1899 and 24,124 in 1900, a prcai majority 
 of them nonimmunes and at least 50 per cent remaining in the city 
 of Habana. They still continue to come at about the same r 
 With these figures of the largest i 1 1 1 migration on record in the same 
 space of time, what happened was to Be expected and unavoidable, 
 namely, an usually large number of cases of yellow fever in the 
 summer and fall of 1900 and corresponding high^mortality, although 
 
YELLOW FEVER. 225 
 
 the deaths (310) did not reach the annual average of the past decade. 
 The effect of cold weather on the infection was, as usual, well marked 
 from 74 in October the number of deaths decreased to 57 in Novem- 
 ber, 20 in December, and only 7 in January, 1901. 
 
 The subject of immunity against yellow fever is very interesting 
 and deserves a few remarks. Immunity is not enjoyed by all 
 Cubans, as popularly believed, but only by those residing in cities, 
 not by those who have lived from infancy in the interior rural dis- 
 tricts. In other words, immunity is only enjoyed by the residents 
 of centers where yellow fever is endemic; it is not enough to have 
 lived in a tropical climate; one must have lived in an infected locality. 
 The inference therefore is strong that immunity is acquired only by 
 an attack of the disease; there is no other infectious disease against 
 which immunity is obtained in any other way, and there is no reason 
 to believe that yellow fever is an exception to the rule. Under the 
 former belief that it was acquired by the absorption of germs through 
 the respiratory passages, it was possible to conceive the possibility 
 of a very slow but constant infinitesimal absorption which might in 
 time produce immunity without any apparent lever, but such a con- 
 ception is no longer tenable if the germs are introduced directly into 
 the blood by the mosquito. Those physicians who assume a priori 
 that Cubans, whether they live in the city or country, can not have 
 yellow fever, decline to recognize it when they find it in natives ; they 
 call it "fiebre de borras" and consider it a special form of malaria, 
 which, strangely enough, only occurs in this island. 
 
 Since the great majority of Cubans are immune and immunity is 
 only acquired by an attack of the disease, we are compelled to the 
 conclusion that nearly all natives of Cuba must have yellow fever 
 in their youth probably in the first few years of their lives. At 
 that age the disease appears to be mild and comparatively harmless, 
 and we may fairly assume that the 5,000 children annually born in 
 Habana have it in such form that it is generally unrecognized by 
 physicians who diagnose it under the comprehensive headings of 
 malaria, calentura or meningitis. In this connection it is interesting 
 to observe that in epidemic years the proportion of deaths among 
 children, not diagnosed yellow fever, is noticeably greater. 
 
 Here an interesting question suggests itself. If Cubans have yellow 
 fever in infancy in such a mild form as not to endanger life and remain 
 immune thereafter, why should they endeavor to eradicate the dis- 
 ease in the island, so that their descendants will lose immunity and 
 become liable to any epidemic that may break out hereafter? The 
 answer is that foreign visitors and immigrants have natural rights 
 that Cubans are bound to respect; that epidemics can be guarded 
 against and avoided ; and lastly, that although Cuban infants have 
 the disease in an apparently mild form, it will probably be found, 
 when the matter is investigated and the obscure diagnoses of many 
 of the reported cases of death carefully analyzed, that a larger pro- 
 portion of deaths among children than is generally believed is due 
 to yellow fever or complications therefrom. 
 
 A few words in closing upon the result of treatment of yellow-fever 
 cases at Las Animas hospital, an establishment intended for the 
 reception and treatment of all contagious diseases, but chiefly yellow 
 fever. During the year 1900 it was under the direction of Maj. 
 W. C. Gorgas, chief sanitary officer, who devoted to it much of his 
 79965 S. Doc. 822, 61-3 15 
 
226 YKI.l.OW l l VI i;. 
 
 valuable time. The hospital is pleasantly situated in the outskirts 
 of the city and as completely equipped with material and personnel 
 &8 any hospital of its kind in the I'niled States. Ameriean trained 
 nurses being in attendance. An ainlndance. carrying physician 
 and nurse, is :d\\ays in readiness to go when summoned, and the 
 v is taken to save patients all unnecessary fatigue or 
 exertion in transit. 
 
 The patients sent to this ho-piial may he divided in l \\ o rla- 
 Kirst. Americans (including few nther foreigners), the majority of 
 them brought there at their o\\ n request early in the disease, hut 
 includiiiLT al>o not a few homeless vagabonds and drunkards ; second, 
 Spaniards, mostly of the lowest classes, too poor and thriftless to 
 belong to any of the <|iiintas <le salud. 
 
 It can easily be seen therefore that Las Animas receives m'>t of 
 the worst cases, generally after the disease has lasted several days. 
 not infrequently the patients being unconscious and occasionally 
 moribund, as shown by the fact that out of ."is deaths. Is occurred 
 within three <lays after admission. During the year. L'7'J < 
 of yellow fever were admitted: 1(>7 Americans. 71 Spaniards, and 
 ::i of other nationalities: J M recovered and ."is died. gi\ inir a 
 general death rate of 'JL.'W. Taking the three leading and bc-l 
 conducted private hospitals in llabana for comparison, namely. 
 the Dependientes, (\>\ adonga. and Beneiica, we lind that during the 
 year their yellow fevi r death rates were 24.35, -7..M. and 24.35 
 respectively, each higher than that of Las Animas, although their 
 patients, being members of the centros or clubs to which the hospi- 
 tals belong, are generally admitted early in the course of the di 
 and therefore in much more favorable condition- for succe ful 
 treatment. 
 
 At Las Animas the death rate of Spaniards was 36.48 and that of 
 Americans 12.57, a most remarkable difference when we bear in 
 mind that all patients there receive the same identical treatment 
 in the same wards. This difference is partly due to the fact that 
 Americans are in better physical condition, with greater power of 
 resistance, but chiefly to the circumstance that they are admitted 
 early and have the full benefit of the treatment. In this respect 
 the status of Americans at Las Animas may be fairly compared to 
 that of the Spaniards received at the above-mentioned hospitals. 
 and yet their mortality is only one-half that of the latter. Such 
 results furnish food for reflection. At Las Animas patients are 
 treated almost entirely on the expectant plan; medicines are avoided 
 until there is a clear indication for their use: absolute re>i. very 
 careful dieting, and the constant attention, day and night, of trained 
 nurses have been the main features of treatment. The key to 
 success in the treatment of yellow fever, I believe, is good nuixiii" 
 at the hands of specially trained women. Such nur>ing is e\pen>i\e. 
 and in Cuba has been practicable, so .far, only in few other ho-pitaU. 
 but any method of treatment which saves lives H always found to be 
 the cheapest. 
 
 V. 1 1 \ v vi:i. 
 Major and Surgeon, Unltnl Shifr* Arm;/. < '/< iff Surgeon. 
 
CHAPTER 2. 
 REPORT OP THE HABANA YELLOW FEVER COMMISSION. 
 
 HABANA, January 3, 1902. 
 
 SIR: In compliance with your request that I should make a report 
 of my department, as chairman of the Yellow Fever Commission, for 
 the six months ending December 31, I have the honor to inclose the 
 said report. 
 
 Very respectfully, CHARLES FINLAY, 
 
 Chairman of the Yellow Fever Commission. 
 Maj.W.C.GoRGAs, 
 
 Surgeon, United States Army, 
 
 Chief Sanitary Officer ofHabana. 
 
 HALF-YEARLY REPORT OF THE HABANA YELLOW FEVER COMMISSION, JULY TO 
 
 DECEMBER, 1901. 
 
 During the ^resent term (July 1 to Dec. 31, 1901) the Yellow 
 Fever Commission of Habana has examined and investigated 118 
 cases, reported as follows: 94 yellow fever suspects (37 of which 
 were confirmed as "natural yellow fever" and 10 as "experimental 
 yellow fever"); 7 suspected glanders (the diagnosis was confirmed 
 in 4) ; 4 leprosy (confirmed in 3) ; 6 suspected smallpox (none of 
 which were confirmed) ; 1 typhus fever (not confirmed) ; 1 relapsing 
 fever (not confirmed); 5 reported as "infectious fever" (in 2 that 
 diagnosis was maintained, inasmuch as these cases, while presenting 
 clinical characters suggestive of an infection, could not be identified 
 as malaria, typhoid, influenza, and Malta fever, and were therefore con- 
 sidered as belonging to the group of ' ' Tropical unclassed fevers) . 
 
 The 37 cases diagnosed as "natural yellow fever" have been dis- 
 tributed in Table I, so as to differentiate those whose infection had 
 originated in this city from others who were brought to Habana, 
 already sick or infected, from other parts of this island, and also 
 from those who came from foreign ports. 
 
 TABLE I. 1901. 
 
 
 July. 
 
 August. 
 
 September. 
 
 October. 
 
 November. 
 
 December. 
 
 Totals. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Cases. 
 
 Died. 
 
 Habana 
 
 7 
 
 6 
 
 
 3 
 
 1 
 
 
 
 7 
 
 3 
 
 1 
 
 1 
 
 
 
 
 9 
 
 
 
 
 2 
 
 
 
 
 
 
 
 1 
 1 
 
 
 
 
 
 
 
 
 
 2 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 23 
 
 10 
 
 4 
 
 6 
 
 1 
 1 
 
 Other towns 
 (Cuba) 
 Foreign ports.. 
 
 13 
 
 4 
 
 11 
 
 1 
 
 9 
 
 2 
 
 2 
 
 
 
 2 
 
 1 
 
 
 
 
 
 37 
 
 8 
 
 227 
 
228 
 
 FELLOW FEVEB. 
 TABLE U.Expfrimentalcasa. 
 
 Pled 
 
 October. November 
 
 Cans. 
 
 ber. I Nove 
 Died. Cans. 
 
 Pled 
 
 Totals. 
 
 Ill 
 
 The wonderfully small number of yellow-fever cases and deaths in 
 Hahana duriiu: the epidemic ,.f the present yearia an unprec- 
 
 edented event, and since it can not be accounted for by any climati-- 
 tinns nor by a lack of nnnimmunes or of opportunities fur a 
 reproduction of the yellow-fever jjcrni through the introduction of 
 > from outside, we are bound to admit that it must be attributed 
 to the killing of contaminated mosquitoes when > \\ere sup- 
 
 posed to exist, and to the protection of noniiumunes in mity 
 
 of infected houses against the bites of those insects, as the sanr 
 department has been doing since Februar} r . 
 
 MANNER IN WHICH THE INVESTIGATION HAS BEEN CONDUCT K I >. 
 
 The conclusive demonstration of the mosqui to theory by l>r. Meed, 
 a year airo. and by Dr. Guite'ras this summer has made it all the 
 more necessary that the investigation of \cllo\\-fe\ ci <1 be 
 
 carried out with jrreat care, so as to secure a reliable dia- : id to 
 
 discover, if possible, the source whence the infection hasLecn derived. 
 
 The method practiced by the commission has been as folio v 
 data contained in the original report are carefully gone over at the 
 bedside of the patient and additional particulars inquired into in order 
 to discover, if possible, the probable source of his infection. A clinical 
 history of the case having been obtained from the physician in ch. 
 it is minutely scrutinized, and the patient is then carefully examined 
 by each of the members present. Particular attention is given to the 
 examination of the urine for albumen, and it is believed that, while 
 sources of error are avoided, so small a quantity as 10 centigrams of 
 pure albumen per liter would not escape detection, ; >.:ni/.able 
 
 trace, by the methods employed. The different organs are ex pi 
 to detect or exclude any lesion to which some of the symptoms might 
 be attributed, and every circumstance in antecedents ol the patient 
 is duly taken into account. 
 
 As a rule, the secretary of the commission, before the meeting of t he- 
 board, has collected blood, sputa, pus, or other available material. 
 according to the nature of the disease reported, and the said material 
 has been examined for malarial parasite or bacteria, tried with the 
 \Yidal test, etc. In the case of private patients, supplementary infor- 
 mation has been obtained by the secretary from the atiei,. 
 physician, and, if necessary, the latter is requested to be p 
 meeting of the board. Whenever any doubt remains in the minds 
 of the members the decision is deferred and the patient rcc\:- mined 
 as often as may be necessary. In fatal cases, provided the family or 
 friends of the patient do not obj. autopsy is made, notes of the 
 
 findings recorded, and hystolugieal specimens preserved or cultures 
 prepared for subsequent examination. The physician in < 
 always expected to notify the commission or to report the case again 
 
YELLOW FEVER. 229 
 
 if the subsequent course of the attack should throw some doubt upon 
 the decision of the board, in which event a reversal of the first diag- 
 nosis would be voted if the majority of the members decided that 
 there was occasion to do so. 
 
 USEFULNESS OF EXPERIMENTAL CASES FOR DIAGNOSIS. 
 
 In the diagnosis of mild cases of yellow fever it has been of great 
 advantage to the commission to have the support of Dr. Reed's 
 observation in one of his experimental cases, showing that an un- 
 doubted attack of the disease may run its full course without present- 
 ing any trace of albumen in the urine. Similar cases had been 
 observed in private practice by members of the commission, and some 
 of them have come before the board. The same may be said with 
 reference to the importance of the typical fever curve as an element 
 of diagnosis in nonalbuminuric cases. 
 
 SOME KNOWLEDGE OF THE LIFE CYCLE AND HABITS OF THE STEGOMYIA 
 NECESSARY IN ORDER TO FOLLOW TRACK OF AN EPIDEMIC. 
 
 The importance of ascertaining the source of the infection in every 
 confirmee! case of yellow fever is self-evident, since the sanitary 
 department is thereby enabled to take prompt measures calculated 
 to control the propagation of the disease. But that investigation, 
 according to the now accepted etiology, can not be successfully 
 accomplished without a knowledge of certain details concerning the 
 life of the yellow-fever mosquito which are not easily found in the 
 current literature on that subject, and it may not be considered out 
 of place to recapitulate them in this report. 
 
 The species of gnat which transmits yellow fever (Stegomyia 
 txniata, Theob.-Culex mosquito, R. D.) is diurnal and crepuscular, 
 for it may be met with at any hour between daybreak and nightfall, 
 and takes its rest during the night. The males never bite nor suck 
 blood; the females only do so after they have mated, and never lay 
 their ova before having sucked blood. After a complete feed of 
 blood the insect will not bite again until all the contents of its stomach 
 have been digested or discharged ; this process requires from 48 to 60 
 hours in summer, but may be delayed 2 or 3 days more in cool 
 weather. The wings of the Stegomyia are so small that after a full 
 meal it must be unable to fly to any height or even to any consider- 
 able distance on a level. It shuns the sunshine, avoids flying across 
 open waters, and keeps away from the wind. Its eggs are laid in a 
 peculiar manner, some entirely out of the water, so that they are apt 
 to remain unhatched during several weeks or months, and yet may 
 develop a brood after that lapse of time when they happen to be cov- 
 ered with water of a suitable temperature. It is probably by this 
 means that the species is propagated during the cooler months of the 
 Cuban climate. The Stegomyia breeds in any collection of water 
 (a very small quantity is needed) in the yards, gardens, basements of 
 nouses, often in the lye water used by washerwomen in this country; 
 but also inside of rooms when water has been allowed to stand sev- 
 eral days in basins, jugs, or open bottles. A new brood may develop 
 in 9 or 10 days if the larvae are abundantly provided with food (bread 
 crumbs seem to agree very well with them), otherwise several weeks 
 may elapse .before the winged insect emerges from its pupa case. 
 
230 
 
 When the temperature falls to 20 C. the insert is disim -lined to 
 fly, and below 15 or 10 (\ it is benumbed and unable cither to fly 
 or to bite. It is killed by temperatures below five/iiiir point or 
 fcbove 45 C.; probably :in U)32 C, i- it- optimum temperature. 
 
 The Steiromyia ia very domestic in its habits and will not be likely 
 to leave the premi-es oii which it has taken up its quarter- BO long as 
 it finds in it the necessary conditions for the completion of its life 
 cycle (opportunities for satisfy i m: it- craving for human blood, water 
 in which it may lay its ova, and an agreeable atmosphere Miitcd t<> it- 
 tastes ami of the reouired tempera! nv) In the ah-ence of any of 
 [risitefl it will migrate into the nearc-t place where they may 
 be sati-tied. 
 
 The Stegomyia becomes con tamin at e(l and acquires the faculty of 
 t ran-mit tinu r the disease only after having bitten a yell. 
 lat lent within the first 5 or 6 days of his attack. During the li 
 or 3 days of its contamination its bite may sometime-, i an 
 
 attenuated form of the disea-e. but after that period the insect loses 
 for a while the faculty of inoculating the disease in any form, ami it 
 is only when 12 or more days have passed since its contamination 
 that it acquires the power of producing a well-marked attack of yel- 
 low fever, the virulence of its oite being then considerably greater in 
 summer than in winter. The contaminated Stegomyia retains t ' 
 after, during its lifetime (which may last 70 aays), the facult 
 reproducing the disease every tune that it chances to bite a non- 
 immune. 
 
 The manner in which a nonimmune may become infected is appar- 
 ently under the following circumstances: 
 
 (1) By visiting a place where contaminated mosquitoes exist, at a 
 time when those insects happen to be in a condition to bite and pic- 
 pared to inoculate the disease. 
 
 (2) By the fact that a case of yellow fever has occurred in the 
 neighborhood and mosquitoes contaminated from that patient have, 
 for some reason, been induced to migrate into the non immune 's 
 dwelling. 
 
 (3) By the conveyance of contaminated mosquitoes in parcels, 
 boxes, etc., or, possibly caught under a hat while biting the nead of 
 a visitor on his way to the nonimmune's house. 
 
 (4) During the hot summer days the Stegomyia is apt to fly out 
 into the street, under porches, etc., suggesting the possibility of their 
 biting a yellow fever patient on his way to the hospital if the carriage 
 or the unprotected ambulance happens to be detained. In Mich a 
 case, the insect, thus contaminated, would afterwards take refuge 
 in one of the houses on the road to the hospital, and the imnimmnnes 
 in that house might, in due time, be inoculated by the infected 
 mosquito. 
 
 A PRACTICAL ILLUSTRATION OF THE MOSQUITO THEOIM 
 
 As an illustration of the ways in which the yellow fever may be 
 acquired, according to the preceding statements, and <>f the dillicul- 
 ties with which the sanitary department has had to contend this 
 year in preventing the disease from spreading over the whole city. 
 the following instance may be given as one in which the yellow fever 
 commission was deeply interested. 
 
YELLOW FEVER. 231 
 
 In one of our best hospitals in this city (Quinta de Dependientes) 
 the upper story of a new building is reserved for yellow fever patients 
 and suspects. That floor being divided into a right wing for con- 
 firmed cases and the left wing for cases under observation, the landing 
 of the stairs occupies the space between the two large screened doors, 
 facing each other and opening into each of the two departments! 
 Though well provided with wire netting, two defects were subse- 
 quently noticed in the disposition of these wards: the height of the 
 ceilings, which prevents mosquitoes from- being seen when they 
 occupy the upper part of the rooms, and the absence of any syphon 
 or trap in the pipe leading off the water from a basin under the 
 hydrant. Under these conditions, mosquito larvae might be bred 
 outside the building where the defective pipe opens and the winged 
 insect might find its way into the yellow fever ward, remaining there 
 unseen after having bitten some of the patients. In fact, larvse 
 were observed by us, on one occasion, in the water jug used in that 
 ward. 
 
 On the 14th of August of this year, two nonimmunes were admitted 
 into the observation ward with a fever which appeared suspicious 
 but only turned out to have been a mild attack of influenza. Both 
 were discharged on the 18th. One of them lived at Florida Street, 
 No. 2*4, the other in a bakery in Aguila Street, No. 185, opposite 
 the Tacon market. The man from Florida Street was attacked, on 
 the 20th (two days after leaving the hospital) with fever and devel- 
 oped a mild yellow fever. His "house was duly fumigated and all 
 the contaminated mosquitoes must have been killed, for no other 
 case occurred in that neighborhood. The other man (No. 1), who 
 lived at the bakery, was also attacked with yellow fever, but not 
 until the 24th (six days after leaving the hospital), and two other 
 men (Nos. 2 and 3), who worked in the same bakery and slept in 
 rooms near his own, were also attacked, on the same day and the 
 next respectively (Aug. 24 and 25). We must therefore infer that 
 No. 1 had brought with him from the hospital some of the contami- 
 nated mosquitoes which had inoculated him, and the incubation was 
 shorter in the two other men than in his own case. The bakery was, 
 of course, fumigated and most of the contaminated mosquitoes 
 probably killed; but the disposition of the house and of its neighbor- 
 hood was particularly unfavorable, and some of the numerous insects 
 which had had & chance of biting one or other of the three simul- 
 taneous cases must have escaped and flown across the narrow street 
 into the porch of Tacon market, where fruit and flower venders lay 
 out their goods on the floor under the porch and sit or stand the 
 greater part of the morning waiting for purchasers. Two of those 
 flower venders (Nos. 4 and 5) were attacked with yellow fever on the 
 7th and llth of September, respectively; the last of these developing 
 into a fatal case, the first of the series. These two men lived in the 
 Cerro, where they had their garden near Tulipan Park. 
 
 Their dwelling was fumigated effectively, for no other case of yellow 
 fever occurred m the neighborhood. The owner of the bakery on 
 Aguila Street lived in a house at the back of it, on Amistad Street, 
 No. 136, and (No. 1), when questioned by the members of the com- 
 mission at the hospital, had told them that after his attack of influ- 
 enza he had first gone to the owner's house. That house was there- 
 fore probably infected and duly fumigated ; but from here also some 
 
232 YELLOW 
 
 of the contaminated insects must have escaped and taken refuse in 
 a oaf 6 close by, Amistad Street, No. 130, where the hartendci 
 was attacked with yellow fever on the 12th of September. This 
 house was also fumigated, but the >ame contaminated insects which 
 had bitten this case or others from the same source must have ciX) 
 Dragones Street and entered another hou>e in the next block. AHUM ad 
 l .5, where a man servant i No. 7) was attacked witli fatal yellow 
 fever on the 14th of September. The next two cases occurred in t wo 
 newly arrived immigrants (No. 8 and No. 9) who lived together in a 
 room at Kicla. No. :V2, a food distance from the infected ouarter: but 
 they informed us that they were in the habit of going almost every 
 evening to a house in the block next to that of (No. 77 Amist ad 
 96, but on the other side of the street, to chat with an immune IV 
 of theirs. These two men were attacked on the 21st and 22d of 
 September. The killing of mosquitoes at their dwelling pr< 
 efficacious, for no other cases occurred near Kicla 32: hut a lew of 
 the contaminated insects still remained in the block of (No. 7), for in 
 a large tobacco factory occupying the south front of that block two 
 of the workmen (No. 10 and No. 11) were attacked on the Jxth of 
 September. This time, however, the fumigation and killing of the 
 mosquitoes within and around the tobacco factory must have killed 
 the last of the infected insects, for no other case of yellow fever has 
 been reported since in Habana. 
 
 DESIDERATUM. 
 
 The danger of new invasions which might insidiously acquire such 
 proportions that they should prove difficult of control, comes prin- 
 cipally from the want of a sure landmark by which to recognize even 
 the mildest forms of the disease, a want which, it is feared, must 
 subsist so long as the germ of the disease has not been definitely 
 identified. With the certainty that the said germ is contained in 
 the blood of the patient and also in the head of the contaminated 
 stegomyia, it was thought that Drs. Reed and Carroll could not 
 fail to discover that germ, knowing that they had apparently the 
 best of materials to work upon and the assistance or experts well 
 trained in the investigation of animal and vegetable germs. Their 
 failure to do so has therefore caused general disappointment. The 
 Yellow Fever Commission, howerer, considers it one of its duties not 
 to let the matter drop ; and to avail itself of Dr. Guiteras s permission 
 and valuable cooperation for pursuing the search for the yellow-fever 
 germ at the laboratory of his experimental station whenever a fa\ Ar- 
 able opportunity for doing so presents itself. 
 
 CHARLES FINL.U . 
 Chairman of the Yellow Fever Commission. 
 
 HABANA, January 3, 1902. 
 
 Many years before the Yellow Fever Commission was organ i/ed, 
 Dr. Carlos J. Finlay, of Habana, had formed the opinion that yellow 
 fever was conveyea by the bites of mosquitoes and had fbcea upon 
 the Stegomyia calopus as the culpable airent. On June 30, 1881, 
 he began a series of experiments to prove the transmission of the 
 
YELLOW FEVER. 233 
 
 disease by this insect, believing that he could in this way produce a 
 mild type of fever which would convey immunity. He bred the 
 mosqvitoes in captivity and developed a technique for transporting 
 them and placing them upon the patients, and between the date 
 above mentioned and the arrival of the Yellow Fever Commission in 
 Cuba he had made 103 experiments of which he regarded a consid- 
 erable number as successful. 
 
 In the light of our present exact knowledge of the length of incu- 
 bation of yellow fever in man and the considerable period of incuba- 
 tion in the mosquito between the time of biting and when she be- 
 comes able to transmit the infection, and also the very brief period 
 (three days) at the begining of the disease during which alone the 
 patient is able to infect the mosquito, it must be recognized that 
 probably none of Dr. Finlay's experiments were successful, but none 
 the less must credit be given for what Col. Gorgas has termed the 
 11 scientific clairvoyance" with which he had conceived his theory 
 and the enthusiasm 'with which he maintained it. 
 
 When Maj. Reed went into Habana to consult him, before begin- 
 ning the work of the board, he gave him eggs of Stegomyia calopus 
 which he specifically stated were those of the mosquito which con- 
 veyed the disease, and the first experiments of the board were made 
 with mosquitoes grown from these eggs. As Dr. Finlay was the 
 originator of this theory, and was of great assistance to the com- 
 mission, the above report of his, which is of scientific as well as his- 
 torical value, is published in this place, although it is recognized that 
 some of the views expressed by him are at variance with the findings 
 of the commission. 
 
( '1! MM FU 3. 
 
 REPORT OF MAJ. W. C. GORGAS, MEDICAL CORPS, UNITED 
 
 STATES ARMY. 
 
 1 1 KADQUARTERS DEPARTMENT OF CUBA. 
 
 Miiicr Of (11111 S\\ITAKY OFIICKK OF 11 \BA\A, 
 
 .Inly 12, 1902. 
 
 (.! \n:\i : I herewith forward the report of the sanitary depart- 
 ment. hrinLrinu: the account of the work up to May 20 of the pr< 
 year. 
 
 This hcini: the final report of the sanitary department of the city 
 of Hahana under the military government, it miirht he useful to 
 review, in a general way, the work of the department since its incep- 
 tion in 1899. 
 
 The great object of sanitation for Cuba, and particularly for 
 Habana, as far as the United States was concerned, was the erad- 
 ication of yellow fever. For over 200 years this disease had, at 
 short intervals, devastated the Atlantic and Gulf coasts of the 
 United States, causing great loss of life, and still greater iinancial 
 loss, due to the entire cessation of commerce which occurred during 
 the epidemic. It is estimated that the money loss caused directly 
 by the epidemic of 1878, which affected particularly the lower 
 Mi-sissippi Valley, amounted to $100,000,000, and in years when 
 there was no epidemic quarantines had to be kept up against the 
 infected regions around the Gulf of Mexico, which stopped almost 
 all travel and greatly interfered with commerce. The United 
 States had come to look upon Habana as the particular point from 
 which infection was spread. Yellow fever has been continuously 
 present in this city since 1762. Every month in every year during 
 that time there have been some cases. In all other localiti. 
 X< rth America where yellow fever occurred, it occurred epidemically ; 
 that is, the locality was free from the disease for a longer or shorter 
 time. In places above the frost line winter always puts an end to 
 the disease, and in localities in the Tropics it always terminates after 
 a greater or lesser period of years from the exhaustion of the nonim- 
 mune material. It was therefore hoped by the military authorities 
 that if yellow fever could be controlled in Habana the United S: 
 would be free from danger of epidemic invasion. 
 
 One of the most prominent objects, then, that the military govern- 
 ment had before it during its stay in Cuba was the control of yellow 
 fever, and for this purp< -e we paid great attention to the improve- 
 ment of the hygienic conditions all over the island. But Ha 1 
 being the only endemic focus in the island, and. for that matter, 
 anywhere else in North America . the energies of the military govern- 
 ment were concentrated at this point. 
 
 None who knew anything of yellow fever had any dear idea how 
 its eradication was to he accomplished, but (hero was a general 
 hdief and hope that \>\ improving the sanitary conditions the disease 
 
 234 
 
YELLOW FEVER. 235 
 
 here could be greatly decreased, and possibly in the course of a 
 number of years gradually gotten rid of, as has been the case in the 
 cities of the United States. But no one, I think, who knew anything 
 of yellow fever practically would have ventured to predict that 
 much could have been done in this line in the course of three years. 
 
 In Habana the government went vigorously to work, rapidly 
 organizing street cleaning, disposal of garbage, and the cleaning of 
 premises. In a very few months the streets were as clean as those 
 of any modern city and the garbage regularly disposed of. But the 
 internal sanitation of houses and the organization of the sanitary 
 department for the reporting and control of contagious and infectious 
 diseases, and similar matters, took a longer time. 
 
 In the early part of 1899, the first year of the military occupation, 
 very little yellow fever occurred. The preceding five years had 
 been years of war, and for the last few months the American blockade 
 had practically put an end to immigration into Habana, and the 
 nonimmune population was pretty well exhausted, so that there 
 were few left capable of having this disease. In January, there was 
 one death; in February, none; in March, one; in April, two; in 
 May, none; in June, one, and in July, two. That is, in the first 
 seven months of 1899 there were only seven deaths from yellow 
 fever. The military governor of the city, Gen. Ludlow, felt sure that 
 the measures which were being taken had pretty well eradicated it. 
 
 But about the 1st of August, Spanish immigration began to pour 
 into Habana, and between August and December some 12,000 
 immigrants arrived in the city, about 60 per cent of whom settled in 
 Habana. This at once started up yellow fever, and by December of 
 1899 we were having a severe winter epidemic. This continued 
 right along through 1900, during which year we had a very sharp 
 epidemic, having in all some 1,400 cases. 
 
 The general sanitary conditions had improved, as indicated by 
 the falling death rate, in a very satisfactory manner; but our work 
 was evidently having no effect upon yellow fever. This disease was 
 under control everywhere else in the island, but the principal means 
 of reducing it, the deportation of the nonimmune population, so 
 successful everywhere else, was not practicable in Habana. 
 
 By the beginning of 1901 the sanitary department was pretty 
 well satisfied that ordinary sanitary measures were having no imme- 
 diate effect upon yellow fever. The city during the year 1900 was 
 as clean and in as good sanitary condition as it was possible for labor 
 to make it, and affairs could not be gotten into better condition until 
 after the completion of a sewer system. 
 
 In the summer of 1900 a commission of Army medical officers 
 headed by Maj . Walter Reed, United States Army, had been sent to 
 Cuba for the investigation and study of yellow fever. Due to the 
 financial assistance given by the military governor to this commis- 
 sion, they were enabled to experiment on the human subject. They 
 took up the theory advanced by Dr. Carlos Finlay of Habana, in 
 the year 1880, that the Stegomyia mosquito was the sole means of 
 the transmission of yellow fever. Dr. Finlay had maintained this 
 theory for some 20 years, and had done considerable experimental 
 work in this direction. 
 
 The commission, through elaborate and careful experimentation, 
 proved this to be correct, and in February, 1901, Dr. Reed read a 
 
236 
 
 paper before the International Sanitary Congress, in Habana. giving 
 the results of their work. This idea was so new and so entirely 
 Contrary to all former theories on the subject, and. apparent 1 
 all former experience, that the paper was received with scant belief. 
 I myself had seen the work, and was convinced that the mosquito 
 could convey yellow fever, but I was hardly prepared to believe that it 
 was the only wa . <\ the ordinary way, of conveying the disease. 
 
 But all ordinary sanitary measures for the preceding two \< 
 had been flat failures. Yellow fever at the heirinning of !!()] was 
 about as bad as it had ever been in Habana at that time <>f the year. 
 The city was infected in every part, and there was present probably 
 the largest nonimmune population that had ever In-fore been in 
 Habana. 
 
 1 had very little hope of accomplishing much; it seemed to me that 
 even if the mosquito did convey yellow fever, he could not be gotten 
 rid of, and, apparently, from all past experience, the mosquito 
 not the only way, or even the principal way, of conveying the disease; 
 but, as he evidently could convey the disease, it was our duty t<> 
 take precautions in this direction. 
 
 The military governor readily granted the necessary appropriation 
 and authorized the employment of as large a force as needful tor m<s- 
 quito work. Work was commenced on this line February 4, 1901, 
 and pushed hi every direction. The results soon began to be appar- 
 ent. In January there were seven deaths from yellow fever; in Feb- 
 ruary, the first month of mosquito work, five death-: in March, one 
 death; none in April, May, or June; one in July; two in August ; and 
 two in September, and for the nine months following September, 
 
 1901, not a single case nor a death has occurred from this disease. 
 This result convinced the sanitary department that the mosquito not 
 only could convey yellow fever, but that it was the ordinary way, 
 and the only way, at least in Habana, for the conditions in Habana 
 during 1901 were as favorable for a yellow fever epidemic as they had 
 ever been. The city had the largest nonimmune population, proba- 
 bly, that it had ever contained. Infection was scattered in every 
 part of the city; not only so, but the small towns surrounding the 
 city were thoroughly infected, and were constantly sendi: 
 
 into the city. We continued the same sanitary measures that had 
 been taken during the preceding year, and which had not had the 
 slightest effect upon the march of yellow fever; but, in addition, we 
 we took measures looking to the Stegomyia mosquito as the means 
 of conveying the disease. Immediately after the adoption of th->e 
 measures, yellow fever began to decrease, and by September had 
 been entirely eradicated from the city. 
 
 The demonstration is the more effective in Habana from the fact 
 that in all other cities of North America yellow fever laatfl f<>r a 
 greater or lesser number of years, and then disappears from natural 
 causes, to reappear again when conditions are favorable. In Habana 
 the conditions have been different. For 150 years yellow fever has 
 been constantly present in the city. From September, 1901, to July, 
 
 1902, not a single case nor a death has occurred. In the 150 } 
 referred to, not any year, probably, can be picked out in which (hir- 
 ing the same period there were less than 100 deaths. 
 
 Tliis.it seem- t" me, is a practical demonst rat ion, given in the only 
 endemic focus for yellow fever in North America, and in a year when 
 
YELLOW FEVEB. 237 
 
 the conditions were most favorable for the development of the disease, 
 of the fact that the Stegomyia mosquito is the only method of trans- 
 mitting it a fact proved by the Army commission. 
 
 Under Army administration the death rate in Habana has de- 
 creased in a marked degree. In 1898, the number of deaths was 
 21,252, giving a rate of 91.03; in 1899, the first year of our occupa- 
 tion, we had 8,153 deaths, giving a rate of 33.67; in 1900, we had 
 6,102 deaths, giving a rate of 24.40; in 1901, we had 5,720 deaths, 
 giving a rate or 22.11 ; for the first four months of 1902 there occurred 
 1,896 deaths, which if kept up for the year would give 5,688 deaths, 
 a rate of 20.68 for the year. 
 
 Thus it can be seen that under the military government, in a little 
 over three years the death rate was reduced from 91.03 to 20.68. 
 The latter rate would be a favorable one for the better class of cities 
 in Europe or the United States. And this has come about without 
 making any permanent sanitary installations, such as sewage. The 
 city was kept as clean as it was possible for labor to make it, with 
 regard to trie streets, disposal or garbage, and the interior of the 
 houses. But every house in Habana, somewhere under the house, 
 still has a cesspool, the flow from which sinks into the surrounding 
 ground, and as this has been going on for 400 years, the ground itself 
 is as thoroughly saturated with organic matter as is possible. 
 
 The authorities had hardly hoped for such marked improvement 
 until this system of cesspools has been done away with by a good 
 system of sewage. But apparently the condition referred to has no 
 very great effect upon the general health of the city; the improve- 
 ment has come about from a careful street cleaning, disposal of garb- 
 age, internal sanitation of houses, and rigid control of infectious and 
 contagious diseases. 
 
 Our work down here has been a useful lesson in municipal sani- 
 tation. The same thing could be accomplished by any community 
 anywhere else, if they were willing to spend money and labor upon 
 it. No elaborate machinery of any kind is necessary; merely men 
 and brooms. 
 
 The primary object of the war with Spain was the liberation of 
 Cuba from Spanish domination, but, at the same time, the United 
 States had hoped to accomplish a good deal in improving the sani- 
 tary condition of the island. In this she has succeeded beyond her 
 utmost expectations, and the results in Cuba have been a new de- 
 parture in military conquest. The only other people who bear 
 comparison with us in attempting to improve the sanitary condi- 
 tions of a tropical country are the English, and neither in Jamaica nor 
 in India have they been very successful in this respect. 
 
 Much to our surprise, we find that not only can a native city like 
 Habana be made as healthy as the better class of cities in the United 
 States, but that our own troops, with proper care, thrive just as 
 well in the Tropics as they do in the Temperate Zone. With the 
 troops, the health conditions have steadily improved, until at the 
 evacuation of Cuba the health rate was better among them than the 
 average of troops in the United States. 
 
 Our first year in Cuba, 1898, with an average of 8,345 men, we 
 had a death rate from disease of 67.94 per thousand. The health 
 conditions steadily improved during the four years of our occupation, 
 and for the last three months of 1902, with an average strength of 
 
238 YKl.LOW FHVEK. 
 
 ' inon, wo had a death rate from disease of 1.70 per thousand. 
 Tliis means that the firM year of our life in the Tropics \\ e lost 07 
 men out of every thousand, from disease; the last year of our slay, 
 we had profited by our experience to such an extent that \ve lost 
 only 7 men per thousand. 
 
 From our experience in Cuba, several useful lessons can he de- 
 dueed. We find that the native in the Tropics, with the same sani- 
 tary precautions that are taken in the Temperate Zones, can he just 
 as healthy and have just as small a death rate as the inhabitants of 
 the Temperate /one: that to brini: this about , no elaborate machinery 
 of any kind is needed: that it can be attained by any community, 
 no matter how ooor. if they are willing to spend sudicient labor in 
 cleaning, and observing well-known rules with regard to di-< 
 that the North American Anglo-Saxon can lead juM as healthy a 
 life and live just as long in the Tropics as in the Tniled Stale-. 
 
 But by far the most important sanitary lesson is with regard to 
 yellow fever that this disease is only conveyed by the stegomyia 
 mosquito; that the disease can readily be eradicated, even when ii 
 has gotten a lirm hold, and easily kept from establishing itself by 
 taking measures looking to the mosquito as its can 
 
 1 look forward in the future to a time when yellow fever will ha\> 
 entirely disappeared as a disease to which mankind is subject, for I 
 believe that when the yellow fever parasite lias once become extinct 
 it can no more return than the dodo or any other species of animal 
 that has disappeared from the earth. 
 
 Very respectfully, W. C. GORI;.\>. 
 
 Major, Medical Corps, United States Amu/. 
 
 Brig. Gen. LEONARD WOOD, 
 
 United States Army, Washington, D. C. 
 
PART V A FEW GENERAL DIRECTIONS WITH REGARD TO DESTROY- 
 ING MOSQUITOES, PARTICULARLY THE YELLOW-FEVER MOSQUITO, 
 
 By W. C. GORGAS, 
 
 Colonel, Medical Corps, United States Army} 
 
 As this article is not intended for the reading of people who have 
 given any particular attention to the facts at present known of the 
 way in which the mosquito carries disease from one person to another, 
 I think it best to briefly call attention to the leading points in our 
 present knowledge of this subject. 
 
 Malaria and yellow fever are the two great diseases with which the 
 mosquito is concerned. They are by far the most important diseases 
 in the tropical countries of the Western Hemisphere, and play a great 
 part in the sickness of the southern part of the United States. Up to 
 25 years ago it was universally believed that malaria was caused by a 
 gas, or miasm, arising from the decomposition of dead vegetable mat- 
 ter in hot countries, but about that time a French army surgeon in 
 Algeria, Laveran by name, noticed that if he looked sufficiently care- 
 fully with his microscope, in the blood of persons suffering from 
 malaria, he could almost always find a very small animal parasite. 
 This little, living being got into the blood in some way, Laveran did 
 not know how, fed upon the red blood corpuscles, and was apparently 
 the cause of the disease which we call malaria. Laveran's discovery 
 was a great advance in our knowledge of the disease, and it was 
 gradually accepted by all the medical world. 
 
 A careful search was made for the parasite by many investigators, 
 but it could only b.e found in the blood of human beings suffering from 
 malaria. Where else it was bred and how it got into the blood of 
 man no one could find out. About this time it was discovered by an 
 English army surgeon, Dr. Manson, that a small worm the Filaria 
 sanguinis Jiominis was introduced into the body by the bite of a mos- 
 quito. (This worm causes the disease among human beings known as 
 filariasis, and to it are due the enormous and unsightly swellings of 
 the legs and other parts of the body seen by our people in Cuba and 
 the Philippines, it is, however, a disease very rarely found in the 
 United States, and not of much importance to us. I only mention it 
 here in connection with my story of the mosquito.) 
 
 About 15 years after the discovery of Laveran that malaria was 
 due to an insect in the blood, and of Manson, that a certain worm 
 which caused disease was introduced into the human blood by the bite 
 of a mosquito, another great English army surgeon, Ronald Ross, 
 
 * Washington, Government Printing Office, 1904. 
 
240 YII.LOU 
 
 discovered that the malarial para-it e was found in a certain species of 
 mosquito the anopheles after the insect had bitten a human being 
 suffering from malaria. With his microscope ho followed the life 
 history of this parasite, from the stomach of the mosquito, through 
 the vails of the stomach into the mosquito's b<>d\ , and finally im 
 sah'vary glands. In the saliva of the mosquito, the little organism 
 was found in large numbers, and when biting man, for the purpose of 
 getting blood, the mosquito injects her fatal saliva, just as does the 
 rattlesnake when he bites. This discovery of Dr. Ross \\as demon- 
 strated in the most positive manner. 
 
 An Italian living near Rome, in Italy (malaria is verv bad in the 
 neighborhood of Rome), while sutlering from a malarial attack was 
 'i by an anopheles mosquito. This mosquito was thou taken to 
 London, England, whore they have no malaria, and a healthy young 
 man, who had never had malaria, was bitten by her. In a lew days the 
 young man had a well-marked attack of malaria, with the u-ual s 
 tom-, and the malarial parasite was seen by the microscope circulat ing 
 in the blood of the patient and feeding upon the red blood corpu 
 of his blood. And, again, men were taken, put into house-, screened 
 so t hat mosquitoes could not get in, and spent weeks in this unhealthy 
 part of Italy without getting sick. Yet this particular part of Italy 
 is considered so unhealthy that during the summer season neither 
 native nor foreigner, who can avoid it, spends a night there. 
 
 A night spent in the Campania used to be thought a certain way to 
 contract malaria, the idea being that the foul air from the ma 
 caused the disease. Yet it is now seen that entirely unacclimated men 
 can breathe this air with safety, provided onlv that they live in screened 
 houses and are not bitten by mosquitoes. These and similar fact s n m- 
 vinced the scientific world that the malarial organism gets into the 
 blood of the human being through the bite of the anopheles mosquito, 
 and in no other way. 
 
 Before the year 1900 it was universally believed that yellow f. 
 was carried from person to person and spread generally by a germ 
 which up to that time had not been discovered. The germ v 
 posed to travel from person to person by contact with those sick of the 
 disease, or by means of clothing or other articles which had been near 
 the sick, and its development was believed to be greatly favored by all 
 conditions which increased filth. There were a good many fact s in t he 
 spread of the disease which were difiicult to account for under t his sup- 
 position, but nevertheless it was the best explanation possible, and, 
 as I said, was almost universally accepted, both by physicians and 
 people generally. 
 
 During the year 1900 the Army of the United States had entire 
 control of Ilabana, at that time the great center of yellow lexer for 
 the world. An excellent opportunity for investigating the di 
 therefore existed. The Surgeon General of the Army sent to I la ban a 
 a board of Army medical officers for the purpose of in\ -li. ating 
 yellow fever. This board was made up of the following Army do. ; 
 Dr. Reed, the president, and Drs. Carroll, Agramonte, and La/car. 
 After much investigation they determined to study the relation of the 
 mosquito to yellow fever. Their attention was called to this matter 
 by tne part that the mosquito had already been pro vet I to pla 
 malaria and lilariasis, as mentioned above, and also by certain facts 
 known in the history of yellow fever epidemics. Dr. Hnlay, a prom- 
 
YELLOW FEVER. 241 
 
 inent physician of Habana, reasoning from certain peculiarities of 
 yellow fever and from experiments which he made, had maintained 
 ifor many years that a certain kind of mosquito in Habana, the stego- 
 myia, was the cause of yellow. fever.,. Jout. he had not been able to 
 ; prove it. 
 
 DIRECTIONS WITH REGARD TO DESTROYING MOSQUITOES. 
 
 The Army board of which Dr. Reed was president recognized that 
 in Cuba, where they did their work, it would have to be entirely 
 evident that the men experimented upon could not geV f yellow fever 
 accidentally in " Habana, :or any where ,ejse, 'but only, .if at all, in the 
 t course of the experiment. They therefore took a piece of unoccupied 
 'ground about-6 miles from Habana and built -there a camp of material 
 which could not have been infected with yellow fever. 'They then 
 got men who had never suffered from yellow fever and placed them in 
 these tents. It -was known that -if a man exposed to v el-low, lever was 
 going to 'have it the disease' would develop <m-43s tkmi-sfK"rl'ays,*aiid 
 if he passed through six days safe and sound he was known to have 
 escaped that particular exposure. 
 
 The board therefore argued that if they kept their men in this camp 
 for a period of two weeks they would be safe from any exposure 
 which might have occurred before their coming to the camp. They 
 also had to provide means which would insure their men not leaving 
 the camp, contracting the disease outside, and thus bringing infection 
 into the camp. This was done by a military guard, who allowed no 
 one to go out or come in without Dr. Reed's permission. Things were 
 now so arranged that if a mosquito was allowed to bite a man, and 
 yellow fever developed, the board could be certain that the yellow 
 fever was due to the bite of the mosquito alone. They did a great 
 deal of experimenting here before they worked out all the details of 
 the way in which the mosquito actually conveys yellow fever. They 
 finally found out that if a female mosquito of one particular species, 
 the stegomyia, was applied to a yellow-fever patient in the first 3 
 days of his sickness, and then kept from 10 to "20 days and allowed 
 to bite a human being who had never had yellow fever, he would 
 very generally develop the disease within 6 days after the bite. 
 
 They also found out that this same man, before he had been bitten 
 by the yellow-fever mosquito, could sleep in the bed in which a patient 
 had died of yellow fever, could be covered with a black vomit from a 
 yellow-fever patient, or be exposed to the emanations from yellow 
 fever in any other way, and as long as he was kept safe from the bite 
 of the mosquito he would not have yellow fever; but this same man, 
 after all this exposure, if afterwards bitten by an infected yellow-fever 
 mosquito, would very certainly catch the disease. I think it would be 
 interesting to give some of the details of the work by which this great 
 discovery was demonstrated. 
 
 They had a little frame building built in this camp furnished with 
 jars and the necessary simple material for breeding mosquitoes. The 
 building was carefully screened and guarded, so that mosquitoes could 
 not get in nor out. Eggs of this particular species of mosquito were 
 obtained and hatched in one of the jars. A female mosquito was 
 taken from the brood thus hatched. The male mosquito will not bite, 
 and can readily be distinguished from the female with a magnifying 
 79965 _S. Doc. 822, 61-3 16 
 
2 4'2 YKi . i i:. 
 
 glass* by the fact that the male has very heavy feathery feelers (anten- 
 na) growing from his head. The female mosquito selected was put 
 into a small glass tube, stoppered with a little cotton, so that she could 
 get air freely hut not escape, taken to 1 labanu. nlaced on the hand of a 
 patient in the first three days of an attack of yellow fever, and allowed 
 to fill herself with blood. She was then brought back to her former 
 home, placed in a large glass jar, and allowed to digest- the blood she 
 had obtained. The jar, covered with a piece of mosquito netting, had 
 in it a small saucer with a little water, and a lump or white sugar was 
 also provided. Under these conditions the mosquito was furnished 
 with all the necessities of life. 
 
 So confident were the men in charge of the mosouitoes that I h 
 known them to put their hands in the jars and let trie mosquitoes 
 upon them, up to the fifth or sixth day after the mosquito had bit ten 
 a yellow-fever patient. The mosquito, you recollect, can not convey 
 the disease till from 12 to 20 days have passed from the time of her 
 biting the yellow-fever case from which she becomes infected. 
 
 On the other hand, I once saw a party of 12 or 15 doctors in the 
 mosquito room one day, when the mosquito-bar covering of the jar 
 accidentally came off and the insects escaped into the room. These 
 doctors had come from other countries to investigate the subject, and 
 were not then convinced that the mosquito carried yellow 1 
 Still, they did not care to put the matter to a practical test in their 
 own persons, and got out of the room so rapidly that the wire-screen 
 door was broken down during their exit. It happened that the inos- 
 guitoes in this jar had never bitten a yellow-fever patient and were not 
 infected. 
 
 After the mosquito had been left in this condition for from 10 to 20 
 days, it was known that her saliva was capable of transmitting the 
 disease. When she was wanted for the purpose of giving some hoc ly 
 yellow fever, a man would take a glass tube, slip his hand under the 
 mosquito netting, put the mouth of the tube over the mosquito, and 
 then fill the mouth of the tube with a cotton stopper, as above 
 described. She would then be taken to the man to whom it was 
 desired to give yellow fever and who had bravely volunteered for the 
 purpose, the cotton stopper taken out, the tube turned upside down 
 with its mouth resting on the skin, and the mosquito allowed to set tie. 
 She would then introduce her biting apparatus and slowly fill her- elf 
 with blood. But before she fills with blood she injects her saliva into 
 the wound, just as does the snake in biting. It is this injection of the 
 saliva that causes the swelling and the burning sensation that is felt 
 at the point where the mosquito bites and which lasts some time after 
 she has finished. The injection of the irritating saliva probably has 
 the effect of making it easier for the mosquito to get blood. 
 
 Now, it will be remembered that this man who was bitten had been 
 kept in the camp for two weeks before he was bitten, and isolated in 
 such a way that he could not possibly have contracted yellow fever. 
 There were 30 or 40 men in the same camp under exactly the same 
 conditions. Three or four days after he was bitten by the mosquito 
 he developed a well-marked case of yellow fever, although everybody 
 else in the camp remained well. Dr. Reed and his fellow workers 
 therefore very naturally believed that that particular mosquito 
 the man yellow fever. They repeated this test 12 or 15 different times 
 with the same result. NoSody else in the camp had yellow fever. 
 
YELLOW FEVER. 243 
 
 Always within six days after the bite of the mosquito known to be 
 infected the man experimented upon had yellow fever. 
 
 To show how a house could become infected with yellow fever the 
 board conducted the following experiment: They built a large room 
 and screened it so that mosquitoes could not get in or out. (When- 
 ever 1 use the word "screen" here I mean the ordinary wire netting or 
 mosquito bar.) The purpose is of course to leave a perfectly free cir- 
 culation of air, but to have the meshes of the wire or mosquito bar 
 netting so small that a mosquito can not get through. They then 
 divided this room into two parts by a wire netting extending from top 
 to bottom, so that a mosquito could not pass from one side to the other, 
 but at the same time leaving the circulation of air entirely free, the 
 desire being to show that if it were any miasm, or emanation, or germ 
 floating in the air which caused yellow fever it could freely pass from 
 one side to the other of this netting, and that both rooms, as far as 
 these emanations were concerned, were in the same condition. 
 
 Now, to show that the building was uninfected, four men were put 
 in it who had never had yellow fever, two sleeping on each side of the 
 wire netting. They were left there for two weeks and remained per- 
 fectly well. Reed then said, "I am now going to infect the room on 
 one side of this wire netting with yellow fever and not infect the other 
 side." He took the two men out of one side and liberated a half 
 dozen infected female Stegomyia mosquitoes on this side. The two 
 men still slept and lived on the uninfected side. He then put a 
 volunteer on the side with the mosquitoes and left him there for half 
 an hour, took him out, and within six days this man developed yellow 
 fever, the two men on the other side of the room remaining well. 
 
 He therefore argued that, as the two men who had been for so long 
 a time on one side of the wire netting and remained well were breath- 
 ing the same emanations, and the only difference was that there were 
 mosquitoes on the infected side to which the man had been exposed 
 for half an hour, it was very good proof that the mosquito was the 
 factor which gave yellow fever. He then said, "Now that I have 
 shown you a nouse infected with yellow fever, I will demonstrate 
 how it can be disinfected and rendered safe." He then caught his 
 half dozen mosquitoes, bottled them up and put them back into their 
 jars, and announced that the building was entirely safe and unin- 
 fected, put the two men back into the side which had been infected, 
 and the four continued to sleep and live as safely in these quarters 
 as they had before the infection. 
 
 The board had another room built and got ah 1 sorts of material 
 infected by yellow-fever patients from the hospital, clothing worn by 
 patients at the time they died of yellow fever, such as mattresses on 
 which they died, soiled in every possible way, pillows and pillowcases 
 saturated with black vomit, and blankets over which basins of black 
 vomit had been poured; in short, material infected by yellow fever in 
 every possible way that could be thought of. All this material was 
 placed in the room, which was made close and tight with very little 
 ventilation, so as to make the conditions most favorable for what was 
 ordinarily considered the best way of insuring the spread of yellow 
 fever. Volunteers who had never had yeUow fever were placed in 
 this room, lived and slept there for two weeks at a time, wore this 
 clothing, slept on these mattresses, under these sheets, and yet not a 
 single case of yellow fever was developed from this contact. The 
 
244 YKLLOU 
 
 men who hail undergone this exposure were taken out and -kept tor 
 weeks 30 as to in-ure that they had not contracted yellow fever 
 from the exposure, and then bitten by infected mosquitoes. They 
 always got yellow fever from the bite of the mosquito, hut never in 
 any other way. 
 
 At this time the military authorities had had entire control of 
 Habana for about two years. An Army doctor had been placed in 
 charge of the health department and given the mean- and power to 
 do \\hat he thought jno>t likely to free the city from yellow fever. 
 Yello\\ lV\cr in Ilahana wa- a disease like consumption in OalveMon 
 w Orlean> always there, and always One of tne principal oauses 
 of death in the city. And this had been the state of all'airs a- |o: 
 anything had been known with any accuracy, either about yeflow 
 fever or about the health conditions of Habana; and the-e 'tiling 
 were pretty accurately known for more than a hundred year- imme- 
 diately preceding the time I refer to. When we organized our health 
 department, we believed, as did everybody el-e, that yellow fever was 
 caused by filth, dirt, and general insanitary conditions, so we went 
 to work doing our very best to correct these conditions. With these 
 efforts Habana very rapidly became a healthy city, as much so as 
 many of our large cities in tne United States, but yellow fever did not 
 seem to be affected. 
 
 The second year of our control yellow fever was very severe in 
 Habana, but did not attack the native Cuban because he was generally 
 acclimated. Only the foreigner, therefore, was subject to the disease. 
 During the year 1900 many of our prominent American civilians and 
 military officials died of the disease, and the very cleanest and h-t 
 parts of the city and the people who lived best and took the be>t 
 of themselves were most affected. When the Army Board published 
 their discovery to the world the health department of Habana r< 
 nized that it and all the rest of the world had been on the wrong 
 track with regard to yellow fever, and they determined to change 
 their methods and attack the mosquito as the cause of the disease. 
 
 They had been convinced by tne work of the Army board that a 
 human being could only get yellow fever by being bitten by a par- 
 ticular kina of mosquito the stegomyia which had previously 
 bitten a man suffering from yellow fever. They therefore arranged 
 that as soon as a man sickened with yellow fever employees from t he 
 department went to the house and screened it with wire nettii. 
 that those mosquitoes that were in the house could not get out and 
 those outside could not get in. A smudge was then made of sulphur, 
 tobacco, or insect powder, as host suited to the circumstances, in the 
 affected house, and in all those immediately around it. with the 
 intention of killing all moscjuitoes present, liy this method it was 
 hoped that both the mosquitoes that had bitten the man and ca 
 the disease would be killed, and also those that had bitten the man 
 after he was taken >ick. and had thus become themselves infected 
 and able to spread the disease. For the purpose of doinir this 
 screening a building was arranged very much like a fire stat ion in ne 
 of our cities, where wagons, wire screens, carpenters, and men with 
 material for making a smudge, were always kept on duty, who pro- 
 ceeded at once to the place where a yellow fever case was reported to 
 exist. 
 
YELLOW FEVEIt. 245 
 
 This method was very successful in its results. After its adoption 
 very few cases occurred where the disease spread from the person 
 infected to others in the neighborhood. It was also determined to 
 destroy as many as possible of the yellow fever mosquitoes in the 
 city. It was known that the female mosquito had to have water 
 on which to lay her eggs, and that these eggs could not hatch without 
 water; that this water had to be very quiet and well protected for the 
 hatching process to take place ; that the eggs took about three days 
 to hatch; that after hatching the insect had to live the life of a fish 
 in this water for five or six days. During this fish stage they are 
 known as larvae, and are well known to everybody in the South, for 
 they are nothing but the common wigglers always found in standing 
 rain water during the summer months. Now, while in this wiggler 
 stage the insect has to have air, and for this purpose must every 
 little while come to the surface. At the end of five or six days the 
 wiggler changes into the full-grown mosquito. 
 
 It is known that this particular species of mosquito the stegomyia, 
 or the yellow fever mosquito lives and breeds almost altogether in 
 houses and in their immediate neighborhood, and does not leave the 
 house for any great distance. With this knowledge of its life history, 
 the department found it easiest to destroy the mosquito in its wiggler 
 stage, and the most useful means in this direction they found to be 
 the doing away with all the little deposits of water in and near inhab- 
 ited houses, which the wiggler must have in order to develop into the 
 mosquito. The methods herein described were not settled upon, as 
 might appear from this account, all at once and at the beginning, but 
 many other methods of waging war against the mosquito were tried, 
 found impracticable, and dropped. 
 
 With the object of doing away with the breeding places of the 
 yellow-fever wiggler, all the houses and yards of Habana were carefully 
 examined and all tin cans, empty bottles, and trash of the same kind, 
 which were generally found filled with rain water and full of yellow 
 fever mosquito larvae, were carefully carted off. Then the necessary 
 openings in all cisterns were covered with mosquito netting, so that 
 the mosquitoes could not get in to lay their eggs. Among the poorer 
 people, who had only barrels and other similar receptacles for rain 
 water (and in Habana every family had something of this kind), the 
 health department arranged these necessary receptacles for them by 
 placing a wooden cover on the barrel, leaving a hole in the center of 
 this cover for the entrance of water, and covering the hole with wire 
 netting, so that mosquitoes could not get in. To enable them to draw 
 off the water without opening the barrel a cheap wooden spigot was 
 placed in the lower part. 
 
 Now, from the peculiarity of the wiggler, that he has to come to the 
 surface of the water every few seconds to get air, if we put anything 
 on the surface of the water that prevents him getting this air, he 
 drowns just as certainly as a man would who is kept under the water. 
 Ordinary kerosene oil, a tablespoonful or two to a cistern, spreads 
 over the surface of the water and kills the wiggler in this way. He 
 can not break through the scum of oil to get air. But oil very rapidly 
 evaporates and has frequently to be renewed. So oil was only used 
 in Habana where no other method was successful. The privy pits in 
 all the houses there were in the center of the court, covered generally 
 with heavy flagstone. These pits, not being in general accessible to the 
 
246 YKLI.OW F! 
 
 inspectors, had to be treated with oil. Once a month a couple of 
 ounces of oil were poured into the pipes leading to the pit-. 
 
 To insure that these methods and ordinances were carried out. the 
 city was divided into districts of about a thousand houses each, BO 
 that an inspector would get over each district in the course of a inont h, 
 inspect in*: at the rate of about 30 hou-c- a day. This inspector 
 had with him two men who used the oil as ahove described. lie had 
 with him printed blanks on which he entered the condition of the 
 premises as to w idlers. These reports were turned in every night 
 to the office of the health department and wero consolidated from day 
 today. At the end of the month we could therefore tell the condition 
 of Habana as to wigglers. At the first report on this subject (I think 
 in March, 1901) we found that we had in Habana in the neighbor- 
 hood of 26,000 different water deposits which contained w idlers. 
 most of them of the yellow-fever variety. 
 
 After once going over the city and carefully explaining to the 
 people the dangers of allowing wigglers on their premises, and after 
 having fixed up for the poor all the water barrels which they were 
 obliged to keep for holding their ram water, the mayor of the city 
 issued an ordinance stating that anybody who bred wigglers on his 
 premises would be fined $10. These two methods of destroying 
 yellow fever mosquitoes, namely, that of killing the grown mosquito 
 in the neighborhood of every yellow fever patient with a smudge and 
 of looking after the wigglers hi all rain water deposits about the house, 
 were steadily enforced during the year 1901. The results were bet t er 
 than we had dared to hope. Few cases occurred in which yellow 
 fever spread from a case cared for in this wav. Yellow fever rapidly 
 decreased, and on September 28, 1901, the last case of yellow 1 
 occurred in Habana, and since that time now more than two years 
 not a single new case has developed in the city. 
 
 There were still, of course, a great many yellow fever mosquitoes 
 in Habana, but these methods of destroying the wigglers had greatly 
 decreased the numbers of mosquitoes. The report of January, 1 
 after about ten months of this mosquito work, showed that within 
 the city limits less than 300 premises had wigglers upon them. This 
 I think a very fair measure of the results accomplished by one year's 
 work, namely, that the number of deposits containing wigglers had 
 been decreased from about 26,000 to about 300. 
 
 I think it is evident that tne disappearance of yellow fever from 
 Habana was due solely to this mosquito work. Remember that it 
 was an every-day disease in Habana, and had been so for more than 
 a hundred years, just as consumption is in' New Orleans, a city of 
 about the same size as Habana. Now, if some method should be 
 adopted against consumption in New Orleans, and systematically 
 put in operation in the city against that disease, and at the end of a 
 year it could be shown that no new cases of consumption were occur- 
 ring in New Orleans, and at the end of two years and a half it could 
 be further shown that under the continuance of the same measures 
 the disease had entirely disappeared from the city, and no new cases 
 had occurred, I should think that we would all be at once convinced 
 that the disappearance of consumption from New Orleans was due to 
 the efficacy of the measures adopted. 
 
 In Habana, even now, a case or two of yellow fever comes in every 
 month from Mexico and other infected regions which have a con- 
 
YELLOW FEVER. 247 
 
 siderable trade with Habaiia. The ships are carefully inspected by 
 the quarantine authorities, just as is done in our country. If a 
 
 Eerson sick of yellow fever, or suspected yellow fever, is discovered, 
 e is landed at the city wharf, in the heart of the business district, 
 placed in an ambulance, carried to the yellow fever hospital, which 
 is well within the city limits, and treated there. The only precau- 
 tion taken is to see that Habana mosquitoes do not get an oppor- 
 tunity to bite him. The authorities at Habana thoroughly believe 
 that if they can prevent mosquitoes from biting a yellow fever patient 
 the city will be entirely safe in handling him and taking care of him. 
 
 In 1901, during the height of the yellow fever work at Habana, a 
 town of about 5,000 inhabitants, some 12 miles from the city, became 
 badly infected with yellow fever. This town, Santiago de las Vegas, 
 was practically a suburb of Habana, and the business communication 
 with the city was very intimate. We found that people who were 
 working at Santiago de las Vegas were constantly getting sick of 
 yellow fever, and as soon as they found themselves sick would come 
 into Habana to the homes of their friends and relatives to be taken 
 care of. In order to do away with this source of danger, a large force 
 of men was put at work at Las Vegas, on the lines above described. 
 The whole town was systematically gone through from house to house, 
 and at the end of about six weeks of this work the disease was entirely 
 wiped out and we had no more trouble with infection from Las Vegas. 
 1 mention this as showing the possibility of taking a small town and 
 getting rid of the disease rapidly by mosquito work. 
 
 We had other mosquito work going on in the suburbs of Habana, 
 among the truck gardens and irrigated fields where grass was grown. 
 But the yellow-fever mosquito does not breed to any great extent in 
 such places, and I do not think this work had much effect upon the 
 yellow fever. But malaria, as I have above mentioned, is also carried 
 exclusively by a mosquito named the " anopheles." Now, this malarial 
 mosquito likes to breed in places where there are little puddles of 
 water, cow tracks, horse tracks, and similar depressions in grassy 
 ground, and the work in the suburbs had its principal effect upon this 
 mosquito. It was not desirable to stop irrigation, as the livelihood of 
 all these small farmers depend upon it, but by taking advantage of 
 the fact that a deposit of water had to remain undisturbed at least 10 
 days to breed a mosquito, we could allow them to irrigate freely, pro- 
 vided the water did not remain longer than a week. The health de- 
 partment had all this area arranged with shallow, superficial ditches 
 which would not interfere with irrigation, but would allow rapid 
 drainage when the water was taken off. All pools and puddles which 
 had no economic use were kept drained, and ditches and streams kept 
 clean of grass and obstructions. 
 
 After once getting the country cleaned up at public expense, and 
 the matter explained to the farmer, he was fined in the same way as 
 the householder in the built-up portion of the city, if wigglers were 
 discovered on his premises. While I do not think that these measures 
 aided us particularly in yellow fever, they had a marked effect upon 
 malaria. In 1900, the year before the mosquito work commenced, we 
 had in Habana 325 deaths from malaria. During 1901, the year in 
 which mosquito work was commenced, we had 151 deaths from 
 malaria. In 1902, the second year of mosquito work, Dr. Carlos 
 Finlay, the health officer of Cuba, reported 77 deaths from malaria in 
 
248 : ^' 1'i 
 
 Habana, and up to the 1st o!' No\ ember in 1 !():>. the third year of 
 mosquito work. Dr. Finlay reported l."> deaths from malaria. 
 
 This mosquito work of the Hnhana health department, 1 hold, 
 demonstrates the practicability of eliminating in the Tropics the two 
 diseases malaria and yellow fever, and I believe if the attention of the 
 people at large in our own country were generally attracted to the 
 danger of transmitting disease by the mosquito, and the practicability 
 of destroying them, we could very generally eliminate these two 
 diseases from our own country. 
 
 And now to the reason for writing this article. I thought an account 
 of the relations of mosauitoes to disease, given in simple terms, readily 
 understood by t hose wlio are not doctors, might held people generally 
 in making aii attempt to get rid of mosquitoes, each man about his 
 own house. I will now proceed to make suggestions in this direction. 
 And in order to make myself entirely clear will repeat a good deal, 
 and enlarge upon what I have already said. 
 
 The work of the Army medical board of which Maj. Walter Keed 
 was president, showing that a particular species of mosquito was the 
 only means of transmitting yellow fever, is now pretty generally 
 accepted by all the scientific world. Based upon this knowledge, 
 certain methods were adopted by the Army medical officers in Haba n a , 
 Cuba, which resulted in eradicating yellow fever from that city. 
 During the fall of 1903 yellow fever was introduced from Mexico and 
 became quite widely spread through western Texas. It is thought 
 that a few general rules, based upon the knowledge acquired by tho 
 Army board and the experience of the Army medical officers in I labana. 
 may be of use in assisting individuals and towns in freeing themselves 
 from infected mosquitoes during the present winter and coining 
 spring. Otherwise, it seems highly probable that yellow fever, at 
 some point in Texas, will again develop as the warm weather comes on. 
 This would come about from the fact that the infected mosquito can 
 very readily live through the winter in the latitude of Laredo. 
 
 As yellow fever can only be spread by a particular species of mos- 
 quito, it follows that if there are none of these mosquitoes about, 
 yellow fever can not spread. The danger in Texas is that the steg- 
 omyia mosquitoes, that have bitten people with yellow fever, will live 
 through the winter and spread another epidemic as the warm weat her 
 comes on by biting people who have not had the disease. This mos- 
 quito, from its nature, stays immediately about the house and in the 
 rooms, and seldom or never wanders far. It was found in I labana 
 that by destroying all the mosquitoes in each house where yellow 
 fever occurred the disease was always stopped in that particular 
 neighborhood. It is probable, therefore, that if each householder in 
 whose house yellow fever has occurred during the past fall will 
 destroy all the mosquitoes in his house he will be free from the old 
 infection next spring. This can readily be done by closing the room 
 and making a smudge in it of sulphur or tobacco. Care should be 
 taken to paste all the cracks up with paper, so that the smudge will 
 be confined to the room fumigated, and the pan in which t ho smudge 
 is made placed on a little earth, so that it can not set the floor on fire. 
 
 With sulphur, about a pound to a room 10 feet square, should be 
 used, and with tobacco, about half a pound. To start the sulphur 
 burning a couple of tablespoonfuls of alcohol should be poured on 
 before applying the match. Sulphur should be used unless the room 
 
 
YELLOW FEVER. 249 
 
 contains valuable material which might be injured by it. The fumes 
 of tobacco hurt nothing, but leave a disagreeable odor. The fumes 
 of ordinary Persian insect powder hurt nothing and leave no odor, but 
 it does not always kill the mosquitoes and care has to be taken to 
 sweep them up afterwards. A couple of hours will be time enough to 
 keep the room closed. After that time it can be opened, aired, and 
 occupied. In towns, this method should be carefully carried out dur- 
 ing the winter by the town authorities. Not only the houses in which 
 yellow fever is known to have occurred, but every house in the infected 
 town should be treated in this way. We found in Habana that a squad 
 of five men, under intelligent direction, could easily fumigate a 10- 
 room house in two hours. It should be arranged so that the whole of 
 the infected town should be gone over before the 1st of April. 
 
 The above directions cover the points with regard to killing infected 
 mosquitoes, and thereby preventing the liability of a new epidemic 
 next summer from the old mosquitoes left over from last year. But 
 it is even more important to prevent the breeding of a new crop of 
 stegomyia mosquitoes, and this can be very readily done without very 
 great effort. 
 
 The female stegomyia mosquito always seeks some small body of 
 well-protected fresh water in which to lay her eggs. On the surface 
 of this water she lays about 60 or 70 eggs. These, in warm weather, 
 in three days hatch out into the ordinary wiggler, and the wiggler in 
 five or six days develops into the full-grown mosquito. From the 
 laying of the egg to the development of the full-grown mosquito takes 
 about eight days in hot weather. Water is as necessary to the insect 
 as it is to a fish. It is essentially a water insect during this period, 
 though it is an air-breathing insect, too, and has to come to the surface 
 of the water every few seconds to get air. 
 
 As I stated above, the stegomyia seeks particularly deposits of clean 
 water, and is essentially a house mosquito, breeding either in the 
 house or very close to it, in such places as cisterns and rain-water bar- 
 rels, and in anything likely to catch and retain rain water, such as old 
 bottles or cans, or gutters under the roofs of houses, etc. Now, if 
 every householder will give a little attention to see that there are no 
 such deposits about his house, he will be free from the stegomyia mos- 
 quito, and no one will contract yellow fever in his house, even if cases 
 are introduced into it from elsewhere. If necessity obliges him to 
 keep a cistern or barrels of rain water, if he will arrange the receptacle 
 so that the mosquito can not get in to lay her eggs, it will be entirely 
 safe. In the cistern this can be done by covering the top tightly, with 
 the exception of a hole for ventilation, and one for the entrance of the 
 water, and these two holes should be covered with wire netting. The 
 netting should be not larger than 16 meshes to the inch. A larger 
 mesh than this will allow the smaller size of stegomyia to pass through. 
 
 Water barrels can be arranged in the same way, a tight-fitting top 
 put on, with a wire mesh over the hole for the entrance of the water, 
 and a cheap spigot put in the bottom for drawing off water. If he 
 finds wigglers in any of the vessels of water which he is obliged to 
 keep, he can know that his coyer is imperfect, and that the female 
 mosquito has gotten in there in some way to lay her eggs. Small 
 deposits about the yard and in the immediate neighborhood should be 
 swept out or drained away. A deposit of water in Texas would have 
 to stand at least 10 days to breed a mosquito. For this reason, if the 
 
250 YKLl.ou PEVRB, 
 
 householder is not able to arrange his water vessels as above sug- 
 gested he could avoid breeding steiromy in mosquitoes by having t hose 
 vessels emptied once a week. But if tlie method of emptying is used, 
 the larvte should be carefully washed out or the vessel K-i't to stand 
 empty for more than an hour. If this precaution is not taken, a con- 
 siderable number of the larvae will he left adherent to the bottom and 
 sides and will live if the vessel is at once Milled. Kerosene oil is 
 fatal to the larvae if two or three tablespoonfuls are spread over the 
 surface of the water. 
 
 As I said before, the larvae have to come to the surface every few 
 :ids to get air, and as they are unable to break through the 1ilm 
 of oil they die of suffocation, out the oil evaporates very rapidly and 
 should be renewed every week. Much the better method is cither to 
 get rid of the deposit of water or protect it in the above-mentioned 
 manner. Oil should only be relied upon in treating deposits in a 
 building or its immediate neighborhood which can not be man aired in 
 one of the above-mentioned methods. Privy pits which contain water 
 were the only places in Habana in which we habitually resorted to oil. 
 
 In towns these methods should be enforced by regular and syste- 
 matic inspections. In most towns there are ordinances against pigs 
 and pigsties. A hog is considerably larger than a mosquito wiggler, 
 but with a little care an inspector will soon learn to discover the wig- 
 gle rs almost as easily as the hogs. And the householder should be 
 taught that the wiggler causes a great deal more annoyance to himself 
 and his neighbors than the hog does, and is infinitely more dangerous 
 to health. And the ordinances should hold the householder as strictly 
 to account for breeding wigglers on his premises as for having a pigsty 
 with a litter of pigs. The larger deposits, a hundred yards or more 
 away from the house, such as small ponds and swampy places, while 
 breeding mosquitoes that cause a great deal of annoyance, will not 
 breed the stegomyia to an extent sufficient to be dangerous to the 
 house. They should be managed by the town authorities on the same 
 general principles to drain wherever possible.