MAX VON PETTENKOFER MAX voN PETTENKOFER HIS THEORY OF THE ETIOLOGY OF CHOLERA + TYPHOID FEVER & OTHER INTESTINAL DISEASES +» A REVIEW OF HIS ARGUMENTS AND EVIDENCE BY EDGAR ERSKINE HUME M.D., DR.P.H., LL.D., MAJOR, MEDICAL CORPS, U. S. ARMY WITH 8 FULL-PAGE PLATES PAUL B - HOEBER - IN¢ NEW YORK 7 MCMXXVIL . Ye save - Fo HY Eke PUBLIC “RRARY HEALTH LIBRARY CoryriGHT, 1927 By PAUL B. HOEBER, Inc. Reprinted, with additions and corrections from Annals of Medical History (Vol. VII, No. 4, December, 1925) Published September, 1927 Printed in the United States of America PREFACE T is not easy to evaluate Pettenkofer’s contribution to Hygiene even today, nearly three-quarters of a century after the announcement of his “ground water theory.” He is overlooked entirely in many works on the epidemiology of intestinal disease, though usually mentioned in notes on good water. His theory, in so far as it embraces the idea of a prerequisite ““ripen- ing” of the germ in the soil before it is cap- able of producing disease in a susceptible individual, has of course been abandoned. Yet to Pettenkofer must be given credit for having recognized for the first time that there was some factor in the causation of intestinal disease other than the specific germ plus the individual who had never had the disease. Koch and his followers were unable to account for the frequent observa- tion that of a group of persons not pre- vii] MAX VON PETTENKOFER viously ill of a malady and equally exposed to the infection, only a certain number con- tracted the disease, and could not offer any satisfactory objections to Pettenkofer’s arguments. “Carriers” were of course not suspected, nor was there any understanding of the possibility of protective immunity produced by a mild or otherwise unrecog- nized attack of the disease. In keeping with the practice of that time, much effort was wasted in attacking the findings and theories of the other “school,” and such polemics consumed time and energy that might well have been expended in more direct study of the problem itself. To Pettenkofer must be allowed the credit for having given to his native Munich a pure water supply, the first great city to have this blessing. Pettenkofer, a young and intelligent epidemiologist, the first of his kind as we now use the term, came to Munich at the middle of the nineteenth century and found it a hotbed of disease. The burghers who drank water often devel- oped typhoid fever and many died. The viii] MAX VON PETTENKOFER more sensible people brewed their beer and did without water. Unconsciously inhabi- tants of the localities most heavily infected with typhoid fever turned to some other drink than water. Pettenkofer, having gained the confidence of those in authority, recommended that the long-trusted wells be abandoned and pure water piped in from a mountain lake. The Bavarian capital was suddenly transformed from a disease-ridden city to one of the most healthful in Europe. The example was quickly followed and soon Vienna and other places had good water supplies. Pettenkofer taught the self-purification of running streams but insisted that a pure water was better than a purified water, and recommended accordingly. Thus while denying the so-called “drinking water theory” of the etiology of intestinal diseases, he believed that bad water was in itself harmful. He always said that he was more in favor of pure water than the drinking water theorists themselves, holding that foul water might serve as a medium for fix} MAX VON PETTENKOFER pathogenic microorganisms, in which they multiply. Pettenkofer noted that there was a correlation between the use of polluted water and typhoid fever, and the importance of this observation is not diminished by his idea of the supposedly necessary “ripening” of the germ in the soil. Even Pettenkofer’s experimentum crucis, the swallowing of the living cholera vibrio, has not been without good results in the world, albeit he has been sharply criticized for that step. It showed that in the growth of bacteria, as in the growth of plants, a mere planting does not necessarily result in growth. He recognized that fresh air also was essential to health, and his exhaustive researches in ventilation and the metabolism of respiration brought about a new concep- tion of proper living conditions, one which 1s now universally accepted and which has contributed much to the increased expect- ancy of life, especially in children. He believed in the value of open spaces, and called parks the “lungs of the city.” His A MAX VON PETTENKOFER investigations of the relation of atmosphere to clothing, habitations and soil must not be forgotten. He was a versatile man. A great chem- ist, like Pasteur, the importance of his researches in the field of preventive medi- cine and hygiene has overshadowed his chemical discoveries. The chemist still uses his bile salts reaction, his methods for the detection of arsenic and for the estimation of carbon dioxide in air and water, and builds on his studies of the sulphocyanates in the sputum, of hippuric acid, of creatine, creatinine, etc. He was a pioneer in the teaching of hygiene as a separate branch of medical science and was the father of the first Hygienic Institute, opened in Munich in 1879. He had at that time been a professor at the University of Munich for some twenty-five years, during twenty of which his department had been known as the Department of Hygiene. In the following pages will be found an account of Pettenkofer’s conclusions on the xi MAX VON PETTENKOFER subject of the cholera epidemic in London in 1854 and the rdle played by the notorious Broad Street pump. If we are inclined to criticize him for not recognizing with Snow that the epidemic was entirely water-borne, we may well remember that the royal Col- lege of Physicians, while admitting that there was much to justify Snow’s belief, held that the cholera poison was in reality carried from place to place by the wind. We have come to realize what possibly was overlooked for a time, namely that bacteriological study, while of the highest importance in the investigation of the causa- tion of disease, is not alone sufficient. Epi- demiological investigation must likewise be made, using many such methods as those employed by Pettenkofer. Those who give consideration to this latter science must accord Pettenkofer’s contributions an important place in the development of our knowledge of the natural history of disease. Epcar ErksiINE HUME. ARMY MEDICAL LIBRARY, WasningTon, D. C,, September, 1927. of xii CONTENTS PAGE PREFACE. «bile ol vo bi a wieder LisTOF ILLUSTRATIONS +. + « « « + + + +» +» +» XV 1. INTRODUCTION. = « 5. v. s'% & = = iol = 0s I IL BrograrHy |... . «i iow ee sa eH III. ETioLocy oF CHOLERA AND OTHER INTES- TINAL DISEASES . » ov 5 v ws » + » @5 IV. CONCLUSION. « vviilin «0 4% oa «wi. 107 B1BLIOGRAPHY OF PETTENKOFER’S WRITINGS . 109 xiii} LIST OF ILLUSTRATIONS PAGE Max von Pettenkofer Frontispiece Title Pages of Pettenkofer’s First Publication. Published While a Student, 1842. . . . . . 7, 11 Title Page of Pettenkofer’s Thesis for His Doc- ROTEL, YUBA wo vi ovis a sie EA wwe 14 Max von Pettenkofer. . . . . . . . . . .. 29 Title Page of Pettenkofer’s First Publication on the Etiology of Cholera, 1855 . . . . . . . 47 Pettenkofer’s Graph of Cholera Morbidity and Ground Water Level in Munich, 1873-1874. 83 Chart of Variation in Ground Water and Mor- tality from Typhoid Fever in Munich. . . . 93 xv] N undertaking a study } of Pettenkofer’s life and SY work, one is struck by os the facts that, first, ER there is no biography * : Ay other than the several EL yr SOL) obituaries and other < SL 2% brief sketches in various journals, and second, that as far as can be ascertained no complete bibliography of his * Since the completion of this study there has appeared an interesting series of sketches of Petten- kofer, considering him as a man, as a chemist, as a hygienist, as an epidemiologist, etc., by Dr. Otto Neustiitter, formerly director of the Historical- Ethnological Museum of Hygiene in Dresden. This little book forms one of Prof. Max Neuberger’s series of “Meister der Heilkunde.” See p. 29. Ii] MAX VON PETTENKOFER writings has been prepared. This is indeed unusual for such exist for so many German investigators whose influence has been far less-thait that of Pettenkofer. Of his writings, $1.0 hut, few: translations were published so that “Lin nearly "évery instance the article in the original German was consulted. While it was desired to ascertain Petten- kofer’s view of the epidemiology of cholera and similar diseases, it was found impossible to consider this phase of his work without also looking into his investigations of other kinds, since much of the work overlapped and a consideration of the entire scope of his activities was necessary in order to gain a proper and sufficiently broad conception of his life, work and beliefs. Thus only does one appreciate the important role he played in the moulding of popular opinion and in inspiring other scientific workers. The state- ments of Emmerich, Gruber and von Voit, Pettenkofer’s most eminent assistants and pupils, are taken as authoritative. Chapter 11 consists of a biographic sketch of Pettenkofer together with a brief con- I} MAX VON PETTENKOFER sideration of his researches along lines other than epidemiological. Chapter 111 consists of a consideration of his views as to epidemiol- ogy, particularly the epidemiology of cho- lera, typhoid fever and other diseases of the alimentary tract. There is appended a com- plete bibliography of Pettenkofer, collected from sources in the Army Medical Library, as well as articles elsewhere which bear on Pettenkofer’s opinions. References to these throughout the text are by number. I3F II BIOGRAPHY AX PETTENKOFER was born on December 13, 1818 at Lichteinheim near Neuburg on the Danube, in Bavaria. He was one of eight children, and his father, a small proprietor, had difficulty in providing for the large family. Therefore the uncle of the future scientist, Dr. Franz X. Pettenkofer, a chemist of note, took his nephew, then aged nine, into his home in Munich and directed his studies. Naturally the boy became interested in chemistry and thus from his earliest childhood he developed a taste for minute analysis and careful enquiry into the laws which govern the phenomena of nature. His uncle was court apothecary and young Pettenkofer was taken into the establishment as apprentice. He attended in turn the Volksschule, the Latin school and the Gymnasium, where he 4} MAX VON PETTENKOFER completed his course with distinction in 1837. In the same year he entered the Uni- versity of Munich with the intention of studying philology, but, probably owing to his connection with the court apothecary, his purpose was altered and he undertook the study of chemistry. He wrote verses, especially sonnets, a collection of which was published in 1886.2! All went well until a dis- pute with his uncle caused him suddenly to leave the latter’s house. Without resources, the youth of twenty years was unable to earn a livelihood as a chemist so that, partly for want of a better occupation and partly on account of a return of an old love for literature and art, he became an actor. He played several roles in Ratisbon, where the press commented most favorably on his histrionic ability. He might have continued this life had not his cousin, Helene Petten- kofer, whom he afterwards married, effected a reconciliation with his stern uncle. He then returned to his studies in Munich, now following the courses in the Medical Fac- ulty, always with a strong leaning towards 4s] MAX VON PETTENKOFER chemistry. The celebrated mineralogist, Johann Nepomuk von Fuchs, recognized his ability and it is probably due to von Fuchs’ influence that Pettenkofer accomplished so much in chemistry at such an early age. Indeed, had it not been for his uncle, who planned a career of court apothecary for his nephew and who therefore insisted on his completing his medical course, Pettenkofer would certainly have given all his time to chemistry, and might never have graduated in medicine. While still a student, Pettenkofer pub- lished two researches. The first of these! was a valuable method, still used in forensic medicine, for the demonstration of the presence of arsenic by means of the Marsch apparatus. The second article was on the separation of arsenic from antimony, also by means of the Marsch apparatus.? In 1843 Pettenkofer completed his uni- versity studies and received the degree of Doctor of Medicine and Surgery. His grad- uating thesis* was on the South American plant Mikania Guaco. 46] SUSAN AANA AT ATA A STATA AT ATA ATA 44 AA - SNL SE SRR NL BL IN Fe Te Hew v - ; N= 78. SN NN ae [Ee Repertorium “ fur die 1 Pharmacie l[g — Herausgegeben zu Miinchen : : Dr Buchner. © Zweite Reihe. Band XXVI. Heft 3. HI £24 AAR &* I " . eq ; } *otid Ta EE } 4 : 5 Niirnberg, 1842. Bei Johann Leonhard Schrag. & SN AAA IAIN A fs AENEAN NE TitLE PAGE OF PETTENKOFER’S First PuBLICATION. PusrLisnep WHILE A STUDENT, 1842. {7 MAX VON PETTENKOFER The preference for the study of chemistry which had characterized his university course now became even more marked, but he directed his attention more particularly to chemistry in its medical aspects.’ He had neither inclination nor talent for the practice of medicine. Nevertheless his medi- cal studies stood him in good stead later in his epidemiological work. At this time there was no institute In Munich where chemical and physical research could be carried out. In this respect Munich was somewhat behind the other German universities. Chemical study cen- tered in the University of Giessen, where Liebig drew to his laboratory all who aspired to prosecute chemical research. There was no vacancy with Liebig just then, so that upon the advice of Fuchs, Pettenkofer went to Wiirzburg to work with Josef Scherer, who was among the first to recognize the value of connecting chemistry and physiology and was in a way one of the founders of what is now physio- logical chemistry. {ol MAX VON PETTENKOFER Pettenkofer carried out several pieces of chemical research in Wiirzburg. One of the first was the demonstration of hippuric acid® in the urine and of its relation to food. The most important of these researches was the discovery of the principle named after him, Pettenkofer’s test for bile,” a discovery which has been, and still is, of the greatest Importance to the chemist, the physiologist and the physician. This discovery, Voit tells us, was not the result of chance as is so often stated, but came of clear logic and careful observation (Voit, #4 p- 13). Prior to this test there were no means of recognizing the presence of the bile salts, but by Pettenkofer’s well-known test even the minutest quantities are demonstrable. Of almost equal importance was his discovery of a new nitrogenous product in the urine. This research was begun in Wiirzburg but finished in Giessen in the summer of 1844. The substance was clearly demonstrated and described and Petten- kofer made an elementary analysis of it. fro} Second TITLE PAGE or PETTENKOIER’S FirsT PUBLICATION. PusLisnED WHILE A STUDENT. : 1 1 MAX VON PETTENKOFER Yet Liebig in his great work on the consti- tution of urine (1843),%%" takes no notice of 1t although it had caused no little com- ment. However in 1847, when Liebig pub- lished his “Chemical Study of Meat’ 258 he showed that the substance was a com- bination of creatine and creatinine. Thus was shown for the first time the fate of the creatine of the muscles. In the summer of 1844, Pettenkofer was finally able to go to Giessen to work under the guidance of the renowned Liebig.!*! During this time, he acquired the viewpoint to which he adhered ever afterwards. Liebig was a wonderful teacher who, Pettenkofer said, instead of the aphorism of Mephisto: “Das Beste, was du wissen kannst, darfst du den Buben doch nicht sagen,” insisted that “Alles was ich machen kann, das miis- sen auch die Buben machen lernen.” (Voit, p- 15.) Gladly would Pettenkofer have remained longer in such happy surroundings but lack of ready funds made it necessary for him to return to Munich. No professorship 13] Ueber Mikania Guaco. Inaugural- Abhandlung von Max Pettenkofer, Doktor der Medicin, Chirurgie und Gehurtshilfe, und appro. birtem Apotheker, Miinchen, 1844. Druck der Dr, C. Wolfschen Buchdruckerei. TitLE PAGE oF PETTENKOFER’s THESIS FOR His DocTorA TE 4 I 4 MAX VON PETTENKOFER being open, thanks to ministerial opposi- tion, he performed the chemical analysis for the hospital without pay for six months. Finally being forced to undertake some sort of remunerative work, he obtained by accident, in 1845, the position of assistant in the royal mint, at a salary of 114 gulden (60 cents) per day. He took much interest in this work at the mint’ where his natural talent for research showed itself to advantage and enabled him to introduce an improvement in the method of assaying silver and gold. He found that the Brabant or Crown Thaler always contained a large percentage of platinum? and that this mixture thereto- fore unsuspected was the chief cause of many difficulties with which the refiner had to contend. His work not only improved the coins” but resulted in a saving of valuable metals.!? While employed in the mint Pettenkofer carried on a certain amount of research not connected with his official work. He proved definitely that the saliva contains 15] MAX VON PETTENKOFER sulphocyanic acid.® This had been stated by some, but others insisted that the compound, which reacted like sulphocyanic acid, was really acetic acid which with ferric chloride gives the same red color. Pettenkofer made a quantitative estimation of the sulphocyanic acid. Another bit of research at this time was the demonstration of a new substance in the urine, which is now known as oxyproteic acid. A third noteworthy study made during this period was upon haematinon.*® This substance was used in the manufacture of the antique red glass known to the ancients as porporino. King Ludwig 1 was most desirous of having the substance reproduced and sent a commission to Pompeii tostudy it. Pettenkofer succeeded in reproducing it where others had failed. This success was of the greatest importance to Pettenkofer in that it brought him to the attention of the kings of Bavaria, Ludwig 1 and his successor Max 11. Up to this time Pettenkofer had been unable to obtain a professorship on account ol 1 6] MAX VON PETTENKOFER of the continued opposition of the ministry under Abel, and indeed opposing views and the conflicting interests of individuals had seemed to thwart Pettenkofer’s every plan. But with the downfall of the Abel cabinet in 1847, conditions changed. A professorship of medical chemistry was created at the University of Munich and Pettenkofer called to fill it. He accepted the honor and on November 27, 1847 became professor at a salary of 700 gulden ($280) in money and two measures of wheat and seven meas- ures of rye, per annum. He was expected to carry on pathological-chemical investi- gation for the clinics and was allotted three rooms in the University building in Ludwigsstrasse. His first student was Carl von Voit who was associated with him later in so many researches on the physiology and chemistry of respiration, metabolism, etc. (vide infra). His lectures were not, like Scherer’s lectures in Wiirzburg, along the lines of medical chemistry, but more like those of Liebig on organic chemistry in its relation to physiol 17] MAX VON PETTENKOFER ogy and pathology. He changed the title of these lectures almost every year and it is interesting to note these changes as throw- ing light on his interests and views in the field of public health. The titles of the course were successively : Lectures on Dietetic-Physical Chemistry. Lectures on the Physical-Chemical Basis of Diet and Public Health. Lectures on the Physical-Chemical Basis of Diet as a part of Sanitary Regulations (Medi- zinische Polizei). Lectures on Sanitary Regulations. Lectures on Sanitary Regulations with Respect to the Physical and Chemical Foundation for the Study of Health. Lectures on Public Health with Respect to Sanitary Regulations. Lectures on Public Health for Physicians, Architects and Engineers. Lectures on Public Health and Sanitary Regula- tions. Lectures on Hygiene. The last title was adopted for the summer semester of 1865 and retained thereafter. 1 8 MAX VON PETTENKOFER Only once more did Pettenkofer turn his attention to pure chemical investigation. This was in 1846. The results of the work were published in 1850 in an article entitled “Ueber die regelmissigen Abstinde der Aequivalentzahlen der sogenannten ein- fachen Radikale.”?' This work was pre- sented at a session of the Academy. In 1849, the architect Leo von Klenze called Pettenkofer’s attention to the super- iority of English (Portland) cement over the German product, in that it would set much more quickly. Pettenkofer accord- ingly set about ascertaining the cause of this difference and attempted to provide a satisfactory German cement. The task was at first entrusted to Hopfgarten, one of Pettenkofer’s students'®* who, assisted by Pettenkofer himself, finally perfected the new process and produced a German cement of good quality.® It was at this time that Pettenkofer began his experiments on the manufacture of illuminating gas from wood.* This had been many times attempted but without success fio} MAX VON PETTENKOFER as wood gas could not compete in illumina- tion value with coal gas. Pettenkofer’s efforts to devise a suitable wood gas process were finally successful and he contracted to light the city of Basel. This wood gas proc- ess was used for many years in various parts of Europe. It was only given up when the decreasing supply of wood made its cost prohibitive. 23178 In the preparation of pyroxalic acid (Holzess1g) in connection with the manu- facture of wood gas, Pettenkofer isolated a by-product which he at first took to be pyrogallic acid but later (1854) found to be pyrotannic acid (Brenzkatechussdure). A study of this substance was made the sub- ject of a paper (Voit,”* p. 34). Thus Pettenkofer, at the age of thirty- three, had a wide reputation as a research chemist, his work on platinum, haematinon, cement and wood gas being known every- where. Pettenkofer began his first research in the field of hygiene in 1851. This was a study of the differences in methods of heating build- q 20] MAX VON PETTENKOFER ings by hot air and by means of stoves (fur- naces) with regard to the air of the spaces heated.?? This, like certain earlier work, was undertaken at the request of King Max 11. While engaged on this work Pettenkofer demonstrated for the first time the permea- bility of the walls of our dwellings to air, a fact now universally recognized. At about this time, Pettenkofer com- pleted several minor pieces of research, the most important of which was probably the preparation of a copper amalgam for use as a dental filling material.’® In 1851 he made an exact analysis of the water of the Adel- heid Spring at Heilbronn in Upper Bavaria. 2 In 1850 Pettenkofer’s uncle died and shortly thereafter King Max 11 appointed Pettenkofer court apothecary. This posi- tion brought with it an increase in his income and gave him as a residence the house in which he had been brought up. King Max, who was ever desirous of bringing to the University of Munich as many savants as possible, appealed to Pettenkofer to use his good offices to induce Liebig to Jar} MAX VON PETTENKOFER accept a call to Munich. Liebig had stead- fastly declined to leave Giessen but when the matter was urged on him by his former pupil, the celebrated old professor con- sented. Pettenkofer described his connec- tion with the event in “Wie Justus von Lie- big nach Miinchen kam.” In 1853 Pettenkofer was made ordinary professor of medical chemistry on the Medi- cal Faculty. In the new Physiological Institute, founded in 1854, Pettenkofer was given a suite of four rooms, where he worked with von Siebold, Bischoff, Harless and von Voit. The first work in this new laboratory was on the zinc content of the air’ and the question of how deep a layer of zinc was necessary to prevent oxidation. This work has been of considerable value in preserving the wires used in telegraph lines. Pettenkofer now continued his work on the study of the air in dwellings, which he had begun in 1854.* He took as an indicator the time required for the carbon dioxide of a room to increase or decrease. 22] MAX VON PETTENKOFER For this purpose he devised his well-known method*? for carbon dioxide determination. He went to Paris to continue his investi- gations. In 18548, he announced his ideas regarding the natural air change in buildings —the basis of artificial ventilation. 4 This was a mighty exposition, full of new ideas and setting forth principles which are still accepted. In the period 1857-1865, Pettenkofer and his pupils also studied the value and effect of clothing.73122 His observations as a member of the Cholera Commission, of the relationship of the soil to the cholera epidemic of 1854 (cf. also p. 83) caused Pettenkofer to consider the relationship between the soil and air.'?? He noted that the air does not stop at the ground line, but that the soil is itself a mix- ture of earth, air and water. By adding water to a volume of earth in a jar, he showed that it takes up over one-third of its volume of air. Pettenkofer’s well-known experiment to show the permeability of the soil to air was made by placing a canary {23} MAX VON PETTENKOFER bird in a jar between two layers of soil, the upper resting on a wire netting. The bird, requiring about 114 cubic inches of oxygen per hour, lived thus for several days, showing that the air passed through the stratum of soil. Observations of miners who have been imprisoned in shafts confirm this point. The air in the soil is affected by winds, temper- ature, etc., just as is the air above the ground level. Frozen earth is not comparable to normal soil, since it is no longer capable of taking up air because ice fills the interstices stead of water. In 1871, Pettenkofer continued his studies of the relation of the air to the soil. He first made estimations of the carbon-dioxide content of ground air, samples being with- drawn by lead pipes, and found that the carbon-dioxide layer in the soil varies in thickness.!'* It is, he said, derived from processes of decomposition of living organ- isms. If his hypothesis as to the origin of carbon dioxide were correct, there would be no more of it in a vegetationless soil than in the air above the surface of the 24} MAX VON PETTENKOFER ground.'?® To prove this he made a series of examinations of the carbon dioxide in the soil of the Libyan desert, being assisted by von Zittel in the work. They found, as Pettenkofer had expected, that the carbon dioxide in the soil was not greater in extent than in the air above. One of the two greatest pieces of research done by Pettenkofer, other than in the field of epidemiology, was his study of the physiology of respiration,*® metabolism, nu- trition and food values. In this work, which extended over more than twenty years, he was ably assisted by Carl von Voit. (Ref. 63, 64, 106, 132, 134, 169, 179.) The famous Respiration Chamber®? was constructed at a cost of over 700 gulden ($2800), the expense being defrayed by King Max 11.4%5%51 By means of this apparatus, meas- ured air was admitted to the individual within, while the exhaled air, feces, urine and so forth could be collected and examined. (Ref. 54, 55, 60, 63, 64, 68, 69, 72, 85, 92, 93, 132, 139.) These were the first studies of metabolism in health and disease. (Ref. 73, 25] MAX VON PETTENKOFER 84, 97, 105, 106.) Space will not permit here a full account of all phases of this research of Pettenkofer and von Voit, which was con- ducted by von Voit alone when Petten- kofer’s attention was claimed by his studies in epidemiology. Pettenkofer assisted in the reestablish- ment of the use of meat extract. This had long been known and had been first used for wounded patients as early as 1821. Liebig had devised a process for its manu- facture in South America from beef. Petten- kofer persuaded his uncle to carry it in the court pharmacy and list it in the Bavarian pharmacopeia. When Liebig came to Munich, the name “Liebig’s Meat Extract” was officially adopted. In 1862, the plant for its production opened at Fray Bentos in South America and from this the Liebig Fleisch Extract Compagnie developed. Within a comparatively brief time by applying the method of Liebig and Pettenkofer 1500 cattle were used daily. In 1863, at the instance of Friedrich Pecht, Pettenkofer worked out a method 426] MAX VON PETTENKOFER of restoring oil paintings. The increasing damage to paintings in the galleries of Munich had become alarming, so that Pettenkofer was appointed one of a commis- sion to study the cause and suggest a remedy. In this he was successful. This single piece of work, von Voit (Ref. 274, p. 64) observes, would have been sufficient alone to have won him world fame. The trouble lay in the formation of a sort of mildew or mould (Schimmel) on the paint- ings. This caused the varnish to become opaque, thus giving the paintings a cloudy, blurred appearance. Pettenkofer made a chemical investigation of the oils, pig- ments and so forth and found that the fault lay with the oil in which the pigments were dissolved. It underwent a change in the course of time due to the taking up of oxygen from the air which resulted in a hardening and loss of translucence. This came about by a condensation of water vapor on the surface, while a resulting molecular change in the varnish brought about cracking of the surface. Pettenkofer 27} MAX VON PETTENKOFER observed that these defects occurred only in damp museums and galleries. He pro- duced the changes experimentally. The remedy was also suggested by him: by dint of application of hot alcohol vapor the cracked varnish fragments were united, rendered translucent and the painting made clear again. Naturally to prevent the forma- tion of this mildewing it is only necessary to prevent the precipitation of water on the painting as Pettenkofer showed. The Bav- arian government appropriated 40,000 gul- den to carry out the restoration of the paintings already damaged. From this time forth, Pettenkofer’s atten- tion was occupied chiefly by the study of the epidemiology of cholera and other intes- tinal diseases, but nevertheless he found time for a certain amount of other study and research. A good part of this was on the subject of respiration and, as before, was done in collaboration with von Voit. Pettenkofer realized the value of educat- ing the general public on the subject of public health as a hygienic measure. He a8} Max voN PETTENKOFER (1818-1901). J29]¢ apd Reali YEN i 0 WERT XE by be tie The i Img Behe SE a AL ay : po \; t | AJ o ph. MAX VON PETTENKOFER was much in favor of popular lectures for this purpose and gave many in Munich and elsewhere.'® At that time, many of the leaders of scientific thought felt it beneath them to lecture to others than students of science. In a lecture delivered in 1873 before the Verein fiir Volksbildung in Munich on the value of health to the city, he begins: “Everyone who lives upon the earth desires to be well, for a life without health is a misery—a martyrdom from which everyone longs for release, and when it may not be by other means, even by death.””!*? He called the attention of the city of Munich to the financial saving resulting from improved health of the people, due to sanitary reforms, in which he had himself taken such an active part. The money value of the working time lost he estimated at 3,400,000 gulden annually for the city of Munich (population then 170,000). Petten- kofer added that if Munich would bring its sanitation up to the standard of London, where the death rate of 42 per 1000 which had prevailed since 1681, fell to 22 per 1000 q3 1 I MAX VON PETTENKOFER in 1856, 25,000,000 gulden would be saved each year.’® (Voit,#*p. 127.) He said that it was worth the munici- pality’s while to install sewer connections at public expense for those who were unable to pay for them. Sanitation, says Emmerich, had come to be regarded as consisting of good sewerage, satisfactory toilets and a proper water sup- ply. Pettenkofer recognized the value of all these but stated that the public health depends on a combination of all factors which in any way influence man. Among other factors he mentioned food and air, the preservation of body warmth and good living conditions, such as ventilation. He pointed to England, where drafts are less feared than in Germany, and said that their better health is partly due to penchant for fresh air. Dirt (Schmutz) he says must not be tolerated. He was inclined to agree with Lord Palmerston in defining dirt as “every- thing which is not found in its proper place.” (Voit,?* p. 128.) 32} MAX VON PETTENKOFER Pettenkofer deplored the extensive Ger- man abuse of alcoholic drinks, claiming that the deleterious effects manifest them- selves in the entire people.’*® He was in favor of temperance if not actual prohibi- tion. The Miinchner Verein gegen Miss- brauch Alkoholischer Getrinke received much assistance from him. In 189g they erected, in his honor, the Pettenkofer Fountain in the building of the Academy of Medicine. Just as condiments make food taste bet- ter, so Pettenkofer said that anything in nature that makes life more pleasant is valuable. In 1877, he wrote “Ueber den hygienischen Werth von Pflanzen und Pflan- zungen im Zimmer und im Freien.” Herein he endeavored to answer those who said that plants and the like were useless to the city. He admitted that the old idea of plants purifying the air and acting as the “lungs of the city” was groundless but yet said that they are of value since they tend to purify the soil, to offer shade, which is of real hygienic worth, and not least, in that 433] MAX VON PETTENKOFER they are of esthetic value and beautify their surroundings, something not unimportant from the hygienic standpoint. Pettenkofer always believed that hygiene should be an independent department in the university and urged this again and again. Opinion was not in his favor at first, but he won over more and more of the faculty, although he could never get a majority of the Academic Senate. However, im 1864-1865 when Pettenkofer was rector of the University of Munich, the youthful King Ludwig 11 in an audience with him asked if he had no personal request to make. Pettenkofer replied with a request that hygiene be made a full chair in all the Bavarian universities. The king at once summoned the minister of education and a conference was held. The result was that, in 1865, an order was issued that hygiene was to be a full subject and required in the medical examinations at the three Bavarian universities (Voit,”* p. 132). Pettenkofer was accordingly made the first professor of hygiene at Munich. At the same time 34 MAX VON PETTENKOFER Scherer and Gorup-Besanez were given the chairs at Wiirzburg and Erlangen respec- tively. It is interesting to note that all three were, like Pasteur, chemists. There were at first many difficulties in the path of the study of hygiene. Its scope was too restricted and some wanted it taught as an appendage to other studies, e. g., state medicine. Prior to Pettenkofer, hygiene was merely a collection of empirical statements, would-be truths, and mere opinions as to what was harmful to man. There was no possible relation between such ideas and Pettenkofer’s own conception of hygiene. In order to set forth his views, he presented a carefully worked out series of lectures, the titles of which are of interest in this connection because they constituted the first regular course in hygiene. They were: 1. The Atmosphere and its Constituents. 2. Physical and Chemical Changes in the Atmosphere; Atmospheric Climate. 3. Clothing and Care of the Skin; Care of the Body; Exercise. 35} MAX VON PETTENKOFER 4. The Retention by Building Materials, of Air, Water and Heat. 5. Ventilation. 6. Heating. 7. Lighting. 8. Building Sites and Building Grounds. 9. Ground Air and Ground Water. 10. Influence of Soil Conditions on the Occurrence and Spread of True Diseases as well as Means of Protection against Them; Local Climate. 11. Drinking Water and the Care of Human Habitations. 12. Food and Its Relationships. 13. Milk, Meat, Bread, Vegetables, Fruits and Other Plant Foods. Alcoholic Drinks, Vinegar. 14. Nutrition and Care of Various Classes of Society under Varied Conditions. 15. Collection and Disposal of Feces and Other Refuse of the Home and Factory; Sewerage. 16. Disinfection. 17. The Coroner and Burial Regulations. 36] MAX VON PETTENKOFER 18. Health in Dangerous Trades and Factories. 19. Schools, Barracks, Nursing Institu- tions, Hospitals, Prisons. - 20. Poisons and Regulations for the Care and Handling of the Same. 21. Medical Statistics and Biostatistics. As there were at that time no textbooks or journals of hygiene, Pettenkofer pub- lished his articles in such periodicals as Dingler’s Polytechnisches Journal, Abband- lungen der Naturwissenschaftlich-technischen Kommission, Kunst-und Gewerbeblatt, Sit- zungsberichte or Gelebrte Anzeiger der Aka- demie, Aerztliches Intelligenzblatt, etc. The journals of pure chemistry or physics had no space for such material. Therefore his first work in hygiene was little known. In 1865 Pettenkofer and Voit founded the Zeitschrift fiir Biologie in which his labors for the next eighteen years were collected. With the further development of hygiene as a subject in all the German universities, a journal for this specialty was needed. q3 7k MAX VON PETTENKOFER Pettenkofer and some of his pupils founded the Archw der Hygiene, the first periodical in the world devoted entirely to this subject. After the appointment of the professors of hygiene in the Bavarian universities, those in the other German institutions fol- lowed, the first being Meissner at Gottin- gen. In 1883, hygiene was required for all examinations in the German empire. There was at first no laboratory for students of hygiene in Munich, and they were accommodated in a small part of the Physiological Institute. In 1872, Petten- kofer received a call to the University of Vienna and consented to remain in Munich only on condition that they would build a Hygienic Institute similar to the one offered him at Vienna. This the Bavarian govern- ment consented to do. The Hygienic Institute was opened in 1879, being the first hygienic laboratory and serving as a model for many later ones. It must not be forgotten, however, that in Great Britain prior to this time military surgeons had received instruction in hygiene 138) MAX VON PETTENKOFER and a laboratory under Parkes was in use. It was, of course, much less extensive than the Hygienic Institute of Munich. Students from all countries now came to Munich to study hygiene with Pettenkofer, just as in his youth all those desiring instruc- tion in chemistry had gone to Liebig in Giessen. In 1876, Pettenkofer was offered the appointment as head of the newly created German Empire Health Council. This rec- ognition of his standing was deeply appre- ciated by Pettenkofer but he declined the office because he thought he could render more Important service in teaching. He became a scientific adviser to the Council, however. Pettenkofer always strove to improve the general health conditions in Munich, but for a long time received but little support. Finally he was able to interest the burgo- master, Alois von Erhardt, and the city architect, Arnold von Zenetti. Clean water was brought in sufficient quantity into the city from the mountains and furnished to 430} MAX VON PETTENKOFER all houses. The Central Abbatoir was estab- lished in 1878. The disposal of excreta was the hardest problem.%%22° In the same year, Pettenkofer and his pupil Emmerich showed that the water from the Isar remained good even though there were sewer pipes in the ground. This had been doubted. It was also shown that the sewage could be discharged into the swift Isar'®* without danger since the dilution was so great.?'? (Voit, 24 p. 143.) With these steps the great cleaning up of Munich began. The result was that the general mortality of 40 per 1000 of 1870 fell to 30 per 1000 in 1890 and the mortality from typhoid fever from 72 per 100,000 in 1880 to 14 in 1898. Munich became and has remained one of the healthiest of cities. Not only was the sanitation improved but better buildings were constructed. Munici- pal pride was aroused and Pettenkofer became the most beloved citizen of Munich. In 1872 he was made Ebrenbiirger and in 1893 on the fiftieth anniversary of his doctorate he received the Gold Burgess Medal, the highest honor in the gift of the 40] MAX VON PETTENKOFER city. It was inscribed: “Als Beweis der unendlichen Liebe und Verehrung der Miin- chner Biirgerschaft fiir ihren Fiihrer auf dem Wege des gesundlichen Fortschritts.” On his eighty-first birthday he received a golden medallion bearing his profile and inscribed: “Dem Hohenpriester der Hygiene, dem Verscheucher Verderben bringender Krankheiten vom heimathlichen Boden, dem um das Wohl der Vaterstadt hichst verdienten Max von Pettenkofer widmen diese goldene Denkmiinze als Zeichen unbe- grenzter Verehrung, Dankbarkeit und Liebe Miinchner Biirger.” Findlingstrasse, in which he had done his work and where the Hygienic Institute is situated, received his name after his death and a large monu- ment to him was erected there. On the fiftieth anniversary of his doctor- ate, Burgomaster von Borscht said: The fountain which sprang from five decades of activity from the depth of scientific foundation did not have its fruitful force limited in its immediate surroundings; it has grown to a mighty stream and has flowed over {ub MAX VON PETTENKOFER the whole Fatherland and out over the entire civilized world. There is no progressive city today that has not made an effort to apply Pettenkofer’s teachings and there is no civilized country that has not given public health, in Pettenkofer’s sense, an important place in its life. Pettenkofer’s merits were recognized by governments and learned societies every- where. He was given personal nobility, then hereditary nobility and in 1896 the title “Excellency.” In 1897 he received the gold Harben Medal of the British Institute of Public Health—notable as he himself said, as coming from the land which led in public hygiene. In 1899 he received the medal of the German Chemical Society for his work on atomic weights. On his seventieth birth- day, his pupils presented a marble bust of Pettenkofer by von Riimanns (now in the Hygienic Institute), and the city of Munich gave 10,000 marks as a Pettenkofer Foun- dation for Hygienic Investigation, while Leipzig contributed 5,000 marks for the same purpose. 42] MAX VON PETTENKOFER In 1890, on the death of Déllinger, Pettenkofer was elected president of the Academy. In 1894 he began to retire from all work. He gave up teaching in that year and two years later resigned as court apothecary. He resigned as president of the Academy in 1899. He continued to live in winter in Munich and in summer on the Starnberger See. Even at the age of eighty- two, he would row his boat about the lake and take long walks in the forests. But he began to feel that he could no longer think as before and was of no more use to the world and was tired of life and wanted to die. All his family, his wife, two sons and a daughter had predeceased him. In January, 1901 he had a severe infection of the throat which caused him much pain and a pronounced melancholia made its appearance. (At autopsy advanced chronic meningitis with considerable calcification was found.) In 1889 he had written about Soyka of Prague, his former pupil, who killed himself in an attack of melancholia. “Suicide is 43] MAX VON PETTENKOFER no heroic death, and only to be condoned when it is for the benefit of loved ones or when done by one irresponsible. In such a case it is a tragedy.” (Voit,”* p. 160.) He ended his life just after midnight on February 10, 1901 by a revolver shot. (Gruber, ?#® p. 7.) Jaa] ITI ETIOLOGY OF CHOLERA AND OTHER INTESTINAL DISEASES PETTENKOFER’S THEORY RIEFLY stated Pettenkofer’s Boden theory of cholera is as follows: In order for an epidemic to occur four conditions are essential: (1) a spe- cific germ; (2) certain local conditions; (3) certain seasonal conditions; (4) certain indi- vidual conditions. A specific germ exists but it alone can- not cause the disease so that there can be no direct contagion from person to person. Though individual susceptibility is an im- portant factor, this and the specific germ alone cannot produce the disease. Certain places enjoy a complete immunity from cholera and there are also certain periods of immunity. Without a consideration of 45F MAX VON PETTENKOFER conditions of place and time, it is impossible to account for the development of epidemics and the immunity of places. These seasonal and local variations are intimately con- nected with the germ itself and do not con- tribute to the causation of cholera by an mfluence on individual disposition. The “Infecting matter” is not a product of the intestines but of the soil. Thus we must dif- ferentiate between the “infecting matter” and the cholera germ. The cholera germ stands in the same relation to the “infecting matter’ as the seed does to the fully devel- oped plant. It is possible, if not probable, that the germ 1s capable of various degrees of development resulting in various degrees of infection. Pettenkofer’s investigations were con- cerned chiefly with the second and third of the above conditions. The immunity of certain places at all times and a seasonal or temporary immunity of other places is explained by the condition of the soil. A porous soil is necessary for the development of the cholera germ and in it there must be 46 Bur rage iiber pic Berbreitungdart der Cholera, Ol €ntgegrungen und Erlduterungen wu feiner Schrift Neher die Werbreitungsart der Cholera” von Dr. Magy Pettenlofer, Profeffor der mediyinifGen Chemie an ber Univerfitst Minden, Sinden, 1855. itevavifdsavtiftifde Anfalt Der 3. §. Cotta'fdjen Hudhhandlung. TitLE PAGE OF PETTENKOFER’S FIRST PUBLICATION ON THE EtioLocy oF CHOLERA, 1855. 47] MAX VON PETTENKOFER a certain degree of moisture, a certain pro- portionate mixture of air and water. The level of the ground or subsoil water serves as an index of the water content of the soil (Pettenkofer did not hold that the ground water is itself a factor though he is some- times misquoted in this regard). In a very damp soil, the cholera germ cannot develop but when the ground water level is lowered, i.e., when some of the moisture of the soil drains out, the cholera germ develops and the epidemic results. On the other hand the cholera germ cannot develop in soil that is too dry. On a soil that is impervious to water there can be no epidemic at all because the germ cannot undergo develop- ment in the absence of the proper degree of moisture. Not only must the soil be of the proper degree of dampness, but it must be “foul,” 1.e., contain decaying organic mat- ter. In this the germ is “ripened.” It is this ripened germ which when taken into the human body causes cholera. 148] MAX VON PETTENKOFER Tue SpeciFic GERM When Pettenkofer began his study of the epidemiology of cholera in 1854 there were two main theories regarding the cause of the disease, their adherents being known respectively as contagionists and miasma- tists. The contagionists held that the infec- tious material or contagium is procreated in the body of the patient and given off and directly transferred from him to the well individual by the act of touching, as in smallpox. The miasmatists thought that the causative agent or miasma exists out- side of the body of the patient but onlyina definite locality, and that nothing has to pass from the sick to the well individual, as in “intermittent fever.” The adherents of each theory cited many examples to uphold their views and to disprove those of the other “school,” and for years there were many polemics. The contagionists said that traffic and commerce had an undeniable influence on the spread of the disease, but the miasmatists answered that, Jao] MAX VON PETTENKOFER in spite of active traffic and undoubted importation of the disease, there are certain places always spared or only attacked at certain times. Some unfortunately decided that the disease could come about in either way. Pettenkofer early gave his attention to the old question as to whether or not cholera and typhoid fever are contagious. Although it had long been generally thought that they were, the Bavarian Sanitary Regulations of 1836”% on the advice of Philipp von Walther, the clinician, contained this state- ment: “The contagiousness of cholera patients, even when one lives near and with them or when one touches them and nurses them, is not to be feared.” (Voit, #4 p. 76.) According to the contagionists, the intes- tinal canal of the patient is the chief seat of the disease and here the infectious material ~~ (Infectionsstoff), the poisonous germ, is reproduced and increased in amount in the diarrhea. Pettenkofer was at first inclined to agree with this view and even 50} MAX VON PETTENKOFER as late as 1865 he thought the most impor- tant prophylactic measure was the disinfec- tion of the stools.** In 1867, however, he concluded that the fresh stools contain no dangerous matter else the attendants would be overcome in all cases. It is well known, he said, that patients in traveling dispose of their excreta most carelessly and yet even under these circumstances epi- demics fail to develop in certain localities. He decided that the disease is neither contagious nor miasmatic; that the error lay in the confusion of the terms contagious and transmissible (verschelppbar). Cholera and typhoid fever are, he thought, transmis- sible but not contagious, in that they may be transmitted from one locality to another but not from one individual to another. He proposed the elimination of the old terms contagium and miasm and distin- guished the infectious material (Infections- stoff) as ““entogenic” or ectogenic” according as the infectious material passes directly from the sick to the well (entogenic) or the germ or its products develops in the 451] MAX VON PETTENKOFER surroundings of the infected person before passing into the economy (ectogenic).?° There were two theories as to the mode of spread of cholera. The ephodists thought that the specific micro-organism, the cause of cholera, is endemic in lower Bengal from whence it is carried through human inter- course into different localities. It does not thrive outside its endemic locality and the micro-organism must be introduced anew each time in order to cause an epidemic. The autochthonists believed that the endemic focus exists in India but that spread of the disease is in no way connected with human travel, being more dependent on conditions in the particular locality and the time. Thus the germ can develop in other places than India (i.e., is autochthonous) but being sub- ject to other conditions it causes epidemics with less regularity and with longer intervals. Pettenkofer, while in sympathy with the idea of the essential factors of time and place, rejected the theory of the autoch- thonists, because, he said, it can never be proved that a locality recently attacked 52] MAX VON PETTENKOFER with cholera has had no communication with a place where cholera exists, and fur- ther evidence tends to show that there is something adhering to persons coming from localities where cholera exists which is capable of spreading the disease in a new spot. Pettenkofer was therefore an ephodist, but so were the contagionists; he therefore called himself a Localist, in that he held that the cholera patients and their excretions are not infectious but that only the local condi- tions existing at the time are capable of generating an epidemic by favoring the growth of imported infectious matter. In 1869, Pettenkofer expressed the opin- ion that both cholera and typhoid fever were caused by specific micro-organisms! elaborated in the bodies of the patients and discharged in the evacuations. In his later consideration of the subject, he calls the germ “x” for want of a better name. This germ, he said, may be transmitted not merely by patients themselves but also by well individuals coming from cholera locali- ties. This observation of a condition now oq 5 3 I 2 MAX VON PETTENKOFER explained by the existence of carriers, including those immune from previous attacks, is noteworthy. In 1883, when Koch demonstrated his comma bacillus, Pettenkofer at once accepted his work and stated that Koch had been able to isolate the “x” of which he had written so much. However this, he said, did not solve the problem in any wise for the vibrio alone does not produce cholera and the conditions regarding its spread were known before Koch’s discovery. With this statement of Pettenkofer’s, there began the conflict between the views of the two men which lasted as long as they lived and was continued by their pupils as late as 1910, when Pettenkofer’s assistant, Emmerich, and others published a monograph of some 800 pages on Pettenkofer’s Bodenlebre der Cholera Indica.?® So certain was Pettenkofer of his ground that the vibrio cannot of itself cause cholera, that he resolved to perform what he termed the experimentum crucis on his own person, I. e., to swallow the comma bacillus. If this q 5 4 MAX VON PETTENKOFER bacillus were the only cause of cholera, he could not escape the disease. Even the bac- teriologists were willing to admit this and warned Pettenkofer that his experiment would prove fatal. The experiment was per- formed on October 7, 1892 when Petten- kofer was seventy-four years of age. He received a fresh agar culture from Professor Gaffky which had been isolated from the rice water stools of a patient dying of cholera in the epidemic then raging in Ham- burg. A transfer was made into bouillon and of this Pettenkofer swallowed 1 c.c. on an empty stomach, the acidity of which had been neutralized by sodium bicarbonate. At the time, Pettenkofer called attention to the fact that the number of bacilli swal- lowed was of course far greater than the number ordinarily taken into the body under normal conditions of exposure. No symp- toms resulted except a “light diarrhea with an enormous proliferation of the bacilli in the stools.” (Voit,** p. 121.) Whatever we may think of Pettenkofer’s reasoning in this regard we cannot help 455] MAX VON PETTENKOFER admiring his courage. He had the utmost confidence in his theories so that in his old age we find him ready to make such an experiment on himself. Concerning this he wrote (Voit,”* p. 121): Even if I had deceived myself and the experiment endangered my life, I would have looked Death quietly in the eye for mine would have been no foolish or cowardly suicide; I would have died in the service of science like a soldier on the field of honor. Health and life are, as I have so often said, very great earthly goods but not the highest for man. Man, if he will rise above the animals, must sacrifice both life and health for the higher ideals. There was naturally manifested the wid- est interest in Pettenkofer’s experiment and his pupil Emmerich repeated it upon him- self. It was also carried out by a number of other pupils of Pettenkofer, including Stricker, Metchnikoff, Ferran, and others. (Emmerich,?® p. 735.) In two cases, a severe ‘‘cholerine” resulted, but no deaths. Pettenkofer and his followers made light of 156] MAX VON PETTENKOFER the cases of cholerine which they said could not have been cholera for there is a mor- tality of at least 50 per cent in cholera and none of these cases died. It was generally admitted that Pettenkofer and his asso- ciates had escaped cholera but Kruse? and a few others thought that they might have had light or atypical cases. Koch and his pupils said that Pettenkofer and the others did not get cholera because they lacked the “personal disposition” to the disease, but von Voit replied that surely one of the number would have been “disposed” to the disease. It was also suggested that possibly the culture that Pettenkofer used consisted of avirulent bacilli, but Pettenkofer replied that it had been isolated but four days pre- viously from a fatal case in Hamburg and moreover the bacilli had increased enor- mously in the intestinal canals of both Pettenkofer and Emmerich. There was no idea expressed of any acquired immunity or “lack of disposition” to the disease by rea- son of unsuspected infections by the cholera bacillus in the past on the part of any of Isr} MAX VON PETTENKOFER those who made the experiment on themselves. Pettenkofer’s experiment brought out one fact of importance for the first time. This was that the ingestion of the vibrio does not necessarily result in cholera. The possibility of immunity gained by an early unrecognized attack was of course not rec- ognized, but it showed that the implantation of the bacilli, like the planting of seeds, does not insure a growth. Locar CoNbpITIONS At the very outset of his work on cholera, Pettenkofer became interested in the impor- tance of local conditions. While a member of the Cholera Commission in 1854 he pre- pared a spot map of cholera incidence in Bavaria, using the general staff map. He indicated in red the places in which the dis- ease had appeared in epidemic form; in green those with sporadic cases; and in blue the places in which cholera was present in only one or two houses. This map was 58] MAX VON PETTENKOFER not published but is preserved at the Hygienic Institute of Munich. For Munich he prepared a “Record Book” from the official death certificates (almost 2000) showing the street, house and story in which each patient had lived. He desired thus to record the epidemic in such a way that it might be studied later from other viewpoints if desirable. He concluded from his study of the map that: (1) The disease was characterized by existence in certain localities with borders often sharply defined; (2) The spread was not by preference via channels of travel and commerce, 1.e., country roads and railways; (3) If in a valley there was a similar condition of the soil from the source to the mouth of the river, locali- ties on the upper part of the stream had been as a rule free from the epidemic which only appeared a long way from the source; (4) Places actually on the water shed usually escaped, the epidemic being limited to the river plains; (5) Moist and low lying places were in general more often and more severely attacked, than dry or highly situated ones. 450f MAX VON PETTENKOFER Having noted that the epidemic had been more or less confined to the neighborhood of the streams and rivers, he naturally studied the nature of the localities where the epidemic prevailed, and was soon con- vinced that certain conditions of soil, poros- ity, moisture and organic pollution, were essential for a widespread occurrence of the disease. This was the beginning of his theory regarding the importance of the condition of the soil (Bodenbeschaffenbeit) in the occurrence of cholera. The condition of the soil necessary for the development of the epidemic of cholera depends not on its geological formation, but on its physical condition. A “fouled” soil is essential. This 1s one which is porous in character, the interstices of which are filled in part at least with organic matter capable of undergoing decomposition in the pres- ence of the proper degree of moisture. Where no process of decomposition is found, Le, on a stony or compact (Impervious) soil there can be no local epidemic of cholera. The idea was not altogether new, for Jame- 460 MAX VON PETTENKOFER son in describing the cholera epidemics of 1817 and 1819 in India said: “Cholera does not appear to like a rocky soil.” ?%! Here again we have an example of Petten- kofer’s courage in that he staked his scien- tific reputation, which was very great, on this point and asserted that nowhere in the whole world could a place be found where a cholera epidemic had occurred where the houses are built on solid rock or other material impervious to water. As an example he cited the city of Nuremberg, where, not- withstanding considerable traffic between the several parts of the city, there were five times as many fatal cases of cholera in the sandy Lorenzer side of the city as in the stony Sebalder side.?*® This relation between the soil and the outbreak of the disease applies not only to localities but even to different houses in the same locality. Pettenkofer’s theory found many oppo- nents and these attempted to answer his arguments by citing instances in which cholera had occurred in places situated on 46 I I MAX VON PETTENKOFER rocky or other impervious soil. It does not appear to have occurred to them to ques- tion the existence of any absolutely imper- vious soil. Probably any locality if carefully examined would be found to fit Pettenkofer’s requirements as to the nature of the soil so that whether an epidemic occurs depends on whether or not its infection be introduced. Professor Drasche of Vienna?®® wrote in 1860 that he had found a place where an outbreak had occurred despite its situation on rocky soil. This was Krain in the Karst Mountains in Croatia. Pettenkofer did not attempt to reply but went immediately to investigate for himself. He speaks in the highest terms of Drasche whom he saw in Vienna on the way to Croatia. Drasche had never been to Krain but had based his article on geological maps. Pettenkofer made a study of the soil in six villages near Krain, listing the houses in which cholera had occurred. He found that a large group high up on a steep rocky hill had had no cases although filthy and occupied by the poorest people. On the 46 2] MAX VON PETTENKOFER other hand wherever there had been cases of cholera, Pettenkofer found a high-grade porosity of the soil or a splitting of the sub- soil so that the interstices were filled with organic material and retained moisture.5? Gibraltar and Malta were also mentioned as exceptions to Pettenkofer’s rule for, although on rocky soil, they had been visited by severe cholera epidemics. In 1868, Pettenkofer visited both places. In Gibral- tar he found a porous condition of the alluvial soil. The terrain in the upper part of the city was, as in the Karst Mountains, full of clefts and fissures in the rocks. More than two hundred wells were in use and he learned that, just prior to the epidemic of 1865, there had been a marked rise in the ground water level followed by an abrupt decline.’**!1® Malta he found to be a stony island but the crystalline sand- stone surface was soft and porous. Twenty- eight per cent of the stone consisted of pores. It was so soft that it could be cut with a knife. Thus Malta instead of being a compact rock was a sort of stony swamp 46 3f MAX VON PETTENKOFER containing a large amount of moist decom- posing material!!! Similarly when, in 1885, Koch stated that the surface of Bombay and Genoa, where epidemics had occurred, was hard and compact, Pettenkofer showed that his conclusions had been drawn from old and incorrect maps. He further had Settimio Monti, an Italian engineer, investigate the soils and the ground was found to be very foul. We must admire Pettenkofer’s enthu- siasm In his being always ready to visit and personally investigate any place that was supposed to possess characteristics that could not be explained by his theory. In this he certainly did not deserve Koch’s criticism that he merely distorted facts to prove his theories and did not actually study conditions. Disinfection. In 1854, Pettenkofer held that the ideal way to stop typhoid fever and cholera was to kill the germ, especially in the excreta, by means of disinfection. As late as 1866, he still placed disinfection 6 4 MAX VON PETTENKOFER at the head of the list of steps that should be taken.?® In his capacity of Gesundbeits- rath, 1873,%% he says nothing further about disinfection, for the epidemic of 1866 had shaken his faith in that measure and he came more and more to the view that neither the fresh nor the old excreta contain the poisonous germ. Even though the “x” be killed in the feces, this would not protect a “disposed locality” which could be infected with the “x” in some other way. Here again he is vague for he does not hazard even a guess as to how this might come about. Therefore he announced that he believed disinfection to be an entirely empirical procedure and one that cannot be measured. He said that in Hamburg they disinfected the excreta and the epi- demic stopped and that this was a favorite example of the bacteriologists who over- looked the Munich epidemic, in which the epidemic stopped at the same time of itself without any disinfection. The supposed rarity of the occurrence of cholera on shipboard was one of Petten- 165] MAX VON PETTENKOFER kofer’s chief arguments in favor of the essen- tial nature of the local conditions. Ships, he said, resemble immune places on land into which the disease may be brought but no epidemic result.!?*1?* In every instance in which cases of cholera were found on board ship, they have been brought from cholera infected localities. In other words, no cases occur in persons who have not been in cholera localities ashore. He gave as an example, the cholera outbreak on the British battleship Britannia lying off Varna in the Crimean War. There were many fatalities among the troops taken on board but none among the crew of the ship. Pettenkofer concluded that the soldiers had come in contact with infectious matter on shore where there was an epidemic, conveyed it on board, and then become ill from cholera in a manner quite comparable with the occurrence of the disease among those who visited an infected locality on shore and then going to a cholera-free place, develop the disease. The crew on the other hand may be likened to the inhabitants of a {66} MAX VON PETTENKOFER cholera-free place who do not become infected even though cases of the disease are introduced. In 1873, of 400 ships carrying 152,000 passengers from infected ports of conti- nental Europe to New York, only four had cases of cholera.®*122° Two ships had one case each, one had three cases and one had four cases. If cholera were contagious and not dependent on certain local condi- tions, surely, said Pettenkofer, more cases than this would have occurred on board. The few exceptions in which cases did develop on board are explained by Petten- kofer by the assumption that either the cases on shore had brought with them enough infectious material (he does not say how) not only to cause cholera in them- selves but in others as well, or else on dirty ships there might be enough soil for the development of the virulence of the germ, thereby resulting in the disease. This argument is fairly characteristic of Pettenkofer. He was fond of citing a certain number of instances which seemed to prove 467] MAX VON PETTENKOFER his point fitting the explanation to these cases. He offers no proof or even a sugges- tion as to how the individual from the shore who has been exposed to cholera brings with him enough infectious material to communicate the disease to another. It is of course to be borne in mind that Petten- kofer does not admit the possibility of a direct transfer of the disease from one indi- vidual to another. Though perhaps unsafe to hazard a guess, it seems almost certain that there must have been records of cholera epidemics on board ships at that time in which the evidence of direct transfer of the “germ” was undeniable. Pettenkofer believed that in addition to the specific organism causing the disease, which he called “x,” there is some other factor in the soil which contributes some- thing to the development of the germ (x) that is essential in order to produce the actual infectious material that causes chol- era. He called this factor “v.” It repre- sented to him the local and temporal conditions in the soil. This factor “vy” 68] MAX VON PETTENKOFER therefore represents the definite degree of moistening In a porous soil containing decaying organic material. The “vy” is the proper and necessary medium for the devel- opment of “x.” The process of the union of “x” and “vy” is one of “ripening” (Reifung), a procreation of the resistant form of the germ, or as it later came to be called, the evolution of toxicity. The sub- stance resulting from the union of “x” and “v,” Pettenkofer called “z.” In his study of the 1854 epidemic of cholera (Ref. 200, p.737), Pettenkofer studied each case in detail to ascertain the incuba- tion period. From the records of fatal cases he selected those that fitted into either of the following groups: (1) Those cases in which an individual from a heretofore cholera-free locality was suddenly brought into a highly infected cholera neighborhood and after a certain time developed the dis- ease; (2) Those cases in which an individual from an infected locality entered a cholera- free neighborhood and thereafter a “con- tact” (neighbor or member of the same 60 MAX VON PETTENKOFER household) became ill with the disease. He found that the time interval in the first group between the arrival of the individual and his development of cholera symptoms was from one to two days, average one and a half day. On the other hand the time of the “contact” case in the second group was from four to fifteen days, average eight and eight-tenths days. From these data he con- cluded that the infectious material, which results in the spread of the disease and of which man is the carrier, remains in such condition in the human body or is changed by him in some way, that for some days it is mert. Thus the man coming into the cholera neighborhood from a free locality comes down with cholera in one and a half days, but if the material is brought into the cholera-free locality it must remain in the soil some time (average eight and eight- tenths days) before becoming “poisonous.” (Ref. 2335, p. 114.) Emmerich considered this change in the soil a development of “growth energy’ (Wachtumsenergie). This he thought to be a development of its nitrous acid pro- 70] MAX VON PETTENKOFER ductive power. The nitrous acid production is essential to produce fatal cases, but the milder cases might be caused by contact. The cases selected by Pettenkofer to prove his point were, in the first group, only six of a series of thirty-six cases; in the second group, sixteen from a series of which the number is not given. He does not take the remaining cases into considera- tion at all. By such methods, cases might have been selected to prove almost any real or supposed epidemiological phenom- enon, but this was a practice at which Pettenkofer was an adept. Nigel: thought that two germs existed, one (the contagium) transported from the sick to the well but acting only in the presence of the second (the miasma), which is not transportable and is derived from the soil, rendering the individual suscept- ible to the disease. This was the diblastic theory and Pettenkofer was somewhat in sympathy with it as approaching his own, which, in contrast, was sometimes known as the monoblastic theory. 7 1 MAX VON PETTENKOFER Pettenkofer admitted that possibly in rare instances the “x” seems to act with- out the “vy,” ie., by direct passage from the sick to the well. He himself cited instances of this, but added that in his opinion these cases, if sufficiently analyzed, would be found to accord with his theory. Here, he said, we are dealing with the “2” of which but a minute quantity is necessary, or possibly the “x” had found some other factor that had the same effect on it as the “vy” from the soil, such as waste material or other filthy substance. Again we feel that there is no condition that Pettenkofer, by some argument or other, could not fit into his theory. As an additional proof of the essential quality of the “local conditions,” Petten- kofer makes the astonishing statement that cross infections never occur in hospitals for cholera patients. That is, cholera never occurs in a patient admitted to such a hospital for a condition other than cholera. The only exception is when the hospital is located in a cholera locality (Cholera- 72] MAX VON PETTENKOFER herd). In such cases the patients admitted for other conditions may develop cholera even though there be no cholera patients in the hospital at all. As an example, he cited the General Hospital at Calcutta which, he said, in spite of the admission of numerous cholera patients, never became a cholera focus. In an endogenous disease like smallpox, many unvaccinated physi- cians and attendants became infected, but with diseases like cholera and typhoid fever, there is no more to fear than with healthy persons. Nor is there any danger in handling the bodies of those dead of cholera. The mode of spread of cholera, said Pettenkofer, shows of itself that the disease Is not contagious. If it were contagious, it would spread out gradually from a central point via the chief avenues of travel and commerce, I1.e., roads, waterways and rail- ways. With the development of the railways its spread would be expected to be acceler- ated. Pettenkofer said that such was not the case because there are certain com- munities affected and others spared accord- {7 3 I MAX VON PETTENKOFER ing only to local conditions.®* On the other hand, if the disease were contagious there would be no immune places or times. Cunningham reported in India: (1) That despite the frequent introduction of the disease there remained great unaffected areas; (2) that the railroads had not increased the spread of the disease; and (3) that troops infected with cholera do not infect other than “disposed” localities. Similarly the movements of pilgrims and refugees have no effect.?*® Thus also in Europe, through carelessness in 1870-1871, thousands of soldiers with typhoid fever and dysentery were evacuated to all parts of Ger- many but no epidemicresulted (Voit,?*p. 81). In Prussia, during the epidemics of 1848 and 18509, there were twenty times as many persons affected in Posen as in Westphalia (Pettenkofer does not give the numbers). During the same period, similar differences were observed in different parts of Bavaria and Saxony. The epidemic was confined in a marked degree by river sheds and drainage areas. For example, on the great moors south 7 4] MAX VON PETTENKOFER of the Danube in Bavaria there was the greatest difference in neighboring villages with respect to cholera incidence. The low-lying villages were much more severely stricken than those highly situated, thus con- forming to Pettenkofer’s earlier observations. Pettenkofer said that Farr, the English statistician, ?®® was in error in thinking that the occurrence of cholera had anything to do with the height of the quarter of the city affected. The real determining factor, he said, was of course the condition of the soil. In Gibraltar, Pettenkofer had found that the highest part of the town was the section chiefly attacked, while on the other hand in Malta, the lowest and filthiest (moistest) part of the island was entirely free from the disease. 0110111 Even more striking proof of the effect of the soil, i.e., the local condition, was to be found in the case of the Laufen prison, to which Pettenkofer was especially fond of referring. During the 1873 epidemic, among the inmates of the prison (500 In number) over eighty died yet the disease 75} MAX VON PETTENKOFER did not attack any of the physicians, attendants, nurses, or the guard of sixty- seven soldiers,'**1%® mn spite of constant contact. The disease was much more pre- valent in the eastern half of the building than the western half. Similarly in the prison in Halle the men’s side was affected while the women’s side escaped. ?3* Among places which had remained im- mune, or relatively mmmune, to cholera notwithstanding commerce, were Multan in the Punjab,” Stuttgart,?*® Wiirzburg,?? Frankfurt am Main, Salzburg, Innsbruck, Freiburg i S. and a part of Nuremberg as already stated. To Pettenkofer, cholera patients and commerce with cholera-infested places seemed dangerous only in so far as these might act as a match or tinder to light the flame, but he compared the real danger, the local conditions, to the powder itself, say- ing that it is better to do away with the actual mine than with the fuse only. The burning match causes no explosion if there is no powder. (Voit,”* p. 117.) 76] MAX VON PETTENKOFER As Pettenkofer thought that no cholera could result from a direct transfer of the poison from the cholera patient to the healthy person, he considered all quaran- tine useless.!?® The disease being transmis- sible, it may be introduced into healthy localities not merely by the sick but also by the well. Thus quarantines are of no avail, for man cannot make a barrier that is germ proof. Besides this, it is an expen- sive procedure and restricts trade to such an extent that “many people would prefer an epidemic to a long restriction of their means of livelihood.” He thought that the money saved by not imposing a quarantine could be used to far better advantage in other sanitary work. He always laid much stress on the impor- tance of not frightening or exciting the people during an epidemic. One of his chief arguments against the contagionists was that they merely upset the people and made every man fear his neighbor instead of helping him. Here, he said, was one of the valuable influences of the 1836 cholera 77} MAX VON PETTENKOFER regulations, which did much good in calm- ing the people by assuring them that cholera is not contagious.?® SeAasoNAL CONDITIONS While some places are always free from cholera, others are free only at times. They may at other times be visited by severe epidemics. Even in places which have a “disposition” to cholera, the disease does not always occur, and when it does occur it is not always with the same severity. The “temporal disposition” is determined by the amount of moisture in the soil, pro- vided of course that the soil is of the proper type (porous with decaying organic matter in the interstices). The amount of moisture necessary to produce an epidemic is very exact, though Pettenkofer says there is no way of measuring it. The “x” will not develop in a soil that is too moist or too dry. The ground water level is a ready index by which the amount of moisture in the soil may be ascertained. When the ground water level 1s high, Pettenkofer assumes that the 478] MAX VON PETTENKOFER soil 1s too moist for the cholera germ to develop, but when this level is lowered, the moist subsoil becomes an ideal place for the “ripening” of the “x.” Pettenkofer’s conclusions regarding the ground water level and its significance were reached after his study of the 1854 epidemic. Consideration had previously been given to the subject. The Bavarian Academy had in 1762 offered a prize for a discussion of this subject in its relation to agriculture but the report had unfortu- nately been lost. Pettenkofer, although believing that the germ of cholera is given off in the evacuations of the patient, was at a loss to explain why it is that the dis- ease only occurs at certain times and in certain places, while it seemed probable that the distribution of the germ was much wider than the incidence of the disease. Von Voit tells us that Pettenkofer attempted to account for this variable factor in many ways but finally decided that it must in some way be connected with the changes in the ground water level. He began to 70} MAX VON PETTENKOFER measure this change in the wells of Munich by means of pipes set into the soil and also to study the records of former years, show- ing first that there had been a lowering of the level in the cholera years 1836 and 1854.7 He, however, warned against the assumption that the conditions existing in Munich prevailed everywhere. In 1859, he outlined a program for the investigation of the local and temporal con- ditions affecting the spread of cholera and typhoid fever in various countries, localities and even single houses, based on the official death certificates. He was particularly desirous of studying the conditions of the soil in immune and affected places and also the drinking water in each. The result of his studies was his adoption of the ground water theory and the rejection of the belief that drinking water played a part. Pettenkofer’s arguments regarding the influence of the level of the ground water were greatly strengthened by the observa- tions of Ludwig Buhl in 1865 on the corre- lation of the fatal cases of typhoid fever in {80> MAX VON PETTENKOFER Munich and the lowering of the ground water level.??® Buhl's paper created much interest especially when his correlation held good for the following year.!?® Pettenkofer’s friend, the mathematician Ludwig Seidel, in two papers®®?’ offered evidence that the probability of there being a causal connection between the ground water and the typhoid mortality was to the probability of their being no such connection as 36,000 to 1. This correlation, says Voit, continued to exist in Munich for more than thirty years and only ceased when the purification of the water supply and cleansing (Verun- reiningung) of the soil by the application of sanitary measures removed this factor. (Voit,2™ p. 85.) Soyka disagreed with Pet- tenkofer’s conception that reduction of typhoid mortality was due to the drainage (sewerage) of the soil. He held that it was due to prevention of the causative agent penetrating into the soil after installation of the sewers. (Weyl, ?"® p. 200.) According to Pettenkofer, much light was thrown on the factor of “temporal 48 1 I MAX VON PETTENKOFER disposition” by his study of cholera in India.'%1% The disease often varies with the time of year and with the rainfall. Even in places where cholera exists at all times (e. g., Calcutta and Bombay), the disease is three times as prevalent in the dry months as in the wet. There 1s a remarkable paral- lelism between the cholera incidence and the rainfall, the highest cholera incidence occur- ring simultaneously with the lowest rainfall. Pettenkofer’s explanation was that the excessive rainfall makes the ground too wet for the ripening of the “x” but as the earth dries out the rate rises. It is quite otherwise in regions where cholera is not endemic (e. g., Lahore). There cholera comes with the rains and decreases as the dry sea- son sets in, August being the time of both the maximum cholera incidence and rain- fall. But in Lahore the rainfall is only one third as great as in Calcutta so that in the dry seasons the soil is too dry for the devel- opment of the “x,” the necessary moisture for which is only to be had with the advent of the rainy season. In Madras there is a 8 2 < ¢ sl 2 0 No ih Getabier ember | December Januar | 1873 = Tinglicho (holeraerkrankungen Fagliche Regenmenge in Villinsetern PETTENKOFER’S GRAPH SHOWING CHOLERA MORBIDITY AND GROUND WATER LEVEL IN MUNICH, 1873-1874. FR ML mie Fo IY 3d andl Fih aE 0 [Fo Cs, “it ee I a A itm fT, rr nbd el 5 =» i MAX VON PETTENKOFER double rhythm, i. e., a spring and a summer cholera on account of the character of the local rainfall. The fallacy of an argument like this is apparent. Pettenkofer without having been to India assumed that certain relations existed and fitted the conditions to his theory. There were cases of the importance of the temporal element in Europe also. In Prussia, during the twelve year period 1848 1859, the smallest number of deaths in any month occurred in April. From this time till the middle of September, the number increased 620 fold and then gradually fell off until the middle of March. Similar con- ditions prevailed in Saxony®* and Bavaria. In Genoa the epidemics always declined during July and September in spite of the introduction of the germ. The varied rainfall likewise changes the incidence. In Munich the cholera maximum fell in September when the soil was dryest. It is noteworthy that the cholera years 1836, 1854 and 1873 were unusually dry years. In the year 1873— 1874 two epidemics occurred. The summer epidemic of 1873 began in the middle of Aug- 185] MAX VON PETTENKOFER ust, declined in September, and by the first of November only a few cases remained and the epidemic was officially declared at an end. However in the middle of November it began anew and the winter epidemic of 1874 was greater than the summer epidemic of 1873. Pettenkofer used this epidemic to illustrate the effect of the temporal factor. In 1873, the ground water level had been quite different from the normal. Usually the highest point was reached in June, after which it declined reaching the low level in January or February. In 1873, the high point was reached in June but thereafter it fell so rapidly that the low point was reached in July. Thereafter increased rainfall caused it to go up again in the middle of August so that the cholera almost disappeared. Then the soil again dried out and cholera recurred. (See graph.) This incidence, said Petten- kofer, is quite like the growth of fungi in the forests, which grow only when the proper degree of moisture is found in the soil. Similarly wooden piles driven into water- covered earth decay only where the air and 86] MAX VON PETTENKOFER water meet, 1. e., where the correct amount “of moisture is found. Much interest is attached to the places that escape an epidemic on one occasion and are attacked during another epidemic. Dur- ing the Bavarian epidemic, for example, one section of a barrack in Friesing escaped typhoid fever entirely and the other had many cases, while in a subsequent epidemic the conditions were reversed, 1. e., the part formerly free was afflicted while the part that had been exposed escaped. (Voit, p. 90.) Pettenkofer says that there had been some change in the soil conditions but does not say what the change was. The best example of all was the city of Lyons.®* This crowded industrial center, situated between two well-known cholera foci, Paris and Marseilles, and in constant communication with them, escaped the epidemics of 1831-1836, 1849 (during which there was an infected regiment quartered in the city), 1865-1866 and 1884. Only in 1854 was Lyons affected by the epidemic (Voit,?"* p. 36). Certainly, said Pettenkofer, the germ {87F MAX VON PETTENKOFER must have reached the city and the individ- ual disposition to contract the disease must have existed. The drinking water was no better than that of other cities, or so he assumes, and similarly the soil was not less fouled. It also possessed satisfactory sewers so that some change in the condition of the soil can be the only explanation. As a general rule, he says, the soil at Lyons is unsuit- able for the development of cholera epi- demics but in 1854 there had been very little rainfall and the level of the Rhone was abnormally low. Thus the soil could develop the degree of dryness necessary for cholera. This explanation would, he said, account also for the existence of a certain number of immune areas in the city, as the soil was not subjected to a uniform rate of drying. It will be noted that while Pettenkofer says that the drinking water, soil, etc. were not different from those of some other places, he offers no evidence to prove this. Inpivipual CoNDITIONS There is evidently another factor in the causation of cholera and similar diseases, 88] MAX VON PETTENKOFER that of individual susceptibility or ““dis- position.” The disease certainly does not manifest itself in all people alike even under similar conditions. Some individuals seem to be “predisposed.” No explanation of this factor was reached by Pettenkofer though he suggested that anything that disturbs the normal physiological processes or impairs the general health predisposes to cholera. Among other contributing fac- tors he suggested that the following might be of importance: advanced age, poverty, weakness, abnormal water content of the body, bad air, unclean water, defective nutrition, dietary errors, bad food, improper clothing, filthiness, physical or mental strain, intemperance, excesses of all kinds, psychic effects, depressing states of mind, fear, and anything productive of diarrhea. (Voit,?* p. 100.) THE DRINKING WATER THEORY Pettenkofer’s opponents held that the chief medium of transference of the cholera germ was the drinking water. When he {89} MAX VON PETTENKOFER first undertook his investigation of the epidemiology of cholera, Pettenkofer was of this opinion himself. But as his work progressed, he got further and further away from this idea. Munich was an excellent place to study this question for there were several private water purifica- tion and distribution companies, with pa- trons side by side. However after a careful house to house survey, Pettenkofer was unable to find any difference in the spread of the disease among the patrons of the several systems. His early decision that drinking water played vo role in the causa- tion of cholera had an important bearing on his future work in that it directed his studies into other channels, and being convinced that he had settled with the question of drinking water for all time, he spent much valuable time in picking flaws in the arguments of others instead of directing his energies into constructive research in this regard. 83 In his well-known report on the water supply of South London and its connection Jook MAX VON PETTENKOFER with the cholera epidemic of 1848-1840, John Snow?%%%7% showed that there was a great difference in the incidence of the disease between the users of the water of the Lambeth Company, which took in its supply at a distance up the Thames beyond the influence of the tide and out of reach of the sewage of the metropolis, and those of the Southwark & Vauxhall Company, whose water was taken from a part of the Thames which contained the sewage of the city. The users of the waters were intermixed and a comparison of the incidence of the disease between the two groups was illuminating. In the first four weeks of the epidemic, the proportion of deaths among the Lambeth patrons to those among the Southwark & Vauxhall patrons was 1:14. In the next three weeks, it was 1:7.6 and in the last seven weeks 1:4.8. The disproportion naturally decreased as the epidemic progressed on account of the mixing of the people. This epidemio- logical study of Snow was one of the strongest of the earlier evidences in favor for} MAX VON PETTENKOFER of what Pettenkofer always termed “the drinking water theory.” In commenting on Snow’s paper, Pettenkofer said that it was In no way a refutation of his theory since the water was naturally used for cleaning purposes and a part must needs have reached the soil. Thus the clean “x” free) water of the Lambeth Com- pany would not have contaminated the soil, while the foul (“x containing) water of the Southwark & Vauxhall Company would have done so, thereby resulting in the formation of “z” which caused the cholera (Voit,”* p. 103). Later on Letheby doubted the accuracy of Snow’s observa- tions and attempted to show that there had been considerable confusion, so that a house which was registered in the Lambeth Company really drew its water supply from the mains of the Southwark & Vauxhall Company and vice versa. Pettenkofer received this report of Letheby with great satisfaction and gave it much publicity. (Ref. 191, pp. 198, 863.) oz] Jc} A CHART SHOWING THE VARIATION IN THE GROUND WATER AND IN THE MORTALITY FROM TYPHOID FEVER IN Munich. MAX VON PETTENKOFER On the other hand, the contagionists replied by citing instances in which there was apparently a connection between the drinking water and the incidence of the intestinal diseases. For example Roveredo in 1845 installed a new water supply and typhoid fever disappeared; to which Petten- kofer replied that in a letter from the local engineer he had been informed that there had been no change in the incidence of the disease (Voit,”* p. 103). In Elsterberg, in Saxony, typhoid fever and cholera only existed in a certain section of the town where there was a well known to be pol- Iuted, while the rest of the town had good water. However, Giinther showed that nobody used the polluted water on account of its disagreeable taste (loc. cit.). (Emmer- 1ch,% p. 524.) In 1865»! typhoid fever disappeared from Munich and all of Pettenkofer’s opponents said that it was due to the introduction of the new Thalkirchen water supply which had been installed chiefly on account of Pettenkofer’s recommenda- Jos] MAX VON PETTENKOFER tions. However after this the greatest epidemic of thirty years occurred.’ Fort William in Calcutta had had much cholera®? but after the new sanitary regu- lations went into effect and the new water supply was used, there was no more cholera. Pettenkofer showed that there had also been other improvements at the same time and that the reduction in cholera actually began before the improvement in the water supply. In the case of the water of the Broad Street pump in Golden Square, London, to the use of which Snow traced so many cases of cholera in the epidemic of 1854, Pettenkofer’s comments were: A second instance in London was that with which the name of Dr. Snow is associated. Golden Square, a part of London with very deficient drainage, was the scene of a severe epidemic of cholera in 1854. The epidemic con- centrated itself in Broad Street. There must have been some reason for this, and the reason must be discovered. Where Golden Square and Broad Street stood was formerly a place for burial Jos} MAX VON PETTENKOFER for individuals dead of the plague. This pest-blast of a former century could walk from its grave in A. D. 1854 like the Ghost in Hamlet. But a narrower inspection proved that the old pest field and the new cholera field were not exactly coextensive. Now, however, another fact was brought to light, which led to the substitution of the drinking water as the cause. In the middle of Broad Street there stood a pump of which the water was much esteemed on account of its freshness. At the end of August, whilst the cholera was raging, it was found out that many sufferers had drunk of the pump water, but the fact was not sufficiently decisive, and so a pathological experiment was required. In Broad Street there was a percussion cap factory belonging to Mr. Eley. The persons of this estab- lishment suffered from cholera, and many of them died. Mr. Eley remained well, but he did not live at the factory, though he went there daily and returned home to Hampstead after business, and there lived with his mother and niece. His mother, who formerly lived in Broad Street, had a great liking for the water of the pump-well, which was shown in the fact that her son daily took home the water for his mother and niece. In Hampstead there had been Job] MAX VON PETTENKOFER no case of cholera until the mother and daughter fell ill and died of cholera without having any other communication with Broad Street than through the means mentioned. What more is wanted? Who can doubt any longer? An experi- ment on two human beings with a disease which animals are not susceptible to! A sad privilege! Never before had facts received a more frivolous interpretation. Suppose, for a moment, that Mr. Eley had gone to and from Hampstead to Broad Street without having taken the water to his mother and niece; and, further, that they had become ill of the cholera without having drunk the pump water, would it have been imagined that the cholera had been carried by the son, who remained in good health? The contagionists would probably reply that Mr. Eley may have had cholera in a mild form. The localists would say that a poison locally ori- ginated might be passed on by healthy people without giving signs of illness in them. In 1854, for example, a young lawyer went from Munich to Darmstadt, where his father resided. Up to that time the father had never lived out of Darmstadt, and Darmstadt was as free from cholera as Hampstead, and the distance from Munich was much greater than Hampstead from for} MAX VON PETTENKOFER Broad Street. The lawyer was as well in health as Mr. Eley had been, but the lawyer’s father fell ill and died of cholera. There was no other factor in the case than the return of the son from Munich. Darmstadt enjoyed an immunity from cholera as great as that of Lyons, Versailles, Stuttgardt, and many other larger cities. In 1854, a workman went home from the Exhibi- tion of Munich to Darmstadt, where he fell ill and died of cholera without the disease being spread to any other house, and no means for disinfection or isolation had been adopted. In 1866 Prussian troops were quartered in Darmstadt, and brought the cholera with them. About thirty of the soldiers became ill with cholera, and many of them succumbed; again, none of the inhabitants of Darmstadt had the disease. It must be admitted that Mrs. Eley might have been infected through the intercom- munication of her son, just as the lawyers father had been without the intervention of drinking water. The argument in favour of the drinking water theory rests on the fact that the cholera ceased when the supply of water was cut off; but no notice was taken of the great majority of cases in which the water springs were not closed and the supply of water not cut 108] MAX VON PETTENKOFER off, and yet the epidemics came to an end. Again, in Broad Street the pump handle was not taken off till Sept. 8th. Now, an examination of the facts will show that the cholera was already subsiding. In Broad Street, on August 31st, there were 31 cases of cholera; on Sept. 1st, 131 cases; on the 2nd, 125; on the 3rd, 58; on the 4th, 52; on the 5th, 26; on the 6th, 28; on the 7th, 22; and on the 8th, 14. Just as occurs in India and elsewhere, a violent epidemic generally subsides rapidly (Ref. 191, p. 863). While denying the drinking water theory of cholera, Pettenkofer was of the opinion that bad drinking water is of itself harmful. He said that he was more in favor of pure water ‘than the drinking water theorists themselves, though always insisting that cholera would occur even if the purest of water were used exclusively. He said that the danger from bad water lay not only in its use as a beverage, but also when it was used in cooking, washing, cleansing floors, and so forth. The danger lies, he said, in that the foul water may serve as a medium for pathogenic microorganisms and fool MAX VON PETTENKOFER that when the water is used repeatedly there accumulates on the surfaces washed enough material to serve as a breeding place (Brutstitte) for the pathogenic germs from whence they can infect man. (Voit, 2" p. 106.) He therefore urged that only pure water be used even for such pur- poses as street cleaning, and so forth, saying that the drinking water theory was not sufficient from a hygienic standpoint but that the localistic theory was more satisfactory since it provided good water for all purposes and not merely for drinking. The arguments of Pettenkofer and his followers who depended entirely on epi- demiological evidence, with Koch and his followers who depended entirely on bac- teriological evidence, show how important it is not to view the subject from one angle only. Had either side been less uncompro- mising, science would have been benefited and the interrelationship of the two sub- jects would have been sooner recognized. But each insisted that the other’s conclu- sions were based merely on coincidences 100} MAX VON PETTENKOFER and said that one theory must be:accepted in its entirety and the other rejected: “Fach: fell into the error of generalization: fromi a’: few cases. i The following tabulated comparison of the views of Pettenkofer and of Koch on the epidemiology of cholera is taken from data in Emmerich’s monograph :2% Koch’s Views 1. Same. Pettenkofer’s Views 1. The Vibrio of Koch is the cause of cholera. 2. Cholera is contagious, and even fatal cholera 2. Fatal cholera is not contagious, I. e., Is not transmitted di- is transmitted directly rectly from man to from man to man by man by the dejecta the dejecta which con- and no epidemic can result from the trans- mission of the dejecta because the same (ac- cording to Emmerich) has, by its passage through the intestine, lost some of its toxic properties. Jor} tain the Vibrio, so that contact may pro- duce “chain infec- tion” and epidemics. MAX VON PETTENKOFER 3..-Fhe. cholera Vibrio Fh ectogenously * tan porous’ “fouled soil “tthe” tine when the ground water sinks. The non-toxic cholera bacilli in the dejecta attain their full tox- icity in the soil, and only these bacilli from the soil can cause epidemics. . The spread of cholera depends chiefly on the condition of the soil. There are places with porous soil which are disposed to cholera and there are other places which have rocky or impervious soil which are im- mune. .Cholera shows a marked seasonal per- Jroz} 3. 5. Since the typhoid and cholera bacilli are ob- ligate parasites and are only capable of development in the human body, the soil fplays no important part. For the occur- rence of an epidemic only the cholera bacil- lus and the susceptible individual are neces- sary. . The spread of cholera as well as the dis- position and immun- ity of certain local- ities depends not on the soil itself but on personal factors such as general health, hab- its and customs such as cleanliness in re- gard to food and drink, etc. The seasonal period- icity of cholera and MAX VON PETTENKOFER iodicity, for example in Prussia between 1848 and 1859 there were only fifty cases in the first half of April but 31,048 in the first half of Sept., a ratio of 1:620. This can only be explained by external influences such as rain, dryness, temperature, etc. and, according to Emme- rich, the production of an upward capillary stream in the soil. . Severe cholera epi- demics always fall in times of drought when the ground water sinks. No epidemic can occur in a period of rain. Heavy rains can terminate cholera epidemics by causing the ground water to rise. There are how- ever other causes for 4103} the increase in the incidence In summer and autumn is due to the fact that people drink more water, eat more fruit and use more ice then so that by reason of gastro- intestinal upsets they are debilitated and more susceptible to cholera. 6. The occurrence of cholera epidemics in time of drought is due to the low water level of rivers and the lowering of the ground water In springs so that the dissemination of the cholera bacilli is fur- thered since the filth is less diluted and MAX VON PETTENKOFER the termination of epi- demics such as soil immunity from accu- mulation of metabolic products of the chol- era bacillus (Choler- ase) in the superficial layers of the soil. . Drinking water plays no role in cholera epi- demics. The explo- sive character of epidemics might be accounted for by the sudden development of the “disposition” in the soil of several quarters of a city at the same time. . The best cholera pro- phylaxis lies in the removal of the local “disposition” of the porous soil of places attacked, by drainage, water purification, J rog]r the rivers carry it off less quickly. . The explosive char- acter of cholera epi- demics is explained by the drinking water. . The best weapon for attacking an epidemic is the detection of the first case by bacter- iological examination of stools, etc. and the isolation of the MAX VON PETTENKOFER etc. also paving and same and rendering asphalting of streets, them harmless. courtyards, etc. The detection of the so- called “first case” is of no importance since if the local and tem- poral dispositions re- main it is impossible to detect all cholera Vibrios. In discussing the above Emmerich said that only one of the theories can possibly be true, yet in the instruction in hygiene and in the public health practices an effort was being made to compromise. He thought that Koch had taught nothing new except that the vibrios might be detected in the dejecta. The drinking water theory itself was very old. It is foolish to say that drinking water predisposes one to the disease, else soldiers, bakers and others engaged in trades requiring them to work in hot places, would have a higher incidence than others. Wells are really more fouled (not less so), in rainy weather than in dry. ros} MAX VON PETTENKOFER He also denied that the bacilli of cholera and typhoid fever are obligate parasites in that they can live for some time in soil of “disposed” places. MacNamara reported an instance in the 1861 epidemic in India of nineteen persons who drank the rice water stools from a case of cholera by mistake, five of them becoming ill with cholera. (Ref. 260, p. 196.) Pettenkofer said it was unfair to conclude from this that there is any con- nection between this act and the disease since the other fourteen persons should be taken into consideration. This is just what Pettenkofer did not do in the majority of his arguments. He frequently selected a number of cases that illustrated some point and ignored the others of the series. J 106] Iv CONCLUSION ETTENKOFER is entitled to a place in the ranks of the great men of science on account of his work m chemistry and physiology which is still accepted. His work in epidemiology, too, is important, but for a different reason. His great hypothesis regarding the etiology of cholera and typhoid fever is no longer tenable but in so forcefully defending his ideas, he stimulated others to great discov- eries. His pupils were many and their work has added much to the sum of human knowledge, so that, in a measure, Petten- kofer shines by reflected light. In the final analysis it cannot be denied that he effected a wonderful improvement in Munich, which thereafter served as a model for other cities not merely from the standpoint of beauty but also of health. Like Pasteur, his versatility was marvel- ous. It is difficult to find a man who was Jro7f MAX VON PETTENKOFER able to achieve so much in so many totally different fields. He is of course best known as an apostle of good water, fresh air and proper sewage disposal, but it is upon his chemical and physiological studies that his reputation should rest. His logic was not of the best. He made frequent use of empirical generalization which, however, he condemned in his oppo- nents. He seems withal to have been most conscientious and to have believed thor- oughly in his teachings. His willingness to visit any place where conditions prevailed that seemed not to fit into his theory shows an openmindedness that one would otherwise be inclined to doubt at times. He had the courage of his convictions, however, as demonstrated by his experi- ment in swallowing the cholera bacillus. It is not easy to criticize his various views since our conception of the problem today 1s based upon other ideas. To verify or refute the facts upon which he relied to prove his arguments, is well nigh impos- sible after such a long interval of time. J 108 BIBLIOGRAPHY PUBLICATIONS BY PETTENKOFER . Sichere und einfache Methode das Arsenik mittelst des Marsh’schen Apparates ent- wickelt von allen andern dhnlichen Erschei- nungen augenfillig zu unterscheiden. Buch- ner’s Repert. f. Pharm., 1842, 1xxvIi, 289; 1844, LxxX11, 328. . Ueber die Verwendung getrockneter Him- beeren. Buchner’s Repert. f. Pharm., 1842, LXXVII. . Ueber eine gerichtliche chemische Unter- suchung. Buchner’s Repert. f. Pharm., 1842, LXXVIIL . Ueber Mikania guaco. Diss. Inaug. Miinchen, 1844; Buchner’s Repert. f. Pharm., 1844, LxxxvI, 280. . Ueber eine grosse Menge Hippursiure in Men- schenharn. Liebig’s Ann., 1844, ri, 86. Heller's Archiv, 1845, p. 121. Journ. de Pbarm., 1843, vii, 280. . Ueber einen neuen stickstoffhaltigen Korper im Harn. Liebig’s Ann., 1844, L11, go. Heller's Archiv, 1845, p. 124. roo MAX VON PETTENKOFER 10. 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Miinchen, 1869. 104. Boden und Grundwasser in ihren Beziehungen zu Cholera und Typhus. Ztchr. f. Biol., 1869, v, 310. rar] MAX VON PETTENKOFER 105. 106. 107. 108. 109. 113. 114. Ueber den Stoffverbrauch bei einem leuk- mischen Manne. (With Voit.) Ztschr. f. Biol., 1869, v, 310. Respirationsversuche am Hunde bei Hunger und ausschliesslicher Fettzufuhr. (With Voit.) Ztschr. f. Biol., 1869, v, 360. Entgegnung. Aerztl. Intellbl. 1869, No. v. Causes of Cholera. Med. Press er Circ., Lond., 1869, VII, 405. Die Choleraepidemie des Jahres 1865 in Gibraltar. Ztschbr. f. Biol., 1870, v1, 95. . Monatliche Zusammenstellungen iiber Temper- atur und Feuchtigkeit der Luft, Regenmenge und vorherrschende Winde in Gibraltar vom Jahres 1853 bis 1867. Ztschr. f. Biol., 1870, vi, 120. . Die Choleraepidemien auf Malta und Gozo. Ztschr. f. Biol., 1870, v1, 143. . Bemerkungen zu Dr. Buchanan’s Vortrag “On Pettenkofer’s Theory, etc.” Ztschr. f. Biol., 1870, v1, 513. Beantwortung der Frage: ob nach Maasgabe der Frankfurter Lokalverhiltnisse der Ein- fiithrung der Abtrittsstoffe in die neu erbauten Kanile vom sanitiren Standpunkt aus Bedenken entgegenstehen? Ztschr. f. Biol, 1870, VI, 544. Ueber den Kohlensduregehalt der Luft im Gerdllboden von Miinchen. Sitzber. Miinch. Akad., 1870, 11, 304. Jr22] MAX VON PETTENKOFER 115. 116. 117. 118. 119. 120. 121. 122. Observations on Dr. Buchanan’s lecture on Prof. Pettenkofer’s theory of the propaga- tion of cholera and enteric fever. Med. Times ¢r Gaz., Lond., 1870, 1, 629; 661; 687. Verbreitungsart der Cholera in Indien. Nebst einem Atlas von 16 Tafeln nach J. Bryden. Braunschw., 1871, 121 pp. Aerztl. Int. Bl, Miinch., 1871, xvi, 614. Typhus und Cholera und Grundwasser in Ziirich. Ztschr. f. Biol., 1871, vii, 86. Ueber die Zersetzungsvorginge im Thier- kérper bei Fiitterung mit Fleisch. (With Voit.) Ztschr. f. Biol., 1871, v11, 433. Ueber Bestimmung der Kohlensiure in Trink- wasser. Sitzber. Minch. Akad., 1871, p. 170. Ueber Kohlensiuregehalt der Luft im Boden (Grundluft) von Miinchen in verschiedenen Tiefen und zu verschiedenen Zeiten. Sitzber. Miinch. Akad., 1871, p. 276. Ztschr. f. Biol., 1871, v1, 395; 1X, 250. Chem. Soc. Journ., 1873, x1, 361. Ueber die Aetiologie des Typhus. Miinchen, 1872. Beziehungen der Luft zu Kleidung, Wohnung, und Boden. Drei pupulire Vorlesungen gehalten im Albert-Verein zu Dresden am 21, 23, u. 25 Marz 1872. Braunschw., 1872. 115 pp. fra} MAX VON PETTENKOFER 123. 124. 125. 126. 127. 128. 120. 130. 131. Ueber Cholera auf Schiffen und den Zweck der Quarantinen. Ztschr. f. Biol., 1872, viii, 1. Zur Choleraepidemie auf dem “Renown.” Ztschr. f. Biol., 1872, viii, 204. Ueber den gegenwirtigen Stand der Cholera- frage und iiber die nichsten Aufgaben zur weiteren Ergriindung ihrer Ursachen. Ztschr. f. Biol., 1872, vii1, 492. Auszug aus den Untersuchungen von Dr. Douglas Cunningham in Ostindien, iiber die Verbreitungsart der Cholera. Ztschr. f. Biol., 1872, vir. Ueber ein Beispiel von rascher Verbreitung specifisch leichterer Gasschichten in dar- unter liegenden specifisch schweren. Sitzber. Miinch. Akad., 1872, 11, 264. Ztschr. f. Biol., 1872, 1X, 245. Ueber Bewegung der Typhusfrequenz und des Grundwasserstandes in Miinchen. Sitzber. Minch. Akad., 1872, 11, 60, 107. Ueber den Werth der Gesundheit fiir eine Stadt. Braunschw., 1873, 63 pp. Ueber den gegenwirtigen Stand der Cholera- Frage. Miinchen, 1873. Was man gegen Cholera thun kann. Miinchen, Oldenbourg, 1873. Indian Med. Ann. Sc., Calcutta, 1875, xvi, 1. Am. Pub. Health Ass. Rep., N. Y., 1873, 1873, 1, 317. Jr24] MAX VON PETTENKOFER 132. 133. 134. 135. Ueber die Zersetzungsvorginge im Thier- kérper bei Fiitterung mit Fleisch und Fett. (With Voit.) Ztschr. f. Biol. 1873, 1x, 1. Chem. Soc. J., 1873, x1, 1047. Ueber den Kohlensiuregehalt der Grundluft im Gerdllboden von Miinchen in verschied- enen Tiefen und zu verschiedenen Zeiten. Ztschr. f. Biol., 1873, 1, 250. Ueber die Zersetzungsvorginge im Thier- korper bei Fiitterung mit Fleisch und Kohle- hydraten und Kohlehydraten allein. (With Voit.) Ztschr. f. Biol., 1873, 1x, 435. Der neueste Bericht des Sanitary Commis- sioner Dr. James M. Cunningham, iiber die Cholera 1872 in Indien. Ztschr. f. Biol., 1373, 1%, 4it. . Die Grundwasserbeobachtungen in Miinchen im Vergleich mit denen in Berlin. Berl. klin. Webnschr., 1873, No. iii. . Untersuchungsplan zur Erforschung der Ur- sachen der Cholera und deren Verhiitung. Deutsch. Reichsanzeiger, 1873. . Ueber Nahrungsmittel im Allgemeinen, und iiber den Werth des Fleischextracts als Bestandtheil der menschlichen Nahrung insbesondere. Ann. Chem. Pharm., 1873, cixvi, 271. Dutch translation, Haarlem, 1873. French translation, Lille, 1873. Jr25f MAX VON PETTENKOFER 139. 140. 141. 142. 143. 144. 145. 146. 147. Ueber die Bedeutung der Kohlehydrate in der Nahrung. (With Voit.) Sitzber. Miinch. Akad., 1873, p. 273. The relations of the air to the clothes we wear, the house we live in, and the soil we dwell on. Lond., 1873. Zum Gedichtnis an J. v. Liebig. Braunschw., 1874. 40 pp. Antrag betreffend Einrichtung fortlaufender meteorologischer Beobachtungen in einer Anzahl von Orten Westasiens und Aegyptens. Internat. San. Confer. in Wien, 1874. Ueber die Abnahme der Typhussterblichkeit in der Stadt Miinchen und iiber das Trink- wasser als angebliche Typhusursache. Deutsch. Vrtljschr. f. off. Gsndspflg., 1874, v1, 233. Ist das Trankwasser Quelle von Typhus- Epidemien? Ztschr. f. Biol., 1874, X, 439. On the recent outbreak of Cholera in Munich. Med. Times er Gaz., 1874, 1, 582. Sul modo di propagazione del colera nelle Indie; resultati ottenuti dalle recerche etiolo- giche piu recente fatte nell'India. Clinica, Napoli, 1874, 1, 49, 57, 65, 73, 89, 1875;,11, 9; 19, 35, 59, 87, 135, 167, 177. Vstupitelnaya raich’k’ obsuzhdeny u pro- grammi izslaidovaniya uslovii maistnago i vremennago razvitiya tiphoznikh epidemii. Zdorovje, St. Petersb., 1874-35, 1, 585. 126} MAX VON PETTENKOFER 149. 150. I51. 152 153. 154. 155. . Die Cholera-Epidemie in der k. bayrischen Gefangenanstalt Laufen a. d. Salzach. Be- richt der Cholera Kommission fiir das Deut- sche Reich. Berlin, 1875. 108 pp. Kiinftige Prophylaxis gegen Cholera nach den Vorschliigen in dem amtlichen Berichte des k. bayr. Bezirks- und Stadtgerichtsarztes Dr. Frank. Miinchen, 1875. 123 pp. Tr. San. Rec., Lond., 1873, 111, 35. Ueber ein Reagens zur Unterscheidung der freien Kohlensdure im Trinkwasser von der an Basen gebundenen. Ztschr. f. Biol., 1875, x1, 308. Sitzber. Miinch. Akad., 1875, v, 55. Ueber den Kohlensiuregehalt der Luft in der Iybischen Wiiste iiber und unter der Boden- oberflache. Ztschr. f. Biol., 1875, x1, 38I. Sitzber. Miinch. Akad., 1874, 1v, 339. Chem. Soc. J., 1876, 1, 891. Die Cholera-Prophylaxis in Miinchen von Dr. Frank, besprochen von Pettenkofer. Aerat. Int. Bl., Miinch., 1873, xx11, 370. Cholera, how to prevent it. Lond., 1875. Vortrige iiber Canalisation und Abfuhr. Miinchen, 1876. Schreiben an den Vizeprisidenten der Vor- bereitungscommission des Ix. internat. statis- tischen Congresses zu Budapest, betreffend Cholerastatistik. Programm des Congresses. 11. Section, Budapest, 1876. 127} MAX VON PETTENKOFER 156. Die Cholera 1875 in Syrien und die Cholera- prophylaxe in Europa. Ztschr. f. Biol., 1876, XII, 102. 157. Populire Vortrige. Miinchen, 1877, 255 pp. 158. Outbreak of cholera among convicts. An etiological study of the influence of dwelling, food, drinking-water, occupation, age, state of health, and intercourse upon the course of cholera in a community living in precisely the same circumstances. Lond., 1878. 106 pp. 159. Auftreten und Verlauf der Cholera in dem kéngl. bayrischen Strafarbeitshause Reb- dorf, in dem k&ngl. bayrischen Zuchthause Wasserburg und in dem kongl. bayrischen Zuchthause Lichtenau; und die Cholera-Epi- demien in den beiden Civil-Krankenhéusern und das Verhalten des Militir-Kranken- hauses und der Kasernen von Miin- chen wiihrend der Epidemie 1873-4, nebst Nachtrag zum Berichte iiber die Cholera- Epidemie in der kongl. bayrischen Gefan- genanstalt Laufen. Berlin, 1877. 98 pp. 160. Neun itiologische und prophylaktische Sitze aus den amtlichen Berichten iiber die Choleraepidemien in Ostindien und in den Vereinigten Staaten v. N. Amerika. Deutsche Vrtlyschr. f. ff. Gsndspfige., Braunschw. 1877, 1x, No. 2. English translation, Prac- titioner, Lond., 1877, xvi11, 135, 204. 128] MAX VON PETTENKOFER 161. 162. 163. 164. 166. 167. 168. Vorldufige Mittheilung {iber das Verhalten der Milch auf Thonplatten und iiber das Verhalten der Casein- und Fettbestimmung in der Milch (Julius Lehmann). Sitzber. Minch. Akad., July 7, 1877, p. 263. Bemerkungen zu einem Bericht des Herrn Briquet an die franzésiche Akademie der Medicin iiber die sogenannte Choleraboden- theorie. Deutsch. med. Wchnschbr., Berl., 1877, mn, 561, 573, 585. Bemerkungen zur Kritik des Hrn. Prof. Wagner iiber die Vorarbeiten zur Wasserversorgung Miinchens, 1877. Trinkwasser und Cholera. Zeitschr. f. Biol., 1878, xiv, 297. French translation. Sur Pétiologie et la prophylaxie du cholére. Rev. Med. de I'Est, Nancy, 1878, 1x, 67; 111. . Theorie des natiirlichen Luftwechsels von G. Recknagel. Sitzber. Minch. Akad., July 6, 1878, p. 424. Was ist und was will “Gesundheitslehre”? Gartenlaube, 1878, No. xx. Ueber Wasserversorgung. Deutsche Rev., 1878. Disinfektion von Schiffen, Bericht iiber einen Versuch der Disinfektion eines geschlossenen Raumes durch schweflige Siure, durch Verbrennen von Schwefel in der Luft des- selben. Versffentl. d. k. deutsch. Gandtsamts, Berl., 1879, 11. Jr29] MAX VON PETTENKOFER 169. 170. 171. 172, 173: 174. 175. 176. 177. 178. 179. Zur Frage der Ausscheidung gasférmigen Stick- stoffs aus dem Thierkérper. Sitzber. Miinch. Akad., 1881, x1, 270. (With Voit). Ztschr. f. Biol., 1880, xv1, 508. Ueber die Bewegung der Luft in den Sielen von Miinchen. Sitzber. Miinch. Akad., 1881. Cholera und deren Beziehungen zur parasitiren Lehre. Aerztl. Intellbl., 1881, No. iv—v. Der Boden und sein Zusammenhang mit der Gesundheit des Menschen. Berlin, 1882. Der Boden und sein Zusammenhang mit der Gesundheit des Menschen. Berlin, 1882, 32 pp. Also Ed. 2. Einleitung: Individuelle Hygiene. Handb. d. Hyg. Pettenkofer und Ziemssen. Leipz., 1882. Das Hygienische Institut der k. b. Ludwigs Max. Univ. Miinchen. Braunschw., 1882. Handb. d. Hyg., Leipz., 1882. Einleitung zum Handbuch der Hygiene und der Gewerbekrankheiten von Pettenkofer und Ziemssen. 1, No. I, Leipz., 1882. Zur Statistik der Kost-oder Halte-Kinder. Arch. f. Hyg., Miinchen & Berl., 1883, 1, 40. Beleuchtung des Kgl. Residenztheaters in Miinchen mit Gas und mit elektrischem Lichte. Arch. f. Hyg., Miinchen & Berl, 1883, 1, 384. Einwirkung der schwefelingen Sdure (SO.) in der Athemluft auf den thierischen Organ- {130} MAX VON PETTENKOFER 180. 181. 182. 186. 187. 188. 190. ismus. Sitzber. Miinch. Akad., 1883, xu, 449. Ueber die Cholera-Gefahr. Breslau. Aertzl. Ztschr., 1883, 157. Choleragefahr fiir Miinchen. Prag. Med. Webn- schr., 1883, vi, 289, 301. On the probability of an invasion of cholera in Europe. San. Rec., Lond., 1883, n.s. 4, v, 47-51. . Aetiologie des Abdominaltyphus. Arch. f. &ff. Gsndtspflg., Strassb., 1884, 1x, 92. . Ueber Desinfection der ostindischen Post als Schutzmittel gegen Einschleppung der Chol- era in Europa. Arch. f. Hyg., Miinchen & Berl., 1884, 11, 35. . Ueber Vergiftung mit Leuchtgas. Miinch. Sitzber. Minch. Akad., 1883, x111, 247. Ueber die Reinigung des Liebig-Denkmals in Miinchen (with Baeyer and Zimmermann). Berl. Chem. Ges., 1884, xv11, 230. Belehrung iiber das Wesen der Cholera und das Verhalten wihrend der Cholerazeit. (With R. Koch and Skrzeczka.) 1884. Die Entdeckung des Cholerapilzes. Miinch. Neueste Nachrichten, 1884. . Die Choleragefahr fiir Miinchen. Miinch. Neueste Nachrichten, 1884. Die Cholera. Nord. u. Siid., 1884; Deutsche Biicherei, 1884. Liz} MAX VON PETTENKOFER 191. 192. 193. 104. 195. 196. 197. 199. Cholera. Lancet, 1884, 11, 769, 816, 861, go4, 002, 1042, 1086. Pop. Science Montbly, 1884-5, xxvI1, 503; 621; 750; 1885, xXV1I, 25. El colera. Rev. Soc. Espan. de Hyg., Madrid, 1884, 11, 202. Die Cholera in Indien. Archiv d. Hyg., 1883, m1, 129. Aerzt. Int. Bl, Miinch. 1885, xxii, 223. Die Trinkwasser und die Choleraimmunitit des Forts William in Calcutta. Archiv f. Hyg., Miinchen & Berl., 1883, 111, 147. Trinkwasser und Typhus auf der Festung Marienburg im Jahr 1874. Jabresbh. d. Untersuch.-Stat. d. Hyg. Inst. d. k. Ludwig. Max. Unw., Miinch., 1883, 11-1v, 56-64. Cholera. Indian Med. Gaz., 1885, xx, 36. Ueber die Wasserversorgung der Stadt Linz a. Donau. Gesundheitsingenieur, 1886, No. i, Iv. . Ueber das Verhiltniss zwischen Bacteriologie und Epidemiologie. Miinch. Med. Wcbnschr., 1886, No. iv. Bemerkung (Zur Arbeit des Herrn. D. N. P. Simanowsky: Ueber die Gesundsheitsschid- lichkeit hefetriiber Biere und iiber den Ablauf der kiinstlichen Verdauung bei Bier- zusatz). Archi. f. Hyg., Miinchen & Berl., 1886, 1v, 24. {i32} MAX VON PETTENKOFER 200. 201. 202. 203. 204. 205. 206. Zum gegenwirtigen Stand der Cholera. Archiv. f. Hyg., Miinchen & Berl., 1886, 1v, 249, 397; 1886, v, 353; 1887, vi, 1, 129, 303, 373; 1887, vn, 1. “Chemische Sonette”” Als Manuscript gedruckt, Miinchen, 1886. Ueber Gesundheitsschidlichkeit mehrerer hy- gienisch und technisch wichtiger Gase und Dimpfe. Sitzber. Miinch. Akad., 1887, xvii, 179. Der hygienische Unterricht an Universititen und technischen Hochschulen. Vortrag in der . Eroffnungssitzung des vi. internat. Congresses fiir Hygiene und Demographie. September 1887 in Wien. Der epidemiologische Theil des Berichtes iiber die Thitigkeit der zur Erforschung der Cholera im Jahre 1883 nach Aegypten und Indien entstandten deutschen Commission. Miinchen und Leipz., 1888. Die Mittel zur schnellen und sicheren Entfer- nung alter, verhirteter und beschmutzer Oelfirnisse. Techn. Mittheil. f. Malerei von A. Keim, Miinchen, 1888, No. xl. Ist das Ausstromen grosser Mengen Kohlen- sture in Arbeitsriumen durch Defectwerden von Kohlensiure-KiihImaschinen geféhrlich? (With Emmerich), Ztschr. f. d. gesamte Bauwesen, 1888, No. vii. f133f MAX VON PETTENKOFER 207. 208. 200. 210. 212. 213. 214. 215. Die Typhusbewegung in Miinchen von 1851 bis 1887. Breslau. Aerztl. Ztschr., 1889, x1, 33. Wien. Med. BI. 1889, x1, 37; 51; 67; Giorn. internaz. d. sc. med., Napoli, 1889, n.s., x1, 280. Hofrath Dr. Max Jacubezky. Nekrolog. Miinch. Med. Webnschr., 1889. Miinchen eine gesunde Stadt. Miinch. Neueste Nachrichten, 1889. Rerum cognoscere causas. Ansprache des Prisidenten der k. b. Akademie der Wissen- schaften in der offentlichen Festsitzung am 15 Nov. 1890. Miinchen, 1890. . Ueber Wirkung der Gasbeleuchtung bei Chloro- formnarkose. Sitzber. Miinch. Akad., 1890, Xx, 1. Die Verunreinigung der Isar durch das Schwemmsystem von Miinchen. Miinchen, 1890. Zur Einfiihrung des Schwemmsystems in Miinchen. Miinch. Neueste Nachrichten, 1890. Ueber Verunreinigung und Selbstreinigung der Fliisse. Schilling’s Journ. f. Gasbeleuchtung u. Wasserversorgung, 18go. Verunreinigung der Isar durch Abflisse aus Miinchen und Verunreinigung des Isar- flusses bei niedrigstem Wasserstande. Miinch- f134} MAX VON PETTENKOFER 216. 217. 218. 219. 220. 221. 222. 223. ner Gemeindezeitung, Pt. 2, No. xcvii, 1890. Deutsche Bauzeitung, 1891, No. xiv. Die Untersuchung der Isar auf Flussverun- reinigung von Miinchen bis Ismaning und iiber die Selbstreinigung der Fliisse. Deutsche Bauzeitung, 1891, No. xix. Selbstreinigung der Fliisse. Deutsche Bau- zeitung, 1891, No. xxxv. Ueber Selbstreinigung der Fliisse. Vortrag gehalten in der hygienischen Section der 64. Versammlung deutscher Naturforscher und Aerzte zu Halle. Deutsch. Med. Webnschr., 1891, No. xIvii. Zur Schwemmkanalisation in Miinchen. Miinchen, 1891. Miinch. Med. Abbandl., No. xii. Zur Selbstreinigung der Fliisse. Archiv. f. Hyg., Miinchen & Berl., 1891, x11, 269. Zum gegenwirtigen Stand der Schwemmfrage in Miinchen. Miinch. Med. Wchnschr., 1891, No. xlv. Acht Thesen gegen die Miinchner Schwemm- kanalisation. Miinchen, 1892. Miinch Med. Abbandl., No. xxv. Ueber Cholera mit Beriicksichtigung der jiings- ten Choleraepidemie in Hamburg. Miinch. Med. Wcebnschr., 1892, xxx1x, 8o7, 826. Miinch. Med. Abbandl., No. xxxix. Med. Centralbl., Wien, 1892, xxvi11, 673, 683, 697, 135} MAX VON PETTENKOFER 224. 225. 226. 227. 228. 229. 230. 23%. 713. Wien Med. Bl. 1892, xv, 725. Sitzber. Aerztl. Verein, Miinch. 1893, 11, 107. Lancet, Lond., 1892, 11, 1182. Ueber die Cholera von 1892 in Hamburg und iiber Schutzmassregln. Arch. f. Hyg., Miinch. & Berl., 1893, xviir. Maasregeln gegen die Cholera hier, die sani- tiren Verhiltnisse der Irrenanstalten, Sie- chenhéuser, Arbeitshiuser, Gefangen- und Strafanstalten; Gutachten des k. Ober- medicinal-Ausschusses. Miinch. Med. Wch- schr., 1804, xL1, 181. Choleraexplosionen und Trinkwasser. Miinch. Med. Wcbnschr., 1894, xr1. Minch. Med. Abbandl., No. xviii. Canalisation von Ortschaften an Binnenseen. (With Bruno Hofer.) Miinchen, 1898. OtHER PUBLICATIONS BucuanaN, G. On Prof. Pettenkofer’s theory of the propagation of cholera. Med. Times ¢r Gaz., Lond., 1870, 1, 283. Bunt, Lupwic. Ein Beitrag zur Aetiologie des Typhus. Ztschr. f. Biol, Miinchen, 1863, 1, 1. CunnNiINGHAM, JAMES M. Recent experience of cholera in India. Lancet, Lond., 1874, 1, 477. CunNINGHAM, James M. Cholera: What Can the State Do to Prevent It? Calcutta, 1884. J136] MAX VON PETTENKOFER 232, 233. 234. 235. 236. 237. 238. 2390. 240. 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