PRACTICAL SINFECTION CIRCULAR ISSUED BY THE I ILLINOIS STATE BOARD OF HEALTH 19 0 6 SECOND REVISED EDITION SPRINGFIELD: Illinois State Journal Co., State Printers igo6 NOTE. The disinfection of infected premises is as important as the main- tenance of a quarantine during the prevalence of the disease. The virus of contagious and infectious diseases will often live for years. It is imperative, therefore, that the infected premises, with its con- tents, be thoroughly disinfected immediately after the death or re- covery of the patient, in order to avoid a spread of the disease. A disinfection performed in the manner recommended in this cir- cular, will be thoroughly eflPective. The work, however, must be properly done, as directed, else the disease may remain in the house, a menace to the health and lives of those who enter. The health officer should never forget the fearful consequences which may follow a neglect in any particular of this important duty. Disinfection should be performed by the city, village, township or county authority — (the latter in counties not under township or- ganization only — in territory outside of cities and villages) — under the immediate direction of or by a qualified health officer, or physi- cian or embalmer licensed by the State Board of Health. “ Whatever measures are adopted should be made thorough. “Measures, good or bad, half done are worse than useless, as they give a fancied security.” CONTENTS. PAtJES General considerations— Object of disinfection- . —What would be an ideal disinfectant -Disinfection of premises during illness I Aerial disinfection— Rules— Preparation of room and contents— Subsequent disinfection —Insecticides, formaldehyde and sulphur Sulphur disinfection— Rules— Plxperiments of State Board of Health— Disadvantages of sulphur— When sulphur is dependable 5-6 7-8 9-10 Formaldehyde disinfection— Methods— Experiments in past years w’ith lamps and gen- erators— Experiments of State Board of Health 1898-1902— Formaldehyde sprinlcled on blankets and sheets— “Sheet method”— Generators and autoclaves— “Candles”— Breslau method— Modification of Breslau method recommended under certain con- ditions— Best formaldehyde necessary— Much poor formaldehyde on market 11-14 P'1 Formaldehyde and potassium permanganate method of generating formaldehyde— The method recommended— Rules— Apparatus— Quantities of chemicals— Best quality of formaldehyde necessary; price— Account of experiments at ordinary temperatures— Penetrating power 15-21 Formaldehyde and potassium permanganate method— The method recommended— Re- sults at low temperatures— Previous experiments at temperatures below 60°— Ac- counts of experiments— Methods subjected to the severest tests— Freshly dried versus moist cultures— Penetrating powers- Effect on cultures in books— Quantities of chem- ,icals Final recommendations 22-26 27 27 Standard Disinfectants ‘PROVE ALL THINGS; HOLD FAST THAT WHICH IS GOOD.’* “BE SURE OF IT; GIVE ME THE OCULAR PROOF.” PRACTICAL DISINFECTION. With the Results of Experimental Work Done in the Laboratory of the Illinois State Board of Health, in Formalde- hyde Disinfection. General Considerations. The object of disinfection in the sick room is the destruction of infectious material attached to clothing, carpets, draperies, furniture or surfaces of the room, or deposited as dust upon the window ledges, in crevices, cracks, and other more or less inaccessible parts of the room. If the room has been properly cleaned and ventilated while still occupied by the sick person, and especially if it was stripped of carpets and unnecessary furniture at the onset of the attack, the difficulties of disinfection will be greatly reduced. The ’work of disinfection should begin wdth the beginning of the treatment and should continue during the whole course of the disease. All articles of bed clothing and of body clothing should be disinfected as soon as they are removed from the bed or from the patient. The liberal use of liquid disinfectants composed of chloride of lime, carbolic acid, or corrosive sublimate is strongly recommended in the sick room, but there should be no attempt to disinfect the room by any vapors or gases when occupied by the patient. This can not be accomplished. Fresh air, combined with absolute cleanliness, is the disinfectant most needed in the sick room. During the entire illness the privy should be thoroughly dis- infected with Standard 'Disinfectant No. 1, (see page 28) four or five gallons of which should be thrown into the vault every day. Instead of the solution, chloride of lime in powder can be used. All wood- work in the vault should be soaked with the solution or covered with powdered lime. Water closets and sinks should be disinfected daily by pouring a quart or more of the solution of chloride of lime or car- bolic acid into the pipes. The pipes should be freely flushed in order to avoid injury. As unsanitary surroundings and uncleanliness will tend to retard the recovery of the patient, every effort should be made to keep the house, cellar, outhouses and yard clean. The cellar should be freed of all rubbish and decaying matter and the walls whitewashed. All rubbish and decaying matter should be burned. Quicklime, Standard 6 Disinfectant No. 4, (see page 28) can be well used to whitewash ex- posed surfaces and to disinfect sinks, drains, decaying matter too wet to be burned, pools of water, etc. Attempts should be made to draw oflP all pools of water. In the disinfection of houses which have been occupied by those sufPering from contagious or dangerously communicable diseases, much can be accomplished by the liberal use of liquid disinfectants, by thoroughly washing all woodwork and exposed surfaces, and by the burning of mattresses and pillows, by the removal of wall paper after saturati®n with disinfectants, and by treating carpets, hangings and other fabrics and exposing them in the fresh air and to sunlight. The ideal disinfection would be one which would have no de- structive effect upon the contents of the room, which would have such penetrating power as to be effective upon all infectious materials how- ever inaccessible they might be and which could be applied with a minimum of labor. Such a disinfectant has never been found. Gases are decidedly limited as to penetrating power and are suited only for comparatively superficial disinfection. Liquid disinfectants are un- available for many uses. It is consequently essential that we adopt both the aerial and the liquid disinfectants, and that we give such at- tention to every detail that no article and no part of the room escape being subjected to the suitable disinfecting agent in the most advan- tageous way. “Disinfectants, or germicides, are agents which bring about the destruction of bacteria in general and, more particularly, of those that act as the excit- ing causes of disease. While they are all to be classed as antiseptics, the latter, as a class, are by no means necessarily disinfectants, since many of them act simply to delay or prevent the action of fermentative agents, with- out exerting any destructive influence upon them. Cold, for example, is a most efficient antiseptic; but while it may inhibit growth and activity of micro-organisms, it does not necessarily deprive them of vitality. ’’-Harrington. AERIAL DISINFECTION. The most effective part of house disinfection, however, is acorn- plished by the liberation of large quantities of disinfecting and germ- icidal gases, which impregnate the air, saturate the softer fabrics, and invade the most inaccessible and remote parts of the room. For this aerial disinfection the fumes of burning sulphur were formerly accepted by all health officers and sanitarians, but in more recent years formaldehyde gas has been used and exploited and has acquired a high degree of popularity. Whatever the agent used for aerial disinfection with fumes or gases the following certain general rules are essential to success, and may be laid down for adoption both by those who adhere to sulphur as the disinfecting agent and by those who prefer and use formaldehyde gas. Have all windows and doors (except doors of egress) tightly closed. Securely paste strips of paper over keyholes, over all cracks,, above, beneath and at sides of windows and doors, over stove holes,, and all openings in walls, ceilings and floor. If the opening be large,- paste several thicknesses of paper over it. Carefully stop up the^ fireplace, if there be one. There must be no opening through which; gas can escape. (b) All articles in the room that can not be washed should be' spread out on chairs or racks. Clothing, bed covers, etc., should be* spread on lines stretched across the room. Mattresses should be opened and set on edge. Window shades and curtains should be spread out at full length. If there is a trunk or chest in the room, open it, but let nothing stay in it. Open the pillows so that sulphur or formaldehyde fumes can reach the feathers. Do not pile articles, together. (c) After the aerial disinfection is completed and the room opened, take out all articles and place them in the sunshine. Carpets- should be well beaten and exposed to the sun. (d) All wood surfaces in the room should then be thoroughly washed with Standard Disinfectant No. 3. (see page 28.) Wash well all out of-the-way places, window ledges, mouldings, etc. Floors par- ticularly should receive careful attention and the solution should wet the dust and dirt in the cracks. If the walls are papered, soak the paper with the solution and have it removed. (e) After washing, ventilate the rooms, if possible for several hours, then scrub all woodwork with soap and hot water. (/) It is safer to burn mattresses and pillows. 8 {g) It is likewise safer to burn all books, toys and articles of little value which have been handled by the patient. Burn what you cannot boil or thoroughly wash. Books which have not been in the room with the patient may he saved. Lay them on edge of a table table with leaves open, in room while sulphur fumes or formaldehyde gases are being generated. It must be borne in mind that thoroughness of application is most essential, whatever method of disinfection may be adopted. Careless- ness in the slightest detail may be productive of the gravest danger to those whose confidence has been inspired by the assurances of safety. Although the patient suffering from contagious disease may have been confined to one room, it must not be forgotten that the avenues for the transmission of infective material to other parts of the house are never entirely shut off so long as there is any communication between the sickroom and other rooms. Even the sheet, saturated with liquid disinfectants, which experience has taught us to hang over the open door of the sickroom, may not serve as a barrier to all infectious material, especially if the nurse, the physician and mem- bers of the family pass frequently from the sickroom to other parts of the house. Hence, after cases of particularly contagious nature, not only the sickroom but all rooms contiguous to it should be thoroughly disinfected. Notes Concerning Insecticides. A few words here regarding the agents which can he depended upon to destroy vermin will certainly not be out of place. Some authorities have recommended formaldehyde as an insecticide. Those who have personally experimented with this agent know that it can not be depended upon to even kill mosquitoes in a room. Formaldehyde gas is but a feeble insecticide at best. It is never efficacious except when the gas is generated quickly and in large volume. Even then the results may be dis- appointing. Formaldehyde has ordinarily but little penetrating power. Usually the gas will not reach the folds of bedding and clothing, and out-of-the-way places in which vermin are prone to hide. As to sulphur, which is not only a reliable disinfectant, but also a power- ful and reliable insecticide, the following remarks of Surgeon M. J . Rosenau, Director Hygienic Laboratory, U. S. Public Health Service, will be inter- esting: “Sulphur dioxide is unexcelled as an insecticide. Very dilute atmos- pheres of the gas will quickly kill mosquitoes. It is quite as efficacious for this purpose when dry as when moist, whereas the dry gas has practically no power against bacteria. Contrary to formaldehyde it has surprising powers of penetration through clothing and fabrics, killing the mosquitoes, even when hidden under four layers of toweling, in one hour’s time — and with very dilute proportions. “This substance, which has so long been disparaged as a disinfectant be- cause it fails to kill spores, must now be considered as holding the first rank in disinfection against yellow fever, malaria, filariasis, and other insect-borne diseases.” 9 SULPHUR DISINFECTION. Disinfection by the burning of sulphur has been successfully practiced for many years. As stated by Surgeon General Sternberg, United States Army, “ the experience of sanitarians is in favor of its use in yellow fever, small-pox, scarlet fever, diphtheria and other diseases in which there is reason to believe that the infectious ma- terial does not contain spores.” This method of disinfection has also been endorsed recently by the United States Marine Hospital Service, after numerous experiments, during which the efficacy of sulphur dis- infection, in the presence of moisture, was conclusively proven. The results obtained by the Illinois State Board of Health, in the several experiments made, have been directly in line with those of other investigators. The burning of sulphur in the presence of mois- ture has been found an effectual method of gaseous disinfection, and one upon which entire dependence can be placed at all times in disin- fection after diseases due to micro-organisms not containing spores. After the preparation of the room, as described on page 7, reliable and cheap disinfection may be secured by the following method of the use of sulphur. (1) Use three pounds of powdered sulphur for every 1,000 cubic feet in the room. A room ten feet long, ten feet wide and ten feet high has 1,000 cubic feet. For a large closet use two pounds of sul- phur. (2) Burn the sulphur in an iron pot or deep pan. Let the pot or pan stand in a larger vessel containing water, which vessel should be placed on a table, not on the floor. For example, take a common wash tub, lay in it three or four bricks, pour in boiling water to the level of tops of bricks, put the pot or pan containing the required amount of sulphur on the bricks, place the wash tub and contents on a table. The disinfecting “apparatus” is then in working order. (8) Moisten the sulphur with alcohol and ignite. When the sulphur begins to burn, leave the room, close the door of egress, and carefully paste strips of paper over the keyhole and all openings above, beneath and at sides of door. Keep the room closed for ten hours at least, twenty-four if possible. Sulphur candles may be used instead of crude sulphur, but care must be taken to use sufficient candles. The average candle on the market contains one pound of sulphur. Three of these will be re- quired in the disinfection of a small room 10x10x10. Do not use a less number, no matter what directions may accompany the candle. The water- jacketed candle is preferable. Partly fill tin around candle with water and place candles in a pan on the table, not on the floor. 10 Let at least one-half pint of water be evaporated with each candle. Evaporate more if practicable. In the absence of moistnre, the fumes of sulphur have no disinfecting power. . There is, however, one serious objection to the use of sulphur, and this must be fully understood. The fumes of sulphur (sulphur- ous acid) have a destructive action on the fabrics of wool, silk, cotton and linen, on tapestries and draperies, and exercise an injurious influ- ence on brass, copper, steel and gilt work. Colored fabrics are fre- quently changed in appearance and the strength impaired. Fabrics, however, can be effectually disinfected by hanging them on a line ex- posed to the sun and wind for several days. Curtains and all articles of cotton or linen, boiling or soaking them in Standard Disinfectant No. B, for several hours, and portable articles of brass, copper, steel and gilt work by washing with a strong solution of carbolic acid (Standard Disinfectant No. 1). Colored fabrics which have been in a room during disinfection should be immediately exposed to the sun and wind. Uncolored fabrics which will not be injured by moisture should be at once soaked in water. This action will prevent further injurious action of the sulphuric acid. Sulphur will be found a thoroughly reliable gaseous disinfectant of considerable penetrating power, if it is intelligently employed. To obtain satisfactory results, the following essentials of successful dis- infection, established by repeated experiments, must be observed: (a) The infected room, or rooms, must be thoroughly closed, every crack and crevice sealed. (6) Sufficient sulphur must be used, (c) There must be moisture in the room, {d) The time of exposure must be sufficient, ten hours the minimum. In the disinfection of stores, halls, school houses and apartments or dwellings, in which there are no articles to be injuriously affected by the gas, sulphur is an ideal disinfectant. Its mode of application is simple (the simpler the mode of application the better), it is cheap, the material is accessible everywhere, and, finally, the most important of all, the action will be invariably found effective when the sulphur is properly used. “Cleanliness is an important adjunct to the work of disinfection. *•»•***** “Cleanliness accomplishes another important purpose as far as infection is concerned; it removes the organic matter on which and in which the bac- teria find favorable conditions for prolonging life and virulence.” — Rosenau^ 11 FOKMALDEHYDE DISINFECTION,^ On account of the destructive properties of sulphur, efforts have been made to find a satisfactory substitute for this agent, one of equal germicidal power, which will not damage the contents of the room. If dependence could be placed on the published results of in- numerable experiments made with formaldehyde, there would be no necessity for further search for the much desired substitute. For- maldehyde has been lauded as the most powerful sterilizer and germi- cide known; as a gaseous disinfectant far superior in efficiency to sulphur — one seemingly without limitations, effective at all times. The results obtained by careful observers in experiments made, not in laboratories, but in dwelling houses, shops and railroad cars, in which disease is often found, do not substantiate the extravagant claims made for formaldehyde. Formaldehyde (otherwise known as methyl aldehyde, formicalde- hyde and “ formalin ”) exists in several forms, but is principally known as a gas. Its germicidal properties were not recognized until 1886. and were not put to use until 1890. The formaldedyde gas is the vapor of wood alcohol which has undergone a chemical change. The gas is produced by passing the vapor of wood alcohol over plati- num or platinized carbon in an incandescent state. Many portable apparatus for the production of formaldehyde gas directly from wood alcohol have been devised during the past ten years. The writer made a series of experiments in 1896-7, while connected with the Chi- cago Health Department, with the lamps then on the market. The tests were conducted in the most painstaking and careful manner, but in every instance the results were unsatisfactory. It was found that the lamps did not give off sufficient formaldehyde; that the alcohol was generated too slowly, and that large quantities of alcohol passed through the lamp unchanged. But few bacteria were killed by the gas evolved. There was consequently no disinfection. Not one of these lamps so highly endorsed in 1896 as ideal apparatus for the production of formaldehyde gas is now offered for sale. Experiments were made at the same time under the best possible conditions with the generator in which the fluid formaldehyde was boiled and vapor- ized. Disinfection failed in nearly all these experiments. In 1898 the State Board of Health commenced experiments for the purpose of confirming or disproving the many claims made for formaldehyde by sanitary authorities at home and abroad, and inci- dentally for the purpose of finding a practical method of disinfection with this agent. These experiments were made under the direction ♦ See page 15 for method recommended. 12 of Professor T. J. Burrill, of the University of Illinois, and were con- tinued at intervals until 1902. The results of the experiments are as indicated below. The aqueous solution of formaldehyde gas, known as formalde- hyde and ‘Tormalin,” is a 40 per cent solution of the gas formaldehyde in water. It is claimed that many of the commercial preparations do not contain 40 per cent of formaldehyde. Several processes have been devised for the liberation of formaldehyde gas from its watery solu- tion. The solution when exposed to the air gives off a considerable quantity of the gas, especially when sprayed on large surfaces. If the solution be sprayed on blankets or sheets or articles of clothing hung in the room or on the walls, the liberation of the gas will be so rapid as to compel the operator to leave the room. These facts have given rise to the belief that exposure of the gas in this manner will be sufficient to cause disinfection. The results, however, do not con- firm this. There is much uncertainty as to the amount of gas which is evolved, and the behavior of the gas is at times capricious. It has been determined by the United States Public Health Service after a series of extended experiments conducted by Past Assistant Surgeon M. J. Rosenau, that formaldehyde sprinkled on blankets and sheets has practically no disinfecting power in a closed box, excepting on the spot where the solution falls; this after a twenty-four exposure. The amount of gas given off from the aqueous solution of formal- dehyde at ordinary temperatures is exceedingly small. After the solution has been applied to exposed surfaces, the liquid becomes concentrated, and as found years ago by Surgeon J. J. Kinyoun of the United States Public Health Service, the greater proportion of the formaldehyde gas is converted' into a yellowish white amorphous substance known as trioxy-methelene. In this state it gives off but a slight amount of formaldehyde. The State Board of Health conducted a number of exper- iments during the years 1899-1902 to test the efficiency of the so- called “sheet method” of disinfection, which consists of suspending sheets in the infected room, and spraying them with a solution of formaldehyde, using about six ounces of the forty per cent, solution to each thousand cubic feet of air space. The results with this method have not be.en satisfactory. At times under favorable conditions the method proved effective, while again under almost identical condi- tions, it was found worthless, even when the amounts of formaldehyde on the areas of sheet surface were increased. At temperatures below 60*’ F. the results were invariably unsatisfactory. To ensure good results with this method it is absolutely neces- sary that the sheets be sprayed evenly in small drops over the entire surface, care being taken not to go over the same surface twice. Even the most enthusiastic advocates of the “sheet method” admit that the results will be unfavorable unless this precaution be observed. For- maldehvde is exceedingly irritating to the respiratory passages and to the eyes, so that it becomes a test of human endurance to remain in a room for the time necessary to properly spread sufficient solution to 18 disinfect a very small space, while in a room of ordinary dimensions, which would require a number of sheets, the proper spreading of the solution by one man becomes a matter of absolute impossibility.* The ordinary disinfector working under conditions so decidedly unpleasant will, in the majority of instances, slight his work, so that even if the sheet method were much more efficient than it is, the re- sults of its practical application would seldom be satisfactory. These conclusions have been reached by diflPerent State Boards of Health throughout the country, which have made personal inves- tigations into the efficacy of this mode of disinfection. Rosenau. of the United States Public Health Service, says, that the “sheet method” has distinct limitations and unless all necessary conditions are carefully observed, is very untrustworthy. The gas is given off very slowly and in very uncertain quantity, diffuses poorly in dead spaces and is entirely inapplicable to large enclosures. Even when conducted with the utmost care, the method is limited to rooms not exceeding 2.0CO cubic feet. In view of the fact that it is practically impossible for a disinfector to properly spray the sheets, over a sufficient area to have effect in rooms of more than small dimensions; in view of the fact that there will be no disinfection unless the sheets be properly sprayed; in view of the fact that the method is utterly worthless at even reasonably low temperatures, and further in view of the unreliability of the method, indicated in the numerous failures to kill bacteria, even of feeble resisting powers, when technique seemed perfect and condi- tions favorable, the Illinois State Board of Health can not recommend its use to physicians or health authorities. “An effective method of disinfection must have no exceptions; it must invariably kill.” The most common method of obtaining formaldehyde gas from the watery solution at the present time is by means of apparatus designed to regenerate the gas by boiling the solution under pressure. Many generators operating on this principle are to be found on the market. Several of these are complicated machines requiring skill to properly operate. As some of the generators require constant attention, it has been found necessary to place them outside of the apartment being disinfected and to pass the gas into the room by means of a tube run through a keyhole. The diffusion of the gas produced in this way is slow, particularly in large areas, tending to its concentration at a few points and to the formation of paraform. This method of disinfection cannot be recommended. To insure a perfect disinfection with for- maldehyde it is necessary that the gas be liberated quickly and in large volume. Formaldehyde “candles” composed of paraform are now offered to health authorities as a means of disinfection. No dependence what- ever should be placed on these candles. * Laboratory Investigations. * * * Spraying- a sheet with formal" dehyde while the operator is standing in front of the sheet is a procedure claimed to be possible only by those who have never tried it, and describe it from imagination. * After ten ounces had been sprayed further operation was rendered impossible by the unbearable, irritating vapor of the formalde- hyde; ^ ^ Disinfection not obtained in experiments conducted; — Bulletin of the Pathological and Bacteriological Laboratory of the Delaware State Board of Health. 14 The evaporation of the solution of formaldehyde by the means of heat in an ordinary kettle is one of the simplest methods of disinfec- tion with formaldehyde, and the results have proven effective. This method was endorsed by the writer in 1896. This is termed the Breslau method. Many health authorities have testified to its efficiency during the past eight years. To quote from the monthly report of the Chicago Health Department of January, 1898, in which this pro- cess is described at length and heartily endorsed: “A six hours’ exposure under these conditions has given better results in the steril- ization of cultures than has been obtained by any other method, and the other requirements — of simplicity and portability of apparatus, rapid evolution of the disinfecting agent and brief duration of expos- ure, together with reasonable cost of disinfection — are very nearly met.” A very simple apparatus for disinfection by this method was de- vised by the Health Department of St. Louis in 1898. This consists of a copper kettle for the disinfectant, a tripod, and a copper vessel containing mineral wood for the alcohol. When the apparatus is placed in order the kettle is partly filled with hot water and the alco- hol in the vessel beneath is ignited. As soon as the water boils there is poured into the kettle a quantity of the 40 per cent solution of for- maldehyde, forty ounces being sufficient for the disinfection of 2,000 cubic feet of air space. In order to produce sufficient moisture, there is used in addition a similar apparatus in which water alone is boiled. The State Board of Health conducted many experiments with this apparatus, and the results have been generally satisfactory, and it is evident that the apparatus, when properly used, can, under favorable conditions, be relied upon to produce a proper amount of formalde- hyde gas of the highest efficiency. After repeated tests made at in- tervals from 1899 to 1901, the Board feels justified in endorsing this method of disinfection with formaldehyde, with a proper apparatus. To obtain proper results with this or any other apparatus it is ab- solutely necessary that the best formaldehyde or formalin be obtained Much of the formaldehyde sold in the United States under different names cannot be relied upon. To be effective formaldehyde must contain not less than 38 per cent of strength. There is also much difference in the quality of wood alcohol found on the market. Alco- hol 95 per cent proof must be used in this apparatus. The best imported formaldehyde (formalin) was used in all the experiments conducted by the Illinois State Board of Health. In disinfection with formaldehyde the same precautions relative to the sealing of the room should be taken as in disinfection with sulphur. It must be borne in mind also that the gas of formaldehyde, unlike like that of sulphur, has but feeble penetrating power. There is no doubt, however, that the gas of formaldehyde will penetrate wherever infection has been carried by the surrounding atmosphere. 15 THE FOKMALDEHYDE AND POTASSIUM PERMANOA- NATE METHOD OF GENERATING FORMALDEHYDE GAS. The Method Recommended. * While the results obtained with some of the methods of formalde- hyde disinfection formerly suggested have been generally satisfactory, failures were at times experienced when the conditions were ap- parently ideal, while under unfavorable conditions of temperature and humidity, ineffective disinfection was of frequent occurrence. For this reason, while placing before the physicians and health officers of the state the best methods of formaldehyde disinfection, the State Board of Health has continued to advocate sulphur for aerial disin- fection as the only agency which had demonstrated beyond question its efficiency and reliability at all times. Aside from the uncertainty of results of the methods of formalde- hyde disinfection offered for use, the apparatus has often been com- plicated in operation, unnecessarily expensive and dangerous as to destruction of property by fire. An exceedingly simple method of generating the gas by pouring formaldehyde solution over the crystals of potassium permanganate in an open vessel, has been more recently suggested and gave promise of overcoming the objections which have stood in the way of the more general adoption of formaldehyde as a disinfecting agent. This method primarily offered the advantages of absolute simplicity in operation, requiring no special apparatus and no fire. In addition to this, exhaustive experimental work has demonstrated that, in practical disinfection, the method is unusually efficient, the effectiveness seem- ing to depend less upon the conditions of humidity and temperature than that of any other method. The only apparatus required is a large open vessel, protected by some non-conductive material to preserve the heat within. An ordi- nary milk pail, set into a pulp or wooden bucket will answer every purpose, although a special container, devised for physicians and health officers, will be found of considerable advantage. This con- tainer or generator consists of a simply constructed tin can with broad flaring top. Its full height is 15J inches, the height of the flaring or funnel-shaped top being about 8 inches. The lower or round section is 10 inches in diameter, while the funnel top is 17J inches in diameter at the top. This container is made of a good quality of tin, is supplied with a double bottom with a layer of as- bestos between the layers of tin, and is entirely covered on the out- 16 DISINFECTING APPARATUS. (Designed by the Maine State Board of Health.) Heig’ht, 15)^ inches; heig-ht of lower portion, 8 inches; diameter at top, 173^ inches; diameter at base, 10 inches. Made of bright tin and covered with asbestos paper. 17 side with asbestos paper. The asbestos paper and double bottom serve to effectively retain the heat which is generated by the vigorous chemical reaction occurring within the generator, and which is es- sential to the complete production and liberation of the gas. The special retainer can be made by any tinner of ordinary intelligence, and costs but a few dollars. This method of aerial disinfection was first suggested in 1902-3, but it was given no publicity until 1904, when it was described by Dr. G. A. Johnson, of Sioux City, Iowa, in a paper read before the Sioux Valley Medical Association. Even then it attracted very little attention and was not subjected to systematic tests until late in 1904. when numerous experiments were made by the Maine State Board of Health. The test-bacteria used in the experiments of the Maine board were diphtheria, typhoid, staphylococcus albus and aureus, coli communis, pyocyaneus, tetragenus, streptococci, anthrax, subtilis, and mixed cultures mostly from swabs from the throats of patients thought to have diphtheria. The time of exposure was at first 16 hours, but this was gradually reduced to 3 hours with no lessening efficiency. Of the 1,529 test objects exposed in 279 experiments, only twenty- seven showed a growth after incubation for at least 48 hours. Of these twenty-seven unsuccessful results, twenty-one were with the exceedingly resistant hay bacillus (B. subtilis). None of the bacilli of diphtheria, typhoid fever or other ordinary pathogenic germs sur- vived the exposure to formaldehyde. While placing great dependence on the results obtained by the Maine State Board of Health, the Illinois State Board of Health decided to pursue the policy adhered to since 1898, to make a sys- tematic test of all methods of disinfection recommended before en- dorsing or condemning the methods. During the summer and autumn of 1905 exhaustive experimental investigations were carried on with this method of disinfection in the laboratories of the State Board of Health at Springfield. An ordin- ary office room, containing 1,080 cubic feet of air space, was secured, situated conveniently to the laboratory. The door was carefully sealed with strips of gummed paper and access to the room was gained through an outer window. This window, was not protected by paper strips, but set closely in its frame. Twenty-four (24) hour bouillon cultures of various forms of bacteria were prepared. Strips of milk paper in. x 2 in. ) were saturated with these cultures. The slips were saturated in pairs, one slip being exposed to the fumes of the gas in the room, the other placed in a sterile envelope, sealed, labeled and kept in the laboratory to be used as a control. After the exposure of the first slip to the fumes of the gas generated by pouring the 40% formaldehyde solution over the permanganate of potassium in the usual manner, it was returned to the laboratory, both slips placed each in a tube of sterile bouillon, incubated at 37° C. for 48 hours, and later examined and compared. On account of the variable results obtained by other methods of formaldehyde disinfection, depending largely upon the temperature 18 and atmospheric conditions, days were selected for experimental work which varied greatly in temperature, humidity, cloudiness and other climatic conditions, and these conditions were made a part of the laboratory records. Specimens were exposed for a period of 6 hours and, between ex- periments, the room was left open that it might be entirely freed of any traces of formaldehyde gas. The results of experiments of the Illinois State Board of Health are shown in the tables on pages 19 and 20. It will be noted in the tables of laboratory tests that the bacterial growth was entirely destroyed when one quart (32 oz.) of formalde- hyde was used to the 1,000 cubic feet of air space, and that equally satisfactory results were obtained with one pint (16 oz.) of formalde- hyde. It may consequently be stated that, under ordinary conditions of house disinfection, the room being well sealed, a pint (16 oz.) of formaldehyde solution with 6f oz. of potassium permanganate will be ample for 1,000 cubic feet of air space. With these amounts bacterial cultures, enclosed in from one to four layers of 4^ oz. flannel, were destroyed, these cultures including the bacillus subtilis (hay bacillus) known to be especially resistant to formaldehyde gas. It is not yet determined how small quantities of formaldehyde and permanganate of potassium will produce satisfactory results, but it is the part of wisdom not to economize in materials if there is the slightest danger of reducing the germicidal power. Even with the largest quantities named, a quart of formaldehyde to 13^ oz. of potassium permangan- ate, the cost is small. It might be noted in this connection that the Maine State Board of Health adopted in its experiments the proportion of 6^ oz. of potassium permanganate to 32 oz. of formaldehyde for each 1,000 cubic feet of air space, and in a recent circular still recommends these amounts. However, as stated above, it has been the experience of the Illinois State Board of Health that under proper conditions, (at temperatures above 60° F.) one pint (16 oz.) of formaldehyde (the 40^0 solution ) with 6| oz. of potassium permanganate will be sufficient for the disinfection of 1,000 cubic feet of room space. The results obtained with this method, in experiments conducted by the Illinois State Board of Health, under varying atmospheric conditions and with a rather wide range of temperature, indicate that there has been Anally found a method of formaldehyde disin- fection which will prove effective under reasonable conditions, at temperatures ordinarily found in the living or sleeping rooms, while the simplicity, the small expense of apparatus (in fact, its successful operation without apparatus of any kind, if necessary) and the moderate cost of operation, serve to commend it. In the work of the State Board of Health the best quality of imported formaldehyde (formalin) was employed, and Merck’s potassium permanganate, but even with the highest grade of ma- terials the cost is small. It must be borne in mind that the quantities of potassium perman- ganate and formaldehyde set forth above, should be used only Forinaldehijde — Potassium Permanganate Method. 19 Ti w OS P- 3 W X Bacillus Subtilis. .. bi) be O) be 01 be 01 4) 01 Z Oi 4J 01 'Z Z Z Z Z z Z Z z Z Z Bacillus be be be be bi) be be bi) be be bi) be bi) be be Tvphosus V V Z 0) Z 0) 0) OI 01 4) 01 0) o< V 01 V Z Z Z Z Z Z z Z z Z Z Z z Bacillus Coli be bi) bi) bi) be be be bi) be bi) bi) bi) bi) bi) be Communis V 4; a; o> V 0) 0) 01 01 4 ; 01 01 Z 01 01 Z 4) Z Z z Z Z Z Z Z Z Z Z Z z * Mean 'I'empera- •^C- 1 CO t-* 1 t^CO < ir-CO 1 1 1 ir't'i t— 1 t— tr- 1 0000 « OS os OS OS OS OS OS os OS OS os os os os' Formaldehyde per 1,000 cubic c < < D <» L) lU J o M 01 o u in V u cn 01 u cd 0) 0 in 01 0 GQ V U feet G- G G G G G G G G G a G G G G 3 3 G G G G G G G G G G G G G 1 0 o O O O O O O O 0 0 0 0 0 0 S3 M CM w CM (M w OJ S3 w Ol S3 N CM ec CO oo CO eo oo 00 00 00 00 CO i OT3i3 .3 . G O a 2 >> I >, I >>o X^'OO'Oo'Go ,G -G .G . a o GO a o c I >> I 0 730 .G . GOG . 2 '^.2 > 1.2 o . 2 o 2 ^ 2 k ^ 2 k ^ 2^-2 ’ rt ■? G ^ rt "2 rt "2 G 2:? G G >..2 'O'G lJ G^rzJ-G rt+3 32 ca 0-G2'G Oi-G OG 0) a2 aGi a5 aGi aGi aGi aGi a2 a3 *o O ‘G Ph ’o O *G Oh *u *o ^ *u CJ ’o O Ij &-J *G O ‘5 U ’G O ‘G O *o U 'u CU a>o>a>a>a;a;a;a) XQhOhOhC-iD-iOmCLiCLiPhCLiCI^OhOmCGi Number of experiment. M ?0 Temperature indicated by “ R ” is the temperature of the room. Temperature first given is out of door temperature. Neg.— No growth. RESULTS OF EXPERIMENTS AT ORDINARY TEMPER AT U RES- 20 Bacillus Subtilis... be 0) be (V Z bi) bi) bi) O) be 03 Z be 03 bi) 03 bi) 03 bi) 03 be 03 be 03 z bi) 03 bi) 03 hi) 03 bo be 03 03 z Z Z Z z z Z Z z Z z z Bacillus Coli Communis be bi) be 03 03 Z z Z z Z z Z Z Z z z z * Mean Tempera- ture tiH pL| b ^ b ;2 h {±4 h ^ b b t-»rtC-00OkrteC3 ZZZZZ .•bctictjsticbcbctxbchtbc :ZZZZZZZZZZ Bacillus coli communis, Bacillus typhosus , Bacillus subtilis. Bacillus anthracis. Formaldehyde, per 1,000 cubic feet Precipitation in inches. Vapor pressure. Relative humidity. o . o >> Mean temperature day outdoors Temperature of room- ending Temperature of room- beginning Number of experiment. ; iy; tx be he be be be be.2 he . (U K (U 0) oj CO 05 t- 00 CO 1— K00-^'^C~'^00055 -iOCOOOC ^ . o Oz o :Z £2? Oz Bacillus coli communis he he x2 ; he 4) i) — . 41 ZZ o :z 5^ £ Oz O :z he ho 4> 4> ZZ Bacillus typhosus . he he x2 I he 4) 4; M> . 4) ZZ o ;z ZZ O Bacillus subtilis. 42 he x2 1 he .M 4> . o Oz O :Z 42 ho x: