UC-NRLF *B Ifl IflM II i $ 1: 1 i It I Ij in II 1 m 1 1 I i f f I 1 1 i 5 ¥ ! I I I M HHH I WmMi iS^^,,^-. «r; ■* > .... ..V: ' -*■ »^" 4ft Digitized by the Internet Archive in 2007 with funding from Microsoft Corporation http://www.archive.org/details/disinfectiondisiOOamerrich y C^C^i- — w , //?6 DISINFECTION AND DISINFECTANTS: THEIR APPLICATION AND USE Prevention and Treatment of Disease, Public and Private Sanitation COMMITTEE ON DISINFECTANTS, APPOINTED BY THE AMERICAN PUBLIC HEALTH ASSOCIATION, If Cotuor.b, ft. J|. Republican Press Association, 22 North Main Street. 1888. UBRART PUBLIC HEALTH LIBRARY Copyright, 1888. By Irving A. Watson, Secretary American Public Health Association. t t rr rr r r f NOTE. This volume is the result of the labors of the Committee on Disin- fectants, appointed by the American Public Health Association in October, 18S4. The committee continued its researches, investigations, and experiments for three years, and made its final report in November, 18S7. Only by a careful study of this volume itself will the amount of work this committee performed, and its great value to the interests of health, be appreciated. The ability of the committee, composed of men all eminent in their professions, is a sufficient guaranty of the high charac- ter of this work. The original experimental investigations made by the committee are of the greatest importance and value, and render this the most complete and practical volume upon disinfection and disinfectants yet published. This work was presented in three annual parts : hence the entire dis- cussion of a given subject may not always be found in one place. A copious index has been prepared, by which all the matter pertaining to a specific topic may readily be found. I. A. W. 418011 REPORT OF THE COMMITTEE ON DISINFECTANTS. 1885. COMIMIITTEE. GEORGE M. STERNBERG, M. D., Surgeon U. S. A. ; Fellow by Courtesy in Johns Hopkins University. JOSEPH H. RAYMOND, M. D., Commissioner of Health of the city of Brooklyn, N. Y. CHARLES SMART, If. D., Surgeon U. S. A. ; Member National Board of Health. VICTOR C. VAUGHAN, M. D., Ph.D., Member Michigan State Board of Health. A. R. LEEDS, M. D., Member New Jersey State Board of Health. W. H. W ATKINS, M. D., Medical Director of the Auxiliary Sanitary Association of New Orleans. GEORGE H. ROHE, M. D., Baltimore. INTRODUCTORY. GENERAL REPORT OF THE SECRETARY. At the last annual meeting of the American Public Health Association, held in St. Louis, Mo., October 14-17, 1S84, the following resolution was offered by Dr. James F. Hibberd, of Indiana, referred to the Execu- tive Committee, and, after a favorable report by that committee, unani- mously adopted by the Association : Whereas, It is important, equally for practitioners of medicine, for boards of health, and for the general public, that the highest attainments of science in this department of sanitation should be formulated for easy reference by all who need it for practical appli- cation, and especially is this desirable in view of the probable visitation of cholera in the near future; — therefore be it Resolved, by the American Public Health Association, That a committee be appointed to examine the subject of disinfectants, antiseptics, and germicides, in their relations to preventive medicine and sanitation, and that said committee formulate a table of these agents for the information of those interested, the agents to be classified, so far as may be deemed advisable, according to their specific virtues, facility of application, and economy of use. In accordance with this resolution, the following committee was appointed by the president of the association : Major George M. Sternberg, Surgeon U. S. Army, Fellow by Courtesy in the Johns Hopkins University, Baltimore ; Dr. Joseph H. Raymond, Professor of Physiology and Sanitary Science in Long Island College Hospital, and health commissioner of the city of Brooklyn ; Dr. Victor C. Vaughan, Professor of Physiological Chemistry in the University of Michigan, and member of the Michigan State Board of Health ; Major Charles Smart, Surgeon U. S. army, and member of the National Board of Health ; Dr. W. H. Watkins, Medical Director of the Auxiliary San- itary Association of New Orleans ; Dr. Albert R. Leeds, Professor of Chemistry in Stevens Institute of Technology, and member of the New Jersey State Board of Health ; and Dr. George H. Rohe, Professor of Hygiene in the College of Physicians and Surgeons, Baltimore. The committee met immediately after appointment, and organized by the election of Dr. Sternberg as chairman and Dr. Rohe as secretary. In order to be enabled to make an extended experimental research, the committee, after consultation, decided to appeal to municipal and state boards of health, and to other sanitary organizations, for financial aid. Responses to this appeal were encouraging ; and a statement of receipts and disbursements on account of this work is appended to this report. At a meeting held in Baltimore on November 20, 1884, the committee 6 *\\ \ Z&potiT; o£[ q&wmzTEE on disinfectants. was divided into two sub-committees, — one, consisting of Drs. Sternberg, Smart, and Roh£, to examine the literature of disinfectants, and abstract and tabulate the results, and to investigate in an exact manner in the lab- oratory the relative germicidal value of the various substances used as disinfectants. The latter part of the inquiry was exclusively under the direction of Dr. Sternberg, the chairman of the committee, who was granted exceptional facilities for carrying on this work in the biological laboratory of the Johns Hopkins University. The committee would here take occasion to express to the trustees of the university its high apprecia- tion of the courtesy and aid extended by them while these investigations were in progress. The second sub-committee, consisting of Professors Raymond, Vaughan, and Leeds, and Dr. Watkins, was appointed especially to investigate the practical application of such disinfectants as are found efficient, upon a large scale, their cost, methods of use, chemical relations, effects upon furniture or fabrics, or their possibly poisonous effects upon human be- ings or animals. Reports and papers from members of both of these committees will be found under the heading " Experimental Data" in the body of this report. The therapeutic value of the various substances investigated does not properly come within the purview of the committee, and has conse- quently received no attention. At the conference of state boards of health, which was held in Wash- ington, December n and 12, 1884, a preliminary statement of the work then accomplished and contemplated was made ; and in accordance with authority received from the executive committee of the American Public Health Association, a series of preliminary reports has been published during the present year, in a medical journal of wide circulation — the Medical JVews, of Philadelphia. To Messrs. Lea Bros. & Go., the publishers of the journal mentioned, the committee is indebted for sub- stantial aid afforded in rendering the results of the committee's work promptly available to sanitarians and the public. The compensation received for the papers published in the .Medical News was kept as a separate fund to cover the cost of printing the report herewith submitted. A considerable deficiency has resulted, responsi- bility for which has been assumed by individual members of the com- mittee. George H. Rohe, Secretary. FINANCIAL STATEMENT. RECEIPTS. From American Public Health Association, $50.00 " H. Lomb, Esq., 50.00 " W. G. Little, Esq., 50.00 " Connecticut State Board of Health, 50.00 " Illinois " " 50.00 " Iowa " " 50.00 " Louisiana " " 25.00 " Massachusetts " " 50.00 REPORT OF COMMITTEE ON DISINFECTANTS. From Michigan State Board of Health, $50.00 " New York " 50.00 South Carolina Wisconsin 25.00 25.00 " Provincial Board of Health, Canada, 25.00 " Boston " " 25.00 " Brooklyn " " 100.00 " Charleston " " 25.00 " Pittsburgh " u 25.00 " Sanitary Protection Association, Newport, R. I. 10.00 " Members of the committee 12.15 Total, $747-15 EXPENDITURES. Laboratory expenses, $264.18 Salary of assistants, 400.00 Printing, binding, and mailing Preliminary Report, stationery, postage, express charges, and incidental expenses, 82.97 Total • $747-15 PRELIMINARY REMARKS BY THE CHAIRMAN OF THE COMMITTEE. A complete investigation of both disinfectants and antiseptics being impracticable in the time and with the resources at command, the com- mittee decided upon so far departing from the letter of the resolution under which it was appointed as to limit its investigations to the subject of disinfectants, properly so called, that is, to those agents which are capable of destroying the infecting power of infectious material. In the experimental investigations made by the writer in the biological laboratory of Johns Hopkins University, the biological test of disinfecting power has been the only one employed. In applying this test a variety of micro-organisms have been subjected to the action of the various agents under trial, and the object in view has been to determine, within suffi- ciently narrow limits for practical purposes, the percentage in which these agents are capable of destroying the vitality of the test-organisms in a given time. This is determined by a series of experiments in which the agent being tested is used in a greater or less amount, according as it is found to fail, or to be effective. Failure is shown by the fact that the test-organisms grow in a suitable culture medium after having been exposed to the action of the disinfectant ; on the other hand, failure to multiply in such a solution is evidence that the test-organisms have been killed. Further details with reference to the method will be found in the paper on k ' Commercial Disinfectants," and also in my paper published in the A?nerican Journal of Medical Science, April, 1883, in which I give the results of an extended series of experiments of a similar nature. Experiments of this kind require a certain amount of technical skill, and a very great expenditure of time. Results which are recorded in a $ REPORT OF COMMITTEE ON DISINFECTANTS. single paragraph have often been reached only after making numerous experiments extending through days or even weeks. It would of course be desirable to test each disinfecting agent upon a variety of pathogenic organisms ; and there is no doubt that, within cer- tain limits, differences in resisting power would be found. But this would be a task involving a still greater expenditure of time and money, and one which should follow the more general study which we have made. The work already done is sufficient to justify the general statement, that in the absence of spores, an agent which destroys the vitality of one micro-organism of the class to which known disease germs belong will destroy all other organisms of the same class, although not neces- sarily in the same amount, or in the same time. The fact that a certain agent destroys micrococci and bacilli without spores cannot, however, be taken as evidence that the same agent will destroy spores, for these reproductive bodies have a far greater resisting power; and certain chemical agents — e. g., carbolic acid, sulphur diox- ide — which are germicides, in comparatively small amounts, so far as micro-organisms in active growth are concerned, are quite impotent for the destruction of spores. It has not been possible to make an exhaustive study of disinfectants, and the agents selected for experimental work have been chosen from a practical point of view, the object having been to fix as nearly as possi- ble the value of those agents most relied upon by sanitarians for disinfect- ing purposes, and the conditions of successful disinfection with them. George M. Sternberg, Chairman. EXPERIMENTAL DATA. COMMERCIAL DISINFECTANTS. NO. I. BY GEORGE M. STERNBERG. In conducting the experimental investigations of the committee on dis- infectants, the writer determined at the outset, in the interest of health officials and of the public, to ascertain the comparative values of the vari- ous commercial disinfectants in the market. In a recent paper by Wynter Blyth, medical officer of health for Marylebone, in which the commer- cial disinfectants, exhibited at the London Health Exhibition, are intelli- gently discussed, we find the following : Rampant rides the quack in the fields both of preventive and remedial art. Quack- ery takes a well known common powder, labels it with a grand mystic name, selling bright copper at the price of gold. Quackery finds a stink outstinking feebler stinks, and gives it forth as a disinfectant. Of all the substances gathered together under the name of dis- infectants — solids, vapors, gases, and odors — a small percentage alone possess any value. 1 *Med. Times and Gaz., London, Oct. n, 1884. REPORT OF COMMITTEE ON DISINFECTANTS. 9 This statement applies as well to many of the articles advertised as ''disinfectants" in this country. But in justice to the manufacturers of these so-called disinfectants, we must say that many of them, which are of no use in the sense in which we use the term, are valuable as antisep- tics or as deodorizers ; and that there is good authority for calling a sub- stance which will prevent putrefactive decomposition, or which will destroy bad odors, a disinfectant. Many chemists and physicians use the word in this sense ; and this is the popular acceptation of the term both in this country and in Europe. We therefore cannot find fault with those manufacturers who see fit to use the word as synonymous with deodorizer or antiseptic ; but we must caution the public that a dis- infectant from this point of view does not necessarily destroy infectious material, and that the word is used by this committee in accordance with the definition given in the introduction to this report. It has been proved that certain kinds of infectious material owe their infecting power to living micro-organisms, which in a general way are often spoken of as 4 * germs." A disinfectant, therefore, which destroys this kind of infectious material may be called a. germicide. If all infec- tious material owes its specific infecting power to the presence of living organisms, then, from our point of view, disinfectant and germicide are synonymous terms. But in the absence of satisfactory proof that such is the fact, we must consider the former term one of general application, while the latter is only applicable in those cases in which the infecting agent has been proved to be a germ. But in our tests of disinfectants we are obliged, for the most part, to depend upon experiments which deter- mine germicide power, and in the experiments reported below, only biological tests have been used. As a matter of fact, those agents which by laboratory experiments have been proved to be the most potent ger- micides, have, by the experience of sanitarians, by tests upon vaccine virus, septicemic blood, etc., been shown to be the most reliable disin- fectants. , Evidently there can be no partial disinfection ; — either the infecting power of the material to be disinfected is destroyed, or it is not. Where the object is to destroy disease germs in the sputum of patients with diphtheria, in the discharges of patients with typhoid fever, etc., so that no development shall occur when these germs find a proper nidus, in- complete destruction will be a waste of ammunition, for so rapid is the multiplication of these low organisms that the question of numbers is of secondary importance. It is therefore essential, in an experimental in- quiry of this kind, that the most rigid tests may be applied, and that we keep on the safe side in the practical application of those agents which withstand these tests. In our experiments below reported, the material which has served to test the germicide power of the agents named is kk broken-down" beef tea, exposed in the laboratory for several days, and containing a variety of putrefactive bacteria and their spores. The spores of Bacillus subtilis are also invariably present in this stock ; and when a certain agent is sue- IO REPORT OF COMMITTEE ON DISINFECTANTS. cessful in destroying all other micro-organisms, we frequently have in our culture-solutions a pure culture of this bacillus, which is noted for its abundant and wide distribution, and for the great resisting power of its spores. In order to meet the objection of those who are likely to cavil because no "disease germs" are present in the material mentioned, a culture of Bacillus anthracis containing spores is added to this stock solution. It is well known that anthrax spores constitute one of the most difficult tests of germicide power, — not more difficult, however, than the spores of B. subtilis. We may safely assume, then, that an agent which will destroy these spores will also destroy all known disease germs, and probably all organisms of this class, known or unknown. The micro- cocci and bacilli, not containing spores, are far more easily destroyed. The time of exposure to the disinfecting agent in all of these experi- ments has been two hours. And the amount of material to be disinfected has, in every case, been made equal to the amount of the solution of the disinfecting agent under trial. Thus, to test an agent in the proportion of fifty per cent., a certain quantity — 10 cc. — of the agent undiluted (ioo percent.) is added to an equal quantity of the broken-down beef stock described. If we wish to test the agent in the proportion of four per cent., an eight per cent, solution is made, and this is added to an equal quantity of the stock, etc. The mixture is placed in a wide-mouthed bottle containing 25 cc, and is set aside for two hours. A minute quan- tity of the material is then introduced into two little culture-flasks 1 (all experiments are made in duplicate) containing sterilized beef tea, and these are placed in the oven, which is kept constantly at a temperature of 36° to 38 C. (96. 8° to 100.4 F.) My method has been explained in detail in a paper relating to an extended series of experiments of a similar nature, published in the American Journal of the Medical Sciences, for April, 1883. These experiments on commercial disinfectants have been very care- fully made, under my direction, by Dr. Duggan. The samples were, for the most part, obtained for me by Dr. Raymond, health commissioner of Brooklyn, and a member of the committee, in the cities of New York and Brooklyn. As the experiments are made in the interests of the pub- lic, special pains have been taken to secure samples such as are placed in the market ; and the rule was adopted at the outset not to test samples sent to us by the manufacturers, but to purchase ourselves such packages as are offered for sale by druggists and other dealers. Numerous experiments were made, but only those are recorded here which fix the limits between success and failure. In four instances, a failure occurred in the proportion of 50 per cent., i. e., when the undi- luted solution was added to an equal quantity of the test material. These agents were at once dropped without further trial. In the table, the agents are arranged with reference to their relative efficiency. iThe flasks used are all made in the laboratory, and are of the form described in the chapter on technology in my book, " Bacteria." REPORT OF COMMITTEE ON DISINFECTANTS. II LIST OF COMMERCIAL DISINFECTANTS TESTED. Per cent, in Per cent, in Name upon Label. which active. which failed. Little's Soluble Phenyle (Morris, Little & Co., Brooklyn), . . 2 I Labarraque's Solution {Liq. soda chlorinata) ; name of manu- facturer not given, 7 5 Liquor Zinci Chloridi (Squibb's), 10 7 Feuchtwanger's Disinfectant (L. Feuchtvvanger & Co., New York), 10 8 Labarraque's Solution (From Frere, Paris), 15 10 Phenol Sodique (Hance Bros. & White, Philadelphia), ... 15 10 ,Platt's Chlorides (Henry B. Piatt, New York), 20 15 Girondin Disinfectant (James Meyer, Jr., New York), ... 25 15 Williamson's Sanitary Fluid (D. D. Williamson, New York), 25 20 Bromo-chloralum (Bromo-Chemical Co., New York), ... 25 20 Blackman Disinfectant ( Blackmail Disinfectant Co., New York) 30 20 Squibb's Solution of Impure Carbolic Acid (about 2 per cent.), 50 Burchardt's Disinfectant (J. H. Harty & Co., New York,) 50 Phenol Sodique (7 Rue Coq. Heron, Paris), 50 Listerine (Lambert & Co., St. Louis), 50 I append to this list the report made by Wynter Blyth (loc. cit.) upon certain commercial disinfectants exhibited at the London Health Exhi- bition : Various Tar-Acid Disinfectants. Jeyes's perfect purifier, the concentrated carbolated creo- sote of Messrs. D. & W. Gibb, the kresylene described by Messrs. Mackay & Co. as a preparation of coal-tar creosote, pixene, and the thymo-cresol exhibited by Messrs. Ness & Co., have all the property of emulsifying with water. Jeyes's purifier was for some time tried in St. Marylebone urinals and drains, but the deposit left on the surface with which it had been in contact was found difficult to cleanse, and inconvenient. I have made some experiments on anthrax in the spore state with the " perfect purifier." The solu- tions used were 5 to 10 per cent. ; the " fluff" had to be freed from the tenacious fawn- colored deposit by alcohol. The result was very similar to what might have been pre- dicted from results of experiments on the pure tar-acids, viz., growth was a little delayed, but never destroyed. Mr. James Wheeler's pixene I was, on the whole, favorably impressed with. He claims to have condensed the whole of the volatile constituents of pure tar, and to have present- ed them in a form readily miscible with water. * * * Anthrax spores soaked in a ten per cent, solution did not grow for some time. Carbolic Acid Powders. I have experimented on anthrax with Calvert's, Jeyes's, and McDougall's powders ; but, even when a paste was made with the several powders, and the infected " fluff" allowed to remain therein twenty-four hours, no sterilization resulted. Similar powders were obtained by our committee in New York and Brooklyn, but I have not thought it worth while to make any experi- ments with them, as sawdust or other material, saturated with impure carbolic acid or with the volatile constituents of tar, can have no great value in view of the low disinfecting power of these agents minus the sawdust. An agent which has gained considerable reputation in Eng- land is referred to as follows by Blyth : Sanitas. Of all the substances introduced under the name of disinfectant, this is the most pleasant. Sanitas is chiefly in the form of sanitas oil and sanitas fluid : peroxide of 12 REPORT OF COMMITTEE ON DISINFECTANTS. hydrogen, thymol, camphoric acid, and terebene enter into their composition. Of the numerous sanitas preparations, liquid and solid, the oil seems to be the most active. Nothing replaces or destroys so rapidly the unpleasant odor which tenaciously adheres to hands contaminated by offensive animal matters. It is also to be commended for use in stables, and as a corrective for dung-heaps, and of the sickly smell at times rising frorh the metropolitan wood pavement. I made many experiments with sanitas on anthrax. Spores soaked in sanitas fluid for twenty-four hours grew afterwards very freely. Spores placed in the undiluted emulsion, and afterwards removed, seemed at first to have their growth delayed ; but in forty-eight hours growth commenced, and ultimately became lux- uriant. The oil itself gave similar results. Sanitas powder was also tried, but with no better success. Returning to the disinfectants in our list, it will be seen that all but the four last named are efficient in various amounts, ranging from 30 to 2 per cent. But the relative value of the agents as here given does not estab- lish their comparative practical value as disinfectants. Questions of cost, physical and chemical properties, etc., come into the account, which it is the province of other members of our committee to consider. We have nothing to say against the use of any of the agents in our lists as antiseptics or as deodorizers. No doubt all of them are more or less useful for this purpose, and we have no desire to restrict their use. But the exaggerated claims made in relation to the germicide or disinfectant power of certain of these agents, may do immense harm. Thus, one agent advertised asa " germicide" par excellence, " Pasteur's marvellous disinfectant," which failed after two hours' exposure to kill the organ- isms in our test solution in the proportion of 20 per cent. Yet this fluid is, by some contrivance, to be thrown into the water-closet of every germ- fearing citizen when he pulls the handle, so that it may catch the germs on the fly, and extinguish their power for mischief before they reach the sewers. On the whole, the proprietary disinfectants have turned out better than I anticipated ; and any one of the eleven first named may be used in conformity with the conditions imposed by the experimental test for disinfecting sputum or excreta. For fecal matter, however, it will be best to employ an agent which is successful in the proportion of ten per cent., — for example, in at least twice this strength, and in quantity considerably in excess of the material to be disinfected. It must be remembered, that in our experiments the germs are suspended in a fluid, and this is thoroughly mixed with the disinfectant. The second agent in our list is the well known liquor sodce chlorinate. Our experiments lead me to think that this time-honored disinfectant is worthy of more attention than it receives to-day, when so many other agents of inferior value are being pushed by enterprising manufacturers. Our two samples differ greatly in their disinfecting power, which de- pends upon the amount of sodium hypochlorite present. Dr. Duggan has prepared and experimented with a solution containing six per cent, of available chlorine, which proves to be efficient in the proportion of •one per cent. I am informed that a solution containing two per cent, of available chlorine could be put in the market for less than forty cents per gallon. Whether this is to be the disinfectant with which we shall fight REPORT OF COMMITTEE ON DISINFECTANTS. 1 3 cholera must be determined by my colleagues, who take up the question from a practical standpoint. But whatever agents are determined to be the best, must be so cheap that they may be obtained by the gallon, and used without stint. The time has passed when pater familias can com- placently congratulate himself upon having disinfected his house with a bottle of carbolic acid, which he has brought in his vest pocket from the corner drug store. In view of the efficiency and cheapness of the hypochlorites, I have requested Dr. Duggan to give special attention to these agents, and to prepare a report, embodying the results of his biological tests, and such information relating to the modus operandi, chemical characters, and available tests of strength, as may be useful to health officers and to the public. GERMICIDE POWER OF THE HYPOCHLORITES. BY J. R. DUGGAN, M. D., PH. D. In my previous work on commercial disinfectants, I found that the specimens of Labarraque's solution of sodium hypochlorite, although containing only a small quantity of this salt, were among the most effec- tive in their action. On looking over the literature of the subject, I found that although this solution and that of the corresponding calcium salt (chloride of lime) were among the first used disinfectants, very little had been done to fix accurately their value. In order to determine this, I prepared standard solutions of sodium and calcium hypochlorites for use in the following experiments. The available chlorine, that is, the chlorine which enters into the constitution of the hypochlorites, was determined in these solutions by its oxidizing action on a standard solu- tion of arsenious acid, — papers saturated with starch paste and potassium iodide being used to show an excess of the hypochlorite. The well known method of Dr. Sternberg was used throughout the investigation to determine germicidal value. The following solutions were prepared : Solution A. Sodium hypochlorite made by passing chlorine gas into a solution of sodium hydroxide. Available chlorine = 6 per cent. Solution B. Calcium hypochlorite made by passing chlorine gas into milk of lime. Available chlorine = 6 per cent. Solution C. Calcium hypochlorite made by dissolving ioo grammes of bleaching powder (chloride of lime) in I litre of water, and filtering. Available chlorine = 2.4 per cent. Solution D. Potassium hypochlorite made by passing chlorine gas into a solution of potassium hydroxide, and diluting until the available chlorine = 1 per cent. The action of Solution A on spores of Bacillus anthracis was tried with the following result : 2 per cent, was effective in 30 minutes, 1 hour, and 2 hours ; 1 per cent, failed in 1 hour, effective in 2 hours. 14 REPORT OF COMMITTEE ON DISINFECTANTS. Solution B in 2 per cent, gave similar results. In i per cent, it was effective in both i and 2 hours. Solutions A and B were both found to be effective in 5 per cent, and 1 minute's time on the organisms of broken-down beef tea. One half per cent, of these solutions failed to destroy in 2 hours organisms in broken- down beef tea, but 1 per cent, of Solution A was effective in the same time. One of the bulbs from a 1 per cent, solution of Solution B broke down, but the other remained clear. These solutions were also tried in 2 and 3 per cent, for 2 hours, and found effective. Solution C was effective in 3 per cent., but failed in 1 and 2 per cent, in 2 hours. Solution D was effective in 7 per cent., but failed in 5 and 6 per cent, in 2 hours. In addition to these, we may mention a dilute solution of bleaching- powder of unknown manufacture. This contained 4 per cent, available chlorine, and was effective in 15 per cent., failed in 10 per cent: ; time, 2 hours. The commercial specimens of Labarraque's solution, reported among the commercial disinfectants, showed about the same value in proportion to the available chlorine they contained. These latter experi- ments were all made on broken-down beef tea. That this contained spores as well as organisms was shown by the fact that tubes inoculated from the solution while boiling developed various bacilli. Of course, spores must have been present to resist this temperature. While it has been thought well to use a pathogenic organism in some of these experiments, I am convinced, from recent works on the subject, that any agent that will destroy Bacillus subtilis will also destroy B. an- t/iracis, and probably any other pathogenic organism. The foregoing experiments show that a solution containing .25 of 1 per cent. (1 part to 400) of chlorine, as hypochlorite, is an effective germ- icide, even when allowed to act for only one or two minutes, while .06 of 1 percent. (6 parts to 10,000) will kill spores of B. ant/zracis and B. subtilis in two hours. A simple calculation will show that all the solutions used were effective when diluted to about this strength, and failed a little below it. No better evidence could be had of the reliability of the excellent method of Dr. Sternberg for testing agents of this kind. These experiments were all made in duplicate, and they show a concord- ance which I am satisfied can be obtained by no other method with which I am acquainted. The value of the various commercial preparations, such as Labar- raque's solution and bleaching-powder (chloride of lime), of course de- pends on the amount of available chlorine they contain, since the chlo- rides and chlorates are of very little value as disinfectants. Bleaching- powder usually contains from 25 to 40 per cent, of available chlorine. For most purposes a solution containing 1 part of this preparation to 100 of water is strong enough, for this will contain from .25 to .40 of 1 per cent, of chlorine as hypochlorite. As is stated above, the smaller of these quantities is sufficient to destroy spores almost instantly. There REPORT OF COMMITTEE ON DISINFECTANTS. 1 5 are very few purposes to which disinfectants are applied that are not fulfilled by this solution of 1 to 100 of bleaching-powder. It is not poi- sonous, does not injure clothing, bedding, etc., and is almost without cost, since bleaching-powder is worth only about five cents per pound. The sodium salt furnishes in some respects a more elegant preparation, since it leaves on evaporation sodium chloride, instead of the hygroscopic calcium chloride. If prepared according to the U. S. P., it does not keep very well ; but when made by passing chlorine gas into a solution of an excess of caustic soda, it shows very little tendency to undergo de- composition. Solution A, although rather concentrated, and frequently exposed to the light and air, has kept for a month without any appreciable change. A solution like this might be put on the market at a very reasonable price, and as it should be diluted with 20 parts of water, it would be far cheaper and more effective than any of the proprietary disinfectants. The odor of the hypochlorites is a slight objection to their use, but in dilute solution this is scarcely disagreeable. Where the odor is not to be re- garded, the hypochlorous acid may be liberated by the addition of any common acid, thus increasing the oxidizing power, and liberating a most effective gaseous disinfectant. I hope to make further experiments on this point at an early day. To fix the value of solutions of the hypochlorites, the following method is sufficiently accurate for ordinary purposes : A standard solution of potassium arsenite may be made by diluting seven parts of Fowler's so- lution with one and a half parts of water. This corresponds to a y 2 per cent, solution of available chlorine. To apply the method, a given vol- ume of the hypochlorite solution is measured out, and the arsenite solu- tion added in small quantities. Between each addition the mixture is well stirred, and a drop taken out on a glass rod, and tested on a strip of paper saturated with iodide of potassium and starch paste, and dried. So long as any hypochlorite is present, the blue iodide of starch is formed ; but when it has all been used up in converting the arsenite into an arseniate, the paper will remain colorless. As each volume of the potassium arsenite solution required for this corresponds to y? per cent, of available chlorine, the calculation is very simple ; e. g., if one volume of the hypochlorite solution = 4.6 volumes of the arsenite solution, the amount of available chlorine present would correspond to 2.3 per cent. Since the preparations now on the market vary so much in the amount of chlorine they contain, this test should always be used to determine their value, and the amount of dilution required. Where the disinfectant is further diluted in use by being added to liquids or semi-solids, the orig- inal dilution should not be so great. The hypochlorites possess the advantage over many of the metallic salts of not forming a coating of insoluble albuminoid matter around the solid or semi-solid masses, and thus protecting them from further action. On the contrary, when used in moderately strong solution they oxidize and disintegrate these materials. They are at the same time destroyed 1 6 REPORT OF COMMITTEE ON DISINFECTANTS. themselves in the reaction, so that we are rid of germs, organic matter, and disinfectant all at the same time. Note. The fact that the oxidizing disinfectants are destroyed in the reaction to which their disinfecting power is due, makes it necessary to use them in excess of the amount of organic material to be destroyed, otherwise germs included in masses of material not acted upon would be left intact in a fluid which is no longer of any value for their de- struction ; and as a few germs may be as potent for mischief as a large number, there would be a complete failure to accomplish the object in view. For this reason, the me- tallic salts, such as mercuric chloride, which are not destroyed by contact with organic material, have a superior value for the disinfection of masses of material left in situ, such as the contents of privy vaults and cesspools. In this case, even if germs enclosed in an envelope of the albuminate of mercury escape destruction, they will be prevented from doing mischief so long as they are included in such an envelope, and the wonderful anti- septic power of the agent used will prevent any development, probably for a sufficient length of time to insure the complete loss of vitality of any pathogenic organisms present. George M. Sternberg. COMMERCIAL DISINFECTANTS. No. 2. BY GEORGE M. STERNBERG. The following named " disinfectants" have been tested, under my di- rection, by my efficient laboratory assistant, Dr. A. C. Abbott, of Balti- more. The test in every case has been made upon '* broken-down" beef tea, by the method heretofore described in detail. Several of the disinfectants which stand at the head of the list contain the potent germicide, mercuric chloride, as shown by the simple test of introducing a polished piece of copper into the solution. A deposit of metallic mercury upon the surface of the copper shows at once the pres- ence of a soluble salt of this metal. Those who have occasion to use dis- infectants, the exact composition of which is not made public, will do well to bear this in mind, and to remember, also, that the germicide power of such solutions is neutralized by contact with lead, copper, or tin, and that lead pipes are injured by passing through them solutions of corrosive sublimate in any considerable quantity. Per cent, in Per cent, in Name upon label. which active. which failed. Dr. Martin's " Disinfectant No. 1 " (contains mercuric chlo- ride) 2 1 " Thymo-cresol," English preparation, name of proprietor not given . 2 1 " Withers's Antizymotic Solution " (contains mercuric chlo- ride) 4 2 "Pasteur's Marvellous Disinfectant," 1 Blackman Disinfectant Co., of New York (contains mercuric chloride) 4 2 " Purity," Egyptian Chemical Co., Boston 40 20 " King Disinfectant," Humiston Manufacturing Co., New Haven, Conn 50 " Sanguantrae," P. W. Manning, Stoneham, Mass., .... 50 "Phenoline," Hance Bros. & White, Philadelphia .... 50 "Golden Purifier," Thomas & Thompson, Baltimore ... 50 1 A preparation bearing the same name, reported upon in previous report upon commercial disin- fectants, did not contain mercuric chloride, and failed at 20 per cent. REPORT OF COMMITTEE ON DISINFECTANTS. 1 7 Per cent, in Per cent, in Name upon label. which active. which failed. * Smith's Odorless Disinfectant," the Louis Smith Co., New York 50 " Disinfecting Powder," G. L. Kidwell, Georgetown, D. C. . 50 " Thymo-cresol Powder," English preparation, name of pro- prietor not given 50 "Chloridium," Chemical Vaporizer and Deodorizer Co., of New York 50 " Carbolcrystal Disinfectant," H. H. Childs, proprietor . . 50 Dr. Abbott has also tested for me the different preparations of chloride of lime, and of Labarraque's solution, which we have been able to obtain in the Baltimore market, with the following result : Per cent. CHLORIDE OF LIME. of available chlorine. Brookman Manufacturing Co., Chicago 33-5° Risley & Co., New York 28.40 Rock Hill Alkali Co., Liverpool 28.00 Clagett Bros 24.10 LABARRAQUE'S SOLUTION (LIQUOR SOD.E CHLORINATE). Reed & Carnrick, New York 3.80 Parke, Davis & Co., Detroit, Mich 2.75 Powers & Weightman, Philadelphia 2.62 Hance Bros. & White, Philadelphia 0.35 Alonzo L. Thompson, Baltimore 0.013 NOTES. 1 BY THE CHAIRMAN OF THE COMMITTEE. My attention has just been called to an advertisement of " Withers's Antizymotic Solution," in which it is stated that it is endorsed as the best by George M. Sternberg, M. D., Surgeon U. S. A. I have never authorized the use of my name in connection with this or any other proprietary disinfectant. The only reference I have ever made to " Withers's Antizymotic Solution " is in the report on " Commercial Disinfectants," No. 2, 2 published in the Medical News of June 13th, where this has the third place in a list of fourteen commercial disinfect- ants, tested under my direction by Dr. Abbott. The remark is made, " Contains mercuric chloride." As a simple solution of mercuric chlo- ride of 1 : 500 would be quite as efficient as a 4 per cent, solution of this disinfectant, the extravagant claims made for it are without foundation. The assertion that it is endorsed by me "as the best" is untrue. Labarraque's Solution. I have received the following letter from a well known and reputable firm of manufacturing chemists : 1 Medical News, Sept. 5, 1885. * See ante, p. 16. 1 8 REPORT OF COMMITTEE ON DISINFECTANTS. In the Medical A r ews (Philadelphia) for June 13th we find a continuation of the Prelim- inary Report of the Committee on Disinfectants, including a report on the relative per- centage of available chlorine in samples of different manufacturers of Labarraque's Solu- tion. As you are doubtless aware, Labarraque's Solution is a very unstable preparation; and, although made with every possible care, will surely deteriorate by age. With such an article it is manifestly unfair to institute comparisons between different makers, with- out regard to the freshness, or otherwise, of the samples. To the unthinking reader, the bald statement that one preparation contains 3.8 per cent., and another only .013 per cent., is calculated to convey the impression that the preparation which contained so small a percentage has been improperly made (while really, when fresh, its percentage might have been greater than the highest named) ; and such an impression would naturally cre- ate a prejudice against the manufacturer, and, unfortunately, not be limited to the partic- ular article mentioned. I recognize the fact that the unthinking reader might make an infer- ence unfair to the manufacturer, from the perusal of a "bald statement" such as is published in the table on page 659 of the News. I regret this, and will in future gladly give the date of manufacture, if the manufac- turers will stamp it upon the bottle. As I propose to obtain new samples from time to time, and to publish the results of tests as to available chlo- rine, it may happen that the aggrieved manufacturers in this instance will come out at the head of the list next time. But these tests are made especially in the interests of the public, which, from my point of view, are superior to those of the manufacturers ; and it is evident that great harm might result from reliance upon the disinfecting power of a liquid labelled " Labarraque's Solution," which contained only .013 per cent, of available chlorine. The fact that it was of full strength when first manufactured does not add to its value as a disinfectant for the excreta of a patient with cholera or typhoid fever. If the manufacturers will stamp the date of manufacture upon the label attached to each bottle, I will publish it, in future, it connection with the result of the tests to determine available chlorine present in the solution. POTASSIUM PERMANGANATE. BY GEORGE M. STERNBERG. In my experiments made in Baltimore in 1881 1 it was found that a 2 per cent, solution of potassium permanganate was required to destroy the virulence of septicemic blood, the test of disinfection being inocula- tion into healthy rabbits. In experiments made in San Francisco in 1883 2 it was found that .12 per cent. (=1 : 833) destroyed the micro- coccus of pus in culture solutions. As the virulence of the blood in the first experiments was demonstrated to be due to the presence of a micro- coccus which has, as a rule, less resisting power for chemical agents than has the micrococcus used in the .second series of experiments, it ^'Bulletin National Board of Health," July 23, 1881 : also, "Studies from Biological Laboratory of Johns Hopkins University," vol. ii, No. 2. 2 Am. Journal of the Medical Sciences, April, 1883. REPORT OF COMMITTEE ON DISINFECTANTS. 1 9 may be thought that these results are contradictory. This is not, how- ever, the case, and the wide difference as to the quantity of the disinfect- ing agent required in the two series of experiments depends upon an essential difference in the nature of the fluid in which the germs to be destroyed were contained. The large amount of organic material pres- ent in the blood as compared with that in the culture fluid used in the second series of experiments fully accounts for the difference, for the dis- infecting agent is itself quickly destroyed by contact with organic mat- ter ; and, indeed, its disinfecting power depends upon this instability of composition, and upon the oxidation of organic material with which it comes in contact. This difference in the result, due to a difference in the amount of organic matter present in the material to be disinfected, is further exem- plified in the following experiments : November 26, 1884, a single drop of a pure culture of micrococcus of pus was subjected to the action of potassium permanganate for two hours, in the proportion of 1 part to 500, and in the proportion of I part to 1,000. Four culture-tubes containing a sterilized solution of beef-pep- tone were inoculated with the micrococci thus exposed (it is my practice to make every experiment in duplicate), and were placed in a culture- oven maintained at 38 C. (100.4 F.) for forty-eight hours. No devel- opment occurred in either of the tubes. On the 29th of November a similar experiment was made with a culture solution containing both micrococci and bacilli. In this exper- iment there was no development of the micrococci, but the bacilli devel- oped abundantly after exposure to the 1 : 1000 solution. No develop- ment of bacilli ( B. subtilis) occurred, however, after exposure to 1 part in 250. In these experiments the permanganate, although in dilute solu- tion, was not neutralized by the small amount of organic material con- tained in the drop of the culture fluid exposed to the action of the germi- cide agent. In the following experiments the conditions were varied, and a larger proportion of the permanganate failed to exert any germicide power. November 24 equal parts of a .4 per cent, solution (1 : 250) of potas- sium permanganate and of " broken-down " beef tea were mixed in a germ-proof receptacle, and allowed to stand for two hours. Two cul- ture-tubes were then inoculated with a minute drop of the mixture, and were placed in the oven. At the end of twenty-four hours an abundant development of putrefactive bacteria had taken place. In this experi- ment, then, we have a failure in the proportion of 1 : 500, but the exper- iment does not in the least invalidate those previously reported. The truth is, that in making the above mixture the permanganate is almost instantly decomposed by the excess of organic matter, while in the exper- iments in which a single drop of culture-fluid containing micrococci was introduced into a more dilute solution, there was still an excess of the permanganate, as shown by the color of the solution at the end of two hours. Having determined the germicide power of the permanganate 20 REPORT OF COMMITTEE ON DISINFECTANTS. for micrococci, at least for one species of micrococcus, I desired to know whether the oxidizing power of this reagent, when present in excess, would destroy the spores of anthrax, which are recognized as furnishing one of the most difficult tests of germicide power. The following exper- iments have been recently made : November 24 a drop of culture fluid containing an abundance of an- thrax spores, a pure culture, was added to a considerable quantity of a .4 per cent. (1 : 250) solution of potassium permanganate. After two hours two culture-tubes were inoculated with a minute quantity of this material. These tubes were placed in the culture-oven, and the follow- ing morning contained an abundance of anthrax bacilli. November 27 the above experiment was repeated, except that the time of exposure was extended to four hours. Again there was an abundant development of anthrax bacilli in the culture-tubes, showing that the spores had resisted ; but in one tube the development was delayed, and it was only on the morning of the second day that flocculi of bacillus anthracis commenced to appear. December 2 the experiment was repeated, with the exception that the time of exposure was extended to four days. The bacillus now failed entirely to develop in the culture-tubes, showing that the spores had been killed by this long exposure. It is probable that in experiments in which the permanganate is pres- ent in excess, the amount present is of less importance than the time of exposure, and that a stronger solution would fail to destroy anthrax spores in a considerably shorter time. The resisting power of anthrax spores to this reagent is shown by these experiments to be greater than that of the spores of B. subtilis. This is true also of chloride of zinc, and no doubt of certain other chemical agents. On the other hand, the spores of B. subtilis have a greater resisting power for heat. These dif- ferences in resisting power show that it will be necessary to exercise due caution in applying the data obtained in experiments upon one pathogenic organism in our practical efforts to disinfect material containing a differ- ent organism. According to Arloing, Cornevin, and Thomas, a 5 per cent, solution destroys the fresh virus of symptomatic anthrax, but has no effect upon the dried virus. One per cent, was found by Koch not to destroy the spores of anthrax, but in the proportion of 1 : 3000 the development of these spores was retarded. The experiments of De la Croix, like those of Miquel, have reference especially to the antiseptic power of the agents tested by him. He makes the statement, however, that one part of potassium permanganate in thirty-five kills the bacteria of broken-down beef tea. This statement is no doubt true under the conditions of his experiment; but, as I have shown, the result depends upon the time of exposure and the amount of organic matter present quite as much as upon the proportionate amount of permanganate with reference to the quantity of fluid operated upon. REPORT OF COMMITTEE ON DISINFECTANTS. 21 If we add one gramme of permanganate to a litre of broked-down beef stock, it is quickly decomposed, and no germicide effect is produced ; but if we add one drop of putrid beef tea to a litre of distilled water con- taining one gramme of permanganate, the organic matter, and the germs as well, contained in this drop of fluid are quickly destroyed by oxida- tion. Several English investigators — Notter, 1 Calvert, 2 and Tripe 3 — have attempted to determine the value of potassium permanganate as a " dis- infectant ;" but the methods employed have not been such as could give satisfactory and definite results, although these earlier experiments demon- strated the value of this agent as an antiseptic and deodorizer. Other English investigators — Baxter, 4 Braid wood, and Vacher 5 — have adopted a different test, and their results are interesting and valuable. These gentlemen operated upon vaccine lymph, and the test of disin- fection was the failure of this lymph to produce characteristic vesicles upon the arms of children not previously vaccinated. Comparative ex- periments were made in each case with lymph not subjected to the action of the disinfectant. In Baxter's experiments i part in 200 was successful in destroying the specific virulence of vaccine lymph ; and in those of Braidwood and Vacher a like result was obtained by adding two drops of a solution of 1 : 120 to " a tube of lymph." From what has been said, it is evident that while potassium perman- ganate has decided germicide and antiseptic power, it is not generally applicable for purposes of disinfection, because of the readiness with which it is decomposed by organic matter. It is, however, a prompt and valuable deodorizer. HYDROGEN PEROXIDE. BY GEORGE M. STERNBERG. Since Angus Smith, in 1869, proclaimed his belief that peroxide of hydrogen was to be the disinfectant of the future, sanitarians have been waiting for chemists to devise some method by which this agent may be manufactured at a sufficiently low price to bring it into general use. The absence of any corrosive or poisonous properties, or of any objec- tionable odor, and the jM'omptness with which this agent destroys vola- tile putrefactive products and arrests putrefactive decomposition, seemed to make it the disinfectant far excellence. But we no longer accept the arrest of putrefactive decomposition or the destruction of bad odors as 1 Dr. J. Lane Notter, " Dublin Journal of Medical Sciences," vol. Ixviii (1879), p. 196. 2 Dr. Grace Calvert, "Chemical News," London, vol. xxii (1S70), p. 281. 3 Dr. John W. Tripe, " Sanitary Record," London, vol. ii (1881), p. 201. * Dr. E. B. Baxter, " Report on the Experimental Study of Certain Disinfectants." " Report Med- ical Officer Privy Council," etc., N. S. No. vi (1875), p. 216. fi " British Medical Journal," London, vol. ii (1876). 22 REPORT OF COMMITTEE ON DISINFECTANTS. evidence of disinfecting power, and the question which here concerns us relates to the power of this agent to destroy germs. The following experiments have been made by Dr. Duggan and my- self with a solution of hydrogen peroxide prepared under the direction of Prof. Albert R. Leeds, a member of the Committee on Disinfectants. When first received from Dr. Leeds this solution contained 4.S per cent. of H 2 2 , and 5 per cent, of sulphuric acid. At the expiration of a month the amount of hydrogen peroxide was again estimated by Dr. Duggan, and was found to be 3.98 per cent. Five weeks later the proportion was reduced to 2.4 per cent. The constant escape of oxygen at the tempera- ture of the laboratory is shown by a continuous flow of minute bubbles from the interior of the liquid to its surface. Tested upon broken-down beef tea, when the proportion of H 2 2 was 3.98 per cent, (say 4 per cent.), the solution was found to be active in the proportion of 30 per cent., while it failed in the proportion of 20 per cent. ; that is to say, 1.2 per cent, of H 2 O a in two hours' time destroyed all the organisms present in the broken-down beef stock, and .8 per cent, failed to do so. Tested upon a pure culture of B. anthracis containing spores, the same solu- tion was effective in 20 per cent. (.8 per cent. H 2 2 = 1:125), anc ^ failed in 10 per cent. Tested upon a pure culture of a micrococcus, ob- tained from a drop of blood drawn from the inflamed area in a case of vaccinal erysipelas, the same solution was effective in the proportion of 10 per cent. (.4 per cent. ofH 2 2 =i :25c)), and failed at 5 per cent. In experiments made at a later date (March 28) , when the strength of the solution was reduced to 2.4 per cent., micrococcus tetragenus was destroyed by 10 per cent. (.24 per cent. H 2 2 z= 1 =400), while the same amount failed to destroy the vitality of the micrococcus of pus, — pure culture obtained from an acute abscess, — showing a difference in the resisting power of these two organisms. As the solution used in these experiments contained 5 per cent, of sul- phuric acid, which in a previous series of experiments 1 has been shown by the writer to be fatal to the micrococcus of pus in the proportion of 1 : 200, it is evident that a failure to destroy the vitality of the same micro- coccus in 1 : 400 does not give this solution any very notable advantage over a simple aqueous solution of sulphuric acid. The germicide power of the solution used, as tested by its action upon spores, is, however, considerably above that of sulphuric acid alone. Dr. Duggan has ascer- tained that to destroy all of the organisms in broken-down beef tea re- quires 8 per cent, of H 2 S0 4 , whereas 30 per cent, of our solution of H 2 2 , containing 5 per cent, of sulphuric acid (=1.5 per cent, of H 2 S0 4 ), is effective. These experiments indicate that unless chemists can furnish us solu- tions which are more concentrated and which will keep better, we are not likely to derive any great practical benefit from the use of hydrogen peroxide as a disinfectant. As an antiseptic, our solution was found by Dr. Duggan to be effective 1 American Journal of the Medical Sciences, April, 1883. REPORT OF COMMITTEE ON DISINFECTANTS. 2$ in the proportion of i : 5000 (of H 2 2 , not of the dilute solution), and to fail in the proportion of 1 : 10,000. This does not correspond with the results reported by Miquel, who places hydrogen peroxide — eau oxy- genec — above mercuric chloride as an antiseptic. In his table of the minimum amount of different antiseptic agents which will prevent the putrefaction of one litre of neutralized beef tea, the quantity of H 2 2 required is stated to be .05 gramme (1 : 20,000), while the amount of mercuric chloride required to accomplish the same results is given as .07 gramme (= 1 : 14,285). CHLORINE, BROMINE, AND IODINE. BY GEORGE H. ROHE. Chlorine. — The most thorough and exact research into the disinfect- ant powers of chlorine on record is that made by Fischer and Proskauer, and published in the second volume of Mittheilungen aus dent Kaiser- lichen Gesundheitsamtc. The material tested consisted of the spores of bacillus anthracis, spores of the various forms of bacilli found in ordinary garden soil, micrococcus tetragenus, micrococcus prodigiosus, bacillus of septicaemia of mice, bacillus of septicaemia of rabbits, aspergillus ni- grescens and aspergillus ruber, micrococcus of erysipelas, sputum of tuberculosis, bacillus anthracis, bacterium of fowl cholera, and various other non-pathogenic micro-organisms. The observations were made both in dry air and in air artificially moistened, and the objects to be disinfected were sometimes exposed in a dry, sometimes in a moist, condition. The concentration of the gas varied from 1 part in 25,000 to 1 part in 2J. The time of exposure in the different experiments varied from one to twenty-four hours. Anthrax spores, when thoroughly desiccated and exposed to the action of a dry chlorine atmosphere containing 44.7 parts of chlorine in 100, resisted the disinfectant action of the agent completely for one hour. After three hours' exposure, germination w r as still free, but somewhat retarded. After twenty-four hours' exposure, disinfection was complete, the vitality of the organism being entirely destroyed. When the air in the experimental chamber and the spores were mois- tened, one hour's exposure to an atmosphere containing 4 per cent, of chlorine was sufficient to produce complete disinfection. If the exposure was continued for three hours, 1 per cent, of chlorine was an efficient disinfectant ; and if the spores were exposed for twenty-four hours, the effective proportion of chlorine could be still further reduced if the air and objects to be disinfected were first rendered moist. Bacillus anthracis itself was killed in moist air, if chlorine was present, in the proportion of 1 part in 2,500 after twenty-four hours' exposure. Even with such a minute proportion of chlorine as 1 part in 25,000, the development of the organism was scanty and retarded. 24 REPORT OF COMMITTEE OAT DISINFECTANTS. Spores of the various forms of bacilli found in ordinary garden soil proved a little more resistant to the action of the chlorine. When the air in the experimental chamber was very moist, however, the presence of i per cent, of chlorine, and upward, rendered the spores incapable of development after three hours' exposure. When the chlorine strength was 4 per cent., one hour's exposure was sufficient to destroy the germi- native power of these spores. Micrococcus tetragenus was killed in moist air by the presence of so small a proportion of chlorine as i in 25,000, if the exposure was pro- longed to twenty-four hours. Exposure for less than three hours was not sufficient to destroy the life of the organisms in all cases. Micrococcus prodigiosus, and several other varieties of pigment-form- ing micrococci, showed themselves generally more resistant to the disin- fectant than micrococcus tetragenus. In other respects they behaved similarly, exposure for upward of three hours being sufficient to destroy them in the presence of over 4 joer cent, of chlorine. Aspergillus nigrescens and aspergillus ruber were rendered incapable of further growth by exposure for one hour to moist air containing 1 part of chlorine in 25,000. Micrococcus of erysipelas was killed by three hours' exposure to moist air containing 1 part of chlorine in 2,500, or twenty-four hours' exposure to air containing 1 in 25,000. Bacillus of septicaemia of mice was killed by exposure to an atmos- phere containing from 3 to 40 parts of chlorine in 1,000. The presence of 5 parts in 1 ,000 was effective after one hour's exposure in a moist atmosphere. Bacillus of septicaemia of rabbits was killed by an exposure of twenty- four hours to 5 parts in 1,000, and after one hour's exposure to 40 parts in 1 ,000, but retained its infective properties after one hour's exposure to 5 parts in 1,000. Tuberculous sputum was disinfected after one hour's exposure to an atmosphere containing 5 parts of chlorine in 1,000. Bacterium of fowl cholera was destroyed after exposure for twenty- four hours to a moist atmosphere containing 1 part of chlorine in 25,000. Dr. G. M. Sternberg (Report National Board of Health, 1880, p. 320) tested the effect of chlorine upon dried vaccine lymph and the micro- organisms of putrid urine. Six hours' exposure of vaccine lymph, dried upon ivory points, to an atmosphere containing 1 part of chlorine in 200 was sufficient to destroy the infective property of the lymph, as tested by subsequent inoculation. In one experiment five points were exposed to an atmosphere containing 1 per cent, of chlorine. Of these, four were disinfected, while the fifth furnished a satisfactory vaccine vesicle. The failure in this case is explained by Dr. Sternberg by the assumption of an unusually thick coating of dried lymph. In these experiments con- trol-inoculations with non-disinfected virus from the same packages were made in all cases. The bacteria of putrid urine were destroyed after six hours' exposure to an atmosphere containing 1 part of chlorine in 400. REPORT OF COMMITTEE ON DISINFECTANTS. 2$ Braidwood and Vacher (" Report of Life-History of Contagium," British Medical Journal, 1876, vol. ii) mixed liquid vaccine virus with equal parts of liquor chlori (B. P.), and completely destroyed the infec- tivity of the vaccine. The time of exposure is not stated. Dr. E. B. Baxter (Report of Medical Officer Privy Council, 1875), tested the effect of chlorine on liquid and dry vaccine, and on the "virus of infective inflammation." The infectivity of the latter was destroyed by the presence of 8 to 15 parts of chlorine in 10,000. The time of ex- posure to the action of the disinfectant is not stated. The experiments of Dr. Baxter on vaccine lymph are not detailed with sufficient exactness to allow trustworthy conclusions to be drawn. He states, however, that ** unless the chlorine was present in sufficient quantity to render the lymph acid, it had no effect." Koch ( Mitthcilungen a. d. Kais. Gesundheitsamte, Bd. I, p. 263) found that anthrax spores lost their power of development when im- mersed for twenty-four hours in chlorine water. Fischer and Proskauer, in addition to testing the influence of chlorine on micro-life, also exposed a number of fabrics, colored leather, and wearing apparel to the action of this agent. All the colored articles were either bleached or much altered in color. They conclude their elaborate memoir with the following observation : Disinfection with chlorine is attended by great inconvenience on account of the rapid evolution of the gas froin the chlorinated li?ne and hydrochloric acid when mixed, and the very irritant action of the gas upon the mucous me?nbrane of the larynx and of the eyes. Clothing is also liable to be discolored by the action of this disinfectant. Bromine. — Fischer and Proskauer (ibid.) also studied the effect of the vapor of bromine upon spores of bacillus anthracis, spores of garden soil bacilli, tuberculous sputum, bacillus anthracis, micrococcus prodigiosus, micrococcus tetragenus, micrococcus of erysipelas, aspergillus nigrescens, Aspergillus ruber, and several other non-pathogenic organisms. After an exposure of three hours in a dry atmosphere containing 3 parts of bromine vapor in 100, the anthrax bacillus, tuberculous sputum, and both aspergillus species were entirely disinfected. The spore-bear- ing organisms and the non-pathogenic micrococci retained their power of development, although generally in a diminished degree. After moistening the air in the experimental chamber to the greatest attainable degree, three hours' exposure to an atmosphere containing 1 part of bro- mine in 500 acted as a thorough disinfectant; if the exposure was pro- longed to twenty-four hours, 1 part in 3,500 was efficient. When the proportion of bromine was reduced to 1 part in 16,000, exposure for twenty-four hours failed to disinfect spore-bearing organisms. Upon the whole, bromine did not prove as prompt a disinfectant as chlorine, besides being very difficult and dangerous to handle. Koch x found a 2 per cent, aqueous solution of bromine effective against anthrax spores after twenty-four hours' exposure. 1 Loco cit. WlVttRSITV OP CALIFORNIA UPAftTMIttW tH» NOMH ECONOMICS 26 REPORT OF COMMITTEE ON DISINFECTANTS. Iodine. — The disinfecting power of iodine has been determined by Dr. G. M. Sternberg (American yournal of the Medical Sciences, April, 1S83) . He experimented upon the micrococci of pus and of septicaemia, bacterium termo, and the organisms found in broken-down beef tea. An exposure of two hours to the disinfectant in solution, in the proportion of 1 in 500, was effective in destroying the vitality of all of these organisms. Salmon (Report of United States Department of Agriculture* 1883) experimented on the micrococcus of fowl cholera, and found iodine an efficient disinfectant in the proportion of 1 part in 1,000. A solution of iodine in water (strength not given) was found by Koch 1 to destroy the spores of B. anthracis after twenty-four hours' exposure. Summing up briefly our knowledge upon this subject, the following conclusions seem to be justified : 1. Chlorine is an efficient disinfectant when present in the proportion of 1 part in 100, provided the air and the objects to be disinfected are in a moist state, and the exposure continues for upwards of one hour. 2. Chlorine, when used in sufficient concentration to act as a trust- worthy disinfectant, injures colored fabrics and wearing apparel. 3. Bromine is an efficient disinfectant in the proportion of 1 part in 500, provided the air be in a moist state, and the exposure continues for upwards of three hours. 4. Iodine, in solution, is an efficient disinfectant in the proportion of 1 part in 500, the exposure continuing for two hours. 5. The use of chlorine, and in a greater degree of bromine, requires considerable experience in management. When carelessly handled they may cause inconvenient or even dangerous symptoms in persons using them. For these reasons they are not suitable as disinfectants for pop- ular use. CARBOLIC ACID. BY CHARLES SMART. Carbolic acid may be said to have been recognized as an antiseptic from the time of its discovery by Runge, in 1834, in the distillate from coal-tar. This is sufficiently attested by the analogies which led to the use of the name coal-tar creosote, and the well known preservative action of the product from wood. In Watt's Chemical Dictionary we are informed, concerning the properties of carbolic acid, that "fish and leeches die when immersed in the aqueous solution, and their bodies subsequently dry up on exposure to the air without putrefying." The deodorant action of the acid was recognized as due not to a destruction of the offensive products of putrefaction, as in the case of some chem- icals, but to an influence on the process which gave rise to them. When this process was shown to be dependent on the development, growth, and multiplication of certain bacterial forms, a destruction of their germs, 1 Loc. cit. h'EPOKT OF COMMITTEE ON DISINFECTANTS. 2J or at least an interference with the conditions congenial to their growth* was of necessity assumed. On this, Prof. Lister, in 1867, based the use of the acid in antiseptic surgery. The success attending his method of treatment spread the fame of carbolic acid, and its known and well proved antiseptic properties led to its investure with disinfectant properties which were by no means proved. It was used largely as a disinfectant in Europe, and for several years was held in a similar high repute in this country. The first experiments to test its value failed to distinguish between the antiseptic and the disinfectant properties. As late as 1870, Grace Cal- vert's experiments 1 had a reference only to the delay in the exhalation of putrefactive odors from organic substances. Albumen and flour paste, which became offensive in five and seven days respectively when exposed to the air, were preserved for eleven and twenty-five days when mixed with five per cent, of the acid. Even the experiments of Shroeter, 2 in 1878, seem mainly directed to define an antiseptic value. A liquid, char- acterized only as teeming with bacteria, had its contained organisms ren- dered motionless and precipitated by the addition of .05 per cent, of the acid — a dilution of 1 : 2000. Raw flesh in a dilution of 1 : 10, 000=. 01 per cent., began to putrefy at the end of six days; in 1 : 2000=1.05 per cent., the liquid, notwithstanding the presence of the flesh, remained clear and without odor for four weeks; in 1 :ioooz=:.i per cent., the preservation was prolonged from six to eight weeks; while in 1 1500= .2 per cent, the liquid remained clear and free from all organisms for many months. Hence, he considered that a solution containing .1 per cent, of the acid is one in which no low organisms can exist, and that a dilution of .01 per cent, will retard their development for some time. The acid was recognized as being specially destructive to the moulds, a much smaller quantity sufficing to destroy them than was requisite to insure protection from the bacteria of putrefaction. Thus, Baxter 8 quotes Manassein as authority for the statement that one sixteenth of one per cent, deprived the spores of penicillium of their germinating power ; and Schroeter found that the vapor of the acid arrested the development of penicillium and mucor, and destroyed their spores. One thorough fumi- gation ot a mould-infected chamber acted so radically that for six weeks afterwards no trace of the fungi was discovered. It became evident, however, to the experimenters having this matter in view, that the acid might interfere with the development of the bac- teria of putrefaction without destroying their power of multiplication when transferred to a more congenial environment. Hence, culture experiments were instituted on the bacteria that had been subjected to the influence of the acid. Moreover, it was recognized that experiments on the bacteria of putrefaction were by no means satisfactory as argu- 1 Chemical News, London, 1870, vol. xxiii, p. 281. »" Beitrage zur Biologie der Pflanzen," Breslau, 187S, 3 Heft, S. 30 et seq. 8 " Report of the Medical Officers of the Privy Council and Local Gov't Board." London, 1875. P. 216, et seq. 28 REPORT OF COMMITTEE ON DISINFECTANTS. ments on the vitality of the disease germs which were concerned in the process of disinfection. Hence were instituted experiments on certain infective matters. Braidwood and Vacher investigated the action of the acid on vaccine lymph in 1S70, and verified their results in 1876. 1 On four children vaccinated with lymph containing 2.5 per cent, of acid, six vesicles were obtained at ten points of insertion. In these instances the lymph was removed from the arm, mixed in a watch-glass with the acid, and applied at once. A second group of children, five in number, were vaccinated in a similar way ; but the mixtures used had been preserved in Hus- band's capillary tubes for seventeen days, three weeks, four weeks, and six weeks respectively. These inoculations all failed, and the children afterwards underwent a successful normal vaccination. Similar results were obtained by trying the carbolated lymph on a heifer. Meanwhile, Dougall, in 1S73, operated on vaccine lymph, making use of subsequent vaccination as the test of the action of the carbolic acid on the virus. He exposed the lymph in a bell jar of one cubic foot capacity for thirty-six hours, and after mixing it with glycerine and water, sealed it up in capillary tubes until used for vaccination. The lymph thus treated produced satisfactory vesicles. Led by this result, he then treat- ed fresh vaccine with one per cent, of pure carbolic acid, and found its infective property undiminished. But about the same time Hoppe Sey- ler 2 determined that two per cent, of the acid destroyed the activity of vaccine virus ; and two years later, Baxter, in his careful work for the British health authorities, was also successful in destroying the virus, as proved by subsequent inoculation with the disinfected matter. He ex- posed dry vaccine to carbolic acid vapor in a bottle one third filled with the acid, and found that when the period of exposure was less than thirty minutes the infection was but slightly if at all impaired. When the ex- posure extended to thirty minutes, disinfection was effected in one speci- men, while another produced two vesicles for three insertions. In two instances, in which the exposure was prolonged for sixty minutes, the virus proved inefficient when subsequently used. He also found that while the presence of one per cent, of carbolic acid in liquid vaccine exerted no influence on its activity, two per cent, destroyed its infective power with certainty. Dougall, returning to this subject in 1879, 3 concluded from some of his experiments that if the vaccine were used immediately after its exposure to the carbolic acid, or if hermetically sealed in the meantime, the virus would fail, but that if exposed to the air after being carbolized it would recover its activity. Thus sixty parts of vaccine and forty of acid, when used immediately after mixture, gave no results, but when used after a free exposure to the air during fourteen days, it was found to have re- covered its active properties. He therefore concluded that the infected lu British Med. Association. Scientific Reports." London, 1876. *Arch. Gen., May, 1863, p. 633. s British Med. Jour., 1S79, vol. ii, p. 726. REPORT OF COMMITTEE ON DISINFECTANTS. 29 particles of the lymph became covered with coagulated albumen of the vaccine liquid, and that in vaccination the free acid coagulated the con- tents of the dermal capillaries and rendered absorption impossible. But these experiments of Dr. Dougall did not succeed in the hands of J. W. Miller, of Dundee. 1 He prepared four specimens, each containing two parts of carbolic acid and three of vaccine. The mixtures were exposed to the air for fourteen days before use ; and in each of the four experiments the lymph was barren. Two experiments were made with vaccine which had been exposed to the air for fourteen days after its admixture with five per cent, of the acid ; in one of these the lymph was barren, in the other an im- perfect vesicle was obtained. One experiment, however, appeared to verify Dr. Dougall's results : equal parts of vaccine and glycerine of car- bolic acid, after exposure to the air during fourteen days, yielded a good vesicle. But Miller was inclined to view this result with suspicion, and attributed it to pure lymph rubbed off by inadvertence from some of the other points of insertion on the child's arm. But other liquids containing germs or infective matter were used by the investigators. Rosenbach, 2 in 1873, injected dogs and rabbits with unhealthy pus, to which five per cent, of the acid had been added, the general tenor of his results showing that disinfection had been accom- plished. Baxter, two years later, experimented with the virus derived from the peritoneal cavity of guinea-pigs that had succumbed to infective peritonitis. The length of time during which the virus was exposed to the action of the acid varied from thirty minutes to three hours, thorough admixture having been effected in the meantime. In one set of experi- ments, two per cent, and one per cent, of the acid destroyed the infec- tion, as the animals inoculated with the mixture did not suffer. In a sec- ond series of experiments, one per cent, was efficient for protection, but with a virus containing only .5 per cent, the animal died in forty hours from acute cellulitis. In a third series, one per cent, was efficient, but death occurred with .5 per cent, in eighteen hours. In the fourth series, one per cent, proved again protective against the infective mate- rial. Similar inoculation experiments with the virus of glanders showed that two per cent, of carbolic acid destroyed its infection, while .5 per cent, failed to act as a disinfectant. By culture experiments, Sternberg, in 18S3, 8 showed that the micro- coccus of pus has its vitality destroyed so that it fails to develop when introduced into a sterilized bouillon after an admixture of two hours with .8 per cent, of the acid, while with .5 per cent, its subsequent cultiva- tion was successful ; and that the micrococcus of septicaemia is destroyed by .5, but not by .25 per cent. This defines the germicide limits of the acid in respect to these organisms. On the other hand, when car- bolic acid was added to the sterilized culture-liquid, a much smaller per- 1 Med. Record, Sept., 1873, p. 427. ^Practitioner, Sept., 1884, p. 146. *Amer. Jour. Med. Sciences, April, 1883. 30 REPORT OF COMMITTEE ON DISINFECTANTS. centage than was needful for a germicidal action sufficed to prevent the development of the micrococci of pus and of septicaemia when implanted for cultivation. Thus, .2 per cent, prevented the development of the organisms, while .1 per cent, failed to protect the culture-liquid from its attack. Similar results were obtained with the micrococcus of septi- caemia. This defines the antiseptic limits of the acid in respect to these •organisms. Baxter was of opinion that the length of time during which the acid was permitted to act upon the infective material was of no importance, pro- vided that thorough mixture was insured. This implies a belief in the in- stantaneous action of the acid on the active principle of the virus. Some experiments by Koch 1 in 1SS1, Salmon 2 in 1883, and Schill and Fischer 3 in 1S84, indicate that time of exposure, as well as strength of solution, •enters as an element into the question of disinfection. Thus, the last mentioned investigators, operating on fresh tubercular sputa, found that disinfection was accomplished by treatment with three, two, or even one per cent, of acid for twenty hours ; but that five per cent, failed to dis- infect when the period of digestion was limited to two hours. Post- mortem examinations discovered sound organs in the animals inoculated with the former mixtures, and tubercular disease in those of the speci- mens treated with the latter and stronger mixture. Salmon, operating on the micrococcus of fowl cholera, obtained the destruction of the virus by one per cent, of the acid, the test being inoculation. In some experi- ments, in which the test was cultivation, one per cent, succeeded, and .5 per cent, failed to destroy the power of germination when the digestion with the acid was continued for one and a half hours ; but. 5 per cent, was successful w r hen the digestion was prolonged for twenty-four hours. The bacilli and spores of anthrax have been subjected to a number of experiments, of which those of Davaine 4 are the earliest. The blood ot an infected animal, diluted with one hundred parts of water, was used. This was found to be speedily fatal to guinea-pigs when injected under the skin, but its virulence was destroyed on treatment for an hour with one per cent, of carbolic acid. Koch found that the spores of anthrax had their vitality destroyed by immersion for twenty-four hours in a five per cent, aqueous solution of the acid. A two per cent, solution was not efficacious ; but after five days' digestion in this solution the development of the spores was somewhat retarded. Further experiments showed entire failure of disinfection with a one and two per cent, solution ; suc- cess after seven days with three per cent. ; after three days with four per cent, and after two days with a five per cent, solution. Culture in gela- tine was the test employed in these instances. On the other hand, the bacilli wexe destroyed by exposure of from two to twenty-five minutes in .aqueous solutions containing from five to one per cent, of the acid, the J "Mitt. a. d. Kais. Gesundheitsamte," 1 881, vol. I. 2 " Report Dept. Agriculture, U. S." 1883. s "Mitt. a. d. Kais. Gesundheitsamte," 1883, vol. ii. iComptes Rendus, Oct. 13, 1873. REPORT OF COMMITTEE ON DISINFECTANTS. 3 1 test being culture in solidified blood-serum. The culture in gelatine of the anthrax spores was not prevented by their antecedent immersion for one hundred and ten days in oil containing five per cent, of the acid, nor by seventy days in alcohol of the same carbolic strength. An oleaginous five per cent, solution diminished the development of the bacilli in three or four days, and accomplished disinfection on the sixth day, as shown by the failure of subsequent efforts at cultivation. Even a one per cent, solution in oil destroyed their power of development on the sixth day, but it is to be observed that a similar result followed the use of pure olive oil. Arloing, Cornevin, and Thomas 1 found that the virulence of anthrax spores persisted after an immersion of forty-eight hours in alcohol con- taining two per cent, of the acid, while it was destroyed by the action of the same percentage in water. Blyth 2 also experimented with these spores. He showed the inefficiency of the carbolic acid powders — Cal- vert's, Jeyes's, and McDougall's. The spores invariably developed not- withstanding contact with the powder for twenty-four hours. A one per cent, carbolic solution had no effect on their development ; five per cent, retarded their growth ; twenty-five per cent, in alcohol rendered them incapable of germinating in broth. While these investigators were testing the power of carbolic acid on certain disease-producing substances, many series of experiments were performed on the bacteria of putrefaction, with a view of determining the germicidal as well as the antiseptic powers of the acid on the organ- isms, the latter being expressed by the quantity of acid required to be added to a nutritive liquid in order to restrain their growth, and the for- mer to prevent them from multiplying when subsequently transferred to a suitable culture-liquid. Baxter's experiments showed that .5 and .1 per cent, were required for the germicidal action, the larger percentage being requisite when the liquid was albuminous. Hamlet, 8 operating on Pasteur's liquid contain- ing B.punctum, B. tcrmo, and M. crepusculum, found a slight diminu- tion in the number of moving bacteria after standing five days mixed with one per cent, of carbolic acid, while with five per cent, few of the bacteria showed signs of movement. Nevertheless, in this last experi- ment their vitality persisted, for when a little of the solution was trans- ferred to a large quantity of Pasteur's liquid, the whole was in two days teeming with bacteria. Notter's 4 results were to the effect that 3.3, 5, and 6 per cent, of carbolic acid did not destroy the movements of the bacteria in a putrid infusion of beef, even after the lapse of seven days. Jalan de la Croix 5 found that when two drops of a liquid teeming witn bacteria are added to a sterilized meat-juice, the acid must be present in the proportion 1 :66o, to prevent development; but to produce a germi- ^Comptes Rendus Soc. de Biolog. Septieme serie, t. iv. ^Medical Times and Gazette, Oct. 11, 1884, p. 498. z Jour. CJiem. Soc, London, 1881, xxxix, p. 326. ^Dublin Jour. Med. Sciences, 1879, vol. 68, p. 196. 5 "Arch, fuer Experimentelle Pathologic" Leipzig, 1881, p. 175, et. sea. 32 REPORT OF COMMITTEE ON DISINFECTANTS. cidal effect in this weak bacterial liquid, acid in the proportion i :22 had to be added. The bacteria in broken-down meat infusion were killed by immersion for twenty-four hours in a solution of i : 22, although not in 1 .-42 ; but to prevent the development of germs when this liquid was introduced into a sterilized infusion, it was necessary to give them a preparatory soaking for twenty-four hours in an acid of the strength 1 :2.66, for a solution of 1 :\ did not deprive them of their fecundity. To prevent the decomposition of boiled meat-juice by germs falling into it from the air, 1 1402 was required; but for an unboiled infusion 1 1502 sufficed ; and to prevent the development of the germs in the former when transferred to a sterilized liquid, 1 :22 was required, while those in the latter were not deprived of their germinating power by 1:10. Vallin 1 justly remarks of De la Croix's experiments, that they must be accepted with some reserve, since it is contrary to the general experience that a boiled liquid should require more of an antiseptic to preserve it than one which had not been boiled. Sternberg found that .2 per cent, was antiseptic in view of B. termo, but one per cent, was required for action as a germicide. He further found that the bacteria in broken- down beef tea retained their vitality after an exposure of two hours to a four per cent, solution. Turning from these experiments in which the carbolic acid was used in the form of liquid to those in which its vapor was employed, we find the following, in addition to those already mentioned in connection with antiseptics, the destruction of moulds, and of the vaccine efficiency. Perrin and Marty 2 failed to prevent the decomposition of barley-water, milk, blood, urine, etc., by the atomization of a five per cent, carbolic liquid. Schotte and Gartner 3 volatilized carbolic acid by heat in a closed chamber in which were exposed to the action of the vapor liquids con- taining bacteria and woollen cloths that had been dipped in these liquids, determining at the close of the exposure whether the fecundity ot the bac- teria had survived by transferring them to a sterilized culture-liquid. For efficient disinfection, rapid evolution of the carbolic vapors was required. The bacteria in the exposed liquids were destroyed by the diffusion of 7.5 grammes of carbolic acid per cubic metre, but those in the impreg- nated cloths required a stronger diffusion, 12.5 grammes, when the fab- rics were damp, and 15 grammes when they were dry. From a survey of these experiments on carbolic acid, performed since the introduction of methods of precision in testing germicidal or disin- fectant properties, the value of the acid in these respects may be deter- mined. One per cent, in an aqueous solution has destroyed with certainty the virulence of septic and purulent matters, of the tubercle bacillus, and of the micrococci of fowl cholera ; some of the organisms related to putre- faction have also been destroyed by solutions of this strength. But to lu Traite des Disinfectants etde la Disinfection." Paris, 18S2, p. 163. 1 " Bulletin de la Soc. de Chir.," 1879, *• v -> P- l S3- '"Deutscher Verein fur Oeffentliche Gesundhpflege," 1880, t. xii, p. 337, et seq. REPORT OF COMMITTEE ON DISINFECTANTS. 33 produce these results, in some instances, the contact with the disinfectant had to be continued for many hours. Two per cent, of the acid in an aqueous solution was required to destroy the infection of vaccine and glanders ; but some of the experiments on the former seem to indicate that no destruction of the virus was effected, but merely a suspension of its powers, which were recovered on the dissipation of the acid by subse- quent prolonged exposure to the air. The spores of anthrax did not lose their ability to germinate unless treated with a five per cent, solution for twenty-four hours, or with a weaker solution for a longer time. Lastly, as showing how little reliance can be placed on carbolic acid as a disin- fectant, except in special instances, as in those above mentioned where its effects have been determined, the organisms in broken-down beef tea were not deprived of their reproductive powers by treatment with four per cent, acid, Sternberg, nor with six per cent., Notter, nor with ten per cent., De la Croix; — the last observer, indeed, asserts that about thirty per cent, (i : 2.66) was needful to effect this object. The large percentage of the acid required for disinfectant or germicidal action when applied directly in the liquid form, prepares us for its failure when used in the form of vapor. Douglas and Baxter, from the results of their experiments on vaccine, concluded that aerial disinfection by car- bolic acid vapor was practically impossible. The atomizer, however, offered better facilities for the diffusion of the vapor ; and Strott 1 in 1876, and Wernich 2 in 1883, recommended the use of the spray as protective against albuminoid contagious principles. But the experiments of Per- rin and Marty, and of Schotte and Gartner, demonstrated its inutility as against bacterial life. The valuable antiseptic properties of the acid do not come within the scope of this article, although they have been in a measure indicated incidentally. DISINFECTION WITH MINERAL ACIDS. BY VICTOR C VAUGHAN. Disinfection with mineral acids in one form or another has long been practised. Sulphurous acid was used by the ancient Greeks in the puri- fication of their temples after sacrificial offerings had been made. In 1773 Morveau recommended the vapor of hydrochloric acid, produced by the action of sulphuric acid on sodium chloride. In 1780 Smyth began the use of nitrous acid vapor as a disinfectant. During the present cen- tury, many experiments have been made for the purpose of determining the value of the mineral acids as disinfectants, both in liquid and in vapor form. It is the purpose of this paper to review briefly these reports, and to ascertain what conclusions may be drawn therefrom. Since sulphu- 1 " Ventilation und Desinfection der Wohnraume," Hoitzminden, 1876, p. 19. •*' Real-Encyclopadie der Gesammten," Heilkunde, 1883, B. 15, S. 170, et seq. 34 REPORT OF COMMITTEE ON DISINFECTANTS. rous acid will be discussed in another paper, no further mention will be made of it here. 1 Hydrochloric Acid. Dougall 2 found that vaccine virus, exposed under a bell-jar of a cubic foot capacity, for twenty-four hours, to the vapor of the acid, became inert. After exposure, the lymph was mixed with glycerine and water, and the reaction of the mixture (acid) was noted. The mixture was then hermetically sealed in tubes, and so kept until used. Dr. Dougall believed that the effectiveness of the vapor was due to its rendering the virus acid. In proof of this he gives the following tabular statement of the reaction of the lymph and glycerine mixture used in his successful and unsuccessful vaccinations after exposure to different agents : Successful vaccina- Reaction of the Vaccination not Reaction of the tion. Virus not lymph and glycerine successful. Virus lymph and glycerine destroyed. mixture. destroyed. mixture. Carbolic acid vapor. Nutral. Chloride of lime. Acid. Carbolic acid. u Sulphurous acid. « Chloroform. Alkaline. Nitrous acid. « Camphor. « Glacial acetic acid. <« Sulphuric ether. «« Hydrochloric acid. u Iodine. Neutral. Commenting upon the above table, Dr. Dougall states, — "These results per se are singularly and suggestively explicit. They show that the mixture of lymph and glycerine of the successful vaccinations was either neutral or alkaline ; while that of the unsuccessful was, without excep- tion, acid. Hence, volatile acids, or a volatile body causing acidity by chemical affinity, as the chlorine from the chloride of lime, which pro- duces hypochloric acid and free oxygen, are the best destructives of the active properties of vaccine lymph, and therefore a priori of variolous matter and other zymotica. 8 The same theory is insisted upon by Dr. Dougall in a later paper. 4 Results with hydrochloric acid vapor, similar to those obtained by Dougall, were reached by Braidwood and Vacher in eight experiments. 5 Koch 6 ascertained by cultivation that anthrax spores were destroyed 1 See papers by Drs. Sternberg and Raymond in this series of reports. 2 "Glasgow Medical Journal," vol. 5, p. 166. 3 Loc. cit., p. 168. 4 " British Med. Journ.," voi. ii, p. 726, 1879. «Life History of Contagium. « Mittheilungen a. d. Kais. Gesundheitsamte, B. I. S. 263. REPORT OF COMMITTEE ON DISINFECTANTS. 35 after ten days' exposure to a 2 per cent, solution of the acid ; but that ex- posure from one to five days failed to destroy the spores. Dr. Sternberg, in some experiments made for this report, found hydro- chloric acid to fail as a disinfectant when used in 10 per cent, solution, and to be successful when the strength was increased to 15 per cent. Each c. c. of the acid used by Dr. Sternberg contained .395 gramme of HC1. Sulphuric Acid. Koch 1 noticed diminished development of anthrax spores after exposure to a 1 per cent, solution of sulphuric acid for twenty days. The test was by cultivation. Salmon, 2 experimenting upon the micrococcus of fowl cholera, fjund one half per cent, solution of sulphu- ric acid successful as a disinfectant, tested by inoculation ; but one fourth and one eighth per cent, solutions unsuccessful, tested by cultivation. Sternberg 8 states that " sulphuric acid destroys B. termo and the two species of micrococcus experimented upon in the proportion of 1 : 200; but a 4 per cent, solution failed to destroy the bacteria in broken-down beef tea (old stock) , doubtless because of the presence of reproductive spores. The multiplication of the bacteria mentioned was prevented by the presence of this acid in a culture solution of 1 : 800. Dr. Sternberg has given the per cent, of sulphuric acid necessary to insure disinfection at 8. Each c. c. of the acid used contained 1.480 gramme H 2 S0 4 . Nitrous Acid. Dougall 4 found that vaccine lymph, exposed to nitrous acid under a bell-jar of one cubic, foot capacity for twenty-four hours, was rendered inert. The lymph was treated as given under hypochloric acid, and the action was supposed to be due to rendering the lymph acid. Notter 5 has experimented upon nitrous' acid as an aerial disinfectant. However, his conclusions are not wholly trustworthy, as he considered the bacteria destroyed, when their motion was only arrested. He says, — " I believe the full effect of the agent to be produced when there is arrest of motion, with complete precipitation and disorganization of the bacteria, and I have endeavored in each case to look for this result. One hundred c. c. of putrid beef infusion in saucers *were placed in a chamber, of a cubic capacity of fifty-three feet, with two ounces of copper wire, and fifty c. c. of concentrated nitric acid, yielding .35 per cent, of nitrous acid. Soon the bacteria became less active, and in forty-eight hours the activity was still further diminished, and a heavy precipitation of the or- ganisms was noticed. The infusion was free from odor. On the third day there was no tendency to the further development of the bacteria, and' the liquid was quite inodorous. At the end of a week there was no further decomposition, and the infusion was found to be strongly acid. Sternberg 6 found that exposure of vaccine virus for six hours to an atmosphere containing 1 per cent, of nitrous acid vapor destroyed the 1 Loc. cit, p. 264. 2 Report Dept. Agriculture, 1883. 8 Bacteria, p. 223. * Loc. cit. B " Dublin Journal Med. Sciences," vol. 71, p. 508. •National Board of Health Bulletin, p. 2S7. 36 REPORT OF COMMITTEE ON DISINFECTANTS. germs ; also, that the bacteria of putrid urine was destroyed when exposed on filter paper for six hours to an atmosphere containing one half per cent, of nitrous acid gas. Nitric Acid. Dr. Sternberg has ascertained that nitric acid fails as a disinfectant in solutions of 5 per cent., but is effectual in solutions of 8 per cent. Each c. c. of the acid used contained .819 gramme of HNO3. Chromic Acid. Koch 1 ascertained thatunthrax spores were destroyed by exposure to 1 per cent, solutions of chromi: acid after from one to two days. Osmic Acid. Koch 2 found, by cultivation, that anthrax spores were destroyed by exposure for twenty-four hours to 1 per cent, of osmic acid. Practical Considerations of the Use of the Mineral Acids as Disin- fectants. The action of 10 and 5 per cent, solutions of sulphuric, nitric, and hydrochloric acids upon lead pipes was tried, with the results given in the accompanying table. Weighed pieces of lead pipe were placed in the dilute acids, and the loss was determined by subsequent weighings. This represents a more powerful action than would result simply from the rapid passage of the disinfectant through the pipes ; but the table gives results which would be obtained by the solution standing in a trap. At the time of each weighing, the dilute acid was replaced by a fresh portion. The experiments were continued until the nitric acid had completely destroyed the pipe ; but as the results are sufficiently shown by the follow- ing figures, it is unnecessary to give the table in full. After a number of days there was a slight increase in the weight of the pipes placed in the sulphuric acid solutions. All the acids used were of the commercial grade. We also have figures showing the action of the dilute acids upon iron pipes ; but, as this action is rapidly destructive with all the acids, it is unnecessary to give the figures. In order of disintegrating effects upon iron pipes, sulphuric acid acts with most vigor ; while there is not much difference in the effects produced by the same strength solutions of nitric and hydrochloric acids. The action upon zinc is in the same order as that given for iron ; while the solvent action of nitric acid on tin was found to be greater than that of either sulphuric or hydrochloric acid. 1 Loc. cit., S. 264. 2 Loc. cit. REPORT OF COMMITTEE ON DISINFECTANTS. 37 ^ *J ^ *1 L^ p tf p. 1 p CD a> <^ o p y- cr O* cr p o a\ *> O0 JO OJ p P. o o ■ C 3* n- p a 1 s ~ 00 Ln OKI o Cfq' ET. OX) ° P 3 & £ ^ P to « ►H Oo o o* ° -. o 3 >-* Ln t_n Ln Ln Ln a o tO 10 O) 10 OO to Oo to Co 10 3 3 n o O O O O 7) ft - 2 8 8 8 8 o p 3 r o c Ln ui Ln Ln Ln O 8,3 12 * Ln IJ 10 to vb to vb 10 vb O o p 5 H <"T> O ffi o M 8 8 8 8 p 3 u o 09 c Oj -£. -u -*>. Ln O Z3 o ■u A 00 Oj *■« Ln M to Ln p 3 M -o 2. a o to O tJ to O 8 8 9 3^ ft ON Oo 4^ -f>. r Mh 1 to O Ln 8 p 3 o 09 2 O 4*- 4^ 4>. Ln Ln o *3 Ln 4 Oo vO OJ Oj Oo b p •a 2. 8 Ln s 8 o o K O £ o 2 j* 10 M - M o M m O Ln bo 00 o 8 p 3 b r 2J C Ln Ln Ln Ln Ln O S.^ o 10 CO 10 bo to vb to vb OJ p 3 X3 2 2 3T Ln 8^ 8 Oo o g !? o o o o o C p r b b b b p o HH -p» O0 ^i 3 C/l Ol o o o u n w Ln Ln o Ln to vb Ln Ln Oj b C. p £>3 ■e 2. Ln 2 O 10 o 1 8 3 C/3 2 £f o ft o O b O b o b o b p 3 o X o -u to n Ln Ln o o w ■^ 38 REPORT OF COMMITTEE ON DISINFECTANTS. THE METALLIC SULPHATES. BY GEORGE M. STERNBERG. The metallic sulphates have been largely recommended as "disinfect- ants," and directions for their use are to be found in the printed circulars of health authorities in this country and in Europe. In France the sul- phate of copper is a favorite disinfectant, and, as I shall shortly show, is a reliable agent for the destruction of germs in the absence of spores. It is very much superior to ferric sulphate or zinc sulphate, which have been more extensively used in our own country. The value of all these agents as antiseptics is beyond question ; and when the object in view is to prevent the development of germs in privy- vaults, cess-pools, etc., a solution of "copperas," on account of its cheap- ness and efficiency, is especially to be recommended. But the directions often given for the use of dilute solutions of ferric sulphate or zinc sul- phate, for the disinfection of the sputa of patients with diphtheria, the excreta of patients with cholera, typhoid fever, etc., are founded upon a mistaken estimate of the germicide power of these salts. The metallic sulphates have all a certain value for the prevention of putrefactive fermentation, and for neutralization of the volatile products of putrefaction. They are therefore "disinfectants" in the popular ac- ceptation of the term. Thus Vallin says, — Metallic Sulphates in general. — These agents are disinfectants in the vulgar sense of the word. They diminish or cause to disappear bad odors, their action being limited to the neutralization of ammonia and the decomposition of sulphuretted hydrogen, or of the sulph-hydrate of ammonia. In this group are the soluble salts of iron, of zinc, of copper, of manganese, and of lead. The oxides of these metals, which are quite cheap, have also been recommended for this purpose, but the salts have the advantage over the oxides of being able to sat- urate ammonia already formed, or that which results from the decomposition of the sulph-hydrate of ammonia. The oxide of iron, for example, can only fix sulphuretted hydrogen by forming the sulphuret of iron. The sulphate of iron produces in addition the sulphate of ammonia. These salts, then, cannot neutralize all bad odors, and therefore they do not entirely merit the title of deodorants. Bad odors, indeed, owe their infection to a great quantity of diverse substances which have not been completely determined by chemistry, and of which scatol is one of the most recently discovered. It is, then, almost entirely the two badly smelling compounds which have been longest known, which are neutralized by these metallic salts. 1 Virchow has pointed out one of the objections to the use of the sulphate of iron for disinfecting feces. The volatile fat acids, butyric, valerianic, etc., which have a disgust- ing odor and are highly toxic, are ordinarily combined with ammonia. When we throw sulphate of iron upon fecal matter, the sulphuric acid combines with the ammonia, and fetid products are given off, which are very volatile. The immediate effect, therefore, of throwing sulphate of iron into latrines is frequently to augment the bad odor, which, however, soon diminishes, but ordinarily reappears after some time. 2 In what follows we shall endeavor to fix the value of the metallic sul- phates as disinfectants, in accordance with the definition of the term x Traite des Disinfectants, p. 57. J Op. cit, p. 63. REPORT OF COMMITTEE ON DISINFECTANTS. 39 heretofore given by the Committee on Disinfectants, i. e., the germicide value as fixed by biological tests. Ferric Sulphate. — In the writer's experiments, published in the Amer- ican Journal of the Medical Sciences (April, 1883), it was found that a saturated solution of ferric sulphate failed to destroy the growing power of any of the test organisms, the time of exposure being two hours. A recent experiment upon a micrococcus obtained from the pus of an acute abscess gave a similar result. The organism grew freely in culture solutions after exposure for two hours to a 10 per cent, solution. According to Arloing, Cornevin, and Thomas, exposure to a 20 per cent, solution for forty-eight hours does not destroy the virus of symp- tomatic anthrax. The vitality of anthrax spores is not destroyed by ex- posure for six days in a 5 per cent, solution (Koch). 1 Zinc Sulphate. — In the writer's experiments, reported in the Amer- ican Journal of the Medical Sciences (1. c), a solution of 20 per cent, of this salt failed to destroy the micrococcus of pus. In experiments re- cently made, the same micrococcus grew after exposure to a 10 per cent, solution for the same time (two hours), but development was somewhat retarded. Another micrococcus ( M. tetragenus) was destroyed by a 10 per cent, solution in the same time. Broken-down beef tea, mixed in equal quantities with a 40 per cent, solution, was not sterilized at the end of two hours, as shown by culture experiments made in the usual way. Koch found (1. c.) that a 5 per cent, solution had not destroyed the growing joower of anthrax spores at the end of ten days, although their development was somewhat retarded. Cupric Sulphate. — I have recently made experiments with this salt upon pure cultures of B. anthracis and of B. sudtilis, and find that in a 20 per cent, solution (equal parts of a 40 per cent, solution and of the culture) it fails to destroy the vitality of the spores of these bacilli in two hours' time. Arloing, Cornevin, and Thomas found that the dried virus of symp- tomatic anthrax is destroyed in forty-eight hours by a solution of this strength (20 per cent.). Koch found (1. c.) that a 5 per cent, solution did not destroy the vitality of anthrax spores at the end often days, al- though the rapidity of development was somewhat retarded. The germicide power of this salt is, however, decidedly superior to that of the corresponding salt of iron or of zinc. I have demonstrated by recent experiments that it destroys micrococci in the proportion of .5 per cent. (= 1 : 200). The experiments were made upon a micrococ- cus derived from the pus of an acute abscess, and upon the micrococcus of swine plague. In one half the amount named (1 : 400) it failed to destroy the vitality of these micrococci. This agent, then, is a valuable germicide, and may be safely recom- mended for the disinfection of material not containing spores. But none ^ee table on p. 264 of the first volume of the " Mittheilungen aus dem Kaiserlichen Gesundheit- samte." 40 REPORT OF COMMITTEE ON DISINFECTANTS. of the metallic sulphates can be relied upon for the destruction of spore- bearing pathogenic organisms, and the germicidal power of ferric and zinc sulphate is too feeble to make these salts available for disinfecting purposes, even in the absence of spores. ZINC CHLORIDE. In his classical essay on disinfection, 1 Koch expresses astonishment that an agent, which proved almost entirely inefficient as a germicide in his experiments, should have obtained the widespread reputation as a disinfectant which chloride of zinc enjoys. He shows that anthrax spores, exposed to the action of a five per cent, solution ( i : 20) of this salt for thirty days, germinated as freely upon a suitable culture medium as similar material not so exposed. The development of micrococcus pro- digiosus was only slightly retarded by exposure for upwards of sixteen hours to a one per cent. (1 : 100) solution. Anthrax spores developed freely in a one tenth per cent. (1 : 1000) solution of this salt. Mr. A. W. Blyth 2 says a one per cent. (1 : 100) solution seemed to stimulate the growth of anthrax spores; five per cent. (1 : 20) failed to destroy their vitality ; while twenty-five per cent. (1:4) seemed to arrest the life of the spores. Dr. Sternberg 3 found two per cent. (1 : 50) destructive to the micro- coccus of gonorrhoeal pus, while one half per cent. (1 : 200) destroyed the power of development of the septic micrococcus. In Sternberg's later experiments 4 ten per cent, of Squibb's liquor zinci chloridi (said to contain fifty per cent, of anhydrous chloride of zinc) was found effective in destroying the organisms of broken-down beef tea. Numerous exper- iments have shown that these organisms are fully as resistant to most germicides as are the spores of B. anthracis. In order to clear up the apparent discrepancy between these observations of Koch and Sternberg, an additional series of experiments has recently been made by the latter, assisted by Dr. A. C. Abbott. These experiments showed that the spores of B. anthracis are not killed by an exposure for two hours to a ten per cent. (1 : 10) solution of this salt. A five per cent. (1 : 20) solu- tion, acting for the same period, was, however, effective in destroying the spores of B. subtilis, and upon broken-down beef-peptone solution, which had been freely exposed to the air, and consequently contained a variety of micro-organisms. A two and a half per cent, solution (1 : 40) failed to sterilize putrid beef-peptone solution. a Ueber Desinfection : Mittheilungen a. d. Kais. Gesundheitsamte. Bd. I. S. 261. ^Medical Times and Gazette, Oct. 11, 1883. s Am. Journ. Med. Sciences, April, 1883, p. 331. *T/ie Medical News, Feb. 7, 1885. REPORT OF COMMITTEE ON DISINFECTANTS. 4 1 The above experiments indicate that zinc chloride, in the proportion of five per cent, added to the material to be disinfected, can be relied upon for the destruction of micro-organisms in the absence of spores. To destroy the vitality of anthrax spores, however, a twenty per cent, solution is necessary. MERCURIC CHLORIDE. BY GEORGE M. STERNBERG. The use of corrosive sublimate as a parasiticide and as an antiseptic agent for the preservation of animal tissues, etc., has long been known, but the researches which have established its value as a disinfectant are of comparatively recent date. These researches, made during the past four or live years, have demonstrated that bi-chloride of mercury occu- pies a leading place among known germicide agents. Miquel places mercuric iodide above the chloride as an antiseptic, and it may be that it has a correspondingly greater germicide value. But from a practical point of view the chloride must still be accorded the first place on ac- count of its cheapness and solubility. My own observations are in accord with those of Koch, of Jalan de la Croix and others, as to the power of this agent in dilute solutions (r : 1,000 to 1 : 10,000) to destroy the spores of bacilli, — B. a7ithracis and B. subtilis, — and this constitutes the most difficult biological test known. Micrococci and bacilli in active growth, without spores, are killed by much weaker solutions (1 : 20,000 to 1 : 40,000). Klein, of London, is, so far as I know, the only author who has re- ported results in conflict with these. In his recent work on Micro- organisms and Disease? he says, — By sowing any micro-organism in a nourishing medium, to which has been added a cer- tain substance (e. £-., carbolic acid to the amount of one per cent.), and exposing this me- dium to the conditions of temperature, moisture, etc.. otherwise favorable to the growth of the organism, if we find after the lapse of a due period the growth is retarded or alto- gether inhibited, the conclusion is drawn that this substance (viz., the carbolic acid of 1 per cent.) is an antiseptic. There is nothing more fallacious than this mode of reason- ing. A great many micro-organisms can be exposed to a 1 per cent, solution of carbolic acid for hours without in the least being affected, for on being transferred to a suitable nourishing medium they grow and thrive well. Similarly, by placing the spores of B. anthracis in a proteid medium containing perchloride of mercury of the strength of 1 in 300,000, it is found (as Koch has shown) that the spores are absolutely incapable of ger- minating. But if from this the Conclusion is drawn that perchloride of mercury of the strength of 1 in 300,000 is a germicide, I should most strongly dissent, — for perchloride of rnercurv, even of the strength of 1 per cent., is not a germicide any more than vinegar; for on placing the spores of B. anthracis in a proteid medium, to which so much vinegar or any other acid has been added as makes it decidedly acid, it will be found that the spores do not germinate. 1 The Practitioner, Lond., Oct., 18S4, p. 251. 42 REPORT OF COMMITTEE OA DISINFECTANTS. I have recently had occasion to object to the use of the terms antisep- tic and germicide as synonymous, and the confusion resulting from such a misuse of the term antiseptic is exemplified in the above quotation. No one familiar with the present state of knowledge upon the subject would think of inferring that mercuric chloride is a germicide in the pro- portion of i : 300,000, because anthrax spores do not germinate in cul- ture-fluids containing this amount. But an agent which prevents the development of putrefactive bacilli is an antiseptic, for putrefactive de- composition is prevented by sQch an agent as well as by one which kills germs. A germicide is necessarily an antiseptic, but an antiseptic is not necessarily a germicide. Thus alcohol, chloride of sodium, borax, sul- phate of iron, and many other agents constantly used as antiseptics, do not in the most concentrated solutions destroy the vitality of the spores of bacilli, and consequently are not germicides. The statement made by Klein, that " perchloride of mercury even of the strength of 1 per cent, is not a germicide any more than vinegar," is opposed by the experimental evidence reported in detailhy Koch, and by my own extended experiments with this agent. I am convinced that there must have been some defect in Klein's method of working, and that the spores which killed his guinea-pigs had not been fairly exposed to the action of the disinfecting agent. He says, — I have tried the action of a number of substances in common use as antiseptics {e. £-., Calvert's fluid, pure terebene, phenol 10 per cent., perchloride of mercury 1 per cent.), on the spores of B. authracis, exposing these in comparatively large quantities to the above fluids (the two being well mixed) for twenty-four hours, and then inoculating guinea-pigs with them (spores and antiseptic). The animal died with symptoms of typical anthrax, the blood teeming with the B. authracis} The very definite evidence from various sources, a portion of which will be given below, as to the power of mercuric chloride to destroy the spores of anthrax in much weaker solutions than that used by Klein, and in a much shorter time, justifies the suspicion that these guinea-pigs died from accidental inoculation with spores not subjected to the action of the disinfectant. This suspicion is further justified by Klein's account of the frequent accidents of this kind which have occurred in his laboratory. Among other examples of this, given in the work already referred to, is the following : Another gentleman working in the laboratory of the Brown Institution intended to in- oculate several guinea-pigs with human tubercles. For this end he mashed up in a saline solution, in a clean mortar, a bit of human lung studded with tubercles. He did this in my room on the same table on which I was working with anthrax. One of these guinea- pigs, inoculated with human tubercle, died before the second day was over of typical anthrax. Its blood was teeming with the B. authracis. Such an accidental anthrax in guinea-pigs inoculated with tubercle occurred several times. * * * I myself had the following accidental contaminations : * * * 2 1 Op. cit., p. 253. 2 Micro-organisms and Disease. The Practitioner, London, Aug., 1884, p. no. h'EPORT OF COMMITTEE ON DISINFECTANTS. 43 We are not here directly concerned with the restraining influence of mercuric chloride upon the development of anthrax spores, but having- made some recent experiments in this direction which fully confirm the results previously reported by Koch, I may be excused for referring to the matter, especially in view of the therapeutic and sanitary possibilities which suggest themselves in connection with this inhibiting action of corrosive sublimate in very dilute solutions. From a sanitary point of view, it is evident that an agent which is capable of preventing the devel- opment of disease germs in cesspools and privy-vaults in the proportion of 1 : 300,000 (/'. e., one pound costing fifty cents would inhibit the devel- opment of anthrax spores in 300,000 pounds of a suitable culture-fluid) has an interest for health officers quite independent of the interest which attaches to it as a potent gemicide in stronger solutions. Experiment, Dccefnber 22, 1884. Mercuric chloride was added to a sterilized culture-fluid in the proportion of 1 : 100,000, 1 : 200,000, and 1 : 400,000, and two culture-flasks were filled from each solution. These flasks were then inoculated with anthrax spores from a pure culture, and another flask, not containing the mercuric chloride, was inoculated to test the stock. At the end of twenty-four hours the last mentioned flask contained an abundance of anthrax filaments : the others remained clear. At the end of fortv-eight hours the two flasks containing the bichloride in the proportion of 1 : 400,000 contained flocculi of anthrax filaments, and the others remained clear. Davaine found that the virulence of serum containing anthrax bacilli, obtained from the subcutaneous cellular tissue of an animal recently dead, is destroyed by adding to it corrosive sublimate in the proportion of 1 : 1 50, 000. x In this case no spores are present in the material. The restraining power of this agent is not so great for the spores of £. subtilis as for those of anthrax. This was shown by an experiment made upon the same date as that above reported. At the end of twenty-four hours after inoculation with spores, a mycoderma of B. subtilis had formed in solutions containing 1 : 100,000 ; and in forty-eight hours the same results had occurred in two flasks containing 1 : 50,000. The inhibiting power of this agent is still less for micro-organisms in active multiplication. Thus, in my experiments reported in the A?n. Journal of the Med. Sciences, April, 1883, the development of micro- cocci was prevented by 1 : 30,000 to 1 : 40,000. I have recently repeated these experiments with a similar result. To destroy the vitality of the same micrococci, as proved by their failure to grow in culture-fluids, re- quired 1 : 20,000, while the bacteria in broken-down beef tea containing spores were destroyed by 1 : 10,000. According to Koch, mercuric chlo- ride, in the proportion of 1 : 1,000, destroys all spores in a few minutes ; and in weaker solutions, up to 1 : 10,000, he has shown by culture and inoculation experiments that this agent destroys the vitality of anthrax spores. ■ "Recherches sur le traitemcnt des maladies charbonneuses chez l'homme." Bulletin de PAcad. de Med., 17 Juillet, 1SS0, p. 557. 44 REPORT OF COMMITTEE ON DISINFECTANTS. The results of his culture and inoculation experiments are not, how- ever, entirely in accord ; and it seems probable that failure to develop upon the surface of a solid culture-medium, after ten minutes' exposure to i : 20,000, may have been due to the restraining influence of a small amount of bichloride not removed by the washing in alcohol, which was resorted to for the purpose of getting rid of this complication. Fluid- cultures possess an evident superiority for such experiments as this ; for when a very small quantity of spore-containing material is introduced into flasks containing a large 'quantity of culture-fluid, the disinfecting agent is diluted beyond any possibility of interfering with the success of the experiment. Moreover, when spores fail to develop in such fluid- cultures it is easy to prove that the failure relates to loss of vitality on the part of the spores, and not to the presence of an inhibiting agent. This I am in the habit of doing by inoculating the same culture-fluid with other spores not disinfected ; and the rapid development of these is satis- factory evidence that in the first experiment failure to develop was not due to the small amount of mercuric chloride introduced in the inocula- tion with disinfected spores. The view, that in Koch's surface-cultures the inhibiting influence of the bichloride came into play, is sustained by his own inoculation experi- ments, and by my culture experiments reported below. Thus we are informed 1 that three mice were inoculated with anthrax spores, attached to strands of silk thread which had been exposed for ten minutes to solu- tions of the strength of 1 : 10,000, 1 : 20,000, and 1 : 50,000. All of the mice died of anthrax ; but while the one inoculated with the strand ex- posed to 1 : 50,000 died in the usual time, — on the second day, — the one inoculated with 1 : 20,000 did not die until the fourth day, and the one with 1 : 10,000 not until the fifth day. That anthrax spores may survive exposure to a solution of 1 : 10,000 for a longer period than ten minutes is also shown by the following exper- iments. December 18, 1884. A small quantity of a culture-fluid containing anthrax spores was exposed for one kou?' to mercuric chloride in the pro- portion of 1 : 10,000. No development of anthrax bacilli occurred in a culture-flask inoculated with these spores ; but in another experiment, made at the same time, in which the proportion of the disinfectant and the time of exposure remained the same, and in which a much lai-gei' quantity of the spore-containing culture-fluid was used, there was an abundant development of anthrax bacilli in the inoculated culture-flask. It is evident that in this experiment a material change in the conditions was made, although the time of exposure and the amount of the disinfect- ing agent present were the same in both cases, and that in experiments of this kind the amount of material to be disinfected must also be taken into consideration. In other words, a few germs may be destroyed by a comparatively dilute solution of the disinfecting agent, while stronger solutions will be required for the destruction of a large number of germs 1 Mitth. a. d. k. Gesundheitsamte, I, p. 277. REPORT OF COMMITTEE ON DISINFECTANTS. 4$ contained in the same amount of material. Again : It is true of mercu- ric chloride as well as of oxidizing disinfectants, such as potassium per- manganate and the hypo-chlorites, that the quantity of non-living organic material present will also materially influence the result. This is illus- trated by my experiments reported below, in which semi-solid feces was the material subjected to the action of the disinfectant. The spores of B. subtilis are destroyed by about the same proportion of mercuric chloride as is required to kill anthrax spores. . Experiment, December 22, 1884. A small amount of a culture-fluid containing the spores of B. subtilis was exposed to the action of a solu- tion of corrosive sublimate of the strength of 1 : 10,000 for thirty minutes. A like amount was exposed for one hour, and a third portion for two hours. Two culture-flasks were inoculated with spores from each. At the end of twenty-four hours those inoculated with the material exposed for thirty minutes showed an abundant development of B. subtilis, and the others remained clear. The importance of the time of exposure to the action of the disinfect- ing agent, which is clearly brought out in the above experiment, is very- well illustrated by the experiments on vaccine virus reported by Dr. W. J. Miller, of Dundee: I have made fourteen observations with this agent on vaccine. In one of these it was tested in the following manner : I placed half the contents of a well filled tube on a glass slide, and after it dried covered it with some perchloride solution (1 in 1,000), and after allowing it to lie for ten minutes washed off the perchloride gently with water, so that the film of vaccine remained. This was then rubbed up with water, and put in a tube for use. The product entirely failed to take, while the other half of the same specimen of lymph produced a good result. Another specimen was mixed with an equal quantity of the same solution (1 in 1,000), and was used an hour thereafter, disinfection being complete. Two trials were made with the same mixture prepared immediately before use, two after an interval of three minutes, and one after fifteen minutes, and in all five the lymph was uninjured. Five experiments were made with a solution of 1 in 500 and vaccine in equal proportions (=1 : 1,000. — G.M.S.), mixed respectively, immediately before use, a few min- utes, three minutes, three minutes, and five minutes, and in all the lymph was in no way affected. Two observations with lymph and a still stronger solution (1 in 250), in equal proportions, mixed immediately before use, gave the same negative result. 1 According to Arloing, Cornevin, and Thomas, the activity of dried virus of symptomatic anthrax is destroyed by mercuric chloride in the proportion of 1 : 5,000. Jalan de la Croix found that the.bacteria in beef bouillon were destroy- ed by 1 : 6,500, but that the proportion required to destroy bacteria in a beef infusion made without heat was 1 : 2,525. It is evident, that in the absence of precise information as to the time of exposure and other essential conditions, these results cannot be com- pared directly with those reported by other observers, in which the mate- rial tested or the conditions of the experiment were different. In the writer's experiments, reported in the American yournal of the Medical Sciences for April, 18S3, the bacteria in broken-down beef tea 1 The Practitioner, London, October, 1884, p. 265. 46 REPORT OF COMMITTEE ON DISINFECTANTS. (old stock exposed in the laboratory for a long time) were destroyed by two hours' exposure to mercuric chloride in the proportion of i : 10,000, the amount of material exposed to the action of the disinfecting agent being comparatively small. Extended experiments upon the disinfection of tuberculous sputum have been made by Schill and Fischer, and are reported in their paper published in the second volume of the Mittheilungen aus.de?n Kaiser- lichen Gesundheitsamtc. In these experiments the test of disinfection was failure of the material to produce tuberculosis when inoculated into susceptible animals. In a first series of experiments with dried sputem, which had been kept for several months, a negative result was obtained in every case from the following inoculations : Two guinea-pigs inoculated with mate- rial exposed for twenty-four hours to 1 : 1,000; three with material ex- posed for twenty hours to 1 : 2,500 ; and three with material exposed for twenty hours to 1 : 5,000. , In another series of experiments with fresh sputum, in which the sub- limate solution and the material to be disinfected were used in equal a77iounts, tuberculosis resulted in all of the test animals. Three of these were inoculated with material exposed for twenty-four hours to 1 : 2.000 (i. e., equal parts of sputum and of a 1 : 1,000 solution), and three to material exposed for twenty-four hours to 1 : 1,000. The failure to disinfect in these experiments was probably due to the fact that the viscid mass of sputum was not penetrated throughout by the disinfecting agent. In the successful experiment with dried sputum, the amount of material used was no doubt much smaller, and its physi- cal condition (pulverized?) such as to insure the action of the disinfect- ant upon every portion of it. In a previous paper 1 the writer has recommended the use of a solution containing 1 : 500 of mercuric chloride and 1 : 500 of potassium perman- ganate as an efficient disinfectant for sputum, and for the discharges of patients with typhoid fever and cholera. The experiments of Schill and Fischer, which I had not read when this recommendation was made, indicate that it will be necessary to use some other agent when the object in view is to destroy the infective virulence of tuberculous sputum ; and in general it will no doubt be better to use an oxidizing disinfectant, such as the hypochlorite of soda, when the germs to be destroyed are imbed- ded in masses of albuminous material, for such masses are disintegrated and destroyed by oxidizing agents, whereas corrosive sublimate has the opposite effect, in consequence of its power of combining with and coag- ulating albuminous material. For liquid fecal discharges, however, our recommendation is sustained by the experimental evidence. The following experiments have been recently made. The standard solution above referred to — mercuric chloride and potassium permanga- nate, of each 1 : 500 — was diluted one half, and mixed with an equal quan- tity of broken-down beef tea (=1 : 2,000) . After exposure for two hours, 1 The Medical News, January 10, 1SS5, p. 34. REPORT CF COMMITTEE ON DISINFECTANTS. 47 the contained germs had lost their vitality, as proved by culture exper- iments. A more difficult test was the following : The standard solution was diluted one half, and mixed with semi-solid feces in equal quantity, well mixed by stirring. Two culture-flasks were inoculated from this at the end of thirty minutes, two more at the end of one hour, and two more at the expiration of two hours. One of the flasks, inoculated at the end of an hour, broke down ; the others remained clear. In the case of the flask which broke down, it is probable that some little mass of material was introduced, which had not been thoroughly penetrated by the disin- fecting agent. When the standard solution was diluted with three parts of water, and added to an equal amount of broken-down beef stock (z=i : 4,000), two hours' exposure failed to prevent the subsequent de- velopment of the contained spores in a sterilized culture-fluid. The experimental data herein recorded seem to justify the following conclusions : Mercuric chloride, in aqueous solution, in the proportion of 1 : 10,000, is a reliable agent for the destruction of micrococci and bacilli in active growth not containing spores; and in the proportion of 1 : 1,000 it de- stroys the spores of bacilli, provided that the micro-organisms to be de- stroyed are fairly exposed to its action for a sufficient length of time. A standard solution of 1 : 1,000 may be safely recommended for the disinfection of bedding and clothing which can be washed ; for washing the floors and walls of infected apartments ; for disinfecting the hands and instruments of surgeons and gynecologists ; and as a disinfecting wash for superficial wounds or mucous surfaces. For continuous appli- cation to wounds, etc.. a solution of 1 : 10,000, or less, should be effective. A standard solution of 1 : 500, with the same quantity of potassium permanganate, may be safely recommended for the disinfection of liquid fecal discharges, and other fluid material supposed to contain "disease germs," provided the time of exposure is not less than two hours, and the quantity of material to be disinfected is not in excess of that of the standard solution used. CONSIDERATIONS CONCERNING TtfE PRACTICAL USE OF MERCURIC CHLORIDE AS A DISINFECTANT. BY VICTOR C VAUGHAN. Since mercuric chloride has been put forward as one of the most relia- ble disinfectants, its practical use has been largely discussed, and some supposed dangers in its general employment have been brought forward. It was for the purpose of ascertaining how much truth there may be in these statements that the following experiments were undertaken. Is there danger of the passage of this highly poisonous salt, from cess- pools and privy vaults in which its use has been recommended, through 48 REPORT OF COMMITTEE ON DISINFECTANTS. the soil into wells? Sanitarians have had so much to say about well- water being poisoned by the filtration of organic matter through the soil from privy vaults and cesspools, that it is not surprising that the above question should be asked. In order to answer it, the following experi- ments w r ere made : Experiment i. A large glass funnel, carrying a filter-paper, was filled with gravel taken from a distance of about four feet beneath the surface. The weight of the gravel w r as eleven and three fourths pounds, and, when placed in the funnel, it formed an inverted cone, with a base of ten inches diameter and an altitude of eight inches. On this was poured one pint of standard solution No. 2 (corrosive sublimate and per- manganate of potash, two drachms of each to the gallon of water), rec- ommended for the disinfection of excreta. After a few minutes a pint of distilled water was also filtered through the soil. This was done in order to wash through any mercury that might be held mechanically in the gravel. The filtrate was collected, concentrated to one fluid ounce, and tested for mercury. The result was negative. The soil retained all of the poison. Experime?it 2. This was similar to the above, but black loam was used instead of the gravel. The weight of the soil used was seven pounds. The result was the same as with the gravel. Experiment J. In this instance clay was used. The weight of the clay was nine and one fourth pounds. As the soil in this case was very dry, it was thoroughly moistened with water before the solution of mer- curic chloride was poured on. These experiments show that the quantities of the different soils, as given above, will remove from solution and retain all the mercury con- tained in one pint of standard solution No. 2, fifteen grains of mercuric chloride. That a much smaller amount of soil would accomplish the same result was shown by the following : Experime?it 4. One and one half pounds of gravel were placed on the filter, and one pint of standard solution No. 2, one ounce at a time, was filtered through the gravel. The filtrate contained no mercury. From these experiments it will be seen that the fear that mercuric chlo- ride may filter through the soil, when used as a disinfectant in privy vaults and cesspools, into wells, and thus poison the water, is ground- less. Of course, where there is open connection between the cesspool and wells by the formation of small subterranean rivulets, there would be danger. The fixation of mercury in the soil is doubtless largely, if not wholly, due to the presence of certain inorganic salts, such as carbonates and phosphates, which form insoluble compounds of mercury. At the recent cholera conference at Rome, Dr. Koch gave, as one of his reasons for not recommending mercuric chloride as a disinfectant, the belief that its disinfecting action was interfered with by the fact that it entered into combination with albuminous material, and thus failed to come in contact with germs enclosed in albuminous masses. 1 That a 1 The Medical News, June 20, 1885, p. 707. '•"'IPOJWrA «O^OtBSaS V ° MlCS REPORT OF COMMITTEE ON DISINFECTANTS. ^ 49 combination between the mercury and albumen does occur may be shown by the following - very simple test : Experiment 5. Suspend some recently precipitated mercuric oxide in distilled water, add some egg-albumen, agitate thoroughly, and filter. The filtrate is clear and colorless. Boil this filtrate with potassium chlorate and hydrochloric acid until all the organic matter is destroyed. Then test for mercury with hydrogen sulphide or stannous chloride. The mercury will be found to be present, and all that which was used as mer- curic oxide can be recovered. Albumen dissolves the oxide, forming, probably, mercuric albuminate ; but there is no reason for believing that the mercuric albuminate does not diffuse through organic matter. As shown in the experiments, it is freely soluble, and readily passes through the filter-paper. It is altogether probable that it is this mercuric albuminate which forms such a powerful germicide. In this compound we have the mercury in the shape in which it would most likely be taken up by those lower forms of life which feed upon albuminous material. Medical men have for a long time regarded "yellow wash" as the most successful application that could be made to syphilitic sores. Is it not likely that its great value is due to the formation of mercuric albumi- nate, which has a local action on the virus, and penetrates the tissue as well ? A substance which is not absorbed by living organisms is not poisonous to them, and if by the formation of this mercuric albuminate the most readily absorbable form of mercury is secured, its poisonous properties are intensified. Further considerations concerning the use of mercuric chloride will be presented as soon as some additional experiments are made. The writer is indebted to two of his students, Messrs. Wagner and Bobb, for aid in the experimental work. ACTION OF MERCURIC CHLORIDE ON LEAD PIPES. When a solution of mercuric chloride comes in contact with lead, there is an immediate deposit of mercury with the formation of lead chloride. That this action rapidly destroys lead pipe is shown by the following : Experiment. One foot of one half inch lead pipe was placed in a tall beaker, and 1,000 c. c. of a two per cent, solution of mercuric chloride poured into the beaker. Instantane- ously a white cloud of lead chloride formed around the pipe, and gradually subsided to the bottom. Each day the solution of mercuric chloride was changed, and the pipe washed with water. After 4,000 c. c. of the mercuric chloride solution had been used, the pipe had worn away to such an extent that on bending it the pipe would break. Since the reaction is instantaneous, the result would practically be the same, though a little slower, with the solution of mercuric chloride flow- ing through the pipe. Notes by Dr. G. M. Sternberg, chairman of committee : I have recently made some experiments to determine the antiseptic power of mercuric oxide. In the proportion of 1 : 1,000 it has prevented any development of micro-organ- isms in veal broth, inoculated with two or three drops of broken-down beef tea. In 50 REPORT OF COMMITTEE ON DISINFECTANTS. the proportion of i : 2,000 and 1 : 4,000, it restrained development for a time, but at the end of forty-eight hours the broth became clouded near the surface, and at the end of seventy-two hours had broken down completely. (The same culture-fluid broke down in twenty-four hours when not treated with an antiseptic.) This very decided antiseptic power shows that mercuric oxide is far from being " inert " from a biological point of view. Disinfecting and Antiseptic Powder. The powder under this name, for which a formula was given in the Preliminary Report of the Committee on Disinfectants, was withdrawn in a letter published in the Medical News of May 2d. The writer was responsible for this powder, and withdrew it because of the fact that mercuric chloride is decomposed by the hypochlorites in the presence of moisture. In the powder, made as directed, this reaction does not occur, and the keeping properties of the powder are all that could be desired. But when water is added to it the reaction occurs, and the yellow oxide of mercury is precipitated. This fact having been brought to my attention, I hastened to withdraw my recommendation of the powder, although I had been much pleased with it in practical tests upon feces. Since my return from Europe I have made some additional experiments, which show that, notwithstanding the destruction of the bichloride, the powder is an excellent disinfectant and antiseptic. A sample which I have recently examined contained 2.6 per cent, of available chlorine after the precipita- tion of the yellow oxide by the addition of water. This same sample, after standing in an open box in the laboratory for about three weeks, still contained 1.5 per cent, of avail- able chlorine at the bottom of the box, and 1 per cent, at the surface of the powder, which had been exposed to the air during this time. I have demonstrated, by recent experi- ments, that mercuric oxide is a valuable antiseptic. In the proportion of 1 : 2,000 it re- tards the development of micro-organisms in beef tea inoculated with two or three drops of broken-down stock; and in the proportion of 1:1,000 it entirely prevented develop- ment for a week, the duration of the experiment, while in the comparative test the beef tea broke down in less than twenty-four hours. Nevertheless, I do not endorse the for- mula which I first recommended, for the reason that mercuric oxide has an antiseptic power inferior to that of the bichloride, and it is a waste of material to use the bichloride of mercury in the same formula with the hypochlorites. I would therefore recommend that the powder be made without the addition of mercuric chloride. • My object is to dilute the chloride of lime so that it may be used more economically, especially upon the surface of fecal matter hi privy-vaults. Such a powder is especially need- ed in country places, where the old-fashioned open privy-vaults are in use, and in garri- sons and military encampments. Chloride of lime, as received from the manufacturers, is more or less lumpy, and can- not be readily scattered about in a uniform manner. It is also much stronger in chlorine than is necessary. I have therefore endeavored to find an inert substance suitable for diluting it. Plaster of Paris has the advantage of retaining the chlorine better than anything else I have tried, and makes a powder which can be readily scattered about in a thin layer. Its property of setting with water is no objection to its use in privy vaults, cess-pools, etc., but would be an objection to its use in chamber vessels, the contents of which were to be thrown into water-closets. To test the keeping properties of a mixture of chloride of lime and sulphate of lime, mixed together in equal quantities, by weight, I exposed a layer having a thickness of about one and a half inch in a shallow vessel, and for comparison, a mixture of equal parts of chloride of lime and sand in a similar vessel. At the outset of the experiment the available chlorine in each specimen was found by Dr. Abbott to be 15 per cent. At the end of a week the mixture with plaster contained 12.9 per cent, of available chlorine, and the mixture with sand 6.8 per cent. At the same time two fruit jars were filled about one third full with the two mixtures, and the metal covers were screwed on. In these closed jars the mixture with sulphate of lime contained 13.5 per cent, of available chlo- rine at the end of two weeks, and the mixture with sand 11.8 per cent. REPORT OF COMMITTEE ON DISINFECTANTS. 5 1 THE COMPARATIVE ANTISEPTIC VALUE OF THE SALTS AND OXIDES OF MERCURY. BY GEORGE M. STERNBERG. In the introduction of this report the statement is made that " a com- plete investigation of both disinfectants and antiseptics being impracti- cable in the time and with the resources at command, the committee decided upon so far departing from the letter of the resolutions of Dr. Hibberd as to limit its inquiry altogether to disinfectants, and to omit all investigations into the action of antiseptics." The present article is the result of a departure from this rule which the writer has made with reference to the salts and oxides of mercury, because of the special interest which they have from a therapeutical point of view, and because of the important indications which seem to be furnished by their antiseptic power for restricting the development of pathogenic organisms in the alimentary canal, as well as in masses of decomposing organic material which might serve as pabulum for disease germs external to the body. With the assistance of Dr. Abbott, I have recently made a series of experiments, the results of which are given in the following table : Active. Failed. Biniodide of mercury, I : 20,000 I : 40,000 Bichloride, 1:15,000 1 ; 20,000 Protiodide, 1 • 10,000 1 : 20,000 Yellow oxide, 1 : 1,000 1 : 2,000 Black oxide, 1 : 500 1 : 1,000 Calomel, 1 ■ 100 Blue mass, 1 : 100 In every case the antiseptic was carefully weighed and added to 100 c. c. of beef-peptone solution, or of veal broth. A similar quantity of the culture-fluid was put up as a temoin without the addition of the antisep- tic. As the oxides and iodides of mercury are insoluble in water, the bottle was repeatedly shaken in order to dissolve in the albuminous culture-fluid as much of the antiseptic as possible. An undissolved rem- nant could, however, be recognized at the bottom of the bottle after this repeated shaking. Two drops of broken-down beef stock were added to each bottle to cause speedy putrefaction of the culture-fluid in the absence of a sufficiently potent inhibition of the developing power of the bacteria of putrefaction. In every case in the comparative experiment the cult- ure-fluid became clouded, and had a putrefactive odor at the end of twenty-four hours. The first column in our table shows the proportion in which the cult- ure-fluid was preserved from any appearance of decomposition for at least a week, the duration of the experiment. In the proportion given in the second column a decided inhibiting power was shown, except in the case of calomel and blue mass, which, in the proportion given (1 : 100), gave no evidence of antiseptic power. The other salts and 52 REPORT OF COMMITTEE ON DISINFECTANTS. oxides in the list prevented decomposition for twenty-four hours in the proportion given in the second column ; and it was not until the second day that the bacteria of putrefaction commenced to form a cloud at the upper surface of the fluid, which gradually extended until the fluid had entirely broken down, usually by the third or fourth day. The bottles containing the biniodide (i : 20,000), and the bichloride (1 : 15,000) have now been standing in the laboratory for three weeks, and are as trans- parent and free from odor as the day they were put up. These results agree with those reported by Miquel. So far as I know, the antiseptic value of the protiodide and of the oxides of mercury has not heretofore been determined. I shall refrain at present from making any remarks upon the therapeutic possibilities which these figures suggest, or upon the possible explanation of the modus operandi of the protiodide, given daily for many months in the cure of syphilis, or of the use of yellow oxide as a remedy for septic fer- mentation in the alimentary canal. The still greater inhibiting power of mercuric chloride for the spores of B. anthracis has already been referred to in the paper published on page 41 of this report. SULPHUR DIOXIDE. BY GEORGE M. STERNBERG. Vallin, to whom we are indebted for the best practical " treatise upon disinfectants and disinfection " \ which has yet been published, says, — " Sulphurous acid, obtained by the combustion of sulphur in free air, occupies almost the first place among the veritable disinfectants." 2 This is the deliberate judgment of one who had carefully considered the experimental evidence accessible at the time this opinion was formu- lated (1882). The use of sulphurous acid gas as a disinfecting agent has come down to us from remote antiquity, and it is safe to say that no gaseous disin- fectant known is more extensively used, or has a higher place in the confidence of leading sanitary authorities at the present day. So well established is the belief that the fumes of burning sulphur will destroy the infection of small-pox, scarlet fever, yellow fever, etc., that it is prob- able that many believers in the germ theory of disease would be disposed to abandon this belief rather than to give up their faith in the disinfecting power of sulphurous acid gas, in case the experimental evidence relating to the germicide power of this agent should be in conflict with the results of their experience. It is the object of the present paper to present the experimental evi- dence for the consideration of sanitarians, and, as the subject is one of 1 E. Vallin, Medecin Principal de ire Classe de 1'Armee, Professeur d' Hygiene a l'ecole de Med. Militaire du Val-de-Grace, etc. Traite des Disinfectants et de la Disinfection, Paris, 1882. 2 Op. cit, p. 243. RErOKT OF COMMITTEE ON DISINFECTANTS. 53 great practical importance, the paper will necessarily be one of consid- erable length. Before the modern methods of isolating and cultivating pathogenic micro-organisms had been perfected, various efforts had been made to determine by experiment the disinfecting power of sulphurous acid gas. One of the first of these experiments upon record is that which the Rus- sian physicians are said to have made at the time of the pest in Moscow, in 1 771. According to Dr. A. Wolff, ten cloaks (pelisses) which had been worn by soldiers seized with the plague, during their sickness, were exposed to fumigation ( unc forte fumigation) with sulphur and salt- petre. Ten criminals, condemned to death, were then required to wear these garments, and not one of them contracted the malady. In the absence of any control-experiment in which similar garments not disin- fected were proved to communicate the disease, we cannot admit that disinfection was accomplished in this instance, as claimed by the Rus- sian physicians, by the fumigation resorted to. The same criticism may be made with reference to most of the evidence relied upon at the pres- ent day, which is supposed to establish the value of the agent in question. It is negative in character, and we have no control-experiments. More- over, accompanying or following the fumigation, other measures are commonly adopted, such as free ventilation and cleansing of apartments, exposure of clothing and bedding to an abundance of fresh air, etc. As in clinical experiments a fictitious value is often assigned to remedies by reason of the failure of the experimenter to recognize the influence of the vis medicatrix natures, so there is reason to believe a "disinfectant" may often establish a temporary reputation at least, upon the real vir- tues of an abundance of fresh air, together with a free use of hot water and scrubbing brushes, with perhaps a judicious use of the whitewash brush in addition. These remarks are made, not to throw discredit in advance upon the agent under consideration, but with a view to showing that a careful survey of the experimental evidence is necessary, and that a spirit of scientific conservatism is required when the attempt is made to estimate the value of negative evidence in a case of this kind. In vaccine virus we have an infectious material which seems especially well adapted as a test of disinfecting power, and the inference seems jus- tified that an agent which will destroy the specific virulence of this ma- terial may also be relied upon for the destruction of the small-pox infec- tion. The writer applied this test in a series of experiments made in 1SS0 and 1881, and published in the Bulletin of the National Board of Health. The results obtained have been summarized by Vallin, and, as his work is before me, I quote from it as follows : Dougal and Baxter have shown the neutralizing power o sulphurous acid upon differ- ent kinds of inoculable virus. Both exposed for ten minutes, in an atmosphere saturated with sulphurous fumes, ivory points charged with dry vaccine virus. At the end of this time the neutralized virus was inoculated by three punctures in the arm of a non-vac- cinated infant, while in the other arm, at the same time, three punctures were made with ivory points charged with the same virus, but not exposed to sulphurous acid. The last- 54 REPORT OF COMMITTEE ON DISINFECTANTS. mentioned punctures were all followed by perfectly developed vesicles ; the punctures upon the other arm gave no result. Unfortunately the quantity of the acid, or of sulphur burned, is not mentioned. This time, by exception, Baxter leaves us in doubt. Dr. Sternberg, surgeon in the United States Army, has taken up these experiments in an ingenious manner, and with greater precision. This author burned a determined quantity of sulphur in a wooden box having a capacity of ten litres. He submitted to the vapors thus produced liquid vaccine virus, placed in a watch-glass, for a period of twelve hours. The following day unvaccinated infants were inoculated in one arm with the disinfected virus, and in the other with a portion of the same virus not exposed to the disinfectant. Liquid virus thus exposed for twelve hours to the action of the fumes from 3 centi- grammes of sulphur burned in the air-chamber — that is, 24 cubic centimetres of gas to 10 litres of air, or a little more than two parts in a thousand — produced but a single vesicle, while the non-disinfected virus in the other arm gave a successful result in every instance. Upon doubling the amount of sulphur, — that is, 6 centigrammes to 10 litres, or 6 grammes per cubic metre, or 5 volumes of sulphurous acid to 1,000 volumes of air, — and reducing the time of exposure to four hours, the vaccine still remained inactive after exposure. It suffices, then, to burn 5 grammes of sulphur in a cubic metre of air, in order to neu- tralize liquid vaccine, but this vaccine coagulates almost immediately upon contact with sulphurous acid gas ; and this contributes, perhaps, to destroy, or to modify, its inocula- bility. We shall see, further on, that experiment made in spaces of such small dimen- sions may lead to grave errors. In order to disinfect dry vaccine, Sternberg found that a considerably larger quantity of sulphur was required, viz., 16 grammes per cubic metre, which corresponds with the classical proportion of 1 volume of sulphurous acid gas to 100 volumes of air. In this regard the experiments of Sternberg confirm those which have been obtained by many other authors. Baxter has also tested the power of an aqueous solution of sulphur dioxide to disinfect the virus of glanders, and an infectious form of sep- ticaemia — induced — in guinea-pigs. Four parts of S0 2 by weight, added to 1,000 parts of the diluted virus of glanders, neutralized its infective properties, as determined by inoculation experiments. The septic virus was destroyed by 3 parts by weight in 100, while 6 in 1,000 failed. The time of exposure to the disinfectant in these experiments is said to have been from thirty minutes to three hours ; but this is considered by Baxter to be a matter of secondary importance, and, according to him, disinfec- tion is complete at the end of five minutes, when the virus has been inti- mately mixed with the disinfecting solution. The wide limits (3 : 100 and 6 : 1,000) between success and failure in these experiments of Baxter, and an evident want of precision in the conditions, especially as to time, induced Vallin, from whom we have quoted the above results, to undertake additional experiments with the virus of glanders. He says, — I had, in January, 1881, an opportunity to repeat these experiments. A patient in the service of our colleague, M. Gaujat, at Val de Grace, was attacked with glanders, — abces farcineux multiples, — and furnished an inoculable pus, with which Dr. Kiener produced m several animals — guinea-pigs, cats, etc. — the characteristic lesions of glanders. A small quantity of this pus obtained directly from the patient, and placed in a watch-glass, was exposed for twelve hours in a wooden box having a capacity of exactly 100 litres. Two grammes of sulphur were burned in this box, — an amount which corresponds with 20 grammes per cubic metre. The following day a guinea-pig was inoculated with the disin- REPORT OF COMMITTEE ON DISINFECTANTS. 55 fected virus. At the end of three months this animal remained in perfect health. An- other guinea-pig, inoculated the same day with a second portion of the same virus pre- served between two watch-glasses, and not disinfected, died at the end of two months with the characteristic lesions of glanders. Additional experiments were made with the same virulent pus dried in the open air upon little squares of flannel. Inoculation with this ma- terial failed after exposure to sulphur dioxide generated by burning sul- phur in the proportion of 15 grammes per cubic metre. But inoculation with the desiccated virus not exposed to a disinfecting agent also failed, and Vallin remarks that desiccation alone had perhaps sufficed to destroy the virus, as in the experiments of Galtier. Experiments were also made with pus obtained from a tuberculous abscess in a case of Pott's disease. This material was divided into two portions, and placed in watch-glasses. One portion was subjected for twelve hours to the action of sulphur dioxide generated by burning sulphur in the proportion of 20 grammes per cubic metre. This pus, injected subcutaneously into a guinea-pig, produced no result. At the end of four months the animal remained in good health. The non-disinfected pus injected into another guinea-pig caused its death on the forty-eighth day. Its liver, spleen, lungs, and peritoneum were filled with tubercle granules. Other experiments were made with pus obtained from two chancres "of doubtful nature." Inoc- ulation with this material, after exposure to S0 2 (15 grammes of sulphur per cubic metre of space) , gave no result, while the non-disinfected pus produced "characteristic pustules." In the experiments thus far recorded, the disinfecting power of the agent under consideration is fully established for certain kinds of material, and especially for vaccine virus. In my own experiments upon this material the results were extremely definite, and the conditions observed were such as to render them unimpeachable. Experiments upon original virus from various sources are especially valuable from a practical point of view, in- asmuch as the results obtained are evidently reliable guides with reference to the destruction of infective virulence in the several kinds of material experimented upon, and this without regard to any theory as to the na- ture of the morbific agent. We know, however, that in several infectious diseases at least, this agent is a living organism or germ. It is therefore a matter of importance to determine the exact germicide power of this and other agents which have been proved to be useful disinfectants, and numerous experiments have been made with this object in view. If the germ theory of disease is correct, as applied to all infectious diseases, there should be a correspondence between the results obtained in experi- ments with original virus and those made upon pure cultures of the path- ogenic organism to which such virus owes its infecting power. This is an interesting question in connection with the agent under consideration, inasmuch as Wernitz has shown that sulphurous acid promptly neutral- izes the action of non-living ferments in comparatively small amounts, and there is therefore ground for the supposition that the specific disease poisons destroyed by this agent in the disinfection experiments above recorded were of this nature. 56 REPORT OF COMMITTEE ON DISINFECTANTS. According to Wernitz, 1 the action of pepsine, of ptyaline, of invertine, and of diastase, is prevented by the presence of an aquaeous solution of S0 2 of i : 13 1 7 to 1 : S60 (by weight) ; while the action of myrosine and of emulsine is neutralized by 1 : 21,000. Wernich, of Breslau, experimenting in the Pathological Institute of Berlin, 1877, saturated strips of woollen or cotton goods with putrid liquids, and exposed them under a bell-jar containing a definite propor- tion of sulphurous acid gas. Then, with proper precautions, these strips were introduced into tubes containing Pasteur's culture solution, thoroughly sterilized. The development of bacteria in this fluid was taken as evidence that disinfection was not complete. The results ob- tained are summarized by Vallin 2 as follows : When the strips of material were suspended for several hours under a bell-jar containing 3.3 volumes of sulphurous acid per 100 volumes of air, they were not disinfected. When the proportion of gas was increased to 7 per cent., or even to 4 per cent., the time of exposure being six hours, the strips of goods no longer fertilized culture liquids. Schotte and Gartner, 3 in 18S0, experimented also upon the bacteria of putrefaction. In a chamber having a capacity of 40 cubic metres they placed, at various levels, shallow dishes containing culture liquids, into which putrefactive bacteria were introduced. Sulphur was burned in earthen vessels, placed about four feet above the level of the floor. When the amount burned was in the proportion of 15 grammes per cubic metre of space — an amount which gives one volume of S0 2 to 100 volumes of air — it was found that at the end of six hours the gas had escaped to such an extent that it was possible to enter and remain in the room, although during the entire time the doors and windows had been care- fully closed. The result of the experiment was, that the culture liquids exposed in the upper part of the chamber remained clear, while those placed upon the floor broke down at the end of from twenty-four to thirty- six hours. When the amount of sulphur burned was increased to 2S grammes per cubic metre (about two volumes per cent, of SO.,), disin- fection w r as complete. When the culture fluids were placed upon the shelves of a cupboard, " half closed," and situated in the corner of the chamber, disinfection was only obtained by burning 92 grammes of sul- phur per cubic metre of space. We remark that the test of disinfection was not satisfactory in these experiments. A certain amount of S0 2 was, no doubt, absorbed by the exposed culture liquids ; and these, in successful experiments, failed to break down, because of the antiseptic or restraining influence of this agent. But, to prove that the germs of putrefaction in these culture liquids were killed, it would have been necessary to inoculate fresh cul- tures with a small amount of this material which had been exposed to the action of a disinfectant. 1 I. Wernitz, Ueber die Wirkung der Antiseptic a anf ' ttngeformte Fermente, Dorpat, 1SS1. 2 Op. cit., p. 234. 3 Viertelj. f. Oeff. Gesund., 1880, t. xii, pp. 337-376. REPORT OF COMMITTEE OX DISINFECTANTS, $7 Other experiments were made by the authors named, which we shall quote in the language of Vallin i 1 Strips of very thick woollen goods were soaked in culture liquids containing bacteria. These were dried, a proceeding which did not destroy the vitality of the bacteria, as proved by culture experiments. These strips were suspended from a cord stretched across the middle of the chamber at a level of about five feet above the floor. Half of the strips were left dry ; the other half, after having been dried, were again moistened, so that they might be exposed in a moist condition to the sulphurous vapors. Our authors arrived at the following unexpected results : Even after having been exposed to the action of sulphur dioxide, produced by the combustion of 92 grammes of sulphur per cubic metre, the moistened strips caused culture liquids, in which they were placed, to break down at the end of three or four days. The dry strips exposed in the same way produced the same results somewhat sooner — dans le3e joar. Gartner and Schotte have concluded from this that the germs, or proto-organisms, hidden in the deeper portions of the very thick wool- len goods, resist strong fumigations with sulphurous acid gas, or with other disinfectants. They arrive almost to the point of doubting the possibility of a certain and absolute dis- infection, at least by the gases or vapors. The limits of this paper admit only of a brief abstract of the elaborate experimental researches relating to the value of sulphur dioxide as a dis- infectant, made by Koch' 2 and by Wolffhugel, 3 under the auspices of the Imperial Board of Health of Germany, and published in the first volume of the Mittheilujigen ans dem Kaiserlichen Gesundheitsa?nte. The experiments of WolfFhiigel relate to questions concerning the practical use of S0 2 , the best methods of producing it, etc., while those of Koch are designed to fix its exact germicide value. In Koch's first experiments sulphur dioxide was generated by burning sulphur in a box having a capacity of 290 litres. Other experiments were made in a closed chamber. The amount of S0 2 present was estimated at the outset and at various intervals. Thus in his third experiment, in which the disin- fection box was used, the amount of SO^ was, — At first, 6.13 vol. per cent. At the end of 24 hours, 4.88 " " At the end of 72 hours, 4.47 " " At the end of 96 hours, 3-3 " " In tli is experiment only spore-containing material was exposed in the disinfection box. This consisted of old dried milzbrand (anthrax) blood, anthrax spores dried upon silk threads, spore-containing earth, and hay bacillus spores dried upon blotting paper. The result was entirely nega- tive : the developing power of the spores was not in any instance destroy- ed, even after ninety-six hours' exposure, and a mouse inoculated with the dried blood, exposed for this length of time, died promptly of anthrax. The results obtained with material not containing spores were more satisfactory, but still not of a nature to give confidence in this agent as a reliable disinfectant for the purposes and in the manner it which it is commonly applied. The experiments show, in the first place, that it is not safe to apply the data obtained by burning sulphur under a bell-jar, or in a tight box of small dimensions, to disinfection on a large scale, 1 Op. cit., p. 253. 2 Op. cit., pp 252-261 5 Ibid., pp. 1S8-233. ' 58 REPORT OF COMMITTEE ON DISINFECTANTS. owing principally to the rapid loss of gas which occurs in an ordinary apartment, with all apertures carefully closed. Thus in Koch's fifth ex- periment in a closed chamber, the rapid loss of S0 2 is shown by the fol- lowing figures : At the end of half an hour, 3.12 vol. per cent. At the end of 2 hours, 1.25 " " At the end of 22 hours, .015 " " In Experiment No. 2, made in a box having a capacity of 290 litres, anthrax bacilli, without spores, from the spleen of a mouse recently dead, and dried upon silk thread, were destroyed by exposure for thirty min- utes to S0 2 in the proportion of 1 vol. per cent. In Experiment No 7, also made in the box, the amount of S0 2 at the outset was .84; at the end of twenty-four hours, .55. An exposure of one hour in this experiment destroyed anthrax bacilli (still moist) upon silk thread. Four hours' exposure failed to destroy the vitality of Micro- coccus prodigiosus growing upon potato, but twenty-four hours' expos- ure was successful. The same result was obtained with the bacteria of blue pus. In Experiment No. 8, it was found that an aqueous solution of SO- 2 of 11.436 per cent., by weight, did not destroy anthrax spores in twenty- four hours, but was successful in forty-eight hours. When the propor- tion of S0 2 was reduced to 5 718 per cent., disinfection was only accom- plished after five days' immersion in the aqueous solution. According to Arloing, Cornevin, and Thomas, sulphurous acid does not destroy the bacteria of symptomatic anthrax, which contain spores. The experimental results thus far recorded will perhaps prepare those who have heretofore had implicit faith in the disinfecting power of sul- phurous acid, to accept, without too much incredulity, the following re- sults obtained by the writer in recent experiments with this agent : At the request of Dr William M Smith, health officer of the port of New York, I visited that city on the 9th of January, 1SS5, for the pur- pose of applying biological tests in an experiment designed to ascertain whether it is practicable to disinfect rags in the bale. A manufacturing chemist of New York proposed to accomplish this by injecting sulphur dioxide into the interior of the bales through hollow tubes. The S0 2 had been compressed to the liquid form in copper cylinders, and being under a pressure of six atmospheres was expected to permeate the bale thoroughly when the valve was opened leading to the hollow and per- forated screws introduced into it. The bale was to be placed in a closed chest of moderate dimensions, and disinfection w T as to be accomplished within a few minutes. The experiment was made at the Baltic stores, Brooklyn, in the pres- ence of Dr. Smith, health officer of New York ; Dr. Raymond, com- missioner of health of the city of Brooklyn ; and several other gentlemen belonging to the health departments of New York and of Massachusetts. The following material, which I had brought in sterilized tubes from the biological laboratory of Johns Hopkins University, Baltimore, was REPORT OF COMMITTEE ON DISINFECTANTS. 59 introduced into the bale through openings made with a pocket knife. The depth of these openings was from two to four inches. The material to be disinfected was upon pledgets of cotton previously sterilized, which had been saturated with pure cultures of the various test-organisms. Some of these pledgets had been subsequently dried at low temperatures, others remained moist. The apertures in the bale were closed, after in- troducing these bits of cotton, by tamping in strips of old muslin. When these preparations had been made, the bale of rags was placed in the dis- infection chamber, and the gas turned on. The time during which the gas was allowed to flow was three minutes and a half. The pressure, as shown by a gauge in connection with the copper cylinder, was eighty pounds at the commencement and seventy-five at the close of the exper- iment. The disinfection chamber was not tight, and all those in the vicinity were obliged to retire to a respectful distance to windward while the gas was flowing, and for a considerable time afterward, owing to the abundant escape and stifling effect of the S0 2 . It was only after an in- terval of twenty or thirty minutes that the disinfection chamber could be approached to withdraw the bale ; and after it had remained in the open air for some time, I was almost suffocated while removing the pledgets of cotton containing the test-organisms. These were at once placed, with sterilized forceps, in sterilized glass tubes, and each tube was at once plugged with sterilized cotton. In this way they were taken back to the laboratory in Baltimore, where the test of disinfection was completed by culture and inoculation experiments. The nature of the material and the results of the experiment are given in the following table : Number of tube contain- ing cotton pledget. No. i. No. 2. No. 3. No. 4. No. 5. Nature of material. Bacillus anthracis containing spores (dry). Bacillus anthracis containing spores (dry). Test by cultivation. One culture tube. One culture tube. Bacillus anthracis Two culture containing spores j tubes, (moist). I Bacillus subtilis j Two culture spores (dry). tubes. Bacillus subtilis j Three culture spores (moist). tubes. Result. Abundant develop- ment of anthrax filaments in twen- ty-four hours. Abundant develop- ment of anthrax filaments in twen- ty-four hours. Abundant develop- ment in both. . Abundant develop- ment of Bacillus subtilis in both. Abundant develop- ment of Bacillus subtilis in each. Test by inoculation. One rabbit in- oculated sub- cutaneously. One rabbit in- oculated sub- cutaneously. One rabbit in- oculated. Result. Died of an- thrax on third day. Died of an- thrax on third day. Survived the inocu- lation. 6o REPORT OF COMMITTEE ON DISINFECTANTS. Other pledgets of cotton had been exposed in the bale, which had been saturated with tuberculous sputum ; but this part of the experiment was not followed up, owing to the scarcity of rabbits for inoculation. Soon after my return to Baltimore, I received from the manufacturer, in New York, a copper cylinder, containing a liberal supply of S0 2 in liquid form. With this the following experiment was made, January 25, in a closet having a capacity of eight cubic yards. This closet, in the basement of the biological laboratory, had been constructed under the stairway as a refrigerating chamber. The walls were double, and filled in with asbestos ; and the door, made in the same way, was fitted to close as accurately as possible, and held closed by a strong clamp. A sufficient quantity of the liquid S0 2 to produce ten volumes per cent., when volatilized in the closet described, was drawn from the cop- per cylinder into a large beaker, quickly placed upon the floor of the dis- infection chamber, and the door closed. At the end of twelve hours the door was thrown open, and the gas permitted to escape. The test-organ- isms were exposed upon little pledgets of absorbent cotton, which had been saturated culture-fluids, containing the various micro-organisms em- ployed. Some of these pledgets of cotton had been dried at a low tem- perature in advance of the experiment, and others were exposed moist. Some of the prepared bits of absorbent cotton were placed in glass tubes, open at one end and sealed at the other. Other pledgets were loosely fold- ed in a single thickness of heavy muslin, which had been sterilized by heat. The ends of these little packages were left open, so that the SO, might have free access to the interior. These packages, properly labelled, were placed in the inside pockets of a coat, and this was suspended in the closed chamber used for the experiment. The glass tubes were placed in an open pasteboard box upon the floor of the disinfection chamber. Other pledgets of cotton, similarly prepared, were wrapped up in little bundles of cotton, weighing half an ounce each, and enveloped in a single layer of sterilized muslin. Still other pledgets were wrapped up in a woollen blanket in such manner that they were in the centre of a compact bundle, eighteen inches long and ten inches in diameter. The result, as deter- mined by cultivation experiments, was as follows : Cotton pledgets exposed in glass tubes. Micrococci from case of vaccinal erysipelas, moist and dry. No de- velopment from the moist material ; abundant development of micrococci from dry material. Bacillus subtilis (spores), moist and dry. Abundant development of B. subtilis at end of twenty-four hours from both moist and dry material. Bacillus anthracis (spores), dry. Abundant development of anthrax bacilli within twenty-four hours. Cotton pledgets placed in coat pocket. Micrococci from case of vaccinal erysipelas, moist and dry. Two culture-tubes inoculated from each. Abundant development of same micrococci within twentv-four hours. REPORT OF COMMITTEE ON DISINFECTANTS. 6 1 Bacillus anthracis (spores), moist and dry. Two tubes inoculated from each. Pure cultures of B. anthracis obtained in each within twenty-four hours. Bacillus subtilis (spores), moist and dry. Two tubes inoculated from each. At the end of twenty-four hours a mycoderma of B. subtilis was found upon the surface of the culture-liquid in each of these tubes. The complete failure thus far made it useless to open the bundles of cotton and the rolled blanket, which were put aside for further experi- ments. On the ist of February a second experiment was made in the same disinfection chamber upon test-organisms prepared as before. In this experiment the conditions were changed by the introduction of steam into the chamber through a tube connected with a retort outside. Two litres of water were evaporated, and the steam passed into the chamber during the first four hours of the experiment. The amount of S0 2 in this experiment was increased to twenty volumes per cent. ; the time of exposure was twelve hours ; the result as follows : Organisms exposed in coat pocket. Coat suspended from wall, and pledgets of cotton loosely folded in filter paper, w T ith ends of packages open for free admission of gas. B. subtilis (spores) , moist and dry. Abundant development in twenty- four hours in culture-fluids inoculated with the exposed spores. B. Anthracis (spores), moist and dry. Abundant development of anthrax filaments in culture-tubes inoculated with this material. Micrococci — pure culture — from blood drawn from inflamed area in a case of erysipelas. One moist and two dry pledgets. Pure cultures of this micrococcus were obtained from all of these after exposure in coat pocket as described. Organisms exposed on pledgets of cotton in open tubes placed upon the Jloor of disinfection chamber. B. subtilis (spores) , dry and moist. Abundant development in cul- ture-fluids. B. anthracis (spores), dry and moist. Pure cultures obtained from exposed material. Micrococci, from erysipelas (same stock as above), two pledgets, dry. Pure cultures obtained from both. The complete failure to destroy the test-organisms under the condi- tions mentioned induced me to try the following experiment : February 2. — Pure S0 2 in liquid form was poured into a tube (exper- iment in duplicate) containing spores of B. subtilis on dry cotton. The rapid volatilization of the liquid produced, of course, intense cold. As the tube was long and narrow, and volatilization was restrained by the low temperature, the time of contact with the SO.,, was at least ten min- utes. The vitality of the spores thus brought in contact with the liquid SO a was not impaired, as shown by culture experiments. 62 REPORT OF COMMITTEE ON DISINFECTANTS. The experiment was repeated February 5 with anthrax spores upon moist cotton. The result was the same. Anthrax filaments appeared in cultures inoculated with these spores at the end of forty-eight hours. It was evidently useless to extend these experiments so far as spores are concerned ; but the question remained as to the practicability of destroying pathogenic micrococci and bacilli without srjores. As Koch has shown that the loss of sulphur dioxide is very rapid from a room which is carefully closed to prevent its escape, the following experiments were made in a gas-tight receptable : February 2. — The following named test-organisms were placed under a bell-jar, having a capacity of one gallon. The jar was sealed below by resting in a trough containing mercury. Enough liquid S0 2 to make twenty volumes per cent, was introduced into this jar, and was, of course, quickly volatilized. The time of exposure was eighteen hours ; results as follows : Micrococci (pure culture) obtained from a case of vaccinal erysipelas (culture started from drop of blood drawn from inflamed area). One moist and two dry pledgets of sterilized cotton, previously saturated with this culture, were exposed in glass tubes open at one end ; also a few drops of the culture-fluid poured into a similar tube. Result negative; disinfection was complete, as proved by attempt to start cultures from the exposed organisms. Micrococci (pure culture) from blood of woman with puerperal sep- ticaemia (fatal case). Exposed one pledget of cotton, moist, in glass tube, and a few drops of culture-fluid in the bottom of two other glass tubes ; disinfection complete. Micrococci (pure culture) from vaccine vesicle. Exposed two pledgets of cotton, moist, and one tube containing a few drops of pure culture ; disinfection complete. Micrococcus urece (pure culture in beef tea) . Exposed one pledget of cotton, moist, and one tube containing a few drops of culture ; disin- fection complete. Having determined by this experiment that S0 2 , even in the absence of moisture, may kill micrococci, a second experiment was made to ascertain whether the quantity of the disinfecting agent could be reduced so as to bring it more nearly within practical limits. February 7. — S0 2 was introduced under the bell-jar, as above described, and the following test-organisms exposed to its action for twenty hours : Micrococci from vaccinal erysipelas. 1 Exposed two pledgets of cot- ton, dry, in glass tubes. From one of these, cultures of this micrococcus were obtained ; cultures inoculated from the other remained sterile. Two pledgets of cotton moistened with a recent culture were also ex- posed. Cultures from these remained sterile. A few drops of a fresh 1 The writer does not commit himself to the view that the micrococci from the various sources mentioned are specifically different, and the cause of the morbid phenomena in the individuals from whose blood the cultures were started, inasmuch as he has not been able to obtain any definite proof that such is the case. On the other hand, he admits that it is extremely probable that they are con- cerned in the development of these morbid phenomena, and are, in fact, pathogenic organisms. REPORT OF COMMITTEE ON DISINFECTANTS. 63 culture placed in the bottom of a glass tube subsequently fertilized — ster- ilized culture-fluids — failed to disinfect. M. urece, exposed upon two pledgets of cotton, moist ; disinfection complete. In the above experiment, the material to be disinfected was placed near the bottom of the jar. In the following experiment a taller jar, having a capacity of five litres, was used, and the test-organisms were exposed upon a shelf near the centre of the jar. As before, liquid S0 2 was intro- duced in an open beaker in a proper quantity to make four volumes per cent. The time of exposure was twenty-four hours. Micrococci (pure culture) from vaccine vesicle, on cotton, moist ; dis- infection complete. Micrococci, puerperal septicaemia, pure culture on cotton, moist; dis- infection complete. Micrococci, vaccinal erysipelas, pure culture on cotton, moist ; failure to disinfect. Micrococci, from vaccine vesicle, on cotton, dry, in duplicate ; disin- fection complete in one, failure in the other. I have also tested the germicide power of an aqueous solution of S0 2 on the above-mentioned micrococci, with the following results : February 5. — Equal parts of a recent culture of micrococci from vac- cine vesicle, micrococci from case of puerperal septicaemia, and M. urece, were added to a standard solution of S0 2 containing five per cent, by weight. The time of contact was two hours, after which two culture- tubes were inoculated from each ; no development occurred ; disinfec- tion complete. February 7. — The standard solution of S0 2 (five per cent.) diluted to 1 : 50 was added, in equal portions, to a pure culture of the micrococcus from vaccinal erysipelas (making the dilution 1 : 100— .05 per cent, of S0 2 by weight, or 1 : 2,000). Cultures inoculated after two hours' con- tact remained sterile. At the same time a solution of 1 : 100 was added to a culture of the micrococcus from a vaccine vesicle (t. e., 1 : 4,000 by weight) ; in this case disinfection failed. February 10. — The above experiment was repeated with the last- mentioned micrococcus with solutions containing 1 : 1,000, 1 : 2,000, and 1 : 4,000 of S0 2 by weight (after admixture with the culture-fluid). The result corresponded with that previously obtained. Disinfection was accomplished by the solution of 1 : 1,000 and 1 : 2,000, but failed when the amount was reduced to 1 : 4,000. February 11. — The same result was obtained with a recent culture of the micrococcus from case of puerperal septicaemia, i.e., the standard solution of five per cent., when diluted with forty-nine parts (1 : 50) of distilled water, in two hours' time destroyed the developing power of this micrococcus, while the same solution diluted to 1 : 100 (1 : 4,000 of S0 2 by weight) failed to disinfect. These results correspond with those reported by Jalan de la Croix, who found that one grain of S0 2 in 2,000 of bouillon filled with growing 64 REPORT OF COMMITTEE ON DISINFECTANTS. bacteria causes development to cease, and destroys the vitality of these bacteria. When spores were present, however, it was necessary to in- crease the amount to i : 135 (in how long a time?). I may add, as a matter of interest, although not directly relating to our present object, that the same standard solution of five per cent, by weight, when added to culture-fluids in the proportion of 1 : 250 (z=i :5,ooo of S0 2 by weight) , prevents the development of all the above- mentioned micrococci, while 1 : 500 (1 : 10.000 of S0 2 ) fails to prevent the development of the bacteria of putrefaction, or of the micrococcus from a vaccine vesicle, upon which organisms alone I have thus far tested the antiseptic power of this agent. These results also correspond closely with those of de la Croix, and show that sulphur dioxide ranks very high as an antiseptic. In view of the experimental data recorded, it is evident that the use of sulphur dioxide for the disinfection of spore-containing material must be abandoned. This is the conclusion of Wolffhiigel 1 on the basis of Koch's biological tests, and his own experiments. He is therefore inclined to abandon entirely the use of this agent for disinfecting purposes. He says, with reference to the question of its use for material not containing spores, that the answer to this question has very little interest from a practical point of view, as it is impossible to say in the present state of knowledge whether we have to deal with material free from spores or otherwise. Under the circumstances WolrThiigel thinks that we shall do well to abandon sulphur dioxide, and to use only such methods of disin- fection as will be effective without reference to the presence or absence of spores. I am not ready to go to this length, and to recommend the abandon- ment of an agent which enjoys the confidence of practical sanitarians for the destruction of the infection of small-pox, of scarlet fever, of diph- theria, of cholera, and of yellow fever, upon the ground that it fails to destroy the spores of the anthrax bacillus, or of B. subtilis ; for the truth of the germ theory has not yet been definitely established for any one of the diseases named, and Wernitz has shown the power of this agent to neutralize non-living ferments. Admitting, however, as I do, the great probability that the infectious agent in these diseases is a living germ, we have good reason for believing that spores are not formed in any one of these diseases. We must not then be too exacting with reference to this agent until we are able to recommend something better in its place for the purposes to which it is commonly applied, viz., for the disinfec- tion of apartments and ships. My experiments show most conclusively that it does destroy the spe- cific infecting power of vaccine virus dried upon ivory points when pres- ent in the air of a disinfecting chamber in the proportion one volume per cent., and that in aqueous solution it destroys the vitality of various micrococci in comparatively small amounts. It is even practicable to destroy these organisms dried upon pledgets of cotton by long iQp. cit., vol. 1, p. 232. REPORT OF COMMITTEE ON DISINFECTANTS. 65 exposure in gas-tight receptacles. But the conditions of success are such that it appears almost impracticable to conform with them in practice on a large scale, and it is evident that much of the so-called " disinfection" with this agent is a farce. I am convinced that the percentage of S0 2 present in the disinfection chamber, above a certain limit, is of less moment than certain conditions relating to the material to be disinfected. Thus, Koch succeeded in destroying the vitality of anthrax bacilli, still moist from the spleen of a mouse, and attached to silk threads, by exposure for one hour to .48 volume per cent, of S0 2 , in a disinfection chamber the atmosphere of which was loaded with moisture. In my own experiments with vaccine virus upon ivory points a still smaller amount (5 volumes per 1,000) was effective in four hours' time. Here the favorable conditions are without doubt the very thin stratum of material to be disinfected, and the fact that it is thoroughly moistened. Admitting that, in the absence of spores, micro-organisms suspended in the atmosphere, or attached to the surface of objects, maybe destroyed by sulphur dioxide when generated in a sufficient quantity in a well- closed apartment and in the presence of moisture, the question remains whether the same object may not be as well accomplished by thorough ventilation, and by washing all surfaces — walls, ceilings, floors, furni- ture, etc. — with a 1 : 1,000 solution of mercuric chloride, which we know to be promptly destructive of germs of all kinds. EXPERIMENTS WITH SULPHUROUS ACID GAS. BY J. H. RAYMOND. The following experiment was made in Brooklyn, at the request of the commissioner of health, with the object of determining the germicide value of sulphurous acid gas, produced by the burning of sulphur in the manner recommended by boards of health generally. Dr. George M. Sternberg, U.S. A, kindly proffered his services, and conducted the inoculation with the material prepared by him at Johns H'opkins Univer- sity. The methods employed were the same as he has employed in sim- ilar experiments, and which he has repeatedly described. Dr. W. E. Griffiths, of Brooklyn, and the reporter assisted in the experiment. The room selected was on the second floor of a private residence, and connected with it was a small clothes-closet. Two doors opened out from it, — one into the hall, the other into an adjoining room. The experi- mental room had a single window. All cracks and crevices by which fumes could escape were carefully closed by cotton. In the room were the following articles : A carpet on the floor ; a wooden bedstead with springs, on which were two mattresses in close contact ; a chair, over which was spread a bed-quilt ; a sofa ; an empty stand of drawers, on the top of which was placed a large book ; the closet was empty. The 66 REPORT OF COMMITTEE ON DISINFECTANTS. room and closet together contained, as nearly as could be ascertained, 1,850 cubic feet of air space, and were in free communication. On the 1 8th of April pieces of blanket, about four inches square, soaked with blood from a rabbit killed while affected with septicaemia, and other similar pieces soaked with blood from another rabbit affected with anthrax, were exposed in different parts of the room, as hereafter described. Some of these pieces were folded double, with the blood in- side the fold ; others were left unfolded. Piece No. 1, soaked with septicemic blood, unfolded, was placed on the floor of the closet. No. 2, septicemic blood, unfolded, was pinned to the upper part of the window frame, eight feet from the floor. No. 3, septicemic blood, folded, was attached to frame of closet door, seven feet from the floor. No. 4, septicemic blood, unfolded, was placed between the mattresses, which were in close contact. No. 5, septicemic blood, unfolded, pinned to the under side of the bed- quilt, which was spread over the chair. No. 6, anthrax blood, unfolded, placed on the closet floor. No. 7, anthrax blood, folded, attached to frame of closet door, seven feet from the floor. No. 8, anthrax blood, unfolded, placed between the lower mattress and springs. No. 9, anthrax blood, unfolded, attached to frame of the door leading into the adjoining room, six feet from the floor. No. 10, anthrax blood, unfolded, placed between the mattresses. No. 11, anthrax blood, unfolded, placed under the carpet, eight inches from the edge, the carpet again laid down, but not tacked. No. 12, anthrax blood, unfolded, placed in the middle of the book, between the leaves, the book being closed. No. 13 was a piece of blanket soaked with anthrax blood, which was not exposed in the room, but was prepared for purposes of comparison. No. 14 was another piece soaked with septicemic blood, and also not exposed. Two half-quills of fresh bovine vaccine virus were placed on the stand of drawers, and one half-quill on the top of the frame of the door leading into the adjoining room. The corresponding halves, similarly marked, were placed in a tight preserve jar, which was at once put in a refrig- erator in another part of the house. In the middle of the room was placed a large coal scuttle nearly filled with wet ashes, and in this an iron pot holding four pounds of broken sulphur and two pounds of flowers of sulphur. This was then well moistened with alcohol, and a lighted match applied. When the sul- phur was well burning the door of the room was closed, which was at 1 : 25 p. m. At u : 25 p. m. the hall door and window were opened for one hour, and the room thoroughly aired. At the end of this time the odor of sulphur was distinctly perceived, but there was no difficulty of REPORT OF COMMITTEE ON DISINFECTANTS. 67 breathing in any part of the room. The sulphur in the pot was com- pletely consumed. At the end of the hour the door and window were again closed, and kept so until 10 A. m. the following day, the 19th. When the door was again opened the air of the room was so impreg- nated with sulphur that respiration was impossible, and an airing of ten minutes was necessary before it could be entered. At the end of this time the pieces of blanket were collected, and at 12 m. healthy rabbits were inoculated by Dr. Sternberg with the blood soaked out from the pieces of blanket in sterilized beef tea. The rabbits, so fast as inoculated, were put in a cage, each in a separate compartment, and given the same numbers as those of the pieces of blanket, with the blood of which they had been inoculated. The inoculation was complete within an hour. The vaccine which had been exposed to the fumes was put into the jar containing the non-fumigated virus, and the jar replaced in the refrigera- tor, where it was kept until the material was used in vaccination. RESULTS. Rabbit No. 3, inoculated with septicemic blood from folded piece, which had been fumigated, was found dead in the cage at 7 A. m., April 2 1 st, forty-three hours after inoculation. He was apparently well the night before ; the exact time of death is not known. Rabbit No. 14, inoculated with non-fumigated septicemic blood, died at 2 p. m., April 21st, fifty hours after inoculation. Rabbit No. 7, inoculated with anthrax blood from folded piece which had been fumigated, was found dead at 7 a. m., April 23d, ninety-one hours after inoculation, being apparently well the night before. April 20th a child, 7 months old, previously unvaccinated, was vacci- nated by Dr. Griffiths in two places upon the same arm, one with virus from the fumigated half, and the other with virus from the non-fumigated half, of the same quill. The latter was successful; the'former failed utterly. The same was practised upon a young lady, 20 years of age, showing no vaccine cicatrix, and stating that she had never been vaccinated, with a fumigated and a non-fumigated half of a quill with the same result, namely, failure from the fumigated and success from the non-fumigated slip. A calf was vaccinated in the same way, on the inner sides of the two thighs, with the same result. Interpretation of Results. There seems to be no doubt that sulphur- ous acid gas, produced from burning sulphur, destroys the vitality of vaccine virus. This has been heretofore demonstrated by Dr. Sternberg, and this experiment confirms it. It will be noticed that the rabbit inoculated with non-fumigated septi- cemic blood, No. 14, died, as did also No. 3, the one inoculated from the folded piece of blanket ; while all the other rabbits, inoculated with X 6S REPORT OF COMMITTEE ON DISINFECTANTS. septicemic blood, were apparently unaffected, and survived — even No 4, which was inoculated with blood from the blanket placed between the two mattresses in close contact. I cannot understand how the gas could more readily have found its way between the mattress, and destroyed the germs there placed, than between the folds of a small piece of blanket hung up in the room. As the rabbit inoculated with non-fumigated anthrax was apparently unaffected, while one inoculated with fumigated anthrax died, I think no conclusions of any value can be drawn from this part of the experiment. Finally, after a careful review of the experiments and its results, I am led to regard the vaccine experiment as a success, and confirming what has already been well settled — the experiment with septicaemia as unsat- isfactory, and the one with anthrax as a failure. As a matter of precaution, the rabbits were kept for one month after inoculation, at the end of which time all were well, save the three already referred to. Note. — The experiment with the septic virus seems to me to have been quite satisfac- tory and definite. The temohi died at the proper time, showing the potency of the virus. This potency was destroyed by the action of the sulphur dioxide in every case except in that in which the piece of blanket was folded, while the septic blood was still moist. This was the most difficult test, as the layer of dried blood to be penetrated was twice as thick as in the unfolded pieces of blanket, and it was necessary that the gas should pene- trate an entire thickness of blanket saturated with dried blood, in order to reach the germs included in the material on the inside which cemented the folds of blanket to- gether. The failure of the temoin in the anthrax experiment is a sufficient reason for ex- cluding this part of the experiment. This failure was no doubt due to the fact that my anthrax stock is very much " attenuated" in virulence by having been cultivated in fluid media through many successive generations, and exposed often for weeks to the action of oxygen in the hermetically sealed flasks in which I keep my pure cultures. I have found that this same stock fails completely to kill white rats, but it commonly kills rabbits. Possibly the temohi in this experiment did not receive as large an amount of material as was injected into the rabbit, which died from the inoculation with anthrax blood taken from the folded blanket. The fact that this rabbit did die shows the virulence of the material, and it is extremely probable that this virulence was destroyed by the disinfectant in the unfolded pieces of blanket, although, as stated, this cannot be accepted as demonstrated, owing to the fact that the temoin did not die. G. M. Sternberg. EXPERIMENTS ON BURNING SULPHUR IN CLOSED ROOMS, UNDER DIRECTION OF J. H. RAYMOND.i In these experiments the following points have been considered : The action of sulphur fumes on various ordinary insects and different kinds of cloth, the amount of sulphur which may be burned in a given volume of air, the volume of gases resulting, and the nature and extent of the de- composition of sulphurous acid in the presence of moisture after the combustion of the sulphur in the process of disinfection. As being closely connected with these subjects, we also include in this report the following statement of the physical changes which sulphur 1 By W. H. Kent, Ph. D., chemist to the the Brooklyn Health Department. REPORT OF COMMITTEE ON DISINFECTANTS. 69 undergoes in the process of combustion. This we quote from Lunge's standard work on the " Manufacture of Sulphuric Acid :" Sulphur melts at 111.5 C. (232. 7 F.), and forms a thin light yellow liquid, which, on being more strongly heated, becomes darker and thicker; at 250 to 260 C. (48o°to 500 F.), it is nearly black, and so viscid that it does not run out when the vessel is upset ; at a still higher temperature it becomes thinner again, keeping its brown color ; and at 440 C. (S24 F.) it boils, forming a brownish red vapor ; but it begins to volatilize before boiling. This is by heating out of contact with the air. When heated in the air, the same changes take place until the temperature of combustion is reached, which, according to Lunge, is 260 C. (4S2 F.). It then takes lire and burns with a purplish blue flame, forming S0 2 , and giving out 2,221 metrical units of heat. In consulting the literature of the subject, we find a very important article on the " Value of Sulphurous Acid as a Disinfecting Agent," by Dr. G. WolfFhiigel, which in this connection should be noticed. Dr. WolrThiigel 1 gives experimental work on the following questions: 1. How may the requisite amount of sulphurous acid be with safety produced by means of burning sulphur in closed rooms? 2. What method is best adapted to determine the amount of sulphur- ous acid in the air, and the amount of gas taken up by the disinfected articles? 3. To what extent does the sulphurous acid in the air deviate from the amount calculated from the sulphur burned? What are the causes of this deviation, and how is the loss to be limited? 4. Does the gas formed distribute itself uniformly through the room, and do the articles in the room take up a large amount of the gas formed? 5. Does the gas leave the' disinfected articles uninjured, or are they depreciated in value by treatment with sulphur? 6. What concentration of the gas suffices for the purposes, and what arrangement of the experiment is necessary to guarantee the results of disinfection? Following this article in the same publication (pp. 234-2S2) is also one by Dr. R. Koch, in which, in connection with other disinfectants, he considers the amount of sulphurous acid, and time necessary to kill cer- tain microscopic organisms. With this mere notice of the nature of these papers, we pass to a description of our own experiments. For a confined space in which to burn the sulphur, a room entirely enclosed by wood was at first used. The pine boards forming the walls, ceiling, and floor were generally matched, but in spite of continued calk- ing with rags, its condition, as to tightness, remained unsatisfactory ; however, three experiments with burning sulphur were performed, and a part of the desired results obtained. It was then abandoned, with the idea that the results, witli regard to the amount of sulphur which it is possible to burn in a given space, would be of no value. We will call 1 Mittheilungen aits item Kaiserlichcn Gcsundheitsamte, vol. 1, pp. 188-233. Berlin, 1S83. JO REPORT OF COMMITTEE ON DISINFECTANTS. this room Room A, and the small bed-room, with plastered walls, which was afterwards used, Roo?n B. Room A was sixteen and one half feet long, eight and one third feet wide, and eleven feet high, and contained therefore 1,512.5 cubic feet (42,831.8 litres or 42.S31S cubic metres). In one side was a window about two by two and one half feet ; in the adjacent side nearer the floor was also a single pane of glass about eight by ten inches. Experiment No. 7, Room A.— '-In a large tin pan holding about twelve quarts (ordinarily known as a dish-pan) was placed an iron kettle hold- ing five and one half quarts, and supported in the pan by an earthen plate ; in the kettle were placed six pounds of broken brimstone and flowers of sulphur, and surrounding it, in the pan, were 8 litres (about 8 quarts) of water. The kettle stood in the water therefore to the extent of about half its height. In the water was placed a maximum and mini- mum thermometer. Before the larger window was suspended in the room one wire fly-trap with about a dozen flies, another with six or eight ants, and another with half a dozen croton bugs ( Ectobia Germanica). The fly-traps used in these experiments were made of tinned wire, — those painted with Paris green being in all cases avoided. There was also a thermometer so hung inside the room by the window as to show the temperature of the room from outside. Suspended on a line in about the centre of the room were one hundred and sixteen samples of various kinds of cloth, the coloring matters of which had been determined by Dr. O. Grothe. The samples consisted of, — Eighteen samples of all wool dress goods (Sicilian cord) dyed with various combinations of logwood black, logwood brown, picric acid, indigo carmine, and Bordeaux. Eight samples of silk dress goods (silk cord), which were also vari- ously dyed with Bismarck brown, nigrosine, alkali blue 2 B, Bordeaux, tropaeline 3 O No. 2, and roacelline. Eleven samples of domestic calicoes printed in many figures with catechu brown, logwood black, logwood blue, alizarine red, aniline yellow, and aniline blue. Twelve samples of French satins also printed with aniline black, ani- line yellow, alizarine red, indigo, logwood black, fiset wood, eosine, nigrosine, Bordeaux, and alkali blue. Twenty-four samples of Scotch gingham colored with different com- binations of Bismarck brown, logwood black, logwood blue, logwood brown, indigo, aniline blue, aniline yellow, alizarine red, alizarine rosa (tin salts), catechu brown, tropaeline O (chrysoine), turmeric, tropaeline O 4, fiset wood, and vesuvine. Twenty-four samples of domestic cambrics variously printed with ani- line blue, aniline yellow, logwood black, logwood blue, logwood brown, alizarine red, catechu brown, indigo, indigo carmine, naphthaline yellow, induline, and wood blue with chromine. Three samples of oriental flannels dyed with induline, malachite green, and Bordeaux. REPORT OF COMMITTEE ON DISINFECTANTS. J I Sixteen samples domestic flannels dyed with Bordeaux, Victoria yellow, fuchsine, methyl violet, logwood black, alizarine red, induline, and brill- iant blue (alkali blue 5 B). Duplicate samples of each of these were retained for comparison afterward. Those exposed to the sulphur fumes were numbered the same as the original, and with the additional mark of the letter x. The sulphur was ignited with burning alcohol, and the room closed as soon as possible. The time necessary for killing the insects, as observed from the win- dow outside, was as follows : All flies were dead in 22 minutes ; all ants were dead in 24 minutes ; all croton bugs were dead in 25 minutes. The temperature of the room as noted each half hour was as follows : 10: 35 a. If., yf F. — at beginning. 11:05 « 85^ « J The room became cloudy with smoke so that the burning sulphur could not at all times be seen. — Saw the flame for the last time. "=35 M 91° - 12:05 i ?. M . 94° " 12:35 5 Lyon's Patent Steam Disinfector. [Dr. Parsons's report, p. 293.] This consists of a large and strong iron chamber, with double walls of boiler plate, and provided with a tightlv fitting door at one or both ends. Fie. a;. The chamber is usually made elliptical in section, the long diameter of the ellipse being vertical for the more convenient reception of bulky arti- cles, as mattresses, sofas, etc. In its original form it had a door hung ROOM F DISINFECTED on hinges at one end only, the back being steam jacketed like the cir- cumference. This form was made* to run on wheels for removal from place to place, if desired. io6 REPORT OF COMMITTEE ON D IS EYE EC TA NTS. Another form, designed for a town disinfecting station, and intended to be placed in the partition wall dividing the building into two sides for infected and disinfected articles re- spectively, is cylindrical, and has a door at either end. The doors swing on hinges, their weight being borne by a castor running on a curved rail. The door shuts against an India-rub- ber collar, and is fastened with screws to make a steam-tight joint. Steam from a boiler can be admitted into either the hollow casing or the inte- rior of the chamber. A steam gauge registers the pressure. If a higher tem- perature is desired in the chamber, it may be secur- ed by increasing the press- ure of the steam in the casing. The latter pro- cedure has an additional advantage, as it prevents the condensation of the steam in the chamber, thus keeping it in the condition of " dry steam." Fig. 27. Benham & Sons' Steam Disinfector. [Dr. Parsons's report, p. 297. ] Fig. 2S. This consists of a rectangular iron chest resembling a fire-proof safe, the internal dimensions being 3 ft. long, 1 ft. 6 in. wide, and 3 ft. 6 in. high. It is surrounded by a steam jacket one nch thick, except on the side formed by the door, and for a space three inches in width surrounding it. The chest itself is of cast iron, the outer wall of the jacket being ^e in. boiler plate. Steam from a boiler can be REPORT OF COMMITTEE ON DISINFECTANTS. 107 admitted both into the casing and into the interior of the chamber. The door is formed of a plate of cast iron strengthened by ribs and opening on hinges. The face against which it shuts is furnished with an India- rubber collar set into a groove. The door is secured by a single large screw in the centre, working into a female screw in a strong iron bar which lies across the mouth of the chamber, resting in a groove on either side, so that it can be removed to allow articles to be placed in the cham- ber. This form of fastening allows the door to be opened with great facility and expedition, but is not adapted to sustain a high pressure. Bradford's Steam Disinfector. [Dr. Parsons's report, p. 300.] This apparatus is a horizontal cylinder of boiler plate 7 ft. long and 4 ft. in diameter, supplied with steam from a boiler. It is covered with a non-conducting composition. It has not a complete steam jacket, but there is a square steam chamber applied to the bottom, into which steam can be let by a branch pipe in order to warm the cylinder. This cham- ber is furnished with a "steam trap" to run off condensed water. The cylinder has a door at either end. The doors are hung from wheels run- ning on bars overhead. The two ends of the cylinder are isolated from each other by a partition wall dividing the apartment in which the ma- chine is contained into two rooms, as in Lyon's apparatus. Gibier's Movable Disinfecting Stove. [Journal (T Hygiene, July 22, 1886.] M. Paul Gibier recently presented at the Academy of Medicine of Paris a design for a steam disinfecting stove, which has many novel features. The apparatus may be taken to pieces and easily transported. The in- ventor claims as one of its advantages that it can be taken into the sick- room, and disinfection of infected articles accomplished on the spot. The base consists of a stove, the top of which is formed of a shallow basin constituting the boiler. From an outlet in the bottom of the boiler a pipe runs to one side of the stove-case, where it terminates in a stop- cock. By this means the boiler is emptied of water when the disinfec- tion is completed. Over the boiler is a perforated plate, upon which the objects to be disinfected are placed. This forms the bottom of the disin- fecting chamber, which is made of segments of sheet iron covered with felt to retard escape of heat. The different segments are easily and rap- idly joined by means of the clamp-screws, as shown in the figure. After the articles to be disinfected are placed in the chamber, the top, which is furnished with a thermometer projecting into the interior of the chamber, is put into its place and fastened by means of clamps. A steam pipe furnished with a stop-cock leads from the top of the chamber into io8 REPORT OF COMMITTEE ON DISINFECTANTS. the stove pipe, which connects with the chimney. The fuel used is wood, coal, or coke. In order to use the apparatus, the boiler is filled with water, and the fire lighted. The infected articles are placed in the chamber, the top clamped on, and the cock (R K) on the steam pipe turned off in order to raise the pressure in the chamber. This need not, indeed, cannot, be raised much above the ordinary pressure of the atmosphere. The steam given off from the open surface of the boiler penetrates the objects to be disinfected, and rapidly destroys all pathogenic organisms. By means J^fr/Uu**