SECTION VII.— VARIOUS DISINFECTING AGENTS. In the present section we give, for convenience of reference, an abstract of some of the more important recent researches made in the laboratories of Europe. It must be remembered, in comparing the results reported by different experimenters, that they cannot be expected to correspond unless the con- ditions under which their experiments have been made were identical. A small amount of material may be sterilized by a given percentage of a certain chemical agent, when the same proportion would fail to sterilize a larger amount. Thus, if we add a drop of material containing any test-organism to a considerable quantity of a disinfecting solution of a given strength, it will be a very different matter from adding the same proportion of the disinfecting agent to a considerable quantity of material containing the same test-organism. A gramme of chloride of lime, or of carbolic acid, is efficient for the sterilization of a certain amount of material containing the typhoid bacillus or the cholera spirillum; and the exact amount will depend both upon the number of germs to be destroyed and upon the character of the material with which they are associated. The quantity of water used in making a solution of the dis- infecting agent will, within certain limits, be a matter of no consequence. Thus, one hundred parts of a one per cent, solution of a disinfectant is equal to ten parts of a ten percent, solution of the same agent. If, therefore, the statement is made that this agent is effective in the proportion of 1 : 100, it is evident that we must know the conditions under which it is effective in order to guide us in our practical measures of disinfection, or to enable us to compare the results of different experimenters. The apparent discrepancies in the results reported below are for the most part due to the different conditions under which the experiments were made.
<Callout type="important" title="Important">Disinfecting agents' effectiveness varies based on the amount and type of material being treated.</Callout>
In the Revue Scientljique of Nov. 22, 1884, is a report by Nicati and Rietsch upon the vitality of the spirillum of Asiatic cholera. In these experiments a small quantity of a culture of the spirillum was added to a considerable quantity of the disinfecting solution : Sulphurous acid. A saturated aqueous solution, diluted with nine parts of water, destroyed the cholera spirillum in fifteen minutes. Sulphuric acid (of 66 degrees Baume), i : 400 was effective in forty minutes. Hydrochloric acid (1 gr.=o,^6^ Hcl.), 1 : 2,000 in five minutes. Acetic acid, 1 : 500 in ten minutes. Tartaric acid, 1 : 1,000 in one hour. Carbolic acid, 1 : 200 in ten minutes. Salicylic acid (saturated solution at 170 C), 1 : 1,000 in ten minutes. Sulphate of zinc, 1 : 333 in ten minutes. Chloride of zinc, 1 : 1,000 in ten minutes. Sulphate of copper, 1 : 3,000 in ten minutes. Mercuric chloride, 1 : 300,000 in ten minutes.
Desiccation. Nicati and Rietsch say, — 'Our experiments verify one of the assertions of M. Koch, which has perhaps met with the greatest incredulity, that is, that the cholera infection is surely killed by desicca- tion.' Exposure for an hour and a quarter, upon the surface of a glass plate, was found to kill the spirillum. Van Ermengem 1 has also verified this fact, but has found that the time required to effect desiccation and the death of the spirillum depends largely upon the nature of the material containing it, and the humidity of the atmosphere. When a layer of nutritive gelatine or of agar-agar, having a thickness of to 3 m m. was exposed upon glass plates, in an occupied apartment in which the temperature was about 130 C, and the air tolerably dry, sterilization was not effected in less than two or three days. In a cham- ber in which the temperature ranged from 5 to 120 C, and which was quite humid, desiccation required a longer time; but after exposure in this chamber for six days, the vitality of the spirilla was destroyed.
Van Ermengem has also made extended experiments upon the disin- fecting power of various chemical agents, as tested by the cholera microbe (op. cit.). We give a summary of his results: Sulphur dioxide. The atmosphere of a chamber was almost saturated with sulphurous vapors. In the corners and under the furniture I placed morsels of a woollen carpet, of fragments of a folded blanket, and of various stuffs rolled in bundles. In the interior of each of these packets was a morsel of blotting paper folded four times, and surrounded by a fragment of sterilized woollen cloth so as to protect the blotting paper, which had been soaked with a liquid culture of the cholera microbe, against all contamination. Even after rumaining for twenty-four hours in the chamber, the paper was never com- pletely sterilized.
Mercuric chloride. In Van Ermengem's experiments the mercuric chloride was mixed with bouillon and added to cultures of the cholera spirillum in the proportion of one vokime to five. It was found to be effective in the proportion of 1 : 60,000, the time of exposure being half an hour. When one volume of the culture-liquid was added to one hun- dred volumes of the disinfecting solution, sterilization was effected by i : 100,000.
Carbolic acid. Solutions containing 1 : 600 to 1 : 700 were found to destroy the spirilla in concentrated chicken bouillon in less than half an hour; in blood serum, 1 : 400 was effective in the same time. Copper Sulphate. Solutions of 1 : 600 were found to kill all of the spirilla in a culture in bouillon in less than half an hour. In the propor- tion of 1 : 1,000 the same culture-liquid was sterilized in from three to four hours; cultures in blood serum required 1 : 200.
Chloride of zinc (chemically pure) produced a complete sterilization in half an hour, in the proportion of 1 : 500. Zitic sulphate. 1 : 300 failed to sterilize (a single experiment). Sulphuric acid, 1 : 1 ,000 effective in half an hour. Hydrochloric acid, 1 : 2,000 effective in half an hour. Acetic acid (glacial) , 1 : 300 in half an hour. Citric acid, 1 : 200. Tartaric acid, 1 : 200. Sulphate of iron, 1 : 20 in half an hour, probably due to presence of free sulphuric acid in the commercial sulphate of iron. 'In several ex- periments made with a saturated solution of sulphate of iron added to an equal quantity of a culture in fluid blood serum, sterilization was not effected.' Salicylic acid, 1 : 300. Boric acid, 1 : 300. Thymol, 1 : 400.
Ramon and Cajal * report that the cholera spirillum is destroyed by hydrochloric acid in the proportion of 1 : 500, by sulphuric acid in 1 : 200, by carbolic acid in 1 : 50, by sulphate of copper in 1 : 100. Leitz,2 in his studies relating to the bacillus of typhoid fever, reports the following results: The dejections of the typhoid patients, mixed in equal quantity with the disinfecting solution, were sterilized by carbolic acid in five per cent, solution in three days; by sulphuric acid, in five per cent, solu- tion, in three days. Pure cultures of the typhoid bacillus, mixed with an equal quantity of the disinfecting solution, were sterilized by sulphate of iron, 1 : 20, in three days; sulphate of zinc, 1 : 20, in three days; sulphuric acid 1 150, in fifteen minutes, 1 : 20 in five minutes; carbolic acid, 1 : 20 in fifteen minutes, 1 : 10 in ten minutes; sulphate of copper, 1 : 20, in ten minutes ; chloride of lime 1 : 20, in five minutes.
In Vir chow's Archiv of March 2, 1887, is a paper by Guttmann and Merke, of the City Hospital Moabit, in Berlin, relating to the disinfec- tion of inhabited apartments. In making their experiments, the authors had in view the necessity of effectually destroying infectious disease germs with an agent which should not injure the house or furniture, or iAbst. Rev. d. sci. med. t. xxviii, p. 532. 2 Bakteriologische Studien zur typhus Aetiologie, Miinchen, 1886. 176 REPORT OF COMMITTEE ON DISINFECTANTS. be dangerous to the health of the persons who apply it. The anthrax bacillus attached to silk threads (dried) was taken as a test-organism. The disinfecting solutions were applied directly to walls, ceilings, and floors, or, in the form of spray, to rags, etc. The conclusion is reached that a solution of mercuric chloride of 1 : 1,000, applied as a wash or spray, is the most reliable and the cheapest disinfecting agent for use in inhabited rooms. This corresponds with the recommendations of the Committee on Disinfectants made in their report of 1885.
PTOMAINES. By VICTOR C. VAUGHAN, Ph. D., M. D., Ann Arbor, Mich. A ptomaine is a chemical compound, which is basic in its character, and which is formed during the putrefaction of organic matter. The name was suggested by Selmi, and is derived from the Greek word -rtirxa (cadaver). On account of their basic properties, in which they resemble the vegetable alkaloids, ptomaines may be called putrefactive alkaloids. They have been called animal alkaloids, but this is a misnomer, because some ptomaines are formed by the putrefaction of vegetable matter, as will be shown further on. While some of the ptomaines are highly poisonous, this is not an essential property, for others are wholly inert. Indeed, the greater number of those which have been isolated up to the present time are not poisonous. On the other hand, all poisonous sub- stances formed during putrefaction are not ptomaines. Thus, phenol, some of the amide-acids, and hydrogen sulphide are poisonous products of putrefaction, but are not ptomaines. All ptomaines contain nitrogen, as an essential part of their basic character. In this, also, they resemble the vegetable alkaloids. Some of them contain oxygen, while others do not. The latter correspond to the volatile vegetable alkaloids, nicotine and conine, and the former correspond to the fixed alkaloids. Since all putrefaction is due to the action of bacteria, it follows that all ptomaines result from the growth of these micro-organisms. The kind of ptomaine formed will depend upon the individual bacterium engaged in its production, the nature of the material being acted upon by the bacterium, and the conditions under which the putrefaction goes on, such as the temperature, the amount of oxygen present, the electrical conditions existing, and the duration of the process. Only the bacillus of typhoid fever (Eberth's bacillus), so far as is known, at least, can pro- duce the ptomaine typhotoxine, and the special bacterium of tetanus seems to be necessary in order to produce tetanine, a ptomaine which, when injected under the skin of an animal, causes tetanic convulsions. Brieger found that although the typhoid bacillus grew well in solu- tions of peptone, it did not produce any ptomaine; while from cultures of the same bacillus in beef tea he obtained a poisonous alkaloid. Fitz found that whilst the bacillus butyricus produces by its action on carbo- hydrates butyric acid, in glycerin it produces propylic alcohol. Brown has shown that while the mycoderma aceti converts ethylic alcohol into acetic acid, it converts propylic alcohol into propionic acid, and is with- out effect upon methylic alcohol, primary isobutylic alcohol, and amylic alcohol. Some bacteria will not multiply below a given temperature. 1^8 REPORT OF COMMITTEE ON DISINFECTANTS.
<Callout type="warning" title="Warning">Be cautious when using disinfectants; their effectiveness can vary greatly depending on the conditions.</Callout>
The lower temperature does not destroy the organism, but it lies dormant until the conditions are more favorable for its growth. Pasteur divided the bacteria into two classes, the aerobic and the an- aerobic. As the name implies, the former grow and thrive in the pres- ence of air, while the latter find their conditions of life improved by the exclusion of air. Therefore different ptomaines will be formed in de- composing matter freely exposed to the air, and in that which is buried beneath the soil or from which the air is largely excluded. Even when the same ferment is present the products of the putrefaction will vary with- in certain limits, according to the extent to which the putrefying mate- rial is supplied with air. The kind of ptomaine found in a given putrid substance will depend also upon the stage of the joutrefaction. Ptomaines are transition products in the process of putrefaction. They are tem- porary forms through which matter passes, while it is being transformed, by the activity of bacterial life, from the organic to the inorganic state. Complex organic substances, as muscle and brain, are broken up into less complex molecules; and so the process of chemical division goes on, until the simple and well known final products, carbonic acid gas, am- monia, and water, result. But the variety of combinations into which an individual atom of carbon may enter during this long series of changes is almost unlimited, and with each change in combination there is more or less change in nature. In one combination the atom of carbon may exist as a constituent of a highly poisonous substance, while the next combination into which it enters may be wholly inert. It was formerly supposed that putrefaction was simply oxidation, but the researches of Pasteur and others have demonstrated the fact that countless myriads of minute organisms are engaged constantly in trans- forming matter from the organic to the inorganic form.
Historical Sketch. It must have been known to primitive man that the eating of putrid flesh was liable to affect the health more or less seriously; and when he began his endeavors to preserve his food for future use, instances of poisoning from putrefaction must have multi- plied. However, the distinguished physiologist, Albert von Haller, seems to have been the first to make any scientific experiments concern- ing the effects of putrid matter upon animals. He injected aqueous ex- tracts of putrid material into the veins of animals, and found that death resulted. Later, in the eighteenth century, Morand gave an account of the symptoms induced by eating some poisonous meat. In the early part of the present century (1808 to 1814), Gaspard carried on similar experiments. He used as material the putrid flesh of both carnivorous and herbivorous animals. With these he induced marked nervous dis- turbances, as stiffness of the limbs, opisthotonos, and tetanus. Gaspard concluded from the symptoms that the poisonous effects were not due to carbonic acid gas or hydrogen sulphide, but thought it possible that am- monia might have part in their production. In 1820 Kerner published his first essay on poisonous sausage, which was followed by a second in 1822. At first he thought that the poisonous properties were due to a fatty acid similar to the sebacic of Thenard, and which originated during putrefaction. Later, he modified these views, and believed the poison to be a compound consisting of the sebacic acid and a volatile principle. This may be regarded as the first suggestion as to the probability of the development of a poisonous substance with basic properties in decom- posing matter.
In 1822 Dupre observed a peculiar disease among the soldiers under his care, who, during the very warm and dry summer of that year, were compelled to drink very foul water. Later, Magendie, induced by the investigations of Gaspard and the observations of Dupre, made many experiments, in which dogs and other animals were confined over vessels containing putrid animal matter, and compelled constant- ly to breathe the emanations therefrom. The effects varied markedly with the species of animal and the nature of the putrid material, but in some instances symptoms were induced which resembled closely those of typhoid fever in man. Leurent directed his attention to the chemical changes produced in blood by putrefaction, but accomplished nothing of special value. Dupuy injected putrid material into the jugular vein of a horse, and with Trosseau studied alterations produced in the blood by these injections. In 1850 Prof. Schmidt, of Dorpat, made some investigations on the decomposition products and volatile substances found in cholera stools; and two years later Meyer, of Berlin, injected the blood and stools of cholera patients into lower animals. In 1853 Stich made an important contribution on the effects of acute poisoning with putrid material. He ascertained that when given in sufficient quantity, putrid matter produced an intestinal catarrh with choleraic stools. Nervous symptoms, trem- bling, unsteady gait, and finally convulsions were also observed. Stich made careful post-mortem examinations, and was unable to find any characteristic or important lesion. Theoretically, he concluded that the putrid material contained a ferment which produced rapid decomposi- tion of the blood.
In 1856 Prof. Panum published a most important contribution to the knowledge of the nature of the poison present in putrid flesh. He first demonstrated positively the chemical character of the poison, inasmuch as he showed that the aqueous extract of the putrid material retained its poisonous properties after treatment which would insure the destruction of all organisms. His conclusions were as follows : (1) 'The putrid poison, contained in the decomposed flesh of the dog, and which is obtained by extraction with distilled water and repeat- ed filtration, is not volatile, but fixed. It does not pass over on distilla- tion, but remains in the retort.' (2) 'The putrid poison is not destroyed by boiling, nor by evapora- tion. It preserves its poisonous properties even after the boiling has been continued for eleven hours, and after the evaporation has been car- ried to complete desiccation at ioo°.' (3) ' The putrid poison is insoluble in absolute alcohol.
<Callout type="risk" title="Risk">Be aware that some disinfectants can be dangerous if not used properly; always follow safety guidelines.</Callout>
In 1856, Prof. Panum published a most important contribution to the knowledge of the nature of the poison present in putrid flesh. He first demonstrated positively the chemical character of the poison, inasmuch as he showed that the aqueous extract of the putrid material retained its poisonous properties after treatment which would insure the destruction of all organisms.
Key Takeaways
- Disinfecting agents' effectiveness varies based on the amount and type of material being treated.
- Mercuric chloride is effective in killing cholera spirillum but requires careful application to avoid health risks.
- Desiccation can be an effective method for sterilizing materials containing infectious organisms.
Practical Tips
- Always test disinfectants on a small, inconspicuous area before applying them widely to ensure they do not damage surfaces or fabrics.
- Use personal protective equipment when handling strong disinfectants like mercuric chloride to avoid skin and respiratory irritation.
- Regularly clean and disinfect frequently touched surfaces in your home or workplace to prevent the spread of germs.
Warnings & Risks
- Some disinfectants can be highly toxic if ingested; keep them out of reach of children and pets.
- Incorrect application of desiccation methods, such as leaving materials too wet for too long, can lead to mold growth or other issues.
- Be cautious when using chemical disinfectants in confined spaces; ensure proper ventilation to avoid inhalation hazards.
Modern Application
While the specific chemicals and techniques described in this chapter are outdated, the principles of effective disinfection remain relevant. Modern survivalists can apply these lessons by understanding the importance of proper sanitation methods and choosing appropriate disinfectants based on the type of contamination. Additionally, the study of ptomaines provides insight into how bacteria transform organic matter, which is crucial f