Page:The American Cyclopædia (1879) Volume VI.djvu/142

134 DISINFECTANTS which, while it did not prevent decay, still arrested all escape of disagreeable odors. The gases it retained indicated that it exerts an in- fluence in causing the decomposition of the exhalations, and the combination of their ele- ments to form new compounds with the oxy- gen of the air. Chlorine, which has for many years been in use in hospitals and other places exposed to noxious exhalations, acts as a powerful disinfectant by producing a chemical change in the injurious compounds, and also by arresting decay. It is generated by the decomposition of hydrochloric acid, which is effected by adding to it some black oxide of manganese. The chloride of lime, as it is com- monly known, is the usual medium for dis- tributing it, the gas being freely evolved on the exposure of the salt to the air. It is set free by the presence of any acid fames, and as carbonic acid is evolved in the decomposition of organic matters, the noxious effluvia them- selves provide one of the agents for their own disinfection. Vinegar or dilute sulphuric acid, however, added to the chlorinated lime, causes a more rapid evolution of the disinfecting gas. In consequence of the acrid nature of the va- por, it should bo used for fumigating rooms only when these are not occupied by invalids ; and the same may be said of the disinfecting solutions, as the hypochlorite of soda, of which chlorine is the active agent. The more pow- erful fumes of nitrous acid, which possess the highest disinfectant qualities, are liable to the same objection ; yet so important is their ap- plication regarded that Dr. Carmichael Smyth, who first proposed their use, received therefor from the British government the sum of 5,000. The unwholesome sulphuretted hy- drogen is decomposed by these fumes, as it is by chlorine, the sulphur being set free and the hydrogen uniting with the disinfectants. In combination with some of the metals, chlorine has been much used as a disinfectant, especially with zinc, in the aqueous solution of the chlo- ride of the metal, which is known as the dis- infecting fluid of Sir William Burnett. Its use is somewhat objectionable, from its poisonous qualities. The same compound is advantage- ously applied to arresting dry rot in timber. Chloride of manganese is an efficient salt of similar properties, and, being the refuse of chloric manufacture, may be cheaply pro- cured. Chloride of aluminum, under the pop- ular name of chloralum, has recently come into use. The action of iodine is similar to that of chlorine, and more powerful. Its application is simple. The solid substance, exposed to the air in a plate, will disengage at ordinary tem- peratures sufficient vapor to exert a chemical action on deleterious organic compounds. Ni- trate of lead has been recommended for its dis- infectant properties, particularly in the solution known as Ledoyen's disinfecting fluid. It cor- rects the fetid odors of sulphuretted hydrogen and sulphurvt of ammonium by decomposing those compounds, but it has no antiseptic prop- erties, and is objectionable on account of its cost and poisonous nature. Sulphate of iron, which is used for the cleansing of sewers, drains, and soil pipes, depends for its efficacy upon a similar action, and upon its deoxidizing power. The permanganate of potassa is, under certain circumstances, an excellent disinfectant and deodorizer, readily parting with its abun- dant oxygen; but it is not volatile, and cannot be brought into efficient contact with larjre quantities of air, so that its action in purifying the atmosphere is insignificant. For washing dirty and decomposing surfaces, and for the disinfection of fluids, as bilge water, it has been found very effective. Sulphurous acid, in- cluding the sulphites and hyposulphites, which easily disengage it, is an exceedingly active substance in several ways; it is a deoxidizer, and has besides the power of destroying life in the lower organisms. Sulphurous acid may be generated by burning sulphur in the apartment to be disinfected, care being taken to remove anything which might be bleached by its ac- tion. It has been found, however, that al- though of 1 per cent, of sulphurous acid in the atmosphere is sufficient to prevent the action of yeast as a ferment, yet to of 1 per cent, is not enough to destroy colors. It cannot be conveniently used in inhabited rooms, on account of its irritant properties ; although some physicians who have used it consider that its power of producing bronchial irritation has been exaggerated, and that pa- tients may become well accustomed to it. The sulphites and hyposulphites may be used for th deodorization of stables and manure .heaps ; for this purpose they have the advantage of add- ing to the fertilizing value of the substances acted upon, by retaining the phosphoric acid and ammonia. These salts have been used as medicines for the purpose of destroying a hy- pothetical ferment in the blood. Carbolic acid and creosote are disinfectants which have been much used of late. They prevent putrefaction by killing the microscopic organisms that ac- company this process. They have, however, but little power in preventing the action of emulsine on amygdaline, or diastase on saliva or starch ; from which it may be inferred that the estimate of their action upon other fermen- tations has been somewhat exaggerated. Car- bolic acid may be employed by vaporizing it from a hot plate or brick, by scattering a spray of its solution through the air and upon the walls, by placing open dishes filled with the acid or with carbolate of lime in localities to be disinfected, or by using dilute solutions to wash floors, &c. Its use in the surgical wards of hospitals has been said to diminish the mor- tality from infectious diseases, such as erysipelas and pyemia. Dr. Sansom has shown that in order to purify the atmosphere properly, and prevent the development of fungi, bacteria, and vibriones, and hypothetically of disease germs, it is necessary that the disinfectants should be volatile, as in the case of iodine and