DISINFECTANT 39 



destroy the odour of putrid matter rapidly, and oxidise sulphuretted hydrogen, and 

 phosphuretted hydrogen, as well as many purely organic substances having offensive 

 smells. As they do this by oxidation at a low temperature, they are the mildest form 

 of the destructive disinfectants, and their application to putrid liquids of every kind 

 gives most satisfactory results. The quantities treated at a time should not be great, 

 and the amount of material used must be only to the point of stopping the smell, or at 

 least not much more, because both pure and impure matter act on the manganates, and 

 an enormous amount of the material may be used in destroying that which is not all 

 offensive. The manganates do not prevent decay from beginning again. Their use 

 has been patented by Mr. Condy. A similar action takes place with various high 

 oxides and other oxides which are not high. Sometimes, however, a deleterious gas 

 is produced as a secondary result by oxidation, as when sulphuric acid in the sulphates 

 oxidises organic matter, allowing sulphuretted hydrogen to escape. In this case it is 

 highly probable that a true disinfection takes place, or a destruction of the putrid 

 substance, and all offensive purely organic substances ; still the amountof sulphuretted 

 hydrogen given off is of itself sufficiently offensive and deleterious, but not properly 

 speaking an infectious or putrid gas, although an occasional accompaniment. 



Nitric acid is another agent of destruction or oxidation, although it has qualities 

 which might cause it to be ranked amongst those which prevent the decomposition by 

 entering into new combinations. But properly speaking, it is not nitric acid which is 

 the disinfectant of Carmichael Smyth, but nitric oxide, which is a powerful oxidiser, 

 and most rapidly destroys organic matter. For very bad cases, in which gaseous 

 fumigation is applicable, nothing can be more rapid and effective in its action than 

 this gas. Care must be taken that there is no one present to breathe it, as it has a 

 powerful* action on the lungs, killing without due warning, and care must be taken that 

 metallic surfaces which are to be preserved clean, be well covered with a coating of 

 varnish. This was used with great effect in ships and hospitals for some years, begin- 

 ning with 1780, and so much good did it do, that the Parliament in 1802 voted Dr. 

 C. Smyth a pension for it. Guyton-Morveau was vexed at this, and wrote an interest- 

 ing volume concerning his mode of fumigating by acids ; but in reality acids alone 

 are insufficient, and his favourite muriatic acid has no such effect as nitrous fumes, 

 which so readily part with their oxygen. On the whole, nitrous fumes are too danger- 

 ous for general use. 



Chlorine is another destructive agent, and its peculiar action may be called an 

 oxidation. When used as a gas, it has a great power of penetration, like nitrous fumes, 

 and stops all putrefaction. It has a more actively destructive power than oxygen 

 alone, even when its action is that of oxidation only. It decomposes compounds of 

 ammonia and organic substances containing nitrogen into water and nitrogen, and as 

 putrefactive matter is united with, or composed partly of nitrogen, it destroys the very 

 germ of the evil. By the same power it destroys the most expensive part of a manure, 

 the ammonia. It cannot therefore be used where the offensive matter is to be retained 

 for manure. When chlorine is united with lime or soda, it may be used either as a 

 solution or a powder. This latter acts as the gaseous chlorine, but the power of 

 destroying ammonia is greater. As a liquid, it acts too rapidly ; as a solid, the 

 chloride of lime soon attracts moisture and soon loses its power. Some people use 

 the chloride of lime as a source of chlorine ; they pour sulphuric acid on it, and so 

 cause it to give out chlorine, which escapes as a gas, and acts as aforesaid. Too much 

 is given out at first, too little at last. It is said to have increased the lung diseases 

 at hospitals, where it was much used in Paris. When only a minute quantity of gas is 

 given out, as at bleach works, it certainly causes a peculiar freshness of feeling, and 

 the appearance of the people is much in its favour, nor has it ever there been known 

 to affect the lungs. For violent action, in cases of great impurity, it is a great dis- 

 infectant, and to be preferred to nitrous fumes, probably causing a less powerful action 

 on tho lungs : at least, it gives good warning. Mixed with alum, without ammonia, it 

 gives off chlorine slowly. Eau dejavelle is a chloride of potash used in Paris. Mr. 

 Daniel Stone uses muriatic acid with a small crystal of chlorate of potash to give out 

 a slight chlorine vapour slowly. 



Sometimes oxygen, or at least air, is used alone, to remove both colour and sinell, 

 oils having it pumped into them. Sometimes acids alone are used for disinfection. 

 As putrid compounds contain ammonia or organic bases, they may be removed, or at 

 least they may be retained in combination, and in this way restrained from further 

 evaporation. This seems to be the way in which muriatic acid acts, and all other 

 merely acid agents. This acid, so much valued at one time, is now entirely disused, 

 as it ought to be, because it is exceedingly disagreeable to breathe, and destructive of 

 nearly all useful substances which it touches, being at the same time a very indirect 

 disinfectant. Acids poured on putrid matters, no doubt destroy the true putrefaction, 

 but they cause the evolution of gases exceedingly nauseous, and of course unwholesome, 



