38 DISINFECTANT 



They show both mechanical and chemical action. The mechanical, when walor <>r ;:ir 

 removes, dilutes, or covers the septic bodies: the chemical, when porous bodies act as 

 conveyers of oxygen : or an union of both, when cold and heat prevent the mobility of 

 the particles. The action by oxidation causes a destruction of the offensive m 

 The other method is antiseptic. It is much to bo desired that all impurities shor.lt! l>e 

 got rid of by some of these methods, but especially by the air, the water, and the soil. 

 There are, however, conditions in which difficulties interfere with the action. Largo 

 towns may be purified by water, but what is to be done with the water which contains 

 all the impurity? If put upon land, capable of absorbing it, it is very soon disin- 

 fected, but on its way to the land it may do much mischief. It has been proposed to 

 disinfect it on its passage, and even in the sewers themselves; by this means t ho 

 town itself is freed from the nuisance, and the water may bo used where it is needed 

 without fear. This introduces artificial disinfectants. There are other cases when* 

 such are required ; when the refuse matter of a town is allowed to lie either in exposed 

 or in underground receptacles ; in this case a town is exposed to an immense surface 

 of impurity, and disinfectants would greatly diminish the evil, if not entirely remove 

 it. There are besides, special cases without end continually occurring, where impu- 

 rities cannot be at once removed, and where treatment with artificial disinfectants is 

 required. 



Artificial disinfectants which destroy the compound are of various kinds. Heat is 

 one of the most powerful. A putrid body, when heated so as to be deprived of all 

 volatile particles, cannot any longer decompose. It is however possible that the 

 vapours may become putrid, and if not carefully treated, this will happen. It was t lie- 

 custom of some of the wealthy among the ancients to burn the dead, and it is still the 

 custom in India ; but although the form is kept up amongst all classes, the expense is 

 too great for the poor. The bodies are singed, or even less touched by fire, and 

 thrown if possible into the river. This process has been recommended here, but the 

 quality of the gaseous matter rising from a dead body is most disgusting to our 

 physical, and still more to our moral senses, and the amount is enormous. It is of 

 course possible so to burn it, that only pure carbonic acid, water, and nitrogen, 

 shall escape, but the probability of preventing all escape is small enough to be deemed 

 an impossibility, and the escape of one per cent, would cause a rising of the whole 

 neighbourhood. To effect the combustion of the dead of a great city, such a large work, 

 furnished with great and powerful furnaces, would be required, that it would add one 

 of the most frightful blots to modern civilisation, instead of the calm and peaceful 

 churchyard where our bones are preserved as long at least as those who care for us live, 

 and then gradually return to the earth. In burning the dead some prefer to burn 

 the whole body to pure ash. This was the ancient method ; but it is highly probable 

 that the ashes which they obtained were a delusion in most cases. The amount of 

 ash found in the urns is often extremely small. The body cannot be reduced !< \\\\ 

 infinitesimal ash, as is supposed ; eight to twelve pounds of matter remain from an 

 average man when all is over. A second plan, is to drive off all volatile matter, and 1 e : ve 

 a cinder. This disgusting plan leaves the body black and incorruptible. It can never, 

 in any time known to us, mix with its mother earth, and yet it ceases at once to 

 resemble humanity in the slightest degree ; it will not oven for a long time assist us 

 by adding its composition to the fertility of the soil. The burning of bodies never 

 could have been general, and never can be general. Fire has only a limited use MS a 

 disinfectant. It cannot at present bo economically used in the daily disinfection of 

 the dejecta of animals, and is applied only occasionally, where the most rapid des- 

 truction is the most desirable, either because the substance has no value, or if is t.).. 

 disgusting to exist, or the products after burning are not offensive. There are. two 

 methods of using fire, charring or burning to ashes. The second is an act of 



Oxidation. This is effected either by rapid combustion called fire ; by slow com- 

 bustion, the natural action of the air; or by chemical agency, assisted l>y mechanical, 

 as in porous bodies. Slow oxidation in the soil is aprocess which is desirable f.,rmi^t. 

 offensive matters, and it would be well if we could bring it all into this condition; 

 the ammonia is preserved, or it is in part oxidised into nitric acid and water, both th^ 

 ammonia and nitric acid being food for plants. Sometimes this process is h; 

 by mixing up the manure with alkaline substances, raising it in heaps, and watering, 

 by this means forming nitrates, a process performed abundantly in warm countries 

 upon the materials of plants and animals, ami imitated oven in temperate regions 

 with success. This amount of oxidation destroys a good deal of the carbo' 

 substances, and leaves less for the land. It is only valuable when saltpetre is to be 

 prepared. 



One of the most thorough methods of oxidation, is by thn use of (he manganatefl or 

 permanganates. They transfer their oxy inic substances with great rapidity, 



and completely destroy them. They are therefore complete disinfectants. They 



