DEODORIZERS AND DISINFECTANTS. 
65 
sulphurous acid. The action of this compound will be best 
understood by the following diagram : 
2 A ~ ’ ■' ' ~ * ' 
If phosphuretted hydrogen were present, then would the 
change be analogous to the above ; all fetor being of course 
destroyed by the production of two well-known odourless 
bodies in both instances. 
But although for ages the fumes of burning sulphur have 
been employed as a disinfectant, yet objections have been 
raised to them on account of their unpleasantness. An ad- 
mirable mode of applying them is in the disinfecting powder 
invented by Mr. McDougall, which we have tried and found 
completely to answer all its intended purposes. Moreover, 
when it is mixed with the excreta of animals, a valuable 
manure is formed. We will let the inventor speak for him- 
self. In a lecture lately published by him he says : 
“ In order to a correct understanding of the subject, it is necessary to 
recollect that the gaseous emanations from fecal and other organic matters 
used as manures are sulphuretted hydrogen and phosphuretted hydrogen, 
either free or in combination with ammonia, and that the fertilizing ele- 
ments to be preserved are phosphoric acid and ammonia. 
“The agent by means of which we propose to remove these noxious 
bodies, and preserve the valuable ones, is a compound of two acids and two 
bases. The acids are sulphurous acid and carbolic acid , and the bases, 
magnesia and lime. These four exist in it as two salts, viz., sulphite of 
magnesia and lime and carbolate of lime . The action peculiar to each of 
these constituents of the disinfector I shall now explain. 
“ The only agent we know which will decompose the noxious emanations 
from putrescent excreta, or other animal offal, without exerting any detri- 
mental action upon those elements which we wish to preserve, is sulphurous 
acid. By it, the offensive smell of putrescent substances may at once be 
removed. Further than this, sulphurous acid has a conservative action, 
which is highly favorable to our object. It has a strong affinity for 
oxygen, and will not permit other substances in its presence to combine 
with oxygen, till its own affinity is satisfied. It thus exercises an influ- 
ence highly antiputrescent, besides decomposing the offensive compounds 
which have been already formed. 
“We have another guarantee, however, for the prevention of putrefactive 
fermentation ; this is the carbolic acid, which has the property of coagu- 
lating albuminous substances, and generally of preventing putrescence. As 
it is a liquid, oily compound, we combine it with lime, and are thus en- 
abled to dry it and reduce it to a powder, so rendering its application easy 
and simple. 
“ It only remains now that I explain the reason why we use magnesia 
in combination with the sulphurous acid. The reason is, that the com- 
pounds to be preserved are ammonia and phosphoric acid, and magnesia 
is the only available element which combines with them both and forms a 
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