316 DR ALISON’S OBSERVATIONS ON 
carbon and hydrogen, as that which exists in the blood, or in the textures of ani- 
mals. As there is, in the whole of the ingesta of animals, a great excess of car- 
bon and hydrogen over their proportion to azote in albumen, and as oxygen is 
always present in the blood, it is quite possible that a part of the azote of the 
albumen taken in, may be thrown off in combination with portions of those other 
elements, by the bowels and kidneys, without entering into the textures; and — 
that the nourishment of the textures may be in part due to fresh albumen, formed 
in the animal body by help of oxygen from the lungs, and of azote taken in by 
another channel; just as we are nearly sure that part of the oil taken into an 
animal is often decomposed and thrown off, and that fresh fat is often formed 
from the starch or sugar of the ingesta. 
There is one mode, pointed out by Liesic, in which we can have no doubt 
that azote must be introduced into the blood of animals, independently of the al- 
buminous ingesta, viz., by the air which is contained in the water, and still more 
in the saliva, continually taken into the stomach. ‘ During the mastication of 
the food, there is secreted into the mouth, from organs specially destined to this 
function, a fluid, the saliva, which possesses the remarkable property of inclosing 
air in the shape of froth, in a far higher degree than even soap-suds. This air, by 
means of the saliva, reaches the stomach with the food, and there its oxygen en- 
ters into combination, while its nitrogen is given out through the skin and lungs.”* 
Now, what proof is there that the azote, thus believed to be set free in the 
stomach, is excreted, unchanged, by the skin and lungs? Is it not much more 
probable that it enters into fresh combinations in the prime vie and in the blood, 
and is only separated from the blood, when, by the agency of the oxygen of the 
air, acting, under the circumstances to be afterwards stated, with peculiar energy 
on some of the constituents of the blood, itis disjoined from its union with carbon 
and hydrogen. 
In fact, the azote thus set at liberty in the stomach, must be in circumstances 
almost exactly similar to those in which, according to the statements of MULDER 
and others, ammonia is formed from air, even by the help of inorganic matter ; still 
more when organic matter, although non-azotised, is present in a state of decom- 
position, or an analogous condition.+ ‘By all porous substances ammonia is pro- 
duced,—provided they are moist, are filled with atmospheric air, and are exposed 
to a certain temperature.” 
“¢ When reddened litmus paper is hung up in a bottle, filled with pure atmo- 
spheric air, and when pure iron-filings, moistened with pure water, are laid at the 
bottom, then the red litmus is quickly turned blue by the action of ammonia, 
formed from the nitrogen on the air, and the hydrogen of the decomposed water, 
the oxygen of which had combined with the iron. 
* Liepie’s Animal Chemistry, pp. 113-4. 
+ Mutpkr, p. 149, et seq. 
