326 DR ALISON’S OBSERVATIONS ON 
seems evidently to denote that it is most probably formed from the elements of 
albumen, by a farther separation of carbon and hydrogen; aided by the agency of 
the oxygen of the air. Lresie seems to consider it as certain, that this separa- 
tion must be from the elements of albumen, and, therefore, that gelatin can only 
be formed from albumen ; but it is possible, also, that it may take place from 
the elements of starch with ammonia, oil being formed at the same time. 
If we take the numbers given by MuLpER as representing the composition of 
gelatin, this appears very distinctly. Thus, 
C N H O 
To starch, oa UO “LUU 
Add ammonia, A) 6 18 nhs 
From this subtract, 
Elements of gelatin, 39 6 30 15 
co) ee 88 85 
And again, 5 equivalents of fat, 60... 50 5 
+ Sala 38 80 
which is exactly 21 equivalents of carbonic acid with 38 of water, excreted by 
the skin and lungs. 
The “ tritoxide of protein,” lately so fully considered by Mu1.DER, approaches 
so nearly in its properties to gelatin, that we may presume its formation will de- 
pend on nearly the same conditions; and accordingly we find, that it may be 
formed from albumen by the long-continued application of heat, air, and water ; 
and that it is formed in large quantities in inflamed parts, where the stagnation 
of arterial blood (carrying oxygen) and the increased temperature plainly indi- 
cate that an increased application of oxygen is going on. 
But as there is a remarkable discrepancy of statement as to the chemical rela- 
tion of gelatin to the albuminous compounds, we must regard the precise na- 
ture of the change effected in this department of the animal economy as some- 
what doubtful. 
In thus attempting to trace the nature of the processes, wherever they may 
be carried on, by which carbon, nitrogen, hydrogen, and oxygen, uniting with 
other elements in smaller proportion, fall into the combinations which constitute 
the animal textures, and in attempting likewise to assign the province of the 
vital affinities in these processes, we must admit very material deficiency of inm- 
formation. We do not perceive, for example, how it should happen that the amy- 
laceous matter, which forms the greater part of the ingesta of so many animals, 
