THE CHEMICAL CONSTITUTION OF THE ANIMAL BODY. 1387 
which an internal skeleton would be useless, a defect well illus- 
trated by that disease of the bones known as rickets, in which 
the lime-salts are insufficient. It is manifest that there may be 
avery great variety of classifications of the compounds found 
in the animal body according as we regard it from a chemical, 
physical, or physiological point of view, or combine many 
aspects in one whole. The latter is, of course, the most correct 
and profitable method, and as such is impossible at this stage 
of the student’s progress; we shall simply present him with the 
following outline, which will be found both simple and com- 
prehensive.* The subject of Animal Chemistry will be found 
treated in detail in the Appendix. 
CHEMICAL CONSTITUTION OF THE BODY. 
Such food as supplies energy directly must contain carbon 
compounds, 
‘Living matter or protoplasm always contains nitrogenous 
carbon compounds. 
In consequence, C, H, O, N, are the elements found in great- 
est abundance in the body. 
The elements S and P are associated with the nitrogenous 
carbon compounds; they also form metallic sulphates and phos- 
phates. 
Cl and F form salts with the alkaline metals Na, K, and the 
earthy metals Ca and Mg. 
Fe is found in hemoglobin and its derivatives. 
Protoplasm, when submitted to chemical examination, is 
killed. It is then found to consist of proteids, fats, carbohy- 
drates, salines, and extractives. 
It is probable that when living it has a very complex mole. 
cule consisting of C, H, O, N, 8, and P chiefly. 
PROXIMATE PRINCIPLES. 
ds Proteids. 
ft Onpante (a) Nitrogenous. i Certain crystalline bodies. 
: (b) Non-nitrogenous. | Ne as 
Mineral salts. 
2. Inorganic. 1 eter 
SaLts.—In general, the salts of sodiwm are more characteris- 
tic of animal. tissues and those of potassium of vegetable tissues. 
* Taken from the author’s “ Outlines of Lectures on Physiology,” W. Drysdale 
& Co., Montreal. 
