CHEMICAL COMPOSITION OF THE HUMAN BODY. 13 



in the presence of water and an alkali, it is decomposed, with the assimi- 

 lation of the elements of water, into a fatty acid and glycerine. The fatty 

 acid combines with the alkali and forms an oleate, palmitate or stearate, 

 according to the fat used. A similar decomposition of the neutral fats is 

 said to take place in the small intestine during digestion. When thoroughly 

 mixed with pancreatic juice, the fats are reduced to a condition of emulsion, 

 a state in which the fat is minutely subdivided and the small globules held 

 in suspension. 



The Fatty acids combined with sodium, potassium' ami calcium, are 

 found as salts in various fluids of the body, such as blo6d, chyle, faeces, 

 etc. Phosphorized fats in nervous tissue, butyric acid in milk, propionic 

 acid in sweat, are also constituents of the body. 



The Fats are derived from the food, both animal and vegetable. They 

 are deposited in the form of small globules in the cells of the different 

 tissues, are suspended in various fluids, are deposited in masses in and 

 around various anatomical structures and beneath the skin. Independent 

 of the fat consumed as food, there is good experimental evidence that fat 

 is also produced within the animal body from a partial decomposition of 

 the albuminous compounds. Fat serves as a non-conductor of heat, gives 

 roundness and form to the body, and protects various structures from 

 injury. The fats are ultimately oxidized, thus giving rise to heat and 

 force, and are finally eliminated as carbonic acid and water. 



III. ORGANIC NITROGENIZED PRINCIPLES. 



ALBUMENS. C. O. H. N. S. P. 



Albumen. Myosin. Mucin. 



Albuminose. Protagon. Chondrin. 



Fibrin. Pepsin. Elastin. 



Casein. Pancreatin. Keratin. 



Ostein. Salivin. Globulin. 



The Albuminous compounds are organic in their origin, being derived 

 from the animal and vegetable world; they are taken into the body as 

 food, appropriated by the tissues, and constitute their organic basis ; they 

 differ from the non-nitrogenized substances in not being crystalline, but 

 amorphous, in having a more complex but just as definite composition, and 

 containing in addition to C. O. H., nitrogen, with, at times, sulphur and 

 phosphorus. The albumens possess characteristics which distinguish 

 them from all other substances : viz., a molecular mobility, which permits 

 isomeric modifications to take place with great facility; a catalytic influence, 

 in virtue of which they promote, under favorable conditions, chemical 

 changes in other substances: e.g., during digestion, salivin and pepsin 



