14 HUMAN PHYSIOLOGY. 



The Fatty acids combined with sodium, potassium and calcium, are 

 found as salts in various fluids of the body, such as blood, 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. 



ALCOHOLS. 



Glycerine. Cholesterine. Alcohol. 



Glycerine is chemically a triatomic alcohol in combination with the neu- 

 tral fats of the body. During pancreatic digestion it is set free. It is 

 supposed by many physiologists to be directly concerned in the production 

 of glycogen. Cholesterine is a crystallizable substance largely present in 

 the bile, though it is found in other fluids and solids. It is supposed to be 

 a waste product of nervous matter. Alcohol has been found in the urine. 

 It is supposed to be the result of an alcoholic fermentation in the intestine. 



III. ORGANIC NITROGENIZED PRINCIPLES. 



The nitrogenized or proteid 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 proteids 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 cause starch 

 and albumin to be transformed into sugar and albuminose respectively. 

 Different proteids possess varying proportions of water, which they lose 



