ADVANCED PHYSIOLOGY 



THE CHIEF CHEMICAL COMPOUNDS IN THE BODY 



If the materials used in building a city block were chemi- 

 cally analyzed, many of the elements found would be the 

 same as those present in the body. But when we talk about 

 the construction of a building, we never mention the chemi- 

 cal elements of which it is composed; we speak rather of 

 the compounds of these elements. Beams, piping, windows, 

 chimneys, furnaces, flooring and doors are all parts of the 

 building, but they can be roughly classified as made of wood, 

 iron, brick or stone. Similarly, in speaking of our bodies, 

 mention is seldom made of the chemical elements in them, 

 but of the combinations in which the elements most fre- 

 quently occur. 



There are three compounds that are of supreme import- 

 ance in living animals. They constitute almost all the 

 essential materials in our bodies. Since they are also the prin- 

 cipal constituents of our foods, they are called food stuffs. 

 These compounds are: (1) proteids, (2) carbohydrates and 

 (3) fats. Water and salts are also necessary. 



Proteids (Albumen, Myosin, Gluten, Casein, Legumen,Fibrin). 

 Proteid is made up chiefly of four elements: carbon, hydrogen, 

 oxygen and nitrogen, though sulfur and phosphorus are 

 present in small quantities. Proteid occurs in all animal and 

 vegetable organisms. For example, in the human body 

 proteid comprises 38.3% of the lens of the eye, 16% of the 

 muscles, 12% of the liver, 9% of the blood. These percent- 

 ages are not so small as they seem, since the greater part 

 of all tissues is water. The human body, taken as a whole, 

 is nearly 67% water, and the proteids form a large proportion 

 of the rest. 



Proteids as Tissue Builders. The proteid which the body 

 contains must either be obtained directly in foods or be made 

 from them. Now the body is quite unable to make proteid; 



