CHAPTER I 



THE PROTEINS AND THEIR DERIVATIVES 

 THE AMINO ACIDS 



THE PROTEINS 



The presence of nitrogen as a fundamental con- 

 stituent of protoplasm attests the supreme importance 

 of this element for the construction of living matter 

 and the continued existence of organized life. It is 

 well recognized, however, that all forms of nitrogen 

 are not equally available for the maintenance of 

 physiological rhythm. In support of this may be cited 

 the fact that although the animal organism is con- 

 tinually surrounded by an atmosphere rich in nitrogen, 

 little or none of this nitrogen can be utilized by the 

 body for nutritional purposes. The organism pos- 

 sesses discriminating powers and demands nitrogen 

 in a specific form, namely, such as that peculiar to 

 protein and its derivatives. Protein material con- 

 stitutes therefore an essential foodstuff and without 

 it life would be impossible for any considerable period 

 of time. "It is the chemical nucleus or pivot around 

 which revolves a multitude of reactions characteristic 

 of biological phenomena." 



