88 THE AMINO ACIDS 



KASSOWITZ 



Kassowitz in 1904 put forth the view that it was 

 scarcely probable that a substance would serve both as 

 reconstructive material for disintegrated cells and as 

 a source of energy. According to his ideas food pro- 

 tein is not merely transformed into living protoplasm 

 by some obscure rearrangement but there is an actual 

 synthesis with fat and carbohydrate to form living 

 bioplasm. Like Pfliiger he adopts the view that only 

 "organized" protein is oxidized. 



In metabolism there are two types of protoplasmic 

 disintegration: the inactive, whereby the protoplasm 

 formed from food protein during rest is immediately 

 changed or broken down into non-nitrogenous storage 

 materials (glycogen and fat) and urea; the active, by 

 which under the influence of stimuli which induce 

 muscular contractions, the protein nucleus of the dis- 

 integrating protoplasm molecule is left intact so that 

 it may serve for the resynthesis of protoplasm with 

 fresh non-nitrogenous compounds. (Mendel.) 



SPECK 



In the theory of Speck (1903) the view is held that 

 two forms of protein exist but that the catabolism of 

 organized protein is quite different from that of the 

 unorganized protein. That portion of food protein 

 (unorganized) not employed for the building up of 

 living tissue, is split into two portions, first, a nitro- 

 genous part, which is rapidly converted into urea, 



