UTILIZATION OF PROTEID AND NON-PROTEID NITROGEN 33 



Such a view as is tentatively presented here is certainly in 

 harmony with the results of Loewi (1902) Abderhalden and others 

 who in elaborate investigations have shown that animals like the 

 dog may be maintained in nitrogenous equilibrium for long periods 

 of time when fed on a diet in which all protein material had been 

 replaced by the products of prolonged digestion of proteins. 

 These experiments imply that the cleavage products of the pro- 

 teins are resynthesized in the animal body. According to Abder- 

 halden no cells can directly assimilate and utilize foreign food 

 material. Complex nitrogenous food material must be prepared 

 for the cell through enzyme action. This breaking down and the 

 reconstruction of food are just as necessary as it is to reduce a 

 church to the very bricks which constitute it before it can be 

 converted into a school-house. This may perhaps apply to the 

 bacterial cell as well as in the field of animal cell nutrition. 



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