LECTURE XI. 



ALBUMINS OR PROTEINS. 

 V. 



DECOMPOSITION OF PROTEINS IN THE TISSUES. THE END-PRODUCTS 

 OF ALBUMIN METABOLISM. 



ACCORDING to our present conception of the digestion and assimilation 

 of albuminous substances, we must assume that the different proteins of 

 our food are converted into the albuminous bodies of the plasma. In this 

 form the individual cells obtain the nitrogenous material which is abso- 

 lutely necessary for its maintenance, and, from our knowledge of 

 metabolism during fasting, 1 we must conclude that the cells themselves 

 give up their albumin only in this form to the blood for further transpor- 

 tation. We know as little about the manner in which the cells produce 

 their albumin from the proteins of the blood as we do of the reason 

 why the animal organism, under all conditions, requires such relatively 

 large amounts of albumin for the proper maintenance of its corporal 

 existence. In this connection it is especially noteworthy that the growing 

 nursling consumes as much albumin, proportionately, as does the fully 

 developed organism. E. Feer 3 gives 951 grams as the daily quantity of 

 milk consumed by a boy 29 to 30 weeks old, and weighing 8.23 kilograms. 

 This amount would contain 15.2 grams albumin, 32.3 grams fat, 58.0 

 grams sugar, and 1 . 9 grams ash. At this rate a grown-up person weighing 

 70 kilograms would consume daily: 



Albumin 129 grams 



Fat 275 " 



Sugar 494 " 



Ash 16 " 



The following values have been found actually to be the average food 

 requirement of an adult: 



Albumin 118 grams 



Fat 56 " 



Sugar 500 " 



1 See Lecture on Metabolism. 

 1 Jahrbuch f. Kinderheilkunde, X. F. 42, 195, 196. 



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