130 THE AMINO ACIDS 



sis tryptophane, unquestionably one of the most impor- 

 tant of the amino acids, is destroyed. The proof that 

 herein lies the true explanation was furnished by 

 Abderhalden and Frank, who succeeded in maintaining 

 dogs in nitrogenous equilibrium on meat completely 

 hydrolyzed by acid to which had been added a small 

 amount of tryptophane. 



After the demonstration that the nitrogenous nutri- 

 tive requirements of the organism can be supplied by 

 a mixture consisting of the products of hydrolysis, 

 whether by acids or enzymes, an attempt was made 

 by Abderhalden to support a dog in nitrogen equilib- 

 rium on an artificial mixture of amino acids to which 

 were added carbohydrate and fat. The successful out- 

 come of the investigation led Abderhalden to declare 

 that the animal organism is capable of forming all 

 the tissue constituents out of the simplest derivatives 

 of the proteins. Inasmuch as carbohydrate and fat 

 may be prepared synthetically, as may some of the 

 amino acids, the problem of the artificial production 

 of foodstuffs is solved according to Abderhalden, 

 who says that such a possibility is limited only by the 

 question of sufficient funds. From these observations 

 it becomes evident that mixtures of amino acids are 

 fully capable of supplying the nitrogenous needs of 

 the organism when applied to the lower animals. An 

 opportunity was afforded Abderhalden and his co- 

 workers to extend this type of investigation to man. 

 A boy with a stricture of the oesophagus on whom 

 gastrotomy had been performed was the subject. To 



