246 LECTURE XI. 



The question arises, What has become of the large amount of glutamic 

 acid? It is possible that it was completely disintegrated in the intes- 

 tine. This phenomenon may perhaps indicate the reason for the marked 

 increase in the amount of ammonia in the blood of the portal vein during 

 digestion. We might, however, assume that the glutamic acid was con- 

 verted into other amino acids and utilized in the synthesis of albumin. 

 We are unable to form a definite opinion. It is important, however, to 

 point out the possibility of such transformations, because the conclusion 

 has been drawn from the considerable amount of glycocoll which can be 

 withdrawn from the organism by means of benzoic acid, that the breaking 

 down of all the amino acids to urea passes through the glycocoll stage. 1 

 We are not justified in making any such assumption. There is no founda- 

 tion for it. It is far more probable that the organism in any given case 

 utilizes its albuminous substance richest in glycocoll, or, in case of neces- 

 sity, forms glycocoll from other amino acids. It must not be forgotten 

 that benzoic acid is a poison to the cells, causing an increase in the dis- 

 integration of albumin, thus leading to a direct increase in the amount 

 of glycocoll. We must also notice another possible source of glycocoll. 

 We shall soon see that the animal organism is able, to a marked degree, to 

 decompose uric acid. It is assumed, to be sure without an entirely satis- 

 factory proof, that glycocoll is formed as a decomposition product. The 

 amount of this amino acid thus formed is necessarily small among 

 mammals. Finally, we must consider the possibility of glycocoll being 

 produced synthetically, for instance, from ammonia and acetic acid. We 

 have, to be sure, not yet succeeded in detecting such a synthesis. 2 



All of the benzoic acid administered is not changed into hippuric acid. 

 A part is excreted as such, and another portion cannot be traced, evidently 

 being transformed in some unknown manner. 



The next question is, In which organ is the hippuric acid produced? 

 G. v. Bunge and O. Schmiedeberg 3 studied first of all the livers of frogs. 

 These survive the extirpation of the liver very well indeed, and live for 

 3 or 4 days after the operation. They formed hippuric acid when benzoic 

 acid was introduced into the dorsal lymph sac, and particularly large 

 amounts when glycocoll was added at the same time. Hippuric acid has 

 never been obtained from the organisms of frogs or their excretions with- 

 out the previous administration of benzoic acid. The liver of the frog is, 

 therefore, not the only organ in which the benzoic acid unites with glycocoll, 

 if, indeed, the liver participates at all in this synthesis. 



Bunge and Schmiedeberg next tested the kidneys to see if they were 

 able to produce hippuric acid from benzoic acid and glycocoll. They 



1 W. Wiechowski: loc. cit. 



2 R. Cohn: Arch. exp. Path. Pharm. 53, 435 (1905). 



3 Arch. exp. Path. Pharm. 6, 233 (1877). 



