ALBUMINS OR PROTEINS. 243 



through administrations by the mouth, as well as by subcutaneous injec- 

 tions. We know to-day that this synthesis, which at that time created 

 much excitement on account of the fact that it was the first instance in 

 which a synthetic process had been shown to take place in the animal 

 organism, is not unique. Thus, R. Cohn l found that naphthoic acid 

 administered to rabbits and to dogs reappeared in the urine as naphturic 

 acid. Its formation is exactly analogous to that of hippuric acid: 



CioH 7 .COOH + NH 2 .CH 2 .COOH = Ci H 7 .CO.NH.CH 2 .COOH + H 2 O 

 Naphthoic acid Glycocoll Naphturic acid 



Salicylic acid unites with glycocoll in the same manner. 2 Hydroxy- 

 hippuric acid is formed: 



OH.C 6 H 4 .COOH + H 2 N.CH 2 .COOH = OH.C 6 H 4 .CO.NH.CH 2 .COOH 



Salicylic acid Glycocoll Hydroxyhippuric acid 



+ H 2 O 



It is also interesting to note that alkylated benzoic acids, for instance, 

 toluic acid, 3 likewise unite with glycocoll, reappearing as alkylated hippuric 

 acids : 



CH 3 .C 6 H 4 .COOH + NH 2 .CH 2 .COOH 



Toluic acid Glycocoll Toluric acid 



+ H 2 



Phenylacetic acid similarly appears in the urine as phenaceturic acid: 4 

 C 6 H 5 .CH 2 .COOH + NH 2 .CH 2 .COOH = C 6 H 5 .CH 2 .CO.NH.CH 2 .COOH 



Phenylacetic acid Glycocoll Phenaceturic acid 



+ H 2 



We have already seen, when discussing glucuronic acid, which plays a 

 role in the animal organism very analogous to that of glycocoll, that the 

 cells are able to adapt compounds, which of themselves would not unite 

 together, partly by oxidation, partly by reduction, and sometimes by both 

 methods. Thus, toluene is first converted into benzoic acid and then 

 united to glycocoll. Ethyl- and propylbenzenes are changed in the same* 

 manner. 5 Xylene is likewise oxidized to toluic acid. It is interesting to 

 note that aldehydes are oxidized to acids; as an example we will cite 



1 Z. physiol. Chem. 18, 112 and 119 (1894). 



2 Bertagnini: L. Ann. 97, 248 (1856); Z. physiol. Chem. 1, 244 and 253 (1877-78). 



3 Schultzen and Naunyn: Du Bois' Arch. 1867, 352. 



4 E. and H. Salkowski: Z. physiol. Chem. 7, 161 (1882-83); 9, 229 (1885). 



5 M. Nencki and P. Giacosa. ibid. 4, 325 (1880). 



