CERTAIN DERIVATIVES OF THE PROTEIDS. 307 



Further, on saturating the urine with ammonium sulphate 

 under appropriate conditions for removal of all the gelatoses, 

 and testing the filtrate by the biuret test, a distinct reaction 

 for true gelatin-peptone was obtained. Five and a half hours 

 after the injection the urine still contained an appreciable 

 amount of gelatose. After injection of deuterogelatose the 

 urine was likewise found rich in gelatin-peptone, while some 

 unaltered gelatose was also found. This excretion of gela- 

 toses through the urine as gelatoses and gelatin-peptone was 

 quite marked, and we were able to separate from such urines 

 several grams of fairly pure gelatose, thus showing that the 

 elimination through this channel was not inconsiderable. If 

 it is true, as suggested by Neumeister, that the hydration of 

 a primary proteose to secondary proteose and the hydration 

 of the latter to true peptone in these cases is due to the 

 presence of pepsin in the kidneys acting in conjunction with 

 acid temporarily present, then our results testify to the ex- 

 treme vigor of such action, and indirectly suggest the pres- 

 ence of considerable active enzyme. Whether this hydrolytic 

 action is truly due to the presence of an enzyme our results 

 afford no answer. In this connection it will be remembered 

 that Hofmeister* observed that when amphopeptone was in- 

 jected subcutaneously, four-fifths of the substance appeared in 

 the urine unaltered. Neumeister f likewise noted that ampho- 

 peptone was excreted as such through the urine. In a paper 

 from this laboratory,^ however, attention was called to the 

 fact that peptone formed through the action of papain was 

 much less markedly eliminated through the urine than deutero- 

 albumose ; this statement being based upon the much weaker 

 biuret reaction given by the urine. In conformity with this 

 observation we have noted in the present experiments with 

 hemipeptone and gelatin-peptone that after the intravenous 

 injection of these substances their presence in the urine could 



* Hofmeister, Zeitschr. f. physiol. Chem., 1881, v, p. 131. 

 t Neumeister, Zeitschr. f. Biologie, 1887, xxiv, p. 287. 

 t Chittenden, Mendel, and McDermott, Amer. Jour. Physiol., 1898, i, 

 p. 276. 



