230 PHYSIOLOGICAL CHEMISTRY. 



found that the absorption of proteids from the intestine was not 

 influenced thereby, and from this concluded that the proteids as 

 well as the other nutritive bodies soluble in water pass directly 

 into the blood through the walls of the intestinal capillaries. If 

 this were the case, then we might expect to find peptone in solution 

 in the blood during or after digestion. This, however, is not the 

 case. ScHMiDT-MtJLHEiM and HOFMEISTER found only traces of 

 peptone in serum or blood, and according to NEUMEISTER it does 

 not occur even as traces. Chyle does not contain any peptone. 



Then where does the peptone which is absorbed from the 

 intestine remain ? If peptone in solution is introduced into the 

 circulating blood, it is quickly eliminated therefrom with the urine 

 (PLOS'Z and GYERGYAI, HOFMEISTER, SCHMIDT-MULHEIM). The 

 same happens also after injecting peptone subcutaneously. Nor- 

 mal urine does not contain any peptone, and the absence of this 

 body in the blood after digestion cannot be explained by assuming 

 that it is eliminated by the kidneys, Since the peptone introduced 

 into the blood is quickly eliminated by the kidneys, while the 

 peptone formed in the intestine does not pass into the urine, it 

 may perhaps be thought that this peptone is retained normally by 

 the 'liver and is absorbed, and only that peptone which finds its 

 way into the circulating blood by evasion from this organ passes 

 into the urine. This supposition, however, is untenable. NEU- 

 MEISTER has investigated the portal blood of rabbits in whose 

 stomachs large quantities of albumoses and peptones had been 

 introduced, and found therein only traces of the body in question. 

 He has also shown that when we supply the liver of a dog with 

 the portal-blood peptone (ampho-peptone), this is not retained by 

 the liver but is eliminated with the urine. Peptone seems to pass 

 neither into the blood nor the chylous vessels, but to be changed 

 in some way by the walls of the intestine. HOFMEISTER, according 

 to whom the walls of the stomach and the intestine are the only 

 parts of the body in which peptones occur constantly during diges- 

 tion, has also made the observation that peptone (at the tempera- 

 ture of the body) after a time disappeared from the excised but 

 apparently still living mucous coat of the stomach. Peptone seems 

 to undergo a change in the mucous membrane of the digestive 

 canal, and the following observation of LUDWIG and SALVIOLI 



