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thus bring about its absorption in what might might be termed 

 a natural fashion. This objection can, however, be dismissed 

 (i) owing to the rapidity of the absorption which has been 

 observed, and (2) because the amount of enzyme left after the 

 cleansing of the intestine must be very small indeed. The 

 figures obtained by Heidenhain (I.e.) and Waymouth Reid (I.e.) 

 showed that the intestine could deal with quite large amounts 

 of serum in a comparatively short time. It is impossible to 

 understand how the trace of trypsin, supposed to be present, 

 could bring this about, more especially as trypsin does not 

 act by any means rapidly on this form of protein in its 

 native state. 



How then is the protein normally absorbed ? Protein food- 

 stuffs after ingestion are first of all acted on in the stomach 

 by the pepsin present ; here, however, under normal conditions 

 decomposition is not fully carried out. This gastric digestion 

 seems to aid the final action of the trypsin in some way other 

 than the mere mechanical aid given by rendering the more or 

 less solid masses of foodstuff suitable for the rapid attack of 

 the trypsin and other intestinal enzymes. Abderhalden and 

 Fischer 1 have shown that protein stuffs which have been 

 digested first by pepsin and then by trypsin, yield, in vitro 

 at least, a much smaller amount of polypeptide substance than 

 do the same proteins when they have been subjected to the 

 action of trypsin alone. Further, Abderhalden and Rona 2 

 have demonstrated, by feeding experiments on mice, that the 

 digest which arises from the combined action of pepsin and 

 trypsin has not the same power of preventing loss of nitrogen — 

 in other words, has not the same food value as the products 

 yielded by trypsin alone. On the other hand, from the experi- 

 ments of Czerny and others one might conclude that the 

 stomach is a quite unnecessary organ. They have shown that 

 animals from whom the stomach has been practically completely 

 removed can not only exist, but after they have accustomed 

 themselves to the new conditions can actually thrive. The 

 food from the stomach is passed on into the small intestine, 

 where it is more or less completely broken down by the action 

 of the trypsin into simpler bodies — into albumoses, peptones, 

 and bodies which no longer give the biuret reaction. The 



1 Abderhalden and Fischer, Zcit.f.physiol. Chem. 40, 1904, 215. 

 * Abderhalden and Rona, Zeit. f. physiol. Chem. 42, 1904, 528. 



