78 SCIENCE -PROGRESS 
thus bring about its absorption in what might might be termed 
a natural fashion. This objection can, however, be dismissed 
(1) 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 (/.c.) and Waymouth Reid (/.c.) 
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! have shown that protein stuffs which have been 
digested first by pepsin and then by trypsin, yield, 7 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? 
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, Zezt. f. physiol. Chem. 40, 1904, 215. 
* Abderhalden and Rona, Zez?t. f. physiol. Chem. 42, 1904, 528. 
