292 PHYSIOLOGY CHAP. 



It has been stated that the proteoses and peptones can be, 

 synthetised into serum-albuinin in the intestine, and also in the 

 stomach, l>y simple contact with the living epithelial cells, i.e. 

 previous to absorption. Von Ott (1883) observed in the abdominal 

 and intestinal cavity of recently killed rabbits, as also in the 

 stomach of living dogs, that serum-albumin can be formed after 

 introducing commercial peptone (which consists largely of 

 proteoses). To prove that this was a true regeneration into 

 serum-albumin he employed not only chemical reagents but 

 also a physiological reagent, i.e. the frog's heart, excised and 

 attached to Kronecker's apparatus. The heart did not beat 

 when filled with a solution of proteoses or peptone, and recom- 

 menced its beat when filled with the same solution regenerated 

 by contact with the gastric or intestinal mucous membrane. 

 Von Ott's results were confirmed and extended by Julia Brinck 

 and N. Popoff in Kronecker's laboratory (1889); they used 

 Vella's loop of intestine for the regeneration of the proteose and 

 peptone. 



That the synthetic reconstruction of the coagulable protein is 

 the work of the living epithelial cells is proved by the fact that 

 the phenomenon does not occur when proteoses and peptone are 

 brought into contact with the mucous membrane of the intestine 

 or stomach after the death of the cells (20 min. after killing the 

 animal). In this case (if the body is placed in a chamber 

 regulated at 37-40 C.) auto-digestion of the mucous membrane 

 may take place, but there is no synthesis of the proteoses and 

 peptone introduced. J. Brinck further found in the contents of 

 the intestine a micrococcus capable of the same synthetic function 

 as the epithelial cells, to which she gave the name of Micrococcus 

 restituens. 



Granting the accuracy of these interesting phenomena, they do 

 not seem to us adequate to prove that proteoses and peptones 

 are regenerated into serum-albumin by simple contact with the 

 living epithelia, previous to absorption. If this be admitted, 

 there can be no advantage in the proteolytic process, which 

 facilitates or accelerates absorption. It seems to us more logical 

 and simpler to assume that part of the protein formed synthetically 

 by the cytoplasm of the epithelial cells is poured back into the 

 intestine with the succus entericus or gastric secretion from the 

 glandular crypts of the intestine and stomach respectively. It is 

 now known as a fact that succus entericus always contains a 

 certain amount of protein (0*5 per cent according to Quincke, 

 according to Thiry, Pregl, and others a somewhat larger proportion). 

 And Mine. Schumowa-Simanowskaia demonstrated that pure 

 gastric juice obtained from a gastric fistula with sham feeding 

 always contains a certain amount of protein (013-0-18 per cent). 

 We regard it as probable that the coagulable protein found by 



