356 ACTIVITY OF THE WALL OF THE ALIMENTARY CANAL. 



Peptones have an endosmotic equivalent, more than four times 

 smaller than that of dextrose. They can be rapidly absorbed, on 

 account of their ease of diffusion and filtration. Absorption takes 

 place through the blood-vessels, unless excessive amounts are present in 

 the intestine, as after ligation of the thoracic duct, ingested proteids are 

 as well, absorbed as under normal conditions. Peptones have been 

 recovered from the blood, with certainty, in small amounts only. It is, 

 therefore, to be inferred that they are quickly retransformed into true 

 proteids. The mucous membrane possesses the property of retrans- 

 forming peptone into albumin. Heidenhain regards the epithelial cells 

 of the villi as the seat of this transformation. Peptone gains entrance 

 into the blood unchanged only in minimal amount and it disappears 

 from this after its passage through the tissues. 



If blood containing peptone is kept warm in the presence of a small piece of 

 small intestine, while air is passed through the mixture, the peptone soon disap- 

 pears from the blood. 



The peptones undoubtedly represent the principal contingent of the 

 albuminates destined for absorption. Of all the proteids they alone 

 suffice to maintain the body equilibrium, as animals fed upon peptone 

 only (in addition to the necessary fat or sugar) are able to maintain 

 their nutrition. They can do the same when fed with propeptone. 



According to Pfeiffer, the diffusion of the peptones is promoted by a i per 

 cent, solution of sodium chlorid or sulphate. The absorption of grape-sugar and 

 peptone in the stomach and intestine is increased by the addition of certain sub- 

 stances, as, for example, sodium chorid, pepper, alcohol or ethereal oils. In 

 dogs a peptone-solution (5 cu. cm. of a 20 per cent, solution in 0.6 per cent, sodium- 

 chlorid for an animal weighing 8 kilograms) introduced into the blood, causes 

 death. 



Unchanged Proteids. In spite of their slight power of filtration 

 and (on account of their great endosmotic equivalent) of diffusion, it 

 has been demonstrated with certainty that unchanged proteids, such 

 as liquid casein and the proteids of milk, meat-juice, dissolved myosin, 

 alkali- albuminate, egg- albumin mixed with sodium chlorid, syntonin, 

 gelatin, can be absorbed; their absorption takes place, in part, even 

 from the mucous membrane of the large intestine. The amount of 

 absorbed unaltered albumin is, however, smaller than that of the 

 peptones. 



Egg- albumin without sodium chlorid, serum-albumin, hemoglobin and fibrin 

 are not absorbed. Many years ago the author made the observation in a young 

 man that after the ingestion of the white of between 14 and 20 raw eggs, with 

 sodium chlorid, albumin was excreted in the urine after from 4 to 10 hours. The 

 amount of albumin thus excreted increased up to the third day, then becoming 

 less and ceasing on the fifth day. The more albumin ingested, the earlier the 

 albuminuria appeared and the longer it lasted. In this case the condition was 

 evidently one in which considerable absorption of unchanged egg-albumin took 

 place into the circulation. If egg-albumin be injected directly into the blood- 

 stream of animals, it likewise passes, in part, into the urine. 



The soluble soaps form only a part of the fats absorbed, the largest 

 portion of the fat being taken up in the form of a finely granular 

 emulsion. Absorbed soaps have, on the one hand, been found in the 

 chyle; on the other hand, from the circumstance that the blood of the 

 portal vein is richer in soaps at the time of absorption than during the 

 state of hunger, it has been inferred that absorption of the soaps takes 

 place, to some extent, through the intestinal capillaries. Nevertheless, 

 only a small portion of the soaps enters the blood. 



