v INTEKNAL KESTITUTIVE SECKETIONS 287 



be absorbed in 1-4 hours, without showing the least trace of 

 proteose or peptone previous to their disappearance. 



In a subsequent study of the absorption of different alimentary 

 substances introduced per rectum into the large intestine (a method 

 that found wide application in clinical medicine) Eichhorst (1871) 

 found that in addition to myosin and syntouin the protein of 

 milk and metaprotein were capable of absorption, without any 

 trace of peptonisatiou, in the large intestine. 



The same fact was observed by Czerny and Latschemberger in 

 man, in a case of fistula of the sigmoid flexure, which allowed 

 perfect washing out and disinfection of the rectum, so as to 

 exclude all intervention of proteolytic enzymes and bacteria. 

 Nencki and his pupils (1891) arrived at the same results, experi- 

 menting on man in a similar case of fistula of the large bowel. 

 Their results show that 70 per cent of dissolved metaprotein can 

 be absorbed in a day. 



These same proteins, injected directly into the veins, are 

 eliminated in the urine in the form of urea only. They are there- 

 fore utilised by the body, and require no digestive alteration to 

 fit them for assimilation. It is otherwise with ovalbumin, 

 caseinogen, haemoglobin, and gluten, which substances, if injected 

 into the blood, are eliminated unchanged in the urine. 



Ovalbumin must therefore be transformed into syntonin 

 by the action of the gastric juice, before it can be utilised. In 

 fact, when introduced per rectum in the natural state it is not 

 absorbed (Bauer); ingested by the mouth in large quantities it 

 can be absorbed, but produces albuminuria (Briicke). Directly 

 sodium chloride is added, however, it becomes absorbable, though 

 very slowly, and can be utilised (Voit, Bauer, Eichhorst, Huber). 



It has not yet been discovered why the addition of sodium 

 chloride renders the mucous membrane of both large and small 

 intestine permeable to egg-albumin, which in itself is inabsorbable. 

 All explanation of the fact is wanting, but it has been positively 

 confirmed and established. Baldi (1896), in a series of very clear 

 and simple comparative experiments, showed that solutions of 

 commercial peptone (which consists principally of proteoses) are 

 also absorbed more rapidly from a Vella's loop, if a little sodium 

 chloride be added. 



Caseinogen is normally refractory to absorption owing to the 

 coagulation it undergoes in the stomach from the enzymatic 

 action of the chymosin of the gastric juice ; hence it can only be 

 absorbed after decomposition into syntonin and nuclein. Haemo- 

 globin, too, is broken up by the action of the gastric acid into 

 albumin and haematin : the first can be absorbed as such, the 

 second is eliminated for the most part with the faeces, and is only 

 to a minor extent utilised by the liver in the formation of bile- 

 pigments. 



