ABSORPTION OF BILE. 541 



constituents under physiological conditions despite the fact that the 

 occurrence of very small traces of bile-acids in the urine is disputed. 

 The absorption of bile-acids by the intestine seems to be positively proved 

 by other observations. TAPPEINER 1 introduced a solution of bile- 

 salts of a known concentration into an intestinal knot and after a time 

 investigated the contents. He found that in the jejunum and the ileum, 

 but not in the duodenum, an absorption of bile-acids took place, and 

 further that of the two bile-acids only the glycocholic acid was absorbed 

 in the jejunum. Further, SCHIFF long ago expressed the opinion that 

 bile undergoes an intermediate circulation, in such wise that it is 

 absorbed from the intestine, then carried to the liver by the blood, and 

 lastly eliminated from the blood by this organ. Although this view has 

 met with some opposition, still its correctness seems to be established by 

 the researches of various investigators, and more recently by PREVOST and 

 BINET, and specially by STADELMANN and his pupils. 2 After the intro- 

 duction of foreign bile into the intestine of an animal, the foreign bile- 

 acids appear again in the secreted bile. 



How does the removal of large portions of the various parts of the 

 intestine affect absorption? HARLEY S has been able to perform a par- 

 tial extirpation of the large intestine and in another instance a com- 

 plete extirpation. This last condition increased the feces considerably, 

 especially because of the large increase in the water (five-fold). Fats 

 and carbohydrates were absorbed just as completely as in the normal. 

 The absorption of the proteins, on the contrary, was reduced to only 

 84 per cent as compared to 93-98 per cent in normal dogs. After extir- 

 pation, the feces sometimes did not contain any urobilin, or only traces 

 thereof, while bile-pigments existed in large amounts. 



ERLANGER and HEWLETT found that dogs from which 70-83 per 

 cent of the total length of the jejunum and ileum had been removed, 

 could be kept alive, like other animals, if only the food was not too rich 

 in fat. When the food contained large amounts of fat then 25 per 

 cent was evacuated by the feces as compared to 4-5 per cent in the 

 normal animal. Under these same conditions the amount of nitrogen 

 in the feces was increased to twice the normal amount. LONDON and 

 STASSOW* found on resection of the ileum that the eliminated diges- 

 tion and absorption were performed by the parts of the intestine higher 



1 Wien. Sitzungsber., 77. 



2 Schiff, Pfliiger's Arch., 3; Prevost and Binet, Compt. Rend., 106; Stadelmann, 

 see footnote 1, p. 416. 



3 Proceed. Roy. Soc., 64. 



4 Erlanger and Hewlett, Amer. Journ. of Physiol. 6; London and Stassow. Zeitschr. 

 f.physiol. Chem. 74, 349 (1911). 



