540 DIGESTION. 



of the digestion, such as upon the formation of the secretions and their 

 activity. As to this we know at present very little, but the work of 

 ZUNZ and MAYER (see page 532), indicates that such a reverse action is 

 possible. Under these circumstances it is not possible to give LOMBROSO'S 

 views too great a prominence. 



LOMBROSO has also found that after the extirpation of the pancreas 

 in the dog, sometimes more fat is eliminated than was contained in the 

 food; that this eliminated fat, which^ depends upon a fat secretion into 

 the intestinal canal, has a different composition from the introduced fat, 

 and that in these cases an absorption of fat also takes place. That some 

 fat can be absorbed in animals even in the absence of the bile as well 

 as pancreatic juice has been shown by the investigations of HEDON and 



VlLLE and CUNNINGHAM. 1 



The reason for the fact that the fat absorption is diminished in the 

 absence of bile from the intestine must be sought for in the above-men- 

 tioned r61e of this fluid. It is more difficult to state why the absence 

 of pancreatic juice causes a reduction in the absorption of fat. The most 

 natural view is that the neutral fats are here less completely split, but 

 this does not seem to be the case, because the non-absorbed fat of the 

 feces consists, on the exclusion of bile and pancreatic juice (MINKOWSKI 

 and ABELMANN, HARLEY, HEDON and VILLE, DEUCHER), principally of 

 free fatty acids. A still unknown change caused by gastric or intestinal 

 lipase or by micro-organisms may produce a cleavage of the fat in these 

 cases. The imperfect fat absorption after the extirpation of the pan- 

 creas can possibly be explained by the removal of a considerable part 

 of the alkalies necessary for the formation of the emulsion and for the 

 solution of the fatty acids, but as SANDMEYER found in dogs deprived of 

 their pancreas, that the fat absorption was raised by giving chopped 

 pancreas with the fat, this can hardly be a sufficient explanation. The 

 reason for this is perhaps that after the extirpation of the pancreas the 

 splitting of the fat is chiefly brought about by bacteria in those parts of 

 the intestinal canal where the conditions for absorption are not favor- 

 able. 



The soluble salts are also absorbed with the water. The proteins, 

 which can dissolve a considerable quantity of salts, such as earthy phos- 

 phates which are otherwise insoluble in alkaline water, are of great 

 importance in the absorption of such salts. 



The soluble constituents of the digestive secretions can be absorbed 

 like the other soluble substances and toxines, and ferments may also be 

 absorbed, especially by a diseased change in the intestinal walls. 



The occurrence of urobilin in urine attests the absorption of the bile- 



1 H6don and Ville, 1. c.; Cunningham, Journ. of Physiol., 32. 



