FATS LECITHIN CHOLESTEROL. 107 



gradually disappears. Large oil-drops are formed, which collect on the 

 surface of the liquid. It is very probable that the diminished fat absorp- 

 tion is largely dependent on the reduced alkalinity of the pancreatic juice, 

 on account of the acid contents of the stomach preventing the formation 

 of an emulsion in the duodenum. 



Although Teichmann l has shown that if the pancreatic duct of a dog 

 be ligated the absorption of fat is not appreciably affected, this does not 

 invalidate our assumption. The secretions in the small intestines of the 

 herbivora occur in greater alkalinity than is the case with the carnivora. 

 That milk-fat is even assimilated in the absence of pancreatic juice is 

 possibly explained by the following circumstances. If milk is coagulated 

 by means of rennet, and the coagulum then dissolved in pepsin-hydro- 

 chloric acid, we obtain a very stable, acid fat-emulsion. It is rather dif- 

 ficult to obtain a clear conception of the actual relations of fat assimilation, 

 so long as the conditions of fat digestion are so little understood. It is, 

 of course, possible that the stomach lipase continues to act in the duodenum 

 even when the alkaline pancreatic juice diminishes, and in this way a part 

 of the fat is decomposed. We are certainly not justified in concluding, 

 from the fact that fat assimilation proceeds in the absence of lipase, that 

 neutral fats are directly absorbed. 



The bile especially is of great importance in the absorption of fats. 

 Formerly, a direct influence on the intestinal epithelial cells was assigned 

 to it. It was supposed to stimulate them to assimilation. The function 

 of the bile, however, has been shown by Pfliiger 2 to consist of the ability 

 to produce solutions of the fatty acids and soaps. Large quantities of 

 stearic and palmitic acids were dissolved by a mixture of bile and sodium 

 carbonate. The cholates of the bile dissolve even the magnesium and 

 lime soaps which are insoluble in water. That the bile exerts a consider- 

 able influence on the absorption of fat is shown by the following observa- 

 tions : Dastre 3 ligated the bile duct of a dog, and made a fistula between 

 the gall bladder and the middle of the small intestine. With a diet rich 

 in fat the lacteals showed a milky turbidity below this fistula. The 

 bile acting alone does not seem capable of causing a fat assimilation, 

 although it acts more in conjunction with the pancreatic juice. This can 

 be shown very beautifully by an experiment upon a rabbit. In this 

 animal the bile duct joins the small intestine about ten centimeters above 

 the pancreatic duct. Between the junctions of these two passages the 

 chyle vessels remain clear and transparent, even on a diet rich in fat. 

 It is only below where the pancreatic juice enters that we notice the turbid 

 milky streams of fat-bearing chyle. 



1 Inaug. Diss. Breslau, 1891. 



3 E. Pfliiger: Pfliiger's Arch. 88, 299, 431 (1902); 90, 1 (1902). 



3 A. Dastre: Arch. phys. norm, et path. V. 22, 315 (1890). 



