300 ABSORPTION OF FATTY PARTICLES. 



siura cyanide has been found in the chyle. [If salts (KI, sulphocyanide of ammonium) be 

 injected into a ligatured loop of intestine (dog, cat, rabbit), these substances are absorbed both 

 by the blood- and lymph -vessels, and in both nearly simultaneously.] Even for the absorption 

 of completely fluid substances, endosmosis and filtration seem to be scarcely sufficient. An 

 active participation of the protoplasm of the cells seems here also in part at least to be 

 necessary, else it is difficult to explain how very slight disturbances in the activity of these 

 cells, e.g., from intestinal catarrh, cause sudden variations of absorption, and even the passage 

 of fluids into the intestine. 



If absorption were due to diffusion alone, when alcohol is injected into the intestine, water 

 ought to pass into the intestine, but this does not occur. Brieger found that the injection of a 

 "5 to 1 per cent, solution of salts into a ligatured loop of intestine did not cause water to pass 

 into the intestine ; but it appeared when a 20 per cent, solution was injected. 



II. Absorption of the Smallest Particles. The largest amount of the fats is 

 absorbed in the form of a milk-like emulsion, formed by the action of the bile and 

 the pancreatic juice, and consisting of excessively small granules of uniform 'size 

 ( 170, III.; 181). The fats themselves are not chemically changed, but remain 

 as undecomposed neutral fats. The particles seem to be surrounded by a delicate 

 albuminous envelope, or haptogen membrane, partly derived from the pancreatic 

 juice [probably from its alkali-albuminate]. The villi of the small intestine are 

 the chief organs concerned in the absorption of the fatty emulsion, but the epithe- 

 lium of the stomach and that of the large intestine also take a part. The fatty 

 granules are recognised in the villi (1) Within the delicate canals 1 ( 190) in the 

 clear band of the epithelium (Kolliker). [It is highly doubtful if the vertical lines 

 seen in the clear disc of the epithelium of the intestine are due to pores.] (2) The 

 protoplasm of the epithelial cells is loaded with fatty granules of various sizes 

 during the time of absorption, while the nuclei of the cells remain free, although, 

 from the amount of fat within the cells, it is often difficult to distinguish them. 

 (3) The granules pass into the spaces of the parenchyma of the villi; these spaces 

 communicate freely with each other. (4) The origin of the lacteal in the axis of 

 the villus is found to be filled with fatty granules. The amount of fat in the chyle 

 of a dog, after a fatty meal, is 8 to 10 per cent., while the fat disappears from the 

 blood within thirty hours. 



With regard to the forces concerned in the absorption of fats, v. Wisting- 

 hausen proved, that when a porous membrane is moistened with bile, the passage 

 of fatty particles through it is thereby facilitated, but this fact alone does not ex- 

 plain the copious and rapid absorption of fats. It is possible that the protoplasm 

 of the epithelial cells is actively concerned in the process, and that it takes the 

 particles into its interior. Perhaps a fine protoplasmic process is thrown out by 

 these cells, just as pseudopodia are thrown out and retracted by lower organisms. 

 It is possible that absorption may take place through the open mouths of the 

 goblet-cells. The protoplasm of the epithelial cells is in direct communication with 

 the numerous protoplasmic lymph-cells within the reticulum of the villi, so that the 

 particles may pass into these, and from them through the stomata (?) between the 

 endothelial cells into the central lacteal of the villus. According to this view, the 

 absorption of fatty particles, and perhaps also the absorption of true proteids, is 

 due to an active vital process, as indicated by the observations of Briicke and v. 

 ThanhofFer. This view is supported by the observation of Griinhagen, that the 

 absorption of fatty particles in the frog is most active at the temperature at which 

 the motor phenomena of protoplasm are most lively. That it is due to simple 

 filtration alone is not a satisfactory explanation, for the amount of fatty particles- 

 in the chyle is independent of the amount of water in it. If absorption were chiefly 

 due to filtration, we would expect that there would most probably be a direct re- 

 lation between the amount of water and fat (Lvdwig and Zawilsky). [The 

 observations of Watney have led him to suppose that the fatty particles do not 

 pass through the cell protoplasm to reach the lacteal, but that they pass through 

 the cement-substance between the epithelial cells covering a villus. If this view be 





