DIGESTION OF THE FATS. / 181 



the steapsin of the pancreatic juice. This, as we have seen, brings 

 about a partial decomposition of the neutral fat, and it is thought 

 that the resulting fatty acids combine with the alkalies of the pan- 

 creatic juice and the bile to form soaps, and that these in turn 

 emulsify the neutral fats. ^We might hence conclude that the pres- 

 ence of the alkali in these secretions is the essential factor which 

 renders the absorption of the fats possible. I have shown that the 

 succus entericus is manifestly incapable of furnishing this in suffi- 

 cient amount, as large quantities of the fatty acids appear in the 

 feces as such when either the bile or the pancreatic juice is pre- 

 vented from entering the intestinal canal. It has been found, on 

 the other hand, that even in the absence of the pancreas the absorp- 

 tion of fats may be fairly normal providing that fresh pancreas, 

 finely hashed, is given the animal together with the fatty food. 

 Kuhne, moreover, has demonstrated that pancreatic juice, even after 

 having been rendered feebly acid, is still capable of emulsifying 

 fats. He also pointed out long ago that while the secretion from 

 permanent pancreatic fistula? can bring about the emulsification 

 of fats, the juice obtained from temporary fistula? is much more 

 potent in this respect. He accordingly concluded that this property 

 is essentially referable to albumins which are present in solution, 

 and he showed, moreover, that these are capable of bringing about 

 the emulsification of fats even in feebly acid solution. This opin- 

 ion is shared by Minkowski and others, and the fact that the fat of 

 milk can be resorbed much more readily than other fats is now 

 generally explaineoT upon this basis. However this may be, the 

 fact remains that resorption of fats can only proceed in a normal 

 manner if emulsification has previously taken place. y 



At present there is a tendency among physiologists to assume that ^ 

 the digestion of the fats presupposes their decomposition into fatty 

 acids and glycerin. The former, in the form of soaps, are then 

 supposedly absorbed and reconstructed into neutral fats in the epi- 

 thelial cells, which possibly obtain the requisite amount of glycerin 

 from the intestinal lymph-glands. It must be admitted that this 

 view has much in its favor, but it cannot as yet be regarded as an 

 established fact. 



Of the manner in which resorption occurs, we now know that, 

 contrary to the former supposition, according to which the leucocytes 

 play an active part in this process, the epithelial cells are of prime 

 importance, and it seems that even though the neutral flits may be 

 absorbed directly, a synthesis of fats from fatty acids or their soaps- 

 can here also take place. This indeed is the prevailing idea at the 

 present time, and, as I have said, the glycerin which is necessary 

 to effect this synthesis is in all probability derived from the lymph- 

 glands of the intestinal tract, but it is also possible that it may be 

 formed in the cells themselves or may be absorbed together with 

 the soaps. 



It is stated that the bile assists in the resorption of flit from the 



