154 BULLETIN OF THE BUREAU OF FISHERIES. 



This point of view has been arrived at through certain classic researches which will 

 DC reviewed briefly and which for the present purpose may begin with the work of 

 E. H. Weber. 



In 1847 Weber" demonstrated that during fat absorption the superficial epithelium 

 of the duodenal villi was filled with fat granules. He says that the cylindrical epithe- 

 lial cells "swell up and contain chyle granules" and that "the cylindrical cells are no 

 longer cylindrical or prismatic, but are round, and many become whitish-opaque 

 while others are filled with transparent oily fluid." This he explains as due to the 

 power of the cells to absorb the food materials. Weber showed that some of the paren- 

 chymal cells also became opaque, containing oil-like fluids. This seems to have been 

 the first microscopic observation of the absorption of fats by the intestinal epithelium. 



Kolliker * in 1857 made similar observations, showing that fat was absorbed in the 

 stomach. He also used the histological method. Kolliker found highly refractive fat 

 granules in the fresh tissue. On page 175 is the statement, "I have never failed to 

 find fat in the stomach epithelium in the dog, cat, or mouse from the second day after 

 birth on. The mass of fat was indeed very variable. The cells may contain only slight 

 masses of fine granules or they may be gorged with fat in which not only the finer but 

 also larger fat drops are present." It is significant that he found the fat only in the 

 cylindrical cells, i. e., not in the pavement epithelium of the mouse's stomach. This 

 definite work of Kolliker on the ability of the gastric mucosa to absorb fat has appar- 

 ently been overlooked by physiologists until the last few years. 



The question of the method by which fat is absorbed has been inseparably associated 

 with the observations of the actual physical processes of absorption. Our current view, 

 that fat must be dissociated before absorption, received its first experimental support, 

 so far as the stomach is concerned, by the work of Marcet " in 1858. This author 

 delivered a course of lectures in London, discussing in the last of the series the evidence 

 of the digestion of fat in the stomach. The keynote to his work is explained in the 

 following quotation: "The experiments were undertaken upon dogs, and repeated four 

 times with the same result. The animals were made to take a meal, consisting of cooked 

 meat and sheep's fat, and were killed from one to five hours later; the contents of the 

 stomach being at once submitted to examination yielded in every case fatty acids." 



This chemical work of Marcet gave an admirable support to the histological observa- 

 tions of Kolliker, showing that the gastric mucosa is capable of producing fat-splitting 

 ferments, or as we now call them, lipolytic enzymes. In the light of our present 

 knowledge, these two pieces of work, that of Kolliker and of Marcet, should have estab- 

 lished the fact of the fat digestion and absorption in the stomach. But no further 

 reference along this line seems to be available from the literature until the work of Cash <^ 

 in 1880, who, without reference to the previous work of Marcet, again investigated the 

 fat-splitting properties of the gastric juice and of the extracts of the gastric mucosa. 



« Weber, E. H.: Ueber den Mechanismus der Einsau^ung des Speisesaftes beim Menschen and bei einigen Thieren. MiiUer, 

 Archiv fiir Anatomic und Physiologie. bd. 6, 1847, p. 400-402. 



b Kolliker, A. von: Eiuige Bemerkungcn ueber die Resorption des Fettes im Darmc, ueber das Vorkommen einer physio- 

 logischen Fettleber bei jungen Saugethieren und ueber die Function der Milz. Verhandlungen der pbysikalisch-Medicinischen 

 Gesellsch. Bd. 7. 1857, p. 174-193. 



^Marcet: A course of lectures on the chemistry, physiology, and pathology of human excrements. Lecturev. TheMedical 

 Times and Gazette, vol. 17. 1858, p. 209. 



•^Cash. Th.: Ueber den Antheil des Magens und Pankreae an der Verdauung des Fettes. Archiv fiir Anatomie und Phy- 

 siologie (Phys. Abth.) 1.S.S0, p. 323-333. 



