FAT-ABSORBING FUNCTION OF ALIMENTARY TRACT OF KING SALMON. 1 55 



In 1890 Krehl ° made a restud\- oi the question of fat absorption from the intestinal 

 tract. His drawings showing different stages in the microscopic loading of the epithelial 

 cells with fat granules have become classic in the literature. The most significant fact 

 on which Krehl lays emphasis is "the fat is not taken up from the intestine in globular 

 form, but is absorbed in solution, and is resynthesized " giving rise to the droplets 

 observed in the pyloric epithelial cells which the author presents in his figures. The 

 conclusion that fat is absorbed in the dissolved state was later advocated by Pfliiger 

 (1900), after which it received general acceptance. 



In 1 901 Schilling '' again observed fat in the gastric epithelium of the calf, in this case 

 after a meal of milk. Schilling noted that the epithelial cells were thickly studded with 

 microscopic fat droplets and that fat deposits appeared in the connective tissue of the 

 tunica propria and parenchyma. He also noted fat in the lymphatic glands during 

 absorption. He apparently did not investigate the presence of fat in the lymphatic 

 radicles from the stomach. 



In 1908 Van Herwerden " published the results of extensive and valuable studies on 

 the gastric digestion in fishes. This subject he investigated under two heads, the second 

 of which, namely, "Enzymes in the gastric mucosa," concerns us here. Van Herwerden 

 made his observation chiefly on sharks, but also on bony fishes. These fishes he fed with 

 olive oil or egg-yolk emulsion, the food being introduced into the stomach by way of the 

 mouth. Having previously determined that fasting animals were relatively free of fat 

 granules, he states that upon killing animals after a certain number of hours following 

 feeding, "one finds fat drops in great numbers in the superficial epithelium." He states 

 further that "the fishes contained fat granules everywhere in the submucosa between 

 the musculature and especially in the lymph vessels which accompany the blood 

 vessels. In hungering fishes I have never found this to be the case." 



Van Herwerden also tested the activity of glycerin extracts of the gastric mucosa. 

 He found in Scyilium a decided increase in the formation of fatty acids; also, in teleosts, 

 his tables show the presence of an active lipolytic enzyme. Extracts previously boiled 

 gave always negative results, as did also extracts from the muscle walls of the alimentary 

 canal. 



These interesting observations of Van Herwerden seem to be the first that have been 

 made along this line upon the fishes. This splendid article had escaped my search in 

 the literature until after the publication of the preliminary report of the present work. 



Three previous communications have been made with reference to the present work; 

 the first relating briefly the observations on fat absorption from the pyloric coeca of 

 the king salmon,"* and the last two, one a prehminary* and the other a brief statement 

 of the facts of fat absorption from the stomach of the king salmon.-'' 



o Krehl, Ludolf: Ein Beitrag zur Fettresorption. Archiv fiir Anatomic und Physiologic (Anat. Abth.) 1890, p. 97. 



b Schilling. F.: Die Fettresorption im Magen. Fortschritteder>redicin, bd. 19. 1901, p. 613. 



c Van Herwerden. ^I.: Zur Magenvcrdauung der Fischc. Zeitschriftiiir Physiologische Chemie, bd. 56, 190S, p. 453-494. 



d Greene. Charles W.: The absorption of fats by the alimentary tract with special reference to the function of the pyloric coeca 

 in the king salmon. Oncorhynchus tschawylscha. Read before the St. Louis meeting of the American Fisheries Society. 1912. 

 Transactions American Fisheries Society, 1912, p. 261. 



f Greene, Charles W.; The absorption of fat by the salmon stomach. Preliminary notice. Proceedings American Physiolog- 

 ical Society, American Journal of Physiology', vol. 29. 1912, no. 4, p. xxxvi. 



/Greene, Charles W.: Absorption of fat by the salmon stomach. -American Journal of Physiology, vol. 30, p. 278. 1912. 



