l64 BULLETIN OF THE BUREAU OF FISHERIES. 



Fat in the .stomach. — Sections of the gastric division of the stomach showed the outer ends of 

 the epithelial cells medium full of fine fat droplets, shou-n in figure i. These droplets are in the 

 extreme outer ends of the cells just within the striated border. They are strikingly smaller than the 

 droplets present in the intestinal and coecal epithelium of the same specimen. A sprinkling of fat 

 droplets is present in the inner limbs of the gastric epithelial cells. 



McCloud River Salmon, Field Series No. 88, Female, Length 84 Millimeters, Taken Ji;ly 23, 



igii. 



This young salmon was seined from the McCloud River and was i year old as verified by scales. 

 It was fed fat by the method of rectal injection and killed after :!o hours. 



Fat in the pyloric caeca. — Frozen sections were made of the pyloric cceca and these stained with 

 scarlet red and counterstained with haeraatoxylin. Absorption fat was present in moderate quantity, 

 see figure 9. The greater portion of the fat is limited to the outer ends of the cells, but a few droplets 

 were present in the inner ends of the cells and a small amount in the tunica propria. 



Fal in the stomach. — This specimen showed an unusual amount of absorption in the gastric epithe- 

 lium. Particularly was the pyloric epithelium loaded with fat. (See fig. i.) Many of the deep 

 folds of the pyloric epithelium were practically free of fat, but those cells dipping deepest into the 

 cavity of the stomach were unexpectedly filled. 



Two sections of cardiac stomach were fat-stained only. The slender cylindrical epithelial cells of 

 the mucous ridges bordering on the lumen of the stomach and those cells extending down into the crypts 

 of this somewhat contracted stomach all show numbers of droplets. The fat is greatest in amount in 

 the cells of the free folds. The fat is finely divided in appearance, that is, in minute droplets. It is 

 greatest in quantity in the outer thirds of the cells. There is a transparent superficial border of the 

 epithelial coat in which the fat is in the form of finest liposomes, requiring the oil immersion lens for 

 resolution. (See fig. i of osmic acid staining of no. 46, Greene, American Journal of Physiology, 

 vol. 30, p. 280.) There is also fat in the inner limbs of the cells down to their bases, and this is more 

 or less continuous with small amounts of fat in the tunica propria. 



The gland cells of the secreting portion of the stomach in this section are granular in appearance 

 and slightly pink with scarlet red. In several regions very small fat droplets, the size of which varies 

 around 0.5 /i, are found in the basal portion of many of the gland cells. In connection with the large 

 majority of the gland tubes in this slide there are cell areas over the surface of the tubes which seem 

 quite thickly studded with finest fat droplets. This section is not counterstained, so it is difficult 

 to determine to exactly what tissue these cells belong. In some instances they undoubtedly belong 

 to the connective tissue of the tunica propria surrounding the gland tubes. 



Several of the submucous areas just within the circular muscle and through which blood vessels 

 run are finely punctate (oil immersion lens) with liposomes. Vascular areas in the longitudinal muscle 

 coat are also stippled with liposomes, the droplets being located in the endothelial cells and in the 

 walls of the blood vessels. 



McCloud River Salmon, Field Series No. qi, Male. Length 83 Millimeters, Taken July 25. 191 1. 



A young salmon seined from the McCloud River, fed olive oil by the method of rectal injection 

 and killed after 70 hours. 



Fat in the pyloric caeca. — Transverse sections of the pyloric coeca were made by the freezing method 

 and stained for fat. Figure 10 shows a characteristic section from this fish. The amount of fat in the 

 outer portion of the epithelial tissue is unusually great, though a very small amount had penetrated 

 the inner limbs of the epithelial cells, and practically none to the tunica propria. The length of time 

 that had been allowed for absorption would justify the expectation that the tunica propria would be 

 loaded as shown in figure 8, from no. 46. Such was not the case. Possibly fat was late in entering 

 the particular group of coeca examined. 



The amount of fat in this material, as in the cceca of all of the fat-fed salmon, is unquestionably 

 from fat absorption. The control materials, salmon no. 82 to 86, presented no fat in the epithelium of 

 the coeca and only traces in the tunica propria. 



