204 VETERINARY PAIIIOLOGY. 



strated, however, b)- Prof. Hopkins, of the University of Illi- 

 nois, that the bod)- fat is the same as the ingested fat. (Hogs 

 were fed on cotton seed oil and the presence of the same kind 

 of fat was demonstrated in the Img tissue.) It has also been 

 found that butter fat in cow's milk is the same as ingested fat. 

 Opinions are at variance in reference to the digestion and assim- 

 ilation (if fat. The fat splitting enzyms convert the fats into 

 fattv acids and glycerine. The alkali present in the intestines 

 unites w ith a part of the fatty acid, forming soap, the latter and 

 the glycerine pass by osmosis into the intestinal epithelium or 

 through the mucous membrane where the glycerine is substituted 

 for the alkali, the alkali passing back into the intestinal lumen 

 to form more soap (llamniersten). Some of the fat may be so 

 finelv emulsified that it passes directly into and through the in- 

 testinal epithelium, and some of it may be incorporated by leu- 

 cocytes, and thus carried from the lumen of the intestine to the 

 lacteals (Howell), h'at droplets are present in the circulating 

 blood. The e.xact manner of the production of fat cells in normal 

 adipose tissue has not been determined. 



All normal animal tissues contain varying quantities of neu- 

 tral fat. As much as 33 per cent of fat has been extracted from 

 kidnev tissue (Adanii). The pro])ortion of neutral fat in the 

 same kind of tissue varies in the same animal under different 

 conditi(jns and in animals of different species under the same 

 conditions, lluis the quantity of fat in the muscular tissue of 

 an emaciated animal is less than in an animal in good flesh. The 

 muscular tissue of the hog contains more fat than the muscular 

 tissue of the ox, sheep, horse or dog. In fact the presence of fat 

 droplets betwen the nuiscle cells is a distinguishing characteris- 

 tic of porcine muscular tissue. There is no definite limit to the 

 quantitv of fat normallv contained in the tissues of any animal. 



Certain abnormal fattv changes occurring in the various tis- 

 sues have l)een described as fatty infiltration and fatty degen- 

 eration. These changes, although originally thought to be en- 

 tirely distinct, are closely related and may represent different 

 Stages of the same process. These fattv changes may be dis- 

 cussed as physiologic fatty changes (fattv infiltration), and path- 

 ologic fatty changes (fatty degeneration), although there is no 

 good reason for the division of the subject other than to recog- 

 nize the previous classification and prevent undue confusion. 



