CHOLESTERINE. 



75 



proves nothing, since most of the tissues of the animals on which 

 they prey also contain it. 



It is also very certain that the human liver has the power to form] 

 fat directly, to some extent, as well as sugar (p. 71). It is not, 

 however, probable that the adipose tissue is nourished by fat formed 

 elsewhere in the organism, but that the fatty materials for its nutri- 

 tion are contained in the food, or, in default thereof, may be ^labp- 

 rated by the fat-cells themselves out of the other elements brought 

 to them in the blood. But that almost all the fatty principles in the 

 body are, under all ordinary circumstances, introduced in the food, 

 hardly admits of a reasonable doubt. 



Of the fatty principles which enter the blood, a portion is appro- 

 priated to the nutrition of the adipose tissue, and others normally 

 inclosing "fat-globules," and for the secretions which contain the 

 latter ; the remainder is burned up by combination with oxygen to 

 maintain the animal heat, and leaves the body in the form of car- 

 bonic acid and water. 



Though the fatty principles possess great physiological' import- 

 ance, only oleine, margarine, and stearine are especially important 

 to the histologist. These, therefore, and cholesterine, will alone be 

 here considered. "Seroline" has been shown by Lehmann to con- 

 sist of the crystallizable parts of several fats blended together. 



1. Cholesterine. (C 37 H 32 0.) 



Cholesterine (or bile-fat) crystallizes in very thin rhombic tablets. 

 (Fig. 41.) It is normally dissolved in the bile, and is found in the 

 blood, bile, liver, brain, nerves, 

 feces, cerumen, the crystalline 

 lens, and in many pathological 

 productions. Gall-stones are 

 composed almost entirely of it. 



The blood contains about .088 

 parts of cholesterine in 1,000. 

 It increases in old age, and in 

 most acute diseases; especially 

 in inflammations, and in icterus. 

 It also occurs in pus, and often 

 in dropsical transudations, creta- 

 ceous tubercles, old echinococ- 



CUS CyStS, encysted tumors, de- Tablets of oholesterine. 



Fig. 41. 



