CHOLESTEROL AND THE PHYTOSTEROLS 97 



CHOLESTEROL AND THE PHYTOSTEROLS. 



Cholesterol, C27H 45 OH, may be represented so far as our knowledge 

 at present extends, by the formula of von Fiirth: 



CH 3 



CH 3 



HOHC 



it is found in all animal fats or oils, in small quantities, in bile, blood, 

 milk, yolk of egg, the medullated sheaths of nerve-fibers, the liver, 

 kidneys and suprarenal bodies. It is contained in considerable amount 

 in cod-liver oil. Under pathological conditions it is found to constitute 

 a very large proportion of the most frequently occurring type of gall- 

 stones, the conditions which ordinarily hold cholesterol in solution in 

 bile, being in these cases, it appears, deficient. It occurs also in 

 atheromata of the arteries, in tubercular cysts and in carcinomatous 

 tissue. 



When precipitated from alcoholic solution by the addition of water, 

 or when deposited in the body, as in gall-stones, cholesterol forms 

 characteristic crystals with one re-entrant angle, resembling flat 

 rectangular plates with one corner knocked out (Fig. 2). These 

 crystals contain one molecule of water and are white, of a waxy con- 

 sistency, insoluble in water, soluble in alcohol, ether, benzol, etc., and 

 in fatty oils. When crystallized from anhydrous alcohol-ether mixtures 

 cholesterol forms acicular crystals without any water of crystallization. 

 Cholesterol may be held in solution or suspended in emulsified form in 

 water by the addition of soaps, saponins, bile-salts, or lecithin, and it is 

 by this means that it is held suspended in the bile and other tissue- 

 fluids. 



As has been stated above, there is reason to suppose that cholesterol 

 may possibly be decomposed in the suprarenal glands, and a portion is 

 possibly converted into cholic acid in the liver, but for the rest, so far 

 as we know at present, the main channel of excretion for cholesterol 

 is the bile. The cholesterol which thus finds its way into the upper 

 part of the small intestine, along with the cholesterol of the food, is in 

 part reabsorbed and in part retained in the intestine until it is voided 

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