CHOLESTERIN 367 



excess of ether. The taurocholate is precipitated in the form of dark 

 resinous drops which crystallize with difficulty. The glycocholate is 

 readily crystallizable. The biliary salts are very soluble in water and 

 in alcohol. Their reaction is neutral. 



There can be no doubt that the biliary salts are products of secre- 

 tion and are formed in the substance. of the liver. In no instance have 

 they been discovered in the blood in health ; and although they present 

 certain points of resemblance with some of the constituents of the urine, 

 they are not found in the excreta, except in very rare instances in the 

 urine. There is no reason, therefore, for supposing that these salts are 

 products of katabolism. Once discharged into the intestine, they undergo 

 certain changes and can no longer be recognized by the usual tests ; but 

 experiments have shown that, changed or unchanged, they are absorbed 

 with the products of digestion. They probably are concerned in the 

 digestive action of the bile. 



Cholesterin. Cholesterin (C 27 H 46 O) is a normal constituent of vari- 

 ous of the tissues and liquids of the body. Most authors state that it 

 is found in the bile, blood, liver, nervous tissue, crystalline lens, meco- 

 nium and fecal matter. It is to be found in all these situations, with 

 the exception of the feces, where it does not exist normally, being trans- 

 formed into stercorin in its passage down the intestinal canal. 



In the liquids of the body cholesterin exists in solution ; but by virtue 

 of what constituents it is held in this condition is a question not entirely 

 settled. It is stated that the biliary salts have the power of holding 

 cholesterin in solution in the bile, and that the small quantity of fatty 

 acids contained in the blood also holds it in solution ; but direct experi- 

 ments on this point are wanting. In the nervous tissue and in the crys- 

 talline lens, it is united with the other substances that go to make up 

 these parts. After it is discharged into the intestinal canal, when it is 

 not changed into stercorin it is to be found in a crystalline form, as in 

 the meconium and in the feces of certain animals in hibernation. In 

 pathological fluids and in tumors, it is found in a crystalline form and 

 may be detected by microscopical examination. 



Cholesterin is a monatomic alcohol. It is neutral, inodorous, crys- 

 tallizable, insoluble in water, soluble in ether, and very soluble in hot 

 alcohol though sparingly soluble in cold alcohol. It is inflammable and 

 burns with a bright flame. When treated with strong sulphuric acid 

 it strikes a peculiar red color. It may easily and certainly be recognized 

 under the microscope by the form of its crystals. These are rectangular 

 or rhomboidal, very thin and transparent, of variable size, with distinct 

 and usually regular borders, and frequently arranged in layers with 

 the borders of the lower strata showing through those which are super- 



