SEROL1N. 155 



According to this statement, the atomic weight of cholesterin is 

 33*5. We have seen that the crystals are composed of, 

 Cholesterin, 94-85 or 67 

 Water, 5-15 or 3.636 



100-00 



Now 3-636 is very nearly the weight of 3 atoms of water- 

 Hence it is not unlikely that the true atomic weight of choles- 

 terin is 67, and that its constitution is C 76 H 64 O 2 = 67. 



M. Couerbe found cholesterin in the human brain* and doubt- 

 less it may be extracted from the brains of most of the Mamma- 

 lia. The brain was digested four times successively in ether, 

 till every thing soluble in that liquid was taken up. The resi- 

 due was treated with boiling alcohol till every thing soluble in 

 that liquid was abstracted. The alcohol on cooling deposited a 

 white matter. This white matter being digested in cold ether 

 a quantity of cholesterin is dissolved, which separates in crystals 

 when the ether is evaporated. 



The quantity of cholesterin in the brain is considerable. It 

 possesses the same characters as that from biliary calculi, except- 

 ing that it does not melt till heated to 293. It remains in a 

 liquid state till cooled down to 239, provided it be quite still, 

 but the least agitation, that for instance caused by touching it 

 with a hair, makes it immediately congeal into a crystalline so- 

 lid. Couerbe found the ultimate constituents of cholesterin from 

 biliary calculi, and from the brain the same. The cholesterin 

 from the brain differs from that of biliary calculi in one remark- 

 able circumstance. It dissolves better in alcohol, and furnishes 

 a solution as it were unctuous. When filtered and allowed to 

 cool it does not deposite crystals immediately. The crystalli- 

 zation begins after an interval of some time. The crystals are 

 plates, often several inches long and beautiful, provided no cere- 

 brote be present. 



SECTION VII. OF SEROLIN. 



This substance was detected in the serum of blood by M. 

 Boudet in 1833.f He obtained it by setting aside a hot alco- 

 holic decoction of dried serum. As the alcohol cooled, a white mat- 

 ter, having a slightly pearly lustre, was deposited. It was sero- 

 lin. 



* Ann. de Chim. et de Phys. Ivi. 180. f Jour, de Pharm. xix. 29& 



