FATS. 8.3 



gently distilling the ethereal solution, a residue remains, from 

 which cholesterin may be taken up by boiling alcohol ; on 

 mixing the two alcoholic solutions, evaporating to one fourth, 

 and allowing the mixtm-e to cool, a portion of the fat separates 

 in the form of a white powder, which consists not merely of 

 cholesterin, but also of a substance which is insoluble in cold 

 ether, the cerebrot of Couerbe. If, therefore, we treat this fat 

 with ether, the cholesterin dissolves, while the cerebrot remains 

 unacted on. By evaporation we obtain the cholesterin in a 

 crystalline state, and by dissolving it in boiling alcohol and 

 allowing it to recrystallize on cooling, we obtain it in a state 

 of purity. 



On slowly cooling its alcoholic solution, cholesterin crystal- 

 lizes in dehcate white nacreous scales. It is devoid of taste 

 and smell, is insoluble in water, but dissolves in alcohol and 

 in ether. According to Chevreul, 100 parts of boiling alcohol 

 of 0-816 dissolve 18 of cholesterin ; if alcohol of 0-840 be used 

 only 11*24 parts are taken up : on cooling, the greater part is 

 deposited. Ktihn states that 1 part of cholesterin is soluble 

 in 12-1 of ether at 32°, in 3-7 parts at 59°, and in 2*2 parts of 

 boiling ether. Cholesterin is perfectly neutral, of about the 

 same specific gravity as water, and at 280° melts into a colour- 

 less fluid without undergoing any decomposition. Crystallized 

 cholesterin contains about 5-2^ of water. It burns with a clear 

 flame, like wax, and one of its most striking characteristics is, 

 that it is not affected by a solution of caustic potash. 



Its composition is represented by the formula C^. H^^ O. 



b. Sei'olin. This name was given by Boudet to a fatty 

 matter which he discovered in the blood. It has been more 

 recentlj^ found and described by Lecanu and Sanson. In order 

 to exhiljit it, blood must be first evaporated to dryness on 

 the Avater-bath, and the residue treated with water as long 

 as anything continues to be taken up. It must then be dried, 

 pulverized, treated with boiling alcohol, and filtered while hot. 

 On cooling, the alcohol deposits this fat in flocculi. It must 

 be collected on a filter, and washed with cold alcohol. Boudet 

 assigns the following characteristics to serolin. It forms flocks 

 of a fatty nacreous appearance, is perfectly neutral, and melts 

 at 97°. On exposing it to a higher temperature, a portion 

 is distilled unchanged, while another part is decomposed into 



