102 CHOLESTEEINE. 



, 11. It is decomposed at 80 C; hence the analyses 

 must be made on a substance dried at 75, at which 

 temperature no decomposition occurs. 



Cholesterine, C 26 H M) 0. 1. Powder a human biliary 

 calculus, boil with alcohol and allow to cool ; the cho- 

 lesterine crystallises out in colourless laminae and 

 rhombic plates. 



2. Extract some brain substance with ether, boil the 

 ethereal extract with alcohol, allow to cool ; the cho- 

 lesterine crystallises out, but mixed with potassium 

 cerebrate and phosphate. Treat with ether and 

 evaporate ; the cholesterine will crystallise out. 



3. Cholesterine is white, tasteless, without smell ; it 

 is insoluble in water, it dissolves with difficulty in cold 

 but easily in boiling alcohol. 



4. Mix some cholesterine with a little dilute sulphuric 

 acid, warm gently, add gradually some concentrated 

 sulphuric acid : the cholesterine will soften and acquire 

 a deep red colour without evolving any gas. 



5. Heat some cholesterine cautiously in an inclined 

 glass tube ; it will fuse, boil and distil, and be con- 

 densed as a solid crystalline mass in the cold part of 

 the tube. 



6. Enclose cholesterine with any free fatty acid in a 

 glass tube, seal by fusion and heat the tube for a long 

 time to 150. The cholesterine will combine with the 

 fatty acid and form a cholesteride or body similar to 

 the glycerides or ordinary fats. 



Cholic acid, C^H^Og, 1. Boil glykocholic or tauro- 

 cholic acid, or purified bile, with excess of hot con- 



