470 Origin and Destiny of Cholesterol in the Animal Organism. 



solution was evaporated and the solid recrystallised from 95-per-cent. 

 alcohol. The crystalline matter which separated was impure, and, even after 

 recrystallisation, we could recognise under the microscope no crystals which 

 could be definitely described as cholesterol. The whole was then converted 

 into benzoate by the action of benzoyl chloride in pyridin solution ; 

 - 068 grm. of a benzoate was obtained, which, after repeated recrystallisation 

 from alcohol, was still slightly yellow in colour. It melted at 142° C. to 

 a clear brown liquid, which, on cooling, gave a brilliant green play of colours 

 at the moment of solidification, gradually changing to brown. This behaviour 

 was quite different from cholesterol benzoate, which melts at 145° to a turbid 

 liquid, only becoming clear at about 180°, and, on cooling, gives a play of 

 purple and blue colours of quite characteristic appearance. Under the 

 microscope the crystalline matter was indefinite in appearance and one 

 could find none of the characteristic square envelopes of cholesterol benzoate. 



Had the - 97 grm. of insoluble digitonin compound consisted entirely of 

 cholesterol digitonide, it would have corresponded to 024 grm. of cholesterol, 

 an output of only O016 grm. per day. 



In order to determine satisfactorily the nature of the unsaponifiable 

 residue, it will be necessary to prepare it in large quantity, and this we 

 must reserve for a further investigation. 



We take this opportunity of thanking the Government Grant Committee 

 ■of the Koyal Society for help in carrying out this work. 



