129 



The Origin and Destiny of Cholesterol in the Animal Organism. 

 Part IV. — The Cholesterol Contents of Eggs and Chicks. 



By G. W. Ellis and J. A. Gardner, Lecturer on Physiological Chemistry, 



University of London. 



(Communicated by Dr. A. D. Waller, F.R.S. Received January 15, — - 

 Read February 11, 1909.) 



(From the Physiological Laboratory, South Kensington, University of London.) 



In a paper recently communicated to the Royal Society* the hypothesis 

 was advanced that cholesterol is a substance which is strictly conserved 

 in the animal organism. As it is difficult to conceive how a body of 

 the constitution of cholesterol can be synthesised in the organism from 

 proteids, carbohydrate or fat, it was suggested that the waste of cholesterol 

 might be made up from the food taken by the animal. In order to test the 

 correctness of this view we thought that evidence of fundamental importanc 

 might be obtained by comparing the cholesterol content of eggs and newly- 

 hatched chicks, and also by ascertaining whether chicks could be reared and 

 would thrive on food deprived of its cholesterol or phytosterol. In this 

 paper we give an account of our estimations of cholesterol in hens' eggs and 

 newly-hatched chicks. 



Method of Estimation. — The weighed egg or chick (including broken shell) 

 was pounded up in a mortar with sand and sufficient plaster of Paris to 

 cause the whole to set after a time to a dry mass. This was powdered and 

 extracted in a Soxhlet's apparatus with ether for about twelve days. The 

 ethereal solution of the extract was saponified in the cold by means of an 

 alcoholic solution of sodium ethylate. After standing overnight the 

 precipitated soap was filtered off and thoroughly washed with ether. The 

 filtrate and washings were repeatedly shaken with water to get rid of 

 alcohol, excess of alkali, traces of soap, etc., dried with calcium chloride and 

 the ether distilled off. The residue was dried at 100° C. and weighed. In 

 the case in which single eggs or chicks were analysed, the dry residue, 

 dissolved in 10 c.c. of pyridine, was mixed with about three times its weight 

 of benzoyl chloride also in solution in 10 c.c. of pyridine. After standing 

 overnight the liquid was poured into water, and the precipitated cholesterol 

 benzoate after drying was boiled with 10 c.c. of absolute alcohol and allowed 

 to stand some hours. The crystals were filtered off, washed with a little 



* ' Eoy. Soc. Proc.,' this vol. 



VOL. LXXXI. — B. 



K 



