130 



Messrs. Ellis and Gardner. Origin and [Jan. 15, 



absolute alcohol and weighed. In all cases these crystals were colourless, or 

 nearly so, and melted approximately correctly. The filtrate and washings 

 were separately measured, and corrections, which had been ascertained by 

 previous experiments, made for the solubility of cholesterol benzoate. When 

 cholesterol benzoate was crystallised from absolute alcohol the mother liquor 

 at 21° C. contained - 12 per cent. When, however, ready formed crystals 

 were shaken for a short time with alcohol at 20° C. and filtered, the filtrate 

 was found to contain only - 04 per cent. When a number of eggs or chicks 

 were analysed together, the unsaponified residue was crystallised from 

 alcohol, and as much pure cholesterol as possible was isolated, melting at 

 145° — 147° C. The mother liquors were then evaporated to dryness, 

 benzoylated in a pyridine solution as described above, and the benzoate 

 weighed. The soaps precipitated on saponification were collected together in 

 two lots, comprising respectively the total amount obtained from all the eggs 

 examined, and the total amount obtained from all the chicks. These were 

 separately mixed with about twice their weight of salt, water added, and 

 after evaporating to dryness were thoroughly extracted with ether. In 

 neither case could any appreciable quantity of cholesterol be isolated. 



In Table I the analysis of eight eggs is given, and in Table II the analysis 

 of eight chicks. 



It is obvious from these figures that no increase in the quantity of 

 cholesterol takes place during the change from ovum to newly-hatched chick, 

 the average percentage of cholesterol in eggs being 03827, and in chicks 

 03693, or in terms of the weight of the original eggs 03172. The same 

 result follows, no matter whether we take the figures for crude unsaponifiable 

 matter, or those for pure cholesterol. 



At first sight it would appear that a loss of cholesterol occurs, but taking 

 into account the facts that the difference between the average percentage of 

 cholesterol in eggs and chicks (column e) — - 066 — is of much the same order 

 of magnitude as the average deviation from the mean in the two cases, 

 viz., - 057 for eggs and 0"075 for chicks. That individual eggs differ 

 considerably in the loss in weight which takes place during incubation, that 

 there is no reason to suppose that the proportion of yolk to white in 

 different eggs is very constant, and that the method of estimation of 

 cholesterol does not possess a very high degree of accuracy, it would seem 

 probable that no change in the quantity of cholesterol takes place, and that 

 all the cholesterol of the egg is contained in the newly-hatched chick. In 

 order to obtain a more accurate value for the cholesterol content of eggs and 

 chicks, six eggs and six chicks were analysed together, as the greater the 

 quantity of cholesterol weighed in an analysis the more accurate is the 



