1226 METABOLISM OF LIPOIDS, STEROLS, [pt. iii 



for stray traces, it is confined to the yolk and the embryo, i.e. none 

 appears in the white, the amniotic, or the allantoic liquid. His 

 figures for total cholesterol in the whole egg, graphically reproduced 

 in Fig. 391, show a diminution followed by a rise, but the dimensions 

 of the change are not sufficient to warrant a belief in a decomposition 

 followed by a synthesis. They come within the zone of other workers' 

 results, shown in Fig. 389. Apart from this, Kusui confirmed the 

 earlier discovery of a decrease of free and an increase of combined 

 cholesterol. It would seem that the increase of cholesterol esters 

 is not confined to the embryonic body but also takes place in 

 the yolk. 



According to Dam about i-6 mgm. of cholesterol in each yolk is 

 attached in some way to the proteins and cannot be removed by 

 ether extraction unless they are first hydrolysed. No oxycholesterol 

 exists in eggs or embryos. 



12-5. The Relation between Lipoids and Sterols: the Lipo- 

 cytic Coefficients 



We are now in a position to consider the "lipocytic coefficients" of 

 Mayer & Schaeffer. The first is: 



Total cholesterol 

 Total fatty acids 



This was established by Mayer & Schaeffer for the following animals 

 and tissues: 



Electric 



organ Lung Kidney Liver Muscle 



Dog — 20 ID 7 — 



Rabbit — 17 13 8 2 



Guinea-pig ... ... — 15 8 6 7 



Pigeon — 24 98 2 



Eel — II 74 2 



Torpedo ... ... 22 12 — I i 



Thus as a general rule the lung has much more cholesterol in relation 

 to its total fatty acids than the muscle. Mayer & Schaeffer then 

 tabulated the water-content of a number of tissues of different 

 animals, and made the interesting discovery that a parallelism existed 

 between water-content and lipocytic coefficient. Wherever the latter 

 was high, so was the former, and vice versa. This is illustrated by the 

 following table: 



