1228 



METABOLISM OF LIPOIDS, STEROLS, [pt. iii 



is exactly what so many investigators have found. It is instructive to 

 compare this curve for the lipocytic quotient with the standard curve 

 for water-content of the embryo shown in Fig. 220, for not only the 

 general trend, but even the forms of the two curves are the same, 

 both falling rapidly until the 1 7th day, and then coming to an almost 

 steady state. The conclusion that the two processes are related can 

 hardly be avoided, and it ^^^^^ 



must be admitted that, as .lo'r?'^ Cahn 



far as the embryo of the 

 chick is concerned, Mayer & 

 Schaeffer's generalisation is 

 strongly supported. If the 

 subject were not experiment- 

 ally rather difficult, it would 

 be interesting to determine 

 the maximum imbibition of 

 water of which the embryonic body is capable each day, and to 

 find out whether it would obey the equation of Mayer & Schaeffer. 

 This has been done in the case of the lung of the foetal sheep by 

 Faure-Fremiet & Dragoiu (see p. 1573)- 



The other coefficient which they introduced was : 



"F^^'^'^oo 



Days -> 5 



Fig- 393- 



Lipoid phosphorus 

 Total cholesterol 



X 100. 



It ran as follows in adult tissues: 



Whole 

 Lung Kidney Liver Muscle body Investigator 



Dog ... ... 4 2 I I - Mayer & Schaeffer 



Rabbit ...4321- jj >? 



Guinea-pig ... 3 2 i i - ,, ,, 



Pigeon ... 4 2 2 I - >, ,, 



Eel - 2 5 3 - „ „ 



Rat _ _ _ _ 2 Cahn 



Cahn calculated this coefficient from his figures for cholesterol and 

 lipoid phosphorus in the embryonic body, and found it to be very 

 constant throughout development, tending perhaps to fall a little 

 as development proceeded. This is shown in Fig. 393. 



12-6. Cycloses and Alcohols in Avian Development 



As regards ethyl alcohol, which has long been known to be a 

 constant, if minute, component of animal tissues, only one investiga- 



