SECT. 12] GYGLOSES, PHOSPHORUS, SULPHUR 1223 



the beginning of development (i-86 per cent, of the dry weight) and 

 282 mgm. per egg at 18 days. The admitted positive balance was 

 probably not significant. The later work of Dam was designed to 

 answer this question. In one of her experiments, the cholesterol per 

 egg was 245-0 mgm., and that of the 2ist-day embryos 263-5 mgm.; 

 in another series, that of the undeveloped eggs was 310-0 mgm. and 

 of the hatching chick 343-0 mgm. In the former case the increase 



■ Total cholesterol (Parke) 

 ♦ " " (Mendel ^Leavenworth) 



^ -W » " (Roffo fie Azaretfi) 



A " " (Dam) 



4- » » (Cahn) 



200 



▼ Total cholesterol | 



vFree « / Kusui 



^Cholesterol estersj 



• Total cholesterol ^ 



O Free " yMueller 



® Cholesterol esters] 



on the initial value was 7-6 per cent, and in the latter case 10-6 per 

 cent., and these amounts, though not considerable, were of the same 

 order as those found by Thannhauser & Schaber, and were invariably 

 found by Dam. In a subsequent paper, however, she gave further 

 figures which showed no increase. 



Analogous results to these were obtained by Mueller in 1915, 

 who investigated the free and combined cholesterol content of the 

 whole egg throughout incubation. From his figures, which are 

 plotted in Fig. 389, it can be seen that the total cholesterol in the 

 egg remains at a steady level throughout incubation. But the most 



