ioo6 



CARBOHYDRATE METABOLISM 



[PT. Ill 



in Fig. 269, is taken from the averaged estimations of Idzumi and 

 Sakuragi, whose values closely agree. 



Before discussing Fig. 269 further, the glycogen in the whole egg 

 and in the embryo must be considered. Glycogen has been estimated 

 in the embryo by Idzumi and Murray, and their figures agree well^. 

 They are shown in Fig. 270. 



35 p o Glycogen in whole egg(ldzumi) 



© Glycogen in whole eqgCSakuragi) 

 e Glycogen in embryo (Murray) 

 ® Glycogen in embryo(Sakuragi) 

 Glycogen in remainder o 



Days ->■ 5 



From these data it is simple 

 to calculate the non-glycogen 

 sugar in the embryo, and this 

 is shown in Fig. 271 in its rela- 

 tion to the free sugar in the 

 whole egg. It is seen that the 

 rise in free sugar in the whole 

 egg at the end of incubation 

 goes almost exactly parallel 

 with the rise of non-glycogen 

 sugar in the embryo, maintain- 

 ing a distance of about 60 mgm. from it. Thus at hatching there 

 are about 50 mgm. of free sugar still remaining unabsorbed in 

 the yolk-sac and presumably to be absorbed in the first few days of 

 post-natal life. 



Since the free sugar in the embryo (or, more properly, the non- 

 glycogen sugar) rises parallel in the last 10 days with the free sugar 

 in the egg as a whole, it is 

 evident that the free sugar out- o 

 side cannot be the source of the 1 200^ 

 free sugar inside, or, if it is, it 

 must be constantly replenished 

 from some other kind of carbo- 

 hydrate. During this time the 

 total carbohydrate outside (see 

 Fig. 265) is steadily falHng, and 

 loses indeed in the last 10 days 

 160 mgm., during which time 

 the embryo gains a total of 1 10 mgm. The difference must be either 

 burned or transformed into some other substance, possibly cyclose. 



1 Also subsequently by Vladimirov & Danilina, whose curve is almost exactly super- 

 imposable on that for the embryonic body in Fig. 270. Log. glycogen, they found, gives 

 a straight line when plotted against log. age. 



Free glucose in whole egg 

 o Idzumi 

 ® Sakuragi 



a Averaged standard curve 

 O Bernard i^Dastre in 1879 

 Non glycogen glucose in embryo 

 o Needham 



Days ^ 5 



Fig. 271. 



