[004 



CARBOHYDRATE METABOLISM 



[PT. Ill 



like the entire Ggg, Fig. 268, in which the glucose is shown expressed 

 as milligrams per cent, of yolk and white and plotted against time, 

 is perhaps a better indication of what is going on. It demonstrates 

 that, although both fractions of sugar fall markedly, there is a sort 

 of cross-over in the middle of development, the yolk continuing at 

 75 mgm. per cent, and the white dwindhng away to nothing. If a 

 passage of glucose into the yolk takes place, it must be by way of 



^':^,''^^lGadaskina 



Vlaci;mirov&,Schmidbb 

 Tomiba 



Sakuraqi 



Yolk 



Whlbe 



Yolk 



White 



Yolk 



White 



Yolk 



White 



Yolk 



Yolk&,Whibe(ld2umi) 



Yolk8,Whibe(Sakuragi) 



Yolk 



White, 



White (Mbrner) 



Whibe(Pavy) 



White {By waters) 



the chick's blood-vessels. There is a piece of experimental evidence 

 against it, for in 1921 Tomita injected glucose into the air-space of 

 unincubated eggs. The idea had previously occurred to Pouchet & 

 Beauregard, who, as far back as 1877, had injected | gm. of sterile 

 "crystallised cane-sugar" into hen's eggs. Development was normal 

 up to 13 days, but there was an odour of lactic fermentation. "Nous 

 n'avons pu constater", they said, "la presence du sucre interverti 

 dans I'albumine. £tait-il demeure dans son etat ou avait-il disparu 

 soit dans le vitellus, soit consomme par I'embryon?" Tomita's re- 

 searches were more enlightening: 



