SECT 7] 



OF EMBRYONIC DEVELOPMENT 



997 



of various developing embryos. 



Investigator 



Murray; Needhz 



4-0 Barthelemy & Br 



net; Needham 



Gortner; Tangl 



Farkas 

 Gortner; McCk 

 don 



principally carbohydrate by Bohr, who obtained a regularly high respiratory quotient Sommer & Wets 

 least 0-90) Bohr 



— i3'8 5'9 ? — 60-0 30-0 — 55-0 60-0 Greene; Miesche 

 1-24 2-1 1 3-71 5-31 ? <io-o 64-0 — i8-7 46-0 Tichomirov; Kel 



— 0-039* ? 0-031 — loo-o — — 15-0 — Dakin & Dakin 



from oxygen consumption. 



lived in the same style it would need an ^gg vastly larger than its 

 present size to contain its physiological sugar solution. The fat of the 

 avian egg is tabloid food. 



The active autohegemonic powers of growth which the embryo 

 has been shown to possess by the experimental embryologists might 

 seem to favour the embryogenic hypothesis. In its support could also 

 be adduced the fact that, during the protein period in the avian 

 egg, there is plenty of carbohydrate being absorbed in the bound 

 form of ovomucoid. It will be seen in Section 8-2 that the free 

 sugar — probably the only carbohydrate fraction burnt by the embryo 

 — does not entirely disappear until the 12th day of development. 

 Yet, as Fig. 261 shows clearly, it is between the 8th and the 9th day 

 that the peak of utilisation of protein occurs.^ The embryo then by 

 no means awaits the exhaustion of its carbohydrate supplies before 

 beginning to combust protein. This fact is strong evidence in favour 

 of the view that the embryo and not the supply of food at its disposal 

 is in command of the situation. In order, however, to make more 

 certain of this, I carried out some injection experiments. Eggs were 

 injected with a solution of glucose containing 500 mgm. per c.c. By 

 injecting into the air-space the mortahty of embryos is much reduced. 

 As will be seen from Fig. 263, no significant effect was produced upon 



^ Moreover, at that moment the egg also contains about 140 mgm. per cent, of glucose 

 in the bound form of ovomucoid. 



