SECT. 3] AND ORGANISATION 607 



from the idea originally suggested by Jordan that haemopoiesis 

 was associated with lack of oxygen or accumulation of carbon 

 dioxide, he allowed chick embryos to develop for 24 hours or 

 so, and then, breaking off the shell covering the air-space, immersed 

 the whole egg in water-glass solution so that the respiratory 

 exchange was quite stopped, but incubation allowed to proceed 

 till 96 hours. He then examined the suffocation effects so pro- 

 duced. These were (i) normal body-form only at the anterior 

 end, (2) no allantois, (3) extraordinarily large blood-vessels and 

 anomalous sinuses, (4) constantly recurring fatty necrosis of tissues. 

 Since the circulation of blood had stopped in these embryos, the 

 end-products of metabolism were accumulating in their cells. The 

 enormous amounts of blood found obviously suggested an unusual 

 haemopoietic activity. But the heart, being unable to beat in the 

 toxic anoxaemic blood, allows it to accumulate in the vessels, and, 

 as more blood-cells are continually being formed, sinuses develop. 

 Cessation of the circulation having led to a struggle for existence 

 between the various parts of the body, some may find it possible 

 to live on the rest, and unorganised "anarchistic" or unregulated 

 growth may occur. This is what Byerly actually found in the suf- 

 focated embryos, as regards the formation of blood, btit he did not 

 bring forward any evidence that an unusual quantity of lactic acid 

 was produced in the suffocated embryos, as would have been the 

 case on Warburg's view if one tissue had taken on an anaerobic Hfe 

 and was growing at the expense of the others. Holmes was later 

 unable to repeat these observations of Byerly's on the chick embryo, 

 but the number of her experiments was insufficient to negative 

 definitely Byerly's conclusions. 



In his second paper, he continued the study of "dead" embryos, 

 which he observed to show three types of behaviour. One class 

 remained on the surface of the yolk and showed anarchistic growth, 

 one absorbed liquid to form a bladder-like vesicle on the surface 

 of the yolk, and one sank beneath its surface. Beha\dour of the tissues 

 of embryos of the first class varied according to the age of the embryo 

 at the time when the heart was made to stop beating. If cardiac 

 failure occurred after 4 or 5 days' incubation, only the liver cells 

 and certain of the blood-cells were still proliferating at the end of a 

 week's anaerobiosis. But if the failure took place at 72 hours' in- 

 cubation or less, then, in addition to liver and blood growth, the 



