438 



METHOD OF CHORIO-ALLANTOIC GRAFTING 



CH0fllO-*LLII*T0IC kEMBRiHt 

 tMN I OH 



L»f OF SHELl. 



SHELL MEMBRtHE 



LAYERS Of THE SHELL- 

 SHELL MEMefidHE- 

 CH0filO-*LL*HTOIS' 



»IL«KI0IC 8L0OC VESSEL 



PIPEHE USED TO 



TR4HSFER THE 



GR»FT THROUGH THE 



SHELL OPEHIMG 



Diagram illustrating the method of chorio -allantoic grafting. Host 

 embryo is generally incubated for 8 to 9 days, the graft may be any 

 anlage (e.g. , the limb bud of 72 hour stage). The graft Is generally 

 recovered at about the 19th day, just before the time of hatching of 

 the host when the membranes begin to dry up. 



Thhough porous shell 

 Carbon 



Oxygen 



In 



Shell membrane 

 Seroso 



Schematic diagram showing the arrangement of main circulatory channels in a young chick embryo. 

 The sites of some of the extraembryonic interchc "ges important in its bioeconomics are indicated by 

 the labelling. The vessels within the embryo carry food and oxygen to all its growing tissues, and 

 relieve them ofthe waste products incident to their metabolism. Abbreviations: A. O. M. , omphalo- 

 mesenteric artery; V. CM. , omphalomesenteric vein. 



Prom Patten, B. M. - 1951 - Am. Nat. 39:225 (with permission) 



