

Fig. 7. Brain of a 2yi>-day chick embryo whicti had received 1^00 r of x-rays 1 1 Va 

 hours preceding fixation. Lumen is at the right. Newcomer fixative; May-Griinwald 

 and Giemsa stain. X 900. 



Fig. 8. Neural tube of a 2'/;- to 3-day chick embr>'o which had received 200 r of 

 x-rays H'/j hours previously. Newcomer fixative: May-Griinwald and Giemsa stain. 

 X 1000. 



87 



