FACTS AND FACTORS OF DEVELOPMENT 



accomplish this miracle of transforming the 

 fertilized egg cell into the fish, or frog, or 

 man a thing which would be incredible were 

 it not for the fact that it has been seen by 

 hundreds of observers and can be verified at 

 any time by those who will take the trouble to 

 study the process for themselves. 

 A 



FIG. 10. FOUR STAGES IN THE CLEAVAGE OF THE EGG OF THE 

 SHEEP; pb, polar bodies. (After Assheton.) 



