80 



THE EGGS OF MAMMALS 



TABLE XI 



The Effects of Exposing Freshly Ovulated Rabbit Ova to Various 

 Solutions of Trypsin. (From the Journal of Experimental Zoology) 



* All these ova showed irregular masses of webbed tissue in the perivitelline space. 



The data of these experiments show typical folUcle cell 

 dispersion and also ^^ polar body" formation (Figure 26). 

 These are, however, not true polar bodies but rounded cyto- 

 plasmic masses caused by the action of the enzyme prepara- 

 tion upon the egg surface. Sections of the ova of these 

 experiments showed the ''polar bodies" to be chromatin 

 free. The polar bodies observed by Yamane in his pan- 

 creatin experiments were probably of this nature. The polar 

 bodies formed in his experiments with rat and horse sperm 

 may have also have been false polar bodies due to the 

 strongly digestive action of the heterologous sperm sus- 

 pensions, for, as we have seen, rat sperm suspensions are 

 extremely effective as follicle cell dispersing agents even in 

 very low concentrations. Krasovskaja (19356) believes that 



