BREEDING HABIT^ OF ALBINO RAT 



303 



The next stage we were able to obtain is shown in figure 11. 

 This is an ovarian egg with the first polar body and the second 

 polar spindle. As in the case of the mouse, the nuclear material 

 is never gathered into a resting stage between the time of exti-u- 

 sion of the first polar body and the formation of the second 

 polar spindle. 



The first polar body is rarely seen in eggs outside of the ovary, 

 but there is absolutely no reason to doubt that it is always 

 formed, since it is almost invariably present beside normal ova- 



Fig. 6. Reconstructions of three spindles showing gradual rotation from the 

 paratangential position (a), through (6), to the radial position (c). 



rian eggs, possessing a se'cond polar spindle. Even in the ovary, 

 however, its protoplasm displays its characteristic tendency to 

 uiidergo rapid disintegration. In such fully matured eggs as 

 have failed to escape from the ovary and are just starting to 

 degenerate, as well as in those about to be discharged, the second 

 polar spindle may be sharply defined, yet a careful search fails 

 to reveal a trace of the first polar body. The chromatin in the 

 first polar body is always scattered, and when first formed this 



