164 W. H, LONGLEY 



than four hundred, almost all of which were distant from the egg 

 less than its diameter, were counted in the immediate neighbor- 

 hood of one two-cell stage. Some were found embedded in masses 

 of granulosa cells which had become detached, and others on the 

 epithelial surface of the tube at the points nearest the egg. If 

 experiments with invertebrate eggs had not failed to show that 

 the egg is able to exert a chemotactic influence upon the sperm, 

 one would readily believe that confirmatory evidence of chemo- 

 taxis appeared here. 



The second polar body 



A second polar body is never found with an ovarian egg. 

 Whenever with such an egg two corpuscles occur, which by their 

 appearance suggest the possibility that they may be first and 

 second polar body, they are invariably associated with a second 

 polar spindle rather than with a female pronucleus. 



The second polar body is in evidence before the sperm head 

 has penetrated far into the egg (figs. 11-12). In early fertili- 

 zation stages, fibres may be found passing from the chromatin 

 of this body to the point at which it was constricted from the egg. 

 The second polar body does not seem to have as dense cytoplasm 

 as the first, nor to hold its definite outline as long. In some cases 

 its chromatin is in several granules, in others in only one. Fre- 

 quently it is possible to tell the two polar bodies apart by the 

 different amount of chromatin which they contain, but when the 

 first polar body's chromosomes have undergone a condensation 

 and those of the second are less compact this criterion fails. Some- 

 times the position of the polar bodies with reference to the female 

 pronucleus, or other evidence outside of the polar bodies them- 

 selves, may give proof of their nature, but in addition to all these 

 cases, there are others where no clue can be found for the classi- 

 fication of the two cells in question. 



