244 WHITMAN. ' [Vol. I. 



The point of chief interest here is the fact that attraction 

 between the ooplasm and the spermatozoon can manifest itself 

 at a distance. Difficult as it is to explain the mechanism of 

 such action, the fact itself is so conclusively established that 

 we are compelled to accept it. At first sight, the fact appears 

 to stand entirely alone ; but there is something very closely 

 analogous in the attraction between the pronuclei. They cer- 

 tainly attract each other at very considerable distances ; but it 

 may be a question whether they act directly on each other, or 

 through the medium of the ooplasm which bridges the distance 

 between them. That the action of the pronuclei upon the 

 ooplasm — whether on the hypothesis of currents or that of 

 polar attraction — cannot account for the behavior of these 

 bodies toward each other is conclusively shown by the fact that 

 supernumerary male promiclei do not unite, although they do 

 develop astral radiations. If the influences which manifest 

 themselves in these astral lines are not competent to account 

 for all the movements of the pronuclei, how can we escape 

 the conclusion that the pronuclei act directly on each other? 



The necessity of recognizing two distinct kinds of attraction is 

 thus made very clear. On the one hand, we have the direct 

 action of one nuclear body upon another nuclear body, which 

 we have called nuclear attraction ; and, on the other, the 

 action of nuclear bodies on the ooplasm, which manifests itself 

 in astral lines, and to which we have given the name centrip- 

 etal attraction. The cone of attraction in Asterias may be 

 regarded as a manifestation of centripetal attraction under 

 exceptional conditions ; for, although the cone moves toward 

 the spermatozoon, this fact does not exclude the idea of recip- 

 rocal attraction. Although, from the nature of things, we do 

 not expect to see the &gg move, as a whole, towards the sper- 

 matozoon, there are, at least, very strong grounds for believing 

 that it attracts at the same time that it is attracted, and that its 

 attractive influence is always felt before- actual contact takes 

 place. 



I am fully aware that most writers hold that the sexual 

 products are brought together, not by attractive influences, but 

 by the impelling action of the tail of the spermatic body. Fol 

 is so strongly impressed with this belief that he examines all 

 other hypotheses before accepting that of attraction at a dis- 



