8a THE PSYCHIC LIFE 



able circumstance here; there are also involutions and 

 intricacies in the path to be followed in reaching the 

 ovule. In this connection an interesting observation 

 has been made upon the silk-worm. " At the moment 

 of conjugation the male deposits its seminal fluid in a 

 special sac, the copulatory sac. The day following, 

 this sac, which was distended by the sperm, is com- 

 pletely flaccid, and nearly all the spermatozoids have 

 traveled out into another sac, which opens into the 

 oviduct opposite the first one, and there they wait to 

 fecundate the ovules as they pass by. Now, the walls 

 of the copulatory sac have no contractile power, and 

 the passage of the spermatozoids from one sac into 

 the other can be attributed only to a spontaneous 

 movement. Further, a fact that well seems to verify 

 this, is, that there still remains in the copulatory sac 

 a few mis formed seminal elements, deprived of the 

 power of locomotion." * 



Let us now note what happens at the moment 

 when spermatozoid and ovule come in contact with 

 one another. The successive phenomena then taking 

 place have been carefully studied by Fol in his work 

 upon the star-fish (Aster ias glacialis). The ovule has 

 no enveloping membrane; it it is covered about only 

 by a mucous layer, soft and flaky. The spermatozoids 

 come up in great numbers and push forward into this 

 layer; at this point they are all brought to a halt and 

 become entangled among each other with the excep- 

 tion of one, which, more speedy in its movements, out- 

 strips the others and arrives within a short distance of 

 the surface of the vitellus (or protoplasm of the ovule). 

 At that moment, and before any contact whatever, there 

 results a curious phenomenon of attraction between the 



* Balbiani, Comptes Rendus de /' ' Acad, des Sciences, 1869. 



