198 H. B. GOODRICH. 



tion of the polar bodies and in the second series (Table II.) to 

 note possible cleavage. In all but two of the sixty eggs the 

 polar bodies formed. I am inclined to think that as these two 

 were among the earlier ones observed in this case the negative 

 record may be due to faulty observation. Also in only three 

 cases and one of these from a clearly polyspermic lot of eggs was 

 cleavage observed. The time of removal varied from i% 

 minutes to 13^ minutes after insemination. It is impracticable 

 to remove the sperm in most cases earlier than two minutes after 

 insemination as it is difficult to discriminate between spermatozoa 

 lying against the egg and those that have effected an attachment. 

 The average of elapsed time from insemination to removal was 

 6.2 minutes and in sixteen cases the spermatozoon was removed 

 in less than 4 minutes after attachment, and in five cases in less 

 than 3 minutes. It seems therefore clear that in so far as 

 maturation is concerned, the full stimulating effect of the sperma- 

 tozoon is effective within a very few minutes after attachment 

 and quite possibly it is only a matter of seconds. 



The results clearly support the concept that the first phase of 

 activation of the egg-membrane formation and maturation is 

 initiated by the spermatozoon which "activates a substance, or 

 ferment-like bodies, contained within the egg" (Lillie, '19, p. 

 159), rather than by the continuous introduction of some lysin- 

 like substance through the slender perforatorium. For it seems 

 improbable that the spermatozoon could introduce in less than 

 two minutes through the perforatorium which has a cross section 

 area of perhaps one ten-millionth of the surface area of the egg, 

 a sufficient amount of material to take part in reactions through- 

 out the egg. It should, however, be noted that under certain 

 conditions (heating, Just, '15) it is possible to initiate jelly forma- 

 tion without maturation following. This may be taken to indi- 

 cate that a lesser stimulus gives a lesser result and possibly if it 

 were practicable to remove the sperm more promptly that jelly 

 formation only would result. On the other hand in the cited 

 case we may be dealing with a stimulus differing in kind rather 

 than in degree. It should also be noted that these results are 

 not at variance with the concept that cortical changes form an 

 all important intermediate step in the activation of the egg. 



