No. 581] ENTRANCE OF THE SPERMATOZOON 283 



common form was a stereoblastula. In "the second Ii fertilization there 

 were a few abnormal prismatic plutei, while the majority were gastrulae. 

 The third fertilization resulted in extremely abnormal ciliated types. 

 The fourth and fifth did not proceed beyond abnormal cleavage stages. 



From this and similar experiments Lillie draws the fol- 

 lowing conclusion : 



The eggs have evidently lost something which affects their power of 

 fertilization. Table 3 shows the measure of loss of the sperm agglu- 



factor in the result. The l„>s ..I" mh.-r Mil»tan.-..> may also combine in 



As a matter of fact, fertflizing power is gradually lost with decrease of 



It seems to the writer that in these experiments the 

 power of being fertilized was gradually lost by the death 

 of the eggs. And an additional justification of this criti- 

 cism is given by the following fact, that if we deprive 

 fresh eggs of purpuraius permanently of their power of 

 giving off " fertilizin " their power of being fertilized is 

 not only not lost but is entirely unaltered. The writer 

 has shown that if the eggs of purpuraius are treated for 

 two or three minutes with a mixture of 50 c.c. of sea water 

 + 3 c.c. of HC1 (whereby the jelly surrounding the egg 

 is dissolved) and if the eggs are washed they give no 

 trace of a fertilizin reaction but 100 per cent, of the eggs 

 can be fertilized. 30 



It might be argued that the supernatant sea water from 

 these eggs had not lost all power of causing agglutination 

 of the sperm. This the writer must deny but for argu- 

 ments' sake he will admit that a trace near the " psycho- 

 logical limit " might have been overlooked where a " fer- 

 tilizin " partisan might have declared that he still could 

 perceive a faint indication of a " fertilizin " reaction. 

 In that case only a few eggs should have been fertilized— 

 the fertilizin theory rests on this assumption ; in reality, 

 however, practically one hundred per cent, were fertilized 

 in every case (provided the eggs had not been lying in the 

 see water too long, i. e. } more than a day or two). 



