220 PROBLEMS OF FERTILIZATION 



at least, are agglutinated together by egg secretions of 

 the same species. This phenomenon is definitely tissue 

 specific, as I have already pointed out. At the present 

 time the extent of specificity between species has been 

 inadequately investigated. This subject has been dis- 

 cussed in chapter iv, and it would appear that there may 

 be a sufficient degree of specificity there to account for 

 the specificities in fertilization, with the exception of 

 self-infertility, which has not been investigated from 

 this point of view. The relation of sperm agglutina- 

 tion to the fertilization reaction itself is considered in 

 chapter vii. 



While it is by no means certain that specificity in 

 fertilization depends upon specific agglutination of the 

 spermatozoon to the egg, yet I think it must be 

 admitted that the latter phenomenon furnishes an 

 important clue for the further analysis of the problem 

 of specificity in animals. Until this is made, the 

 temptation to speculate further along these lines should 

 better be resisted. 



REFERENCES 

 BALZER, F. 



1910. "Ueber die Beziehung zwischen dem Chromatin und 

 der Entwicklung und der Vererbungsrichtung bei 

 Echinodermenbastarden," Arch, fiir Zellforschung, 

 Band 5, pp. 497-621. 



BATAILLON, E. 



1906. "Impregnation et Fecondation," Comptes rendus de 



I'Acad. des Sci., T. 142, pp. 1351-53. 

 1909. "L 'impregnation heterogene sans amphimixie nucle- 



aire chez les amphibiens," Arch, fiir Entwickelungs- 



mech., Band 28, pp. 43-48, 



