432 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN' 



studies show that eggs of Arbucia and of Nereis gWe off substances 

 that produce various visible effects on the sperm of the respective 

 species. There is "stimulation of intense acti\'ity, which is of 

 brief duration; (2) an orienting effect expressed in positive chemo- 

 taxis; (3) an agglutinating action; (4) following these effects more 

 or less complete paralysis of sperm" ('13, p. 554). The so-called 

 agglutination, however, is held to be an indication of a chemical 

 action that is necessary for union of ova and sperms. The par- 

 ticular "isoagglutinin" produced by eggs is called " fertilizin." Its 

 action is regarded as similar to that of "amboceptors" in that it 

 is considered a necessary link in fertilization, combining first with 

 sperm receptors and then with the egg receptors. The function 

 of fertilizin is not that of an antibody giving immunity, but rather 

 that of a sensitizer which makes invasion and fertilization possible. 

 It does not appear whether the agglutination phenomena here 

 observed bear a close or a superficial resemblance to the aggluti- 

 nations of immunity reactions. 



In producing evidence in favor of the chemotactic influence of 

 egg secretions involving the liberation of some such substance as 

 fertilizin, Lillie has emphasized the importance of internal condi- 

 tions determined by a particular and specific constitution of the 

 indi\'iduals of a species which are fully self- and cross-fertile. 



The discussion of self-sterility by Lillie ('13a, p. 573; '16, p. 51) 

 and his postulated causes of inhibition of fertilization ('136, p. 528) 

 are hardly adequate for the known facts. Lillie is perhaps misled 

 by a misunderstanding of the facts, for he states in reference to the 

 phenomena of self-sterility "in species when this occurs the egg 

 and sj)erm of the same individual are sterile inter se though fertile 

 with those of all other individuals" ('16, p. 51). That this is not 

 necessarily the case has been well shown by Correns whose data 

 in respect to the variations of cross-sterility are quite like those 

 which the writer has reported for Cichoriiim. Furthermore, the 

 specificity of fertilization according to Lillie involves complete 

 cross-compatibilit\- between all individuals of a species, and also 

 full self-compatibility of hermaphrodites. This is hardly com- 

 parable to the "individual specificity" of self-sterile hermaphro- 

 dites whose self-sterility invoh-es an incompatibility of sex cells 

 equal to that between two different and cross-sterile species. 

 Sterility and fertility in and between indi\iduals and species are 

 in exidence and a theory of speciruity must provide for both. 



