584 FRANK R. LILLIE 



by means of the Barber apparatus, from two or three to over 

 twenty spermatozoa of the star-fish into eggs of the same species. 

 There was never any indication of cleavage. The experiments 

 were hmited owing to interruption of Dr. Kite's work, so that 

 the evidence in this case is not yet wholly conclusive ; but the 

 results indicate the necessity for normal penetration, if the sper- 

 matozoon is to be effective. 



We therefore see a second function of the fertilizin, viz.: to 

 prepare the spermatozoon for exercising fertilization effect in 

 the interior of the egg. The spermatozoori needs itself to be fertilized. 



De Meyer ('11) has observed swelling of the head of the sper- 

 matozoon under the action of egg-extractives, and I have de- 

 scribed the same thing for Nereis ('13). But how such changes 

 intervene in the internal fertilization reaction remains problem- 

 atical. It is improbable that the swelling itself is significant; 

 it is rather to be taken as indication of a more deeply seated 

 physiological change which is essential for the completion of 

 subsequent reactions. 



3. THE LYSIN THEORY OF FERTILIZATION 



Loeb's lysin theory of fertilization may be taken as the type of 

 all theories which postulate that the spermatozoon produces and 

 bears a fertilizing substance. Loeb holds that the spermatozoon 

 causes membrane formation and thus initiates development by 

 virtue of a lysin, and he holds this idea not because he, or some 

 other, has isolated this substance and tested its action, but be- 

 cause the action of the spermatozoon in initiating development 

 resembles the action of certain cytolytic substances, more espe- 

 cially, fatty acids, certain glucosides and the blood of some 

 foreign species. Indeed he holds that all cytolytic agents induce 

 membrane formation, and the action of the spermatozoon is re- 

 garded as merely a special instance. The spermatozoon, accord- 

 int to Loeb, introduces a second substance into the egg whose 

 function it is to inhibit the harmful effects of membrane for- 

 mation. However the effect of fertilization in increasing the 

 rate of oxidation within the egg is due not to a catalyzer intro- 

 duced by the spermatozoon but to the activation of catalyzers 



