52 E. E. JUST. 



mean part among the many brilliant achievements of Loeb which 

 aside from their inherent value have another claim to distinc- 

 tion their stimulating effect on the new experimental zoology. 

 But artificial parthenogenesis is not fertilization. And it is indeed 

 unfortunate that the term artificial parthenogenesis ever had 

 that connotation. Thus we read of "fertilization membranes" 

 by this or that chemical, "fertilizing agents," "chemical fertili- 

 zation," etc., when we know that there are eggs that will respond 

 to very slight changes in the environment. The eggs of Am- 

 phitrite, Asterias, Nereis, etc., for example, will respond simply 

 to agitation. Artificial parthenogenesis per se is too significant 

 to masquerade as fertilization. The processes initiated in artificial 

 parthenogenesis and fertilization probably are the same. But 

 to argue that the sperm carries a lysin because a host of agents 

 activate the egg is bad logic. It is far simpler to postulate that 

 the egg contains the necessary mechanism for development. 

 Such a postulate embraces not only artificial parthenogenesis 

 and fertilization, but also the widely occurring and real partheno- 

 genesis. Artificial parthenogenesis teaches us that the egg is a 

 highly irritable cell that will respond to various agents; it has 

 placed us but little nearer a solution of the fertilization problem 

 than we were twenty years ago. One might as easily deduce 

 from the contraction obtained on a curarized muscle with any 

 one of a number of stimuli the nature of the nerve impulse as to 

 formulate a theory that since CO 2 , or any other of a number of 

 agents induces development fertilization is due to a lysin carried 

 by the sperm. 



Nor yet have purely morphological hypotheses proved satis- 

 factory. The Boveri hypothesis as its predecessors is no longer 

 considered adequate; and such deductions as those of Meves lead 

 only to absurdities. 



Lillie's assumption that the egg in its fertilizable condition 

 contains a substance (fertilizin) which needs merely to be acti- 

 vated is logical and is based on observation and experiments 

 which themselves, theory aside, excite admiration. Future work 

 will determine how much this theory has helped toward a solu- 

 tion of the fertilization problem. 



