FERTILIZATION REACTION IN ECHINARACHNIUS PARMA. 5! 



cessful treatment with artificial agents it must be handled with 

 extreme care to insure uniform results. 



2. Echinarachnius eggs that form membranes through butyric 

 acid treatment are completely activated since such eggs respond 

 to subsequent hypertonic sea-water treatment with develop- 

 ment that closely simulates the normal, and since eggs under- 

 or over-exposed to butyric acid and which do not form mem- 

 branes never form membranes following hypertonic sea-water 

 treatment nor do they develop at all normally. Activation, 

 again, must be regarded as complete since butyric acid eggs with 

 membranes fail to develop after insemination even though the 

 membranes be removed as soon as formed ; in this they resemble 

 fertilized eggs or fragments thereof that faiy t 

 Finally, these butyric acid treated eggs with membjanes fail 

 to give the fertilizin test as rapidly as do fertilized^J^ We 

 must, therefore, conclude that activation is as o 

 with butyric membranes as in eggs with fertilization 



It is interesting to note that Loeb found that his sla-urchiir 

 eggs after butyric acid membrane formation were capable of 

 fertilization provided he had removed the membranes by sha-king. 

 Lillie, however, found that Arbacid\e^gs after membrane forma- 

 tion by butyric acid cease to produce fertilizin as do fertilized 

 eggs. Moore confirmed Lillie's butyric abservation on Arbacia 

 and also discovered that eggs with butyric membranes are in- 

 capable of fertilization. To Loeb, complete membrane forma- 

 tion by butyric is an incomplete activation ; to the workers with 

 Arbacia and Echinarachnius eggs membrane formation by butyric 

 acid is a complete activation. In initiation of development, 

 therefore, the egg gives a similar response both to the artificial 

 agent and to the spermatozoa. This, however, does not entail 

 subscription to the famous "lysin theory." 



It is now some twenty years since the work on artificial par- 

 thenogenesis began. During this time eggs have been subjected 

 to every kind of agent imaginable, a vast amount of literature 

 has been produced, and many guesses have been made on the 

 basis of this work as to the nature of the fertilization reaction. 

 This work on artificial parthenogenesis constitutes one of the 

 important chapters in the history of modern biology and no 



