THE FERTILIZATION-REACTION IN 

 ECHINARACHNIUS PARMA. 



IV. A FURTHER ANALYSIS OF THE NATURE OF BUTYRIC ACID 



ACTIVATION. 



E. E. JUST. 



(From the Marine Biological Laboratory, Woods Hole, Mass., and the 

 Zoological Laboratory, Howard University, Washington, D. C.) 



CONTENTS. 



I. Introduction ................................................... 280 



II. Observations on the cytolysis of butyric acid treated eggs .......... 281 



A. The method ................................................ 284 



B. The observations ............................................ 284 



C. Discussion .................................................. 288 



III. Observations on the duration of fertilization capacity in butyric acid 



treated eggs ............................................. 291 



A. The method ................................................ 291 



B. The observations ............................................ 292 



C. Discussion .................................................. 294 



IV. General Discussion ............................................. 296 



A. The cytolysis theory of Loeb ................................. 298 



B. The rhythmical changes of cell division ........................ 301 



C. The fertilizin theory of Lillie ................................. 303 



V. Literature cited ................................................ 304 



I. INTRODUCTION. 



In a previous communication (Just, 'iQc) the writer has shown 

 that the butyric acid activation of Echinarachnius eggs as shown 

 by membrane lifting is complete since these eggs (following in- 

 semination) cannot be fertilized with sperm even after removal 

 of the membranes. With membrane lifting, therefore, the eggs 

 undergo an irreversible change. Those eggs, however, which 

 following exposure to butyric acid at or below the optimum length 

 of time for perfect membranes fail to show membranes are not 

 activated because they are still capable of complete fertilization 

 yielding on insemination normal membranes, cleavage, and larvae. 

 Likewise, eggs which have had an exposure to butyric acid be- 



28f) 



