SPERM FILTRATES AND DIALYZATES. 



THEIR ACTION ON OVA OF THE SAME SPECIES. 1 

 MYRA MELISSA SAMPSON, 



DEPARTMENT OF ZOOLOGY, UNIVERSITY OF MICHIGAN, AND SMITH COLLEGE, 

 A. A. U. W. BOSTON ALUMN/E FELLOW. 



I. Introduction 301 



II. Methods 303 



III. Properties of preparations 307 



IV. Potency of preparations on ova of the same species 310 



a. Arbacia punclidata 310 



b. Strongylocentrotus purpuratus and Strongylocentrotus franciscanus . 319 



c. Nereis limbala 321 



V. Filtrates as factors in parthenogenesis 322 



VI. Filtrates as factors in fertilization 327 



VII. Test of filtrates for a sperm fertilizing and agglutinable substance 330 



VIII. Discussion 331 



IX. Summary 335 



INTRODUCTION. 



The idea persists that spermatozoa bear a specific substance 

 which is essential in fertilization. Yet all attempts to extract 

 from spermatozoa a substance which will cause development of 

 ova of the same species have failed or have been open to grave 

 criticism. It is now possible to avoid certain errors which 

 invalidated the results of these investigations. The experiments, 

 to be reported here, were undertaken to determine whether, by 

 processes of filtration and dialysis, solutions can be obtained 

 from living sperm which will effect activation and development 

 of ova of the same species. For interesting me in this problem 

 and for invaluable aid in its solution I am indebted to Dr. Otto 

 C. Glaser. 



The experimental work was carried on during the summers of 

 1919-1922 at the Marine Biological Laboratory at Woods Hole, 

 Massachusetts, and from December until June 1920-1921 at the 



1 Thesis submitted in partial fulfillment of the requirements for the degree of 

 Ph.D. at the University of Michigan. Contributions from the Department of 

 Zoology, Smith College, No. 138. 



301 



