Vol. XXV. September, 1913. No. 4. 



BIOLOGICAL BULLETIN 



A STUDY OF THE EFFECTS OF INJURY UPON THE 

 FERTILIZING POWER OF SPERM. 



NEIL S. DUNGAY. 



CONTENTS. 



Page. 



I. Introduction 213 



II. Materials and general methods 214 



A. Occurrence 214 



B. Collecting 214 



C. Removal of germ cells 215 



D. Culture methods 215 



E. Controls 216 



F. Treatment of sperm cells 216 



G. Cytological methods 217 



III. Outline of development of Nereis eggs 218 



IV. Experiments 220 



A . Upon Nereis 220 



1 . Heat 220 



2. Delay 227 



3. Fresh water 229 



4. Alcohol 230 



5. Sodium hydroxide 231 



6. Hydrochloric acid 232 



7- Cold 233 



B. Upon Arbacia 233 



V. Cytological stud y 236 



A . Normal . 236 



B. Experimental 237 



VI. Discussion 244 



A, The production of defectives 244 



B. Fertilization 252 



VII. Summary 254 



I. INTRODUCTION. 



This paper deals with the results obtained by fertilizing 

 normal eggs with spermatozoa injured by various methods. The 

 results have a bearing upon some of the problems of fertilization. 



213 



