CHAPTER IV 



THE PHYSIOLOGY OF THE SPERMATOZOON 

 I. INTRODUCTION 



What are the forms of behavior of flagellated sper- 

 matozoa? What conditions are optimum? What 

 changes in environment are significant? Such ques- 

 tions are vital for the study of the physiology of fertili- 

 zation; but the subject has ftot been studied with the 

 attention that its importance deserves. Such knowl- 

 edge as we possess demonstrates that spermatozoa are 

 exceedingly sensitive organisms in certain respects. 

 With reference to the reaction (i.e., H ion equilibrium) 

 of sea-water, for instance, the spermatozoa of certain 

 marine forms are as delicate indicators as we possess. 

 The general belief appears to be that in the medium 

 in which fertilization takes place spermatozoa are in a 

 condition of ceaseless random activity; but are their 

 movements entirely undirected ? Do they indeed differ 

 from other organisms in exhibiting no directiveness 

 of behavior ? To what stimuli do they respond ? 



II. GENERAL 



Spermatozoa are almost invariably immobile in the 

 testis and the efferent ducts. They become active in 

 the medium in which insemination takes place. Among 

 marine animals there are great variations in this re- 

 spect. Thus the spermatozoa of most annelids and 

 . sea urchins and many other forms become exceedingly 



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