252 NEIL S. DUNGAY. 



similar influence. It is even conceivable that nervous states 

 may be able through alteration of somatic metabolism, to affect 

 the germ cells. Many other possible causes of abnormality 

 might be mentioned. But speculation is useless at this time and 

 experimentation is needed. A large field for investigation is 

 opened up and the results of experiments in this field cannot fail 

 to be of interest to the student of eugenics. The sociological 

 application of the observations here recorded is sufficiently 

 obvious. 



B. Fertilization. The results of these experiments are com- 

 pletely in accord with those given by F. R. Lillie ('n and '12). 

 So far as my observations extend they are practically identical 

 with those given by Lillie. He finds that if the attached sperm 

 cell is removed by centrifuging, the processes of jelly formation and 

 maturation go on in a normal manner, though cleavage does not 

 result. My experiments demonstrate that if the sperm is injured 

 so much that it fails to enter the egg, essentially the same results 

 are secured. This fact again supports the view expressed by 

 Loeb ('09), Lillie ('11 and '12) and Bataillon ('12) to the effect 

 that at least two factors are involved in the process of fertiliza- 

 tion. The first is concerned with membrane formation and, in 

 itself alone, is insufficient. Certain cytoplasmic changes such as 

 the rearrangement of the yolk granules are also produced by the 

 initial stimulus. Since slight stimuli cause jelly formation and 

 maturation, pricking as in Bataillon's experiments is probably 

 sufficient to produce these changes. Certainly it is difficult in 

 Nereis to see any action of the sperm beyond the attachment of 

 the perforatorium, which is responsible for the early changes in 

 the egg. In Nereis it is evident that maturation may take place 

 in the absence of membrane formation if the stimulus given by 

 the sperm is sufficiently light. The second factor has to do w r ith 

 the internal stimulus. It is a difficult matter to determine at 

 just what stage fertilization is complete. In all cases which I 

 have observed, the formation of a fertilization cone is succeeded 

 by the entrance of the sperm head and by the formation of the 

 first cleavage spindle. The internal stimulus is not yet com- 

 pleted, even in the case of fertilization by a normal sperm cell at 

 the time when the fertilization cone is formed. This is shown in 



