148 CARL RICHARD MOORE. 



develop. The cytoplasm is incapable of responding to the 

 influence of the sperm. Practically the same thing has been 

 shown for the starfish egg by the studies of Delage on merogony. 



Can the failure of the butyric treated eggs to respond to the 

 presence of sperm be explained in the same manner and if so 

 what is the physiological condition of the egg that causes its 

 behavior? Obviously we shall have to examine very closely the 

 condition of the egg at the close of the activation process induced 

 by butyric acid treatment. 



A. Optimum Exposure to Butyric Acid. We will turn our 

 attention to the point in the fertilization curve (Fig. I, 20 

 seconds) at which we obtain membranes surrounding the eggs 

 that are indistinguishable from those produced as a result of 

 fertilization. The membranes are comparatively of the same 

 size as those produced at fertilization ; the hyaline layer appears 

 shortly after the acid treatment and so far as one is able to 

 judge, the membranes in the two instances are morphologically 

 identical. The production of membranes in both cases has been 

 effected by the egg; certain processes have been set in motion 

 by two different activating agents and in each case we have 

 obtained distinct membranes. Development proceeds in the 

 case of fertilization, but in artificial parthenogenesis usually it 

 does not go farther unless the eggs are subsequently treated with 

 hypertonic sea water. Many agents may be utilized in causing 

 eggs to produce membranes but not any of them allow the 

 egg to reach the stage of swimming larvae unless the treatment is 

 followed by hypertonic sea water or other secondary treatment. 

 Evidently the only common factor in the two series of events is 

 the egg itself. It is inconceivable that development could 

 proceed after such a variety of agents as may be used without 

 passing through at some time some of the same conditions as 

 does the normally fertilized egg. 



Immediately or within a short time after membrane produc- 

 tion in fertilization (as we have mentioned) changes in the 

 physiological state of the cytoplasm have rendered it incapable 

 of further response to a spermatozoon. Does the same condition 

 exist in case of membrane production by butyric acid or is the 

 absence of fertilization at this point merely due to the presence 

 of the membrane as Loeb has suggested. 



