FERTILIZATION AND EGG-SECRETIONS. 67 



This difference in the base from which interpretations must 

 start, in the long run, may make small odds in the true inwardness 

 of fertilization theory. I am not prepared to discuss the point. 

 I am not even prepared to test the reasonableness of any par- 

 ticular answer pro or con for the conviction has overtaken me 

 that I must practise birth-control in matters theoretical. But 

 for one so minded, the one-body-two-body issue involves the 

 whole matter of procedure. To me it is of great practical 

 importance to determine, if possible, once for all, whether egg- 

 secretions contain two substances or only one. 



In his discussion of the question, Lillie 1 says: 'This . . . 

 does not explain why the sperm-agglutinating and the egg- 

 activating properties of the egg-secretion always go together 

 . . . ; when the egg ceases to produce the sperm-agglutinating 

 substance, it has lost its capacity to be activated. These two 

 properties of the egg-secretion hang together normally; their 

 separation under the conditions of chemical analysis may possibly 

 denote a splitting of a single substance of the normal egg." 



Unfortunately it would take us too far afield to discuss the 

 essential question fully from the chemical side. Suffice it to say 

 that during the last three years I have found other methods of 

 isolation and in every case the agglutinating material and the 

 egg-activating material are recovered as separate fractions. The 

 amboceptor apparently has some pronounced physical weakness 

 which causes it to break apart always at a point between the 

 activating group and the agglutinating group. In fact this 

 cleavage takes place so readily whenever one of the two groups 

 combines with a precipitating agent that I have come to doubt 

 whether the amboceptor can possibly hold together when its 

 spermophile side-chain unites with the sperm-receptors. 



However this may be, there is one bit of evidence which seems 

 to me unassailable. Lillie proved that egg-secretions which 

 have passed through Berkefeld filters do not cause the agglutinat- 

 ing reaction. The agglutinating material in this case, as Miss 

 Sampson found last summer, and as I subsequently substantiated, 

 can be recovered by washing the filter cone in sea-water. What- 

 ever views one may hold regarding the physical-chemistry of 



1 "Problems of Fertilization," University of Chicago. Press, p. 240. 



