STUDIES OF FERTILIZATION 



573 



TABLE 10 



This experiment was unusually successful; the eggs and sperm were 

 perfect, giving 100 per cent segmentations (4). The blood contained 

 so much inhibitor that only 0.5 per cent of the eggs segmented (1). 

 But its action was entirely neutralized by the addition of the agglutinat- 

 ing substance (3). Fertilization 2 shows that in the presence of such an 

 excess of sperm, the agglutinating substance itself has but little in- 

 hibiting power. 



In a similar experiment of Jul}^ 19, 0.9 per cent sperm suspensions 

 were made in solutions 1 to 6 lielow, and a drop of eggs added to each 

 with results noted in table 11. 



1, 2 and 6 show the inhibiting power of the blood on fertilization 

 even with such enormous excess of sperm; 4 shows neutralization of 

 the inhibiting power by a large quantity of the agglutinating substance 

 although the neutralization was apparently not complete (cf . control) ; 

 5 shows that the agglutinating substance contained in an equal part of 

 800 power sea-water solution was inadequate to neutralize the inhibitor 

 in this sample of blood; a considerable part of the inhibitor must have 

 remained free; it must be present therefore, in high concentration. 



Experiments were then made to test the neutralization of the inhibit- 

 ing power of the Ijlood at various dilutions. 



July 22: Used filtered male blood which permitted only 0.5 per cent 

 fertilization. Part of this was saturated with agglutinating substance 

 bj' addition of 50 per cent by bulk of eggs, and filtered. Fertilizations 

 were then made in a series of sea-water dilutions of each, using a single 

 lot of eggs and of sperm (table 12). • 



