STUDIES OF FERTILIZATION 539 



(,A) 1 cc. 64 agglutinating solution plus 1 cc. (approx.) 3 per cent sperm 



(B) 1 cc. A plus 1 cc. 3 per cent sperm 



(C) 1 cc. B plus 1 cc. 3 per cent sperm 



(D) 1 cc. C plus 1 cc. 3 per cent sperm 



In this case after centrifuging off the sperm, B, C and D were 

 negative; A was faintly positive. That is, 1 cc. of approximately 

 3 per cent sperm fixed 1 cc. of a 64 power agglutinating solution. 

 This shows a greater binding power than in the previous experiment, 

 but easily within the limits of error arising from difficulty of stand- 

 ardizing the sperm suspension, owing to the unavoidable inclusion 

 of some fluid in the sperm. Other tests gave comparable results. 

 Reduced to common terms : 



August 9: 1 cc. 3 per cent sperm fixes 1 cc. 64 power agglutinating solution. 

 August 13: I cc. 3.3 per cent sperm fixes 0.66 cc. 64 power agglutinating solu- 

 tion 



The difference is considerable, but when one considers first the 

 difficulty of obtaining equivalent sperm suspensions and second 

 the 2 to 1 method of standardizing the agglutinating solutions, 

 and third, possible variations in the delicacy of the sperm suspen- 

 sions used as indicators, the results lie well within the limit of 

 error and indicate that there is a definite quantitative relation 

 involved. 



The possibility remains that the disappearance of the aggluti- 

 nating substance in sperm suspensions is a phenomenon of ad- 

 sorption rather than of chemical union. Experiments planned 

 for an adequate test of this possibility were crowded out by other 

 problems. 



If sperm suspensions are allowed to stand for some hours they 

 reach a condition when they will agglutinate only with strong 

 solutions. If the binding power is then tested it is found that 

 they fix as much of the agglutinating substance as before. The 

 fixing power of the sperm is thus entirely independent of its 

 capacity for being agglutinated, which is of course to be expected. 

 But it is important, nevertheless, to emphasize it; the capacity 

 for being agglutinated depends upon the motility of the spermato- 

 zoa, the binding capacity depends merely upon the presence of 



THE JOURXAL OF EXPERIMENTAL ZOOLOGY, VOL. 16, NO. 4 



