478 



MARIE A. HINRICHS. 



u.v. 



FIG. 2. Reduction of fertilizing power. Radiation reduces the time required 

 to decrease the fertilizing power in all dilutions. Again, the more dilute suspensions 

 are more susceptible. N normal nonradiated sperm. U.V. radiated sperm. 

 A, B, C represent percentages of eggs in early cleavage stages. A a reduction 

 of from 10 to 50% in the number of eggs which cleaved. B a reduction of from 

 90% in the number of eggs which cleaved. C a reduction of from o to 50 l '/ c in 

 the number of eggs which cleaved. 8-16 represent sperm dilutions, e.g., %*% to 

 ^ 16 %. Ordinates represent the time in minutes elapsed since the beginning of 

 the experiment. Abscissa; represent the degree of sperm dilution. 



