I 5 



CELL NUMBER, n 

 Fig. 19. Standard deviation a- (n) in the number of cells present in an 

 area 150 microns </> in various semen samples. The line represents the 

 standard deviation for Poisson distribution. 



0.01 



TIME INTERVALS 

 Fig. 20. Distribution of time intervals between passages of sperm cells 

 over the aperture of the photoelectric apparatus. Four experiments. The 

 data for the four ejaculates have been normalized so as to fit them to the 

 same theoretical curve. 



V2 



