MEASUREMENT OF SPERM MOTILITY 



37 



15 



E 

 ~ 10 



UJ 

 Q 



D 

 \- 



_l 



1 5 



J I I I I I I I I I 1 I 



50 



100 



200 



VELOCITY (fim/SEC.*) 



Fig. 5. Relation between velocity v of rotating sperm and the ampli- 

 tude b of the tail wave. 



The constant 8 rot can be interpreted as expressing the efficiency of 

 the tail wave in propelling the sperm. The frequency of the tail 

 wave / could not be measured from these films since the frame 

 sequence proved to be too slow for the purpose. Because the tail 

 wave is synchronized with rotation of the cell, the ratio j/f TOt must 

 be an integer; but, as can be seen from Fig. 1, it is not possible to 

 decide whether this ratio is 1, 2, or 3. 



Cells Swimming in Circles 



Successive positions of a cell swimming in a circular orbit are 

 shown in Fig. 6. These cells show no rotation, and the tail wave turns 

 out to be flat, that is, two-dimensional. Within the accuracy of our 

 observation, no "vertical" movement was measured. 



The amplitude of the tail wave of these cells shows a clear asym- 



Fig. 6. Successive positions at intervals of 1/50 sec of a sperm swim- 

 ming in a circle; the orbit is shown at each position. 



