364 Diseases of the Genital Organs 



tween the neck and connecting piece. It appears then that 

 the head, which has up to now faced the center of the cell, 

 becomes reversed and faces the cell wall. From the neck 

 granules, which migrate toward the center of the cell, are 

 formed the centrasomes, or polar bodies, which play such an 

 important part in the mitotic process. 



It is quite clear that an arrest in the development of the 

 centrosmic precursor may be a potent cause of sterility. 

 Judging from some stained preparations on hand, it appears 

 quite certain that this arrest in development occurs to a 

 greater or less degree. 



The body, cylindrical in form, about one and one-third 

 times the length of the head, takes readily either acid or 

 basic stain, and reveals in the properly stained preparation 

 a spiral filament encircling its entire length. The body is 

 succeeded by the tail, of slightly smaller diameter and about 

 four times as long. The tail, tapering posteriorly, ends as a 

 very fine filament. As the body and tail function only in a 

 locomotive capacity, I shall not deal further with them, but 

 shall study the pathologic changes in the heads of various 

 samples of spermatozoa, and the accompanying gross anato- 

 mical and functional changes in the genital apparatus of the 

 bull. 



Bull U, Figs. 113, 114. Eleven years old. For three years 

 was used as sire in a herd of about one hundred mature fe- 

 males. Served sixty-three cows, with two hundred and 

 fifty-one copulations, seventy-five (29.8 per cent.) of which 

 resulted in conception. In 1916, ten cows were served, of 

 which twenty per cent, failed to conceive and twenty-five 

 per cent, of those conceiving aborted. In 1917, thirty-six 

 cows were bred, of which 11.1 per cent, failed to conceive 

 and 21.95 per cent, of those conceiving aborted. In 1918, 

 forty cows were bred, of which 35.6 per cent, failed to con- 

 ceive and 27 per cent, of those conceiving aborted. In 1919, 

 thirty-eight cows were bred, of which 79 per cent, failed to 

 conceive and 40 per cent, of those conceiving aborted. 



After about three or four months in the herd, the bull's 

 fertility became lessened. Since May 1, 1919, he has been 



