48 



is, at the time, of lowered degree of fertility. One should be very 

 cautious, however, in foretelling how long the condition will last, 

 or if the animal may in time be restored to full fertility. Ster- 

 ility, due to' organic disturbances, probably seldom yields to treat- 

 ment, but when it is due to functional disorders resulting from 

 defective diet or lack of exercise, the condition is frequently reme- 

 died by overcoming the cause. Lack of exercise and overfeeding 

 seem to be etiological factors in a fair percentage of cases. 



Besides abnormalities of the male genital tract, we must always 

 consider the numerous factors in the female that may kill or 

 weaken the sperms. Impediments to successful coitus may be 

 present in the form of vaginal constrictions, abnonnally short or 

 small vagina, or other deformities. Hostile exudates, mechanical 

 obstructions, and other factors may interrupt the progress of the 

 sperms at any point in the tract. 



Although little is known definitely regarding disorders of the 

 endocrines in the bull and their relation to reproduction, the w^ork 

 in human medicine and experimental researches upon laboratory 

 animals warrant thoughtful consideration of these factors which 

 are by no means insignificant. In the future, these glands will no 

 doubt receive more and more attention in their relation to the 

 genital organs and reproduction. 



Conclusions 



1. The genital organs of the bull quite frequently undergo 

 pathological changes, due to infection with the same varieties of 

 microorganisms associated with genital infections in the female. 



2. In all probability, these microorganisms are frequently elimi- 

 nated with the semen and infect the female during copulation. 



3. Past or present infection in the genital organs of all the 

 bulls so far examined was evidenced by the presence of the fine 

 connective tissue tufts and strands upon the tunica vaginalis, par- 

 ticularly that part covering the tail of the epididymis. 



4. LoAvered sexual capacity is, as a rule, accompanied by 

 demonstrable changes in the semen. 



5. A study of impotency and sterility includes not only a thor- 

 ough study "of the genital organs, but also those extrinsic factors 

 which govern reproduction either directly or indirectly. 



6. A thorough knowledge of the anatomy and physiology of the 

 male genital organs is fundamental to a clear understanding of 

 the problem. 



I am much imlebtecl to Drs. W. L. and W. W. Williams for some of the 

 material, and for helpful co-operation in the early part of the work; to 

 Drs. C. M. Carpenter and R. R. Birch for many helpful suggestions; and to 

 Dr. J. N. Frost and others who so kindly co-operated by placing at my dis- 

 posal samples of semen and some of the genital tracts. 



