7S6 Diseases of the Genital Organs 



measure upon the comparative development of the given 

 structure. That is, the seminal vesicles, prostate and Cow- 

 per's glands will tend to become involved in proportion to 

 the functional importance of each in the species under con- 

 sideration. Thus in the bull the seminal vesicle is the most 

 commonly involved subsidiary sex gland, while in the dog 

 the prostate gland suffers most frequently and severely. 



FlG. 22S— Enlarged Seminal Vesicles. Gelding. 

 (J, Urinary bladder; S, S, seminal vesicles. 



Since ascending invasions along the urethro-vas deferens 

 canal naturally tend to become deflected into the subsidiary 

 sex glands, infections of these structures sometimes occur 

 without involvement of the testicles or epididymes. Infec- 

 tions of the subsidiary glands probably as a rule have a 

 greater peril for genital health than infections of the epidid- 

 ymis or testicle, because when the latter are involved the 

 very small caliber of the tubules leads to early atresia with 

 incarceration of the infection, while the structure of the 

 subsidiary glands is such that infected secretions may read- 

 ily escape into the urethra and be ejaculated with the semen. 



