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Semen : The semen, made up as it is of mixed products of 

 the testes and accessory sexual glands, is very often abnormal, as 

 would be expected in view of the frequency with which changes 

 occur in the glands contributing to its formation. The normal 

 semen is remarkably adapted to its function of nourishment and 

 stimulation of the sjiermatozoa, and their conveyance to the in- 

 ternal female genital organs. The spermatozoa are extremely 

 sensitive to changes in their environment, with the result that any 

 alteration of the physical or biochemical content of the seminal 

 fluid may cause death of the sperms. With this in view, we must 

 remember that disease of any of the contributing organs is a poten- 

 tial danger, and threatens the potency of the animal. Each or all 

 of the glands may add bacteria, acid secretions, or inflammatory 

 exudates. On the other hand, they may not function at all. In 

 each case, however, the semen is altered. 



Unfortunately it is impossible with present methods to obtain 

 the fluid absolutely free from vaginal mucus, but with care it may 

 be secured reasonably free from contamination by douching the 

 prepuce of the bull and vagina of the cow before service. This 

 method was used as often as possible in collecting the samples. 

 The usual amount of semen obtained was from six to ten cubic 

 centimeters. 



With a hj'persecretion of one or all of the glands, the semen 

 becomes quite thin and watery, with a deficiency of solid matter, 

 together wdth changes in reaction. On the other hand, hypofunc- 

 tion results in a secretion too viscid, which is equally unsuited to 

 the requirements of the spermatozoa. The thin watery semen 

 clots imperfectly or not at all, and clotting is essential in protect- 

 ing the spermatozoa from the acid secretions of the vagina. 

 Likewise, a medium too viscid is a distinct hindrance to motility. 

 Changes in reaction are very frequently encountered. The sperms 

 are very sensitive to dilute acids, so that with even a slight acidity 

 motility may diminish or entirely cease. Purulent inflammatory 

 exudates are occa.sionally mixed with the semen, and although the 

 pus cells themselves have not been found to be destructive to the 

 sperms, certain degeneration products in the exudate are very 

 toxic, and inhibit or destroy the motility. So far, I have failed 

 to find red corpuscles present. One very interesting sample of 

 semen was quite thick, of a yellowish green color, and of a dis- 

 tinctly acid reaction. The secretion from the vesicles was later 

 found to be of this same character, and was due to a Ps. pxjocija- 

 neus infection. The vesicles were highly inflamed and degenerated. 

 The spermatozoa were in this case markedly decreased in number, 

 and devoid of motility. 



The early precipitation of the "Boettcherchen." crystals S€ems 

 to be intimately connected with sterile semen, or spermatozoa of 

 lowered vitality. Likewise, a decrease in solid matter is often seen 

 in a deficient secretion. In normal semen, the clot disappears after 

 standing a time, and a thick .sediment settles out. This sediment is 

 decreased in amount as a rule in abnormal semen. 



