312 PRINCIPLES OP VETERINARY SCIENCE 



walls or to a spasm of the muscle which guards the opening into 

 the urethra. In the male, strictures in the urethra, an accumula- 

 tion of smegma or salts of urine in the sheath, and other mechan- 

 ical obstructions may close the opening of the penis so as to 

 interfere with the escape of urine. The important symptom is 

 a frequent effort to urinate. If standing, the animal stretches 

 out and violently strains, but either can pass no urine at all or 

 only a few drops. The pain caused by the distention of the blad- 

 der walls is evidenced by groaning. By palpation through the 

 walls of the rectum the greatly distended bladder can be felt. 

 In the mare and cow, pressure upon the bladder causes the urine 

 to flow out in a stream. The bladder of the stallion or gelding 

 can be emptied best by use of the catheter. Where tumors or 

 other mechanical objects press upon the urethra the only perma- 

 nent relief is completely to remove the obstructions. If the 

 sheath is foul from an accumulation of dirt and smegma, it 

 should be carefully washed with warm water and castile soap and 

 then greased with vaselin. 



Nephritis or inflammation of the kidneys is a rare disease in 

 animals. The reason for mentioning it is to emphasize the fact 

 that many times errors are made in diagnosis, and diseases 

 originating or located elsewhere are referred to the kidneys. 

 Soreness in the muscles of the loin from overexertion or exposure 

 to cold is commonly diagnosed as nephritis, because the animal 

 exhibits tenderness when pinched. If the temperature is ele- 

 vated, the urine abnormal in quantity or quality, and the legs 

 swollen, there is a greater certainty that the kidneys are in- 

 flamed. In this event they should be relieved from work by 

 eliminating waste products through the alimentary tract and skin. 



STERILITY 



Sterility is the inability of the male to fertilize the ovum of the 

 female. There are two forms of sterility, viz. : (1) Complete or 

 permanent and (2) incomplete or temporary. The first form 

 exists when the animal is unable to complete the act of copula- 

 tion ; the condition resulting is known as impotency . In the second 

 form the coital act, which includes the ejection of semen, may be 

 completed, but the semen does not contain spermatozoa that are 

 capable of fertilizing the ova; the resulting condition is azo- 

 ospermia. 



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