RKTROCRliSSIVl-; TISSITE Cll A N( ;i-:s. 



235 



in the horse. They usually cause difficulty in micturatinq- and 

 may completely obstruct the urethra with the same results that 

 are produced by occluding the urethral opening of the bladder. 

 Urethral calculi may produce erosions of the urethra and sur- 

 rounding tissues and thus, pnidnce an artificial urinary canal 

 through which the urine will ije discharged, this is probablv 

 more common in male buvines, than in other animals. 

 About 200 urethral calculi were observed in the urethra of one 

 Steer by Dr. B. F. Kaupp. 



6. Preputial calculi sometimes occur in geldings, although these 

 are more freqtientlv accumulations of the secretion from the ad- 

 jacent sebaceous glands. W. Williams reported cases in which 

 there was formation of stalactite bodies in the prepuce of oxen 

 and sheep that had been fed food material containing a large per 

 cent of phosphates. A preputial calculus weighing 11 grams 

 (^/j oz.) and another weighing 10 grams were obtained from a 

 hog bv a veterinary inspector. 



Salvz'ary calculi occur most frequently in the horse, althougli 

 they do occur in the ass, ox and sheep. Their formation depends 

 upon the ingested water containing a large quantity of car- 

 bonates of potassium, sodium and magnesium and the ])resence 

 of calcium salts in the sali\-a. (Dr. J. yi. Lawrence, X'eterinarian 

 U. S. Armv, Fort W'ingate, X. J\I., operated upon two horses, 

 removing from Steno's duct in each a salivary calculus. In 

 the center of one of these calculi an oat grain (nucleus) was 



"'hotograiih ul a Salivary CaLciilus i-umoved from Steno's Duft, hnrsf 



found upon which the deposit had taken place. This calculus 

 weighed 19 grams (-/, oz.) The result of salivary calculi is 

 to oljstruct the outflow of saliva, the retention of which in the 

 smaller ducts may cause inflammatory, degenerative or atrophic 

 changes in the gland, and if the calculi are not removed the des- 

 truct'Ton of the'gland or the rupture of the duct and a salivary 

 fistula. Tartar on dogs' teeth has an origin similar to that of 

 salivary calculi. 



