AND HIS DISEASES. 105 



and occasionally various matters taken into the stomach, as 

 food, salts, colouring matters^ and the like," (Kirkes.) In 

 certain states of the constitution, and various stages of 

 disease, the relative quantity of these constituents is greatly 

 increased and apt to be precipitatedj sometimes forming 

 granular deposits in the urine when passed, at others assum- 

 ing the form of gravelly accretions, or even calculous forma- 

 tions in the kidneys, bladder, or urethra, giving rise to much 

 irritation and constitutional disturbance. 



In the horse these accretions are of rare occurrence com- 

 pared with man, owing in a great measure to the more active . 

 habits of the former, and less variety in the articles of his. 

 diet, favouring more active digestion and assimilation, upon 

 derangement of which important processes the disposition to 

 calculous formation depends ; also, the size and relative 

 arrangement of the urinary organs in the horse, favouring 

 the escape •of calculous nuClii before they have attained an 

 injurious size. However, calculi or stones in the bladder are 

 occasionally met with in horses, sometimes in the pelvis of 

 the kidney, but more commonly in the bladder or urethra, — 

 the former being beyond our reach, the latter removable by 

 operation. 



STONE IN THE BLADDER (Vesical Calculi) 



These concretions may be found rolling about in the 

 cavity of the bladder, or surrounded by false membrane 

 adherent to the walls of the viseus (encysted^ or they may 

 occupy the neck passing into the urethra. They are some- 

 times small, and more than one are present, but more gene- 

 rally they are as large as a pigeon's egg or a small hen egg, 

 and single, usually oval or roundish flat in shape, and rough 

 or smooth according to their composition. 



Causes.— They are usually the result of lithic diathesis 



