282 MANUAL OF MODERN FAKRIERY. 



it from the acrimony of the saline and other matters con- 

 tained in the urine ; this mucous matter being perpetually 

 washed off from the surface of the inner coat by the urine, 

 is kept constantly renewed, and it is sometimes voided in 

 considerable quantities. When this is the case, it may be 

 apprehended that the urine is unusually acrid, or that 

 calculi or other irritable matter is within the bladder. 

 About an inch before the cervix or neck of the bladder, in 

 the sides of the bag, the orifices of the ureters are placed, 

 which enter the bladder in an oblique direction, and prevent 

 any reflux of the urine at the time the bag is contracting, 

 and which gives them the property of valves. The bladder 

 terminates in a small neck, round which is a powerful 

 muscle, which keeps the passage closed and retains the 

 urine until the animal wishes to expel it ; or when the 

 bladder contains a certain quantity of fluid, the muscular 

 coat contracts, and, the lungs being filled with air, the 

 diaphragm is rendered convex towards the intestines, and 

 they are by that means pressed upon the bladder, and by 

 their united powers the fluid is forced through the sphincter 

 muscle at the neck of the bladder and escapes. We have 

 described the disorders to which the bladder is liable at 

 page 93. 



THE INTESTINES. 



The intestines are cylindrical tubes of very unequal 

 dimensions, forming one continued but convoluted canal 

 from the lower orifice of the stomach to the anus, in which 

 the process of digestion, begun in the stomach, is completed 

 and ultimately expelled in the form of faeces. 



The abdominal viscera, taken collectively, cannot be said 

 to occupy any particular region of the belly, for they are 

 spread chiefly over the lower portions of it ; immediately 



