THE INTESTINES 25^ 



white, soft in its texture, and highly organised. It 

 possesses numerous follicles or little glands, from 

 whose excretory pores issue a plentiful mucous secre- 

 tion, to defend it from the acrimony of the saline and 

 other matters contained 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 appre- 

 hended 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 dis- 

 orders to which the bladder is liable at page 72. 



THE INTESTINES. 



The intestines are cylindrical tubes of very un- 

 equal dimensions, forming one continued but con- 

 voluted canal from the lower orifice of the stomach to 

 the anus, in which the process of digestion, begun in 



