DISEASES OP THE HOG. 189 



CHAPTER XXI. 



DISEASES OF THE URINARY ORGANS. 



A short description of the kidneys is necessary 

 so that we may have a better idea of the cause and 

 nature of their diseases. The kidneys are two 

 glandular organs situated in the lumbar region 

 of the back. They are composed of a number of 

 tubes and tufts, around which the bl(Tod vessels 

 run. The supply of blood to the kidneys is very 

 large for the size of these organs. The tubes be- 

 gin very small at the surface of the kidney and are 

 very numerous; they soon join one another, be- 

 coming larger and finally terminate in a part of 

 the kidney termed the pelvis. At the lower border 

 from this place there is a small duct which leads 

 to the bladder, through which the urine passes. 

 The use of the kidneys is to secrete the water and 

 effete matters in the form of urine and uric acid, 

 which would soon poison the body if it remained 

 there. The blood vessels ramify around the tubes, 

 and the epithelium of the tubes secretes the urine 

 from the blood, and if we consider the quantity of 

 urine which is secreted daily we need not wonder 

 at the size of the blood vessels which go to and 

 from the kidneys. If from want of action, from 



