DISEASES OF 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 blood 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 
