CHAPTER XIV. 



THE URINARY ORGANS AND THEIR DISEASES. 



THE KIDNEYS. 



The blood contains much watery fluid, which, after it has ans.?ered. 

 certain purposes connected with digestion, or the various secretions, 

 is separated and carried out of the frame. The kidneys are the 

 main instruments by which this is effected ; and they are often called 

 into increased action in order to compensate for the deficiencies of 

 other parts. When the usual discharge of perspiration from the 

 skin is suspended, the kidney takes on increased activity ; and when 

 fluids are accumulating in the frame generally, or in particular parts, 

 they escape by means of these organs. Also other substances, the 

 accumulation or the continuance of which in the frame would be 

 injurious, are got rid of by means of the kidneys. The essential 

 principle of the urine (the urea) is one that would be noxious, or 

 perhaps destructive. 



The kidneys are two glandular substances, attached on either 

 side to the spine beneath the muscles of the loins. They are not, 

 however, exactly opposite to each other, but the left kidney is pushed 

 somewhat backward by the great development of the rumen. A 

 very lai-ge artery runs to each. The quantity of blood which that 

 vessel carries shows the importance of the kidneys, and well accounts 

 for the inflammation and other diseases to which they are occasion- 

 ally subject. These arteries divide into innumerable little branches, 

 coiled upon and communicating with each other in a singular manner ; 

 and the blood, traversing all these convolutions, has its watery and 

 noxious ingredients separated in the form of urine, which is carried 

 on to the bladder, while the portion that remains is returned to the 

 circulation by means of the veins, which bear a proportionate size to 

 that of the arteries. 



As the process of digestion is so perfectly performed in cattle, 

 and all the nutritive, and some, perhaps, of the noxious matter which 

 the food contains, taken up and received into the circulation, the 

 kidneys have much to do in order to complete this process of separa- 

 tion ; they are therefore large ; are complicated in their appearance ; 

 they present an assemblage of diff'erent lobes or lobules, separated 

 by deep scissures ; there are ample provisions made for their secu- 



