62 Veterinary Elements. 



eriug. The small tubes wind a great deal and empty 

 into a cavity known as the sinus, which is a widening 

 out of the ureter. Blood is supplied the kidneys by the 

 renal artery and removed by tke renal veins. If a sec- 

 tion of a kidney is made, two portions together with the 

 cut ends, etc., of vessels and tubes, are seen ; the outer 

 part being known as the cortex, the inner the medulla. 

 The kidneys afford the main road for the throwing out 

 (excretion) of broken down nitrogenous material, the 

 ammonia being evidence as to the character of the waste 

 material. The secretion of urine may be considered as 

 a filtering out of waste products from the blood, water 

 being its main constituent; in addition to the filtration 

 process, the kidney cells have a selective action, and 

 take certain substances from the blood which they change 

 somewhat and later discharge into the ufine. The 

 amount of the urine is inversely as the sweat; more urine is 

 passed in cold weather than in warm weather, due to the 

 greater blood pressure in the kidneys at that time (e. g., 

 winter) . The urine of carnivora (dogs, etc. ) is acid, clear, 

 has more solids and is small in quantity, whereas that 

 of herbivora is turbid, poor in solids, alkaline in reac- 

 tion and great in quantity. When horses are fed hay or 

 straw only the urine is alkaline, when fed oats princi- 

 pally, the urine is small in quantity, turbid, acid and 

 sticky. The urine of cattle and sheep is clear, greenish 

 yellow in color and poorer in solids than that of the 

 horse; that of the pig is clear, yellowish and alkaline. 

 Two tubes originate in the depressions of the kidneys 

 and go to the bladder, one entering on either side; they 

 go through the coats of the bladder oil the slant, thus 



