The Abdomen 219 



portance from a surgical standpoint because they may, and generally 

 do, exist without inducing symptoms which can be diagnosed. 

 They are often found at necropsies in animals which have suffered 

 from lithiasis exhibited clinically in other parts of the tract. They 

 are usually small, and probably have their origin in the urinifer- 

 ous tubules whence they pass to the pelvis of the organ. Should 

 septic processes take place and induce an alkaline reaction of the 

 urine, very large phosphatic calculi may be formed. The two 

 largest renal calculi recorded were found by Guillon, each occupying 

 one kidney and weighing ninety-six and ninety-seven grams re- 

 spectively. Megnin observed others weighing six and seven grams. 

 Tuffier produced tbem artificially. 



These bodies may cause irritation and abrasion of the walls 

 of the pelvis of the organ, which may lead to more or less hem- 

 orrhage, the blood being carried away with the urine and giving 

 rise to the symptom known as hematuria. If the calculi accumul- 

 ate in large numbers mechanical distension of the organ takes place. 

 But it very often happens that no appreciable symptoms whatever 

 are evident, and it is hardly to be doubted that many urolithic 

 animals go through life without the faintest suspicion of the fact 

 on the part of their owners. It is when the deposits enter the 

 narrower passages and obstruct the flow of urine that they form a 

 serious menace to the animal's existence. If a deposit becomes 

 lodged in any part of the ureteral canal a retention cyst of the kidney 

 or hydronephrosis results. 



Symptoms and Diagnosis. This is very difficult when the 

 kidney is the seat of concretions of dangerous size, and is prac- 

 tically impossible without expulsion of sediment or the smaller 

 calculi. There is usually considerable hyperesthesia of the lumbar 

 region, arching of the back, in some cases strangury, pain at de- 

 fecation, and there may be painful attacks of colic induced by the 

 passage of calculi along the ureteral tract. Lauteur and Guillon 

 have both recorded witnessing attacks of colic. The alkaline or 

 phosphatic calculi are generally preceded by a history of catarrh 

 of the urinary passages. In some cases there is only stiffness in the 

 lumbar region, in others occasional lameness in one or both hind- 

 legs. 



Hematuria may or may not be present, the blood appearing 

 with the last few drops of, or mixed with, the urine, but the amount 



