CALCULUS OF THE KIDNEY.
The hemorrhage from a renal calculus does not possess any marked characteristic beyond the fact that it is affected by sudden movement and severe exercise. That which is evoked by a calculus imbedded in the parenchyma of the gland may have occurred once only in the course of many years, and the circumstance have been for gotten—the chief feature of the case being a fixed renal pain. But the fallacy of basing a diagnosis of cortical or imbedded stone on the one symptom of fixed pain in the kidney region must be avoided. I have known localized renal pain with healthy urine to be due to congestion of the liver (post-mortem case), shrinkage of the kidney (operative case), and colonic ulceration. The bleeding which is produced by a stone in the pelvis or in some deep calyx is the salient feature of the disease and varies in character and amount according to the size and surface of the calculus, its position, the range of its mobility, and the health of the mucous membrane around it.
As a general rule, the bleeding in pelvic calculus is often repeated, dependent on or distinctly increased by exertion. It is rarely pro fuse, the color is never very bright, and the blood is always in timately mixed with the urine. .
Prout," who was an excellent and trustworthy observer, says : " In plethoric and gouty subjects who suffer from uric-acid renal concre tions, the blood often appears in the urine under the form of a dark coffee-colored sediment mixed with uric-acid gravel. This subsides after a time, leaving the superjacent urine apparently little colored.
This hemorrhage is sometimes produced by very slight causes, as, for instance, by an active cathartic which has been taken to relieve a bilious attack. Occasionally the blood is more abundant. Perhaps on the whole renal concretions of oxalate of lime are more apt to pro duce hemorrhage than any other variety. Renal concretions com posed of the phosphates are sometimes accompanied by bloody urine, but if I were to speak from my own experience I should say much less frequently than some other forms of concretions." These remarks are, I believe, mainly correct, but nephrolithot omy has taught us how frequently "imbedded" calculi of oxalate of lime exist without giving rise to hdematuria. As a general rule, the bleeding will be found to occur mostly when the calculi are embraced by mucous membrane and to vary in inverse proportion to the amount of pyelitis. Thus, when pus is passed in the urine in decided quan tities, the hemorrhage is of infrequent occurrence and in small amounts. I may even go further, and state that hematuria due to calculus is rarely seen when a pyonephrotic sac has been formed. It occurs in such case in only thirteen per cent. * The hemorrhage which follows the passage of a small stone along the ureter is transient and its causation obvious. That also which accompanies an attack of renal colic without the passage of a stone is merely due to congestion, and subsides in a day or two.