MORBID ANATOMY - CALCULUS OF THE PROSTATE.
Concretions of the first variety are found in the prostate post mortem, in cases in which there have been no symptoms referable to the organ during life. Minute concretions of this kind are some times found in the urine. They are first of microscopic size, and in the majority of cases never attain sufficient dimensions to be of any practical importance. As seen with the microscope, they are small, ovoid bodies of a light yellow tint and pearly lustre. In the large concretions the color is a dark orange. When first formed they are soft, but later on they become petrified and hard. They are precisely similar to the concretions which form in the follicles of the tonsil and which are occasionally coughed up by patients with chronic faucial disease. In elderly patients they may attain the size of a pea or larger, and may be very abundant. Thompson describes a case in which several thousand of these concretions were visible micro scopically. They are found in the secreting follicles and excretory ducts, constituting the parenchyma of the prostate. The earthy material is deposited very slowly, in concentric laminfe, as is the case with phosphatic vesical calculi. The walls of several ducts and folli
cles may be absorbed and form a single cavity within which a num ber of such concretions may be found. When they become larger and the opening of the cavity within which they are contained com municates freely with the prostatic urethra, the salts of the urine are deposited about them, and they become genuine prostatic calculi. Cases have been reported in which the entire prostate was converted by absorption into a sac completely distended with small calculi, which could be felt rolling under the fingers like beans in a bag. Prostatic calculi sometimes fuse together and form a sort of cast of the prostatic ducts and urethra. A length of four or five inches has been said to have been attained. Thompson refers to a case in which there were nine fragments weighing altogether three and one-quarter ounces. Chemically, true prostatic calculi are composed chiefly of calcic phos phate awl a small quantity of ammoniaco-magnesian phosphate. They never give rise to trouble unless they are exceptionally large, in which event they occasion a certain amount of mechanical disturb ance and urinary obstruction.