In 1854 I submitted to the Royal Society a paper “On the frequent occurrence of Indigo in Human Urine.” This communication, which was published in the ‘Philosophical Transactions,’ attracted considerable attention both at home and abroad. The singular fact of the frequent presence of indigo in the urine, first announced by me, has since been amply confirmed by a variety of observers. I have now to place before the Society some investigations in relation to the not uncommon occurrence in human urine of
phosphate of lime
, as a
deposit
, in a well-marked
crystalline
form. When the earthy phosphates are treated of by writers, in connexion with the urine, they are usually described collectively, and it is seldom that each kind of phosphate is particularized, and yet there are several which may occur either separately or together. The phosphate of ammonia and magnesia, or triple phosphate, is indeed often specified, but rarely is phosphate of lime separately mentioned, and phosphate of magnesia scarcely ever; and yet phosphate of lime is very frequently present as a deposit in urine, much more so, indeed, according to my experience, than the triple phosphate, excluding those cases of the occurrence of that ammoniacal phosphate, arising from the decomposition of the urea of the urine subsequent to its escape from the kidneys. Even in those few cases in which phosphate of lime is specially mentioned, it is described
usually
as mixed up with the other phosphates, and
always
as occurring in the
amorphous
or
granular
, and never in the crystalline state; further, no peculiar importance is attached to it, as contrasted with the magnesian phosphate.
On cystic oxide, a new species of urinary calculus
