THE CHARACTER OF URINE CONTAINING CYSTINE.
The urine of a cystinuric patient is usually murky when passed, and is faintly acid or neutral. It has a yellow-green color, "honey yellow," and is said to exhale an odor, when fresh, resembling sweet briar or sweet orris root, but it rapidly fouls from decomposition, and sulphuretted hydrogen is evolved, a greasy-looking scum form ing on the surface. The carbonate of ammonia formed by the de composition of the urea throws down a bulky deposit of cystine. Golding Bird noticed that the urine changes in decomposition from yellow to green, and in one case which he records it turned to a bright apple-green. It is stated by Niemann that urine containing cystine is deficient in uric acid, and Golding Bird asserts that urea is only present in very small quantities.
hexagonal plate-like crystals are characteristic, and the surest test for cystine is recrystallization after the crystals have been dissolved in ammonia. The precipitate from cystinuric urine dissolves in potassic hydrate, and if a solution of acetate of lead be added and the mixture boiled, the black precipitate of lead sulphate will result (Liebig). • But all sulphuretted animal matters similarly treated yield black precipitates; hence this test is useless if any portion of albuminous substances or bile be mixed, with the deposit (Bird).
Roberts says that the ammoniacal solution of cystine generally deposits hexagonal plates or these mixed with a few prisms (vide Fig. 67). "Sometimes, how ever, the prisms are more abundant than the plates.
The prisms either lie singly or form stars. They re fract light strongly, and the facets which lie slant ingly out of the direct line of vision appear perfectly black, contrasting with the brilliant lustrous white of the planes through which the light passes vertically.
This gives a peculiar striped appearance to the prisms, and causes them to appear deceptively six sided. The hexagonal tab lets have an iridescent mother-of-pearl lustre, their surfaces being often beautifully chased by lines of secondary crystallization; they also form thick rosettes of great brilliancy." Galculous Formation. —Cystine calculi, which cannot be said to possess any characteristic size or shape, are probably formed in the kidney pelvis, and descend into the bladder. They are usually smooth on the surface. They crush or break without crispness, and feel waxy in the grasp of the lithotrite, proving soft and compres sible, and the fragments are evacuated by suction often with difficulty. The fractured surface is crystalline in appearance and of lemon yellow color. The calculi are usually without lamination. Phos phates may form the coating of the calculus and uric acid the nucleus. When slightly burnt in a candle flame or rubbed on a handkerchief they emit an odor of garlic.
When the calculi are fresh their color is of a pale yellowish brown; they undergo, however, a remarkable change in course of time, turning slowly from brown to gray or green. Thus the calculus described by Dr. Marcet in 1817 was brown; now it exhibits a rich bluish-green color. This alteration is considered by some to be due to the changes produced by the sulphur. A similar change of color has been observed by Dr. Peter in two cystine calculi preserved in the Transylvania medical museum; the change commenced on that side of the concretion which was exposed to the light.