PLATE XII. OXALURATE OF LIME-DUMB-BELLS. The dumb-bell crystals of oxalate (oxalurate) of lime are not precipitated after the Urine has left the bladder, nor do they appear to increase in size by standing. Their presence in the casts (fig. 1.) renders it probable that they are formed in the uriniferous tubes, and this is placed beyond all doubt by the circumstance of their presence in the kidney itself. I have seen small collections of them, apparently impacted in a tube, several times in examining the kidney. Dr. Golding Bird considered that these crystals were composed of oxalurate and not oxalate of lime. The dumbbells polarize the light while the octohedra do not possess this power. The chemical composition of the two forms ist certainly different, for the octohedra are not acted upon by acetic acid, while the dumb-bells are affected by it. The crystalline material is gradually dissolved away by the prolonged action of the acid, until at last nothing remains but the organic matter which corresponds to the original form of the crystal. It closely resembles a cell-wall, but it is probable that this appearance is fallacious. After the action of acetic acid the crystal no longer possesses the power of polarizing the light. The gradual action of the acid is represented in Plate XI, w, v, u, t, fig. 2. Dumb-bell crystals are, in many cases, only present for a few days at a time, which circumstance has probably led to the opinion of this being a very rare form of crystal. The perfect dumb-bell is often preceded by the presence of irregular forms of the same character of crystal, and the circular and oval crystals (from a to m) are often found some days before perfect dumb-bells make their appearance, and after the disappearance of the latter, similar irregular forms are often observed. PLATE XII. OXALATE OF LIME, OCTOHEDRA-OXALURATE OF LIME, DUMB-BELL CRYSTALS IN CASTS. Fig. 1. Dumb-bell crystals in casts from the Urine of a case of cholera. The specimen containing these casts was the first portion passed after eighteen hours complete suppression. It contained a trace of albumen. Octohedra were present in the surrounding fluid, but none could be found in the casts.* * Fig. 2. Octohedra of oxalate and dumb-bell crystals of oxalate of lime with a few cells of bladder epethelium. On the left side of the figure are represented a number of minute octohedra of oxalate of lime, crystallized round a hair. These crystals are often so minute as to appear like mere granules, but their insolubility in potash and acetic acid distinguishes them from other substances which they resemble. Fig. 3. Very symmetrical dumb-bells. * This drawing was published in the Medical Times and Gazette for April 5, 1851. |