PLATE VIII.

The alloxanic acid was prepared by adding baryta water to a solution of alloxan. The alloxanate of baryta so formed, was decomposed by sulphuric acid; and the clear solution, filtered from the precipitate of sulphate of baryta, was evaporated and crystallized.

Oxaluric acid was obtained by treating a solution of oxalurate of ammonia with hydrochloric acid. The oxaluric acid was precipitated.

Oxalurate of ammonia was prepared by dissolving parabanic acid in ammonia. Upon heating the solution to the boiling point, oxalurate of ammonia was formed, and crystals were obtained upon evaporation.

The oxalurate of magnesia was prepared by saturating a solution of oxaluric acid with carbonate of magnesia. By evaporating the solution, crystals were readily obtained, which were purified by re-crystallization in water.

Oxalurate of lime was made by dissolving carbonate of lime in a solution of parabanic acid. The crystals were obtained by concentrating the solution.

Uramile. A cold saturated solution of thionurate of ammonia was heated to the boiling point and hydrochloric acid added. The mixture was boiled for a few minutes longer and allowed to cool, when crystals of uramile formed.

PLATE IX.

Hippuric acid is readily prepared from the Urine of a person who has taken a little benzoic acid. About ten grains of the acid may be taken, and the Urine passed during the next few hours, concentrated by evaporation, to the eighth or tenth of its volume and filtered.

PLATE VII.

CREATINE, CH,N,O,+2Aq. CREATININE, C,H,N ̧O2. CHLORIDE OF ZINC AND CREATININE, C,H,N,O2, Zn Cl.

Fig. 1. Compound of chloride of zinc and creatinine, as it is obtained from the Urine.

Fig. 2. Compound of chloride of zinc and creatinine, after re-crystallization in water.

Fig. 3. Crystals of creatine obtained from the chloride of zinc compound. Crystallized from an aqueous solution.

Fig. 4. Crystals of creatinine obtained from the chloride of zinc compound.

PLATE V.

URATE OF MAGNESIA, CN,H,Mg O,+6Aq. URATE OF LIME, CN,H,CaO+2Aq. URIC ACID, C1H ̧Ñ ̧06•

Fig. 1. Urate of magnesia crystallized in tufts.

Fig. 2. Urate of magnesia, showing the separate form of the crystals.

Fig. 3. Urate of lime, crystallized in tufts composed of very long acicular crystals.

Fig. 4. Uric acid, precipitated by the addition of hydrochloric acid to urate of potash.

Fig. 5. Uric acid deposited from Urine.