This substance, which is found in muscle, is a nitrogenous, very weak base, of bitter taste, having the composition expressed by the formula C4H9N3O2 + H2O. When crystallized from its solution in hot water it forms colourless, oblique, rhombic prisms (fig. 138). Liebig obtained about one ounce of kreatin from 100 lbs. of horse-flesh, and it can easily be obtained from "Liebig's extract of meat". The appearance presented by the crystals is here given.


Fig. 138.-Kreatin.


Fig. 139. - Kreatinine.

Kreatinine is a strong base having the same composition as kreatin, less one equivalent of water, and its formula is consequently C4H7NO3. It is constantly present in the urine, and the crystals present the forms here shown.