Note:  Do not rely on this information. It is very old.

Haemin

Haemin, a substance which can be manufactured trom blood. Its importance is due to the fact that it forms characteristic crystals which can be readily recognised under the microscope. If a small portion of dried blood, or of material in which the presence of blood be suspected, be finely powdered with a little common salt, placed on a glass slide, treated with a few drops of glacial acetic acid, and then heated to dryness, microscopic examination will show a number of dark brown rhombic crystals; the formation of these hcemin crystals thus constitutes a very delicate test for the presence of blood.