A bluish black, amorphous substance containing iron and obtained from blood. It exists the red blood corpuscles united with globulin, and the form of hemoglobin or oxyhemoglobin gives to the blood its red color.

A brown or blue-black amorphous iron substance that unites with globin and forms hemoglobin.

An iron protoporphyrin differing from heme in that the central iron atom is in the ferric (Fe+++) rather than the ferrous (Fe++) state; the prosthetic group of methemoglobin.

Hematoxylin.