Although early light microscopists of the 18th century recognized that blood was composed of red spheres and larger white “corpuscles”, it was not until the development of staining techniques, especially by Paul Ehrlich in the 1880s, that it was possible to determine that these “colourless” corpuscles or white corpuscles were of several types. The cells commonly called polymorphonuclear neutrophil leucocytes, PMNL, PMN, or simply neutrophils were first described by Ehrlich as “polynuclear cells”. 1