OBSERVATIONS ON THE ORIGIN AND STATUS OF THE SO-CALLED "TRANSITIONAL" WHITE BLOOD CELL

Abstract

Probably the status of no white cell of the blood is so uncertain as that of the so-called transitional cell. The original hypothesis of Ehrlich¹ that this cell was a transition form between the large mononuclear and the polymorphonuclear has long since been discarded, although Sahli² still adheres to the view that it is an intermediate stage between the myelocyte and the polymorphonuclear neutrophil. By many (Ehrlich,³ Emerson, Webster and Simon, in the latest editions of their text-books) it is believed to be a senile form of the large mononuclear. Pappenheim and Naegeli refute the hypothesis that this cell is a transitional form between the large mononuclear and the true polymorphonuclear neutrophil, the former regarding it as a promyelocyte in his scheme of blood-cell origin, while Naegeli, after first describing it as related to the myeloblast⁴ concludes that, together with the other mononuclears,