The intranuclear origin of the mammalian red blood corpuscles observed in living cultures

Abstract

The present experiments on the origin of the mammalian (cat) red blood cells were the outgrowth of a study to determine the different stages in the development of the normoblast into a true red corpuscle by means of a living culture of red bone marrow. It was early found that the modern explanation of the formation of the mammalian red blood corpuscle did not agree with the activities observed in the cultures and that instead of witnessing a normoblast re-modeled into a non-nucleated corpuscle by losing its nucleus we saw this same normoblast sending out unnucleated straw-colored bladders from its nucleus, these bladders finally separating off as true red corpuscles. This process was not confined to the normoblast type but was evident in the lymphocyte series of white cells. Moreover our observations show that the normoblast in the mammal (cat) and the red corpuscle in the bird (chick) arise from white cells by an intranuclear activity and at the time when they first emerge from the parent cell they are almost indistinguishable from each other.

The principal results are:

I. The mammalian red blood corpuscle is a nuclear bud which escapes into the circulation as the true red cell.

2. The mammalian normoblast and the red corpuscle of the bird are the product of intranuclear activity and are phylogenetically identical.

3. Phagocytosis of red cells by the giant cells (megakaryocytes) in normal blood-forming tissues is by no means common. The true process is undoubtedly the manufacture of red cells and not the destruction of them.