The Human Red Blood Cell*

Abstract

The erythrocyte is probably the most important single cell in the animal body. It is a container for hemoglobin by which alone sufficient oxygen necessary for the life of all tissue is transported. Biologically, it is one of the most interesting of all cells. The mature erythrocyte functions as a single unit separate from all other cells; it has no nucleus during its active physiologic life; as it utilizes no oxygen, it has no metabolism of its own; it is always in motion. The red cell may be considered as an inanimate body constantly traveling from lungs to tissues and back again. It is different from every other cell.

Besides its great physiologic interest and importance, the red blood cell is remarkable because it was the first cell seen by the human eye. The first cells of any kind to be described and illustrated were those of the cork in Robert Hooke’s famous “Micrographia” published in 1665.¹ Before this time, however, Swammerdam observed erythrocytes in the blood of the frog and the louse.² He wrote: “The same has been likewise discovered in human blood for several years, it is found to consist of ruddy globules swimming in a clear liquor.” The exact date of Swammerdam’s discovery is unknown but probably was as early as 1658. Malpighi³ in 1665 mistook red blood cells for fat cells in the omentum of the hedge-hog. He described them as “fat cells looking like a rosary of red coral.” Leeuwenhoek was the third of the. . .