Studies on blood cells of the silkworms, Bombyx mori I.

Light microscopic studies.

Abstract

Blood cells of the silkworm, Bombyx mori, were samplied sucessively from the beginning of the third instar to the pupal stadium, and were oberved by a light microscope. The blood cells were classified to five kinds; proleucocytes, plasmatocytes, granular cells, spherule cells and oenocytoides, and their structural properties were described. Further, it was suggested that the granular cells are derived from the proleucocytes. The cell count ( or the number of cells in 1 mma ) of the silkworm showed a cyclic change; minimum or decreasing in the beginning of each instar, then increase rapidly, arriving at a maximum number during molting period (or, in the fifth instar, two days after the ripening). The granular cells and proleucocytes were the main components of the blood cells. In the early stage of each instar, the plasma cells were numerous, which, however, decreased gradually and in the molting stadium compensatory increase of the granular cells was observed.