Light and Electron Microscopic Studies on the Development of Granular Leucocytes in the Chick Spleen and Yolk Sac

Abstract

<p>Imprints and tissue sections of chick yolk sac and spleen from 4 days incubation to 2 days post hatching were studied with the light microscope after staining with May-Griinwald Giemsa stain. A sequence for the development of heterophils was determined from imprints of the spleen, and some stages in eosinophil and basophil development were described. The cells observed in the spleen were compared with those from the yolk sac. The time of appearance and location of granulocytes in both organs is described. Preliminary electron microscopic observations were made on the granulocytes found in the 14 day embryonic spleen, and three types of granules were described. The morphology of yolk sac blood vessels mid way through incubation is discussed.</p>