PLATE 7 



EXPLANATION OF FIGURES 



15 Intense erythropoiesis within developing sinuses. Granulopoiesis out- 

 side the vessels. Two days after stimulation of an 8 day embryo. 



16 The same. Four days after stimulation of an 8 day embryo. 



17, IS and 19 Intense phagocytosis of erythrocytes by reticulum and endoth. 

 cells in figure 17, by a polynuclear macrophage in figure 18 and a lymphoid liemo- 

 cytoblast in figure 19. 



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