HISTOGENESIS OF BLOOD IN BUFO HALOPHILTJS 229 



3. The primitive erythroblasts soon assume the definitive form 

 and acquire hemoglobin. 



4. After this no heteroplastic formation of erythrocytes occurs, 

 up to the latest stages studied. Homoplastic erythropoiesis 

 continues. 



5. Large lymphocytes may arise from endocardial and general 

 endothelial cells. 



6. Mesenchyme cells all over the body may develop into large 

 lymphocytes or lymphoid wander-cells. 



7. The large lymphocyte is the mother cell of all the other 

 white blood-cells. 



8. Three types of granular leucocytes occur: eosinophils, special 

 cells, and mast cells. 



9. The granules of the eosinophil cells are endogenous. 



10. The special leucocytes of Bufo halophilus contain many fine 

 granules, which are not azurophil, but neutrophil. 



The histogenetic relations here described may be expressed 

 by the following diagram, which is self-explanatory in the light 

 of the foregoing account. 



Primitive erythrocyte 



I I 



Small lymphocyte Eosinophil cell 



1 

 Mast cell Special cell 



Eosinophil endothelium cell 



