1. In the case of acute, depleted domestic rabbits, Heinz's body appeared in an intermediate degree 12 hours after the depletion, while in the case of chromic, depleted rabbits a slight or an intermediate acceleration of the Heinz-body formation was noticed 24 hours after the depletion and there on. From this the penetrability through the wall of erythrocytes seems to have an important relationship with the formation of Heinz's body. 2. The formation of Heinz's body is quite high in the case of the rabbits inoculated with phenylhydrazin, thus the penetrability in this case also, raises a question. 3. In the rabbits injected with benzol, the formation of Heinz's body has been of a high degree, and their recovery necessitates an extremely long period of time. 4. In the case of those receiving saponin injection, a mild degree of the formation of Heinz's body started 8 days after the initial injection, but after the cessation of the injection the formation decreased rapidly along with the improvement of hematic picture; and four days after the cessation all returned to normal. 5. In the kollargol injection cases, an intermediate degree of the formation was noticed 8 to 12 days afterwards, and it was found that the reticulo-endothelial system has something to do with the elimination of Heinz's body. 6. With the use of a phase-contrast microscope, Heinz's body in the form of unstained specimens had been possible of observation in each contrast but reticulated erythrocytes could not be observed. This seems to be due to the fact that there is no difference at all in the phase-contrast between the reticulated substances of reticulated erythrocytes and the cytoplasmas of erythrocytes.