Having studied, as mentioned in the previous report, the changes of blood-platelets in the splenic arteries and veins, I extended my investigation into white corpuscles, hemoglobin and reticulated red cells: and with the object of ascertainning what their changes mean, I carried out an histological research of the spleen, the liver and the bonemarrow in the above-stated procedures and came to the following conclusions. 1) In the case of a normal rabbit, the number of the white corpuscles especially the lymphocytes in the splenic veins exceeds that in the splenic arteries. 2) After thyroidectomy and the injection of phenylhydrazin the white corpuscles in splenic veins increase more remarkably than those in splenic arteries, the lymphocytes and monocytes also showing a remarkable augmentation. 3) When adrenalin or silver-elecroid is injected, the white corpuscles in splenic veins outnumber exceedingly those in splenic arteries. When adrenalin is injected, the lymphocytes and monocytes increase especially. When silver-elecroid is injected, the augmentation of the lymphocytes is not comparatively remarkable, while on the other hand, the pseudoeosinophile-leucocytes increase. 4) In the case of a normal rabbit, as well as in that where the thyroidectomy is performed, a greater quantity of hemoglobin is found in the splenic veins than in the splenic arteries, and it is especially so when phenylhydrazin is injected. But the continuous injection of silver-elecroid does not cause any remarkable change of the contents of splenic veins and arteries. The quantity of the hemoglobin fluctuates almost in the same way as the number of the red blood corpuscles does. 5) No remarkable change of the reticulated red cells occurs in splenic arteries and veins. 6) After thyroidectomy and the injection of phenylhydrazin, the appearance of the megacaryocytes in the spleen is demonstrable, but no remarkable change occurs in the liver. 7) Thyroidectomy gives rise to the atrophy of the bone-marrow, the proliferation of adipose tissue and the decrease of megacaryocytes. A similar tendency is recognizable when phenylhydrazin is injected. 8) From these above-stated blood pictures of the splenic arteries and veins, as well as the histological researches of the blood-making organs, it may be inferred that from thyroidectomical causes, the spleen regains, in a compensatory sense, its blood-making function outside the bone-marrow.