Abstract
A heavy administration of vitamin K_4 to young or adult rats exerted an inhibitory effect on the growth. Levels of erythrocyte and haemoglobin were markedly lowered and a concentration of blood was observed at the advanced stage of the hypervitaminosis. A decrease of leucocyte number was also observed, but a slight increase was detected at the early stage in infant rats. The changes of leucocyte number were mainly those of neutrophilia leucocyte. Nuclear cell number in the bone-marrow was slightly raised at the early stage and then gradually decreased. Changes of erythroblast were most remarkable. In the rat the vitamin K hypervitaminosis occurred most strongly and the function of blood formation was also markedly lowered. A heavy administration of vitamin B_<12> or folic acid was also carried out. However, the water-soluble vitamins had no effect on blood pictures.
