1. Healthy b-classed rabbits fed on tofukara show a decreased blood platelet count on an administration of vitamin B. 2. Healthy b-classed rabbits fed on tofukara show an increased blood platelet count when they begin to be fed on B-avitaminotic food, and as the B-avitaminotic stage is more advanced, the count becomes more remarkable. 3. But when B-avitaminotic feeding is long continued or when animals draw near, or are in, the paralytic stage, the count decreases. 4. When the B-avitamintic feeding is continued for along time, a daily administration of vitamin B in a fairly large amount causes the increased count to become decreased again. This concides with my clinical experience reported in the 60th Report on the Peroxidase Reaction. But a long continued use of the vitamin will not save animals from an ultimate increase of the count and from ensuing death. 5. In this case a combined use of vitamin B and yakriton will make the general state remarkably better, and the count notably smaller, until animals will be quite safe from death.