1. The length, width, thickness, weight and specific gravity of the grains infected by smut through a flower are smaller than those of healthy ones, either in barley or wheat. 2. Luster of the infected matured grains is less and the color is somewhat darker than the healthy ones. 3. When smut spores are put on the stigma of barley or wheat, they soon germinate and then penetrate into its tissue, and the mycelium is found in the embryo at least after 3 days. 4. Smut spores can hardly germinate on other places of a flower, except on the stigma which is rich in mucilage. 5. It is not probable, from my experiments that the smut mycelium can infect through the wall of pistils.