In the preceding part, the author reported that the alimentary canal was the most favorable and the most certain site for the establishment of infection as compared with others. In the present part, the author studied the course of infection from the administration of virus to its fixation in the liver, paying special attention to that in the stomach and intestine. Mice were used as the test animal. The results were as follows: 1) Some of the virus injected into the stomach were inactivated as the time elapsed, but the rest, not inactivated in the stomach, descended to the intestine. It was possible to recover the injected virus from the stomach. The further the environmental pH went to the acid side, the severer the virus was inactivated. 2) In about 3 to 15 hours after the injection, the virus was clearly proved in the wall of duodenum, jejunum, ileum and colon, through which the invasion of the virus seemed to be carried out.