SEASICKNESS is a serious inconvenience to many people in times of peace. In times of war, however, motion sickness in its various forms may be a very real threat to the success of operations in the air and on the sea. Army personnel are apt to be affected in very large numbers, when airborne or in landing craft, since they have little opportunity to become acclimatized, as does the sailor or the airman. The literature on motion sickness up to 1942 has been reviewed elsewhere.1 Since that time a large amount of important work has been done, but publication has been in restricted reports. It is hoped that various workers will soon write up their results for open publication. The present paper is a summary of studies carried out during the recent war by a group of workers in Montreal of which we were a part. These experiments on