1. The surface temperature of the right and left ears of 4-month-old Ayrshire bull calves subjected to temperatures of 15, 20, 25, 30, 35 and 40° C. at a low humidity of 17 mg./l. absolute humidity and to 30, 35 and 40° C. at a high humidity of 7 mg./l. saturation deficit, have been measured in a climatic room.
2. From 20 to 40° C. at both humidities, but excluding 40° C. at high humidity, the ear-surface temperatures behaved exactly as did the mean surface temperature of the trunk as expressed in the relation