Effect of hot-air room treatment on peripheral leucocytes was examined in guinea pigs by observing the numerical changes after the treatment. The results were as follows. 1. Number of totalleucocytes was decreased immediately after hot-air room treatment with a room temperature of 43℃, humidity of 75-87% and rapidly increased from 30 to 120 min after the treatment. Numerical changes of neutrophils showed a same tendency as that of total leucocytes. 2. Lymphocyte count was not changed or
slightly decreased after the hot-air room treatment. 3. Number of basophils was decreased 30 min after the treatment and then increased, differing from that of eosinophils which showed a decreased tendency 120 min after
the treatment. 4. Numbers of monocytes and Kurloff cells were slightly increased after the treatment.