Urine samples were taken from 35 male adult subjects ecperimentally exposed to high temperatures to measure O/K3, volume, potassium, sodium, chlorine of urine, and the results were studied with their relationship to physical build. 1) Relation to the weight ratio: In the subjects with low weight ratio, a high tendency in O/K3 and low tendencies in Na/K and Na/Cl were seen. (Table 2) 2) Relation to the bust ratio: In the subjects with high bust ratio, a low value in O/K3 and high values in Na/K and Na/Cl were seen. (Table 3) Thus, with the assumption that the O/K3 method is a vitality criterion in man, the above results may be summarized as follows. Subjects who have highly adaptive capacities to high temperature environment are those with high values in bust ratio and those who show relatively higher values in Na/K and Na/Cl.
