A number of experimental observations on the effect of environmental temperature on shock have recently been made.1 It was observed that extremes of heat and cold have deleterious effects on the survival time of animals in shock.1a,b There have been wide differences of opinion as to the optimal environmental temperatures for shocked persons. Thus, Elman and his co-workers1c recommended a temperature of 75 F., Cleghornld 72 F. and Wakim and Gatchle 85 F. Examination of the data presented by the various authors shows that these variations may be due to study of an insufficient number of temperatures in the region of 65 to 95 F. Likewise, the number of animals employed may not always have been adequate for demonstrating significant responses with small differences in temperature.2 It is the purpose of this report to determine in a more complete manner the optimal temperature for