Although considerable emphasis in this research was laid upon the reaction of the pulse-rate to muscular activity, which was studied both in the Nutrition Laboratory and by Professor Johnson in Springfield, unfortunately our temperature measurements were not made for the purpose of determining the reaction of the temperature regulating function to muscular work. Pea was captain of the crosscountry team, and on several occasions ran a strenuous race. On November 28 he ran a race of 6 3/4 miles according to the pedometer record. It was impracticable to measure his rectal body temperature under these conditions, but the mouth temperatures are perhaps not without some interest. At 9h30m a. m. after breakfast, when he was lying down, the mouth temperature was 98.6° F. After a run of 54 minutes of approximately 7 miles, and while the subject was lying on the bed, the mouth temperature at llh18m a. m. was 97.4° F. The fact that this subject had been running a race in the open air, with probably more or less mouth breathing, makes these records of relatively little value. The difficulties in obtaining accurate records of the mouth temperature, especially after long races, have been carefully pointed out by Dr. Blake in his observations on Marathon runners.1 It is more than probable, however, that there was no true increase in temperature as a result of this activity, for this fall of 1.2° F. is not unlike that recorded by Blake and his co-workers in the case of the Marathon runners.