The normal body temperature of the pigs used in these experiments showed an appreciably greater variability than has hitherto been considered normal for pigs, the limits being 98·3–104·80° F. and the variation is independent of environmental temperature, or season of the year. The average normal temperature of the adult hog is 101·7° F.In fasting for from two to five days a reduction of body temperature was noted in a large majority of cases, amounting on the average to 1·7° F.Whether the normal or fasting figures are taken, the mean body temperature is higher in youth (50 days) than in the adult hog by about 1·5° F.