Abstract
Measurements of internal body temperatures have been obtained in unanesthetized animals after previous implantation of fine thermocouples upon the part to be tested. Prolonged investigation may be carried out with a minimal introduction of error if the animals are permitted 48 hours to recover from the effects of visceral exposure and operative anesthesia which are incident to application of any thermometric device. Seven abdominal organs have been studied in various animals during normal conditions, physiological changes (i. e., uterine temperature during oestrual rhythms), hypothermia, and hyperthermia. The details of thermocouple implantation, instruments and results will be described in a later paper.
Physiological Changes in the Uterus. Concomitant measurements of uterine and body (colonic) temperatures revealed that the uterus conformed to the level of body heat during all stages of the oestral cycle in the rat. Two-hour tests made daily previous to mating, throughout gestation, and for 18 days postpartum showed that the pronounced organic changes occurring in pregnancy and the subsequent states of lactation and involution also failed to give differential organic temperatures. Even the severe muscular contractions present during parturition did not disturb the agreement of organic and body temperatures, although measurements were taken of one rat during delivery of a remarkably large litter of 17 young. Neither the injection of theelin in doses large enough to cause marked uterine growth nor ovariectomy with subsequent castration atrophy affected the uniformity of temperatures. Epinephrine and pituitary extracts were used to produce rapid responses, but no change in uterine temperature was observed save when the body temperature exhibited a like and concomitant change.
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