Abstract
Analyses of the temperature fluctuations within comparatively short observation hours, based on 3998 readings in five different periods on diurnal temperature curves in 785 normal rabbits, were carried out with special, reference to the influence of environmental temperature, natural or air-conditioned, and feeding. Exposed to the external temperature ranging from 4° to 31°C, the average fluctuation of 705 rabbits was less than 0.2°C for any of three two-hour-periods, less than 0.3 °Cfor the four hours consisting of the later two of these three periods and and 0.35°C for the whole six hours. The range of fluctuation, when expressed in group averages, varied depending on the thermal surroundings, indicating a higher internal stability at the optimum temperature of environment. A fluctuation in the first two-hour-period was demonstrated to have a certain. correlation with that in the next four-hour-period. A single measurement of body temperature at the end of the first period may serve as a fail ly reliable index for a possible fluctuation during any length of period. Feeding on the day of observation was found to play an important part in elevating the body temperature and in enhancing its fluctuation. This disturbance was noticeable at any thermal environment and most easily evokable at temperatures higher than 25°C. Changes both in temperature and in its fluctuation pattern developing immediately after placing the rabbit in a constantly air-conditioned room, subsided very slowly and settled on a level corresponding to an internal stability proper to the renewed surrounding, which did not occur, however, until after a lapse of more than four days.
