TEMPERATURE CHARACTERISTICS FOR FREQUENCY OF RESPIRATORY MOVEMENTS IN YOUNG MAMMALS

The internal temperature of 2 day old mice deviates by +0.01° to +3.0°C. from the environmental temperature over a range of 24°. The undeveloped temperature control allows rhythmic activities in this mammalian material to be readily subjected to the analysis afforded by temperature characteristics, and thus makes possible some insight into the physicochemical events controlling vital processes in entire uninjured mammals. The thermal increments and critical temperatures obtained point to a similarity in the controlling system of reactions for both homothermic and poikilothermic organisms. For frequency of respiratory movements the increments 12,340 (19.6° to 35.2°C.); 28,340 or 36,500 (15.5° to 19.6°C.) are most frequently found (thirteen cases). Rarely µ = 8,450, 33,000, or 18,340 (two cases). The last increment is either associated with µ = 36,000 below 20°, or extends unbroken throughout the whole range (one case).