i8o 



Scientific Proceedings (54). 



morphia per jugular. Infundibulin per jugular had the most 

 powerful action in reducing the volume of the thyroid, although at 

 times there was a preliminary momentary increase. Adrenalin, 

 after a temporary increase, produced a decrement in the volume. 

 An infusion of the fresh ovary of a pregnant cat augmented the 

 size of the thyroid, a fact noted by Hallion. Mammary, corpus 

 luteum, thyroid, placenta, iodine and parathyroid extracts also 

 increased the volume. The anterior part of the pituitary decreased 

 the volume. 



114 (810) 



The relation of external temperature to hibernation. 



By Sutherland Simpson. 



[From the Physiological Laboratory, Medical College, Cornell 

 University, Ithaca, N. Y.] 



In a former communication 1 to this society it was shown that 

 the absence of food is an important factor in determining the 

 onset of hibernation in the woodchuck {Marmotta monax). In the 

 present note attention is drawn to the fact that the cause of the 

 awakening of these animals from their torpid condition in the early 

 spring is not a rise in the temperature of their surroundings. 



A colony of woodchucks was kept in artificial burrows a little 

 over four feet 2 below the surface of the ground, as already de- 

 scribed. 3 At the bottom of one of these burrows, the oil bulb of a 

 Friez thermograph was placed, and connected with the recording 

 clock-drum contained in a box at the top. All the burrows were 

 packed with dry straw, while the one containing the bulb was 

 shut off from the central court, to prevent the woodchucks having 

 access to it. 



A continuous record of the temperature at this depth has been 

 kept from January 1 , 1912, till the present time. It shows that the 

 lowest temperature is reached late in March or early in April — 

 just about the time when the hibernating woodchucks are begin- 

 ning to wake up. There is no appreciable rise in temperature 



•The Food Factor in Hibernation, Proc. Soc. Exper. Biol, and Med., Vol. 

 9 (April 17, 1912), p. 92. 



2 Accurate measurement shows the burrows to be a few inches over four feet 

 below the surface and not five feet as formerly stated. 



1 Loc. cit. 



