PLATE 1 



EXPLANATION OF FIGURES 



The three photographs in this plate were taken from the nucleus hypoglossus. 

 The sections from the various animals were mounted on the same slide and hence 

 stained together. X 320. 



1 Before hibernation. Woodchuck killed October 25, 1913, without any 

 anaesthetic. Animal active. Rectal temperature 37.6°C. 



2 During hibernation. Woodchuck killed March 7, 1914, without any anaes- 

 thetic. Animal very dormant and had been so nearly all the time for at least 

 three months. Rectal temperature 9°C. 



3 After hibernation. Woodchuck killed April 11, 1914, without any anaes- 

 thetic. Animal active. Had been fed for two weeks. Rectal temperature 37°C. 



