[camerox-brownlee] low temperatures ON THE FROG 

 Time Temp rature 



119 



At this point the external temperature was changed. 



Time 



Temperature 

 Ringer External 



-10°C. -5°C. 



At this stage the frog was removed to room temperature in its containing vessel. 



At 8 p.m. there was no sign of life. The heart was exposed, and foimd to be 

 still. The gastrocnemius did not respond to stimulation. It is therefore evident 

 not only that the frog freezes in a manner analogous to that of an isotonic solution, 

 but that prolonged freezing to a minimal temperature of — 2-75°C. kills both 

 frog and the heart tissue. (The gastrocnemius muscle, under the conditions of the 

 experiment, had probably reached a distinctly lower temperature.) 



D. Experiments on the normal intact frog. 



A series of initial rough experiments were carried out. In these the frogs were 

 enclosed in a small jar, which was immersed in a freezing mixture. The internal 

 temperature of the frog was measured by the insertion of the bulb of a small ther- 

 mometer into the stomach through the gullet. The external temperature was usually 

 much below this, so that probably, after the temperature had fallen below the 

 freezing-point of the body fluid, the body-temperature exliibited a marked gradient 

 from the exterior inwards. 



