91 



revival of hard frozen gold fishes, remarks that for a 

 successful demonstration, the animals to be broken before 

 the audience should be left for 35 seconds in liquid air and 

 those to be revived should be withdrawn in less than 

 10 seconds. 



9. Ilomoioihenns. It is well known that the warm- 

 blooded animals cannot support any considerable lowering 

 of their body temperature. Of the abundant literature on 

 this subject, w^e shall select some reports establishing the 

 general fact of the high cold sensitivity of homoiotherms, 

 a few others describing experiments made in some unusual 

 conditions, and still others which are of interest because 

 of the exceptionally low temperature reached. 



Walther (1862), working with rabbits, found that when 

 the animals, immobilized but non-narcotized, were cooled 

 to a body temperature of 18° or 20°, they were unable 

 to recover spontaneously. However, the complete recov- 

 ery of such animals could be effected either by warming 

 them in air at about 40°, or by artificial respiration. 



Coleman and McKendrick (1885) placed a rabbit whose 

 rectal temperature was 37.3°, pulse 160 per minute, and 

 respiratory rate 45 per minute, into a cold chamber at 

 an air temperature of -69.4°, for 2 hours. The animal 

 was then removed for a minute or two; it seemed unaf- 

 fected, though the rectal temperature had dropped to 

 34.5°. Thereupon it was returned to the cold chamber, 

 now at a temperature of -73°, for another hour, after 

 which it was again taken out. The animal seemed to be 

 comatose, reflex action had ceased, there w^ere jerking 

 movements of the limbs, the rectal temperature had 

 reached 6.1°, the pulse rate was 40 per minute, and respi- 

 ration was hardly perceptible. Placed in a warm atmos- 

 phere, the animal recovered completely. 



Colin (1891) reported that rabbits could stay alive in 

 winter after 5 or 6 days at an atmospheric temperature 

 of - 10° to - 15°, in cages hanging on trees. 



Pictet (1893) subjected a dog weighing 8^ kilos to an 

 air temperature of - 90° to - 100° in one of his ref rigera- 



