INFLUENCE OF EXTREME HEAT AND COLD. 



815 



extreme heat upon animals. Provoost and Fahrenheit, working under 

 the direction of Boerhaave, 1 found that a dog and a cat placed in a hot 

 stove (63) died in twenty-eight minutes, whilst a sparrow, under 

 similar conditions, died in seven minutes. Duntze 2 observed that 

 dogs could live in an atmosphere at 42 - 2, but died when the 

 temperature was raised to 45. It was found by Delaroche 3 that 

 cats, rabbits, pigeons, and various insects could remain for one 

 hour in a temperature of 36 without fatal results ; the most marked 

 symptom was the greatly quickened respiration. When the tempera- 

 ture was raised to 45 or 53, the cat and rabbit died within two hours, 

 the pigeon in one hour and twenty minutes, the most marked symptom 

 being convulsions. A frog, under similar conditions, was alive at the 

 end of two hours. The temperature of a rabbit exposed to a heat of 45 

 for one hour and forty minutes rose from 39 7 to 43 '8. Exposure to 

 moist heat quickly raised the temperature of animals, as shown in the 

 following table : 



The effect of dry and moist hot air upon different animals was 

 determined by Bernard 4 in numerous experiments ; some of the results 

 are here given : 



In moist hot air the animals died very quickly ; thus, when the 

 temperature was 80, 60, and 45, the rabbits died in two, three, and 

 ten minutes respectively. Experiments made by immersing the body 

 of the animal in hot water gave similar results. To determine the effect 

 of exposing the body to dry heat without warming the air used for 

 respiration, Bernard made the following comparative experiments upon 

 rabbits of similar size : 



1 "Praelect. Anat.," p. 211 ; "ELhn. de chymie," tome i. pp. 148, 277, 278. 



2 Quoted from Delaroche ( 3 ). 



3 Journ. dephys., Paris, 1806, tome Ixiii. pp. 207, 468 ; 1810, tome Ixxi. p. 289. 



4 Gaz. m6d. de Paris, 1859, tome xiv. p. 462; " Le9ons sur la chaleur animale," 

 1876, p. 349. 



