EFFECTS OF HEAT ON ANIMALS. 143 



Jiving bodies has attracted the attention of physiologists in 

 all ages, who have invented a thousand hypotheses, more 

 or less probable, to account for it. 



It has not been the same with the faculty enjoyed by ani- and also heat, 

 mals, and perhaps by plants likewise, of resisting heat, 

 and preserving a temperature inferior to that of the circum- 

 ambient medium. Scarcely any researches on this head were 

 made previous to the eighteenth century, when the inven- 

 tion of thermometers had enabled the philosopher to mea- 

 sure the heat of bodies with accuracy. The first experi- 

 ments that were attempted might have led us to doubt the 

 existence of such a faculty. Fahrenheit and Provoost, at First experi- 

 thc suggestion of Boerhaave, exposed three animals in ajw cat am j 

 sugar baker's oven, the temperature of which was 146° F. sparrow, killed 

 One of these animals was a dog weighing lOlbs. one a cat, ^g^ 

 and the third a sparrow. All these died, the cat at the ex- in 7 r 28 mi- 

 piration of seven minutes, the other two in twenty-eight. nutes - 

 These experiments were undertaken to verify a theory of Boerhaave's 

 Boerhaave's respecting the use of respiration. He had sup- theory of respi- 

 posed, that it served, by the access of fresh air, to cool the 

 lungs ; in which, according to him, the blood underwent a 

 fermentation, that produced a very considerable degree of 

 heat. From the result of this experiment he thought him- 

 self authorized to conclude, that his theory was well found- 

 ed, and that no animal could live exposed to a heat higher 

 than its own temperature. 



The opinion of Boerhaave seems to have been generally 

 adopted for a certain time by physiologists. It does not ap- Temperature of 

 pear, that any precise notions of the temperature of hot hot climates - 

 climates were entertained at that time; but afterward more 

 accurate ideas of it were formed, which did not agree with 

 the law established by Boerhaave. In 1748, Dr. John Li- 

 nings of Charlestown, giving an account of the meterolo- 

 gical observations he had made in that place, noted the high 

 temperature observed there in summer. Fahrenheit's ther- At Charlestown 



mometer in the shade frequently rose to 85° or 90° : and 85 °> 9o«, and 



98° 

 once he saw it as high as 98°. Though he did not examine i n tne sun 



the temperature of places exposed to the sun, he estimated 124 *« 



with much probability, from other observations made in 



lower temperatures, that it must have been 124°. Adan- 



son, 



