832 INFLUENCE OF COLD ON THE RESPIRATION 



in the air, but died in from eight to twelve hours 

 when immersed in water at the same tempera- 

 ture. He therefore concluded, that air exerts a 

 vivifying influence on the blood and nervous 

 system, independent of the lungs and general cir- 

 culation. But he seems to have overlooked the 

 fact, that owing to the greater conducting power 

 of water, it abstracts the vital heat from animals 

 more rapidly than air. From all the foregoing 

 facts and observations, it is obvious, that the 

 duration of life in animals after respiration has 

 ceased, is inversely as the quantity of their life, and 

 the general activity of their functions. 



In the first chapter of this book, it was shown 

 that in birds and all the more active mammalia, 

 respiration is augmented by cold. But we shall 

 find that among insects, reptiles, and even the 

 lower orders of warm blooded animals, it is dimi- 

 nished by a low temperature ; and that whenever 

 it falls below 52, or the point at which the growth 

 of plants is arrested, all the functions of life 

 become languid, or entirely suspended. For ex- 

 ample, it was found by Spallanzani, that bees 

 and other insects consume three times more oxy- 

 gen at 70 than at 36 ; and similar results were 

 obtained by Treviranus. Owing to the large 

 extent of radiating surface, compared with the 

 actual size of the body, whenever the surrounding 

 air becomes cold, as on the approach of winter, 

 they lose caloric more rapidly than it is gained by 



