AND COLD BATH. 717 



nishes the power of the heart, the circulation of 

 blood through the lungs, and therefore the process 

 of respiration, on which all the other functions of 

 the animal economy depend, for the same rea- 

 son that all the movements of the atmosphere, 

 evaporation and rain, the operations of chemistry, 

 geology, and the growth of plants, depend on the 

 heating influence of the sun. 



Some experiments of Dr. Edwards clearly 

 prove that, like mammalia, birds obtain more ca- 

 loric by respiration during winter than summer. 

 For he found, that when five adult sparrows 

 were placed in a vessel through which there was 

 a free circulation of air, (with a solution of pure 

 potass to absorb the carbonic acid exhaled,) they 

 lost only '72 of temperature in one hour, in the 

 month of February, when the air was at 32. But 

 when the same species of birds were placed in 

 air reduced to 32 in summer, by means of a freez- 

 ing mixture, they lost from 6*5 to 10*8 in one 

 hour, and 2T6 in three hours.* 



* Yet he maintains, in a recent article on Animal Heat, contained 

 in the Cyclopedia of Anatomy and Physiology, that respiration 

 is augmented by the high temperature of tropical climates, and 

 the heat of the body increased until the condition becomes patho- 

 logical, as in fever. (Vol. ii. p. 679.) He adds in another place, 

 that as the proportion of red globules in the blood, exerts an impor- 

 tant influence on the generation of heat, that of fever may be 

 reduced by bleeding and low diet. Dr. C. Holland also maintains 

 that the effect of a high temperature is to produce a more oxy- 

 genated state of the sanguineous fluid, which he thinks predis- 



