14:2 SCIENCE OF COMMON THINGS. 



Vital heat. Effect of climate on animals. 



who has not sufficient protection, first causes a sensation 

 of pain, and then brings on an almost irresistible sleepi- 

 ness, which if indulged in proves fatal. A great excess 

 of heat also cannot long be sustained by the human 

 system. 



OS Does each species of animal appear to have a peculiar tempera- 

 ture? 



Yes ; each species of animal and vegetable appears 

 to have a temperature natural and peculiar to itself, 

 and from this diversity different races are fitted for 

 different portions of the earth's surface. 



O9 What effect does the peculiarity of temperature have upon the dis- 

 tribution and location of animals and plants upon the earth's surface ? 



The different species are confined and circumscribed 

 within certain districts, depending mainly on their re- 

 lations to heat. Thus, the orange-tree and the bird of 

 Paradise are confined to warm latitudes ; the pine-tree 

 and the Arctic bear, to those which are colder. 



01O What curious fact in relation to a species of whale illustrates the 

 influence of temperature in defining locations ? 



It has been ascertained that at least one species of 

 whale is precluded from migrating from the north to 

 the south, from its inability to live in the heated waters 

 of the equator. 



11 When animals or plants are removed from their peculiar and 

 natural districts to one entirely different, what changes take place f 



They either cease to exist, or change their character 

 in such a way as to adapt themselves to the climate. 



913 What curious illustrations do we find of this f 



The wool of the northern sheep changes in the tropics 

 to a species of hair. The dog of the torrid zone is 

 nearly destitute of hair. Bees transported from the 

 north to the region of perpetual summer cease to lay up 

 stores of honey ^ and lose in a great measure their habits 

 of industry. 



IS How has nature provided for the protection of animals against the 

 modifications of temperature ? 



By covering their bodies with &form of for. or hair, 

 or feathers, in the exact degree required, and to such 



