218 WHALES. 



those species in which it is found, are called spermaceti 

 whales. This substance has nothing to do with sper- 

 matic purposes, neither is it peculiar to whales, but 

 may be obtained from suet, lard, butter, or any other 

 animal fat, and is itself easily changed into a colourless 

 oil, by distillation. Indeed, the fats owe their white 

 colour to its existing in them partially crystallized, just 

 as snow owes its white colour to the little crystals of 

 water it is made of. This great mass of fat, with 

 which the bodies of this species of animals are sur- 

 rounded, is of the utmost importance in their economy. 

 They are, as has been said, warm-blooded animals; 

 and, therefore, their health demands that the tem- 

 perature, through all that part of their bodies where 

 there is a rapid circulation, should be kept as uniform 

 as possible. But the whale is an inhabitant of the 

 most inhospitable seas, and at certain seasons, he may 

 at once be exposed to three great variations of tem- 

 perature. Even when feeding, the whale swims with a 

 considerable portion of its body above water. Now as 

 there is almost always ice, either freezing or thawing, in 

 the northern haunts of the whale, that portion of its body 

 which is in the water must have a temperature of 

 about thirty-two degrees ; the sunny side maybe seventy 

 or eighty, or even higher, and the shady one as low as 

 ten, or even at zero. If the muscles and circulation of 

 the animal were exposed naked to such varieties of 

 heat, the structure would be destroyed; but the oil, 

 which has a slow conducting power, defends it. 



There is one difference between the bones of whales 

 and those of land animals : the texture of the former is 

 loose and spongy throughout, full of pores and of oil, 



