354 PHYSIOLOGY OF THE WHALE. 



by the nature of its integuments. These are three- 

 fold : 



1. The epidermis, scarf-skin, or outermost skin, which 

 is remarkable for its smoothness, and is covered also with 

 a mucous oily fluid exuding from the whole substance, and 

 completely protecting it from injury by the water. 



2. The intermediate skin, or rete mucosum, to which is 

 due the variety of colouring in the various races of man ; 

 it answers the same purpose in the whale tribe. 



3. The true skin, or blubber of the animal, which con- 

 tains its fluid oil, and consists of a mass of fibres crossing 

 and intercrossing each other in every direction. 



An eminent naturalist observes that it is interesting to 

 see how, in the works of nature, an apparently trivial al- 

 teration often effects the most wonderful change. It is so 

 with respect to this true skin. A layer of fat or blubber, 

 even had it been double in thickness to that usually found in 

 the Cetacea, would not have resisted the pressure of the 

 superincumbent ocean- waters ; but the requisite density 

 and power of resistance have been obtained by the modifi^ 

 cation of the skin into a firm and elastic substance, like 

 caoutchouc, not less than eight and sometimes fifteen 

 inches in thickness. 



This firm elastic wrapper, or " blanket," as it has been 

 called, is an indifferent conductor of caloric (or heat). It 

 retains the animal warmth, while it excludes the atmos- 

 pheric cold. Hence it is in this respect admirably adapted 

 as a protection for a warm-blooded animal exposed to the 

 severest cold in the deepest recesses of icy seas. 



The bulk and quantity of this integument is enormous. 

 Sometimes it weighs as much as thirty hundredweight, so 

 that you would naturally suppose it sufficient to overwhelm 



