30 MARINE AND AQCTATIC TEESPASSEES. 



Bat, beneath the skin, fat has been accumulated in 

 prodigious quantities ; and, enveloped in this non-con- 

 ducting material, the whales are fully prepared to 

 inhabit an aquatic medium, and to maintain their tem- 

 perature even in the Polar seas." 



This structure, which is appropriately called by 

 sailors the "blanket," is of a very remarkable cha- 

 racter. There are plenty of animals, notably the swine, 

 the hippopotamus, and the like, which, when in good 

 condition, have a thick layer of fat beneath the skin. 



In all these animals the skin can be removed, 

 leaving the fatty layer in its place. This, however, is 

 not the case with the whale tribes, in which the 

 blubber, as this peculiarly fatty substance is called, is 

 really but a modification of the skin itself, and is com- 

 posed of a mass of interlacing fibres, the spaces between 

 which are filled with oil. A good idea of this structure 

 can be formed by comparing it with that of an orange, 

 the juice of the fruit taking the place of the oil, and 

 the sponge-like cells in which it is held representing 

 the tissues of the skin. Consequently, the skin and 

 the blubber have to be separated by the whaler's 

 <{ spade," before the oil can be expressed from the 

 labyrinthine fibres among which it is entangled. 



Such a substance as this is of necessity exceedingly 

 elastic, and Sir W. Jardine has happily compared it to 

 India-rubber, " possessing a density and resistance 

 which, the more it is pressed, it resists the more.''' The 

 reader will see, therefore, that this wonderful structure 

 fulfils a double duty. In the first place, it acts as a 

 non-conducting layer between the vital parts and the 

 water, thus preserving the animal heat ; and, in the 



