138 THE OCEAN. 



a thick coat of fat, denominated blubber, varying in 

 diameter from eight inches to nearly two feet in 

 different parts of the animal. It has, however, been 

 only recently known that this fat lies not under the 

 skin, but actually in its substance. I shall describe 

 this in the words of Professor Jacob, who first made 

 known this interesting peculiarity : — " That structure 

 in which the oil is deposited, denominated blubber, 

 is the true skin of the animal, modified certainly for 

 the purpose of holding this fluid oil, but still being 

 the true skin. Upon close examination it is found 

 to consist of an interlacement of fibres, crossing each 

 other in every direction, as in common skin, but more 

 open in texture, to leave room for the oil. Taking 

 the hog as an example of an animal covered with an 

 external layer of fat, we find that we can raise the 

 true skin without any difficulty, leaving a thick layer 

 of cellular membrane, loaded with fat, of the same 

 nature as that in the other parts of the body ; on the 

 contrary, in the Whale it is altogether impossible to 

 raise any layer of skin distinct from the rest of the 

 blubber, however thick it may be ; and, in flensing a 

 Whale, the operator removes this blubber or skin 

 from the muscular parts beneath, merely dividing 

 with his spade the connecting cellular membrane." * 

 Such a structure as this, being firm and elastic in the 

 highest degree, operates like so much India-rubber, 

 possessing a density and power of resistance wdiich 

 increases with the pressure. But this thick coating 

 of fat subserves other important uses. An inhabitant 

 of seas where the cold is most intense, yet warm- 



• Dublin Philos. Journ. i. 356. 



