CETACEA. 



in which is contained the oil. If a hog be skinned, 

 the fat is left lying upon the flesh, but it is impos- 

 sible thus to tear off the skin of the Whale ; if suf- 

 ficient force be applied, the whole skin and oil will 

 come up together. Mere fat would not have resisted 

 the pressure, but this structure acts with the elasticity 

 of so much India-rubber, (sometimes more than a 

 foot thick,) possessing a density and resistance, 

 which, the more it is pressed, resists the more.* 

 This thick coat of fat, a non-conductor of heat, 

 acting as a blanket, serves to prevent the chilling 

 influence of the Arctic Seas upon the blood, and keeps 

 the animal heat uniform. 



As the Cetacea must come to the surface to breathe, 

 it was expedient that as small a surface should be 

 exposed on such occasions as possible : hence the 

 nostrils open at the very crown of the head, by an 

 orifice called the blow-hole, through which is also 

 ejected the water taken in with the food. The 

 closing of this aperture when beneath the water, is 

 effected by a very beautiful valvular apparatus, a 

 stopper of great resisting power. 



Many witnesses have borne testimony to the anxi- 

 ous affection which some of the larger species exer- 

 cise towards their offspring : the mother " holding 

 them beneath her fins, and protecting them with the 

 greatest care and courage from every assailant." 



Enjoying means of progression so extensive, living 

 in a medium but little affected by variations of 

 climate, the Cetacea are not generally bounded by 



* Nat. Lib. Mammalia, vol. vii. p. 48. 



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