THE ''SPOUTING'' OF WHALES. 67 



ment has, therefore, been provided for it, and for almost all 

 whales, by which that difficulty is removed. Instead of 

 running along the bones of the nose, the nostrils are placed 

 on the top of the head, and the windpipe is turned up to 

 them without having any connection with the palate. The 

 upper jaw is quite solid. Thus the mouth is solely devoted 

 to the reception of food, and the animal is enabled to con- 

 tinue its course when swimming, however rapidly, by rising 

 obliquely to the surface, and exposing the top of its head 

 above it. On the blow-hole being opened, the air, from 

 which the oxygen has been absorbed, is expelled in a 

 sudden puff, another supply is instantaneously inhaled, and 

 rushes into the lungs with extreme velocity, and then the 

 porpoise can either descend into the depths, or remain with 

 its spiracle exposed to the air, as it may prefer. In this 

 act of breathing the spiracle is normally brought above the 

 water, the breath escapes, and the immediate inhalation is 

 effected almost in silence. But frequently, and in some 

 whales habitually, the blow-hole is opened just below the 

 surface, and then the outrush of air causes a splash upwards 

 of the water overlying it. 



I may here mention that I have frequently seen the 

 porpoises at the Brighton Aquarium lying asleep at the 

 surface, with the blow-hole exposed above it, breathing 

 automatically, and without conscious effort. Aristotle was 

 acquainted with this habit of the cetacea 2,200 years ago, 

 for he wrote : " They sleep with the blow-hole, their organ 

 of respiration, elevated above the water." 



The apparatus for closing the blow-hole, so that not a 

 drop of water shall enter the windpipe, even under great 

 pressure, is a beautiful contrivance, complex in its structure, 

 yet most simple in its working. The external aperture is 

 covered by a continuation of the skin, locally thickened, and 



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