150 THE OCEAN. 



erect. But if such were the construction in the 

 Whale, the force with which the water rushes into 

 the mouth would inevitably carry a large portion of 

 the fluid down upon the lungs, and the animal would 

 be suffocated. The windpipe is therefore carried 

 upward in a conical form, with the aperture upon 

 the top, and this projecting cone is received into the 

 lower end of the blowing-tube, which tightly grasps 

 it; and thus the communication between the lungs 

 and the air is effected by a continuous tube, which 

 crosses the orifice of the gullet, leaving a space on 

 each side for the passage of the food. 



It is doubtless to give increased power of resist- 

 ance to the eye of the Whale in the pressure of 

 enormous depths, that there is a peculiar thickness 

 in the sclerotic coat. This is the part which in man 

 is usually called the white of the eye. "When we 

 make a section of the whole eye, cutting through the 

 cornea, the sclerotic coat, which is as dense as tanned 

 leather, increases in thickness towards the back part, 

 and is full five times the thickness behind that it is 

 at the anterior part. The fore part of the eye sus- 

 tains the pressure from without, and requires no ad- 

 ditional support; but were the back part to yield, 

 the globe would then be distended in that direction, 

 and the whole interior of the eye consequently suffer 

 derangement. We see, then, the necessity of the 

 coats being thus remarkably thickened behind."* 



Another no less interesting deviation from ordinary 

 structure is found in the skin; the object still being 

 defence against external pressure. Every one is pro- 

 * J>;d.y> Nat, Tbeol, Hell and Brougham's edit. j». 40. 



