THE SHARK'S TEETH 



However surprising this may seem, there is a reason 

 for it. Despite an organic strength not surpassed by 

 any vertebrates on land, the sharks display some 

 traces of their earlier condition. The whole of their 

 inner skeleton is made of cartilage. Bony tissue only 

 occurs in the skin, reinforcing and consolidating the 

 material of the scale-like denticles with which it is 

 covered; it supplies the ivory, which, coated with 

 enamel, gives the rough skin its firmness and hardness. 

 The shagreen used by cabinet-makers for polishing is 

 nothing but the skin of certain kinds of shark, specially 

 prepared and fitted for its particular purpose because 

 of its roughness. 



The teeth are projections of the same sort, composed 

 of the same material, and different from those of the skin 

 only by being larger and occupying a more specialized 

 position ; they are definitely fixed at the entrance of the 

 mouth. The mucous membrane round the mouth 

 cavity or on the lips has the same origin and the same 

 essential constitution as the skin which covers the 

 body; it too is able to produce exactly similar struc- 

 tures; it forms them and, because of their peculiar 

 situation, they act as teeth. This is true of all verte- 

 brates, whatever they may be; their teeth, despite 

 their appearance and function, are neither more nor 

 less than skin structures. In that sense they belong 

 to the same category as scales proper, feathers, and 

 hair. 



Having got so far, we arrive at our first conclusion. 

 The shark, lying on the pebbly beach after being 

 landed from the fisherman's boat, may display its fine 

 set of terrible teeth as much as it likes. When we come 

 to examine this alarming spectacle, we find that it 

 is only an exhibition of weakness. It falls to the level 

 of a mere ornament. As such, it is imposing enough, 

 and when its possessor is alive in the water, it is free 

 to exercise the prerogatives such an instrument con- 

 fers, but, by itself, it by no means bestows upon the 



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