THE SHARK'S TEETH 



We are often told that the function produces the 

 organ. The expression itself, or its variants and 

 derivatives, " the function creates the organ " or " the 

 function develops the organ ", is repeated on all 

 occasions and is supposed to be an explanation in 

 itself. In it, above and beyond its appropriate acts, 

 the function appears to possess a creative role which 

 consists in fashioning or perfecting a structure adequate 

 to its requirements. We seem to have a very striking 

 example of this in the case of the shark's teeth. The 

 keen appetite in the shark can only be satisfied if it 

 possesses organs which have the power -to seize prey; 

 its size, which is considerable, gives the measure to 

 the essential weapons, and these must be proportionate 

 to that size in number, strength, and capacity for 

 attack and defence. The function which, in this 

 particular instance, is the taking of nourishment, thus 

 finds in the organ, that is the tooth, the instrument 

 it has created to fulfil itself. And both agree so well 

 that the tooth appears to have been made according 

 to a model suited to the requirements of such a voracious 

 nature. 



One day I happened to have a very good view of a 

 large shark in the water. It was on one of my ex- 

 cursions fishing with the gangui among the grass- 

 wrack of the submarine prairie. The net had just 

 been brought in and hauled on deck, and I was leaning 

 over the side watching a little shell-fish which had 

 dropped out of the net and was slowly zigzagging its 

 way to the bottom. At that particular instant, a 

 shark, attracted doubtless by the bait of the fish 

 caught in multitudes in the meshes of the net, slowly 

 passed below the keel, almost touching it. This only 

 took an instant, but I had time enough to realize what 

 the creature was like and of what it was capable. Its 

 length, measuring it by that of my boat, must have 

 been between thirteen and sixteen feet, and its greatest 

 breadth about three feet. The beast was leaning over 

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