58 THOUGHTS UPOX THE MUSICAL SENSE [X. 



their prey. But this means that they must hear a scale of 

 considerable length ; that, for instance, of the cat must pass 

 through all the interval between the cooing of the wood-pigeon 

 the call of the cuckoo, and the notes produced by the blackbird, 

 the chaffinch, the linnet, the siskin, the thrush, and the pheasant. 

 But the wild animal must also be able to hear the sounds made 

 by its enemies and distinguish them from others. And not only 

 is this the case with the animal sought after by many enemies, 

 such as the rabbit, but the enemy itself must also be upon its 

 guard against other enemies which endanger its life and that of 

 its young. It must distinguish the howl of the hungry wolf 

 from the bark of the fox or dog, the deep note of the eagle owl 

 from the cry of the eagle and vulture. We need not here take 

 man into account, because his existence only began long after 

 the development of the auditory organ in these animals, and 

 because his influence upon them has been annihilating rather 

 than transforming. 



It was therefore necessary for the auditory organs of these 

 animals to have a very extensive range, stretching from rather 

 low notes on the one side to very high ones on the other. It was 

 essential that the organ should be adapted for a continuous 

 scale without breaks ; for otherwise the position of the various 

 notes could not have been accurately estimated. Indeed we 

 feel a sense of admiration and wonder when we see the exceed- 

 ingly high development of the cochlea adapted for hearing a 

 continuous scale in the mammalian ear, and we can only under- 

 stand it when we realize how completely the yery existence of 

 wild animals depends on the utmost delicacy of their organs of 

 special sense. It is absolutely essential for them to know with 

 certainty whether any particular sound proceeds from an enemy 

 or from their prey. While a single mistake might be fatal to 

 them, one often repeated would be inevitably punished with 

 death. If they mistook the sound made by an enemy for that 

 of their prey they would of course go to certain destruction, but 

 the opposite mistake would also be fatal ; for the food of a 

 beast of prey is nearly always scarce, and if many opportunities 

 were missed the animal would die of starvation. It is not in 

 vain that the fox roves about by night and day searching for 

 food, listening for the faintest sound, and ever ready to rush 

 upon its prey or to fly; it is not in vain that the hare is so 



