COSMIC PHILOSOPHY 



nerve. If this view be correct, we have here a 

 truly marvellous instance of differentiation. But 

 now in what way can this structure have ever 

 been useful to human beings in the struggle for 

 life ? Doubtless a considerable power of discrimi- 

 nating sounds is useful to any animal, but of 

 what use can it be to distinguish between A and 

 A-sharp ? We may safely conclude, I think, 

 that survival of the fittest has played quite a 

 secondary part in this case. The explanation 

 must be sought in the direct effects wrought by 

 auditory vibrations upon the molecular struc- 

 ture of the cochlear fibres. And it is a system 

 of effects which has not even yet been wrought 

 in its present completeness save among highly 

 civilized people. A savage cannot distinguish 

 the slight variations in pitch by which our ears 

 are delighted. And even among ourselves there 

 are ears which can neither in melody discrimi- 

 nate between the ascending and the descending 

 gamut, nor in harmony distinguish between the 

 mellifluous tonic chord and the harsh inversions 

 of the minor ninth. The defect may be com- 

 pared to that of colour blindness, although it 

 is probably more common because the ear has 

 been far less thoroughly trained than the eye. 

 Now when we consider how much can be ef- 

 fected by individual training in enabling a mod- 

 erately good ear to discriminate between quarters, 

 eighths, and smaller fractions of a tone, and bear 

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