SUPERIORITY OF OUR SEXSES. 375 



Few subjects are of greater interest to the pliiloso- 

 pliic mind than the gradual complication of the organ 

 of hearing, with, of course, its proportional complica- 

 tion of function, in the animal series. Even in human 

 beings we see differences only less considerable than 

 those which exist between man and animals. The ear 

 of one man is utterly incapable of appreciating those 

 delicate intervals and harmonic combinations which 

 give to another exquisite delight. The bird, 



" Singing of summer in full-throated ease," 



is insensible to music, and probably distinguishes 

 nothing in sj^eech except the loudness of the tone. And 

 this fact may lead us to question whether the general 

 notion, so often insisted on, of the superiority in the 

 senses of animals over those of man, is not a fallacy. 

 It is quite true that a bird sees distinctly at greater 

 distances than a man ; but can it see such delicate 

 nuances of colour ? A dog perceives some odours to 

 which we are insensible ; but in the immense varieties 

 of odours we are capable of perceiving, our superiority 

 is manifest. In hearing, animals are demonstrably 

 inferior. Some of them may be as susceptible to certain 

 sounds, but none are susceptible to the immense variety 

 of sounds distinguishable by our ears. 



Before quitting our Molluscs, let us for a moment 

 consider the shells with which the vast majority are 

 furnished, and with which all are furnished in their 

 embryonic state. I do not mean that we should lose 

 ourselves in the varieties of a concholooist's collection, 

 nor that we should inquii'e minutely into the structure 



