THE FACULTY OF HEARING. 359 



from which we draw certain inferences based on the experience of 

 our own self-consciousness. We assume, namely, that the insect 

 movement is made in response to sensations associated with its 

 consciousness and will. Thus the movement of antennse in the 

 direction whence the sound which the insect is supposed to hear 

 proceeds, is interpreted as a gesture (that is, expression of 

 sentiment) induced by that sound. But though we may be 

 convinced that this movement really occurs in the same order and 

 with the same constancy, and always in obedience to the same call, 

 we are not justified in inferring a coiiscious intent in the action, 

 perhaps not even any cerebral conciousness of the stimulus (the 

 sound or vibratory impression) which is responded to as a reflex 

 action upon a local sensation. But be this as it may, the movement 

 of a feeler cannot reasonably be compared with the pricking up of 

 the ears of a horse or a hunted animal, in proof that the ear is 

 located in the antennae, for the same response to external call sets 

 in motion the legs, wings, and any other moveable appendages 

 alike. In the next place if our conjecture has arisen from 

 observation of outward resemblance or analogy of known organs, 

 whether there be any force or not in the comparison, we thereby 

 commit ourselves to a principle which we are bound to follow out 

 further. If we examine the arrangement and structural character 

 of any organ accredited with a given function, in order to ascertain 

 whether the special physical requirements of that function are 

 suitably met, we cannot stop at the first step and conclude, for 

 instance, that because an elastic expansion of skin can be set in 

 vibration by the impulse of vibratory waves from without, it must 

 therefore be an auditory organ. We might as well consider every 

 transparent part of an insect specially adapted for vision. The 

 generaHsations of the non-scientific observer seldom however go 

 beyond this, audit remains for the expert to follow up the analysis 

 of function and the anatomy of the organ, combining the study of 

 physical phenomena with that of the material structure, until he 

 has reached the final anatomical element and all traceable material 

 phenomena come to an end. 



