We have now come to the end of our discourse upon the theories of odour, and it must be confessed that we are still very much in the dark as to the nature of the odorous, and as to the manner in which it excites the olfactory organ to activity.
Still more mysterious, however, is the process by which the physical quality of odour becomes the sensation of the mind we call smell.
The transmutation of a physical quality into a sensation is indeed the great mystery of all our senses. Olfaction is not the only one before which we throw up our hands, and this in spite of the detailed and voluminous information which modern physiology, neurology, and psychology place at our disposal, perhaps less in spite of this information than because of it, seeing that the further our knowledge extends the wider seems the unknown realm beyond. Our science is an ever-expanding sphere, no doubt, but it is expanding into the infinite.
How is it that the rhythmic vibration of matter becomes what we call “sound,” or the rhythmic vibration of the ether “light” ?
Tow does the physical pass into and become part of the psychic ?
According to recent teaching, the physical can be followed as such from the sensory end-organ itself as far as the first synapse, or junction with
