Olfaction and Odours

If we possessed a true, well established and undoubted theory concerning the function of the nerves in the human body, the principles of smell would be much easier to understand. So far, we do not know for certain whether the action of nerves takes place by means of a subtle fluid, which is instantaneously conveyed from the beginning of the nerves to their ends, or whether, as some think, some sor...