The contention of those who refuse to admit man unreservedly into the scheme of evolution is comparatively recent. The great propounders of evolution, Buffon, Erasmus Darwin and Lamarck--not to mention a score of others who wrote at the close of the last and early part of this present century--had no qualms about admitting man into their system. They have been followed in this respect by the late Mr. Charles Darwin, and by the greatly more influential part of our modern biologists, who hold that whatever loss of dignity we may incur through being proved to be of humble origin, is compensated by the credit we may claim for having advanced ourselves to such a high pitch of civilisation; this bids us expect still further progress, and glorifies our descendants more than it abases our ancestors. But to whichever view we may incline on sentimental grounds the fact remains that, while Charles Darwin declared language to form no impassable barrier between man and the lower animals, Professor Max Muller calls it the Rubicon which no brute dare cross, and deduces hence the conclusion that man cannot have descended from an unknown but certainly speechless ape. It may perhaps be expected that I should begin a lecture on the relations between thought and language with some definition of both these things; but thought, as Sir William Grove said of motion, is a phenomenon "so obvious to simple apprehension, that to define it would make it more obscure." {17} Definitions are useful where things are new to us, but they are superfluous about those that are already familiar, and mischievous, so far as they are possible at all, in respect of all those things that enter so profoundly and intimately into our being that in them we must either live or bear no life. To vivisect the more vital processes of thought is to suspend, if not to destroy them; for thought can think about everything more healthily and easily than about itself. It is like its instrument the brain, which knows nothing of any injuries inflicted upon itself. As regards what is new to us, a definition will sometimes dilute a difficulty, and help us to swallow that which might choke us undiluted; but to define when we have once well swallowed is to unsettle, rather than settle, our digestion. Definitions, again, are like steps cut in a steep slope of ice, or shells thrown on to a greasy pavement; they give us foothold, and enable us to advance, but when we are at our journey's end we want them no longer. Again, they are useful as mental fluxes, and as helping us to fuse new ideas with our older ones. They present us with some tags and ends of ideas that we have already mastered, on to which we can hitch our new ones; but to multiply them in respect of such a matter as thought, is like scratching the bite of a gnat; the more we scratch the more we want to scratch; the more we define the more we shall have to go on defining the words we have used in