As a young man 1 was, like the rest, immensely attracted by the doctrine of Natural Selection, and with the high reverence for my old masters, Darwin and Spencer, which was their just due, I strove for years to see all things through it, and to paint the world with its colours. But the paint would not stick; for everywhere the recalcitrant facts, like the thorns of a prickly hedge, would persist in sticking through, and would not take the paint! The same thing happened in a greater or less degree to the specialists themselves. Huxley, the farther he went, the farther he departed from his early belief in Natural Selection as the prime factor in the evolution of species, and the more he became inclined to relegate it to a secondary place; although with his usual honesty and sterling intellectual integrity, not knowing what the really efficient cause of the varieties was, he wisely gave no opinion. And in spite of the efforts of Weismann and his followers to revivify and strengthen Darwin's doctrine by their distinction between 'germ-plasm' and 'body-plasm,' important and necessary as it is, Romanes, and other later observers, the more they came to grapple at close quarters with the facts in their special lines of work, the more they became dissatisfied with the doctrine, until at last they fell away altogether; attributing the facts of variation mainly to "prepotency" and other internal physiological factors, as the agencies which kept the great organic lines of species true to their type by snuffing out through ultimate sterility and decadence all variations that fell outside the limits of permissible oscillation.

But beyond marking out some of the characteristics of these hidden internal causes, they could give no further explanation of them than that so it stood in the will of Providence or Fate. And now with the gaps in the geologic record on which Darwin himself relied for the full demonstration of his theory, largely filled in, the most eminent palaeontologists and geologists, working on the vast accumulation of new facts that have come to light since his time, and tired of the ineffectual effort to plaster a single formula on the infinite variety of Nature and life, have degraded the theory of Natural Selection to a secondary and subordinate position; retaining it rather as a cause of the elimination of the old and unfit, than as a creative cause of the new. Fully developed insects have been found as far back almost as the existence of dry land itself; scorpions of as high a type as those of to-day, and all the present divisions of fishes, as far back as the Upper Silurian; gasteropods in strata where molluscan life was only just beginning; whales in the Miocene; and so on; and, in fact, all attempts to explain the origin of fish, amphibians, reptiles, birds, marsupials, and the higher mammalia by the theory of Natural Selection alone, and without the co-operation of some unseen initiative internal agency, are now gradually being admitted to have been failures.

But the triumphs and limitations of this, our second class of specialisms, namely those which deal with living things, will be best seen, perhaps, in Medicine, which, like Biology, has been so rich in fruit during the last generation. The reason why the specialisms into which it is divided have been so fruitful in results is, that owing to the high preliminary training in the general Science of Medicine which each specialist has received, and to the fact that each, by means of the medical journals and the constant stream of new text books, is kept closely in touch with all the advances made in that general science, medical specialism has always worked under the guiding influence and direction of the Science of Medicine as a whole. And, although that Science is still far from perfect, its advance to a greater and greater perfection proceeds, by means largely of these specialisms, steadily and unweariedly; the knowledge gained through the minute investigation of special organs and functions returning to enrich the general science which deals with the relations of them all, while that in turn stimulates and directs anew the current of inquiry to ever fresh problems in the out-lying field.

When I came to London to collect material for my philosophical work, whole regions of what are now the common-places of Medicine were mere blanks on the map. All the finer forms of paralysis and other diseases of the brain and spinal cord, with their symptoms and signs; the part played in the causation of the specific fevers, as well as in other inflammations, by germs; the entire range of antiseptic surgery, which has reduced the death-roll in certain operations from ninety-five to five per cent.; all this was then a terra incognita, and it has all been the result of specialism. And although successful treatment still lags far behind (for who can restore an organ destroyed by dissipation or disease, any more than he can restore an amputated limb?), it may truly be said that the diagnosis of all the organic diseases which tend to shorten life has been brought in the hands of the great masters of the profession almost to a working certainty. And yet it is strange how little this is recognised by the general public, whether educated or uneducated.

The reason, I think, lies in the difficulty often experienced in treating successfully those purely functional disorders, which, depending, as they of ten do, on under or over stimulation of the different parts of the nervous system, too frequently lie beyond the reach either of diet, regimen, or drugs. And, moreover, where the profession fails, the charlatan, the hypnotist, the faith-healer, and the Christian Scientist often succeed, by the one method common to their respective callings, namely by taking advantage of that mysterious power that can be exerted by the mind over the body, and which in some of its most effective forms honourable medical men cannot, or dare not, employ; whether it be the solemn pose of the quack, the testimonial advertisements of the patent-pill man, the suggestion of the hypnotist, or the simple logic of the Christian Scientist who, if you will only grant him that God is good, and that the world was created by God, will prove to you that there can be no evil or pain except in your own imagination, and treat you accordingly.