A vestige in biological writings is almost the exclusive property of the Pan-Selectionists, and no one can doubt that on the one hand it is a far more correct term than that of rudiment which Darwin employed so freely, on the other that they have a perfectly legitimate claim to it in a large number of obsolete structures of animal forms. But vestiges, footsteps, footprints, have another and equally correct meaning, even if less often thus employed, in the fact that a vestige or footprint may just as well be a relic of what the race and individuals have done, as a relic of what they have retained in the way of possession, and I submit that the facts and arguments I have here advanced afford a valid claim to the term “vestige” in the results of certain doings on the part of animals—as will appear later still more clearly.
The term “normal” is a fine field for dialectics, but neither ordinary men nor scientific students can do their work without its use, and yet it would have been an intellectual treat to have heard how Huxley, for example, would have turned inside out any opponent who chose to employ it to his dissatisfaction. In a strictly-conducted tournament no evolutionary biologist would allow its use—to his adversary. A norm for him exists only as one of Professor Karl Pearson’s “conceptual counters,” a piece of mental shorthand or hardly more than a pis aller. Among the fundamental conceptions of organic evolution there is one which is almost a truism, the doctrine of Heraclitus, πἁντα ρε̑ι, the everlasting flux and change of Nature and her products. In strict logic, according to what we all now believe, there is no possible norm. All that one may do is to take stock at a certain epoch of evolution and label, for our own convenience, some group, or organism or structure as “normal”—and go on with our business, collecting some specimens, calling them type-specimens, and putting them in books or cases in the Natural History Museum—and then proceed to business.
The biological teacher in his class room says he must live, he must have his tools for his work, to which the idle student replies under his breath, “I do not see the necessity,” but then few students are now idle, and this jibe does not sting any one! The examiner must have his normal human anatomy, and would ruthlessly plough any daring examinee who tried to sophisticate the meaning of the term “normal.” I have often been struck with what I must call the intellectual audacity of a most eminent leader in physical science and mathematics, who is not unlike a certain great Church, which grants nothing to her adversaries but is not averse from taking. In his Grammar of Science, written with a pen dipped in hydrochloric acid, Professor Karl Pearson four times over, and perhaps more, has the courage to call the human brain in this twentieth century “normal.” Has he never heard of the coming Superman of Mr. Bernard Shaw and other prophets? Thinking sub specie aeternitatis has he here in the West, and at a certain small epoch of time, any right to call the human brain “normal”? I can only long that there may be more normal brains such as Professor Karl Pearson’s, and am almost inclined to echo the prayer of Moses, “Would God all the Lord’s people were [such] prophets”! These comments on the term “normal” imply no complaint against its use, indeed are a claim for it, and I deprecate very much that form of criticism known in boys’ schools, domestic circles, and among politicians as the tu quoque reply, and I hope the few ambiguous terms used in this book will pass the censor, and help the reader.
CHAPTER VII.
THE EVOLUTION OF PATTERNS OF HAIR.
Some attention must here be given to the supposed mode of formation of individual patterns of hair, that is to say, their evolution. So here one has to move among the fields of hypothesis, without which detached facts of nature are useless to science.
The simplest pattern consists of a reversed area of hair appearing between two adjoining streams; the more complex are whorls, featherings and crests. No detailed description nor illustration of the former are required, but I have prepared a diagram to illustrate the latter (see p. 51.) (A) shows a whorl by itself; (B) a whorl, feathering and crest. The arrows at the sides indicate the direction of the adjoining hair-streams, the arrow in the centre of (B) the direction of the reversed flow of hair.