Mr. Darwin tells us, on the same page, that "according to the doctrine that I maintain, the horns of the male elk were slowly gained by sexual selection"; and then, after describing the conflict for the females, adds that "Natural Selection would thus tend to give to the male elk its present structure."

In order to bring in the principle of Natural Selection, we must assume that the variants produced by sexual reproduction are not necessarily organisms composed of co-ordinated parts; that Natural Selection will choose out here a part in one individual and there a part in another individual; that these will survive and intermarry, and thus two elements necessary for the production of a co-ordinated structure, similar to that produced by correlated variation, will be secured. Thus, to take Mr. Darwin's own illustration, Natural Selection will choose out the larger antler of one individual and the stronger neck of another. This idea is full of difficulty. If there is anything in the principle of correlated variation, as applied to individuals, the animal with a larger antler will either have the stronger neck at birth or the neck, compelled to bear the larger weight of the head, will increase in strength through the greater demands made upon it, so that the correlation will be secured before the age of sexual maturity arrives.

If this were not so, it must be because the variation was so slight that any increase of strength in the neck was not required. But if so, Natural Selection could not select such an individual, because it is inconceivable that such a slight difference could make the difference between life and death. But, on the other hand, if the head were made much heavier and the neck were not strengthened, this would be a positive disadvantage to the animal, and it would be apt to succumb in the struggle for existence.

On the other hand, the stronger neck by itself would supply a variation not wanted, and therefore useless.

Again, if we assume that the heavier head was the sole modification in one or in a few individuals, and that the stronger neck was the sole modification in another, then, in order that these two individuals-or, if you will, a small number of such individuals-should intermarry, it is necessary that they alone should survive, and that the others should be all destroyed. That is to say, the injurious variation of the one and the useless variation of the other must triumph over the other members of the group which were perfectly adapted to the conditions in which they lived. Such selection might be possible under the type-producing selection of man, but not through the action of Natural Selection.

But Mr. Darwin says that the antler of the Irish elk has been developed through Sexual Selection. The first stage is thus described :

"Each stag presents individual differences, and in the same district those which had slightly heavier horns, or stronger necks, or stronger bodies, or were the most courageous, would secure the greatest number of does."

Now, first of all, these differences cannot be so very slight, since they are supposed to secure the victory to their fortunate possessors. In the second place, these variants have to compete with the most courageous; and nothing is said about the structure of that combatant. I should be inclined to say that courage would count for more than a slightly heavier head or stronger neck. In the third place, what conceivable advantage could come from a heavier head associated with a neck which had not proportionate strength to use that head as a batteringram? The stronger neck might be useful by itself, but it certainly would be more useful if associated with a

heavier head. A stronger body would avail little to assist its owner, unless the head and neck were also specially developed, though it might cause its owner to protract its defence. Again, are we to suppose that all the heavy heads, and all the strong necks, and all the big bodies compete with those which vary like themselves, and then with those who differ from themselves, somewhat on the same principle as the members of different clubs are chosen to compete in a tennis tournament? And if they did, can you speak with confidence as to which shall prove to be the winner? Supposing that you were a sporting character; on which would you bet,-the slightly stronger head, or the slightly stronger neck, or the more slightly stalwart limbs, or the nondescript of whom we know nothing save his pluck? I venture to think that it would be a game of pure chance. "The offspring of the victor would inherit these same qualities." And yet we must remember that in the harem there are the mothers to be taken into account, and there is also the average of the race to be reckoned with; and it is by no manner of means clear that a slight, abnormal modification, such as we are considering now, will be inherited.

The next stage is the intercrossing. But how can that take place? Only in this way; that the heavier heads should triumph over the stronger necks in one generation, and the stronger necks triumph over the heavier heads in the next generation. But why should this be, except by the merest accident, on which no theory ought to count? And yet it is assumed that this sort of thing can go on till these scattered variations in many organisms can be gathered into a new co-ordinated structure,"always progressing, sometimes in one direction and sometimes in another, towards the present excellently co-ordinated structure of the male elk"!

It follows, then, from what has been said, that the principle of correlated variation obtains in nature; that it will act, whatever cause produces the initial modification in one part; that Natural Selection cannot act in connection with this principle; and that neither Natural Selection nor Sexual Selection can of itself evolve results similar to those produced by correlated variation. We have, then, in the principle we are considering, a very powerful agent in the transmutation of species; but one which affords no reason for supposing that the transmutation of one structure of correlated parts into another structure of parts differently correlated can be brought about through the action of Natural Selection.

CHAPTER V.

PURE DARWINISM.

(a) VARIATIONS SOMETIMES ASSOCIATED WITH SEXUAL

REPRODUCTION.

"Out of the deep, my child, out of the deep,
Through all this changing world of changeless law
And every phase of ever-heightening life,

And nine long months of ante-natal gloom

With this last moon, this crescent, her dark orb
Touched with earth's light-thou comest, darling boy!"
-TENNYSON. De Profundis.

THE argument for pure Darwinism, which asserts that Natural Selection is the sole cause of the transmutation of species, is based upon the belief that no modification of "the body" of an individual can be inherited; that congenital or birth variations can be inherited, and that Natural Selection will choose out the favourable variations which occur. Now in order that this argument should have any validity, it must be tacitly assumed that there are no birth variations, save those which are necessarily and inevitably associated with sexual reproduction; that these variations will not resemble one another through the action of a definite cause; and that there is in nature no other way of isolating similar variants for breeding purposes than by Natural Selection. In this and the following chapter I shall show that these tacit assumptions are not in accordance with the facts of the case.