while some were comparatively light and nimble, others were comparatively large and clumsy. Now, introducing upon the scene the common ancestor of the lion and the leopard-by immigration either from Asia or from some other adjacent territory now submerged-let us note some probable features of the complex result. First as regards the attacked ruminants, it is likely that in course of time the lightest and swiftest individuals, habitually taking refuge in flight, would have greatly increased both in fleetness and in timidity; the largest and most clumsy of the species, unable to save themselves by fleeing, would often be forced to stand and fight for their lives, and would thus ultimately have gained in size, strength and courage; while those who were neither nimble enough to get out of the way nor strong enough to fight successfully, would have all been killed off. And thus after a while, by perpetual destruction of the means and preservation of the extremes, we should get two kinds of ruminant, as different from one another as the antelope, which escapes by his fleetness and cautious timidity, and the buffalo, which boldly withstands the lion and not unfrequently conquers or repulses him."-(Cosmic Philosophy. vol. ii., p. 18.)

Mr. Fiske here makes three assumptions. (1) He presupposes the pre-existence of two nascent varieties in a given species-some being comparatively light and nimble, others comparatively large and clumsy. (2) He assumes that the light variety would seek safety in flight, and that the heavy variety would try to escape destruction by standing still and fighting for their lives. (3) He takes for granted that the fleetest and most timid of the one section and the strongest and most brave of the other section would be saved, and so a bifurcation of species would take place. But how, I would ask, could the initial difference have arisen in a species which had the same habits? There would be no light and nimble specimens of a race which was never pursued; there would be no heavy and clumsy specimens in a species which had constantly to run for its life. Why should a herd of deer which act for the common good and stick together take to two modes of saving themselves? And there is the second difficulty, already dwelt upon, that the co-operation

of the herd prevents that survival of the swiftest only, which the theory requires.

But we will assume that from some cause or other one or more groups of variants have arisen in connection with a given species. It does not follow that Natural Selection will necessarily interfere. For it is quite conceivable that variant groups may arise which do not differ in any vital point from the parent species. One may have as good a chance of living as the other, and Natural Selection would then not come upon the scene. On the other hand, unfavourable variations, even in their incipient stages, would be suppressed by Natural Selection, if it were a law of nature, so that the co-existence of variants with parental forms cannot be accounted for by the action of Natural Selection.

Again, it is quite possible, when there is sufficient room, that variants might segregate themselves, or adopt different habits, or migrate to a distance, so as not to compete with the parent form. Mr. Darwin admits that, "If both have become fitted for slightly different habits of life or conditions, they might live together."* A good illustration of this point is to be found in the Uria lacrymans :—

"In various parts of the Northern seas a remarkable variety of the common Guillemot (Uria troile) is found; and in Faroe one out of every five birds, according to Graba's estimation, presents this variation. It is characterised by a pure white ring round the eye, with a curved narrow white line, an inch and a half in length, extending back from the ring. This conspicuous character has caused the bird to be ranked by several ornithologists as a distinct species under the name of U. lacrymans, but it is now known to be merely a variety. We thus see that two distinct forms of the same species may co-exist in the same district."-(Descent of Man. p. 424.)

But, for the sake of argument, we will assume that there is a struggle for existence between a group of variants and

Origin of Species. p. 169.

the parent species. It is obvious at the outset that if the variants have less advantage than the parent stock, they will, according to the theory, be destroyed, and then the stability of species, rather than its transmutation, will ensue. If, on the other hand, the variants, which presumably will be in the minority, have the advantage, and if that advantage is gained by the survival of the best among themselves and the destruction of all the rest, the process may be too costly to secure their preservation as a race. It is possible that they might supplant the parent species and yet not permanently establish themselves. The process would always be liable to produce that rarity which is the precursor of extinction; or, if rarity already existed, to convert that rarity into extinction. Other methods of transmutation, on the other hand, which are not dependent upon the accidental emergence of favourable variations, and which do not work by life and death, are not so obnoxious to this danger.

The connection between the extinction of species and Natural Selection appears to be this. A quasi extinction of species is the prelude of transmutation, when all the members of a species undergo modification; but this fact does not necessarily imply that Natural Selection has been at work. The extinction of a whole species obviously prevents the transmutation of that species, whether by Natural Selection or any other cause. There is no reason to suppose that the bifurcation or ramification of species has been produced by Natural Selection; nor does it follow that species and variants will necessarily compete with one another. This conflict can be, and often is, avoided. If conflict did arise, it would either lead to the stability of species, if the parent species survived, or threaten the few surviving favourable variants with extinction. Finally the extinction of species reminds

us of the immense risk which would accompany the action of Natural Selection, if it were indeed a law of nature, while it is obvious that no such risk attends other possible modes of modification. Shall we, then, still say that the extinction is the work of Natural Selection? Shall we say that the extinct species has been "eliminated by Natural Selection?" There is no doubt, in a certain sense, a selection ; one is taken and the other is left." But surely this is not Natural Selection in the proper and definite and technical meaning of the term which implies not the survival of one species at the expense of another; but the modification of a given species by the selection of variations which are useful to the species in the struggle for existence. If a cattle breeder were to kill off all of a particular breed for which there was no longer any demand, you would hardly call that artificial selection.

From what has been said in the two previous chapters, it is certain that the transmutation of species, by whatever means it be brought about, has to compete with the two very different tendencies-the fixity of species and the extinction of species. The stability of species shows us how difficult it is in some cases to bring about any transmutation of species; the extinction of species warns us of the danger which may accompany this attempt. For the reasons which have already been assigned, the competition must be exceptionally bitter in those cases in which the reputed law of Natural Selection is brought into action. Hence it is probable that at the threshold of our enquiry Natural Selection may be excluded where other methods of transmutation are possible.

CHAPTER III.

THE TRANSMUTATION OF SPECIES.

"Corpora vertuntur nec quod fuimusve sumusve

Cras erimus."

-OVID.

WE now propose to ask what part the theory of Natural Selection plays in connection with other possible methods of the transmutation of species.

It may be well, for the sake of clearness, to look at this matter (first) from the point of view of those who believe that Natural Selection is the sole method by which the transmutation of species is brought about, and (secondly) from the point of view of those who believe that transmutation can take place apart from Natural Selection as well as through its agency. In the former case, the principle is laid down that no modification acquired by "the body" of the individual during life can be inherited; that only those variations with which an individual is born can be inherited by the offspring; and that the favourable variations can only survive through the action of Natural Selection—i.e., through selection by life and death.

We must continually bear in mind the reason why the principle of selection is esteemed so important in this connection. Those variations which are necessarily and inevitably associated with sexual reproduction would be swallowed up in the average of the race by the principle of regression to mediocrity, unless similar variants were compelled to breed together. But this principle of selection is only required in the case of those variations which