confidently is the snake's-head lamp-shell (Terebratulina caput serpentis), which lives in our English seas, and abounded (as Terebratulina striata of authors) in the chalk."*

Failing any direct support from palæontology, or from the phenomena of the now-living world, Mr. Darwin's theory can only claim acceptance in so far as it can be shown to be probable from the operation of the three principles of variation, struggle for existence, and natural selection. Whether these are really living and acting principles, or whether they are mere names for non-existences, is the question now to be discussed.

1. Does specific variability exist in nature? The answer to this question would be readily given in the affirmative by a majority of living naturalists; and yet if anything whatever is amenable to proof by observation, experiment, or reason, it can be clearly proved that the answer should be negative.

It needs no accumulation of instances to show that animals vary in form, colour, and generally in what may be called structure. Probably no one animal was ever exactly like another. Any boy who has kept rabbits, pigeons, dogs, cats, or any animals whatever, is as familiar with certain facts of variation as the most learned naturalist. The causes of variation are obscure,-its limits are undefined structurally, but perfectly definite physiologically. It is quite true that by artificial selection the breeder of stock may "not only modify the character of his flock, but change it altogether, he may summon into life whatever form and mould he pleases" (Youatt). It is true as, Lord Somerville observes, concerning the breeders of sheep, that "it would seem as though they had chalked out upon a wall a form perfect in itself, and then had given it existence." But these, and all the instances that can be adduced (and they are innumerable), are the most convincing and irresistible arguments against specific variability. For whilst we can vary form, colour, and structure, indefinitely, the specific physiological characters remain always and absolutely the same. The sheep is always a sheep, the dog is always a dog, the rabbit is always a rabbit, even if we succeed in varying their form and appearance until they are almost unrecognizable as such. The physiological characters, as marked by fertility, are absolutely constant; no variation in this respect, to even the slightest extent, has ever been observed in nature, or developed by art.† To suppose that it can ever begin to be otherwise, is merely an unwarranted conjecture, such as would be rejected summarily in

* On a Piece of Chalk: An Address delivered in 1868, republished in 1874. Lay Sermons, p. 198.

t "Our acceptance of the Darwinian hypothesis must be provisional so long as one link in the chain of evidence is wanting; and so long as all the animals and plants certainly produced by selective breeding from a common stock are fertile, and their progeny are fertile with one another, that link will be wanting.”—Man's Place in Nature, p. 107.

any other science. If any biological position can be established beyond doubt, it is this, that indefinite structural variability, with absolute physiological stability, must be considered as proof that specific differences are not dependent on structure alone; but that they are due to a special endowment not to be traced to the "molecular possibilities of protoplasm."

A species presents two groups of qualities :-A (morphological or structural), and B (physiological or functional). With such certainty as attaches to any of our knowledge, we know that A varies constantly, and within very wide limits; with exactly the same certainty we know that amidst all these variations B remains absolutely constant. The inevitable corollary of this proposition is that B (mathematically speaking) is not a function of A; in physiological language, that function is not essentially dependent upon structure. This truth meets us everywhere in biological research.

By the use of this method, we are compelled to recognize B as indefinitely more important than A, as being a constant quantity, whereas the latter is indefinitely variable. If we are told that our classifications are founded necessarily upon A, it may be replied, without any intention of epigram, "So much the worse for the classification;" for this, to be of any value, should be founded upon constant elements. The truth is, however, that variation. occurs chiefly in non-essential particulars, and has no more effect in altering specific nature, than allowing a man's hair and beard to grow has upon his personal individuality.

Furthermore, there is an entire absence of evidence of any "favourable variation" ever having occurred; and there is an utter vagueness in even surmising what kind of variation might really be favourable in itself, without entailing unfavourable results in its necessary accompaniments.* When we consider also that the supposed variations are so slow, and so infinitesimally minute, that it might require "a million or a hundred million generations"t to establish the characters of a "well-marked variety," we are fairly justified in hesitating to believe in any such inconceivable agencies. If any one proposed to move one of the pyramids by shooting paper pellets at it, he might be logically right in urging that no force, however small, can be lost, and by accumulation must be effective; but we should scarcely argue the question with him. There are two final considerations necessary to be remembered in attempting to form a judgment on this subject. The first is that "varieties" generally manifest a tendency towards reversion

*Mr. Darwin confesses to this difficulty in many places, and often uses such expressions as the following:-"It is good thus to try in our imagination to give any form some advantage over another. Probably in no single instance should we know what to do so as to succeed. It will convince us of our ignorance on the mutual relations of all organic beings; a conviction as necessary as it seems difficult to acquire."-Origin of Species, p. 78. † Ibid. p. 124.

to the original type, when removed from the influence of artificial agencies. The second is this, that although our knowledge of all the circumstances connected with the formation of "races" is very imperfect, yet what we do know with any certainty decidedly opposes the theory of their being formed by slow and minute variations. On the contrary, all the marked instances with which we are acquainted have occurred suddenly, and under conditions of which no adequate explanation could be given; as in the case of the Ancon sheep. This certainly was not an example of selecting and preserving a variation favourable to the individual or to the

race.

2. Is there anything in nature which can be called a "struggle for existence," within the meaning of the hypothesis? Certainly not, if by "struggle" is implied any event or combination of events, the result of which can in any way be influenced by slight individual variations. It is true that all organic beings tend to multiply at a rate which, if unchecked, would in any one instance very soon overstock the earth. The elephant is supposed to breed more slowly than any other known animal; yet at the lowest computation one pair might easily be the ancestors of fifteen millions in five centuries. As to the multiplication of the lower animals, the understanding is baffled in attempting to realize their increase. In five generations, one aphis may be the parent of 5,904,900,000 individuals, and there may be twenty generations in The female flesh-fly will have 20,000 young ones; and in five days any pair of these are qualified to produce as many more; and Linnæus asserts that three flies of the Musca vomitoria could devour the carcase of a horse sooner than a lion. The unchecked produce of one pair of herrings or mackerel would in a very few years crowd the Atlantic until they had no room to move; and it would not require a century for any pair of birds, or any of our domestic animals, so to stock a continent that not an individual of any other species could exist there.

a year.

as

It is evident, then, that of all the countless myriads of living creatures born within any given period, by far the greater part must be destroyed; and this wholesale destruction is effected by means which absolutely preclude any idea of "struggle," influencing the result in the slightest conceivable degree. When clouds of locusts devastate an entire district; when countless millions of aphides destroy vegetation, and are themselves helplessly swallowed up in mass by lady-birds and other enemies; when the great ant-bear destroys thousands of ants, with their single repast; when the Balaenoptera engulfs whole shoals of herrings and smaller fish for a mouthful; when thousands of small fry-shrimps, crabs, molluscs, and medusaench meal of the common Greenland whale; when

dwelling, for a

the bear or the badger destroy and devour the nests of bees wholesale-surely in all this the most vivid imagination can see no room for "struggle," or any possibility of "survival of the fittest." For what advantage could it afford an insect that was about to be swallowed by a bird, that it possessed a thousandth fragment of some property not possessed by its fellows? What preservation against ravages of the slugs would be afforded by an "infinitesimal" difference between one weed and its neighbour? What minute difference would avail the duckling that the fox was about to carry off? These may perhaps be deemed feeble and trifling illustrations; yet it is only by bringing the principle to some such practical test as these that its truth or probability can be recognized. It sounds at first plausible enough to say that profitable variations will naturally tend to the preservation of individuals; but when we put it to the test, and see that it is theoretically improbable, and that there is a total lack of direct evidence that such has ever been the case, we are disposed to look upon it as more sound than sense. The balance of the organic world is preserved by the order of nature, in obedience to which the stronger prey upon the weaker; and against this law, without which nature itself would be a chaotic impossibility, there is no appeal, no resistance, no "struggle."

It must be observed, before leaving this part of the subject, that Mr. Darwin himself, beyond the general idea of struggle and survival, has no definite notion of the circumstances demanding such struggle, nor of its essential nature. The following are only a few out of innumerable illustrations that might be brought forward. In the "Origin of Species," at p. 109, it is stated that "from the high geometrical ratio of increase of all organic beings, each area is already fully stocked with inhabitants, &c. ;" but on the next page it is said that "probably no region is as yet fully stocked." At p. 110 it is stated that "it is the most closely allied forms varieties of the same species, and species of the same genus, or related genera-which, from having nearly the same structure, constitution, and habits, generally come into the severest competition with each other." Here we seem to have arrived at a general principle; but at p. 114 another view requires support incompatible with this, and we are told that "the advantages of diversification of structure, with the accompanying differences of habit and constitution, determine that the inhabitants which thus jostle each other most closely shall, as a general rule, belong to what we call different genera and orders." And at p. 121 (all these occurring in the same chapter, and in different parts of the same argument) we find again that the struggle "will be most severe between those forms which are most nearly related to each other in habits, constitution, and structure." From all which it is not

unnatural to conclude that the idea of "a struggle for existence" is not to be reconciled with the observed facts of nature.

3. If there be any cogency in the foregoing considerations, the conclusion from them is inevitable, that "Natural Selection" is a mere euphuism for a negation—a happy phrase for something that is not representing only a casual residuum after wholesale and indiscriminate destruction. In itself it is absolutely "nothing;' in its application as a theory to individual phenomena, it is full of the most irreconcilable incoherences. Two illustrations only will suffice to show the impossibility of rationally adapting the imaginary principle of natural selection to existing facts. In Madeira there are various kinds of beetles, some having wings largely developed, some having moderate ones, and some without. It is rather amusing to see the manner in which these differences are reconciled to the theory. The large wings are "quite compatible with the action of natural selection. For when a new insect first arrived on the island, the tendency of natural selection. to enlarge or reduce the wings would depend upon whether a greater number of individuals were saved by successfully battling with the winds, or by giving up the attempt, and rarely or never flying." Then in the same page the author adds that certain considerations have made him "believe that the wingless condition of so many Madeira beetles is mainly due to the action of natural selection, but combined probably with disuse. For during thousands of successive generations each individual beetle which flew least, either from its wings having been ever so little less perfectly developed, or from indolent habit, will have had the best chance of surviving from not being blown out to sea; and, on the other hand, those beetles which most readily took to flight would oftenest have been blown out to sea, and thus have been destroyed"! The second instance is taken from the account of the action of natural selection upon certain blind animals in the caves of Styria and Kentucky. Natural selection has acted here. by preserving blind animals, because those which had sight might be subject to inflammation of the nictitating membrane." But it seems that in one of the blind rats the eyes themselves are of "immense size;" and it would appear to be a most extraordinary mistake of natural selection to preserve this animal merely because blind, whilst its "immense " eyes still remain subject to the objectionable inflammation.

If I dwell for a brief space longer upon some of the impossibilities involved in the reception of this theory, it is because, although virtually abandoned by its author, as will be seen presently, it

This phrase is used by Mr. St. George Mivart, in his "Lessons from Nature," p. 300. † Origin of Species, p. 136. Ibid. p. 137