organisms eventually so changed, that, compared with their antecedents or originals, they cannot be denied to be new species. Assume the change to be one of advantage, then the accumulation of necessarily increasing differences can only end in the production of a new creature. Mr. Darwin is resolute in his adherence to this, that there shall be no design from elsewhere -that the whole appearance of contrivance and construction shall be due to nothing else whatever than, so to speak, to this mechanical pullulation of differences, that can only end in such mechanical accumulation as can be only tantamount to a new species. Of course, it is plant life, animal life, that so pullulates or develops; and it is not denied that life may be more than mechanism. But still, as in life, the process here can only be called mechanical. We only assume it to be certain that organisms do vary, and quite as certain that any variation they present is in the first instance no more than an accident a simple appearance of chance. Even the influence of conditions is not to be taken into account: the same organism may exist under any conditions whatever, from the north to the south, or from the east to the west. Conditions or no conditions, it is the appearance of difference alone that is crucial-difference into advantage, and accumulation of difference into advantage, until by mere process of natural eventuation of steps the old has become new-out of one species another has been evolved. This, whatever may be said, is the genuine Darwin. Mr. Darwin has been much impressed by the progress of physical science -by the enormous revolution in it which the discovery of one law-the attraction of gravity-has accomplished, and it would rejoice his heart to introduce a like natural simplification into the process of organic change. As primal condition of the realization of this process, Mr. Darwin expressly excludes (ii. 176 s.) any necessity to

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principle of improvement;" it is enough that there be granted "only diversified variability." And "so," he says, " under nature any slight modification which chances to arise, and is useful to any creature, is selected or preserved in the struggle for life." To Mr. Darwin, the slight modification only "chances" to arise-chances in italics! This one passage is decisive; but there are many such. He says once to Lyell, for instance: "No change will ever be effected till a variation in the habits or structure, or of both, chance to occur in the right direction, so as to give the organism in question an advantage over other already established occupants of land or water; and this may be, in any particular case, indefinitely long." And the word chance is again underlined. To Hooker, too, he speaks in the same conviction. "The formation of a strong variety, or species," he says (ii. 87), " I look at as almost wholly due to the selection of what may be incorrectly called chance variations or variability; " and again he italicizes chance. The adverb "incorrectly," namely, is only added under the influence of common parlance. The physical, natural changes, that are the groundwork of the theory, are to him as physical, natural-results of mere mechanical play that may be named chance, or, as he says elsewhere, accident. His one desire, indeed, is to keep this chance, this accident, pure. Under it alone he would see a difference arise for a consequent series of differences, by propagation, heredity, to accumulate. So it is that he manifests most unmistakably, and almost everywhere, a rooted disinclination to consider any diversity in organisms as the result of an alteration in external conditions. Courtesy was the very nature of Mr. Darwin; and under its leading he goes always so far as ever he can in agreement with his

various correspondents. In a letter to Herr Moritz Wagner, for example, who seems to have accentuated conditions, "I wish I could believe," he says with all gentleness,-" I wish I could believe in this doctrine (the agency of changed conditions), as it removes many difficulties." Even here, however, his wish for, is followed by his objections to. No doubt, Herr Wagner is not the only correspondent to whom there may be some polite expression of favour, more or less, for conditions; but even within a year of his death, in writing to Professor Semper with reference to Professor Hoffmann's experiments in discredit of conditions, he ventures to tell the former, -"I thought you attributed too much weight to the direct action of the environment; - changed conditions act, in most cases, in a very indirect manner." Elsewhere in these letters, when he judges his correspondent to be with him, there is to be found quite a superfluity of expressions unexceptively averse to the belief in conditions. To Hooker, for example, he says once, "The conclusion I have come to is that external conditions (to which naturalists so often appeal) do by themselves very little;" and this very little is an italicized very little. On another occasion he finds "the common notion absurd that climate, food, etc., should make a pediculus formed to climb hair, or woodpecker to climb trees." " I quite agree with what you say about the little direct influence of climate," he seems quite glad to tell Hooker at another time. To Thomas Davidson, again, he courteously and concessively admits, "I oscillate much on this head;" still he takes heart to intimate that he "generally returns to his belief that the direct action of the conditions of life has not been great." To Lyell, he throws off every rag of reserve, and actually swears. "I feel inclined to swear at climate" (ii. 174), he says; no error is more mischievous than this" (ii. 169); and again, "It has taken

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me so many years to disabuse my mind of the too great importance of climate that I am inclined to swear at the North Pole, and, as Sydney Smith said, 'even to speak disrespectfully of the Equator; and then he bids Lyell reflect how readily acclimatization is effected under nature "-how "thousands of plants can perfectly well withstand a little more heat and cold, a little more damp and dry," etc. As all inorganic phenomena are under the law of physical gravitation, so Mr. Darwin would wish all organic phenomena to prove under the law of mere physical variation. So it is that he dislikes all reference to conditions. It is very natural that one, for a time, should fail to see this in Mr. Darwin; for the influence of conditions is so glaringly conspicuous. so palpably indispensable indeed, that it takes long to be prepared for their denial. Nevertheless, it is obvious from these quotations and they might be largely augmented-that he who insists on conditions as elements in the construction of an organism, cannot be in agreement with, but is in opposition to, Mr. Darwin. And it is here that Mr. Huxley puts us to some difficulty -not for his opinions, but only in his use of the phrase "external conditions." As regards the 1844 Essay, for example, he points out to Mr. Darwin's son that in it "much more weight is attached to the influence of external conditions in producing variation, and to the inheritance of acquired habits, than in the Origin;" while to Mr. Darwin himself he had, after reading his book in 1859, remarked, and the remark is the second of the only two objections that have occurred to him, "it is not clear to me why, if continual physical conditions are of so little moment as you suppose, variation should occur at all" (ii. 231). Mr. Huxley, from these quotations, had evidently observed that Mr. Darwin put little moment on physical conditions, and that this tendency on his part was stronger on a later occasion than

on an earlier. Evidently, also, Mr. Huxley was so far in disagreement with Mr. Darwin. It cannot be so far, then, that we mean Mr. Huxley to have put us to any relative difficulty. No; the reference in that case is to a passage in Mr. Huxley's writing, just of the other day, which (Life and Letters of Charles Darwin, vol. ii. p. 195) runs thus: "The suggestion that new species may result from the selective action of external conditions upon the variations from their specific type which individuals present and which we call 'spontaneous,' because we are ignorant of their causation-that suggestion is the central idea of the Origin of Species, and contains the quintessence of Darwinism." Here external conditions," as we see, have become the very motor, and agent, and source, and spring of Darwinism; and they do give difficulty, if they are to be supposed the same as before. But they are not to be so supposed -they are not the same as before. No, very far from that! The conditions then were supposed to precede the variation: the conditions now are supposed to follow it. Or, while the former were the conditions that brought about the variation, the latter, again, are those that only take advantage of it. The first set of conditions were those of climate, - heat and cold, damp and dry, -food, etc. What the second set refers to quite otherwise-are the increased means of nourishment, support, shelter, security, which have been already described as the advantages on the part of nature, pictured in the theory, to be consequent upon the variation. As was said then: It is on the variation that Nature operates her selection; or, as it may be otherwise conceived, the selection is operated on nature by the variation. Now, that is the whole meaning of Mr. Huxley in the apparently discrepant usage of the phrase "external conditions," in his respective passage that has just been quoted. Further, as we may allow ourselves to note, when, in the same