Mr. Darwin also says: "There is reason to believe that insects are affected by confinement like the higher animals," and he gives examples.' 12 Again, he gives examples of change of plumage in the linnet, bunting, oriole, and other birds, and of the temporary modification of the horns of a male deer during a voyage.1a Finally, he adds that these changes cannot be attributed to̟ loss of health or vigor, "when we reflect how healthy, long-lived, and vigorous many animals are under captivity, such as parrots, and hawks when used for hawking, chetahs when used for hunting, and elephants. The reproductive organs themselves are not diseased; and the diseases from which animals in menageries usually perish, are not those which in any way affect their fertility. No domestic animal is more subject to disease than the sheep, yet it is remarkably prolific. . . . It would appear that any change in the habits of life, whatever these habits may be, if great enough, tends to affect in an inexplicable manner the powers of reproduction. Such, then, is the singular sensitiveness of the generative system. As to the means by which that system is affected, we see that a variety of conditions affect it; but as to the modes in which they act upon it, we have as yet little if any clew. We have also seen the singular effects (in tailed Lepidoptera, etc.) of causes connected with geographical distribution, the mode of action of which is as yet quite inexplicable; and we have also seen the innate tendency which there appears to be in certain groups (birds of paradise, etc.) to develop peculiarities of a special kind. It is, to say the least, probable that other influences exist, terrestrial and cosmical, as yet unnoted. The grad 12 “ Animals and Plants under Domestication," vol. ii., p. 157. ually accumulating or diversely combining actions of all these on highly-sensitive structures, which are themselves possessed of internal responsive powers and tendencies, may well result in occasional repeated productions of forms harmonious and vigorous, and differing from the parental forms in proportion to the result of the combining or conflicting action of all external and internal influences. If, in the past history of this planet, more causes ever intervened, or intervened more energetically than at present, we might a priori expect a richer and more various evolution of forms more radically differing than any which could be produced under conditions of more perfect equilibrium. At the same time, if it be true that the last few thousand years have been a period of remarkable and exceptional uniformity as regards this planet's astronomical relations, there are then some grounds for thinking that organic evolution may have been exceptionally depressed during the same epoch. Now, as to the fact that sudden changes and sudden developments have occurred, and as to the probability that such changes are likely to occur, evidence was given in Chapter IV. In Chapter V. we also saw that minerals become modified suddenly and considerably by the action of incident forces-as, e. g., the production of hexagonal tabular crystals of carbonate of copper by sulphuric acid, and of long rectangular prisms by ammonia, etc. We have thus a certain antecedent probability that if changes are produced in specific manifestation through incident forces, these changes will be sensible and considerable, not minute and infinitesimal. Consequently, it is probable that new species have appeared from time to time with comparative suddenness, and that they still continue so to arise if all the conditions necessary for specific evolution now obtain. This probability will be increased if the observations of Dr. Bastian are confirmed by future investigation. According to his report, when the requisite conditions were supplied, the transformations which appeared to take place (from very low to higher organisms) were sudden, definite, and complete. Therefore, if this is so, there must probably exist in higher forms a similar tendency to such change. That tendency may indeed be long suppressed, and ultimately modified by the action of heredity-an action which would increase in force with the increase in the perfection and complexity of the organism affected. Still we might expect that such changes as do take place would be also sudden, definite, and complete. Moreover, as the same causes produce the same effects, several individual parent-forms must often have been similarly and simultaneously affected. That they should be so affected—at least that several similarly-modified individuals should simultaneously arise-has been seen to be a generally necessary circumstance for the permanent duration of such new modifications. be en It is also conceivable that such new forms may dowed with excessive constitutional strength and viability, and with generative prepotency, as was the case with the black-shouldered peacock in Sir J. Trevelyan's flock. This flock was entirely composed of the common kind, and yet the new form rapidly developed itself, "to the extinction of the previously-existing breed.” 1o Indeed, the notion accepted by both Mr. Darwin and Mr. Herbert Spencer, and which is plainly the fact (namely, that changes of conditions and incident forces, within limits, augment the viability and fertility of individuals), harmonizes well with the suggested possibility as to an augmented viability and prepotency in new organic forms evolved by 14 "Animals and Plants under Domestication," vol. i. p. 291. peculiar consentaneous actions of conditions and forces, both external and internal. The remarkable series of changes noted by Dr. Bastian were certainly not produced by external incident forces only, but by these acting on a peculiar materia, having special properties and powers. Therefore, the changes were induced by the consentaneous action of internal and external forces. 15 In the same way, then, we may expect changes in higher forms to be evolved by similar united action of internal and external forces. One other point may here be alluded to. When the remarkable way in which structure and function simultaneously change, is borne in mind; when those numerous instances in which Nature has supplied similar wants by similar means, as detailed in Chapter III., are remembered; when also all the wonderful contrivances of orchids, of mimicry, and the strange complexity of certain instinctive actions are considered-then the conviction forces itself on many minds that the organic world is the expression of an intelligence of some kind. This view has been well advocated by Mr. Joseph John Murphy, in his recent work so often here referred to. This intelligence, however, is evidently not altogether such as ours, or else has other ends in view than those most obvious to us. For the end is often attained in singularly roundabout ways, or with a prodigality of means which seems out of all proportion with the result: not with the simple action directed to one end which generally marks human activity. Organic Nature then speaks clearly to many minds of the action of an intelligence resulting, on the whole and in the main, in order, harmony, and beauty, yet of an intelligence the ways of which are not such as ours. 15 Though hardly necessary, it may be well to remark that the views here advocated in no way depend upon the truth of the doctrine of Spontaneous Generation. This view of evolution harmonizes well with theistic conceptions; not, of course, that this harmony is brought forward as an argument in its favor generally, but it will have weight with those who are convinced that Theism reposes upon solid grounds of reason as the rational view of the universe. To such it may be observed that, thus conceived, the Divine action has that slight amount of resemblance to, and that wide amount of divergence from, what human action would be, which might be expected a priori-might be expected, that is, from a Being whose nature and aims are utterly beyond our power to imagine, however faintly, but whose truth and goodness are the fountain and source of our own perceptions of such qualities. The view of evolution maintained in this work, though arrived at in complete independence, yet seems to agree in many respects with the views advocated by Prof. Owen in the last volume of his "Anatomy of Vertebrates,” under the term "derivation." He says: 16" Derivation holds that every species changes in time, by virtue of inherent tendencies thereto. 'Natural Selection' holds that no such change can take place without the influence of altered external circumstances. 'Derivation' sees among the effects of the innate tendency to change irrespective of altered circumstances, a manifestation of creative power in the variety and beauty of the results; and, in the ultimate forthcoming of a being susceptible of appreciating such beauty, evidence of the preordaining of such relation of power to the appreciation. 'Natural Selection' acknowledges that if ornament or beauty, in itself, should be a purpose in creation, it would be absolutely fatal to it as a hypothesis." “Natural Selection' sees grandeur in the view of life, 16 Vol. iii., p. 808. 17 This is hardly an exact representation of Mr. Darwin's view. On his theory, if a favorable variation happens to arise (the external circumstances remaining the same), it will yet be preserved. |