everything but taste; there are purple-leaved varieties of the beech and the hazel; and a great multitude of plants sometimes exhibit their leaves cut, blotched, and variegated 1.

Now, from the working of Nature under, as it were, man's guidance, we pass to the working of Nature when left to her own discretion. The work of Natural Selection is a very slow and secret work; the slowness of it veils the movement. As with the hour-hand of a tiny watch travelling but an inch in a day, there is progress which you cannot discern, there is change that can be marked and registered at intervals, though each successive moment and each successive movement seem to leave things exactly as they were. You have heard of the Greek simpleton who had been told that a raven lived three hundred years, and so bought one to see. We might live three thousand years instead of three hundred without being able to prove the theory of Natural Selection by actual observing. But when a group of most important observed facts can be explained consistently by this theory, and by none other, while no fact has been brought forward to make it inadmissible, it ought to be accepted till some theory can be produced equally unimpeachable and explanatory of a larger group of facts.

Qualities are inherited; but with this peculiarity, that very generally, and sometimes of necessity, the inheritor comes into possession of the inherited quality at the same period of life at which it was acquired by the

1 Animals and Plants under Domestication,' vol. ii. pp. 348-351.

parent. As, for instance, the child of a gouty father, though it may be destined in old age to inherit the disease, is not born with the gout, any more than a calf is born with horns, or a cherry-tree produced covered with cherries. In the life of every creature there is not merely growth, but development. At every stage of life it is possible for some quality acquired by variation to be fixed by Natural Selection. But in the embryonic and earliest stages of development, variation is least likely to be of service to any creature. Such variations, therefore, will less often be selected than others, and if it be true that many species have a common ancestry, then it ought to be found that in their embryonic and earliest stages they resemble one another. This is precisely what we do find. Plants, the most remote in appearance and properties when full grown, differ but slightly in their cotyledons: the difference between the egg of a nightingale and the egg of an ostrich bears no proportion to the dissimilarity between the two birds when fully developed; nor by comparing the roe of a herring with the roe of a salmon could you possibly guess, before experience, how the full-grown fish would differ. But in the life of every human being there is a stage of development, at which the most sagacious physician could not distinguish him from the embryo of a snake, a lizard, a bird, or an ape1.

1 An important caution may here be quoted from Mr. Herbert Spencer. An impression,' he says, has been given by those who have popularized the sentiments of Embryologists, that, during its development, each higher organism passes through stages in which it resembles the adult forms of lower organisms-that the embryo of a man is at oxe

Now, if the simplest embryonic forms of life were the progenitors of all existing forms, this is intelligible; but how else can it be explained?

But, again, if species do not vary, how comes it that those living at the present day are for the most part not to be found among the fossil creatures of the ancient rocks? Well, some will tell you there have been many distinct creations, following after many catastrophes potent to destroy all the previous inhabitants of the globe. Well, I will answer, if you rest on Scripture, that view has no basis in Scripture, but if you do not rest on Scripture, it certainly has no scientific foundation, for though the crust of the globe has been made what it is almost exclusively by the action of fire and water, the effect of any sudden convulsions has been a mere nothing as compared with the results from the steady, slow-going, ceaselessly-operating forces of those two agents. Besides, when you look back through the rocks of different ages, not only do you find some forms the same in all, which testifies to the permanent unity of the living creation, but in those forms which differ, you find the differences increasing the further you go back, and some forms you find which have no modern representatives, forms, that is, which have been beaten in the struggle for existence.

time like a fish, and at another time like a reptile. This is not the fact. The fact established is, that up to a certain point the embryos of a man and a fish continue similar, and that then differences begin to appear and increase the one embryo approaching more and more towards the form of a fish; the other diverging from it more and more. with the resemblances to the more advanced types.'-Principles of Biology, vol. i. p. 143.

And so

Travel over the globe, and every country will present you with some new species; distant rivers, distant islands, in the ocean shallows separated by great deeps, the opposite sides of a continent, the twin sides of a mountain chain, the foot, the spur, the knee, the breast, the snow-clad head of an Alpine range, will all present you with their own peculiar forms of life. And how came they there? Created, some will say, in those regions and for those regions, because of their special adaptation to them. Yet, since the globe has been inhabited, vast tracts of it have changed their climates from tropical heat to frozen gloom, and again, yielded the thick-ribbed ice to genial suns and fragrant zephyrs. Unhappy species, the creatures of a fixed idea, created for the temperate meridian of Devonshire, and condemned by the thoughtlessness of nature, to pass their lives in a climate like that of Nova Zembla!

But further, had each species been assigned to its station as some suppose, by a single act of creation, is it not reasonable, does not reverence require us to expect, that each species would have been best off in its own station? But this is not the case. On the contrary, imported species of plants and animals often thrive prodigiously in their new habitat, and over-run it.

Once more, we find in numberless plants and animals rudimentary organs that are of no use to the possessors, -mammæ, that give no milk; pistils, in male florets; in insects wings too small for flight, and soldered to the wing cases; the fifth toe in the hind-foot of the dog; the spur of the hen; the wing of the Apteryx; and the

stunted, ineffectual, but ever-present tail in our noble selves.

On the old theory of creation, in face of these facts, we cannot save the admired doctrine that nature does nothing in vain; but on the Darwinian theory of creation, that doctrine still holds good, and wisdom is still justified by all her productions; for Natural Selection works only for the good of a species; it does not work in vain, or waste its efforts in getting rid of any organ simply because it is useless, so long as it is not injurious; it leaves it as it was and where it was, a germ, a capacity, perhaps, in the future, to be re-developed or fitted for a new purpose.

Here we have incidentally touched upon what seems to be morally the grandest part of the whole theory, an even sublime explanation, as far as it goes, of that small fraction which we see in terrestrial life of the great and manifold works of God. We noted above that it is to death, a necessity much hated, much maligned, that we owe the possibility of our own birth and standing-room on the face of the globe; but the theory of Natural Selection makes it further clear that the causes of death which we most dread and think evil of-war and famine and pestilence-are tending continually to improve the races of living creatures. On the whole, the wisest, the strongest, the healthiest survive to propagate their species. In the long run, prudence, courage, and temperance prevail, and their owners become the parents of the later generations.

When the competition for life becomes severe, as to