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Agnosticism.

VII.

EVOLUTION OF LIFE.

WE

E are engaged in considering to what extent, and in what manner, our knowledge of God is affected by the discoveries and theories of modern science. In taking a brief preliminary survey of these discoveries and theories, we have seen it must now be considered proved, that the different species of plants and animals, instead of being separately created, were derived partly, at any rate, under the influence of natural selection-from a few primordial forms. And further, we have seen there are reasons— strong, though not perhaps amounting to demonstration for supposing that the entire animal and vegetable world has been developed from a single primary living object. Now the question

arises, Was that first living object a direct creation? or may life itself be an evolution from non-living matter?

Darwin assumed that the primordial form, or forms, had been directly called into existence by the Creator. But his followers have not been content to stop here. They have endeavoured to push the doctrine of evolution farther, and to make it account for the origin of life itself. An ingenious theory was started some time ago by Sir William Thomson, to the effect that the germs of life had been brought to our planet upon the meteoric stones, which came from distant parts of space. It is manifest, however, that this theory only postpones the difficulty. Sooner or later we must face the question, Whence came the first life? And before we can answer it, we must inquire whether there is any distinctive differenceand if so, what-between animate and inanimate objects.

Till quite recently it would have been said that they differed unmistakably from each other by the presence, or absence, of organisation. Animate bodies, it would have been said, are always composite in their structure, consisting of dissimilar, heterogeneous parts, which serve

as organs or instruments, and work together for the discharge of a variety of functions. On the other hand, the most perfect anorgana-viz., crystals consist entirely of homogeneous matter, and their structure is not composite but simple. But this distinction has broken down since Haeckel's discovery of monera. You remember I pointed out to you, that the gulf between the animal and vegetable worlds seemed to have been bridged over by the Protista-living creatures that possess the essential characteristics of both worlds. Among these Protista, Haeckel has discovered some objects which he calls monera, and which would seem, in a similar manner, to bridge over the gulf between the organic world and the inorganic. For these monera are, as he says, "organisms without organs." They are without organs, inasmuch as their whole body consists only of a single, perfectly homogeneous lump of protoplasmic slime, in which the strongest microscope can detect no distinction of structure. And yet they are organisms, inasmuch as they go through all the functions of life. They wriggle about in the sprightliest manner. They project and withdraw little filaments like arms and legs. They feed upon atoms which accidentally become imbedded in their surface. And

when they have outgrown their normal size, they reproduce themselves by splitting up into two. The possession, then, of what are properly called organs, would no longer seem to be essential to life.

And not only are we unable to distinguish by internal organism the living world from the nonliving; we are equally incapable of distinguishing it by its external form. The forms of crystals, it is true, are mathematically determinable, limited by plane surfaces which meet in straight lines at certain measurable angles. Vegetable and animal forms, on the contrary, do not, as a rule, admit of such geometrical determination. They are, for the most part, limited by curved surfaces and crooked lines meeting at variable angles. But recently, among the lower organisms, large numbers of living creatures have been discovered, whose forms are bounded, just like those of crystals, by definite, geometrically determined planes and angles. And there are also perfectly amorphous organisms-viz., the monera and amœbæ—which change their forms every moment, and in which we are as little able to point out the definite, fundamental form, as in the case of stones or deposits of mud. We cannot, then, find any essential difference, either in the

external form or in the internal structure, of animate and inanimate bodies.

But it may be said, notwithstanding this fact, that the functions and processes of life are infinitely more mysterious and wonderful than anything which takes place in the inorganic world, and must be attributed to some non - material principle (call it vital force, or what you please) — a principle quite distinct from any of the chemical forces which it takes into its service. But are organic phenomena so much more mysterious and wonderful than inorganic? When we compare the growth of a crystal with the growth of a living creature, we find a remarkable similarity between the two processes. If saltpetre is dissolved in boil

ing water, and the water allowed to cool, after a time little bodies, like delicate needles, are observed darting about in all directions, and gradually joining one another in certain definite and regular ways. By dissolving the saltpetre, we have divided it into minute invisible particles. But as the water cools, their mutual attraction draws them together, and they unite, not into mere shapeless lumps, but each little molecule, as it joins the rest, places itself in the proper position to help in building up the beautiful sym