Science traces the chain of cause and effect everywhere and finds no break. It follows down animal life till it merges in the vegetable, though it cannot put its finger or its microscope on the point where one ends and the other begins. It finds forms that partake of the characteristics of both. It is reasonable to expect that the vegetable merges into the mineral by the same insensible degrees, and that the one becomes the other without any real discontinuity. The change, if we may call it such, probably takes place in the interior world of matter among the primordial atoms, where only the imagination can penetrate. In that sleep of the ultimate corpuscle, what dreams may come, what miracles may be wrought, what transformations take place! When I try to think of life as a mode of motion in matter, I seem to see the particles in a mystic dance, a whirling maze of motions, the infinitely little people taking hold of hands, changing partners, facing this way and that, doing all sorts of impossible things, like jumping down one another's throats, or occupying one another's bodies, thrilled and vibrating at an inconceivable rate. The theological solution of this problem of life fails more and more to satisfy thinking men of to-day. Living things are natural phenomena, and we feel that they must in some way be an outcome of the natural order. Science is more and more familiarizing our minds with the idea that the universe is a universe, a oneness; that its laws are continuous. We follow the chemistry of it to the farthest stars and there is no serious break or exception; it is all of one stuff. We follow the mechanics of it into the same abysmal depths, and there are no breaks or exceptions. The biology of it we cannot follow beyond our own little corner of the universe; indeed, we have no proof that there is any biology anywhere else. But if there is, it must be similar to our own. There is only one kind of electricity (though two phases of it), only one kind of light and heat, one kind of chemical affinity, in the universe; and hence only one kind of life. Looked at in its relation to the whole, life appears like a transient phenomenon of matter. I will not say accidental; it seems inseparably bound up with the cosmic processes, but, I may say, fugitive, superficial, circumscribed. Life comes and goes; it penetrates but a little way into the earth; it is confined to a certain range of temperature. Beyond a certain degree of cold, on the one hand, it does not appear; and beyond a certain degree of heat, on the other, it is cut off. Without water or moisture, it ceases; and without air, it is not. It has evidently disappeared from the moon, and probably from the inferior planets, and it is doubtful if it has yet appeared on any of the superior planets, save Mars.