ent property of the living substance. Do we as yet comprehend in the same way the intimate modes of activity which constitute the properties appertaining to inorganic substances? Is any kind of those peculiar motions which form the scientific essence of the various forces of inorganic Nature so strictly and deeply intelligible as has now become that specific motion which forms the scientific essence of the force of life?
Motion of any kind stands at present just in the same relation to dead matter as that special mode of motion called contractility stood, before this, to living matter. Mechanical motion, heat, electricity, etc., are all qualities occultisimal, known only by the relative measurement of the spaces of contraction and expansion which their manifesting substrata occupy, or are thought to occupy.
Comparative expansion and contraction are, and must be, the subject matter of all quantitative science. All intensities are made quantitatively scientific by being "converted" into modes of space. Time itself is thus measured, and the intensity of heat can be ascertained only by the expansion and contraction of the manifesting substances. So with all. Our undulatory theories are expressions of the same helpful makeshift; an expanding and contracting substratum.
Motility is precisely such another expansion and contraction. But, now, we know not merely the fact. We know, besides, how it is effected. We know something about the working of it within the manifesting substance. By this qualitative penetration, this more substantial insight into natural operations, we have broken the consolidated crust of mere superficial shiftings in space, and have forced a scientific entry into deeper spheres of knowledge.
The comparisons between motility and other modes of motion are strictly appropriate. How much so cannot be adequately appreciated until the origin and development of sensation have been traced; of which all modes of motion are, in the last instance, accurately corresponding affections or reactions.
And, now, what has become of this most vexed problem of problems—the origin of life? Is not protoplasm a chemical compound like other substances, merely varying from them in its degree of molecular complexity? Its most characteristic manifestation, its distinguishing mode of motion, its peculiar force—the one specific activity constituting its most vital difference—is better known to us than any quality which forms the distinguishing feature between other substances. Do we greatly concern ourselves about the origin of MgO,SO3+7H2O, or any other mineral substance? Why, then, should the origin of some combination of C, H, N, O, be made a question of the life and death of our principal philosophies? Has it actually come to this, that the scientific foundation of our creed rests on the decision whether COO is or was once changed into CHO by natural or supernatural means; and this when there is plenty of H about in our world? Yes, it is even so,