PREFACE.

In a work lately published under the title of "Proteus; or, the Law of Nature," I have endeavoured to realize that unity, or rò èv, which is said to ensoul the diversities of things, and bind them together in one. I have traced this principle in plant and animal, not merely as a vague generality, but as pervading the entire structure-from a simple organ to a perfect organism, and from the complicated nervous, vascular, or osseous systems, to the more rudimentary parts of the economy. I have traced, also, the same principle into inorganic bodies;-so that in relation to form, we may conclude that there is one archetypal law in all created things, whether animate or inanimate. Heat, light, chemical affinity, electricity, motion, and other physical agencies, have also been found to be connected with each other, and with the more recondite vital influences, as correlative aspects of one central force; so that the unity of creation is reflected in force as well as form. And finally, this principle

has seemed to be absolute, for on proceeding onwards it is seen to be impossible to separate form from force, and to regard the one as a mere lifeless image, or the other as a mere (( naked essence."

But it may be objected that all these ideas are mere philosophical abstractions, and that this unity of nature is not a practical truth to be realized in the problems of every-day physiology. If there be this oneness of which you speak, it may be asked, how is it that the body is obedient to a law which is totally different to anything we find in inorganic nature? Will it explain the hitherto inexplicable capillary movements of the blood?-will it solve the oftperplexed, and still unread riddle of muscular action? -will it tell us why the heart continues its mysterious beatings?—will it give the clue to a hundred acts and movements which are distinctive of life, and which we are obliged to refer to an incomprehensible and potent essence which is shut up in every living body?—for, except it will help to do these things, the doctrine is of no practical value. An objection like this is just and right, for no one can be expected to receive an opinion which is based merely on transcendental facts and arguments, especially when it is belied (or seems to be) by his own daily experience.

Let us encounter, then, this objection on the grounds that are here indicated, and inquire whether the phenomena of vital motion will not receive light and interpretation from the doctrine they seem to contradict. Remembering the arguments for a common law, let us not seek the explanation in the body alone in which the movements are manifested, but in a wider range of causes. Let us treat unity as a reality and not as a fiction, and wait patiently for the result. If we do this, every phenomenon will be found to point to this truth; and this truth, on the other hand, by enlarging our ideas to receive the comprehensiveness of nature, will enable us to advance far towards the explanation of vital motion. If we do this, the movements of blood or other nutrient fluids in vessels independently of any cardiac impulse, the action of muscle, the beating of the heart, and many other mysteries of life, will no longer perplex us, for each will interpret the other, and all will refer to a common law-cosmical-one.

4, Henrietta-street, Cavendish-square.

January 1st, 1851.

THE

PHILOSOPHY OF VITAL MOTION.

CHAPTER I.

PRELIMINARY CONSIDERATIONS RESPECTING VITAL MOTION.

In spring the seed of the sensitive plant becomes the seat of active life, and the sapling emerges from the shelter in which it had slept during the cold season; in summer the foliage is unfolded; in autumn the verdure and freshness are lost; and in winter the plant is bare and dead. At the return of spring the buds receive new life and awake from their dormant condition; in summer the branches are reclothed with leaves and blossoms; in autumn the vital energies decline; and in winter the plant is again reduced to a naked and lifeless skeleton. Year by year these phenomena succeed each other in the same order and with the same regularity, so that the vitality would seem to ebb and flow in direct relation to the varying intensity of the sunbeams. At daybreak, also, the

B