CHAPTER XXII.

PHYSIOLOGY OF THE SPIRIT.

ALL God's works are according to law-it is His method; and the more we think of it, the more do we see its necessity as a covenant between God and creation. Without law there could be no independent action among the creatures, far less could there be responsibility. It is God who makes the gunpowder explode in the assassin's pistol, and the poison operate in the body of his victim. If He did not do so-if He introduced His own moral perceptions and sovereign will so as to modify or suspend the laws of His administration, the act would be the act no longer of the creature but of the Creator.

Even miracles are according to law, and until we adopt this view of them we never can finally set aside Hume's argument against them. Belief in law is an instinct of our nature, but it is stronger in some men than in others. In some it is so weak as to seek an explanation of all extraordinary phenomena in the sovereign will of the Deity; in others it is so strong as to assert the infinite, eternal, and unchangeable justice of God's physical laws. They are quite prepared to admit the goodness, mercy, and justice of God, but they feel that these must act, not in violation of, but in accordance with law. Such a mind was Hume's. There can be little doubt that in his

celebrated argument he drew his inspiration from a deepseated and instinctive conviction of the inviolability of the physical laws; and that, when he elaborated it into a logical shape, this was the last, and to his own mind, perhaps the least satisfactory form into which he could put it. If Hume had received the definition of a miracle as "the act of a superhuman agent acting according to law," his logic and his instinct would alike have been satisfied. His only difficulty would have been the question of the existence or non-existence of any superhuman agent; but in the settlement of this question logic and instinct would have had no jurisdiction.

It is the duty of science to recover from the domains of mystery to the domain of law all the phenomena of nature, and although its past achievements have been almost entirely confined to things outward and visible, we are warranted in believing that the phenomena of life and intelligence are not less within the pale of its dominion.

To say that spiritual phenomena emerge according to law, is to assert that there is a physiology of the spirit; and although it has not as yet been formally admitted into the list of sciences, it is by no means unlikely that we have already broken ground upon the subject in the recent discoveries of the convertibility and indestructibility of "force "-doctrines most valuable, not so much on account of their own importance, as because of their being the avenue to an entirely new field of research.

What is meant by the convertibility of force is this— light, heat, electricity, magnetism, and momentum (possibly also chemical affinity, gravitation, and elasticity)are all of them different modes or forms of one essential "force." This force can assume any of these forms, and change from one to another without losing its identity.

For example, if we have it in the form of heat, we may change it into light by concentration, or into momentum by the steam-engine. If we have it in the form of electricity, we may change it into light by the electric spark, or into heat by the attenuated wire, or into magnetism by the artificial magnet, or into momentum by the electromagnetic engine. If we have it in the form of momentum, we may change it into light by percussion, or into electricity by the electric machine, or into heat by friction.

What is meant by the indestructibility of force is, that, as it cannot be generated from any source, so neither can it be spent, lost, or destroyed. For example, if it exist in the form of momentum, it can never stop unless it be changed into some of its other forms, such as heat or electricity. If one elastic ball be struck by another of equal weight it will fly off in the same direction, and with the same velocity, after having received its momentum. The other ball which communicated the impulse will be at the same instant put to rest. But, suppose that a leaden ball is shot against a rock, and is thus arrested in its course without communicating motion to the rock which it strikes, the force is not destroyed,-it is converted into heat, and the amount of heat produced will be an exact equivalent of the force expended in producing it.

There is yet one other quality of force which we must notice, and that is, its capability of being stored up in a latent or quiescent state. For example, steam and water contain latent force, and this latent force may be developed as an active force by the steam becoming water, and the water becoming ice. Electricity also may store up force in a latent state by decomposing water. It then resides in the oxygen and hydrogen of which the water was composed, under the form of chemical affinity, and is developed

in the form of light and heat when they are again united in combustion.

But this is not all: the forces which exhibit themselves in the phenomena of inorganic matter are found to be related to the forces which are in action in living organisms. There is, therefore, another convertibility of which force is capable, by which light, heat, and electricity can be converted into another, or living force, possessing perfectly different properties, and in the production of which the original force disappears. This is proved by the fact that the new force may be reconverted into the old; that is to say, light, heat, and electricity may be converted into living force, and living force may be reconverted into light, heat, and electricity.

The ascent which thus takes place in the translation of inorganic into organic force does not end in its vegetable form. The force peculiar to vegetable life undergoes a still further translation into the force peculiar to animal life, and yet the same law operates; there is no generation of force, and there is no destruction of it. All the forces in operation in an animal body were originally light, heat, and electricity, but it was necessary that they should undergo an intermediate change by means of the vegetable kingdom, in order to render them accessible to animal life, because animal life is unable to draw its supplies of vital energy directly from the inorganic kingdom. Vegetables can live on light and heat-animals require the intermediate action of vegetable life to make these forces available for their support.

So far as we have gone, we are guided by observation and experiment; another step in the same direction leads us directly to the physiology of spirit; and if the original force of light and heat ascend by translation, first into

the vegetable kingdom, and after that, by a second translation, into the animal kingdom, we have strong reason to conclude that the forces of spirit life are only a third translation of the original force, and not the generation or creation of a new one.

It has long been an interesting question among scientific men, whether light be a material substance, or no substance at all, all its phenomena being capable of explanation on the hypothesis that it is nothing more than the effect of vibrations, or modulations, communicated to a medium supposed to exist throughout the universe. May it not be that neither of these views is the true one, but that God has created another kind of substance, altogether different from matter, of which light, heat, and electricity are some of the forms-a substance which is as varied and invariable in its properties, and as indestructible in its essence, as matter itself?

It is difficult, indeed, for us to conceive of force being an actual substance distinct from matter; and were it not for its indestructibility, and still more for its being found to exist in a latent or quiescent state, it would not be necessary that we should; but our studies in nature are continually bringing us into contact with new conceptions, the unexpected nature of which fills us at first with curious surprise, but this, after a more mature experience, ripens into reverential admiration. The nature of spirit-phenomena, also, would lead us to anticipate some such discovery as this; and whether it be or not the substance of which spirit is composed (supposing it to have a substantive existence), it cannot differ very widely in its attributes from those which we have described as belonging to "force." In its ascent from its inorganic forms into organic life, where it assumes a quasi