by our doctrine of the conservation of force, and seems to require the incoming of another element in our calculations. Where does appear the force of mind, the high courage, which can enable a feeble body to maintain a high potential energy out of the same physical materials which contribute to the formation of the sluggishness of others? It may be answered: What makes the difference between the energy of the blooded hunter and that of the dray-horse? Where does the difference appear in the final dissolution? With this latter question we immediately perceive the difference between the degradation of energy which accompanies that which recalls life, and that which is manifested in the combinations of matter. Gunpowder, fired by the concentrated rays of the sun, leaves only ashes and a rapidly-disappearing veil of smoke. It has impressed upon the ether vibrations which are forever undergoing rapid transformations. In regard to its physical nature it goes from inertness to inertness. A current of electricity is maintained by chemical action which takes place in a voltaic cell. As long as this action continues, the current can exercise its functions. When the potential energy of the chemical activity falls, the current dies away. From the earth the gunpowder can be reconstructed with exactly the same characteristics. From the earth beings endowed with life can be created by a process which is far beyond our ken, yet the new creations are never exact reproductions. We are forced to acknowledge that there must be something which is called the principle of life. If there is such a principle, does it die at the physical death of each individual? If so, we must modify the all-embracing scope of the doctrine of the conservation of force and its non-annihilation. When a body loses its heat, or its electrical charge, we can readily form the equation of transformation. With matter endowed with life we must join, by an additive or subtractive sign, an unknown function which we may term the life-function. In discussing such an equation of transformation of energy, we must refuse to admit such a term depending on the life-function, on the ground that we are dealing with matter and material forces, and that there is no energy distinct from that communicated by chemical processes. Or we must admit it; and make some assumption which can just as well be made in reference to its spiritual or non-physical nature as in regard to the peculiar relations which different organic compounds may maintain toward each other. The first step leaves an hiatus in our expression for the transformation of energy, and the second gives a choice of belief.
It may seem to some that the doctrine of Darwin is capable of being extended to intellectual philosophy; and, as certain animal types fail to flourish and perpetuate themselves because the conditions are not propitious, so we can admit the possibility that the South-Sea cannibal is endowed with a mind or soul germ which could be developed if the right conditions were at hand. In chemistry we