When we regard all the phenomena of life and the spell it seems to put upon inert matter, so that it behaves so differently from the same matter before it is drawn into the life circuit, when we see how it lifts up a world of dead particles out of the soil against gravity into trees and animals; how it changes the face of the earth; how it comes and goes while matter stays; how it defies chemistry and physics to evoke it from the non-living; how its departure, or cessation, lets the matter fall back to the inorganic--when we consider these and others like them, we seem compelled to think of life as something, some force or principle in itself, as M. Bergson and Sir Oliver Lodge do, existing apart from the matter it animates. Sir Oliver Lodge, famous physicist that he is, yet has a vein of mysticism and idealism in him which sometimes makes him recoil from the hard-and-fast interpretations of natural phenomena by physical science. Like M. Bergson, he sees in life some tendency or impetus which arose in matter at a definite time and place, "and which has continued to interact with and incarnate itself in matter ever since." If a living body is a machine, then we behold a new kind of machine with new kinds of mechanical principles--a machine that repairs itself, that reproduces itself, a clock that winds itself up, an engine that stokes itself, a gun that aims itself, a machine that divides and makes two, two unite and make four, a million or more unite and make a man or a tree--a machine that is nine tenths water, a machine that feeds on other machines, a machine that grows stronger with use; in fact, a machine that does all sorts of unmechanical things and that no known combination of mechanical and chemical principles can reproduce--a vital machine. The idea of the vital as something different from and opposed to the mechanical must come in. Something had to be added to the mechanical and chemical to make the vital. Spencer explains in terms of physics why an ox is larger than the sheep, but he throws no light upon the subject of the individuality of these animals--what it is that makes an ox an ox or a sheep a sheep. These animals are built up out of the same elements by the same processes, and they may both have had the same stem form in remote biologic time. If so, what made them diverge and develop into such totally different forms? After the living body is once launched many, if not all, of its operations and economies can be explained on principles of mechanics and chemistry, but the something that avails itself of these principles and develops an ox in the one case and a sheep in the other--what of that? Spencer is forced into using the terms "amount of vital capital." How much more of it some men, some animals, some plants have than others! What is it? What did Spencer mean by it? This capital augments from youth to manhood, and then after a short or long state of equilibrium slowly declines to the vanishing-point.