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32 more, until finally the machine becomes worthless for the purpose of its construction. If this mechanism possessed the power of adapting from without foreign matter so as to construct it into steel and brass and arrange this just when required, it would imitate a living organism; but this it can not do, nor is its waste chemically different from its component metals; it does not break up brass and steel into something wholly different. In one particular it does closely resemble living things, in that it gradually deteriorates; but the degradation of a living cell is the consequence of an actual change in its component parts, commonly a fatty degeneration. The one is a real transformation, the other mere wear.

Had the watch the power to give rise to a new one like itself by any process, especially a process of division of itself into two parts, we should have a parallel with living forms; but the watch can not even renew its own parts, much less give rise to a second mechanism like itself. Here, then, is a manifest distinction between living and inanimate things.

Suppose further that the watch was so constructed that, after the lapse of a certain time, it underwent a change in its inner machinery and perhaps its outer form, so as to be scarcely recognizable as the same; and that as a result, instead of indicating the hours and minutes of a time-reckoning adapted to the inhabitants of our globe, it indicated time in a wholly different way; that after a series of such transformations it fell to pieces—took the original form of the metals from which it was constructed—we should then have in this succession of events a parallel with the development, decline, and death of living organisms. In another particular our illustration of a watch may serve a useful purpose. Suppose a watch to exist, the works of which are so concealed as to be quite inaccessible to our vision, so that all we know of it is that it has a mechanism which when in action we can hear, and the result of which we perceive in the movements of the hands on the face; we should then be in the exact position in reference to the watch that we now are as regards the molecular movements of protoplasm. On the latter the entire behavior of living matter depends; yet it is absolutely hidden from us.

We know, too, that variations must be produced in the mechanism of time-pieces by temperature, moisture, and other influences of the environment, resulting in altered action. The same, as will be shown in later chapters, occurs in protoplasm.