holtz with the aid of the mechanical theory of heat, leads to a conception of the origin of our planetary system. We first see our earth revolving in its orbit as a glowing fluid drop with an atmosphere of undefinable constitution. In the course of immeasurable intervals of time we see it become coated over with a crust of indurating primordial rock; sea and land are divided, eruptions of hot carbonic acid break up the granite, and give material for strata of alkaline earths, and finally the conditions arise under which life became possible.
Where and under what form life first appeared, whether at the bottom of the deep sea, as bathybius protoplasm, or whether with the cooperation of the still excessive ultra-violet solar rays, with still higher pressure of carbonic acid in the atmosphere, who can tell? But Laplace's Mind could tell, with the aid of the universal formula. For, when inorganic matter coalesces to form organic matter, there is only a question of motion, of the arrangement of molecules into states of more or less stable equilibrium, and of an exchange of matter produced partly by the tension of the molecules, and partly by motion from without. What distinguishes living from dead matter, the plant and the animal, as considered only in its bodily functions, from the crystal, is just this: in the crystal the matter is in stable equilibrium, while a stream of matter pours through the organic being, and its matter is in a state of more or less perfect dynamic, the balance being now positive, again approaching zero, and again negative. Hence, without the interference of extraneous masses and forces, the crystal will remain forever what it is, whereas the organic being depends for its existence on certain exterior conditions, transforms potential into kinetic energy, and vice versa, and has a definite duration in time. Thus we see, that though there is no fundamental difference between the forces operating in the crystal and in the organized being, still the two are incommensurable, just as a simple building is incommensurable with a factory into which coal, water, and raw material pass, on this side, while at the other side carbonic acid, water, vapor, smoke, ashes, and the products of the machinery, are sent out. The building we may regard as so made up of parts, each resembling the total result, that, like the crystal, it is separable into like parts; the factory, like the organic being (if we abstract from the cellular constitution of the latter, and the divisibility of sundry organisms), is an Individual.
It is therefore an error to recognize, in the first appearance of living things on the earth, any thing supernatural, or any thing else save an exceedingly difficult mechanical problem. This is one of the two errors toI proposed to call attention. The other limit of natural science is not here, any more than in the fact of crystallization. Were we able to create the conditions under which organic beings had their rise, which we are not even able to do for all crystals, then, according to the principle of actualism, we could produce organic