To raise a weight from the ground, to make water run up-hill, or to generate heat by friction, are all processes which require the expenditure of effort and material substance, if we would perform them ourselves. So in Nature, this form of synthesis is never accomplished without the expenditure of energy from some source. In the vegetable, the power comes directly from the sun, and the world in summer is colder and less brilliant (by an infinitesimal amount, it is true), because of that growth of leaves and wood which in the winter we reconvert into heat and light in our stoves; the animal gets the force for its synthesis by eating and consuming the products of vegetable life; and the chemist in his laboratory obtains his power mainly by converting a large amount of some complex body into simpler ones, in order to raise a smaller portion of some other mass to a more loosely aggregated and heterogeneous condition.
Starting with the elements and simple mineral bodies, the construction of such substances as salts, by the union of an acid and a base; of a suffocating gas, by the combustion of sulphur; of the conversion of iron into rust, by the action of water, air, etc., is very easy up to a certain point—so easy, that probably the very earliest beginnings of chemistry lay in observations of these facts. Certainly, the historic origin of the science in alchemy leaves no doubt of it as regards the middle ages, and, at the present day, most of the technical applications of the science are examples of the building up of compounds. So long as the experimenter's efforts were confined to mineral matter, he met with but little trouble; but, the moment he tried to reproduce any organic body, any compound which was the direct product of life, either animal or vegetable, he met a barrier which seemed to be insurmountable, and which bade fair never to be crossed. It was easy enough to analyze any of these vital products, and to determine the exact number and amount of their ingredients; but, once separated, the chemist vainly endeavored to make the elements reunite as they were before.
This was the state of things up to forty or fifty years ago. The power of the chemist had grown to be very great; he could either bind or loose, as pleased him, and he thought be had a tolerably complete knowledge of the elements and forces he was dealing with. Is it so much wonder, then, that he fell back on the assumption of the existence of a mysterious force outside of his domain, and that his defeat, coupled with the known impossibility of restoring life to the dead animal, should have led to the assumption that these organic bodies were the result of chemical processes which had been aided and controlled by a special entity, denominated vital force?
It is not the object of this paper to take sides on a question which is still a matter of debate; and, in regard to vital force, it has only to chronicle here some of the steps by which bodies, hitherto solely evolved by the action of living matter, may now, under the guidance
