perform the operation, whilst the plant does it without the latter, and at a far lower temperature. If we borrow from the plant and use diastase from malt, or from the animal, and employ saliva, we may, indeed, produce the change under the conditions in which the plant or the animal can, but these fermentations are another mystery, and chemistry knows nothing of the manufacture of the ferment. In all these actions, which we can in some sort imitate, chemical force is exerted on formed and dead compounds. It can oxidize and destroy effete matters in the organism, but in the building up of structure, and assimilation of nutriment, we stand in the presence of some directing and controlling power which uses chemical force as a servant, but which can in no way be confounded with it. So man can utilise this force; he can accomplish with it wonders which may not unnaturally excite visionary hopes of dispensing with the aid of nature; but it is the directing mind and hand which bring about these marvels. Chemical force in itself tends to equilibrium and rest. Complex compounds are in a state of unstable equilibrium, and tend to dissolution. They are subject to resolution into more stable, because more simple, compounds, and if this were all, the final result would be death and silence. According to the teaching of modern science, there was a time when the materials of the earth were in a state of intensely heated vapour; as this cooled, simple compounds, as carbonic acid and water, silica, and the oxides of the metals, would be formed. But these are also the most stable and unchangeable compounds, and whence came the tendency to complexity and consequent instability, with life as the crowning point of the edifice. We have not the faintest knowledge of anything in chemistry that can do this. Man, with the inherited wisdom of ages, and every resource in the way of apparatus, and materials manufactured for him in the laboratory of nature, has hitherto not even approached the preparation of

what has been called the physicial basis of life. He cannot even find out its true composition, and although the simplest living matter is a complex union of albumenoids, fat, and mineral substances, as shown by analysis, we do not even know whether these may not be nothing but the products into which the living mass resolves itself when it dies. Yet this mass of organic complexity, comprising six or eight elements, or even more, if the mineral constituents are all essential, which, without life, tends to instant dissolution, we are bidden to assume at some unknown time, and under some unknown and, I suppose, unreplaceable conditions, did manage to get formed and forthwith live. It may be so, but chemical force must not be invoked as the agent, for it knows nothing of it. Under the direction of mind, chemical force can work wonders. It has already won triumphs in the manufacture of colouring materials which rival, or even excel, those of nature in brilliancy, and now it is learning to make the finished products of nature. Alizarine, the colouring matter of the madder, and indigo, the product of several different plants, have both been manufactured, and although the latter is still dearer than the natural product, it is presented in a form in which it can be profitably used. It must not be forgotten that every chemical substance of this nature derived from the animal or vegetable kingdom, which has hitherto also been produced artificially, is only an organic substance, in that it was naturally produced by an organism. It was not a living part of that organism, but a product of it, either like urea, a waste material, the final result of the wear of nitrogenous parts of the body, or like conine, an active principal medicinally, but, so far as we know, fulfilling no useful or at least necessary part in the hemlock plant. There is no reason, however, for putting any limit to the result of chemical work in this direction. Every definite chemical substance whose composition can be expressed in a chemical

formula, stands forth to be imitated, or rather reproduced, by the art of man. Nor do I think that man is wise who puts any limits as to what may or may not be attempted. It is as rash to say beforehand that a thing cannot be done, as to say that it can. The doing of it is the only proof that the thing is possible, and the only refutation of the charge that it is impossible. But there is little need at present to take down barriers; one has only to read the newspapers to see that those, at least, who know very little of the subject, be it chemistry, electricity, or any other force which has just received a novel application, have the most liberal expectation of the wonders which loom before them, and I fear must feel disappointed that the realisation of their dreams is not forth with brought about.

In this review of our knowledge of chemical force, I fear that you may feel disappointed at the negative character of the result. I have no new idol to set up for worship, in lieu of the old ones; no new theory of the cause of the rush of atoms and their mutal cohesion to offer. Lucretius might be excused for endowing his atoms with mechanical means of fastening themselves together, such as hooks and spikes, and having set his atoms aimlessly falling through space, accounting for the formation of compounds by the atoms becoming entangled with one another. Those with many hooks thus gave hard and solid compounds, whilst those which were comparatively smooth cohered but slightly, so as to form liquids or gases. In those days theory was rampant; experimental philosophy was comparatively unknown; if things were in some way accounted. for, not absolutely absurd, all was well. But there is something from which the human mind revolts in the formation of a universe, with its nice adaptations, and the numberless arrangements for use and beauty in the

undirected and fortuitous concourse of atoms. We cannot

believe that

"For blindly, blindly and without design,

Did these first atoms their first meetings try;
No ordering thought was there, no will divine

To guide them; but through infinite time gone by,
Tossed and tormented, they essayed to join,

And clashed through the void space tempestuously,
Until at last that certain whirl began,

Which slowly formed the earth, and heaven, and man.

There is mystery here as in all the phenomena of nature. In the simplest chemical reactions there is much that we cannot understand. The old philosopher, Kanada, knew as much as we, and adrishta, the Unseen, is still the best name we can give to the chemical force. There is no reason why we should not investigate the secrets of nature, and push our researches into the domains of the unknown. We may be sure that no earnest and sincere work can fail of some reward, and that as the ages roll on more light will illumine recesses of the temple of nature at present dark and impenetrable by human vision. But our attitude should be modest and reverent, and nothing must be received as articles of scientific faith to be accepted under penalty of scientific excommunication. Science means knowledge, not faith, and, short of actual demonstration, the mind must be held free to receive new truth, however opposed to old prepossessions. When we cannot fully explain all that is involved in the formation of a drop of water, I think we ought not to dogmatise on the profound mysteries of life and sensation, and when the action of a single force is fully understood, it will be quite soon enough to speculate on what would be the result of the combination of it with known, or even yet unknown, forces.

Mallock's, Lucretius.