atoms at one end of the molecule rush for the atoms of carbon and hydrogen at the other end, and the molecule is broken up. The combination then is this:

Thus the chemical action was motion, and a pretty forcible motion too, of which any skeptic to his entire and fulsome satisfaction can easily convince himself by experiment. There was a "rush" of atoms, as the learned Professor emphatically expresses himself.

Whatever be the character of the chemical change that takes place, whether a violent or a mild one, it is a law of modern chemistry that no molecular change will take place without an atomic migration, and that every atomic migration is also a molecular change. Consequently all chemical processes which medicine by its doses, big or small, can aim at, is movement. This is very nicely illustrated in the groups of the Potassii-aluminic sulphate (alum), and Ammonia-Alum molecules:

In these two groups the centre Al2 O16 S4 is the same, but the K2 of Alum has been substituted by N2 in Ammonia-Alum,

JOSIAH P. COOKE, Jr., Professor in Harvard, Chemistry, p. 229. (New York, 1876.) The atom of hydrogen and one of nitrogen having been borrowed from the frag. ments of a neighboring molecule.

Cf. COOKE, 1. c., p. 250.

H8 having besides been added, and the whole metamorphosis of Alum into Ammonia-Alum consisted in the migration or interchange of K2 against N2H8.

Likewise, replacing in the nitro-glycerine formula the NO2 atoms by H3 we get

For those, however, who would doubt whether these diagrams of molecular structure are hypotheses, or if not as to their form, yet as to their substance copies from nature, more striking evidences are in store. The discovery of the artificial alizarine which so successfully replaces the more expensive madder-alizarine, was made by a chemist, Graebe, whose arguing, when experimenting, was founded altogether on the molecular structure, according to the type-theory of chemistry, of those bodies that he drew into account. As a body which was derived from naphtalin, and, like many similar derivatives, was reduced back to it when heated with zinc-dust, closely resembled madder-alizarine, in its molecular structure the sagacious chemist was led also to heat madder-alizarine with zinc-dust, when to his surprise, he obtained anthracene.t Now the conclusion was obvious that the same process by which the above-mentioned body was derived from naphtalin, "when applied to anthracene, would yield alizarine. The result fully answered these expectations, and now alizarine is manufactured on a large scale from the anthracene obtained from coal-tar."+

The atoms do not only attract in a peculiar way, but they want to be attracted according to their liking. The eminent French chemist, Ad. Wurtz, speaks of atoms being "animated" and "harmonising," and there are facts which tell in this direction. Although 53,939 volumes alcohol and 49,836 vol

* Cf. COOKE, 1. c., p. 317.

† COOKE, ibid.

COOKE, ibid., p. 325.

§ L. C., p. 247.

umes water sum up arithmetically 103,775 volumes, they enter by being combined, vessels which would not keep more than 100,000 volumes of either, both being kept separately. Thus by being mixed these substances reduce their bulk in the ratio of 9.775 volumes, a reduction which it would be out of the power of any human contrivance to bring about by any mechanical apparatus. It would require a pressure of 800 atmospheres or Ko 1,266,400, not counting the increase of resistance proportionate to increased compression; and consequently it cannot be brought about, except by a voluntary action, as it were, of the alcohol and the water themselves, whose ardent desire to combine by atomic motion sets up a molecular change which increases the material density of the fluid to the extent mentioned above. A similarly surprising chemical action is that palladium takes up 900 times its own bulk of hydrogen, the product being a white metallic solid;* and this law holds good in both the macro- and the micro-cosmos. Ad. Wurtz says: "We have a sound reason for comparing the little world in which atoms are rotating, to the great world in which the stars revolve;"† and although he only brings back this comparison to the fact that "in both all is motion," he cannot help admitting that the biggest worlds are only reiterations of the molecular structure. The law that simple bodies combine in definite proportions is without exception; and accordingly the coercive force which keeps the universe moving in a regular way can as little be located at a central point, as the coercive force which keeps up a nationality can be located in a ruling body in its capital, but must be diffused all through the country. A world can as little as a State keep up its energy by any power which is not its own. An analogy is man in being set down as a cell complex, or a differentiated form of individualised protoplasma. The amoeba not only constitutes his origin, but cell-movement keeps up his life. "The cells devour and march," and rest stamps the blood-cell "with the impress of death." In the depth of the furrow of a nail

* HUGO SDRIFF, in Florentine Lecture.

† Ibid, p. 305.

GREY: Histology, Cutter's transl. p. 12 (New York, 1876). § Id ibid.

"youth prevails; at the upper border which we trim, old age."* In menstruation, science claims that "the lining membrane is generally thrown off cell by cell; the process beginning always just within the internal os, gradually extending to the fundus, and at the same time into the muscular wall;t and Bondrut very acutely puts forward: that motion is not the consequence of the organisation of the human body, but that the organisation of the human body is the consequence of motion.‡

This is a grand idea, indeed, of infinitely more importance to science than the discovery of the rotation of our globe, which in its time frightened so intensely the milites ecclesiæ, whose indifference toward the reversion of philosophical notions in our own time is far less due to their political impotence than to the overwhelming force of these modern statements. There is no help any more against progress.

All-deciding for the dynamic theory is the part that the cell-motion need not any more be concluded from general reasoning; it has been seen, revealed, by the microscope. WallerCohnheims watched even the minutia of the migration of the colorless blood-corpuscles from out of the blood-vessels in case of inflammations, and we may pick out the pathological subjects at random, but it will without any exception be a dynamic relation which comes under survey. Fear and anger even," Broussais says, "doubtless indicate to us the movements that occur in the tissues."

There was a great deal more in the third law of motion of Sir Isaac Newton: "To every action there is always an equal and contrary reaction," than even his most fervent admirers had foreseen. It was a physician, Dr. Mayer, of Heilbronn, "who first raised the idea of the equivalence between heat and mechanical energy to philosophic clearness in his own mind;" and Professor Tyndall, from whose excellent work,

* Id ibid.

†TH. ADDIS EMMET: Principles and Practice of Gynecology, p. 152. (Phil., 1880.

History of the Medical Doctrines, page 476.

§ Cf. WAGNER, (transl. by SEGUIN) Gen. Pathology, p. 250 sequ.

! || Physiology Applied to Pathology, p. 79.

Heat as a Mode of Motion, we cite this sentence,* very judiciously adds: "Those who reflect on vital process, on the changes which occur in the animal body, and the relation of the forces, involved in food, to muscular force, are led naturally to entertain the idea of interdependence between these forces." The Homœopathists and Allopathists may continue to differ about the application or interpretation of the general principle of disease, and of its cure. But they must agree as to the necessity of the law of the conservation of energy by transformation entering into it as its main and most essential constituent. And this point IS THE ONE ABOUT WHICH All SCHOOLS AGREE, indeed. This is demonstrated in the fevertheory," which has always been the mirror of pathological systems," and Wagner in his masterly Historical Sketch of Recent Fever-Theories furnishes ample proof of this development of the medical conviction into the dynamic theory; medicine, or, I should have said, great physicians with their innate gift of intuitive divination foreshadowing natural science, and establishing in a particular sense and application the dynamic theory long before its very trace was extant in abstract learning. Wagner says: "the first results of the application of the new doctrines of physics to the organism, were the propositions which the later mechanists of the seventeenth and eighteenth centuries had advanced; and accordingly their school represents the beginning of Positive Medicine. They abandoned the exclusive regard in which the heat of fever was held, raised the pulse out of the symptom-group, and gradually introduced the movement of the blood into the notion of fever. This was especially brought about by Boerhaven and his school." Even negatively the development of the fever-theory illustrates our general principles of medication; for Cullen's idea of chills being caused by a spasm of the most external blood-vessels sustains in its essentiality the dynamic explanation of all bodily functions. Haller's discovery of the irritability of muscular fibre as a mode of life cleared

*Cf. p. 52.

† WAGNER, by Seguin: Gen. Pathology, p. 648.

Cf. WAGNER, by Seguin, 1. c., p. 685.