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are correlated?

One

Does this even

Does the word excite mean to convert? force rouses or excites another force to action. suggest conversion? Yet this is all Professor Youmans's case amounts to. Second. But if this be so, what force has the expression "in the same manner," which is intended to transfer the presumption gained on one side to the other? But if it is not proved that nerve and muscular forces are correlated, then it is not proved that will power and nerve force are―since this case borrows from that its title to favor. Besides this, as we have already seen, though it might be shown that nerve and muscular forces are mutually convertible, even a presumption could not be gained in this way in favor of the conversion of nerve force into will force, unless it can be shown, as it never has been, that nerve force is vital force.

Again, "Vitality would not then be a special principle, but a result, and would be explained ultimately by the operation of molecular forces."-Maudsley, Body and Mind. This is simply the reiteration of an assertion, made in almost numberless ways, that "vitality" or vital force is a mere compound. or collocation of physical forces. But we have already seen on what kind of real foundation such assertions rest. While the conclusion is thrust prominently forward and used as if it was a real datum, we are told its premises will be ultimately produced. Until they are produced, what have we besides mere assertion?

Again, "The plant apparently seizes the combined carbon and oxygen, tears them asunder, storing up the carbon and letting the oxygen go free. By no special force different from other forces (physical forces) do plants exercise this power—the real magician is the sun!"-Heat as a Mode of Motion, p. 445. Here a qualitative equality is asserted as between the assimilative force of plants and physical and chemical forces. But what foundation have such confident assertions? The proof of this is, that "without the sun the reduction [of carbonic acid] cannot take place." Of course. But what is this more than to say, that without the spark there could have been no explosion? But we shall soon meet with another statement from Professor Tyndall, the bare mention of which will render any further examination of this unnecessary.

In like manner we might fill page after page with mere

assertions, in which the comment would have to be "highly important, if true," but which, in most cases, would be found destitute of any real foundation. But alongside of the assertions, specimens of which have been quoted, it is but fair to state that most of the men who have made them have admitted, directly or indirectly, the proof of the correlation of physical, vital, and mental forces is not so clear and satisfactory after all. It is with most, at times, pretty much as it is with Professor Huxley when he says: "I hold, with the materialist, that the human body, like all living bodies, is a machine, all the operations of which will sooner or later be explained on physical principles." It has not yet been done, but will be some day. The difficulty of the case is conceded or expressed in numberless passages like the following:

Knowledge cannot pass the life boundary.-Maudsley. Subtle influences.-Huxley. Under sundry circumstances.-Ibid. Mysterious agency.-Barker. Suppose a case, [and then following this, and depending on it:] Now an evident corollary from this conclusion or formula, etc.-Spencer. Singular inward laboratory.— Huxley. We may hope that future investigations will throw more light on this subject.-Büchner. We doubt not. Chemistry doubts not her ability. We may still hope. It may be expected. Future investigations will decide. Might at some period have commenced. Presupposing a first organic, etc. We can only imagine. Happened under unusual conditions. Chemistry has not succeeded in forming a Wastema, nor physics in forming a cell.- Virchow. May some day, etc. - Virchow. Natural effects as yet unknown to us in their relations.-Büchner. With all our knowledge we skim only at the surface of life.--Ibid. Life in its inmost relations is certainly a book with seven seals-riddle upon riddle.—Ibid. I believe that we shall sooner or later arrive at a mechanical equivalent of consciousness, just as we have arrived at a mechanical equivalent of heat.-Huxley, Lay Sermons, p. 339.

He believes it. If so, he believes on evidence. "Belief," says Professor Huxley, "in the scientific sense of the word, is a serious matter, and needs strong foundations. . . . But expectation is permissible where belief is not." Now, what are the "strong foundations" on which the "scientific" belief, above avowed, rests? If we are not mistaken, we have succeeded in showing, that so far from such "belief" having "strong foundations," there is no real foundation whatever.

The cases we we are about to cite might have been placed under the head of analogies, but they better deserve the place we have made for them. We class them under the head of imaginary analogies-not real ones-or, better still, as imaginings.

The first case shall be from Mr. Spencer's "Psychology," in his chapter on the Genesis of Nerves. This case is not taken because it is the only one his writings furnish. We really had some difficulty in deciding as between this and other cases as to which we should take. But let the reader give attention to the following account of the formation of

nerves.

Says this ingenious writer:

When through undifferentiated tissue there has passed for the first time a wave of disturbance from some place where molecular motion is liberated, to some place where it is absorbed, the line of least resistance followed must be an indefinite and irregular one. Fully to understand the genesis of nerves we must understand the physical actions which change this vague course into a definite channel, that becomes ever more permeable as it is more used. . . . To aid our conceptions we will, as before, take the rude analogy furnished by a row of bricks on end, which overthrow one another in succession. If such bricks on end have been adjusted so that their faces are all at right angles to the line of the series, the change will be propagated along them with the least hinderance, or, under certain conditions, with the greatest multiplication of the original impulse. For when so placed the impact each brick gives to the next, being exactly in the line of the series, will be wholly effective, but when they are otherwise placed it will not. If the bricks stand with their faces variously askew, each in falling will have a motion more or less diverging from the line of the series; and hence, only a part of its momentum will impel the next in the required direction. Now, though in the case of a series of molecules, the action can be by no means so simple, yet the same principle holds. The isomeric change of a molecule must diffuse a wave which is greater in some one direction than all others. If so, there are certain relative positions of molecules, such that each will receive the greatest amount of this wave from its predecessor, and will so receive it as most readily to produce a like change in itself. A series of molecules thus placed must stand in symmetrical relations to one another-polar relations as it is not difficult to see that, as in the case of the bricks, any deviation from symmetrical or polar relations will involve a proportionate deduction from the efficiency of the shock, and a diminution in the quantity of the molecular motion given out at the far end. But now, what is the indirect result when a

wave of change passes along a line of molecules thus unsymmetrically placed? The indirect result is, that the motion which is not passed on by the unsymmetrically arranged molecules, goes toward placing them symmetrically. Let us again consider what happens with our row of bricks. When one of these in falling comes against the next standing askew, its impact is given to the nearest angle of this next, and tends to give this next a motion round its axis. Farther, when the next thus moved delivers its motion to its successor, it does this not through the angle on the side that was struck, but through the diagonally opposite angle, and, consequently, the reaction of its impact on its successor adds to the rotary motion already received. Hence the amount of force which it does not pass on, is the amount of force absorbed in turning it toward parallelism with its neighbors. Similarly with the molecules. Each in falling into its isomeric attitude, and passing on the shock to its successor, stands in polar relation toward it, but which, if the relation is not polar, is only partially passed on-some of it being taken up in moving the successor toward polar relation. One more consequence is to be observed, Every approach of the molecular toward symmetrical arrangement increases the amount of molecular motion transferred from one end of the series to the other. Suppose that the row of bricks, which were at first very much out of parallelism, have fallen, and that part of the motion given by each to the next has gone toward bringing their faces nearer to parallelism; and suppose, that without further changing their positions of bases, the bricks are severally restored to their vertical attitudes, then it will happen that if the serial overthrow of them is repeated, the actions, though the same as before in their kind, will not be the same as before in their degrees. Each brick, falling as it now does more in the line of the series, will deliver more of its momentum to the next, and less momentum will be taken up in moving the next toward parallelism with its neighbors. If, then, the analogy holds, it must happen that in the series of isomerically changing molecules, each transmitted wave of molecular motion is expended, partly in so altering the molecular attitude so as to render the series more permeable to future waves, and partly in setting up changes at the end of the series; that in proportion as less of it is absorbed in working this structural change, more of it is delivered at the far end, and greater effect produced there; and that the final state is one in which the initial wave of molecular motion is transmitted without deduction, or rather without the addition of the molecular motion given out by the successive molecules of the series in their isomeric falls.

From beginning to end, therefore, the development of nerve results from the passage of motion along the line of least resistance, and the reduction of it to a line of less and less resistance continually. The first opening of a route along which equilibrium is restored between a place where molecular motion is in excess and a place where it is in defect, comes within this formula. The

production of a more continuous line of that peculiar "colloid" best fitted to transmit the molecular motion also comes within this formula, as does likewise the making of this line thicker and more even. And the formula also covers that final process by which the line, having been formed, has its molecules brought into the polar order which least resists, and indeed facilitates, the transmission of the wave. . . . Each approach toward an attitude of equilibrium is a change toward diminished resistance; and so on, until there are simultaneously reached the state of structural equilibrium and no resistance. Carrying with us these conceptions, we now pass from the genesis of nerves to the genesis of nervous systems.-Paragraphs 224, 225.

We may remark that the account of the genesis of nervous systems is equally luminous and satisfactory. After you leave his chapters on the "unknowable" in his "First Principles," Mr. Spencer's mode of proceeding through biology and psychology is fairly represented by this extract. When soberly regarded, can any one say they have ever met with a more fanciful, or artificial, or minute account of a process, the details of which are mostly beyond the power of the microscope, and of which, for this reason as well as for others, we know almost nothing? Mr. Spencer has no trouble whatever in furnishing himself with an obedient "colloid." He then assumes imaginary motions springing up here and there, apart from any apparent cause, and then directs these imaginary "motions along purely imaginary "lines of least resistance," knocking down imaginary "rows of bricks," "askew" and otherwise, or anywise, and picking these "bricks" up again and again, and as often knocking them down until they cease to be "askew," and then ends with them, whether down or up we know not. But at this point "bricks" and "molecules" disappear in their "lines" and "series," and, a path having been established in his "colloid," a nerve emerges, as from a dissolving view, as the highway of "motions," nervous and mental, for the future.

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Mr. Spencer is a believer in the "correlation of the physical, vital, and mental forces," and, moreover, is a believer in the doctrine of evolution "from the homogeneous to the heterogeneous," from the "simple chemical elements" to the "colloid," and from the "colloid" to all "differentiated" tissues of the animal body-from the simple "chemical and physical forces" up to "life," and from "life" to "mind." In these two parallel series the terms are so related that the one above FOURTH SERIES, VOL. XXIV.—28

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