find here a farther verification of the hypothesis. Blood being needful for the performance of function, and the activity of function being, other things equal, proportionate to the supply of blood, it naturally happens that a con- tinuance of the supply after the demand for function has ceased, causes undue readiness to resume function. When, among the data of psychology, WQ dealt with relations between blood and nervous action and feeling, we saw that an excess of blood at the periphery of the nervous system, as in an inflamed part of the skin, is accompanied by ex- treme sensitiveness: the molecular change then set up in the disturbed end of a nerve, is so great as to send an unduly powerful discharge to the point where feeling is aroused. If we transfer these conditions from periphery to centre, we at once see how this abnormal genesis of ideas results. As nervous discharges of all kinds are diffused and re-diffused until they affect the whole nervous system, we must regard every sensation, every thought, every emotion, as a propagator of disturbances, strong or weak, throughout the cerebral masses. The reverberations reach- ing plexuses in their ordinary states, draw from them but feeble reactions, and accompanying faint additions to the general body of consciousness. But when the reverbera- tions reach plexuses made unduly sensitive by the presence of much blood, the reactions of their elements are unduly strong — the gushes of nervous fluid liberated, escaping along the habitual lines of discharge, arouse the correlative states of consciousness not faintly but vividly; and these, standing out from the background of consciousness, become the predominant thoughts and feelings.
If these physical processes are extended to the whole brain, there result multitudinous vivid ideas not of one kind but of many kinds. All the cerebral plexuses being rendered by excess of blood unduly sensitive, as well as 608 PHYSICAL SYNTHESIS.
Initiators of unduly strong disturbances,, consciousness be- comes a torrent of intense thoughts and feelings; and if instead of congestion we hare inflammation., order and pro- portion among the thoughts and feelings are quite lost — there is delirium.
§ 264. From temporary insanity, partial or general,, of the kind caused by partial or general derangements of cir- culation., congestive or inflammatory, through the cerebral plexuses, we pass to the kind of permanent insanity that ensues when such derangements of circulation become per- manent.
If nutrition of a cerebral plexus is much raised, or much altered in kind, by great excess of blood, the thoughts and feelings initiated are likely to be intensified to a degree that constitutes them illusions — we get monomania. Carry- ing out the analogy above indicated, we may say that as a touch on an inflamed surface of skin arouses as much feeling as a cut would ordinarily do; so a hyperseinic nervous plexus excited by some slight disturbance, reacts as violently as it would ordinarily do only after a very strong disturbance: the correlative psychical efiect being the production of ideas that are unduly vivid — so vivid some- times as to be scarcely, if at all, distinguishable from per- ceptions. Supposing this state lasts, structural changes occur in all the tissues implicated. Greatly exalting for a time the rate of molecular change, producing thickening and deposits, and leaving a degradation of structure inconsistent with the due discharge of function, the hyperaBmia may, after making the correlative psychical states unduly vivid, end in enfeebling them — so entailing a changed form of mental affection.
If a chronic vascular derangement, or derangement of nutrition otherwise caused, extends to many or all of the cerebral plexuses, general insanity would seem fairly in- ferable. Should it be said that a deviation from the normal EVIDENCE FROM ABNORMAL VARIATIONS.
rafce of tissue-metamorphosis throughout the cerebrum at large, either by increase or decrease, would seem only to necessitate a corresponding exaltation or depression of all the mental powers, and not a derangement of them,, I reply as before (§ 260) that derangement of them is implied by any disturbance of the proportions among the intensities of states of consciousness., and that such disturbance is caused bv anything that modifies them all indiscriminately. If the strengths of the nervous discharges are so raised that those passing along the less permeable channels set up molecular changes,, and arouse correlative feelings, almost or quite as strong as the sensations aroused by peripheral stimuli, the gradations that normally exist among states of consciousness in respect of their degrees of vividness and degrees of cohesion,, are either destroyed or seriously altered — judgment beingper- verted to a proportionate extent. And a perversion of judg- ment will likewise result if, from an opposite physical cause, some of the states of consciousness become too faint or disappear.
It is needful to add that though thus far chronic vascular derangements, and derangements of local nutrition entailed by them., have been named as causes of insanity, the implica- tion that they are the only causes is by no means intended. Effete matters may, if they accumulate in the blood, produce molecular disturbances in the nervous centres through which they are continually carried; and molecular disturbances so set- up will have for their concomitants disorders of the mental states. Or instead of a normal product of decomposition that has not been duly excreted, some introduced virus., or some morbid matter arising from constitutional disease, may,, by thus acting as an irritant, perturb the ct^rents of thoughts and feelings. That an impure blood is thus a pos- sible, and indeed a probable, cause of insanity, we find good reason for believing, ~* § 265. For we "bring on a species of temporary insanity by E R 610 PHYSICAL SYNTHESIS..
put tins1 certain poisons into the blood. Substances which like opium and hashish, exalt the rate of molecular change in the nervous centres, so intensify the feelings and ideas as to cause illusions.
I need not follow out in detail the parallelism between the effects of increased pressure of nervous fluid produced bj these drills and increased pressure otherwise produced. Here, as before, there is such exaltation of ideal feelings as brings them near to real feelings in distinctness; sucli strengthening- of the relations among them as causes failing memories to arise with clearness; sucli facility in the forma- tion of remote and complex connexions of thoughts as constitutes a transfigured imagination; and such widening of consciousness as changes its quiet flow into a flood.
One thing only will I draw attention to — the verificatior yielded of a foregoing hypothesis respecting the genesis o: " states of mind." As a corollary from the laws of associa- tion translated into terms of nervous action, we concluded that when the pressure of nervous fluid is low, the diffused discharges will be so distributed that the faintly revivec feelings of pain will preponderate; that when the nervous pressure is up to par, the aggregate of feelings indistinctly awakened, pleasurable and painful, will form a neutral com- pound; and that when the pressure is high, the pleasurable elements of consciousness, relatively as well as positively increased in their amount, will constitute a sense of happi- ness. Here it is to be observed that artificial^ happiness ii produced bvj^rtific^ The delightfu reveries of the opiiim^eater constitute the temptation whicl he finds it so difficult to resist. And similarly with Indiai jeuTEK tf It is real happiness which is produced by hashish/ says 1L More an.
§ 26o, To complete the outline of the evidence furnishe< by abnormal variations, a few words must be added on th s, These change the nervous a€tions and EVIDENCE FROM ABNORMAL VARIATIONS.
correspondingly, change the states of xnind. Are the changes they work interpre table as agreeing with the foregoing general doctrine? In great measure,, I think,, if not wholly.
It is admitted as holding generally of these various agents — alcohol, ether, chloroform, nitrous oxide, &c. — that when their anaestEetic effects begin, the highest nervous actions are the first to be arrested; and that the artificial paralysis implicates in descending order the lower, or simpler, or better-established nervous actions. Incipient intoxication shows itself in a failure to form involved and abstract rela- tion of ideas, while it remains possible to form simpler relations. In the anaesthesia produced for surgical pur- poses, we have less opportunity of observing that the like happens; but assuming that it does so, we find all the successive symptoms conformable in their order to the hypothesis. According to M. Plourens and Dr. Snow, as quoted and, on the whole, endorsed by Dr. Anstie, the aether-narcosis produces the loss of — -" 1. The local sensi-" bility of extreme parts, and the control of certain musclea situated in those parts. 2. The intellectual powers. 3. The* power of co-ordination of the locomotive organs generally.! 4. The power of perceiving sensory impressions, even from parts little removed from the spinal centres. '5. The power of breathing. 6. The movements of vegetative life — e.g., of | the heart, intestines, &c" Here loss of the intellectual powers is placed after loss of sensibility cc of extreme parts "; but this discrepancy is due to the fact that paralysis of the higher intellectual powers, necessarily inconspicuous under the circumstances, is not specifically named, even where observable; and that only when the perceptions become confused are the intellectual powers set down as lost. The experiments, both with ether and chloroform, show clearly that some incoherence of thought is the first noticeable effect.
Making this correction of the statement, we may say that anaesthetics stop first the discharges along the incipient lines of nervous communication; next the discharges 612 PHYSICAL SYNTHESIS.
along lines a little better formed; and so on, until finally they stop the discharges along the fully-established lines. Limiting ourselves for brevity to the two extremes, we see that on the one hand, incoherence among the more involved thoughts implies that those least permeable channels of nervous discharge that have been formed by the compara- tively-few experiences of the individual, have become imper- meable • while, on the other hand, when the functions of the visceral nervous system cease, the implication is that dis- charges no longer pass even through those most permeable channels which have been inherited, in a ready-organized form, from an ancestry that runs back not simply through numberless individuals, but through numberless species.
Though the effects of anaesthetics thus yield confirmation of the belief that lines of nervous communication become perme- able in proportion as the discharges through them are strong and frequent, they present some apparent obstacles to it. How is the preliminary stage of excitement, and even mental exaltation, reconcilable with the- argument? How are the differential effects of different anaesthetics to be explained? How does it happen that in some cases sensation is abolished while there continues some consciousness of things around? I believe there are answers to these questions; but this general exposition, would be too much encumbered by in- cluding them in it.* § 267. I have reserved till the last what needs to be said in answer to objections which critical readers have probably made, now to one and now to another, of the several foregoing interpretations. This I have done with the inten- tion of ultimately pointing out that the interpretations 'must be taken not separately but together. The many ^causes of variation at work, interfere with one another in ^multitudinous ways and degrees — each is influenced by all and all by each.
* See Appendix.
EVIDENCE FROM: ABNORMAL VAIUATIONS. 613 Due co-ordination of any set of nervous discharges, aad production of the appropriate combination of mental states accompanying it, depends, primarily, on the existence of fitly-organized nervous plexuses in fitly-adjusted molecular states; and this pre-supposes that the approximately-adapted structures which the individual inherited, have had their adaptation completed by his own activities. It depends, secondarily, on the general supply of nervous fluid; and the physical processes and accompanying psychical states will vary according as the pressure of nervous fluid is high, or moderate, or low. And it depends, tertiarily, on ihe extent to which nervous fluid is being at the time drawn off by other discharges — to the viscera, to the muscles, or to other parts of the nervous system. Along with these general deter-"*' mining causes have to be taken into account many more special determining causes — the state of the blood as rich or poor, as well or ill crated, as freed or not freed from this or that waste matter; the state of the blood as containing morbid products or foreign substances; the supply of blood to the plexuses concerned, which depends partly on habit, as in- volving frequent or infrequent action of them, and partly onj the character of the blood vessels, as contractile or the re-j verse; and, lastly, the state of these plexuses as modified ] by chronic derangements of nutrition due to local inflaniina-* tion and its seqiielce.
Remembering that aU these co-operative causes have to be taken into account, we shall, I think, see little difficulty in reconciling the various anomalies with the general principle set forth.
CHAPTER X.
HESULTS- § 268. A not unsatisfactory fulfilment of the anticipation with which we set out has, I think, been reached. In the General Synthesis mental development,, traced up from its beginnings, was represented 'as a correspondence between inner and outer actions, that extends in Space and in Time., while it increases in Speciality,, in Generality, and in Com- plexity. The, Special Synthesis^ carried further this interpre- tation of mental development, by showing how the advancing correspondence, when translated into the more familiar terms of Reflex Action, Instinct, Memory, Reason, Feeling, and Will, is comprehensible as a continuous process natu- rally caused. And in the Physical Synthesis just concluded, this continuous process naturally caused has been inter- preted as a cumulative result of physical ^actions that conl^erve being supposed to have the molecular structure ;ind properties which, at the beginning of this work, we xmnd such numerous reasons for assigning to it; we have nferred from, established laws of motion, that the molecular phiange wrought in it by every discharge it conveys, leaves ft in a state for conveying a subsequent like discharge with resistance. This^being the universal^ law of nervous action, explains the universal law of intelligence. In the foregoing chapters we have compared the various corollaries RESULTS.
RESULTS.
of the one with, the various implications of tlie other; and we have found that, from the simplest to the most complex cases,, physical principle and psychical manifestation agree. Regarding as superposed, each on the preceding., the struc- " tural effects produced generation after generation and' species after species, we have formed a general conception of the manner in which the most complex nervous systems have arisen out of the simplest. Simultaneously, we have; been helped to understand more clearly the natures of the; various modes of consciousness — perceptions, ideas, emo-- tions, &c. And, by pursuing the reasoning to its remoter; consequences, we have found that both normal and abnormal f variations of mental processes, even up to the changes of:: rnood accompanying bodily changes and the ecstatic feelings f aroused by certain drugs, are rendered comprehensible.
The sufficiency of this general principle to account for the facts, can of course be alleged only on the assumption that changes wrought in nervous structures by. nervous functions are inheritable. Tacitly throughout the divisions preceding it, ancf avowedly throughout this Physical Synthesis, it has been taken for granted that from generation to. generation there descend alterations of structure; both of the kind called spontaneous, and of the kind arising from functional actions. Throughout the earlier stages of nervous evolution, a leading and perhaps most active cause, has been the survival of indivi- duals in which indirect influences have produced favourable variations of nervous structure. But throughout its later stages, the most active cause has been the direct production by functional changes of corresponding changes of nervous structure, and the transmission of these to posterity. Con- sidering how involved are the nervous systems <s>f superior creatures, there apply here with especial force the reasons before given (Principles of Biology § 166) for concluding that natural selection is an i^ad^guate ^,: cause _ of ^plution where' many co-operative parts have to be simultaneously modified; and that in such cases the inheritance of func- 616 PHYSICAL SYNTHESIS.
tionaliy-produced modifications becomes the leading agency — survival of the fittest serving as an aid.
But these processes of direct and indirect equilibration being postulated as acting on all organisms throughout all time,, we see that joining with them the inferred effect of every nervous discharge upon every channel passed through, we get an adequate explanation of nervous evolution,, and the concomitant evolution of Mind.
§ 269. Cf Thus, then, we are brought face to face with unl mistakable materialism/' will exclaim many a reader.
I " Thus, then, it is positively asserted that Mind is a growth, I and that it grows after the same general method as does the meanest fungus or the most degraded worm. Thus, 1 then, we must infer that the profoundest intuitions of the \ discoverer and the subliniest inspirations of the poet — the .most abstract conceptions of the mathematician as well as the noblest emotions of self-sacrificing sympathy — are but properties of certain matters arranged in particular ways."
Notwithstanding the explanations that have been from time to time given, such will, I doubt not, be a frequent apostrophe. So favourite a mode of meeting the inferences drawn, is sure to be again employed; though, as shown al- ready, it tells only against a doctrine that has been repudi- ated. The general relation between mental manifestations and material structures traced out in the foregoing chapters, has implications identical with, and no wider than, those which familiar experiences thrust upon us. That drowsiness impedes thinking, that wine excites or stupefies according1 to amount and circumstances, that great loss of blood produces i^niporary unconsciousness, and that th© un- consciousness of death results if breathing be stopped for a few minutes; are facts admitted by every one be his theory of things what it may. That you cannot get out of the undeveloped child, thoughts and feeling's like those you get out of the developed man; that the RESULTS.
RESULTS.
idiot, witli brain permanently arrested in Its growth,! remains permanently incapable of any but tlie simplest mental actions; are propositions not denied by the most in- temperate reviler of physiological psychology. Bat one who recognizes such facts and propositions, is just as much chargeable with materialism, as one who puts together facts1 and propositions like those which constitute the foregoing exposition. Whoever grants that from the rudimentary consciousness implied by the vacant stare of the infant, up^ to the quickly- apprehensive, far-seeing, and variously-, feeling consciousness of the adult, the transition is through! slow steps of mental progress that accompany slow steps oft bodily progress, tacitly asserts the same relation of Mind| and Matter which is asserted by one who traces out the evo- { lution of the nervous system and the accompanying evolu- \ tion of intelligence, from the lowest to the highest forms of | life.
But, as said here and before, the supposed implication is not the true implication. Let me once more point out what the true implication is. By way of preparation, however, we will first observe how the above apostrophe might be met by those to whom it would be fitly addressed.
§ 270. "Your reproaches seem to me strangely inconsis-y tent with your avowed beliefs and sentiments/'' might say the! materialist to his opponent. " You profess the profoundest? reverence for the Creative Power, from which you hold the ] Universe to have proceeded. Yet of the visible and tangible I part of the Universe, yon speak in a way that would be ap- \ propriate were its origin diabolical; and you taunt me be- j cause I recognize in that which you treat wrA. so much: scorn, powers no less marvellous than those manifested in the human mind.
" You see this piece of steel — cold, motionless? and, as - you suppose, insensitive to all that goes on around. An j- artizan uses a portion of it for making the balance-wheel of I 618 PHYSICAL SYNTHESIS.
a watch.. Immediately it proves itself modifiable by changes of temperature which, our dull senses fail to appreciate. " Though by no direct measures can we detect an alteration , in the length of its beat; yet, indirectly,, by finding that it loses one beat in a hundred thousand, we get proof that an •; imperceptible increase in the molecular agitation propagated I to it by surrounding things., has augmented its diameter and ; expanded all its parts in the same ratio. Take another bit of this same apparently inert substance; shape it appropri- , ' ately; bring it under tne influence of an adjacent magnet; and throughout its mass there is wrought., in some incom- prehensible way, an invisible change which enables it to do — what? ' To point north and south/ you say. Yes; but to i do far more than this. Its perturbations will now show to '|an instructed eye, the rise and progress of a cyclone in "And what is the constitution of this seemingly-simple .matter, which thus tells of things near and remote that re- 4 main otherwise unknown? In the minutest visible fragment 4. of it there are millions 0$ units severally oscillating with un- I imaginable speed; and physicists show us that the ampli- ;i J.tudes of their oscillations vary from moment to moment, I according as the temperatures of surrounding objects vary.
"Nay, much more than this is now inferable. Each unit is not simple but compound — not a single thing but a system ; of things. Spectrum-analysis has made it manifest that ' '. ' every molecule of this so-called- elementary substance is a , l cluster of minor molecules differing in their weights and j \ rhythms. Such being the complexity of matters we lately > 'j thought simple, judge what is the complexity of matters I * we know as*corapounds. In each molecule of an oxide or J,1} an acid, the chemist sees one of these systems united with J •» one, two, three, or more systems of another kind that j,|, are similarly involved. Ascending to orders of com- ,i | (J S pounds successively more heterogeneous, he finds him* '! if self obliged to recognize molecular complexities unve- '* EBST7LTS.
presentable in thought; until, on reacting organic matter,.• lie conies to molecules each of which (taking into account'' the composite nature of its so-called elements) contains literally more atoms than the visible heavens contains stars — atoms combined, system within system, in such ways that • each atom, each system, each compound system, each. doubly-compound system, has its motion in relation to the: rest, and is capable of perturbing the rest and of being per-; turbed by them.
"This activity and this sensitiveness, which the investigator I marvels at the more the deeper his discoveries.reach, is pos-f sessed in common by ponderable matter and by the seem-? ingly-imponderable matter ^pervading. space. That the ether, { so extreme in tenuity that we can scarcely represent it to ourselves as having materiality, is nevertheless composed of units which move in conformity to mechanical laws, is now a common-place of science. Hypo the tically endowing these units with momenta, and assuming that in each undulation their courses are determined by composition of forces, mathe- maticians long ago found themselves able not only to inter- pret known properties of the. light constituted by ethereal':' undulafions, but to assert that it had unobserved proper-' ties; which were thereupon proved by observation to exist.- Far greater community than this has been disclosed be- tween the ponderable and the imponderable: the activities of either are unceasingly modified by the activities of the other. Each complex molecule of matter oscillating as a '• whole — nay, each separate member of it independently oscillating, causes responsive movements in adjacent ethereal. molecules, and these in remote" ones without limit; while, conversely, each ethereal wave reaching a composite molecule, changes more or less its rhythmical motions, as well as the rhythmical motions of its component clusters and those of their separate members. *> cc Nor do the revelations end here. The discovery that matter, seemingly so simple, is in its ultimate structure so t 620 PHYSICAL SYNTHESIS.
amazingly Involved; the discovery that, while it appears to De inert, it is the seat of activities immense in quantity and complication; and the discovery that its molecules, pulsat- ing with almost infinite rapidity, propagate their pulses into the all-surrounding ether which carries them through in- conceivable distances in infinitesimal times; serve to intro- duce us to the yet more marvellous discovery that molecules of each kind are specially affected by molecules of the same kind existing in the farthest regions of space. Units of sodium on which sunlight falls, beat in unison with their kindred units more than ninety millions of miles off, by which the yellow rays of the Sun are produced. Nay, even this is a totally inadequate illustration of the sympathy dis- played by the matter composing the visible Universe. The elements of our Earth are thus connected by bonds of inter- dependent activity, with the elements of stars so remote that the diameter of the Earth's orbit scarcely serves as a unit of measure to express their distances.