We are further indebted to Sir B. Brodie for the first description of that very remarkable hysterical affection of the joints, which has close kindred with the disorder now under consideration. They are, in fact, corresponding effects of a common cause, and require for the most part similar treatment for their relief. I have often found cause to suspect, as stated in a former chapter, that some of the various forms of hysteria belong more especially to the gouty temperament, ranking among its other anomalous manifestations.

Looking generally to the cases associated together by this common character, they may be considered as amongst the most curious and instructive in all pathology. Like insanity and intoxication, they illustrate many points in the connexion of the mind and bodily organs, which are not equally obvious in the healthy state: and they instruct us, moreover, in the history of insanity itself, by displaying various partial hallucinations of mind, often traceable throughout their whole progress, and forming links, as it were, betwixt reason and madness. It is a sort of natural analysis afforded us of conditions too complex for examination, when they are fully formed and established.

the earliest distinct exposition of this class of facts, and their application to the phenomena of spasmodic diseases; a very important step in physiological science, and promising to have much future value in practice.

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CHAP. XII.

ON THE BRAIN AS A DOUBLE ORGAN.

I AM not sure that this subject of the relation of the two hemispheres of the brain, has yet been followed into all the consequences which more or less directly result from it. Symmetry of arrangement on the two sides of the body is common indeed to all the organs of animal life.* But the doubleness of the brain, like all besides pertaining to this great nervous centre, offers much more of curious speculation than the same constitution of other parts. That unity of consciousness in perception, volition, memory, thought, and passion, which characterises the mind in its healthy state ("illud quod sentit, quod sapit, quod vult, quod viget"), is singularly contrasted with the division into two equal portions of the material organ, which more immediately ministers to these high functions. Yet, on the other hand, in the almost exact symmetry of form and composition of each hemisphere; in their relation precisely similar to the organs of sense and voluntary motion on each side the body; and in the structure of the nervous connexions subsisting between them, we find argument, not merely for the correspondence of functions, but even for that unity or individuality, of which consciousness is the interpreter to all. This unity indeed, as it actually exists, is of necessity compatible with the conformation of the

*The distinction established by modern physiologists between the animal and vital organs, as respects the symmetry of the sides, is an important one, and well sanctioned by facts.

M

brain as a double organ, even had we no such presumption to refer to.*

Here, it must be admitted, we are close upon that line, hardly to be defined by the human understanding, which separates material organization and actions from the proper attributes of mind the structure which ministers to perception from the percipient -the instruments of voluntary power from the will itself. Our existence may be said to lie on each side this boundary; yet with a chasm between, so profound and obscure, that, though perpetually traversing it in all the functions of life, we have no eye to penetrate its depths. If we sometimes seem to obtain a show of further discovery (and human thought has exhausted itself in the effort), this arises generally from the deception of language, which gives the appearance of advancing, when in truth we are but treading in our former steps.

While approaching these limits, however, in the subject before us, it may be pursued to a certain extent within the boundary. Many of the questions of greatest interest here have not more concern with materialism, than have the facts which connect dreaming and intoxication with certain physical changes occurring in the body. The intellectual exist ence, of which consciousness and personal identity are the simplest expressions, but which spreads itself out into the

* Though the nervous system in all its parts, with the exception of that belonging to the great sympathetic, is subject to fewer anomalies than any other organs of the body, yet are these deviations more frequent in man than in many of the mammalia most nearly approaching to him in structure; an observation made originally by Vic d' Azyr, and confirmed by later physiologists. It is further to be noticed, as an anatomical fact, that in the brain and spinal marrow, the external parts on the two sides are less exactly symmetrical than those within; the surface of the brain showing this perhaps more distinctly than any other part. See Meckel's Handbuch der Menschlichen Anatomie, vol. i. ch. 3.

endless varieties of thought and feeling (μη χωριστη κατα μέγεθος, αλλα κατα λογον), has been given us, subject to external agents from the first moment of our being; both in the functions of health, and under the various circumstances of disease. And any results we may obtain from the inquiry

* I know no happier expression of personal identity, and its relation to the nature of mind, than that of Mr. J. Smith of Cambridge. 66 Mere matter could never thus stretch forth its feeble force, and spread itself over all its own former pre-existences." The same argument (for the force of the remark renders it such) may be followed into the future, as well as fetched from the past; and still more remarkably, as respects the intellectual existence of man. By facts already attained, and methods of thought previously acquired, the mind becomes capable of passing beyond its actual knowledge, and gaining what may be deemed certainty as to the result of combinations which have never yet existed; or, if existing, have never before been the subject of human observation. Physical science abounds in examples, where predictions thus made have been verified in the event. The conversion, by two reflections in glass, of the plane polarization of light into the circular, is an instance of the highest class of such generalizations directed towards the future, and realised in the progress of research. The undulatory doctrine of light offers other examples no less remarkable, in the anticipation, by a profound theory, of complex effects, wholly unknown as facts, and even in seeming contradiction to all the analogies of the science; yet which experiment afterwards established as real, and in harmony with the other laws of light. The loftiest attributes and objects of a philosophical spirit all lie in this direction. Here it is, in passing from "the region of facts to that of laws," that man takes his peculiar position in the scale of created beings; and here, also, that the intellect of one man stretches furthest beyond that of another.

Under the same aspect (for all the higher views in science associate themselves into principles of common truth) we may best view the great argument regarding causation — the "selva oscura" of philosophy, as it has been ever rendered by the inefficiency or ambiguity of language applied to the subject. The frequent misuse of the term final causes (perhaps even the adoption of the phrase at all) may be cited as one of the chief sources of error. No proof of efficient and intelligent causation, as distinguished from the bare sequence of events, is more complete and convincing than the power we possess of predicating results which have never

are but further examples of this essential condition of our existence in the present state.

If making a single comment here upon the question of materialism, it would be that the advocate for an immaterial principle is often unjust to his argument, in his assiduity to rid himself of those facts which attest the close and constant action of matter upon mind. They are too palpable, not merely in matters of sense, but also as regards the purely mental processes, to admit of any evasion. evasion. His true doctrine lies beyond this, in asserting a principle submitted indeed to these influences, but different from them; - capable of independent changes and actions within itself; — and, above all, capable of self-regulation in those functions of thought and feeling, to which external agents minister in the various processes of life. The ministering agents may become disturbing ones, and such they frequently are to a singular extent; but in this we have no proof of indentity. Whatever of reason we can apply to an argument insuperable by human reason, is against it; and the record of such instances is wholly comprized within that one great relation, which pervades every part of our present being; but the intimate nature of which is a sealed book to human research.

We may then as fairly reason upon the states or changes of mind depending on the brain as a double organ, as we

occurred to us before, but which arise out of laws so fixed and general, that we can safely anticipate the unknown from what we already know. In pursuing science along this path (the happiest exercise of man's divination), we obtain certainty of an intelligent cause from a source hardly separable from the consciousness of our own intellectual existence. And in thus making the highest efforts of the human faculty the interpreters of the principle of divine causation, we bring our conception of moral cause into closest relation with the physical, and gain not only elevation, but distinctness and stability to all our views on the subject.