comprehended. This knowledge is indispensable, in order to make proper observations, and to establish general principles in pathology. First, If we were perfectly acquainted with the functions of every distinct portion of the brain, we should then know precisely what parts to examine in case of disease, and would thus be far more likely to discover the morbid derangements in function, or the nice changes in structure, that may exist. Secondly, The various parts of the brain sustain very intimate and important relations to each other in the performance of their functions, including muscular motion, sensation, and mental operations. Now, these several relations and connections must first be understood in a healthy state, before we can clearly perceive the causes or effects of disease in all the parts of such a complicated viscus. Thirdly, The brain is subject to a great variety of affections where no indications or traces of change in organisation have ever yet been discovered by the best pathologists. Whether this difficulty arises most from the extreme delicacy of its texture, or the want of more perfect instruments for making the examination, it is unnecessary here to decide. But it frequently happens, as is rendered evident by external symptoms, that very great functional derangement actually exists, and, according to all analogy, there is every reason to believe that some change in physical structure must either have preceded, or been occasioned by this derangement. Now, a thorough knowledge of the functions of the brain, embracing the various kinds of motion and sensation, as well as mental manifestations, will not only incite, but enable us to recognise far more accurately the kind and degree of deviations in these, from a state of health. We may thus, by continuing this mode of inquiry and examination, be able to detect changes in organisation which have hitherto entirely escaped the closest scrutiny of pathologists. Hence we see that a knowledge of physiology must precede that of pathology, and that mental philosophy sustains, in this respect, also a most intimate and important relation to medicine.

Practice of Medicine.-Aside from good natural abilities, two things are indispensably requisite to constitute any individual a successful practitioner of medicine. First, He must be thoroughly and practically acquainted with the causes and symptoms of disease: and, secondly, with the nature and application of the most appropriate remedies. And the more complicated the disease and difficult its treatment, the more important that his knowledge should be accurate, extensive, and well grounded. This is emphatically true, in reference to nervous diseases. It is admitted in the Library of Practical Medicine the most recent and popular work on the subject that "the

diseases of the brain are, at the present moment, more obscure than any other great class in the nosology."

While there has been a constant improvement in the diagnosis and treatment of diseases affecting every other part of the human system, there has been comparatively but little advancement in respect to those of the brain. Dr. Stokes, in his valuable lectures on the Theory and Practice of Physic, has very correctly adduced the following circumstances as causes for such a state of things. "First, The great obscurity of the symptoms; secondly, The want of correspondence between symptoms and known organic changes; and, thirdly, The necessarily imperfect nature of our classification of nervous diseases." Let us briefly examine these points. Now symptoms, according to this same author, consist "in certain changes produced in functions." But we have already seen that large numbers in the medical profession are wholly unacquainted with the real functions of the brain, and therefore they cannot judge clearly and rationally of the kind or degree of functional derangement; and hence the great obscurity attending the symptoms of diseases of this organ. We have, moreover, seen that mental operations constitute one of the most important functions of the brain—that the exercise of every individual faculty of the mind depends on a distinct cerebral organ-but how little is definitely and practically known concerning the healthy or morbid manifestations of these faculties? The knowledge that is already possessed on the subject is altogether too vague, indefinite, and speculative, to be applied to any practical or useful purposes in medicine.

The fact is, the study of mental science, as based on the functions of the brain, must, and will, in the process of time, constitute one of the most important features in the diagnosis and treatment of the diseases of this organ. As to the "want of correspondence between the symptoms and known organic changes," this is easily explained. It is more apparent than real; for nature never contradicts herself. It originates chiefly from a false view or classification of symptoms, and this, consequently, from an imperfect knowledge of functions. There may be, we admit, more than usual difficulty in ascertaining and settling this correspondence in the pathology of the brain, but a certain connection must necessarily exist between its functional derangement, and change in physical structure, according to all the known laws which govern organic matter; and we have not the least doubt, but the precise kind and extent of this correspondence will yet be discovered and established.

The third difficulty in the way of understanding nervous diseasesviz. their imperfect classification-grows out of the two former, and

can be rectified only in proportion as the functions of the brain become clearly and fully understood. The classification of no science whatever can be correct or perfect, unless it is based on a true interpretation of all the facts and phenomena in nature appertaining to it. That the physician should be well acquainted with the most appropriate remedies in the practice of medicine, requires no argument to prove or enforce.

III. The importance of a knowledge of mental science to the physician. This subject may be viewed under two general aspects :— first, as connected with the duties which he owes to his profession; and, secondly, in the relations which he sustains to the public. It will be seen from the preceding observations, that neither the anatomy, physiology, nor pathology of the brain, can be clearly and fully understood without a knowledge of its functions, or, in other words, of mental philosophy; moreover, that such knowledge is an indispensable requisition, in order to understand correctly the diseases of the brain, as well as to perform successfully many operations in surgery for injuries of the head. This knowledge is especially important, inasmuch as the principal and almost the only means we have of ascertaining the affections of this organ, is through the kind and degree of its functional derangement. We have no stethoscope to examine the state of the brain; neither can we form or correct our diagnosis by the physical signs of auscultation and percussion; neither is the brain, like most other parts of the body, susceptible of much pain from disHence the great importance of understanding the functions of this organ, particularly of those portions connected with mental operations; for the morbid or deranged manifestation of these will constitute the surest and most unequivocal symptoms of disease. To speak of mental excitement or depression in general terms, is not sufficient. We must know what particular faculty is involved, and how much it is affected. We might by such a course of diagnosis anticipate the very first intimations of nervous diseases, and thus employ remedial agents to much more advantage. It is not at all improbable but that a better knowledge of the functions and diseases of the brain will enable us to apply certain articles in the materia medica with far greater efficacy and success; new medicines may in this way yet be discovered, or different combinations made of those already in use.

ease.

Again: A knowledge of mental philosophy cannot fail to be of great advantage to the physician in the treatment of disease. That the state of the mind has a powerful influence over the body, either for good or for ill, has been universally acknowledged. It was remarked by Dr. Rush, that "consumptions, fevers, convulsions, diseases of the stomach and bowels, visceral obstructions, apoplexy, palsy, madness, with a

numerous and melancholy train of mental diseases, are frequently brought on by the undue action of the passions upon the body." All must admit that the faculties of the mind operate as most powerful agents, either as causes or remedies of disease. A multitude of facts might be cited, where the exercise of certain mental faculties has proved entirely effectual in preventing or curing various affections. In this way, a salutary and healing influence has been exerted upon the body when all other medicinal agents have been found utterly useless. It is to this source that quackery and empiricism in medicine is chiefly indebted for success. It is by operating upon the feelings of patients, that quacks perform so many wonderful cures, and infuse. such a magic charm into their patent drugs. How important, then, that the regular bred physician should be thoroughly familiar with the nature and application of an agency so efficient and powerful in the treatment of disease? But it is not enough to be acquainted with the powers or faculties of the mind, in a vague, abstract, and general manner-such as love, hope, joy, grief, fear, sorrow, anger, &c. &c. We must know what particular organ in the brain is called into exercise at the same time-what is the precise character and strength of its mental faculty, and what are the most appropriate motives to be addressed to it. We must understand the nature and operation of those great laws which every where invariably regulate mental manifestations, and be able also to explain every fact and phenomenon connected with individual minds. The physician, of all others, should be competent to do this to his patient, and a system of mental science, based on the functions of the brain, places within his power the means of obtaining such information. He would be able, in this way, to recognise at once the peculiar temperament or idiosyncrasy of every individual patient, and could thus take the advantage of a multitude of circumstances of which he would otherwise be wholly ignorant. It is by pursuing such a course, that a knowledge of mind. can be rendered, in its applications, a "hundred fold greater," in the practice of the healing art, than the world has ever yet witnessed.

Again: The cultivation of mental philosophy is calculated to exert a most beneficial influence upon the progress of medicine. Our present limits will permit us to notice only a few of the advantages derived from this source.

1st, It will tend to do away with many groundless theories, hypotheses, and speculations, which, more than any thing else, have retarded the progress of this science. A large number of the works on medicine are comparatively worthless, because they are, in a great measure, filled with the mere rubbish of theory, controversy, and the opinions of men who cannot be considered as competent judges or

safe guides. These theories are partly of ancient, and partly of modern origin. The cultivation of medicine formerly partook very much of the manner and spirit in which metaphysics were studieddealing in abstractions and generalities, without sufficient regard to facts, or the nature of the evidence upon which they were professedly based. The inductive philosophy, introduced by Lord Bacon, produced quite a revolution in the study of medicine, and pointed out the true mode in which every department of this science should be cultivated; and by means of which, most of its discoveries and improvements, for the last fifty years, have been effected. Now, a system of mental philosophy, based on the functions of the brain, is founded upon the most extensive induction of facts, and enforces at every step the absolute necessity of observation and experiment. It will, moreover, tend to bring into constant exercise the observing faculties of the medical student, and render him exceedingly cautious that his conclusions are always founded upon correct data. It will thus prevent too hasty generalisation in medicine, and eventually become a standard to test the truth or falsehood of every new doctrine which claims to be based upon the great laws of physical organisation.

2dly, Such a system of mental philosophy will enable us to test the real merits of the opinions of men, and decide how much weight should be given, in matters of science, to mere human authority. There are four classes of persons whose opinions in medicine should always be scrupulously examined, and on certain subjects they should be entirely set aside, no matter how extensive their experience or profound their attainments; the difficulty arises from the peculiar constitution of their minds. The first class may be characterised as possessing very strong observing faculties, with quite deficient reflective intellect; these may observe, collect, and understand facts to any amount, but can never perceive or comprehend the force of principles, because they are naturally deficient in the powers of analysis and ratiocination. This class are not, therefore, competent judges wherever general principles are concerned. The second class of persons possess minds of a directly opposite character, having strong reflective faculties, but weak perceptive intellect; such individuals are not much given to observation themselves, neither can they appreciate the importance, or see the bearing, of facts in reasoning. They are inclined to dwell almost exclusively upon general principles and abstract relations, and not unfrequently become very speculative and visionary in their views. Consequently, their opinions on all practical subjects must be received with much caution. The third class may be described as possessing, naturally, such an inordinate degree of self-conceit and firmness, as to render them blindly obstinate, and VOL. III.-17