its healthy functions; and in order to this, there must be a sound state of the lungs, and a pure atmosphere easily and freely inhaled; conditions of indispensable importance in order that the blood may not be imperfectly oxygenated; and that the brain may not suffer in consequence of that fluid's being deprived of its highest vital qualities. Therefore if the brain and its manifestations of mind be impaired by receiving a blood unsuitable for its pur poses, how much more will it be perverted by the action of that fluid when impregnated with absolutely noxious particles?

IV. Sympathy of the brain with the stomach and alimentary canal.

I must next notice the connexion, and listen to the sympathies, existing between the brain and the stomach, together with the alimentary canal; and we shall here also find how completely the latter are dependent upon the former, and observe the consequent influence excited by any morbid cause of irritation existing within either.-In the first place, the stomach receives from the brain certain nerves, the integrity of which is indispensable to the performance of its function of digestion or alimentation. Destroy this communication, and the action of assimilation ceases: this at least proves the close connexion between the two organs, and will afford room for suspecting that any morbid change in a function so entirely dependent upon the brain, must reflect its irritating influence upon the source from which all power of healthy action is derived. But further the influence of prolonged study in diminishing the digestive power, and the gradual wasting of the flesh, and general exhaustion, which follow from a severe course of reading; the suspension of appetite, and the indigestion after eating, which arise from any sudden and considerable mental emotion; the destruction of the tone of the stomach, the chronic irritation, and even ulceration of its

coats, from the slow and invidious but certain effects of grief and disappointment, when suffered to prey upon the mind, without seeking for the consolations of religion: the nausea and disgust which, in some individuals, are produced by the sight or smell of certain articles, which have formerly proved injuri. ous to them, and which declare these senses to be appointed as faithful sentinels to the system, and to enable us at the same time to trace the limits of association between function and function: the absolute sickness which will sometimes result from the preceding state, and particularly from the idea of swallowing that for which we have a decided aversion; a similar effect sometimes produced from mere nervousness, that is, from mental emotion: the participation of the stomach in almost all the maladies with which the brain is directly, or indirectly, affected, and the expression of its uneasiness being sometimes the only symptom which would lead to a suspicion of irritation of the brain: the frequently severe disturbance of the stomach, called "sick head-ache," and which originates primarily from an affection of the brain; or from concussion or compression of that organ, or on recovery from fainting;-all shew how completely the former is under the influence of the latter, and betray the intimate sympathy between the two functions; which is still farther confirmed by the cerebral uneasiness and disorder in diseases of the stomach.

We may elucidate this state of morbid sympathy, by contemplating the rationale of some of its healthy functions. Hunger and thirst, for instance, and the desire of satisfying appetite, although frequently referred to the stomach, do not exist there; but are the results, when unsophisticated, of the wants of the system impressed upon the nerves of the stomach, and referred to the brain, in order that volition may be excited to satisfy those wants, and to preserve that system. When the

desire has been satisfied by taking food, a feeling of comfort will be diffused over all the animal machine,if the stomach has been moderately supplied; accompanied, how ever, with a degree of languor, and indisposition for intellectual exertion, and the desire of quiet in order that the cerebral system may be fully occupied with the important process of digestion, without the peculiar aid of which the powers of the stomach would ultimately fail. In many persons of weakly digestion, a disposition to drowsiness occurs; and the other functions of the system are not in activity, in order that all the nervous influence that can be spared may be concentrated upon the stomach. Where the meal has been moderate, all this passes without notice; but if the stomach shall have received more than it can conveniently digest, the attention of the nervous system is directed towards it, and the patient feels oppressed. And if this oppression be frequently repeated perhaps every day, and several times in the day-permanent feebleness of intellect will be the result; because the energies of the brain are accumulated upon the animal system, and cannot be afforded for its intellectual functions. Hence it is, that by experience, persons engaged in literary pursuits, in extending the field of their own intelligence, or in communicating knowledge to others, know and feel that a full diet is incompatible with intellectual activity. Moreover, many extraordinary affections of the brain occur during difficult digestion: nay, spectral illusions, and often nervous symptoms, which shew that that viscus is irritated; and that when irritated, there is no placing bounds to its actions. We must here also notice the effects produced upon this organ by various substances; and particularly by alcoholic fluids, tea, and coffee. As a very slight stimulant the former is sometimes recommended, even by medical advisers; but when the quantity is

considerable, the stomach suffers sooner or later; and, where a habit of drunkenness is continued, generally suffers irrecoverably. But it is with the effect upon the brain, and its manifestations of the mind, that we have chiefly to remark. In moderate doses, alcoholic fluids excite that organ gently, and stimulate the employment of its functions; a degree of hilarity is observable; a rapid flow of ideas; increased acumen in disputation; lively sallies of wit; and generally augmented powers ;-but when the quantity taken has been larger, reason is suspended; it is absolutely drowned in some instances, perfect insanity is produced; in all, the senses become obtuse. The muscles refuse obedience to the will; the patient is unable to walk without staggering, or to speak without stammering; and in a more advanced stage of inebriety, the power of the brain is apparently lost; a deep heavy apoplectic slumber comes over the patient, from which, after a certain interval, he awakens, stupid, enfeebled, with head-ache, languor, debilitated moral and intellectual manifestations, depression of spirits, and the consequent anxiety for a renewed dose of this deadly stimulus. Disease, and perhaps suddenly fatal disease, frequently results from drunkenness and where this may not be the immediate consequence, the continuance of the habit gradually terminates in an enfeebled brain; the individual is reduced below the level of the brute animal creation; and his besotted intellect is more and more clouded, till he becomes childish, fatuous, palsied, and lives out only half his days. There is, therefore, great danger in the habitual use of even slight alcoholic stimulants; for by custom a larger dose becomes necessary, as the excitability of the organs is lessened : till at length, what was taken perhaps at first with caution, and it may be with a view to health, becomes deeply injurious both to the mind

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and body, and leads on the unconscious victim to the miserable state I have described. The highly alcoholized wines used in this country, are a slow poison to thousands of persons who, from long habit, cannot feel wound up without them, and are not even aware that they are every day unduly stimulating the system, and bringing on premature decay, imbecility, and old age. Tea and coffee, on the contrary, excite the brain without producing these deleterious effects, or at all endangering the manifestations of mind; they cheer, but do not inebriate. They appear to communicate a great facility in forming, arranging, and communicating ideas: thought be comes rapid, acute, and of a superior order; composition, conversation, every effort of mind, becomes easier, more valuable, more perfect; and inappreciable energy is communicated to the mental operations. It must be allowed, however, that their habitual employment renders them necessary in order to secure a certain brainular stimulation,without which the energy of the organ is below its average power; but this only proves still farther the dependence of mind upon matter for its manifestations, and that, too, upon the condition of a distinct organ. It must also be recollected, that persons possessed of a highly nervous, susceptible, irritable temperament, cannot take these substances with impunity, much less with advantage; for the equilibrium of an already too highly irritable organ is disturbed, and wakefulness, with many a symptom of uneasy nervous disorder, is produced.

I must not entirely pass over the action of opium; the more especially as we shall have occasion to refer to it hereafter. It is well known, that this medicine is distributed to the Turkish troops, on the eve of an expected battle, in order to produce in them that exultation of animal power, and that fanatical ardour and courage, for which they are remarkable. When taken under ordinary

circumstances, and in precisely the right dose, it will occasion agreeable sensations, enchanting reveries, and pleasures which are indescribable. It is well known that this remedy has been often abused for the purpose of creating supernatural appearances, visions, and other illusions, which have been ascribed to the agency of heavenly spirits. This subject might be extensively pursued; but, probably, enough has been brought forward to shew the dependence of cerebral phenomena on the state of the brain; and to prove how much its manifestations may be disturbed by any irritation of the stomach-an organ peculiarly liable to this morbid state, from the variety of its own diseases, its extensive connexions, and its mischievous dietetic management.

V. Sympathy of the brain with the liver.

I shall here only just notice the influence of moral causes upon the functions of this organ, so that an excessive flow of bile does often result from the mere agitation of suspense or surprise; while the more powerful passions, such as anger, fear, terror, excessive joy, have actually produced a fit of jaundice. Then again its reflected influence is very considerable; headache, and a countless variety of morbid mental manifestations, have frequently followed congestion of its vessels; and their removal has been coincident with its returning health: while, on the other hand, concussion of the brain has often given rise to inflam mation, and even abscess of the liver. The well-ascertained influence of diseases of this organ in producing hypochondriasis, melancholy, and many other forms of vaporous irritation, is also proverbial, and tends to confirm our position, that its functional disturbance occasions a sympathetic disorder of the intellectual organ - not of the mind, but of the material through which it acts-possessing a specific character analogous with that which constitutes the primary irritation.

In what this character consists we know not; nor is it necessary that we should know, since we seek not to define the nature of this influence, but merely to indicate its extent.

VI. Sympathies of the brain with the function of secretion in general. We must pass over the influence of the kidneys, the spleen, and several other organs of the body: but as these are for the most part secreting organs, we shall just notice the agency of the brain in producing secretion at all, and its reflex operation upon that viscus. This function very much depends upon the brain, and can be continued only so long as a due correspondence is kept up with that organ. But there are some secretions which conspicuously exhibit this law; that, for instance, of saliva under the influence of the excited imagination of food on the opposite side, disgust for certain articles of diet will arrest the secretion, and produce dryness of the mouth. Again: the secretion of tears may be produced by two very opposite mental states either of great sorrow or joy; and in both cases their flow seems to afford relief to an oppressed brain -the suffering organ of the mind. This is a matter of common observation, though its cause is not contemplated. Every one has experienced the temporary relief afforded by this secretion to a bursting heart; and there are few who have not rejoiced when they have witnessed tears come to the relief of an oppressed bosom; for they know that a sorrow, which can find an outlet in these natural expressions of grief, is less injurious than that deeply-concentrated feeling, which has no way of utterance, and in which the individual remains as isolated from himself and others, and frequently falls a victim to cerebral disorder. This influence is also indirectly exerted upon the chest, so that the phrase of being "stifled with grief," is often used to depict a state in which the oppressed bosom can scarcely free itself

from its load, and is accompanied by a sense of stricture and tightness very commonly known; and which, in the nature of things, must depend upon cerebral influence. Parents are accustomed to act upon this principle, without knowing why, and without reasoning upon it: as, for instance, in the choice of a wet-nurse for their infant, they would look for one endued with a good share of equanimity, whose system was not liable to the agitation of tumultuous passion, and to moral affections of a debased character; because the influence of these mental states upon the secretion of milk is known to be deleterious, and to render it improper for the nourishment of the infant; even if it do not still farther exert an unfortunate effect upon the brain, and on the consequent manifestations of mind.

VII. Sympathies of the brain with the muscular system.

The influence of the brain on the muscles is conspicuous in several forms of malady, as well as in their more simple healthy actions. They may be considered as agents to the brain, and absolutely incapable of their action without its continued energy imparted to them. A proof of this may be found in that state of a limb which is termed being "asleep." By pressure on the nerves, the communication with the brain has been intercepted; and the individual wills in vain to move the limb: motion is impossible till the return of nervous influence, marked by the common sensation of "pins and needles," has restored the communication with the brain, and the muscles become again obedient to the will. Although from long habit these organs may appear to act without a distinct effort of volition, yet it is manifest that this really happens from the so-frequent repetition of cerebral actions, that the precise operation is performed without exciting the attention. further proofs were needed of this position, they might be found in

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