« VorigeDoorgaan »
canal, ceases to impart the sensations of touch, and of heat and cold. Still more wonderful, and if we were to adopt Dr. Sewall's mode of reasoning, incredible, are the differences in function of the several divisions of the gastro-intestinal cavity, especially of the stomach, the duodenum and other small intestines, and the colon—continuous as are these one with another, and performing their respective offices through the medium of a membrane (the mucous) which exhibits, throughout, no differences adequate to enable us to tell, à priori, the changes of the alimentary matter in its passage over it. Surely, the most enthusiastic anatomist will not pretend to say that the stomach gives evidence in its "structure and organisation" of the part which it performs in digestion ? Neither this nor any other function has been discovered by the peculiar structure of the organ on which it depends. All have been ascertained by observation; by noting the relation between the stimulants and exciters of the organ itself, and not by any evident relation between the structure or mechanism of the organ and its sunction. It is true that, the function once ascer. tained, we can then see, in some instances, as in the mechanism of the heart, the direction of its valves, and of the valves of the veins, the adaptation of organisation to function. But even in this case, clear and evident as are the organic arrangements, they did not of themselves, if at all, prompt or guide to a discovery of the office for which they were intended.
The first inquiry, therefore, of Dr. Sewall" How far phrenology is sustained by the structure and organisation of the brain ?"--may be answered by saying ; just as far as any part of physiology is similarly sustained. If we are content to believe in the functions of the other organs, without this kind of evidence, we need not be sceptical in regard to those of the brain.
But the function of an organ once known, we can predicate, in general, from the quantity of specific tissue or structure of the latter, the power of the former. And this axiom, overlooked by Dr. Sewall, is the best answer to his denial of the fact, that there is any established relation between the volume of the brain and the powers of the mind. The contractility of a muscle is in proportion to the quantity of fibrinous matter of which it consists, and its motive power is in proportion to its size-not adventitious size, by intervening adipose and cellular tissue, or by infiltrations in them, but true bulk, made up of a deposit of fibrin. The larger a healthy heart, that is to say, the more it abounds in muscular fibres, themselves made up mainly of fibrin, the more powerful is its expulsive and propelling action, and the greater its energy as the central and chief organ of the circulation. So, also, of the function of the liver,
as measured by the amount of its secreted-fluid : it will be greater the larger is the organ, and the more bulky its peculiar parenchyma, and the more numerous its acini. Size, when caused by disease, ceases to be a measure, as where there is a fatty degeneration of the liver, or where the growth is of the cellular tissue intervening between the vessels and the acini and excretory ducts, or where this tissue is partially infiltrated with serous fluids.
The brain is no exception to this physiological axiom. This organ consists of a deposition of neurine, enveloped by membrane, and copiously supplied with blood. Its laws of nutrition are the same as those of other organs; its activity and stages of function will be found to correspond with its periods of developement and its size. We suppose now that we are addressing those who believe that the brain is the material instrument of the mind, without reference to specification of organs, whose functions consist in the performance of special faculties. If the brain be this grand instrument, we would ask, wherein consists its peculiarity of structure and organisation for this purpose, if not in the deposition of neurine, and the fibrous arrangement of the latter? The convolutions and ventricles are secondary modifications of structure, by which greater volume and expansion of surface are secured in the same space.
We only invoke the application of admitted physiological laws, when we affirm that the brain must, like every other organ, in order to discharge its appropriate functions, have acquired a completeness of growth and a developement, measured not only by the harmonious relations of its several parts and outlines, but also by the internal or interstitial deposit of its peculiar distinctive element. The greater its size, provided always this depend on the abundance of its peculiar element, the more apt and powerful will be the display of its functions ; just as the larger the muscle and the more abundant its fibrinous part, the greater is its motive power. As we cannot believe otherwise, than that there is a direct and positive relation between function and the matter and organic arrangement of the brain, so neither can we understand why there should be increase of this matter without increase of power of the function; unless we were to suppose that there is a superfluity of organ, and a waste of skill in the great Architect. Not only would this waste be exemplified in the needless quantity of brain, but in the needless extent of membranes and capacity of bony case for its investment and protection, if a large brain had no more power than a small one. It is not thus that we find his intention expressed, or rather marred, in the laws of structure and function in the organs of the body at large; and hence we have no right, from any abundant zeal with which we may be
actuated, to impute to him imperfection in the case of the brain, the more especially when we would profess at the same time to glorify him, by denouncing certain doctrines as favouring materialism and fatalism.
When speaking of the size of an organ, it will have been seen that we were careful to specify a size maintained by a healthy growth of its peculiar structure, and deposition of its peculiar element; and not on the enlargement of common tissue, or an adventitious deposit between its fibres. Size in health is indicative of the actual amount of organised matter, and the latter is again of the completeness of functional effects to be obtained from it. In disease, the size of an organ may, and often does, depend on other conditions ; some, and the chief of which, have been already mentioned. In this case, as where we see a large and dropsical brain, for instance, size is not an evidence of power and strength of mind; any more than the muscles of the limbs, large by infiltration, would be of strength and activity of locomotive power.
But, it will be asked, are there not different degrees of density and amount of structure in the same bulk, all of them compatible with health? May there not, for example, be two masses of brain, or of muscles of equal size, and yet of different degrees of power? To a certain extent this may be ; as where the fibrin of that muscular tissue, or the neurine of the nervous, is more abundantly divided by lax cellular tissue. On these known differences rests the doctrine of the temperaments. The bodies of some persons are distinguished by a predominance of the white fluids and vessels, and of the cellular and adipose tissues; whilst those of others are characterised by a greater proportion of red blood and fibrin, both in this fluid and in the muscles; and some, again, with this activity of the blood-vessel system, will have a large allowance, also, of neurine, with little intervening cellular matter; consequently, an excess of the nervous system. We must be careful, however, on this point, not to confound power with its readiness to be called into action, or its habitual activity. A man of large and massive frame of trunk and limb may be, as he often is, slow and heavy in his movements of locomotion, and averse to undertake any labour or feat requiring a display of strength, which another of less size of muscles even would readily engage in. But if once the former be roused, goaded as it were to action, he will inanifest prodigious activity and strength, such as the latter cannot by any means equal. The power was possessed, but not used; and hence its existence was perhaps denied. Size, here, is still a criterion of strength.
In like manner, a person of lymphatic temperament, with little activity of circulation, but possessing a large brain, may be often heavy, lumbering, as it were, in the process of thought and expression of ideas ; but there is still an evident vigour of thought, and rectitude of judgment, which will inspire more confidence in a discerning observer, than the quick resolve, plausible common-places of ideas, and Auency of speech of a more excitable person, who has a smaller cerebral structure. Let the first be roused, as we sometimes see really to occur, by some strong incentive, and the latent powers are rendered evident, and show themselves in great ingenuity, a forcible and convincing logic and outpouring of language, which startle even those who had long known and thought they had formed a due estimate of his mind.
In the above instances, whether it have been of muscular or mental strength, we venture to say, that the power on which the manifestation depended, will be found to be the result or inevitable concomitant of size and quantity of the peculiar and specific matter of the organ, be it either fibrin for the muscle, or neurine for the brain. And all allowances made for temperaments, and the relative activity of function dependent on this cause, size will still be the criterion.
Phrenologists cannot be accused of needless refinement, still less subterfuge, in admitting the modifications of activity caused by tem. peraments, when Dr. Sewall, for example, points out how much the same individual differs from himself in the two states of repose and excitement. That two men with brains of equal size and identical developement, the one of a lymphatic, the other of a sanguine temperament, should differ in the readiness of mental manifestations to the degree that one is slow, halting, and uncertain in the delivery of his opinions, and the other quick, connected, and pointed, is no contradiction to the principles of phrenology, unless it were shown that full time being given to the former to express himself quietly, delibe. rately, and maturely, he is found to fall short of the other in the force of his reasoning, and the variety and abundance of his proofs and illustrations.
Not more contrasted are these two persons than the two states of brain and mind of the same individual, as thus related by Dr. Sewall in his second lecture :
“ The late William Pinckney, of Maryland, whose extraordinary power in debate is universally known, when unexcited, exhibited nothing in his appearance which manifested great activity and energy of mind; but when roused by debate, his face became suf. fused with blood, his eye sparkling and animated, his carotids pulsated violently, his jugular veins became swollen, and every thing indicated that the blood was carried to the head with an impetus, proportioned to the excitement of the occasion, and his intellectual effort; and it was only during this cerebral orgasm, that his thoughts were poured forth with that fluency and power for which he was so remarkably distinguished. The same phenomena occurred, to some extent, in his private studies, whenever be fixed his mind intently on any subject for the purpose of deep investigation."
Changes, similar to the above, are experienced by nearly every man of any vigour of mind, when summoned to unwonted exertion, whether it be in public, or at his own desk. But it will hardly be alleged by Dr. Sewall, that Mr. Pinckney, when excited, acquired mental faculties other than those possessed by Mr. Pinckney when tranquil and passive, any more than that Hercules, engaged in one of his labours, can be supposed to have acquired more muscular power than he possessed when leaning quietly on his club. The faculties in the first case, and the power in the second, were constantly present; they were intimately associated with organisation ; but they were only manifested, or called into active display, under some strong excitement. It cannot be contended that the more active circulation of blood in the brain, and its greater determination to this part, are the cause of new talonts or of genius; since no proportion exists between the frequency of the former and a display of the latter. Were it so, every man in a furious passion would forthwith become a powerful reasoner, a fluent speaker, a poet, or a mathematician; and the exploding rhapsodies of poetry in favour of cerebral stimulation by intoxicating liquors, might once more obtain currency and credence. The true cause and support of mental power is the organic structure; the amount of the former corresponding with the mass and density of the latter. But the primary conditions, ard occasional means of giving activity to the power, are various. Among the chief conditions, are temperament; among the occasions, the incentives furnished by necessity, imitation, a desire to excel and govern, &c. The brains of some men are habitually in the state of orgasm which Mr. Pinckney's brain is represented by Dr. Sewall to have occasionally exhibited; whilst those of others are habitually and uniformly as quiet and relatively passive as Mr. P.'s was in common. The lecturer, in confounding power with activity and manifestation, is led to assert, that "there is something which gives power to the mind, which has no connection with the volume of the brain ;" but if a power can be thus indefinitely augmented, independently of and without increased volume, where was the necessity of any volume at all, or matter on which the volume depends, in order that power should have been originally possessed ? That which can be indefinitely extended, without any increase of its