This successive and gradual order of development, stationary state, and failure, is the cause, and serves to explain, why, in the new-born infant, the only functions are those of the senses of voluntary motion, the expression of the want of nourishment, and of obscure sensations of pleasure and pain, desire and aversion; why all this takes place only to an imperfect degree; why the infant begins, by degrees, to attend to external objects, to act on them, to manifest determinate desires and propensities; how the impressions are preserved, and how these impressions become ideas and notions; how the qualities and the faculties, begin to act and to manifest themselves under the image of different talents as well as different propensities; for example, love, friendship, vanity, ambition, pride; how the infant becomes successively a child, a young man and an adult; how, at this period, all the moral and intellectual forces of the man have acquired their greatest energy, up to the moment when they begin to fail, and to lose insensibly more or less of their permanency and activity; in fine, how in old men there remain only blunted sensations, and weakness of mind. We see, clearly, by this succession of development, that the faculties of the mind and soul, and their manifestation follow, step by step, the state of their material conditions. The progression of the functions is the same as that of the organs. Nothing can show more evidently, that the manifestation of these faculties depends on the organization. 2. When the development of the organs of the moral qualities and intellectual faculties does not follow its usual order, the manifestation of the functions of these organs likewise departs from its usual regular progress. We frequently observe in the rickets, that the intellectual faculties of children are more lively, than their age would warrant. The reason is, that one of the or dinary effects of this malady, is to give the brain an extraordinary degree of development and of irritability. Sometimes, indeed, a particular part of the brain is developed prematurely, without there being any disease to occasion it; and, in this case, the function proper to this part fails not to manifest itself at the same time. We have, for example, observed several children, in whom the part of the brain appropriated to physical love, had acquired an extraordinary development at the age of three or four years. These children were mastered by this unhappy propensity, although their sexual parts, even when they experienced some excitement, had rarely acquired an analogous development. Other children, in whom the same organization was remarked, manifested the phenomena of complete virility, while the other faculties were still undeveloped. I shall, elsewhere, cite several similar facts relative to the organs of each faculty. Does it happen that the different parts of the brain, or the totality of the organ, acquire their maturity and their solidity only at a very late period? The state of infancy and of half imbecility then prolongs itself to the age of from six to twelve years. But, at this period, nature seems to labor with new energy, for the development of the parts; and children from whom, until this moment, no capacity had been expected, become, in a short time, remarkable for their talents. This was the case with Gesner, one of the best and most amiable poets of Switzerland. Born of a family in which rickets were hereditary, his instructors, when he had attained the age of ten years, declared him entirely incapable of making any progress. One of the most distinguished physicians of Berlin could not, till his thirteenth year, combine his ideas nor make use of the organ of language. The simultaneousness of the manifestation of particular functions, and of the irregular, precocious or late development of their organs, is, therefore, a constant phenomenon which cannot be called in question. Now it necessarily results from this phenomenon, that the ex ercise of the qualities of the mind and soul depend on material organs. 3. If the development and the perfection of the cerebral organs has not been complete, the manifestations of the respective qualities and faculties remain equally incomplete. Although the energy of the functions of organs does not depend solely on their development, but also on their excitability, we may yet determine with confidence the degree of development of the brain necessary to its functions. The observations of all ages have established, that the brain is incapable of fulfilling its destiny, when its bony case or the cranium has only from thirteen to seventeen inches in circumference, the measure being taken on the most prominent part of the occiput, passing over the temples and the most elevated part of the forehead. Willis has described the brain of a young man, simple from birth its volume hardly equals the fifth part of that of an ordinary human brain. I have had a copy drawn after Willis in my large work. (Pl. XVIII. fig. 2.) M. Bonn, professor at Amsterdam, possesses two little skulls of idiots, and the brain of a simpleton who lived to the age of twenty-five years. (Pl. XX. fig. 1.) He was so stupid, that, though born at Amsterdam, they made him pass for an African savage, and exhibited him for money. M. Pinel has a similar cranium of a young girl of eleven years, perfectly idiotic. Among the anatomical preparations of the school of medicine at Paris, is also found the undeveloped cranium of an idiot child. I have had two similar skulls drawn, taken from my collection; both are remarkable for their smallness;* one is the skull of a child of seven years; * Pl. XVIII. fig. 2. the other* of a girl of twenty. These two individuals were perfectly imbecile. I have observed heads equally small, in several congenital idiots, still living. All these skulls and heads are from thirteen to fourteen inches in circumference, and eleven to twelve from the root of the nose to the great occipital foramen. If dwarfs, who enjoy their intellectual faculties to a certain degree, appear to form an occasional exception to this law, the size of the head has not been duly noticed, which, in these cases, is always very disproportionate to the rest of the body. Even when the head is a little larger than those which characterize complete imbecility, the intellectual faculties are still almost entirely benumbed. In the different degrees, which characterize imbecility, the faculties manifest themselves in the same proportion as the brain becomes more perfect in its organization. Individuals, who are in this degree of development, exhibit some peculiar dispositions and propensities; their gestures become more significant; they go so far as to produce short phrases sufficiently well followed out. The functions thus elevate themselves together with the organization, until the feebleness of the mind betrays itself in a small number of points, or even in a single point. We see, by this, that all individuals who are reputed simple, are not completely so. Parents and physicians sometimes have trouble in comprehending how a child, who acquits himself well in all there is to do in the house, and who exhibits exact sensations, sensibility, and even cunning, can be ranged in the class of simpletons. Such is, notwithstanding, the state of many children, who hear, but do not learn to speak. I have directed my attention to this point, while occupying myself with the functions of the sense of hearing;† and when I treat of the articulate language peculiar to man, I shall show that this accident has for its cause an organic * Pl. XIX. fig. 1 and 2. + Anat. et Phys. du Cer. T. 1. s. 6. malady of the brain, and a consequent want of power to exercise all its functions. At Hamburg, we saw a young man of sixteen, in whom the anterior-inferior parts of the head were well developed; but his forehead was hardly an inch in height, because the anterior-superior parts had been checked in their development; and he enjoyed, in consequence, only the exercise of the functions belonging to the anterior-inferior portion. He learned names, dates, numbers, history, and repeated it all mechanically. But combination, the comparison of ideas and judgment, were entirely wanting. They regarded him with reason as simple, and could employ him in nothing. I shall have occasion in the course of this work, to cite several examples which confirm the proposition, that the defective development of the brain, or of particular organs, has always for its result the feebleness of their action. 4. When the organs of the mind and soul have acquired a high degree of development and perfection, there results to these organs, a power of manifesting their functions with great energy. I shall prove the truth of this result, when I treat of the influence of the development of organs on the excise of the corresponding faculties. I shall show, at the same time, that when individuals distinguish themselves peculiarly, and in a remarkable manner, by a determinate quality, or when they fall into a fixed idea, propensity, partial mania, or monomania, by too great exaltation, it is almost always the extraordinary development of some particular organ which occasions it. Without now entering into these details, I shall content myself with fixing the attention of my readers on the manifest difference which every one may remark between three sorts of heads, to wit: the heads of idiots, the heads of men whose talents are only moderate, and those of illustrious men, of vast and eminent genius. The first are |