Its circumference, measured immediately over the orbitar arch and the most prominent part of the occipital bone, is fixed by Gall, whose observations on this subject are entitled to great confidence, at between 1H and 14? inches.1 The brain consequently equals that of a new-born infant; that is, about one fourth, one fifth, or one sixth of the cerebral mass of an adult's, in the full enjoyment of his faculties. The above is the only constant character observed in the heads of idiots;—their forms are as various as those of heads of the ordinary size. When idiocy supervenes in early infancy, the head is sometimes as remarkable for immense size, as in the former case, it is for its diminutiveness. The cause of this enlargement is some kind of morbid action, preventing the developement of the cerebral mass and producing serous cysts, immense dropsical effusions, &c. In idiocy the features are irregular; the forehead low, retreating and narrowed to a point; the eyes are unsteady and often squint; the lips are thick, and the mouth being kept open, the saliva is suffered to escape, and their spongy gums and defective teeth are displayed; the limbs are crooked, and feeble and limited in their motions. The senses are very imperfect at best, and often entirely wanting. Many are deaf and dumb, or blind. Many are incapable of perceiving odors, and have so little taste as to show no discrimination in their choice of food, swallowing whatever comes to hand. Their movements are. constrained and awkward; they walk badly,

easily falling down; and are constantly dropping whatever is placed in their hands. None are able to articulate more than a few words, to which they seem to attach no meaning; while the most of them utter only cries or muttered sounds. Some make known their most important wants by means of signs or sounds, that are intelligible to those who have the care of them. Idiots are generally affected with rickets, epilepsy, scrofula, or paralysis, and their whole physical economy indicates a depraved and defective constitution. Idiocy, as above described, is congenital, or begins at a very early period, and is incurable. Its wretched subjects seldom live beyond their twenty-fifth year, continuing all their lives in the same brutish condition, utterly unchanged by external circumstances, and scarcely indicating the species to which they belong, in their stupid, brutelike countenance, in their dull or glaring eyes, gaping mouth, their wild and hideous laugh, their inarticulate sounds, their obtuse sensations, and utter unconsciousness of social and domestic relations.

§ 36. In reasoning power, idiots are below the brute. Unable to compare two ideas together, nothing leads them to act but the faint impressions of the moment, and these are often insufficient to induce them to gratify even their instinctive wants. It frequently happens, however, that some one or more of the intellectual faculties, always excepting the reflective, are manifested in more or less perfection. Among the moral sentiments, it is not uncommon to find self-esteem, love of approbation, religious veneration, and benevolence, bearing a prominent part, if not constituting the entire character, and

thus producing a slight approximation to humanity. Rush' speaks of one who was remarkable for kindness and affection, and spent his life in acts of benevolence, though he showed no one mark of reason. Dr. Combe2 saw two, who, though differing much, in other respects, agreed in evincing a strong predilection for religious worship, and for listening to sermons and prayers. Some can recollect names, numbers, or historical facts; some are capable of repeating what they have frequently heard; others are able to sing a few airs, and even to play on musical instruments. Gall3 saw one at Hamburgh, sixteen years old, who learned names, dates, numbers, history, and repeated them all mechanically, but was destitute of all power of combining and comparing his ideas, and was incapable of being engaged in any employment. Various propensities, such as the sexual feelings, cunning, and deslructiveness, they often manifest in an inordinate degree of vigor and activity.

§ 37. Jn that form of idiocy, called cretinism, which is endemic in the Alps and some other mountainous countries, opportunities of observing its phenomena are offered on a grand scale. The difference in the degrees of this affection has led to its division into three classes, viz., cretinism, semi-cretinism, and cretinism of the third degree. In the first, life seems to be almost entirely automatic; most of its subjects are unable to speak, their senses are dull, if not altogether wanting, and nothing but the most urgent calls of nature excite their attention. The semi-cretins show some glimmering of a higher nature ; they note what passes around; they remember simple events; and make use of language to express their wants. They are capable of little else, however, for they have no idea of numbers, and, though taught to repeat certain passages, they learn nothing of their meaning. The actions of those of the third kind indicate a still higher degree of intellect; they have a stronger memory of events, and they learn to read and write, though with scarcely any conception of the purposes of either. Particular talents are often displayed by them in a very respectable degree. Music, drawing, painting, machinery, &c., have each had its followers, in a humble way, among these cretins. In the construction of some parts of a watch, they are often employed in Geneva, and their work is characterized by neatness. Others have executed drawings of some merit, and some have even studied several languages, in which their acquisitions were by no means insignificant: while others have even attempted poetry, though succeeding in nothing but the rhyme. Though, in all degrees of idiocy, the intellectual powers are so deficient as hardly to be recognised, and therefore these distinctions can be of little practical importance, yet they may serve to teach us how independent of one another are the various moral and intellectual faculties, and lead us to be cautious how we infer the soundness or capacity of the whole mind, from the perfection manifested by one or two of its faculties.

CHAPTER III.

IMBECILITY.

§ 38. By imbecility is meant an abnormal deficiency either in those faculties that acquaint us with the qualities and ordinary relations of things, or in those which furnish us with the moral motives that regulate our relations and conduct towards our fellow-men; and frequently attended with excessive activity of one or more of the animal propensities. In imbecility the developement of the moral and intellectual powers is arrested at an early period of existence. It differs from idiocy, in the circumstance, that while in the latter, there is an utter destitution of every thing like reason, the subjects of the former possess some intellectual capacity, though infinitely less than is possessed by the great mass of mankind. Imbeciles can never attain that degree of knowledge which is common among people of their own rank and opportunities, though it is very certain that they are not entirely unsusceptible of the influences of education. They are capable of forming a few simple ideas and of expressing them, in language ; they have some memory and a sense of the conveniences and proprieties of life. Many of them learn to read, write, and count, and make some progress in music, though for the most part, they