Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/107

 INSANITY 97 ness of relationship in tracing hereditary predisposition, mainly from the fact that it frequently skips a generation. As a rule it does not confine itself to a single individual of a family, but makes itself felt in one form or another in several members. According to Esquirol and Baillarger, it is more frequently transmitted through the female than through the male branch, but this opinion is called in question by Koch of Wiirtemberg, whose statistics show that hereditary tendency to insanity acts more strongly through the father than through the mother. CONGENITAL INSANITY. The morbid mental conditions which fall to be considered under this head are Idiocy (with its modification Imbecility} and Cretinism. Idiocy. In treating of idiocy it must be carefully borne iu mind that we are dealing with mental phenomena dis associated from active bodily disease, and that, in whatever degree it may exist, we have to deal with a brain condition fixed by the pathological circumstances under which its possessor came into the world, or by such as had been present before full cerebral activity could be developed, and the symptoms of which are not dependent on the interven tion of any subsequent morbid process. From the earliest ages the term Amentia has been applied to this condition, in contradistinction to Dementia, the mental weakness following on acquired insanity. The causes of congenital idiocy may be divided into four classes: (1) hereditary predisposition, (2) constitutional conditions of one or both parents affecting the constitution of the infant, (3) injuries of the infant head prior to or at birth, and (4) injuries or diseases affecting the infant head during infancy. All these classes of causes may act in two directions : they may produce either non-development or abnormal development of the cranial bones, as evidenced by microcephalism, or by deformity of the head ; or they may induce a more subtle morbid condition of the con stituent elements of the brain. As a rule, the patho logical process is more easily traceable in the case of the last three classes than in the first. For instance, in the case of constitutional conditions of the parents we may have a history of syphilis, a disease which often leaves its traces on the bones of the skull ; and in the third case con genital malformation of the brain may be produced by mechanical causes acting on the child in utero, such as attempts to procure abortion, and deformities of the ma ternal pelvis rendering labour difficult and instrumental interference necessary. In such cases the bones of the skull may be injured; it is only fair, however, to say that more brains are saved than injured by instrumental inter ference. With regard to the fourth class, it is evident that the term congenital is not strictly applicable ; but, as the period of life implicated is that prior to the potentiality of the manifestation of the intellectual powers, and as the result is identical with that of the other classes of causes, it is warrantable to connect it with them, on pathological principles more than as a mere matter of convenience. Dr Ireland, in his work On Idiocy and Imbecility, classi fies idiots from the standpoint of pathology as follows : (1) Genetous idiocy : in this form, which he holds to be complete before birth, he believes the presumption of here dity to be stronger than in other forms ; the vitality of the general system is stated to be lower than normal ; the palate is vaulted and narrow, the teeth misshapen, wrongly placed, and prone to decay, and the patient dwarfish in appear ance ; the head is generally unsymmetrical, and the com missures occasionally atrophied ; (2) Microcephalic idiocy, a term which explains itself ; (3) Eclampsic idiocy, due to the effects of infantile convulsions ; (4) Epileptic idiocy ; (5) Hydrocephalic idiocy, due to water on the brain ; (6) Paralytic idiocy, a rare form, due to the brain injury causing the paralysis ; (7) Traumatic idiocy, a form pro duced by the third class of causes above mentioned ; (8) Inflammatory idiocy ; (9) Idiocy by deprivation of one or more of the special senses. Dr Ireland s wide experience has enabled him to differentiate these groups further by describing the general characteristics, mental and physical, of each. The general conformation of the idiot is often very imper fect ; he is sometimes deformed, but more frequently the frame is merely awkwardly put together, and he is generally of short stature, Only about one-fourtli of all idiots have heads smaller than common. Many cases are on record in which the cranial measurements exceed the average. It is the irregularity of development of the bones of the skull, especially at the base, which marks the condition. Cases, however, often present themselves in which the skull is perfect in form and size. In such the mischief has begun in the brain matter. The palate is very often highly arched, in some cleft ; hare-lip is not uncommon ; in fact congenital defect or malformation of other organs than the brain is more commonly met with amongst idiots than in the general community. Of the special senses, hearing is most frequently absent. Sight is good, although coordina tion may be defective. Many are mute. On account of the mental dulness it is difficult to determine whether the senses of touch, taste, and smell suffer impairment; but the impression is that their acuteness is below the average. It is needless to attempt a description of the mental phenomena of idiots, which range between utter want ot intelligence and mere weakness of intellect. The term Imbecility has been conventionally employed to indicate the less profound degrees of idiocy, but in point of fact no distinct line of demarcation can be drawn ; the application of either term to a given case depends more on the opinion of the observer than on the condition of the observed. As the scale of imbeciles ascends, it is found that the condition is evidenced not so much by low obtuse- ness as by irregularity of intellectual development. This serves to mark the difference between the extreme stupidity of the lowest of the healthy and the highest form of the morbidly deprived type. The two conditions do not merge gradually one into the other. Extreme stupidity and sottish ness mark many cases of idiocy, but only in the lowest types, where no dubiety of opinion can exist as to their nature, and in a manner which can never be mistaken for the dulness of the man who is less talented than the average of mankind. Where in theory the morbid (morbid in the sense of deprivation) and the healthy types might be supposed to approach each other, in practice we find that, in fact, no debatable ground exists. The uniformity of dulness of the former stands in marked opposition to the irregularity of mental conformation in the latter. Com paratively speaking, there are few idiots or imbeciles who are imiformly deprived of mental power; some may be utterly sottish, living a mere vegetable existence, but every one must at least have heard of the quaint and crafty sayings of manifest idiots indicating the presence of no mean power of applied observation. In institutions for the treatment of idiots and imbeciles, children are found not only able to read and write, but even capable of applying the simpler rules of arithmetic. A man may possess a very considerable meed of receptive faculty and yet be idiotic in respect of the power of application ; he may be physically disabled from relation, and so be manifestly a deprived person, unfit to take a position in the world on the same platform as his fellows. Dr Ireland subdivides idiots, for the purposes of education, into five grades, the first comprising those who can neither XIII. 13