of the membrane with the choroid plexus, and its prolongation across the aqueduct of Sylvius and the foramen of Monro, has been established.

6. În the interval between the two lamina, which, by facing each other, form the septum lucidum, it is easy to demonstrate the existence of the fifth ventricle, and its communication with the third.

7. The pituitary body is canaliculated.

8. The anterior orifice of the aqueduct of Sylvius was found obliterated in the two cases where it was examined: the cerebral cavities being thus completely closed.

9. The absence of all softening of the cerebral substance, and the very slight plasticity of the fluid effused, discountenance the idea of chronic hydrocephalus being the result of inflammation. In the opinion of M. Blache it is a simple dropsy.

Chronic hydrocephalus is not a very frequent disease in Philadelphia. In a practice of fifty years we have seen but two congenital cases, and only one in which the disease was developed subsequent to birth.

In the treatment of chronic hydrocephalus, our chief object must be to palliate the symptoms as they occur, by the occasional application of leeches, and the use of repeated blisters, the tartar emetic ointment or issues. The bowels should be kept regularly open by gentle aperients, and the diet of the patient carefully regulated. Mercury has been strongly recommended, and is deserving of a fair trial.

The radical cure of the disease has been attempted, by properly regulated and continued pressure applied to the head; cases of success from this plan of treatment have been published by Blane, Barnard, Engleman, and others. The plan in favor of the feasibility, safety, and success of which, the greatest amount of evidence has been adduced, is that of drawing off the effused fluid by puncturing the brain, and preventing its re-accumulation by pressure applied round the head.

The operation consists in passing a small and delicately constructed trocar into one of the lateral ventricles, and drawing off as much fluid as the powers of the constitution will admit of. The most eligible spot at which the trocar can be introduced is in the course of the coronal suture, about midway between the crista galli process of the ethmoid bone, and the anterior fontanelle, so that the danger of wounding the corpus striatum is avoided on the one hand, and the longitudinal sinus on the other. The instrument usually penetrates about two inches, and in most cases the serum discharged is colorless, but occasionally it is tinged with blood. Sometimes on withdrawing the trocar, the water will not flow until a probe has been passed along the canula, to remove portions of brain which block it up. After taking away all the fluid that can be done consistently with safety, the head which has been steadily compressed by an assistant during the operation must be strapped with adhesive plaster, so as to retain its diminished size, and avert the fearful consequences of suddenly removing from the brain the long-continued pressure to which it has been subjected. Cases of a successful result from puncturing the brain in chronic hydrocephalus are reported by Schoepf, Mérei, Lagre (Révue Médico-Chirurg., tom. vi.), Whitney, Ketsell (Amer. Jour. Med.

Sciences, 1843, 1850), and Edward (Edin. Month. Journal, 1846). There is reason to believe, however, from a careful analysis of all the cases on record in which the operation has been performed, that its successful results have been greatly overrated. In no instance has it been clearly shown that a well-marked congenital case has been permanently benefited. The cases in which the operation has been most successful, according to Conquest, are those in which the effusion has manifestly resulted from an inflammatory condition of the brain, and in which cerebral excitement follows the operation.

It is proper to remark, however, that even in these, the operation has been found unsuccessful in the larger number of instances; it has been pronounced by high authority (Gölis, Heister, Hecher, Portenschlag, Fergusson) as one that is in all cases both cruel and useless.

8. Chorea.

Chorea is a very common disease of childhood, occurring more frequently between the eighth and fourteenth years, than at any other period of life. It consists in involuntary convulsive movements of the voluntary muscles, particularly of the face and extremities, and occasionally of those of the neck and trunk. In some cases, nearly the whole of the voluntary muscles are more or less affected with convulsive or irregular movements; in others, these are confined to one side, to the face or neck, or to a single extremity.

The distinguishing characteristic of the disease is an incomplete subservience of the muscles of voluntary motion to the will, in consequence of which their actions are rendered irregular and uncertain. Thus, the patient intending to approach a cup of water to his lips, will involuntarily cast it from him, or throw its contents over his shoulder; or, in attempting to advance his foot forward, in the act of walking, carries it in every possible direction excepting the right one. The movements of the face, arms, and hands often resemble the gesticulations of buffoonery.

The name of the disease (Chorea Sancti Viti-the Dance of Saint Vitus) is derived from the circumstance of the patients affected with it formerly repairing annually to the chapel of St. Vitus, near the city of Ulm, in Swabia, where they danced day and night, as a means of effecting their cure.

Chorea affects children of both sexes, but more frequently girls, particularly those of a weakly constitution, or whose health and vigor have been impaired by confinement, impure air, improper or deficient nutriment, or preceding disease.

Previous to its occurrence, the patient is, in general, affected with the ordinary symptoms of derangement of the digestive organs—a depraved, variable, or defective appetite, tumid abdomen, constipated bowels, and a loss of his previous vivacity and playfulness.

The attack in general commences with slight, irregular, involuntary movements of different muscles, particularly those of the face, which are often mistaken for voluntary grimaces; these, after a shorter or longer period, are succeeded by the more constant and general move

ments by which the disease is characterized. Any one set, or all of the muscles of voluntary motion, may be affected in different cases. Usually there is an unsteadiness in the patient's gait, which is marked, often, by a peculiar jumping or starting movement; or one leg will be dragged along, in place of being lifted in the usual manner; while the arms are moved about, as if the patient were performing various intentional gesticulations. He is often unable to perform the common and necessary movements with the affected arm, the involuntary action of the muscles entirely counteracting those directed by the will. These convulsive movements are more or less violent, and are often constant while the patient is awake; during sleep, in most cases, they cease entirely. Occasionally different muscles become successively affected, yet in the generality of cases, it is in those first attacked, that the convulsive movements remain throughout the disease.

In consequence of the affection of the muscles of the tongue and throat, in some instances, articulation and deglutition are impeded or performed with difficulty. Two cases of chorea are referred to by Romberg (Diseases of the Nervous System), the only ones he had ever met with, in which the muscles of the external and internal respiratory apparatus were involved. In one of these cases, a child eight years of age, the choreic movements of the right half of the body were associated with dyspnoea, whistling inspiration, and palpitation. In the second case, a boy of eight years, only the muscles of the extremities, the face, and the eyes, were at first attacked; subsequently, the choreic movements ceased in these parts, and the muscles of respiration became affected.

In extreme cases of chorea, the eyes lose their lustre and intelligence, the face becomes pale, and the expression of the countenance is that of vacancy, indifference, and languor. The mouth is often distorted, so as to give to the face the appearance of a habitual silly grin. The patient acquires, in fact, the features of idiocy. In a few cases, indeed, when the disease has continued for a length of time, partial or even complete fatuity has been known to ensue. This, however, is by no means a very common sequel of chorea, even in its most violent and chronic forms. Many instances are on record, and similar ones have fallen under our own notice, in which the disease has continued, with but slight intermissions, from childhood to an advanced age, without the integrity of the intellect being much, if at all, impaired. In some cases, the patients are affected with a species of melancholy, or with the peculiar nervous temperament that commonly accompanies hysteria.

Throughout the attack the bowels are generally costive, and the appetite defective, capricious or ravenous. Febrile reaction is not necessarily an attendant upon chorea, and when it does occur, is generally the result of gastro-intestinal irritation or some accidental affection. When the disease is very violent and protracted there in general occur great emaciation, a flaccid state of the muscles. great depression of strength, paleness and discoloration of the skin, and the other indications of impaired energy of the digestive and nutritive functions.

Pain, remarks, Dr. Churchill, is seldom complained of by patients affected with chorea, and but little general distress. Out of twenty cases related by Dufossé, eight suffered from slight headache, six from palpitations, and two from a pain, increased by pressure upon the spinous processes. Richard states that most of the girls he has seen affected with the disease presented a lateral curvature of the spine, and he seems inclined to attribute the chorea to an overstretching of the nerves.

The heart is, according to Dr. Todd (Lumlean Lectures, 1849), very frequently morbidly affected in chorea; and this morbid affection shows itself, not in. any disturbance of the rhythm of the heart, which, so far as his observation extends, never is affected, but in a derangement of its sounds. A bellows sound is frequently found, and is either aortic, systolic, when it is almost always an accompaniment of the anæmic state of the patient, or, much more frequently, mitral, systolic, or regurgitant. This condition of the cardiac sounds in chorea was described by Dr. Todd in the Croonean Lectures on the pathology of rheumatism in 1843. But to Dr. Addison, of Guy's Hospital, is due the merit of having first made known the morbid condition of the sounds of the heart in this disease.

Epilepsy and hemiplegia are not uncommon results of chorea. In many of the cases that have fallen under our notice the patients have died from tubercular meningitis-the lungs and serous tissues of the thorax and abdomen exhibiting, also, tubercular depositions.

According to Dr. Todd, the choreic convulsion is frequently suc ceeded by a paralytic state of the limbs previously convulsed; the paralysis is seldom complete, although considerable. When the choreic convulsion has affected one side, the paralysis will likewise affect the same side; it will be hemiplegic, and will resemble very closely hemiplegia from diseased brain, for which it is very apt to be mistaken by those not aware of the fact. We have occasionally met with this paralytic state as a consequence of violent attacks of chorea, but have not found it so common a sequel of the disease as stated by Dr. Todd.

Chorea has been defined by some writers to be an irregular motion of the muscles, when excited into action by the will; the disease consisting in a loss of the power of volition over their mode of actionthat is, of directing and combining their action, for the accomplishment of any particular movement. The disease, has, consequently, been supposed to result from some lesion of the cerebellum. This definition would, however, exclude a number of cases, in which the convulsive movements of the muscles certainly occur independently of the will, and unassociated with consciousness, differing from convulsions only in the orderly nature of the motions. Such are cases of malleation, in which the convulsive paroxysm consists, principally, in a constant striking the knees with one or both hands, as with a hammer; or of rotation of the whole or a part of the body, as in the case described by Watt, in an early volume of the Medico-Chirurgical Transactions. In this case the patient, a girl ten years of age, was seized with an irresistible propensity to turn round on her feet like a top, then to lie down, and roll rapidly backwards and forwards. In

a more advanced stage of her disease, while lying upon her back, she would bend herself up like a bow, by drawing her head and heels together, and then suddenly separate them, so as to cause the buttocks to fall with considerable force upon the bed; and repeat this continually, for hours. At a still later period she was seized with a propensity to stand upon her head, with her feet perpendicularly upwards. As soon as her feet gained the perpendicular all muscular action ceased, and her body fell as if dead, her knees first striking the bed, and her buttocks striking her heels; this was no sooner done than she instantly mounted up as before, and continued these evolutions, sometimes for fifteen hours consecutively, at the rate of twelve to. fifteen times in the minute. Rufz mentions a case in which the child threw itself out of bed, and crawled about the room like a worm.

To this same class belong also the salaam convulsions, noticed in a previous section. But it would be impossible to describe all the various forms under which the disease occasionally presents itself; in many, no description can convey an adequate idea of the odd appearance and strange gesticulations of the patients; so that it is not at all surprising that in times of ignorance and superstition the disease was ascribed to supernatural causes, and the agency of demons. It is more than probable, as remarked by Carpenter, that many cases of stammering are to be regarded as a species of chorea of the muscles of the voice.

Allied to the movements of chorea, remarks Dr. Todd, are the fidgets of children, and perhaps, also, those of grown persons. In some children, these fidgety movements are so excessive, that the child becomes almost a nuisance. All the muscles are affected; the child incessantly makes grimaces of the most various kinds; every minute he assumes a new attitude; if anything comes in his way, he must handle or touch it; these irregularities are always the greater when there is derangement of the general health. Children thus affected might readily be thrown into the convulsions of chorea by a strong mental emotion. It is very possible, remarks Dr. Churchill (Diseases of Infants and Children), that while some cases of stammering may in fact be a vocal species of chorea, the same is true also of those cases of incessant winking or twitching of the nose or mouth, which we meet with occasionally, and which are so difficult to cure, although they often get well. I have, he adds, at this moment under my care a little boy, very nervous, but healthy, who ordinarily winks about twice as often as other children, but if it be noticed, or if he be unu sually earnest about anything, the eyelids are in incessant motion, and closed with unusual force.

In 429 cases referred to by Dufossé and Rufz, 130 occurred in boys, and 299 in girls. If I may trust to my own experience, says Dr. Watson (Lectures on Practice of Physic), it is much more common in children having dark hair and eyes, than in those of a light complexion; and I think I have seen the same remark in some book, but I forget where. But, according to W. H. Bell (Dict. des Etudes Médicales), Dufossé (ibid.), and Rufz (Archives Générales de Méd.), the subjects of chorea have chiefly light hair. It usually occurs, as already