rior columns. The general result of this experiment is, that any change that takes place in the state of sensibility-either an increase or a diminutionshows itself everywhere, at the same time, behind the section.

Other questions discussed have reference to the transmission of the various sensitive impressions-touch, pain, temperature, muscular contraction, &c.— and of the orders of the will to muscles. Dr. Brown-Séquard thinks that each kind of sensitive impression requires a distinct conductor. With respect to voluntary movement, he is of opinion that the idea of two columns of the spinal cord (the anterior) alone employed in the production of these movements, must be abandoned, and that it is extremely probable that the true conductors pass in the anterior pyramids, and, after having made their decussation, pass chiefly in the lateral columns of the spinal cord and in the gray matter near these columns, and, at last, after a short distance, a number of these conductors leave the lateral columns to pass into the gray matter and into the anterior columns.

Lecture V.-This lecture is occupied chiefly with pathological cases which show that the transmission of sensitive impressions is chiefly through the gray matter of the cord, and not along the posterior columns. One case is this:CASE 14.-J. C æt. 44, admitted into St. Bartholomew's Hospital for paraplegia. The patient was lifted into a chair, and when thus sitting, he did succeed, by a great effort, in raising his legs from the ground; but afterwards the inability of motion became complete through each lower limb in its entire extent. There was no discoverable impairment of sensation in any part of the limbs; on scratching, pricking, and pinching the skin nowhere was any defect of feeling acknowledged by the patient. In the upper limbs there existed no defect either of motion or sensation.

Autopsy. The spinal cord was the only seat of disease; membranes healthy. The posterior half, or columns of the cord, throughout the entire length, from the pons to the other end, was of a dark-brown color, extremely soft and tenacious. The anterior half exhibited its natural whiteness and firm consistence. The roots of the spinal nerves were unaltered; the brain was healthy. (Mr. Edward Stanley, in ‘Medico-Chirurgical Transactions,' 1840, vol. xxiii. pp. 83-84.)

Lecture V1.-In this lecture, which is a continuation of the former, we have also some very important cases. Of these this is one :

CASE 22.-A man, æt. 44, after having had cramps, formication, and weakness in the lower limbs, and paralysis of the upper limbs, for a long period, was admitted at the Charité. Sensibility existed everywhere. On the evening of the 1st of November he was able to walk with aid of some one. Sensibility remained everywhere to the last moment before his death, on the 3d of Novem ber, at three A. M.

Autopsy-Encephalon normal. There is an induration of the spinal cord from its upper extremity to the third dorsal vertebra, and from the sixth dorsal vertebra to the lower extremity. The tissue of the cord in these parts being cut, was shining, looking like porcelain, hard and difficult to be crushed. The gray matter was also a little harder than normal, but of its usual color. The anterior and posterior roots seemed normal. In the space between the third and sixth dorsal vertebræ the cord was softened, pultaceous, resembling a whitish or rather slightly rose pulp (bouillie), punctuated in some places. Put in water, many parts became disintegrated, and formed a kind of emulsion. This alteration existed only in the white substance; the gray, on the contrary, seemed to have preserved its normal consistence. The microscope showed that the gray matter in both the softened and the indurated parts contained normal cells and fibres, and normal blood vessels, while the white substance in the softened region contained but rare fibres, which were altered, containing an oily matter and granulations. There was also a quantity of granulated corpuscles of inflammation, with many capillaries, oily drops, and amorphous matter. In the indurated white substance there was less alteration, and the fibres were more normal and numerous. (Laboulbène, in Mémoires de la Société de Biologie,' for 1855, pp. 233-45.)

The author of the report of this case adds, that he has ascertained that sen

sibility to pinching, pricking, touching, and tickling, and the feeling of cold, and that given by a muscular spasm due to galvanism, have persisted in this patient, although the white matter, i. e., the posterior and the antero-lateral columns, had but few, and only altered fibres. A capital point in this case was the conservation of the gray matter with the persistence of sensibility.

Summing up the pathological evidence it is found, 1st, that there are many cases of alteration only, or almost only, limited to the gray matter, in which both voluntary movement and sensibility are lost; and, 2dly, that there are many cases of deep alteration of all the white substance of the spinal cord, the gray matter remaining normal, in which sensibility persisted.

Lecture VII.-In this lecture Dr. Brown-Séquard relates cases which show that the conductors of sensitive impressions from the trunk and limbs decussate in the spinal cord, and not in the encephalon, and that the conductors of the orders of the will to the muscles decussate in the lower part of the medulla oblongata, and not in the pons Varolii.

Of cases proving the existence of a decussation of the conductors of sensitive impressions in the spinal cord, these are very remarkable:

CASE 29.-A patient was admitted into the St. André Hospital. He had paralysis of voluntary movements in the right side of the body, in which sensibility was preserved. In the left side, on the contrary, the voluntary movements existed, but there was a great diminution of sensibility.

Autopsy. There was a fungoid growth (végétation fungoide) pressing upon the right lateral half of the spinal cord. (Mémoires de la Société de Biologie' for 1854.)

CASE 30.-A patient had lost voluntary movements in the two limbs of the left side, in which sensibility was preserved. In the right side sensibility was much diminished (très obtuse).

Autopsy. A clot was found in the left lateral half of the spinal cord in the cervical region. ('Mémoires de la Société de Biologie' for 1854.)

These two cases are extremely valuable, and they agree perfectly with the results of experiments on animals. It is so also with the following cases:CASE 31.-A man, after having felt a sudden pain in his back, became incompletely paralyzed of voluntary movements in the right lower limb. Sensibility was not altered in this limb, but in the left side, where voluntary movements were not impaired, sensibility was entirely lost from the breast to the foot.

Autopsy-Brain and its membranes normal. In the spinal cord an hemorrhage had taken place, and blood was found in the right side of the gray matter, having destroyed also its horns, and a part of the left anterior column in the dorsal region. (Monod, in 'Bulletin de la Société Anatomique,' No. XVIII, p. 349, Obs. 3, and in Ollivier, loco cit., vol. ii. p. 177.)

This is a very remarkable case, teaching, not only that there is a decussation of the conductors of sensitive impressions in the spinal cord, but also that the gray matter is the principal channel for these impressions.

In the three preceding cases there is no mention of hyperesthesia, although it must have existed on the side of the injury in the spinal cord; we shall find it mentioned in the following cases, and especially in the next one, which we give almost in full, on account of its extreme importance:

CASE 32.-On the 4th of February, 1850, a man, æt. 58, was admitted into the St. Louis Hospital, in Professor Nélaton's ward, a short time after he had been wounded by a police officer. Besides a slight wound of the scalp, he had been wounded by a sword in his back. The point of the sword was eight millimeters large; there was a transversal wound about one centimeter and a half (half an inch) between the ninth and tenth dorsal vertebræ, and three centimeters (an inch) from the line of the spinous processes. A physician, who had seen the patient at once, had introduced a stylet in the wound, and ascertained that its direction was oblique from the right to the left, and a little upwards. The patient complains of slight pains only near the wound. The lower limbs are completely deprived of voluntary movements. The next morning a better examination is made; the patient has not slept; he has suffered violent pains, principally in the left lower limb; he feels a kind of burning and numb

ness as if he were receiving electric shocks. The sensibility of the left lower limb is quite evidently increased. When a hand is simply applied upon this limb, the pains become very acute, and the very least pressure makes him shriek out. This morbid state of sensibility exists in the whole length of the limb, and also upon the left side of the sacrum and coccyx, and the upper and anterior part of the thigh. Higher up sensibility is normal. Even cold air, when the sheet is drawn down, causes pain in the left lower limb. Voluntary movements are impossible in all this limb, except in the toes, which may slightly

move.

The right lower limb has a diminution of sensibility; the patient knows when he is touched, but when pricked with a pin he does not feel pain, and he does not distinguish a pressure by the finger from the pricking of a pin. In both cases he has only a sensation of contact. This limb is not deprived of movement as it was on the previous day. The flexion of the foot on the leg, and of the leg on the thigh, are executed; the movements are extensive, but the patient cannot altogether lift up his limb from the bed.

The temperature of the lower limbs is the same as that of the rest of the body, and there is no difference between them. All the organic functions are in a normal condition, except that there is a retention of urine and of the fecal matters. Voluntary movements and sensibility are not altered in the abdomen, and all the upper parts of the body. In the afternoon the hyperæsthesia has gone a little higher on the left side in the upper parts of the abdomen, and the genital organs have also become very sensitive. When a cloth that has been dipped into water at 30° (probably centigrade, 86° Fahr.), is applied to the left limb, the patient has a feeling of burning, which makes him cry out. When the cloth has been dipped into water at the low temperature of the room, the patient has a very acute feeling of cold.

On the right limb the wet cloth does not give either a sensation of warmth or cold, or of dampness or dryness, although he feels he is touched. The tickling of the right foot is not felt as tickling, and only as a contact. On the left foot tickling is exceedingly painful.

Gradually this patient became more and more able to move the right limb, and partly also the left limb. The hyperesthesia diminished, particularly in the upper parts of the left limb; but the right limb became, for a time, unable to feel the contact of a hand, and if pricked there was a sensation, but the patient did not know its place. On the 20th of February, a slough was found on the right side of the sacrum; the patient had not felt anything there. In April, voluntary movements had returned in the two limbs, but sensibility was still deficient in the right one. On the 15th of June, the patient could walk with the help of a cane, and he left the hospital, not having yet, however, recovered entirely the power of feeling in his right limb.

Three years afterwards the patient was seen again, and he stated then that he was quite well, and that he could walk without difficulty or fatigue; but a year later, having walked a distance of many leagues he found a large scar, produced, he said, by the friction of his pants on his right knee; he had felt no pain, and was surprised when he found this wound. Although sensibility was still deficient in this limb, all its movements were executed freely, and without fatigue. (Viguès, in Moniteur des Hôpitaux,' Sept. 3d, 1855, p. 838.) After the cases of alteration of a lateral half of the spinal cord, Dr. BrownSéquard relates cases of alteration of a lateral half of the medulla oblongata, pons Varolii, &c., cases offering proof of the decussation of the conductors of sensitive impressions in the spinal cord from another point of view. This case is one of these, and a very important one :

CASE 38.-S. G, æt. 28, was, on the 14th of May, suddenly seized with an acute pain in the right side of the head, and fell down in a state of insensibility, remaining so for twenty-four hours. On recovering, she found she had lost the power of moving her left arm, and, in a great degree, that of moving the leg of the same side. The right side was unaffected, except the face, the muscles of which were paralyzed; those of the left side of the face retained their power. Sensibility of the left side of the body was destroyed, and likewise that of the right side of the face. She could not hear with the right ear.

The right eye became inflamed several weeks before her death, and the cornea was slightly ulcerated; the upper eyelid was constantly raised. Her muttering was scarcely intelligible; paralysis of all the parts affected became complete; deglutition and mastication performed with great difficulty.

Autopsy, twelve hours after death.-A fibrous, semi-cartilaginous tumor was found on the right side of the tuber annulare and the medulla oblongata, seated in the substance of the dura mater and other membranes. It extended from the point where the fifth pair of nerves arises from the tuber annulare, covered the origin of this nerve and the whole of the right side of the tuber below this, and passed down along two-thirds of the medulla oblongata, and adhered to the right side of the basilar artery. The right vertebral artery was inclosed in the tumor, which was about two inches long. The surface of the root of the right crus cerebelli on which it pressed was softened, as was also that part of the tuber annulare on which it lay. It was incorporated with the substance of the right side of the medulla oblongata, and had produced softening as far as it reached. This softening extended through the posterior tract, but became less as it approached the posterior surface. The anterior tract was a pulpy mass. Neither the anterior nor the posterior tract of the left side was perceptibly affected. The tumor pressed upon the roots of the fifth, seventh, eighth, and ninth pairs of nerves. (S. Annan, in the American Journal of the Medical Sciences,' vol. ii. July, 1841, p. 105.)

Upon this case Dr. B.-Séquard says:

"We think that the case of Dr. Annan, if we take into account the extent of the injury in the medulla oblongata, bears out clearly that most if not all of the conductors of sensitive impressions from the trunk and limbs make their decussation in the spinal cord. But the importance of this case is not limited to this demonstration: it shows at once the radical difference between the symptoms of an alteration of a lateral half of the medulla oblongata above the crossing of the pyramids, and an alteration of a lateral half of the spinal cord either in the cervical or in another region. In this last case, as we have shown a moment ago, there is loss of movement in one side and loss of sensibility in the opposite side; while in a case of alteration above the crossing of the pyramids we find that the loss of movement and of sensibility are both in the opposite side. This case is also excellent to show that the functions attributed to the restiform body as a conductor of sensitive impressions, and to the cerebellum as either a centre of perception of these impressions, or as a regulator of our voluntary movements, or as a centre for the guiding sensation, whether by a reflex action or otherwise, are not performed by these parts, as the communication between the cerebellum and the right side of the body through the right side of the medulla oblongata was almost impossible, a small part of the right restiform body remaining, and sensibility and voluntary movements being preserved in this side."

Lecture VIII.-This lecture contains the conclusions to be drawn from the pathological cases related in the preceding lectures, as regards the diagnosis of alterations in the various parts in the spinal cord. Leaving aside the movements of the heart and lungs, the state of the sphincters, and of animal heat and nutrition, the groups of symptoms existing in disease of the spinal cord, according to the situation and extent of that disease, are thus summed up :"1st. Deep alteration of the posterior columns in all their length.-Increased sensibility in the trunk and limbs for impressions of touch, for those due to pricking, pinching, and galvanic excitations, and for changes of temperature (cold and heat). Loss, or a very great diminution, of reflex movements. All kinds of voluntary movements possible, and more or less easily executed when the patient is in bed. Walking and standing very difficult.*

* On account of the loss of reflex action, and of the morbid sensibility, and also on account of the alteration in the guiding sensations coming from muscles-an alteration which is due to two causes, one of which is the loss of action of some of these conductors altered in the posterior columns through which they pass before reaching the gray matter, while the other is the morbid increase of sensibility of those conductors which go directly into the gray matter.

"2d. Deep alteration of the posterior columns in the extent of the cervico-brachial swelling. Increased sensibility in the four limbs, and in the trunk, for all kinds of impressions. Diminution of reflex actions in the upper limbs, and increased reflex actions in the lower limbs. Some difficulty in the direction of the movements of the upper limbs, without the help of the sight. Standing and walk. ing possible without any great difficulty.

3d. Deep alteration of the posterior columns in the extent of the dorso-lumbar swelling.-Increased sensibility in the lower limbs, and normal sensibility in the upper ones. Diminution or loss of reflex actions in the lower limbs. Movements of lower limbs possible, and even easy, when the patient is in bed; but walking and standing very difficult.

"4th. Deep alteration of a very limited part of the posterior columns.-Increased sensibility, and increased reflex action, in all parts receiving their nerves from the spinal cord below the alteration. Voluntary movements possible and easy everywhere. The place of the alteration may be detected by diminution of reflex actions in the zone round the body receiving nerves from the level of the part altered in the posterior columns.

"5th. Alteration of the posterior columns and posterior roots of the spinal nerves. -Instead of hyperæsthesia, as in the preceding cases, diminution or loss of all kinds of sensibility, in places receiving the spinal nerves, continuing the roots which are altered. Voluntary movements still possible in bed, and while the patient looks at his limbs, but walking and standing almost impossible. Reflex actions completely lost in all the anaesthetic parts. If the alterations are in the upper parts of the spinal cord, the other parts being healthy, then voluntary movements in the lower limbs, and even walking or standing, are possible, and may be easy, and these limbs have an increased sensibility and increased reflex actions.

"6th. Alteration of the posterior columns and of the gray matter in all their length. There is no difference between this case and the preceding, except that here there is a real paralysis of voluntary movements, which is complete if the alteration extends to the anterior gray cornua. Greater frequency of formication and other sensations referred to the periphery.

"7th. Alteration of the posterior columns and gray matter in any limited part of the spinal cord.-Very nearly complete loss of sensibility. Degrees of paralysis of voluntary movements varying with the place occupied by the alteration in the length of the spinal cord. Reflex actions increased in parts receiving their nerves from the parts of the cord below the seat of the alteration.

"8th. Alteration limited to the gray matter.-The same symptoms as in the preceding cases, except that at first there is a greater degree of anesthesia than of paralysis, if the alteration begins in the very centre of the cord. Formication and other sensations referred to the periphery, in cases of inflammation.

"9th. Alteration of the anterior columns in the upper part of the cervical region. -No paralysis, no anesthesia, very slight hyperesthesia, various sensations, particularly pain, referred to several parts of the body.

"10th. Alteration of the lateral columns in the upper part of the cervical region. -Paralysis of voluntary movements in the four limbs and the trunk. Increased sensibility and increased reflex actions in the paralyzed parts.

"11th. Alteration of the anterior columns in any part of their length, except the neighborhood of the medulla oblongata.-More or less complete paralysis of voluntary movements in all the parts receiving their nerves from or below the parts of the cord where the alteration exists. Slight hyperesthesia. Reflex actions very much diminished in the parts which receive their nerves from the altered portion of the cord, and increased below these parts.

"12th. Alteration of the lateral columns in any part of their length, except the neighborhood of the medulla oblongata.-Incomplete paralysis of movements. Hyperæsthesia. Diminution of reflex actions less than in the preceding case.

13th. Alteration of the anterior half of the spinal cord, including the anterior columns, a good part of the gray matter, and a part of the lateral columns.— Voluntary movements completely paralyzed. Sensibility very much diminished. For reflex actions, as in 11th.