wards, probably in the short fibres that connect the anterior cornu at different levels. In other cases, in which the anterior ganglioncells were normal, the sclerosis has not been limited to the pyramidal tracts; the anterior columns have been also sclerosed in the lumbar region of the cord. The direct cerebellar tract and posterior vesicular columns have been also found degenerated with the pyramidal tract, and an annular sclerosis of the periphery of the antero-lateral column has been found in several cases. More frequent still is a combination with degeneration of the posterior columns, described more fully in the next section. In most of these combined cases the degeneration has lessened in the upper part of the cord. In one case, at least, the white columns of the cord have been found healthy. The probable significance of this fact has been already stated. It should be remarked, however, that there seems sometimes to be a tendency for the morbid process to extend beyond the pyramidal tracts in a manner that suggests a greater tendency for the secondary connective-tissue changes to take on an independent invasive activity than in other system diseases. (See also Ataxic Paraplegia.) Another point that deserves mention is the occasional occurrence of lateral sclerosis in association with insular sclerosis. In some cases of this character the degeneration of the pyramidal tracts is purely secondary, the result of the damage to the pyramidal fibres by an islet of sclerosis situated in some part of their course. But it does not appear that this explanation can be given of all cases. In some instances the sclerosis of the pyramidal tract appears to be independent and coincident. A similar association of insular and posterior sclerosis has also been observed; and such combinations receive additional emphasis from the fact that insular sclerosis may be accompanied by a primary atrophy of the optic nerve, precisely such as occurs in tabes. These facts make it probable that lateral sclerosis, although a system disease, is often one of less strict features than tabes, having some tendency towards chronic myelitis. We shall see that this is true also of ataxic paraplegia.

The probable mechanism of the symptoms that give the dominant characters to the malady have been considered in the general account of the symptoms of disease of the spinal cord. The most important fact is that the degeneration, whatever its upward extent, always involves the lowest part of the pyramidal segment, because it seems to begin in this and ascend the fibres. Hence the intra-cornual termination must always be involved. This, it is assumed, is the structure that controls the muscle-reflex centre, and the consequent loss of control

As in a case recorded as one of spastic paraplegia by Hopkins (Brain,' Oct., 1883), but this was an example of combined lateral and posterior sclerosis (ataxic paraplegia). An illustration of the changes in this case is given in the next section.

+ Direct cerebellar and pyramidal tracts in a case by Minkowski, in which the disease rapidly succeeded syphilis; annular sclerosis by Westphal (see "Ataxic Paraplegia").

VOL. I.

29

explains the excess of myotatic irritability and the progressive spasm, progressive by what may be termed a functional hypertrophy resulting from continuous over-action. When there is the rare consecutive wasting of muscles, we must conceive that the degeneration involves also the ganglion-cells and lower segment of the motor path; when there is coincident wasting of other muscles than those that are the seat of spasm, it would seem that some elements of this lower segment are the seat of a primary degeneration. The slighter muscular wasting without, or with only trifling, change in electrical irritability, is the expression of a slighter alteration in the nutrition of the cells and fibres, without actual destructive degeneration.

DIAGNOSIS.-The diagnosis rests on the combination of weakness, excess of myotatic irritability, and spasm,-on the gradual onset of these symptoms,-and also on the absence of indications of a focal lesion. An acute onset, occupying a few days or weeks, is primá facie evidence of a lesion that takes the case out of the category of degenerative disease. In most acute cases there is other evidence of a focal lesion, extending, at some level, beyond the limits of the motor path. Such indications are initial impairment of sensation, or a girdle-pain. The latter indicates irritation of the posterior root-fibres at a certain level, and proves that at that level the disease extends beyond the limits of the pyramidal tracts. Spastic paraplegia is common after such lesions, but is secondary and not primary.

Although marked sensory symptoms, in a case that presents the symptoms and course of primary lateral sclerosis, are thus evidence that the sclerosis extends beyond the motor tracts, and that the case is not one of pure lateral sclerosis, it is doubtful what significance is to be attached to very slight sensory symptoms, such as slight subjective sensations of dull pain, formication, &c., when they exist alone. It is possible that they are due to functional disturbance in the sensory nerve-elements, and do not imply structural disease outside the motor area. They are not followed by any more pronounced sensory symptoms.

The absence of objective unsteadiness is the chief distinction from ataxic paraplegia (q. v.). When this is slight, it may be difficult to say in which class a case should be placed. There are no doubt intermediate cases in which there is a very slight degree of the additional lesion that exists in ataxic paraplegia, but the distinct objective character of the ataxy is the best criterion. Considerable muscular wasting in any part is commonly regarded as bringing the case into another category, that of "amyotrophic lateral sclerosis;" but some cases of the kind, in which the wasting is confined to a few muscles, resemble more closely the cases we are now considering than they do those with wide-spread and extreme muscular atrophy. These cases are further considered in the account of progressive muscular atrophy.

Primary spastic paralysis is not uncommon in those who are at the age and of the sex at which hysteria prevails, and there is no form of

cord disease that is so often mistaken for hysterical paraplegia. The mistake is facilitated by the perfect muscular nutrition. But the mistake ought not to occur, as the peculiar extensor character of the spasm, lessening with flexion, is distinctive; nothing resembling it ever occurs in hysterical paraplegia. When the spasm is trifling or absent, as in slight and early cases, the diagnostic difficulty is much greater, and is increased by the fact that slight excess of myotatic irritability occurs in some cases of so-called hysterical paralysis. But this scarcely ever reaches the degree necessary to give rise to a true foot-clonus or a rectus-clonus. There may be a slight clonus produced through a voluntary depression of the foot of the patient in response to the passive flexion of the ankle, and readily recognised; or a true clonus may be obtainable during hysterical contracture, but apart from such contracture a true foot-clonus or a rectus-clonus deserves the greatest weight, as all but conclusive evidence of organic disease. I have known many mistakes in diagnosis, in which lateral sclerosis was mistaken for hysterical paraplegia owing to disregard of the evidence afforded by this symptom, but I have never known the opposite error from undue regard to this symptom. Moreover, an excess of myotatic irritability in so-called hysterical paralysis must depend on more than functional disease. There must be changes in nutrition, and consequent persistent defective control of the musclereflex centres. On the hypothesis that I have advanced, this control is exerted by the termination of the pyramidal fibres, i. e. of the upper motor segment, by the structures degeneration of which probably causes spastic paraplegia. A case is actually on record (the case of lateral sclerosis described by Charcot in 1865) in which an initial hysterical paraplegia, cured suddenly and relapsing on emotion, passed ultimately into lateral sclerosis.

When the arm and leg suffer on one side only, the disease may be mistaken for cerebral hemiplegia. There is not, however, any affection of the face, which, although theoretically conceivable, is, as a matter of fact, always absent. The limbs on the other side are never quite normal, but present slight symptoms-weakness and an excess of myotatic irritability-similar to those on the affected side, which indicate the nature of the malady.

The diagnosis of the congenital infantile form is only difficult when the observer is unaware of the occurrence of these cases. A slight degree of inco-ordination in the hands will usually be found if they are carefully watched while the patient takes hold of some object. The wide separation and irregular movement of the fingers is very characteristic. Chronic primary cord diseases are almost unknown in young children. Caries of the spine is, in them, the chief cause of paraplegia; and the definite onset of the paralysis, in a previously healthy child, is an absolute distinction from the cases of birth-palsy. Other diagnostic indications are described in vol. ii (Infantile Meningeal Hæmorrhage). A definite onset also distinguishes glioma of the

pons, which may likewise cause spastic paralysis of arms and legs.

PROGNOSIS.-In primary lateral sclerosis there is some prospect of arrest, and even of improvement, if the disease has not reached an advanced stage. Actual recovery is rare, but does sometimes occur in early cases. When the spastic state is well developed and has lasted for some time, it is very rare for more than arrest to be obtained. This is perhaps due rather to the tendency of the disease than to its degree, since a similar condition that is secondary to a focal lesion often recovers perfectly; and many facts show that it is not likely that there is anything in the nature of the lesion to preclude the restoration of a normal condition, until dense connective tissue has replaced the nerve-elements. In the cases that improve most, it is possible that the disease is limited to the terminal structures. We have not, at present, any guide to the prognosis in an individual case, besides its duration and degree, except its observed tendency, especially under treatment. The prognosis of the infantile form is considered in vol. ii. TREATMENT. So far as drugs are concerned, the treatment is, to a large extent, the same as that of posterior sclerosis, already described. The drugs most useful are the same, but, unfortunately, their influence is less frequently appreciable. Nux vomica and strychnine have, however, to be given with caution, and in very minute doses, as they have a tendency to increase the spasm. In severe cases this is a most distressing symptom, and often not amenable to any influence. Bromide sometimes lessens it slightly, but even large doses of bromide have but a trifling effect. Indian hemp, belladonna, and calabar bean may be tried, but seldom have a distinct influence. One of them may be combined with arsenic, or whatever metallic agent is employed. Absolute rest is sometimes of service, and occasionally seems to produce improvement, which all treatment failed to effect while the patient was walking about. The avoidance of fatiguing exertion is a very important element in treatment, and often seems to permit medicines to do good, which before were counteracted. Rubbing is also beneficial in some cases. Its influence on the spasm is often very distinct during the process, and a long course of rubbing has produced a permanent improvement in the spastic condition. Upward rubbing seems to have more influence than kneading the muscles. If there is contracture of the calf-muscles, the foot should be pressed up while these muscles are rubbed. When there are facilities for it, the rubbing may advantageously be combined with sweating in the Turkish bath. In one case, of moderate degree, almost all the symptoms passed away after a long course of Turkish baths, arsenic being also given. The patient, who could at first walk scarcely half a mile, became able to walk several miles without fatigue, and the improvement was permanent. Electricity is useless in the pure disease. Faradism and all painful applications are harmful, stimulating further the already excessive excitability of the reflex centres. The

constant current to the muscles, or from the spine to the muscles or to the feet in water, has no distinct influence in either lessening the spasm or improving the strength.

In the infantile form, drugs are useless. Rubbing is desirable, and can be efficiently performed by the nurse or mother. Carefully planned gymnastic exercises are also useful. The tendo Achillis is sometimes divided for the contracture of the calf-muscles, but the operation is useless and ought never to be performed. Supports help the child to walk somewhat sooner than it would without their aid, and so hasten improvement, but they should only be employed when there is sufficient power and control to make them useful by enabling the will to effect ordered movements.

ATAXIC PARAPLEGIA

(COMBINED LATERAL AND POSTERIOR SCLEROSIS).

The term ataxic paraplegia seems the most accurate clinical designation for a disease of the spinal cord which presents a combination of the symptoms of paraplegia and ataxy, and consists in combined disease of the posterior and lateral columns. Although its clinical features present some varieties, and may approach those of each of its constituent forms of disease, yet in the majority of cases the symptoms are uniform, and sufficiently characteristic to justify the distinction of the disease and its separate description. A few pathological observations have been published. The following account is based on these and on a series of cases that have come under my own observation, and of which the clinical characters were well marked.*

CAUSES.-Neurotic heredity is to be traced only in a small proportion of the cases-about one tenth. A history of syphilis is as rare as it is frequent in pure tabes. Males suffer much more frequently than females. The disease usually commences between thirty and forty, but I have known it to begin as early as nineteen and as late as fifty-two, while commencement at fifteent and at sixty-one‡ is on record. Exposure to cold is to be traced occasionally as an exciting cause. In one young lady the symptoms commenced after a season

See Prevost, Arch. de Physiologie,' t. iv; Pierret, ib.; Babesieu, Virchow's Archiv,' Bd. lxxvi; Kahler and Pick, Arch. f. Psychiatrie,' Bd. viii; Westphal, ib., Bd. viii and x; Dana, New York Med. Record,' July 2, 1887; and Clarke, Brain,' 1890. The condition was described by Déjérine in 1884 under the name of "ataxoparaplegic tabes;" see Ladame, Brain,' 1890, part lii, p. 530. I have not seen Déjérine's description, and did not know of it when the above chapter was written. Oppenheim, Neur. Cent.,' 1888, p. 647. Such early cases are generally isolated forms of "Hereditary Ataxy." Suckling, Lancet,' 1886.