affected spot. Usually the paralysed muscles are relaxed. Sometimes they are the seat of early clonic contractions, or these may come on a few days after the onset. When the hemorrhage is in the cervical region all the limbs are powerless; one arm is often affected before the other. The state of reflex action varies according to the seat of the disease; if it is at first abolished it quickly returns in the legs (unless the hæmorrhage is in the lumbar enlargement), and it soon becomes excessive unless destroyed by secondary myelitis-a not unfrequent consequence. In one case there was a remarkable initial increase of myotatic irritability a few hours after the onset, probably irritative, and quickly giving place to loss.* Vaso-motor and trophic changes in the skin are common and often intense; there is often vascular dilatation; bedsores readily form, and cystitis may result. Frequently the secretion of sweat is increased for a time. The temperature is normal at the onset, but it generally rises in the course of a few days from secondary inflammation in the cord.

The palsy developed at the onset usually continues for a week or ten days, although the pain may lessen. The symptoms do not always increase during the stage of inflammation, perhaps because this only involves the structures which are already impaired by pressure; but if the patient has been brought near to death by the primary hæmorrhage, the secondary inflammation may end life. Occasionally, moreover, symptoms of an ascending or descending myelitis may come on, and the former may cause death by its interference with the muscles of respiration. This extension is greatest probably in cases of myelitic hæmorrhage, in which the extravasation is merely an incident in the course of a commencing inflammation, but it seems also to occur in cases of primary hemorrhage. The slow extension upwards of the symptoms, during the first week, may be very distinct; and the occurrence of descending inflammation may be shown by the loss of reflex action and by the failure of electric irritability in the muscles, sometimes only in those supplied from the upper part of the lumbar enlargement. The symptoms pass into a chronic stage, improvement being usually slow. Some lasting loss of power remains in most cases, and there is often some permanent muscular wasting on account of the frequency with which the hæmorrhage is in the cervical or lumbar grey matter. Occasionally there is rapid recovery up to a certain point; a hæmorrhage of small size may abolish conduction in the white columns by the suddenness with which it compresses them, and the effects of the pressure may quickly pass away, while those remain that are due to the destruction of the grey matter.

DIAGNOSIS. The diagnosis rests on the actually sudden onset of the symptoms, and on the occurrence of pain, in a limited region, as part of these. The former is evidence of a vascular lesion (rupture or closure), and the latter shows an acute irritation of the nerveelements, such as may be produced by their laceration, but not by

mere deprivation of blood.

It must be remembered, however, that we cannot assume that symptoms which come on during the night's sleep are of sudden onset. Neglect of this consideration sometimes causes a mistake in diagnosis. The mode of onset is a sufficient distinction from all other organic diseases, except hæmorrhagic myelitis and meningeal hæmorrhage. The former (really a variety of hæmorrhage) is distinguished by the existence of slight symptoms before the sudden attack. We are not justified in regarding as primary hæmorrhage any case in which premonitory symptoms existed for more than a few minutes, unless such symptoms were so pronounced and sudden in onset that they might have been due to a definite extravasation, afterwards increasing. Initial fever (within the first six hours) always makes myelitis probable, provided there is no other cause for it. The distinction from meningeal hæmorrhage has been mentioned in the account of the symptoms, and in the description of that disease.

PROGNOSIS. In all cases in which the symptoms are considerable in degree or wide in range, the danger to life is great, and remains great until they begin to subside. The prognosis is better when the disease is in the dorsal region than when it is in the enlargements, for the same causes as influence the prognosis in myelitis. It is better when sensation returns in the course of a few days, but if the enlargements are affected other sources of danger remain considerable. Early trophic changes also render the prognosis worse, for they show an intensity of degree that may involve grave danger. After the onset is over, the forecast must be guided by the general principles that determine the prognosis in acute myelitis.

TREATMENT. The treatment of hæmorrhage into the substance of the cord is the same as that of hæmorrhage into the membranes (p. 295). The measures requisite are few, simple, and all-important. Absolute rest and the prone position are to be secured before anything else is thought of. Ice should be applied to the spine over the seat of the hæmorrhage. The bowels should be opened freely, and full doses of ergot or ergotin may be given: 3ss of the liquid extract or five grains of ergotin may be given by the mouth, or three grains of ergotin may be injected under the skin, and the dose may be repeated two or three times, at intervals of two hours. A few large doses are probably more effectual than smaller doses continued for a longer time, since the hæmorrhage probably does not go on for long. The aftertreatment must be that for myelitis. The disease is one of those in which most of t'e good that can be done by treatment-and in few diseases is the opportunity more urgent-rests with those in whose hands the patient is immediately after the onset.

DEGENERATIONS OF THE SPINAL CORD.

A large and important class of diseases of the spinal cord consists of those in which there is a slow degeneration of the nerve-elements, with an overgrowth of connective tissue, and in which structures are affected that have a common function, while others that have a different function escape even when they are adjacent to the elements that are diseased. Affecting thus functional "systems," they are termed "system diseases." This term has been used in several senses, more or less special (even based on the developmental relations of the structures), and hence the question whether a given malady is a "system disease" or not, is one to which various answers have been given. The term is here used in its widest and simplest sense, as meaning an affection of the structures that have a function either the same, or so far allied that they work together as parts of one system, distinguishable as such from other sets of structures. A "system disease" may involve all the structures of the system, or only some or one of them; its chief distinction is from a random disease that involves structures irrespective of function-merely, for instance, because they are contiguous, or supplied by the same artery.

In "system diseases," the primary change is, as a rule, in the nerve-elements, and the overgrowth of interstitial tissue is secondary. The process is analogous to that which occurs in the secondary degeneration of nerve-fibres, in which the first change is certainly in the nerve-elements, the destruction of which is followed by an overgrowth of nuclei and supporting tissue, amounting ultimately to a "sclerosis," as it is termed. The process is by some regarded as a chronic parenchymatous inflammation, an inflammation beginning in the proper functional elements of the organ, but it seems undesirable thus to widen and loosen our conception of inflammation; so far as the process is concerned the question is one of name rather than of

nature.

Another question of much greater interest is the relation of the two elements in the process, the wasting and the growth, the atrophy of the nerve-tissue, the hypertrophy of the connective tissue. The failure of nutrition in the one causes an increased energy of nutrition in the other. We have seen this relation in the nerve-fibres. The degene ration of a fibre is attended by an active growth of its nuclei and protoplasm. The nutrition of the two elements, the neural and the adventitial, is evidently connected in the closest manner, but in inverse course. It is important to recognise the fact that the process of growth of the connective-tissue elements is an active manifestation of nutritional energy, which, when once excited, may be to some extent independent of its cause. It may, when very active, pass beyond its proportional limits, and be greater than corresponds to the nerve

atrophy that causes it; invading adjacent structures as if an independent process. It may, when very rapid, have some of the characters of an interstitial inflammation, and even an acute inflammation. Such excess is quite unusual; as a rule the secondary process is subordinate and proportioned to the primary change.

These degenerative diseases fall into certain types so far as the spinal cord is concerned, but they are subject to some variety of combination even there, and to great diversity of association with degenerative changes elsewhere. The affection of the cord is of either the sensory or the motor elements, or both. The type of the former is tabes; of the latter, either spastic paraplegia or muscular atrophy, according as the lower segment at the motor path is affected or free. Other combinations of affection will be better understood when the diseases are described.

The degenerative diseases are not numerous, but they are of great importance. They are degeneration of the anterior cornua and anterior root-fibres, causing muscular atrophy; degeneration of the posterior columns and posterior root-fibres, causing locomotor ataxy; and degeneration of the pyramidal tracts, causing spastic paraplegia, a disease the exact pathological position of which is not quite certain. These degenerations may be variously combined, and some combinations need separate description.

LOCOMOTOR ATAXY; TABES DORSALIS.

The malady thus named is the most common chronic disease of the spinal cord. It consists in a degeneration in the posterior columns of the spinal cord, or the peripheral sensory nerves, or both, and is manifested, when considerable, by inco-ordination of movement, peculiar pains, defective sensibility, and loss of the myotatic irritability (musclereflex action), of which the knee-jerk is the most convenient manifestation. When slight in degree, the symptoms may be limited to the pains and the loss of the knee-jerk. The name "locomotor ataxy" was given to the disease by Duchenne; "tabes dorsalis," or "wasting of the back," is a term applied by Hippocrates to certain symptoms supposed to be due to venereal excess, and long ago limited in Germany to symptoms believed to depend on atrophy of the spinal cord. It then included all chronic paraplegias, but was further restricted to this disease by Romberg. It has lately obtained wider use on account of the discovery that inco-ordination may be absent when the disease is slight in degree.

The symptoms vary much in different cases. Besides the varieties

thus produced, there are two allied affections that ought not to be classed with it. One is the so-called “hereditary ataxy." The other is that in which both weakness and inco-ordination co-exist from the first; "atarie paraplegia" it may be called. Each differs from other varieties with suficient constancy to merit separate consideration. These varieties are not included in the following account.

HISTORY.-The inco-ordination of movement and other symptoms of the disease were frequently noted, during the first third of this century, in cases of disease of the spinal cord, but such cases were not distinguished from those with actual loss of power. The inco-ordination was found to be associated with disease of the posterior columns by Stanley. The first really exact account of the disease was published in 1847 by Todd, who distinguished the cases with inco-ordination and without weakness, from simple paraplegia, and, apparently not aware of Stanley's observation, he inferred (from the character of the symptoms and his theory that the posterior columns contain. fibres connecting segments of the cord at different levels) that the posterior columns would be found diseased; and he verified this inference by finding in two cases disease of these columns. The credit of the discovery of the disease belongs, if to anyone, unquestionably to Todd, and few diseases can with greater truth be said to have been "discovered." Four years later (in 1851) Romberg described the disease and the lesion in the posterior columns, but he failed to exclude loss of power from the symptoms. Russell Reynolds, in 1855, gave an accurate description of the symptoms, and, in attributing the ataxy to muscular anesthesia, was the first to give what we must now regard as the true explanation of the chief symptom. A series of cases was described by Gull in 1856 and 1857. Türck first observed with the microscope the wasting of the fibres in the posterior columns. Duchenne in 1858-9 published an independent and very able analysis of the symptoms of the disease, and gave it the name "locomotor ataxy." He obtained for it (with the help of Trousseau's "Lectures") the recognition that previous descriptions had failed to secure, and achieved such a degree of success that the malady is called in France, Duchenne's disease. If any name is attached to it, that of Todd alone can be right.

CAUSES.-The disease is much more frequent, in this country at least, in urban than rural populations. Inherited influence is to be traced only in a small proportion of the cases, perhaps in not more than 10 per cent. It is usually a general neurotic heredity, manifested by such diseases as insanity, epilepsy, and other degenerative diseases 'Med. Gazette,' Feb., 1840, and Med.-Chir. Trans.,' vol. xxiii. +Cyclopædia of Anatomy and Physiology,' vol. iii, p. 721.

Reynolds, Diagnosis of Diseases of the Brain, &c., 1855, "Anesthesia Muscu laris." Certain words are worth quoting:-"It appears most probable that the centripetal tract of fibres is affected, and that the locality of lesion is very variable" (p. 165).