portance. The state of the muscular fibres has been ascertained from excised fragments-a method which, however, involves the fallacy, already mentioned (p. 534, note), of possibly stimulating the fibres to contraction. At the same time, the evidence of hypertrophy appears conclusive. Where the minimum width was the same as in health, the maximum diameter was double the normal (Erb). In other cases the maximum or even average diameter in fragments excised under chloroform was double that observed after death in unaffected persons; and that the size was pathological was rendered probable by the aspect of the fibres, which presented indistinct striation, fewer " sarcous elements," irregular, non-parallel edges, and sometimes vacuolation. An increase of the nuclei and of the interstitial connective tissue has been found.*

The manifestation of the disease is in a disorder of the functions of the muscles, and most writers on the subject have followed Leyden in regarding the malady as essentially muscular in nature, as consisting in an altered functional condition of the muscular tissue. This opinion is strongly supported by the frequent alteration in electrical excitability (which can hardly be otherwise interpreted than as an indication of a change in the mode of action of the contractile muscular protoplasm), by the structural changes, and also by the interesting experiments of Ringer and Sainsbury, who found that certain salts, such as sodium phosphate, are capable of causing in the frog tonic spasm bearing considerable resemblance to that of Thomsen's disease, and that such spasm persists not only after the nerve has been divided, but after the intra-muscular nerve-endings have been paralysed by curara. This does not prove that Thomsen's disease is muscular in origin; it is a proof that a similar state may be due to the muscular tissue, but no proof that this is the sole element in Thomsen's disease. We must remember that the malady has apparently resulted, in rare cases, from influences acting on the nervous system in adult life, and also that, in the congenital cases, the spasm only develops, as a rule, after some years of voluntary action. It may thus be an acquired disease, and the case related at the end of this chapter shows that similar spasm may be due to a primary affection of the cord. The spasm is a transient consequence of rest. But "rest" is not inactivity, either in the nerve-cells or muscles. Muscular "tone" and adaptation to posture mean an unceasing flow of nerve-force from the cells, an overflow perhaps, due to the perpetual elaboration of energy which keeps the cells ready for instant response to the voluntary stimulus. The tonic activity then ceases, or at least does not interfere with the different action excited by the will. But the phenomena of Thomsen's disease suggest that the cells respond abnormally to the voluntary stimulus, that this causes at first an increased tonic activity, slowly ceasing as their energy is lessened by

Erb, Seifert, and also Nearonow, 'St. Petersburg psych. Gesellsch.,' 1889; see 'Neur. Cent.,' 1889, p. 239. Hale White found no increase in the nuclei.

action. Wide as is the difference between the muscular and nervous tissues, we must remember that they have some conditions in common. The dependence of the nutrition of the muscles on that of the motor nerve-fibres and cells is a very remarkable fact, and so also is the influence of the functional activity of the cells and fibres in causing a similar condition in the muscular tissue. To say that the two structures are connected is hardly an explanation of the fact. Whatever is the nature of the relation between them, it is at least conceivable that an abnormal functional state, congenital in origin, may be common to the two, and that the peculiar over-action in the muscles may be accompanied by a similar over-action in the ganglion-cells of the spinal cord, and even in the pyramidal cells of the cerebral cortex. It is even conceivable that the condition of the nerve-cells may be the primary change, and that of the muscles may be secondary, although, when produced, it is in some degree independent, and may be excited independently by local stimulation. Such a theory enables us to understand the two facts above mentioned -the influence of emotion and the acquisition of the disease, each of which seems to be inconsistent with a purely muscular pathology.

TREATMENT.-No treatment, properly so called, appears to exert any influence on the disease. The congenital malady persists through life; in the cases in which a similar condition has apparently been acquired, it has also been persistent. The only influence that has appeared to Thomsen to ameliorate the condition is a life of active muscular exertion. But it is possible that the influence of therapeutics is not yet exhausted.

Congenital Paramyotone.-Under this name Eulenberg has described a strange family affection, allied to Thomsen's disease in its general character, although differing very much in its special features, and equally obscure in nature. The malady was widely spread in the affected family, and could be traced through six generations, but appears now to be dying out. Its congenital character was shown not only by its multiplicity, but also by the fact that in some individuals it was manifested immediately after birth. The symptom was tonic spasm, lasting from a quarter of an hour to several hours, excited chiefly by cold, although often by merely slight cold. The rigidity was followed for a time by weakness. The facial muscles were very prone to become thus rigid, especially the orbiculares palpebrarum and oris; and while the contraction lasted the patient was often unable to speak or to open the eyes. The rigidity was slighter in the legs than in the arms, but the subsequent weakness was equally marked. Warmth removed the spasm. There was no persistent loss of power, and no increase of mechanical irritability. The electrical excitability of the nerves was normal; that of the muscles was lowered to each current,

'Neurologisches Centralblatt,' 1886, p. 265.

and there was an abnormal tendency to tetanic contraction during the passage of the current. Eulenberg speculates that the symptoms. may be due to reflex vaso-motor spasm in the muscles, because the diminution of the blood-supply to muscles renders them weak; but it is clearly equally possible that the two certain phenomena, the sensory impression and the muscular contraction, may be directly connected.

Ataxic paramyotone seems the best provisional designation for an acquired condition of which one case has come under my notice. Persistent tonic spasm, like the transient spasm of Thomsen's disease, was associated with distinct ataxy, and also with weakness and some anesthesia. The symptoms commenced gradually in the legs, in a healthy man, aged 40, without neurotic heredity; it invaded the arms six months later, and increased more rapidly in the arms than in the legs. At 41 his state was this. A well-built man, with well-developed muscles, unduly firm in all parts except the neck and head. The firmness was due to tonic spasm, which never ceased. It was present on waking in the morning, and through the day interfered with all movements, making them slow and stiff. He rose from a seat slowly and with difficulty; when standing there was slight unsteadiness, increased by closing the eyes, and a slight impulse or stumble in walking would cause a fall, chiefly because the spasm prevented the needed quickness of movement to save him. Prolonged exertion had no influence on the tonic spasm, which opposed passive, as much as active, movement. Power in arms and legs was lessened, but not considerably. The grasp 50 and 55 ko. The extensors of the fingers were weaker than the flexors, but could act perfectly although involuntary flexion followed the slow extension. The electrical irritability of the muscles seemed to be normal. Inco-ordination was especially marked in the hands; with eyes shut, buttoning his coat was almost impossible; the attempt was made with thumb and forefinger, the others being flexed, and he could touch his nose only after many wandering failures. On the palms, from the wrist to the tips. of the fingers, sensibility was lost to touch, slightly delayed to pain, little changed to temperature. Slight tactile loss extended to the back of the last phalanges; on the back of the hands it was normal. A similar but slighter loss existed on the soles; he often felt as if walking on a rounded surface. The size and weight of objects placed in the extended hand could not be recognised. No trace of the knee-jerk or other evidence of myotatic irritability could be elicited, but the spasm was enough to explain the failure, and its real condition is uncertain. Mind, special senses, and cranial nerves were unaffected.

Unfortunately, the course of the affection could not be observed. Its symptoms must have been due to disease of the spinal cord, and

they are instructive as showing that muscular spasm, like that of Thomsen's disease, may be thus produced. The time may not have been sufficient for the production of changes in the irritability of the muscles, but we must also remember that differences in the influence on the muscles may be connected with the defective power.

TUMOURS OF THE SPINAL CORD.

Morbid growths within the spinal canal may spring from the membranes, or may grow in the substance of the cord itself. The difference in seat entails some difference in symptoms, but it is nevertheless convenient to consider the two classes together, because they have many symptoms in common, and it is often impossible to carry the diagnosis farther than the existence of an intra-spinal tumour.

ETIOLOGY.-The general causes of these growths correspond, for the most part, to those concerned in their production in other situations, and present few peculiarities that merit special mention. Fatty growth outside the dura mater occurs early in life; malignant tumours develop late. Of tumours within the dural sheath, myxomata are chiefly met with in middle life, tubercular growths occur occasionally in childhood, but generally between fifteen and thirty-five (Herter); lipomata are congenital. Males are a little more prone to suffer than females.+

Of the diathetic conditions which give rise to tumours elsewhere, only two, syphilis and tubercle, are effective in causing growths which commence within the spinal canal. Parasitic tumours occur, due to the same influences which produce them in other situations. A few rare growths appear to be congenital in origin, due to the abnormal development of germinal tissue, while the more common gliomata within the cord arise from embryonal tissue, which has suffered an arrest of its normal development. Of the causes of other forms of tumour we know practically nothing. Injuries, such as a blow on the spine, have been supposed to be occasional causes, and their influence in rare instances has seemed possible, but the evidence is not so strong as it is in the case of tumours in some other situations. In many cases the first symptoms have immediately followed some exposure to cold and wet, and it seems

• Herter, 'Journ. of Mental Dis.,' 1890, has analysed twenty-six cases.

A collection of facts relating to these points, by Mr. Victor Horsley, will be found in the paper written by him and myself on the case of successful removal of a tumour from the spinal cord, 'Med.-Chir. Trans.,' 1889; but the numerical basis is far too meagre to supply more than statistical suggestions. It will be necessary to wait for a considerable time before adequate data are obtained.

probable that this influence may have excited secondary processes in the nerve-elements which were already deranged by the growth, and may thus have frequently excited the first symptoms of the tumour, but it can have had no share in the production of the growth itself. Traumatic hæmorrhages may, however, result in cystic formations, which have been mistaken for new growths.

PATHOLOGICAL ANATOMY.-The growths within the spinal canal may develop outside the dura mater, inside the dura mater, or within the substance of the cord. The extra-dural tumours may spring from the membrane, or from the tissue between the membrane and the bone, or may grow into the canal from the outside, through the intervertebral foramina. Subdural tumours may proceed from the inner surface of this membrane, from the arachnoid, or from the pia mater (Fig. 165). The growths in the cord may spring from the pia mater, or may develop in the substance of the cord. They sometimes proceed from the peculiar tissue which surrounds the central canal.

The forms of extra-dural tumours are lipoma, from an overgrowth of the fat which normally exists between the membranes and the bone; and parasitic tumours, chiefly echinococci ; but all are rare. Growths also occur that spring from the bones or intervertebral tissue-enchondroma, sarcoma, and cancerous tumours, which have been already considered. Far more frequent are collections of inflammatory products from bone disease, but these do not come into the category of morbid growths.

B

A

FIG. 163.-Myolipoma of the spinal cord. A, transverse section of the tumour and of the conus medullaris of the spinal cord, to which the growth was attached, and of which the grey matter is represented by the dotted shading O M. n, sections of nerve-roots, partly enclosed in the tumour; m, bundles of muscular fibres. B, part of the tumour more highly magnified, showing the fatcells, of which it was chiefly composed; p.m. pia mater of the cord, of which l.c. is part of the lateral column. C, part of the tumour, still more magnified, showing striated muscular fibres, fibrous tissue, and fat-cells (see also Fig. 157, p. 517). The tumour had caused no symptoms.

An adeno-sarcoma has also been met with (Hodenpyl, Am. Journ. Med. Sc.,' 1888).