induce this abnormal increase. These remote causes it is the object of diagnosis to discover.

A. The change in question may be idiopathic or primary ; i. e. a morbus per se. This is warrantable from experience, and from general pathologic laws. It may be developed hereditarily, or from conditions operating after birth. Disease must begin somewhere, and there is no ground for saying that it shall not begin in the reflective centre, and in this form.

B. Morbid increase of nutrition-change may be secondary to some other abnormal condition. The latter may be an "eccentric irritation," the intensity of which may be alone sufficient to produce the effect; or which may be such as to require "predisposition" in order to cause convulsion. "Irritation" does not necessarily involve either pain or sensation; it is an "occasion" of vital action.

C. The nutrition of the nervous centres may be involved in a general change. This may be that denominated cachexia; toxæmia, developed from within, or introduced from without; blood-change dependent upon organic disease; or that general change which attends certain leading periods in the development of the body.

These conditions may concur with others, A and B, or they may exist alone.

D. The conditions upon which convulsions depend may be occasioned by structural disease in contiguous portions of the nervous centres.

1. The reflective centre may be involved in actual and definite disease, extending to it from other parts of the cerebrospinal system; or 2. It may be affected through reflex irritation. In the latter case, the causation is, though locally different, similar in kind to that described under the name of eccentric irritation (B).

XII. Upon these differences in remote causation the classification of convulsive diseases depends.

CHAPTER II.

DEFINITION AND NOSOLOGICAL POSITION OF EPILEPSY.

*Few diseases are better characterised by their symptoms than epilepsy; yet, in this instance, there is such a variety in the phenomena as renders it difficult to contrive a definition in a few words, which may comprehend every form of the complaint."-PRICHARD.

EPILEPSY cannot be defined by any anatomical change; for no structural condition has been hitherto found with sufficient frequency to be regarded as an essential element in its production. So universally is this admitted that, although attempts have been made to show the presence of organic lesions as its essential cause, the names by which the disease has been known have borne no relation to such lesions.*

Epilepsy cannot be defined by any one symptom which is peculiar to, and pathognomic of its presence. Those phenomena which reveal its existence, viz. loss of consciousness and involuntary muscular contraction, exist not only in other diseases, but in health. In sleep, as well as in apoplexy, both perception and volition are suspended: in respiration, as it is affected when violent exertion is made, as well as in hysteria, there is involuntary muscular contraction. The mere presence of either spasm or loss of consciousness does not, therefore, constitute epilepsy.

One of the most recent authors who may be cited in confirmation of this position is Dr. Hoffman, of Frankfort, whose examination of the bodies of fifteen epileptics is thus summed up by Köhler (Schmidt's "Jahrbücher," 1859, Bd. 104, p. 133): "Bei den Epileptikern aber fanden sich durchschnittlich keine hervorragenden und specifischen Sektionserscheinungen, ausser etwa lokale Blutüberfullungen, und Vf. hält die Epilepsie für noch viel immaterieller als die Seelenstörungen."

The combination of symptoms, as a mere combination existing at a particular time, does not enable us to define the disease. Loss of consciousness and involuntary spasm occur during sleep; in cases of ventricular hæmorrhage; of hysteria; of acute red softening, and the like.

The particular form which such combinations may assume cannot be employed as a definition of epilepsy; for, on the one hand, the name is extended to various forms of convulsion,-"le petit mal," as well as "le haut mal," of the French authors; and, on the other, the convulsions of infancy, of parturition, of narcotic poisoning, and of urinæmia, are often precisely similar to those of epilepsy.

But, although there is no one symptom or combination of symptoms, the presence of which indicates positively the existence of epilepsy, there is a symptom, in the absence of which it would be impossible to assert that epilepsy was present. This symptom is loss of consciousness; and it is the characteristic phenomenon of the disease.

As it has already been shown, however, that mere loss of consciousness is not, per se, indicative of epilepsy, the distinctive character of the disease must be sought in the conditions of that symptom, and upon those conditions the disease may be defined.

Dr. Todd states, that "the pathognomonic symptom of the disease is a sudden and complete loss of consciousness;"* but this is true only when we add, occurring as a paroxysmal or occasional event. Sudden and complete loss of consciousness may be observed in cerebral hemorrhage, or cerebral congestion; but the occasional repetition of the event, and its temporary duration, are the conditions which render it distinctive of epilepsy.

It has been said, even by those who regard loss of consciousness as the essential phenomenon of epilepsy, that in defining the disease we must combine, with that symptom, involuntary muscular contraction. Thus Portal makes the following statement:-"La convulsion tonique ou clonique d'un seul muscle suffit pour caractériser l'épilepsie, s'il y a perte de connaissance;"† and Maissonneuve thus defines the disease:-"La coincidence au moins imminente de la perte de connaissance, et de sentiment

• Medical Times and Gazette, August 5, 1854, p. 129.

+ Observations sur la Nature et le Traitement de l'Épilepsie, p. 140.

avec les convulsions."* But to such statements it must be replied, that cases occur not infrequently in which no such convulsion or even transient and local spasm can be positively observed, and yet the whole character of such cases and their ultimate development is such as to leave no doubt of their epileptic character. (See Case IX.)

While, however, excluding from the definition of epilepsy a symptom which is not shown to be universally present, it should be stated, that there are grounds for believing that in epilepsy loss of consciousness is invariably associated with, and dependent upon contraction, the result of a motor impulse; but that this impulse may be confined to the contractile fibres of the cerebral vessels. The element of spasm, therefore, is not denied, but affirmed to be one that is essential to the existence of epilepsy; but it is asserted that this element does not necessarily occur in muscles which are exposed to observation.

Epilepsy may then be defined to be a chronic disease characterised by the occasional and temporary existence of loss of consciousness, with or without evident muscular contraction.

Epilepsy should be regarded as an idiopathic disease, i. e. as a morbus per se, distinct from eccentric convulsions, from toxæmic spasms, from the convulsions attendant upon organic lesion of the cerebro-spinal centre, and, in fact, from every other known and appreciable malady.

The special organic condition upon which it depends may be induced in various ways, but it may occur primarily; and, in the vast majority of cases of epilepsy proper in the human subject, there is no evidence to show that the disease is other than idiopathic and primary.‡

In 1855 I made the remark that, "if we can succeed in distributing all the cases hitherto known as epilepsy among the several classes of better defined diseases, we ought to reject the term epilepsy from our nosology: but if we cannot accomplish this distribution, and are compelled to recognise the existence of many, or even of a few, cases distinct from any more general condition of systemic or local disease, then we must employ the * Recherches et Observations sur l'Épilepsie, p. 36.

+ Vide Chap. V., Pathology.

For the sense in which these terms are used, and the reasons why they are applied to epilepsy, the reader is referred to Chapters I. and V.

term epilepsy in a restricted sense, implying only those cases which, in the present state of medical science, are irreducible."* But this principle of nomenclature-which appears little more than a truism, self-evident, and requiring no argument for its support is not that which has been acted upon; and at the present time we constantly hear of renal epilepsy, uterine, gastric, and other epilepsies; epilepsy from tumour of the brain, and other organic diseases; and find these confounded together with the simple or idiopathic affection.

The principle which is now re-asserted is this, that inasmuch as there are numerous cases of epilepsy in which neither organic lesion, blood disease, nor definite eccentric irritation can be shown to exist, epilepsy is idiopathic in these cases; that such idiopathic disturbance is all that exists in them, and that it fills up to the full, in numerous instances, the idea of epilepsy; and that, therefore, when in other cases structural lesions, blood diseases, or eccentric irritations, are found in connexion with convulsions which they are shown to produce, we ought not to call these latter by the same name.

A mere similarity, or even identity, could that be shown to exist, of the phenomena of convulsions as they occur in different individuals, does not prove the identity of the whole disease from which such individuals are suffering. Such similarity merely shows that the immediate cause of these convulsions is alike in each, whereas the remote causes may differ widely. As dyspnoea may arise from spasmodic asthma, from emphysema of the lung, pneumonia, dilated heart, pleuritis, pleurodynia, anæmia, or from effusion, the result of blood-poisoning, in Bright's disease, so convulsions may occur from a number of conditions, bearing no nearer relation to each other. And as it would be simply absurd and retrogressive to describe the various diseases above-named as different varieties of asthma, so it is equally absurd to describe many of the forms of convulsion as varieties of epilepsy. From a consideration of dyspnoea alone some diagnosis might often be framed, and from a regard to the particular form of convulsive paroxysm, some diagnosis may be aimed at in many cases; but it is from the mode in which these

Diagnosis of Diseases of the Brain, Spinal Cord, Nerves, and their Appendages, p. 174.

D