after they have existed for a time and as they grow. 2. They cause pressure on distant parts, which, in its turn, causes an alteration of structure and nutrition. 3. They set up progressive disease and degeneration of certain parts of the nerve structure, such as optic neuritis, the true nature of which is not yet very well known; but it seems to be in some way directly connected with the essential constitution and nature of all sorts of nerve substance, whether cells or fibres. And lastly, that all cases of insanity from organic brain disease seem to hold an intermediate place, so far as mental symptoms are concerned, between acute inflammation of the cortical substance and blood poisonings on the one hand, and ordinary typical insanity on the other, the mental characteristics of the three being represented by delirium, irritability, and delusion respectively.

The Hereditary Insanity of Adolescence. This is a long name and a somewhat clumsy one, but I cannot devise a better. In a conversation I had with Dr. Skae before his death, in reference to the influence of hereditary predisposition, he agreed with me that there was a very distinct form of insanity that we often meet with in the members of families strongly tainted with a neurotic inheritance, about the age of 20, or from 18 to 25, just as the patient is coming to maturity. Usually no cause whatever can be assigned for the coming on of the disease. In very many cases the patients have been most promising and healthy up to the time of the attack. In comparison with their brothers and sisters they have frequently been the most steady and studious. In fact, such persons come to maturity sooner than usual, and have been more free from youthful livelinesses, and less drawn to the other sex. They have been men and women almost before their time. The form of insanity that attacks them is always a sharp attack of maniacal excitement, coming on suddenly, and, as I remarked, usually without any sort of real assignable cause. Anxious parents will be sure to devise a cause of some sort. They have been too studious, they have worked too hard, they have not taken amusement or exercise enough, they have had a cold or some trifling ailment. In cases of this sort, almost more than any others, are the bright hopes and fond anticipations of parents blasted and crushed; for the majority of such cases never recover at all, and those who do are very apt to have relapses. After a short attack of excitement the mania passes away, leaving the mental powers dulled and weakened, and after a few

irregular spurts of excitement or transitory brightenings up, the patient sinks into hopeless dementia, but with excellent bodily health, so that he lives apparently as long as though the brain functions had remained perfect. Such cases form a considerable part of the dements that fill our asylum wards. This variety of insanity is, I think, quite a distinct and wellmarked one. It is the purest type of hereditary insanity, and might be well called simply by that name, if that would not be likely to lead to confusion. It seems as though such persons had in the twenty years they have lived exhausted the original power of their brain convolutions. They are examples of like begetting like, for in most cases insanity has occurred in ancestors not far removed. They only inherited brain power enough to carry them up into adolescence, instead of having, like an ordinary human being, enough to last while the rest of the body lasts. It is a sort of premature dotage of the brain between 18 and 25. They have thus died in their youth to all the passions, the cares, and human interests that occupy other men. It is an example of Nature's mode of stopping the reproduction of disease. hard on the individual, it is certainly good for the race. In fact, I think I have often observed that all the hereditary taint in a family seemed to go to such a case, while all the rest of the members of it remained quite free from neurotic symptoms. I have thought it a good sign for the others, if one of a family was thus affected. He was the scapegoat for the rest.

However

Idiopathic Insanity.-By this term Dr. Skae meant every case of insanity caused by purely mental or moral causes that did not come under any of his other varieties. He thought that in nearly all cases the exhaustion of brain produced by want of sleep was the immediately exciting cause of the disease. Contrary to the common belief that insanity is usually the result of severe disappointments, anxieties, afflictions, and distresses of life, we find, as a matter of fact, that only about one-fourth of all the cases are so caused, and of these about two-thirds can be usually referred to some of Dr. Skae's varieties, leaving about one-tenth or one-twelfth of the total number of the insane that are really idiopathic.

This variety Dr. Skae divided into two kinds: the sthenic and the asthenic, which he thus distinguishes: "Sthenic, when combined with distinct symptoms of vascular action-suffused eye, throbbing temples and carotids, hard and full pulse, occurring in persons in robust health, and brought on most

commonly by causes of a nature calculated to excite the emotions and passions. Asthenic, when combined with symptoms of Anaemia-emaciation, feeble pulse, cold extremities, and so forth; and brought on by causes conducive to an anæmic condition-exhaustion, and especially want of sleep, however induced, whether by grief, anxiety, over-taxed brain, poverty and starvation.

Such is a very imperfect sketch of the different varieties of insanity which Dr. Skae thought deserved to be reckoned as distinct natural orders.

And now permit me, Mr. President and Gentlemen, to thank you very cordially for the respect you have paid to Dr. Skae's memory, and the honour you have done me by your attendance at this course of lectures.

On Syphilitic Affections of the Nervous System. By J. HUGHLINGS JACKSON, M.D., F.R.C.P., Physician to the London Hospital, and to the Hospital for the Epileptic and Paralysed.

I wish here to give as briefly as possible an account of the pathology of the nervous symptoms which result from syphilis. Of necessity there is considerable recapitulation from former papers I have written. For syphilis produces very different affections of the nervous system, and I have therefore had to speak of syphilis when considering Amaurosis, Epileptiform seizures, Hemiplegia, &c. It is, however, justifiable to bring together the conclusions one has arrived at about syphilitic nervous affections from the study of nervous affections in general.

A great deal of work has now been done, both in this country and abroad, on syphilitic diseases of the nervous system, and recently there have appeared the masterly lectures by Broadbent, and the most valuable book by Buzzard on these affections. It is a very difficult task to write on such a subject after these able physicians. I shall, therefore, limit myself. I wish simply to consider syphilitic nervous affections as I have seen them myself; thus my task is considerably narrowed.*

* Of syphilitic disease of the spinal cord, however, I do not wish to say anything, because I have not yet seen a single case as proved post mortem. There are very few cases of this kind with post mortem examinations on record; there ought, therefore, to be more hesitation than there is in ascribing paraplegia to syphilis.

My main object is to show that most syphilitic affections of the nervous system are very indirectly of nervous origin, and therefore that such names as Syphilitic Hemiplegia, Syphilitic Epilepsy, Syphilitic Insanity, although convenient for use in purely empirical arrangements for direct utilitarian purposes, are not scientifically accurate. They are analogous to terms used by the gardener, not to terms used by the botanist. If used in scientific statements, as I suppose for lack of others they will be, great confusion must result if we let the names be other than mere conventional labels. Just as confusion would result if the gardener's convenient terms (fruit trees, flowers, vegetables, and shrubs) were used in what purported to be a scientific account of plants. The pathological processes leading to the nervous symptoms mentioned as being syphilitic are really complex. Moreover, the conditions of nervous organs, which are the direct causes of the several nervous symptoms, are very different. The matter is not simple as the simple nomenclature implies. The terms mentioned are sometimes used as if they embodied clear pathological accounts; those who so use them evidently do not even know that they do not know the pathology of the cases of which they speak so easily.

I do really think, however, that empirical arrangements of cases of nervous disease by their most prominent features, or by signs guiding to utilitarian procedures are justifiable. Nay, I think that for practical purposes clinical entities are essential. I have much changed my opinions on this matter since reading an able paper by Moxon on Classification of Disease (Guy's Hospital Rep. Vol. xv.) Of some morbid states we have not enough knowledge to make a scientific classification-dyspepsia, for example. Let me give an illustration of the value of the empirical arrangement in cases of disease of the nervous system. Contrary to what I used to believe, I believe now that it is desirable for preliminary diagnosis to arrange cases of epilepsy and epileptiform convulsion according to what is the most striking feature in the cases. But scientifically the classification of epilepsies should, I think, depend on the principle that any part of the cerebral cortex may become unstable, and may discharge. For practical purposes, however, for diagnosis, for example, we must have an arrangement of cases from their most striking features, e. g., into epileptic vertigo, epilepsy proper, &c. A patient comes to us for certain symptoms, for vertigo we will suppose; we have first to consider it as vertigo simply, in order

to find out whether it be epileptic, ocular, auditory, &c. Similarly for insanity; an empirical arrangement is, I submit, necessary for diagnosis and treatment. We should have Syphilitic Insanity, Phthisical Insanity, and the like. For obviously the most important thing for direct utilitarian purposes is the pathology and the causation. But the misfortune is that such arrangements may be taken for classifications properly so-called. They are really only provisional groupings for mere convenience. Because it is convenient to consider a whale as a fish for legal purposes, it would never do to consider it so in zoology. The only scientific basis for a genuine classification of insanity, that is, one analogous to the botanist's classification, is, I submit, the principle of Dissolution, the word dissolution being here used as the opposite of Evolution. For besides more direct reasons, this principle applies to most varieties of disease of the brain-to aphasia, hemiplegia, epileptic mania, and insanity ordinarily so called. But then this classification, valuable as a means of extending our knowledge, would be useless, or of little use, for direct practical purposes. For these we must have a clature and an arrangement analogous to that of the gardener.

nomen

Whilst showing that the pathological processes by which syphilis causes nervous symptoms are usually complex and indirect, I shall show also that in these respects they simply imitate non-syphilitic morbid processes. I make this remark chiefly because I wish to give a reason for speaking in what follows more generally of nervous symptoms than the title syphilitic affections seems to warrant. Thus, what I shall call the Second Variety of Hemiplegia from Syphilis (that due to thrombosis of a syphilitic artery) does not differ from hemiplegia, owing to thrombosis of an atheromatous artery. Again, a syphilitic tumour in the brain acts like any other kind of tumour; and thus it would be most misleading to speak of the symptoms of it without regard to the fact that a glioma, an abscess, or an hydatid cyst, produce the same symptoms. The principle applies to every nervous symptom which syphilis produces. There is nothing in any kind of nervous symptom which enables us to diagnose syphilitic disease of the nervous system; our diagnosis is founded on associations and successions of symptoms; that is, of course, apart from obvious signs of external syphilis, which indeed make the diagnosis for us.