this condition, that a stronger exertion of it is necessarily followed by a weaker state of the same. It seems to depend upon this law in the constitution of the nervous power, that the ordinary contraction of a muscle is always alternated with a relaxation of the same; that, unless a contraction proceeds to the degree of spasm, the contracted state cannot be long continued: and it seems to depend upon the same cause that the voluntary motions, which always require an unusual increase of exertion, occasion fatigue, debility, and at length irresistible sleep.

From this law, therefore, of the nervous power, we may understand why a sudden and violent exertion of the energy of the brain is sometimes followed by such a diminution of it as to occasion a syncope; and it is thus I suppose that a violent fit of joy produces syncope, and even death. It is upon the same principle also, I suppose, that an exquisite pain may sometimes excite the energy of the brain more strongly than can be supported, and is therefore followed by such a diminution as must occasion fainting. But the effect of this principle appears more clearly in this, that a fainting readily happens upon the sudden remission of a considerable pain; and thus I have seen a fainting occur upon the reduction of a painful dislocation.

1179.] It seems to be quite analogous when a syncope immediately happens on the finishing of any great and longcontinued effort, whether depending on the will, or upon a propensity; and in this way a fainting sometimes happens to a woman on the bearing of a child. This may be well illustrated by observing, that in persons already much weakened, even a very moderate effort will sometimes occasion fainting.

1180.] To explain the operation of some other causes of syncope, it may be observed, that as the exertions of the energy of the brain are especially under the influence of the will, so it is well known that those modifications of the will which are named Passions and Emotions, have a powerful influence on the energy of the brain in its action upon the heart, either in increasing or diminishing the force of that energy. Thus, anger has the former, and fear the latter effect; and thence it may be understood how terror often occasions a syncope sometimes of the most violent kind, named Asphyxia, and sometimes death itself.

1181.] As, from what I have just mentioned, it appears, that the emotions of desire increase, and those of aversion

diminish the energy of the brain; so it may be understood, how a strong aversion, a horror, or the feeling which arises upon the sight of a very disagreeble object, may occasion fainting. As an example of this, I have known more than one instance of a person's fainting at the sight of a sore in another person.

1182.] To this head of horror and disgust, I refer the operation of those odours which in certain persons occasion syncope. It may be supposed, that those odours are endowed with a directly sedative power, and may thereby occasion syncope; but they are, many of them, with respect to other persons, evidently of a contrary quality; and it appears to me, that those odours occasion syncope only in those persons to whom they are extremely disagreeable.

1183.] It is, however, very probable, that among the causes of syncope, there are some which, analogous to all those we have already mentioned, act by a directly sedative power: And such may either be diffused in the mass of blood, and thereby communicated to the brain; or may be only taken into the stomach, which so readily and frequently communicates its affections to the brain.

1184,] Having now enumerated, and, as I hope, explained the most part of the remote causes of syncope, that either operate immediately upon the brain, or whose operation upon other parts of the body is communicated to the brain, it is proper to observe, that the most part of these causes operate upon certain persons more readily and more powerfully than upon others; and this circumstance, which may be considered as the predisponent cause of syncope, deserves to be inquired into.

It is in the first place, obvious, that the operation of some of those causes depends entirely upon an idiosyncrasy in the persons upon whom they operate; which, however, I cannot pretend to explain. But, in the next place, with respect to the greater part of the other causes, their effects seem to depend upon a temperament which is in one degree or other in common to many persons. This temperament seems to consist in a great degree of sensibility and mobility, arising from a state of debility, sometimes depending upon original conformation, and sometimes produced by accidental occurrences in the course of life.

1185.] The second set of the remote causes of syncope (1174.) or those acting directly upon the heart itself, are certain organic affections of the heart itself, or of the parts

immediately connected with it, particularly the great vessels which pour blood into, or immediately receive it from, the cavities of the heart. Thus a dilatation or aneurism of the heart, a polypus in its cavities, abscesses or ulcerations in its substance, a close adherence of the pericardium, to the surface of the heart, aneurisms of the great vessels near to the heart, polypus in these, and ossifications in these or in the valves of the heart, are one or other of them conditions which, upon dissection, have been discovered in those persons who had before labored under frequent

syncope.

1186.] It is obvious, that these conditions are all of them, either such as may, upon occasion, disturb the free and regular influx into, or the free egress of the blood from, the cavities of the heart; or such as may otherwise disturb its regular action, by sometimes interrupting it, or sometimes exciting it to more violent and convulsive action. The latter is what is named the Palpitation of the Heart, and it commonly occurs in the same persons who are liable to syncope.

1187.] It is this, as I judge, that leads us to perceive in what manner these organic affections of the heart and great vessels may occasion syncope: for it may be supposed, that the violent exertions made in palpitations may either give occasion to an alternate great relaxation, (1178.) or to a spasmodic contraction; and in either way suspend the action of the heart, and occasion syncope. It seems to me probable, that it is a spasmodic contraction of the heart that occasions the intermission of the pulse so frequently accompanying palpitation and syncope.

1188.] Though it frequently happens that palpitation and syncope arise, as we have said, from the organic affections above mentioned, it is proper to observe, that these diseases, even when in a violent degree, do not always depend on such causes acting directly on the heart, but are often dependent on some of those causes which we have mentioned above as acting primarily on the brain.

1189.] I have thus endeavored to give the pathology of syncope; and of the cure I can treat very shortly.

The cases of syncope depending on the second set of causes, (1174.) and fully recited in 1185, I suppose to be generally incurable; as our art, so far as I know, has not yet taught us to cure any one of those several causes of syncope (1185.)

The cases of syncope depending on the first set of causes, (1174.) and whose operation I have endeavored to explain in 1177. et seq. I hold to be generally curable, either by avoiding the several occasional causes there pointed out, or by correcting the predisponent causes (1184.) The lat ter, I think, may generally be done by correcting the debility or mobility of the system, by the means which I have already had occasion to point out in another place.*

CHAPTER II.

OF DYSPEPSIA, OR INDIGESTION.

1190.] A WANT of appetite, a squeamishness, some

times a vomiting, sudden and transient distentions of the stomach, eructations of various kinds, heartburus, pains in the region of the stomach, and a bound belly, are symptoms which frequently concur in the same persons and therefore may be presumed to depend upon one and the same proximate cause. In both views, therefore, they may be considered as forming one and the same disease, to which we have given the appellation of Dyspepsia, set at the head of this chapter.

1191.] But as this disease is also frequently a secondary and sympathic affection, so the symptoms above-mentioned are often joined with many others; and this has given occasion to a very confused and undetermined description of it, under the general title of Nervous Diseases, or under that of Chronic Weakness. It is proper, however, to distinguish them; and I apprehend the symptoms enumerated above are those essential to the idiopathic affection I am

now to treat of.

1192.] It is indeed to be particularly observed, that these symptoms are often truly accompanied with a certain state of mind which may be considered as a part of the idiopathic affection: but I shall take no further notice of this symptom in the present chapter, as it will be fully and more properly considered in the next, under the title of Hypochondriasis.

1193.] That there is a distinct disease attended always with the greater part of the above symptoms, is rendered very probable by this, that all these several symptoms may

See article 217, &c.

arise from one and the same cause; that is, from an imbecility, loss of tone, and weaker action in the muscular fibres of the stomach: and I conclude, therefore, that this imbecility may be considered as the proximate cause of the disease I am to treat of under the name of Dyspepsia. 1194.] The imbecility of the stomach, and the consequent symptoms, (1190.) may, however, frequently depend upon some organic affection of the stomach itself, as tumor, ulcer, or schirrosity; or upon some affection of other parts of the body communicated to the stomach, as in gout, amenorrhoea, and some others. In all these cases, however, the dyspeptic symptoms are to be considered as secondary or sympathic affections, to be cured only by curing the primary disease. Such secondary and sympathic cases cannot, indeed, be treated of here: but as I presume that the imbecility of the stomach may often take place without either any organic affection of this part, or any more primary affection in any other part of the body; so I suppose and expect it will appear, from the consideration of the remote causes, that the dyspepsia may be often an idiopathic affection, and that it is therefore properly taken into the system of methodical Nosology, and becomes the subject of our consideration here.

1195.] There can be little doubt, that in most cases, the weaker action of the muscular fibres of the stomach, is the most frequent and chief cause of the symptoms mentioned in (1190.) but I dare not maintain it to be the only cause of idiopathic dyspepsia. There is, pretty certainly, a peculiar fluid in the stomach of animals, or at least a pe culiar quality in the fluids, that we know to be there, upon which the solution of the aliments taken into the stomach chiefly depends: and it is at the same time probable, that the peculiar quality of the dissolving or digesting fluids may be variously changed, or that their quantity may be, upon occasion, diminished. It is therefore sufficiently probable, that a change in the quality or quantity of these fluids may produce a considerable difference in the phenomena of digestion, and particularly may give occasion to many of the morbid appearances mentioned in 1190.

1196.] This seems to be very well founded, and points out another proximate causes of dyspepsia beside that we have already assigned: but, notwithstanding this, as the peculiar nature of the digestive fluid, the changes which it may undergo, or the causes by which it may be changed,