Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/588

554 permanently to contract many dilated hearts, and so to cure what seemed an incurable disease not only to Senac but even to many of his more modern successors. There are many other drugs employed in the treatment of diseases of the heart, but there is no other deserving of special mention. Other medicines are employed to relieve pain, aid digestion, dispel flatulence, unload the bowels, improve the blood, or simply as general tonics, and may be catalogued as morphia, chloroform, belladonna, pepsine, asafoetida, aloes, rhubarb, iron, &c.

is a painful disease of the heart which has been already described. Palpitation is an extremely rapid and sometimes forcible action of the heart. Irregular and Intermittent Action are sufficiently described by their names ; irregular action may be tumultuous or so peculiar as to deserve the name of a veritable delirium cordis ; intermission consists in the dropping of a beat every second, third, or fourth time, or seldomer. Some times the intermission only applies to the pulse, the heart acting regularly, and is caused by that particular systole not being forcible enough to propel the blood to the periphery ; occasionally we have two beats of the pulse and then an intermission, constituting what has been termed a pulsus bigeniinus, or the rhythm of the intermission maybe even more varied. All these forms of perverted action of the heart may accompany valvular lesions, or they may occur in hearts whose valves are sound ; the walls of such hearts are, however, almost invariably more or less feeble, imper fectly nourished, and the blood often poor and watery. They are rarely indicative of any real danger, though sufficiently troublesome and alarming to the sufferer; they arise from abnormal innervation, and are part of the penalties we pay for our present state of organization. We could enjoy nothing if we could not also suffer; and the blush of sensitiveness, the quickened pulse of affection, are paid for by the throb of anxiety, and the fatal inhibition of the heart s action due to overwhelming emotion. Most of these cases, however, own a much more ignoble origin : a flatulent distention of the stomach, a crapulous dyspepsia, the abuse of alcohol and tobacco, &c., are frequent sources of nervous heart trouble, so frequent that in some parts where young men most do congregate the tobacco-heart especially is quite a proverbial ailment. Overwork, worry, or excess of any kind is sufficient to bring on heart trouble of this character, as we can readily understand when we reflect that the heart does about one-fifth of the whole mechanical work of the body a work equivalent to raising its own weight over 13,000 feet an hour; that it takes its rest only in short snatches as it were, its action as a whole being continuous ; and that it must necessarily be the earliest sufferer from any improvidence as regards nutrition, mental emotion being in this respect quite as potential a cause of constitutional bankruptcy as the most violent muscular exertion. Fortunately, to a skilled physi cian there is no difficulty of determining the true nature of these cases, and they are all more or less amenable to appro priate treatment. Syncope, or fainting, is an affection somewhat similar to those just described ; it essentially consists in an emotional inhibition of the cardiac systole, so that the blood pressure within the brain falls below that necessary for the maintenance of consciousness ; as the heart s action fortunately does not in these cases entirely cease, the best plan is to favour the flow of blood to the head by maintaining the sufferer with a lowered and slightly depending head until the effects of the momentary inhibition have passed off. The inflammatory affections of the heart, Carditis, Endocarditis, and Pericarditis are most important and serious affections, but their history and treatment are more suited for a work on practice of physic, in any of which full information regarding them may be found. They are mainly rheumatic and gouty in character, and they are to be regarded as varieties of these diseases ; the mere fact of their affecting the heart is of but little consequence as to their immediate result, however important it may by and by become from the valvular lesions to which they so often give rise. There are but few exceptions to this rule, and amongst them are those rare cases in which acute endarteritis blocks the coronary vessels and gives rise to fatal angina. Fatty Degeneration of the heart, which bulks so largely in the popular mind as a cause of sudden death, is an almost hypothetical lesion of most infrequent occurrence, probably never found apart from disease of the coronary arteries, impossible of diagnosis, and very rarely of itself proving suddenly fatal.    

WILLIAM THOMSON.

   EAT is a property of matter which first became known to us by one of six very distinct senses.

§ 1. Sense of Heat.—The sense of touch, as commonly meant, has two distinct obj ects force and heat. If a person stretches out his hand till it meets anything solid, or holds it out while something solid is placed upon it, he experi ences a sensation of force. He perceives resistance to the previous motion of his hand in one case, in the other case the necessity of resisting to prevent his hand from being forced downwards ; the immediate object of this perception in each case is force. But there is another very distinct sensation, that of heat or cold, which he may or may not perceive in either of those cases, and which he may also perceive, still by what is commonly called the sense of touch, in other cases even when no sense of force is also experienced. Thus, in the first case, if the solid be a fixed can of warm water, or of iced water, the person perceives a sense of heat or of cold ; and, supposing him to have per formed the operation with his eyes shut, his mind is informed by the double sense of touch that his hand has met with a hot fixed body or a cold fixed body : in the other case he may perceive that a hot heavy solid, or a cold heavy solid, has been laid upon his hand. But if he dips his hand gently into a can of water, or if he holds it towards a fire, or if he exposes it to a gentle current of air, or waves it about through the air, he perceives heat or cold without any accompanying sense of force. The earliest scientific thoughts respecting these sensations of heat and cold must have led to the true conclusion that there is some property of external matter on which the sensations depend, and a little advance into the natural philosophy of the subject has suggested and proved that this property is also possessed by the living body, and that the sensation of heat or cold in the hand, in the instances 