frequently observed great benefit derived from an emetic,—the vomiting, besides its effects on the circulation, sometimes removing from the stomach undigested food, or evacuating excrementitious fluids.

Mercury combined with antimony, or antimony alone, has a powerful effect in evacuating morbid secretions of mucus which are often met with in the intestinal canal, and these medicines have also a powerful influence in correcting the biliary secretion.

The mercury should always be given cautiously, for, though in some patients decided benefit be derived from a few doses, yet, if carried further, the heart is rendered irritable. Purgatives are also essentially useful remedies in nervous diseases of the heart, and they must be given according to their effects in removing excrementitious matters from the intestinal canal. It is indeed extraordinary, the excitement which the retention of See page 336. fæculent matters sometimes occasion on the heart, and the restoration of its healthy condition whenever they are removed.

The diseases of the genito-urinary system which have so powerful an influence on the heart, may be much relieved by medical treament, and those remedies should be employed which increase, diminish, or improve the qualities of the menstrual Chap. XIX. flux.

CHAPTER XXIV.

THE ORGANIC DISEASES OF THE HEART.

General observations on the organic diseases of the heart—each tissue may be diseased separately, or several may be affected simultaneously; the specific character of organic diseases of the heart; comparative view of the diseases of the right and left hearts; essential differences in the diseases of the pulmonic and systemic hearts; physiological and pathological illustrations; general character of the diseases of the right and of the left heart.

servations.

THUS far I have given a general view of those disturbances of General obthe heart's functions which are caused by alterations in the quantity and qualities of its blood as well as those depending upon disorders of the nervous system. But the functions of the heart are likewise changed by the various morbid alterations in the different tissues of which it is composed, constituting that subdivision which comprehends its organic diseases.

In investigating the organic diseases of the heart, I shall consider all those which affect each particular tissue; at the same time, in the heart as in other organs composed of several distinct tissues, there are many diseases which are not always limited throughout their progress to one, but in which a greater number of its tissues are sooner or later involved.

Diseases may likewise affect the same tissue either of one or of both hearts simultaneously, and, though the functions of the pulmonic and systemic hearts materially differ, yet the component parts of each being nearly alike, their morbid changes are equally similar.

Whenever a change takes place in the structure of any portion of the apparatus of the central organ, there must necessarily be caused some hindrance either to the ready entrance of the venous blood, to the exit of the arterial blood, or the vital stream will be altered in passing through the heart's cavities, from some change that may have taken place in the form of the auriculo

See page 112.

Page 107.

ventricular orifices. Therefore we find that one of the most remarkable effects of a change in the structure of the heart is some change in the distribution of the blood, and this is sometimes caused by a comparatively small structural change, whilst a very extensive disorganisation produces little interruption to the great function of circulation.

Except those morbid changes, which may undoubtedly result from functional diseases long continued, or which are caused by a wound, all the organic affections of the heart, I shall endeavour to show, are decidedly of a specific kind, arising either from gouty or rheumatic inflammation, or from exanthematous diseases, as measles and scarlet fever;-and sometimes, though rarely, from scrofula, fungus hæmatodes, and fungus melanodes.

Comparative view of the diseases of the right and left heart. Reflecting on the numerous diseases of the heart, we are led to inquire, not only into those of its different tissues, but also into the character of those classes of maladies which affect each of the two hearts; and although the elementary tissues which compose both hearts are similar, the muscles of each merely differing in bulk, the endocardium of the left heart resembling the lining membrane of the arteries, and that of the right heart being like that of the veins, we nevertheless find that the diseases of each heart are accompanied with very different phenomena, that the left is far more frequently diseased than the right; and that the two hearts may be considered pathologically distinct from one another.

To comprehend these differences we must refer to the mechanism and functions of the two hearts in the healthy state of the body, and I have already endeavoured to point out at some length in what these differences consist. But whilst a distinct line of demarcation may be drawn between them, still we are never to lose sight of the intimate union of their structures, and of the co-operation in their functions, through the medium of the lungs, in fact, that they are both portions of one complicated machine, any part of which, when once disordered, must more or less influence the functions which are performed by the whole apparatus.

In many affections of the heart this distinction is well marked; for though, as I have said, the functions of the two hearts are intimately blended, yet the systemic circulation may be disturbed without causing much perceptible interruption to the pulmonic circulation; and, vice versa, the pulmonary circulation may be much changed, whilst that of the systemic heart is comparatively little altered.

The differences in the functions of the two hearts it is essential to investigate, when contemplating their disorders; and no pathological phenomena can be more striking than those which may be remarked when either the right or left heart is diseased.

If there be any disturbance in the systemic heart, then we may expect to find either an increase or a diminution in the supply of arterial blood to the different organs; and if there be any disturbance in the pulmonic heart, there will not be necessarily a change in the systemic circulation, but a change in some portion of the venous system.

Thus, whenever the left ventricle does not expel the usual quantity of blood, the vigour of all the organs is diminished; but when the pulmonic heart cannot impel the blood with its usual force through the pulmonary vessels, the venous system becomes congested, marked by a livid colour and coldness of the skin, and a congested state of the subcutaneous veins.

Nothing can be more remarkable than this difference in the disturbances of the circulation in the two hearts,-differences which are readily explained by a reference both to their mechanism and functions.

It is very striking to observe a person whose left heart only is disordered, and to notice how little apparent change there is in all the vital functions when the body is perfectly tranquil, and when from that disease there is a diminished supply of arterial blood to the various organs. For the support of life, it is extraordinary how small a stream of blood seems to suffice. And when the voluntary muscles are placed in a state of relaxation, as happens when the body is in a supine posture, and the respiration is not hurried, there is generally in such cases very little external character of disease. But when there is an interruption to the circulation of the right heart, the congestion of the venous sys

tem, though it be increased by every muscular or respiratory movement, still remains permanent, varying only in degree; so that, however tranquil the body may be, there is always a discolouration of the skin from the varicose state of the veins; a subcutaneous serous effusion, embarrassment in breathing, and difficulty in lying in the horizontal posture, from the congested state of the pulmonary capillaries.

Nothing can be more characteristic of the differences in the diseases of the two hearts, than those means which the animal economy employs to relieve the symptoms of each. This we may observe exemplified in the hurried respiration and increased impetus of the heart, when the left ventricle is overloaded, and in the sobbing and sighing and deep inspirations, when the pulmonic heart and venous systems are gorged with blood.

The curative effects of spontaneous hæmorrhages also point out differences in each heart. We see how much the portal system and the congested pulmonic heart are all relieved by the hemorrhoidal flux; how a congestion of the systemic heart is relieved by epistaxis; how pulmo-cardiac congestion is relieved by hæmoptysis; and these different modes which the vis medicatrix employs to relieve the pulmonic and systemic hearts from congestion, points out an important law of the animal economy, which we should imitate in the treatment of diseases; to abstract blood from the cardiac region, or æthmoidal vessels, when the left heart is gorged with blood; and from the hæmorrhoidal vessels, when the right heart and venous system are congested.