accumulation of fluid or air in the cavity of the pleura, the displacement being to the right when the mischief is on the left side, and vice versa. Extensive emphysema confined to one lung may, to some extent, produce the same effect. Sometimes, subsequent to the subsidence of acute disease in the pleural cavity, the heart is dragged over by the contraction of the effused lymph to the side on which the mischief occurred. Disease of the lung substance, leading to atrophy or diminution of bulk in the pulmonary tissue, may also occasion lateral displacement towards the side in which the atrophy occurs,* and chronic effusion into the pericardium, which pushes the base of the heart backwards as well as upwards, and causes the whole organ to assume a more than ordinarily horizontal posture, leads to the apex pulsating far to the left of its normal position. Emphysema of the anterior part of the lung, aneurismal tumours which insinuate themselves between the heart and the anterior surface of the chest, and malignant, scrofulous, and other tumours in the anterior mediastinum, push the heart backwards, and in some instances prevent the impulse of its apex against the chest.

The extent of surface over which pulsation can be seen varies immensely. Ordinarily the impulse of the apex of the heart occasions the only pulsation which is visible on the chest walls, and the area over which that extends does not exceed a square inch. But in certain cases of hypertrophy and dilatation the heart may be seen beating over the whole præcordial region, from the third to the sixth or even the seventh intercostal space; whilst in certain cases of pericarditis with abundant effusion, an undulatory movement, which is synchronous with the systole of the heart, and passes from below upwards, is visible in one or all of the intercostal spaces from the second to the sixth. When the heart is weak and excessively dilated, and adherent to the anterior walls of the chest, this movement may be simulated by the action of the heart itself, but when it is well marked it is very distinctive of pericardial effusion. Again, in cases in which the pericardium has contracted adhesions to the chest walls, and the heart remains of its normal size, pulsation coincident with the pulsation of the apex may be visible in the fourth intercostal space; and yet again aneurismal or other tumours may occasion extensive pulsation on the chest walls—not necessarily

* I have seen this occur on several occasions when great atrophy of one lung, consequent on tubercular deposit and excavation, occurred coincidently with emphysema of the other lung. One remarkable case of this sort which occurred under my care at St. George's Hospital, is recorded in the 'Trans. Path. Soc.,' vol. xi, p. 15.

in the præcordial region.

Further, in certain instances of phthisis, in which the lung has been excavated by vomicæ, the pulmonary artery may come into contact with the chest, and communicate a pulsation to the second left intercostal space. In this case, as in that of aneurismal and other tumours which give rise to pulsation, there are two distinct seats of systolic impulse, which correspond respectively with the apex of the heart and the pulsation produced by the vessel or the tumour.

In certain instances a retraction or sinking in of the fourth left intercostal space is observed at the same time that the ordinary impulsive forward movement which accompanies the systole of the heart is taking place in the fifth intercostal space. This has been attributed by some authorities to adhesion of the two surfaces of the pericardium, and by others to simple hypertrophy and dilatation of the heart. My own observations induce me to believe that neither of these forms of disease will produce it, when the surrounding structures are in their normal condition, and to assert that when this double movement is observed it is primarily due to agglutination of the heart to the anterior parietes of the chest as a result of a former attack of inflammation, under which circumstances adhesion of the two layers of the pericardial membrane and extensive dilatation of the heart will give rise to it, sometimes in a very marked degree.

It will be observed that I have attributed pulsation in the fourth left intercostal space, occurring coincidently with pulsation at the apex, to adhesion of the pericardium to the anterior surface of the chest, and have referred the retraction of the parietes sometimes observed in the same position to the influence of the same cause—a circumstance which appears to involve a contradiction. But in truth the two facts are quite consistent and strictly in keeping with pathological research. In the one case the heart is not enlarged, in the other it is exceedingly dilated, so that a different part of the organ is in contact with the fourth interspace in the two cases. I have verified this observation by post-mortem examination in several instances, and entertain no doubt as to its correctness.

Irregularities in the rhythm of the impulse produced by the heart are observed during the diastole of the heart as well as during its systole. Thus, when from any cause the left lung is retracted and the left auricle enlarged, a diastolic impulse is sometimes visible in the second or third left intercostal space, referable to the contraction of the auricle. Again, instead of the single impulse ordinarily produced by the apex of

the heart, or the double systolic impulse already described, there is sometimes a double impulse-the one synchronous with the systole of the heart, the other occurring during the diastole. The former is visible in the fifth intercostal space, and is caused by the impulse of the apex; the other or backstroke is visible in the fourth intercostal space, and is due to the pulsation of the right ventricle during its expansion. This peculiar see-saw movement is characteristic of hypertrophy and dilatation of the heart, with or without adhesion of the pericardium to the anterior surface of the chest. In some instances hypertrophy of the heart, especially when occurring in thin persons with a short sternum, gives rise to falling in of the epigastrium during the systole of the heart. Distension of the large veins of the neck, especially the external jugular, is another phenomenon which inspection informs us of. It arises from pressure upon the superior cava or the vena innominata by aneurismal or other intra-thoracic tumours, or from obstruction to the circulation through the right side of the heart. When it is accompanied by pulsation it indicates insufficiency of the tricuspid valve, and of the valves seated at the junction of the internal jugular and subclavian veins. Hence it is a symptom of a largely dilated right ventricle, or of regurgitant disease of the tricuspid valve. It must be remembered, however, that even in these forms of disease pulsation of the jugulars will not ordinarily be observed until the cardiac mischief has existed for some time, and has given rise to distension of the veins sufficient to render their valves inefficient. The only exception to this is when the valves in the veins are ruptured and inoperative, in which case pulsation may be observed in an early stage of the cardiac disorder.

CHAPTER III.

PALPATION, OR THE APPLICATION OF THE HAND.

PALPATION, or the application of the hand to the cardiac region, enables us to determine the position of the apex of the heart, the force with which it comes in contact with the chest, and the rhythm of its pulsation. It informs us of the movement of the ribs and of the state of vocal vibration in the præcordial region, and in certain instances it makes us aware of the existence of abnormal pulsation referable to

disease in the heart or great vessels, or of a thrill due to cardiac, pericardial, or arterial disease.

There is little to be noted by palpation respecting the impulse of the heart during health, except that it ordinarily has a certain force, is single, regular in rhythm, and synchronous with the systole of the ventricle, and occurs in the same position as the visible impulse on the chest walls; that in broad-chested, stout persons, it may be hardly perceptible, and in narrow-chested, thin persons, and in women and children, may be comparatively strong; that it is greatly increased by mental emotions, and by whatever quickens the respiration or accelerates the circulation, and that it is apparently stronger during expiration than during inspiration, when the lungs are fully inflated, and press between the heart and the chest walls.

Further, it informs us that a variety of morbid influences may induce variation in the force, character, and extent of the impulse, quite irrespectively of disease in the heart itself. It proves that when the lungs are emphysematous and press between the heart and the chest walls, the impulse is diminished or altogether annihilated; that a similar effect is observed when the heart is acting feebly, as in adynamic disorders, and when the patient is under the influence of aconite and other medicinal agents which depress the circulation-in other words, when the heart is acting feebly; as also when large, inelastic tumours occupy the anterior mediastinum, and by their bulk and want of elasticity prevent the transmission of impulse.

In like manner it shows that even when the heart is healthy there may be increased force and extent of pulsation, due to the increased facility with which the heart's impulse is transmitted to the chest walls, in consequence of pleuritic retraction of the parietes, or of consolidation of the lung tissue, or of the upward pressure of an enlarged liver or spleen, or of a greatly distended stomach or abdomen, or of the presence of small tumours in the anterior mediastinum, which are better conductors than spongy, air-distended lung. In short, it teaches us the practical lesson that increased cardiac impulse does not necessarily indicate organic disease of the heart. This is a fact which ought never to be forgotten; for if cases such as these are mistaken, as they often have been, for instances of diseased heart, an improper treatment cannot fail to be adopted. Though characterised by increased parietal pulsation, they are not accompanied by irregularity or increased force in the heart's action, and careful stethoscope exami

nation, by revealing the absence of cardiac mischief, will generally serve to elucidate their true nature.

On the other hand, palpation proves that the heart's impulse may be greatly increased and the area of pulsation extended under a variety of morbid conditions connected with the heart and great vessels, and quite independently of external influences. The extent to which this occurs varies immensely; but to such a degree may the force of the impulse increase, that it may even shake the whole body of the patient, and impart a strong jogging motion to the head of the auscultator when placed on a stethoscope applied to the cardiac region. The area of pulsation may also undergo a corresponding extension, so that almost the whole anterior surface of the chest may heave, and pulsation may be distinctly felt on the left side of the back.

The causes of increased cardiac impulse are functional palpitation, inflammation, whether of the heart or the pericardium, and hypertrophy of the heart. Simple hypertrophy produces a great increase of impulse; hypertrophy with dilatation leads not only to increased impulse, but to an extension of the area over which it is felt. Aneurismal dilatation of the aorta or other great vessels may occasion a heaving impulse in almost any part of the thoracic walls, but is especially prone to do so on the anterior surface of the chest. In some of these instances the impulse conveys the impression of being accompanied by alternate expansion and contraction. Sometimes, again, a pulsation may exist in the second left intercostal space, which the hand perceives to be synchronous, or nearly so, with the impulse of the apex; whilst in other cases a pulsation is felt in the second or third left intercostal space, which in point of time precedes the impulse of the apex. In the former instance the phenomenon may be due to the systole of the pulmonary artery felt in that position, in consequence of retraction of the lung caused by excavation of the pulmonary tissue; in the latter it is referable to the systole of an hypertrophied left auricle.

It has been attempted to diagnose the nature of the cardiac lesion by noting the position of the increased impulse and the direction in which it is traceable. But a variety of extraneous causes may lead to the heart's pulsating a little further to the right or to the left, or to its lying more or less horizontally in the chest; and it needs little experience to prove that such data do not afford trustworthy grounds for an opinion. Indeed the hand alone will not even serve in all cases to distinguish cardiac from aneurismal pulsation.