and dilatation of the heart. In these cases, the enlargement and consequent dulness extends its limits to the right or to the left, according as the right or left chambers of the heart are affected. From the same cause, the area and force of cardiac pulsation are after a time increased, though the impulse in most well-marked cases is irregular both in force and rhythm.

But beyond this, it is necessary to observe that disease at the various orifices operates very differently in many particulars.*

Obstruction of the aortic orifice is a common form of mischief.† It has little effect in producing engorgement of the pulmonary capillaries, or in occasioning general systemic congestion and dropsy; nay more, the greatest constriction of this orifice may be unattended by these symptoms. It is not until after the left ventricle has become dilated, and the mitral valve consequently so inefficient as to admit of regurgitation, that symptoms of pulmonary and systemic obstruction begin to manifest themselves. Aortic constriction therefore, cæteris paribus, is the least rapidly fatal form of valvular disease. In cases of moderate obstruction the character of the pulse is not materially altered; but when the obstruction is great, the pulse is small, though regular in force and frequency. When the action of the heart is forcible, and the obstruction is rough, and of a nature to cause excessive eddying of the blood, it may give rise to thrill at the base of the heart, and in the track of the aorta and its branches.

Obstruction of the mitral orifice is comparatively rare.‡ It necessarily induces dilatation of the left auricle, and not unfrequently hypertrophy also, with pre-systolic auricular impulse. At the same time, the action of the heart becomes rapid and tumultuous, the pulmonary system becomes congested, and the right ventricle and pulmonary artery are dilated and hypertrophied in consequence. It is therefore productive of severe cough, breathlessness, and other peculiarly distressing symp

* As evidence of the relative frequency with which the various valves are affected, I may refer to the valuable statistics collected by my colleague, Dr. Barclay, from the records in the Museum of St. George's Hospital. He has shown that amongst seventy-nine cases of valvular disease the mitral and aortic valves were both affected in thirty-six instances; the aortic was affected alone in twenty-six, and the mitral alone in seventeen instances. In this series of cases the valves on the right side of the heart were not once affected. (See 'Med.-Chir. Trans.,' vol. xxxi.) I would also refer the reader to Dr. Ormerod's admirable 'Gulstonian Lectures on the Pathology of Valvular Disease of the Heart.'

† For the characteristics of obstructive aortic murmur, see ante, pp. 52 and 101. For the characteristics of obstructive mitral murmur, see ante, pp. 55 and 102.

toms, and proves rapidly fatal with congestion and oedema of the lungs, and not infrequently with pulmonary apoplexy. The pulse is small, but not necessarily irregular.

Obstruction of the pulmonary orifice is seldom met with.* It does not influence the radial pulse, nor does it in the first instance produce congestion of the venous system, but it leads after a time to hypertrophy and dilatation of the right ventricle, and in this way ultimately gives rise to regurgitation, through the tricuspid orifice, with turgescence and pulsation of the large veins in the neck. Until this occurs, it does not occasion urgent or distressing symptoms.

Obstruction of the tricuspid orifice is exceedingly rare.† I have only met with one instance in point, and practically therefore can say little about it, but theoretically, it would lead to hypertrophy and dilatation of the right auricle and excessive congestion of the venous system, unaccompanied by any visible pulsation in the neck. Somnolence, headache, and dropsy, would be amongst its most prominent symptoms. The radial pulse would not be primarily influenced by its occur

rence.

Regurgitation through the aortic orifice is not an uncommon form of valvular disease. It speedily gives rise to hypertrophy of the left ventricle, but does not produce embarrassment of the pulmonary circulation, until dilatation of the left ventricle has reached a point at which the mitral valve proves unequal to close the dilated auriculoventricular opening, and admits of regurgitation through it. Therefore for a considerable length of time it does not materially impede the systemic capillary circulation, and fails to produce dropsy or other distressing symptoms.

It is accompanied by a peculiar and characteristic pulse. It is not the small pulse of aortic obstruction, nor the unequal and irregular pulse of mitral regurgitation; but in its most marked and most striking character it is the unsustained pulse of unobstructed arteries. There is, in this case, no impediment to the onward current of the circulation, no lack of blood to fill the vessels, and no deficiency of force to propel it; but from the insufficiency of the aortic valves, and the consequent reflux of blood into the ventricle, the prolonged swell which

*For the characteristics of obstructive pulmonary murmur, see ante, pp. 52. For the characteristics of obstructive tricuspid murmur, see ante, p. 56. For the distinctive characters of aortic regurgitant murmur, see ante, pp. 54 and 103.

at each systole of the heart is naturally imparted to the blood in the vessels is not sustained; the successive waves of blood, therefore, are short and abrupt, and hence the pulse is jerking, and gives a sensation as if successive balls of blood were being shot suddenly under the finger. When regurgitation exists only in a slight degree, this character is not strongly marked, but so strong is the reflux when the valvular mischief is great, and so strong is the jerking to which it gives rise, that the motion occasioned by it may be seen even at the wrist, and may be felt in almost any part of the body.

Regurgitation through the mitral orifice is, perhaps, the most common form of valvular disease. It produces hypertrophy of the left ventricle and dilatation of the left auricle, and may lead to systolic auricular impulse at the second intercostal space, by admitting of the transmission of the impulse from the ventricle. Further, when excessive, it may cause a vibration, or thrill, or purring tremor, which will be perceptible on the chest walls in the region of the heart, but which being occasioned by a backward instead of an onward current of blood, is not transmitted to any extent along the aorta or great vessels. When the disease of the mitral valve is of such a nature as to cause obstruction to the flow of blood into the ventricle, as well as to admit of regurgitation from the ventricle, the left auricle usually becomes hypertrophied as well as dilated, and then pre-systolic auricular impulse is sometimes perceptible at the second left intercostal space, occasioned by the systole of the auricle. Mitral regurgitation primarily interferes with the circulation through the lungs, and produces cough, and dyspnoea, and other symptoms of pulmonary congestion. It is in these cases especially that the outpouring of blood into the lungs, constituting pulmonary apoplexy, is most commonly observed.

The pulse is quite characteristic of the disease. It is not the small pulse of aortic obstruction, nor the jerking pulse of aortic regurgitation, but it is irregular in rhythm, and unequal in force and fulness, in consequence of the constant variation in the quantity of blood which at each contraction of the ventricle regurgitates or makes its way back through the imperfect valves into the left auricle.

Regurgitation through the pulmonary orifice is very rare, so that the effects produced by it have scarcely been verified by clinical observation. Theoretically, however, the small and constantly varying

* For the distinctive characters of regurgitant mitral murmur, see ante, pp. 52-3, and 102.

+ For the distinctive characters of regurgitant pulmonary murmur, see ante, p. 55.

quantity of blood which reaches the lungs at each systole of the ventricle should occasion dyspnoea, whilst as the right ventricle would become hypertrophied and probably dilated, regurgitation through the tricuspid orifice would after a time ensue, and congestion of the systemic and cerebral capillary circulation would take place, producing somnolence, headache, and dropsy. The mischief being on the right side of the heart, the radial pulse would not be materially affected.

Regurgitation through the tricuspid orifice as a result of disease of the tricuspid valve is of rare occurrence, but it is not uncommon as a consequence of dilatation of the right ventricle, in many of which latter cases it is unattended by murmur.* When it occurs, the right ventricle becomes hypertrophied, the right auricle dilated, the venæ cavæ distended, and there is a strong tendency to congestion of the systemic and cerebral capillary circulation. Not unfrequently the larger veins are so much distended that their valves become incompetent to prevent the reflux of blood, and then venous pulsation is visible in the neck, and venous thrill may be perceptible to the touch; but if the regurgitation be slight, or if the right ventricle be very weak, venous pulsation may not occur, and venous thrill will almost certainly be absent. The pulmonary circulation remains unobstructed, and the radial pulse is not materially affected, but somnolence, headache, and dropsy are more constant and distressing than in any other form of valvular disease except obstruction of the tricuspid orifice.

It will be observed that the symptoms which result from valvular disease are mainly dependent on one circumstance, viz., the impediment produced in the pulmonic and systemic capillary circulation. So long as there is no serious obstacle to the onward flow of blood through the heart, and no regurgitation of blood through the mitral and tricuspid valves, producing engorgement of the lungs and congestion of the systemic capillaries, no urgent or distressing symptoms arise. Hence it is that aortic and pulmonary obstruction, and aortic and pulmonary regurgitation, are less rapidly productive of distress than the same forms of disease at the mitral or the tricuspid orifice, and hence also it is that the existence of hypertrophy and dilatation of the various chambers of the heart-a circumstance which in certain forms of valvular disease has been shown to exercise an important influence in producing reflux of blood through the mitral and tricuspid valves-is found to have a marked effect on the progress and duration of valvular disease. Each form of lesion runs its own special course, and in its early stages For the distinctive characters of regurgitant tricuspid murmur, see ante, p. 53.

gives rise more or less to its own special train of symptoms, the distinctive features of which are referable principally to the greater or less degrees of pulmonic or systemic capillary congestion. But in their more advanced stages all forms of valvular mischief result in the production of a certain amount of capillary engorgement, and, therefore, have many symptoms in common. Those which more prominently attract attention are, oppression at the chest, breathlessness, and speedy exhaustion on exertion, a general sense of lassitude, headache, restless and disturbed sleep, with frequent starting, and frightful dreams, cough, palpitation, dropsy, and occasional pain in the region of the heart, sometimes amounting to severe angina. The rapidity with which cough ensues is mainly dependent on the tendency to pulmonary engorgement, and varies, therefore, with the amount of mitral obstruction or regurgitation; whereas the rapidity with which headache, restlessness, disturbed sleep, and dropsy supervene, is proportioned to the amount of systemic capillary congestion, and varies, therefore, with the extent of tricuspid obstruction, or tricuspid regurgitation. In the more advanced stages of all forms of valvular disease, but especially when there is extensive tricuspid regurgitation, the kidneys and other internal organs are apt to become gorged with blood, and an albuminous condition of urine may result.

As the symptoms above described may arise from either obstructive or regurgitant disease of a single valve, so they may be produced even more speedily by a combination of obstructive and regurgitant valvular disease. It matters little whether the obstruction and regurgitation result from disease of a single valve, or from obstructive disease of one valve, and regurgitant disease of another. In either case the impediment to the cardiac and the capillary circulation is necessarily great, and the resulting mischief is rapidly induced. In these cases murmurs are audible, referable both to obstruction and regurgitation; in short, there are double murmurs, the one due to the eddying of the onward current of blood, the other to regurgitation through an ill-closed, patulous orifice. These murmurs under ordinary circumstances correspond very closely with the same murmurs when occurring singly. Thus, the position and character of a systolic mitral murmur are usually the same whether the murmur exists alone, or is followed by the murmur of mitral obstruction. But in some instances of double murmurs the systolic murmur is so prolonged as to mask and render • inaudible the diastolic murmur which follows; in others, in which two