There is an additional circumstance connected with the effect of posture in phthisis which is entitled to consideration. In health, the difference of rapidity of pulse produced by a change from the sitting to the recumbent position, is only about half as much as that produced by the change from standing to sitting; whereas, as far as I have observed in phthisis, the contrary rule appears to obtain. But, not to detain you longer with general statements, let me bring the facts under immediate observation. If any one of my audience in good health will volunteer, we will examine his pulse. The gentleman who has been kind enough to offer himself, I find, when sitting with the back supported, has a pulse of 74; but in the standing posture, allowing a little time for the effect of locomotion to pass off, it is 92. You will be struck by the close correspondence of this result with the table, which gives 13 as the average increase of beats produced by standing, on a pulse which is 80 when in the sitting posture.

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Let us contrast with this result the pulse of some of our patients. Here is one, M. A. G. Place your hand alternately under the right and the left shoulder-blade as she speaks. You observe how much more of vocal vibration is communicated to the hand on the right side than on the left. Listen to the breathing. You find each inspiration on the upper half of the right chest in front accompanied with two or three peculiar clicks. This is a characteristic sign of tubercular affection in the second stage. Try her pulse while sitting it is 124; on standing up, it is still 124.

Here is another patient, P. J., her pulse when sitting is 96; on standing it is 100, rising only 4 beats. Try

whether the state of chest is such as the rule which I am illustrating would require. There is dull percussion over the summit of each lung. On the left, under the acromial end of the clavicle, you find a bellows sound synchronous with the heart's contraction; at the sternal end a rubbing sound, produced probably by intercurrent pleurisy. Over the apex of the right lung you hear cavernous voice and respiration. There is some anæmia, and the pressure of tubercular lungs, under such circumstances, does sometimes, as in this patient, induce a bellows murmur, probably by superadding a disturbing cause to that induced by impoverishment of blood on the even current of the circulation. Supposing a person in health to have a pulse of 96, it should rise about 18 beats on standing; if anæmia were present the change should be still greater; but in the case before you the difference, you observe, is only 4 beats.

Let us examine one or two men, remembering that in males the healthy difference produced by change of posture is greater than in women. In this man, W. H., you may hear gurgling at the apex of the right lung when he coughs, proving conclusively the presence of vomica. In making percussion, I think you will be conscious of remarkable diminution of the natural elasticity. In placing my hand on the chest as he speaks, I have an impression that the vocal vibration is less felt than on the comparatively healthy side. If so, it is an exception to the general rule, which would lead you to expect increased vibration through tubercular lung; and this exception would be explained if, as I suspect, the tubercular deposition is in this case unusually diffused, and the bronchial tubes are extensively

obliterated. This patient's pulse is 100 when standing, and 96 when sitting; but the difference on lying down, when it sinks to 88, is remarkable, and in accordance with the rule which I have offered.

Look at one more patient, D. H. I may tell you that his spirometer number is very low, but you see from his general aspect, his long eyelashes, his gums margined in a way I may more fully describe to you in some future lecture, what you may expect. Under the left clavicle you hear the clicking rhonchus of softened tubercle. His pulse, when sitting, is 92; when standing, 96.

Examine, by way of contrast, the pulse of T. C. : when standing, it is 80; when sitting, even without supporting the back, it soon goes down to 73. The reason is clear to you. This is a patient whom you have formerly examined, and in whom you have detected cardiac disease and pleuritic contraction, but no phthisis.

These instances, taken as it were at random, may suffice to illustrate an obvious and interesting symptom of the disease. The explanation is not so easy. Is it that the heart, accustomed to a continuous cause of irritation, is less influenced by the trivial excitement which changes of posture might otherwise induce? or is there atrophy of the muscular coat of the arteries, and consequently less variety in the degree of influence exercised by this structure on the centre of the circulation? There is one analogy which may suggest a particular line of inquiry, and which is furnished by the fact, particularly observed by Dr. Graves, that the pulse of persons affected with hypertrophy of the heart is

remarkably little influenced in its frequency by change of posture. Is the relative weight of the heart to the body generally greater in phthisis than in other diseases ? The late Dr. Clendinning investigated this question with much care, and determined it in the affirmative.

The book of post-mortem observations now before you supplies some materials towards the settlement of this question. It records the weights of the hearts of twenty-three men and of nine women. On adding the weights of the former, and dividing by twenty three, I get eight ounces and nine-tenths-on adding those of the latter, and dividing by nine, I obtain a result of eight ounces and a third; in both instances, above the average of the healthy heart, and yet many of these subjects were very much emaciated. Should further observations be in harmony with these calculations, there would be so far an analogy between the heart in phthisis and the heart in a state of slight hypertrophy. The fact that the pulse of women and children is less affected by change of posture than that of males and adults, affords countenance to the idea that the condition of the muscular coat has an influence in the phenomenon so characteristic of phthisis; while the remarkably slight effect produced by emotion on the frequency of the phthisical pulse lends support to the hypothesis, which would assign as an explanation the pre-occupation of the heart by other sources of irritation. The three particulars at which we have glanced may possibly combine their influence, or it may be that the cause has yet to be sought, but of the fact I do not think any substantial doubt can be entertained. If you compare

the pulse of a consumptive patient on different days, you will often find that its variations in frequency are more considerable than can be readily explained; but on the days when the pulse is least frequent, you will usually find the difference produced by change of posture to be greatest. Whatever discrepancies may be remarked, you will commonly perceive a want of harmony with the rule which obtains in health, and often rendered more apparent on taking the mean of several observations. When tubercular deposit exists in the lungs, it is doubtful whether the pulse, under any improvement of general health, ever regains its sensitiveness to change of posture; but when the tubercular element has not become localized, I have reason to think that the pulse, if the constitutional condition be ameliorated, may to a considerable extent recover the disposition to vary, from the cause which we are now considering. The hints which I have given in this lecture may encourage you to expect considerable aid in diagnosis, and prognosis, from a careful examination of the pulse. In this, as in most things, there are two extremes to be avoided. You know that the Chinese physicians were long accustomed to form their diagnosis from the pulse alone, and often without even seeing the. countenance of their patients.

Dr. Rucco, in a voluminous work on the subject of the pulse, gives instances in which he predicted the sex of the fœtus in utero from the maternal pulse. "We examined," he says, "the pulse of the lady of the Signor Raffaelli, of Naples, and after repeated observa

* Introduction to the Science of the Pulse. London, 1827, vol. ii. p. 248—421.