SECTION VI.-SUCCUSSION.

It has been seen that the succussion of certain contents of the chest, produced by the heart's impulse, and by the act of coughing, may give rise to physical phenomena of diagnostic import. And it was known to Hippocrates that if the chests of certain patients, labouring under thoracic diseases, be shaken, a "sound may be heard on the affected side." Hippocrates, however, erroneously supposed empyema to be the disease giving rise to this sound: his pathology was defective, but his observation correct and the phenomenon retains to the present day the name of Hippocratic (or thoracic) succussion-sound.

The succussion necessary for the production and detection of this phenomenon may be performed by pushing the patient's trunk abruptly (but with gentleness) forwards and backwards, while the observer's ear is applied to the chest; or the patient may himself move his chest once or twice in the manner indicated. The sound resembles closely that perceived on shaking a decanter, partly filled with water, close to the ear. Like that, it is a gurgling, splashing noise, the precise tone of which varies with the density of the fluid, and the proportional quantities of fluid and of air present. It differs in point of intensity according to the suddenness and force of succussion; but may be so easily produced as to be detected on the least movement of the patient, or during coughing. It may be audible at a distance from the chest, and be both heard and felt by the patient himself; and is, or is not, accompanied with metallic tinkling. Its duration varies greatly, -it may last for years, though this is very rare: in such chronic cases it is perceived by the patient, as he walks down stairs, rides on horseback, &c. It is not invariably a persistent condition when once developed; within twenty-four hours it may be present and cease to be producible, to recur again within a short period.

Produced by abrupt collision of air and liquid in an echoing space of large dimensions, the sound under consideration may be detected in hydro-pneumothorax, with or without bronchial fistula, and is occasionally to be heard in tuberculous excavations of unusually great size. Commonly audible over the general surface of the affected side, it may be limited to the anterior regions. The sign is, however, by no means always to be dis

*Louis, Phthisie, éd. 2, p. 412. Paris, 1843.

covered in hydro-pneumothorax: and one reason of its absence, thickness, and proportional excess of purulent fluid, was mentioned by Hippocrates:* it is certainly true that the thinner the liquid, the more readily is the sound produced.

SECTION VII.-DETERMINATION OF THE SITUATION OF SURROUNDING PARTS AND ORGANS.

The object of attempting to determine the situation of other parts than the lungs themselves, when the diseases of these organs are the subject of investigation, is, as might be anticipated, to infer from any change in that situation the existence of some pulmonary affection capable of producing it. Experience has shown that such displacements, so produced, do occur: and farther, that when present they are among the most conclusive (as they often are the most readily ascertained) signs of the pulmonary affection with which they are habitually associated.

The organs and parts liable to undergo displacement in consequence of pulmonary disease are-The Heart, the Mediastinum, the Diaphragm, the Liver, the Spleen, and the Stomach. The existence of displacement of these parts and organs is determined by means of various other methods of physical diagnosis, by inspection, by application of the hand, by percussion, and by auscultation; very rarely by mensuration.

The Heart may be removed from its normal position by(a) Detrusion, (b) Elevation, and (c) Procidentia.

(a) Lateral detrusion, for obvious reasons more readily detected when occurring towards the right side, is there commonly associated with slight procidentia; on the left, with some degree of detrusion, backwards and upwards. The progress of the displacement to the right side is usually gradual from its commencement till it has attained its greatest amount, when the organ pulsates between the fifth and seventh ribs to the right of the sternum. On the left it may be pushed almost under the axilla, its point being at the same time raised the width of an intercostal space, or thereabouts, and carried backwards towards the scapula.

Pleuritic effusion and hydro-pneumothorax are the affections which drive the heart sidewards to the maximum amount; simple pneumothorax is a rare cause; and hydrothorax, being

* Laennec, by Forbes, Amer. edit. p. 541.

generally double, does not displace the heart in this precise manner. Intra-thoracic tumours and aneurisms, variously placed, sometimes produce this effect; and hypertrophy, as well as emphysema, of either lung, are among its occasional causes. Besides, the heart may be drawn, as well as pushed sidewards, -a mode of displacement that occurs in some cases of rapid absorption of pleuritic effusion, of consolidation with marked contraction of the substance of either (but especially the right) lung, of pure atrophy (without distention of the air-cells) and also of great diminution of bulk from tuberculous disease* of the same organ. The practical interest of this matter is connected almost solely with pleurisy.

The heart can scarcely be pushed forward by any lung-affection, except emphysema; and various more prominent conditions (such as the formation of a thick stratum of lung in front of the organ) tend to mask this displacement. Intra-thoracic tumours and aortic aneurisms lying behind the heart, push it forwards, and, especially in the latter disease, give rise to very peculiar signs.

(b) Elevation of the heart above its natural level, a displacement of very rare occurrence as a consequence of pulmonary disease (though sufficiently common in cases of abdominal tumour and ascites,) is sometimes seen as an effect of diminished bulk of the apex of the lung. Such diminution only occurs in tuberculous disease, and is produced by atrophy of the lungsubstance, closure of air-cells, and contraction of exudationmatter, both interstitial and pleural. Dr. Stokes has known the organ pulsate under the second rib; I have never observed the apex higher than the fourth rib and third interspace.

(c) In procidentia of the heart the organ is below its natural level, and carried somewhat towards the median line; the impulse is then much more decided at the epigastrium (especially between the ensiform cartilage and left false ribs) than in the cardiac region. The common pulmonary cause of this displace

* I have twice, at the Consumption and University College Hospitals, seen the heart permanently beating in the right thorax, where no pleuritic effusions on either side had ever existed, as far as could be made out by present signs or past history, where the liver and spleen lay in their natural positions, and where great tuberculous excavation and destruction on the right side seemed to have drawn the heart in that direction, aided by perhaps the detruding influence of hypertrophy of the left lung.

I have known the heart permanently raised an intercostal space by splenic enlargement. Case of Dujardin, U. C. H. Males, vol. v. p. 192. June, 1850.

ment is double emphysema, of which it furnishes one of the most characteristic signs. It rarely exists to an appreciable extent in double bronchitis, if there be no emphysema; neither does double hydrothorax commonly induce it. The advance of tumours in certain situations may of course conceivably carry the heart downwards, but clinically this influence is rare.

The Mediastinum, at its lower part, is of course carried to the right or left by such morbid states of the lungs or pleura as produce lateral displacement of the heart. Superiorly, above the third rib, the mediastinum may be encroached upon by the lung (without any displacement of the heart,) and sometimes pushed more or less to the opposite side. Emphysema of either upper lobe will produce this effect, and if both organs are implicated, the mediastinum may be, as it were, obliterated by its pleural borders being brought into close juxtaposition: the percussion-sound will of course be unnaturally clear. Tumour connected with the upper part of the lung, circumscribed emphysema, tuberculous accumulation in the pleura, and acute hepatization, may cause encroachment on the mediastinum, with dull percussion-sound; tuberculization of the lung itself never produces this effect, the disease tending to diminish the bulk of the organ-hence occasionally a valuable aid in diagnosis. It is unnecessary almost to add that mediastinal tumours alter the relationships of the mediastinum; and that diseases of the great vessels, and of the heart likewise, deeply affect them.

The Diaphragm.—(a) In the normal state, the upper edge of the arch of the diaphragm, reaches, in the adult, the level of the fourth interspace on the right side, that of the fifth rib on the left, while the central tendon lies a little lower than this. In children the entire diaphragm rises somewhat less within the thorax. Full eating, and flatulent distention of the abdomen, temporarily raise it somewhat; and the habit of tight-lacing slightly depresses it.

The position of the right wing is ascertainable by percussion of the liver anteriorly; where the sound becomes clear on forcible percussion, carried from below upwards, lies the upper border of the liver, and (by inference) the convexity of the arch of the diaphragm. The cessation of vocal fremitus, where the liver is uncovered by lung, will corroborate the results of percussion, and supply a measure of the depth of liver covered by lung. The main guide to the position of the left wing will then be the fact that in health it always lies a little lower than its fel

low; while the position of the heart's apex and the special resonance of the stomach will afford corroborative evidence. It has, besides, been shown by Edwin Harrison, that the exact situation of the vault of the diaphragm may, in many cases, be rapidly determined by inspection and application of the hand. The mode of proceeding varies according to the shape of the thorax, which is, with reference to this investigation, of two kinds:-1. If the width of the chest be greater just above, than precisely on, the level of a line drawn transversely across from the lower part of the ensiform cartilage,-in other words, if a slight lateral depression correspond pretty accurately to that level-a very simple method is described by this observer for discovering the position of the upper edge of the diaphragm. Let the hand be passed from below upwards along the side of the chest (its inner edge being kept closely to the surface and the palm somewhat everted,) and that inner edge will sink into a narrow sulcus situated somewhat higher up than the lateral bulging just referred to. This sulcus, which may not be on the same level on both sides, indicates the precise height of, and corresponds to, the vault of the diaphragm. 2. If the width of the chest be less immediately above, than on the level of, the ensiform cartilage, this rule will not apply: however, the position of the left half of the septum may then be detected by the beat of the apex of the heart; and the right half is at least not lower than its fellow. In the main these guides are correct; but exceptions occur. Thus age, by enlarging the bulk of the lung through distended atrophy, or by diminishing that bulk through simple atrophy without distention, changes the position of the wings of the diaphragm, without affecting that of Harrison's sulcus. The sulcus is impressed on the side in youth, and remains unaltered in age. So, too, I have found that, where prolonged tight-lacing had driven the liver and diaphragm downwards, the sulcus had, for the same reason, ceased to correspond with the upper part of the arch.

(b) In disease. The wings of the diaphragm may be both raised; both depressed; or one only may be depressed or raised, its fellow remaining in statu quo; or one may be raised and the other depressed; or the central tendon may be specially depressed.

In order to determine with precision the nature and amount of disease affecting these changes, I have been in the habit for some time of noting the position in the dead body of both wings