whispering this is avoided, and the decisive, though feeble cavernous sounds, are allowed a hearing. The feeble whispering voice agitates the cavity air only, the strong voice throws the solid parts also into strong vibration, and suggests merely solid conduction.

AMPHORIC VOICE, OR AMPHORILOQUY OF CAVITIES.-The cavernous direct pectoriloquy, or thoracic voice of the third stage of phthisis, occasionally is found to partake of a hollow vessel, pitcher, or amphoric tone. I have heard this kind of cavernous voice more than a dozen times. It is usually associated with amphoric respiration, or respiration sounds having the same resounding or thin metal sheet ringing tone. The voice is not strong; it is a diffused chamber-like sound. The diffusion, however, is much less considerable than the diffusion of the amphoric voice of perforation. The tone of the amphorism of cavities is much the same as that of the pleural cavity, although less marked in general. The amphoric tone, I must however say, has been as highly, as strongly, and completely marked in mere cavity cases as in examples of pneumothorax depending upon perforation. This cavity amphoric voice, like the amphoric respiration sounds of cavities, has been heard by me at the upper part of the chest. It has a large range from the clavicle down to the third rib, and is heard usually behind as well as in front. The cavity which emits this kind of voice is always large. I believe it to have thin, hard, and smooth walls, to contain little if any liquid. Finger dulness, or something near it, is always present, and the true cracked-pot sound is to be elicited in about fifty per cent. of cases of this sign.

QUASI EGOPHONY OF CAVITIES. I have, in some few examples of phthisis, heard a quasi ægophony, altogether independent of effusion into the cavity of the pleura. It has only a moderate amount of tube squeaking character, but there is much vibration or trembling with it, and it is loud and like true ægophony near the ear of the auscultator. It has occurred in the case of very large cavities only in my experience. The usual seat has been the upper part, mammary region, and towards the axillæ. I have been assured of the existence of cavities by the presence of whispering pectoriloquy of the usual character, prior to the advent of this quasi ægophony, and of hollow cavernous respiration sounds. I met with an example of this quasi ægophony in a gentleman who died of phthisis in the third stage a year ago. The voice trembled exceedingly. When this form of cavernous voice occurs, it is obvious that the mechanism of

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the bronchial openings and of the thin walls of the cavity are promotive of more than usual vibration.

ÆGOPHONY. This is one of the most remarkable of the remarkable physical signs observed in the third stage of phthisis. It is heard very rarely, and only when effusion has taken place into the pleura. Some physicians, it is true, believe it to be occasionally produced when consolidation only is present. This necessary effusion is in a very large majority of examples of this sign, sero-purulent, and is the result of pleurisy. In some few examples I have known the liquid to be only serous, but in these examples the sign has never arrived at its most complete state of development. The character of the effusion has been ascertained after death. The sound of the ægophonic voice resembles the bleating of a sheep, or of a goat, and it is from this latter resemblance that it is indeed designated Ai, aiyòs, capra. It possesses the trembling character of the bleating animal. A squeaking character enters into its composition, and the voice certainly resembles in some measure the squeaking of Punchinello. It is as if the voice, after being formed, were transmitted through a narrow tube and through a solid body in a state of tremor or trembling.

This form of voice is difficult of description, but when once heard it is not likely to be mistaken for another sound. The chief seat of this voice is the middle of the chest, and a little below it; far most frequently at the posterior aspect. Its most frequent point of development is the angle of the scapula, over the scapular region, and extending to the spinal column. It is very seldom heard above the spine of the scapula, and is developed more externally than the outer edge of the scapula. In few instances has it been heard in front in phthisis, but in one or two cases I have heard it at the mammary region. The adhesions of phthisis are likely to prevent the frequent discovery of this sign high up in the thorax. The voice is loud, and it seems superficial.

The anatomical and pathological conditions when this sign is present are these: effusion, mostly sero-purulent, occasionally serous only; a collapsed and somewhat solidified and compressed condition of the lung; immersion of part of the lung in the liquid, pressure of the bronchial tubes by the liquid sufficient to narrow them, but not totally to occlude them; laryngeal voice of some force.

In

The ægophonic voice is essentially a temporary one. the case of some patients, it may have one period only, or it may have two. That is to say, it may appear, and after

some days disappear, never to return; or it may appear, last a few days, disappear, and then, after a week or two, it may return, but to disappear finally after some days. Egophony of phthisis in the third stage not uncommonly remains till the time of death. When it has only one period, the duration is generally greater than when it is to return. When of a single period only, it is heard as soon as the effusion has reached as high as the level of the angle of the scapula. As long as the liquid reaches no higher, and is not materially reduced, the characteristic voice remains. When the effusion notably reduces, the voice with its singular characteristics disappears. When the voice has a second period, the effusion proceeds to a great extent, its level rising as high in some cases as the third or even the second rib. As soon as the liquid level has attained the level of the fifth rib in front, the characteristic voice is lost, but as the liquid abates by absorption, and the upper part of the lung and the bronchial passages are liberated from compression, the voice again returns, but generally only for a few days, for the process of absorption proceeding, liberates the lung and bronchial tubes altogether from compression, and puts a stop to that immersion of the lung which is essential to the development of the true and perfect ægophonic sign.

The ægophony of phthisis in the third stage is generally associated with cavernous respiration, feeble and more obscure, it is true, than before the effusion, or after its total absorption. There is usually some cavernous voice at the apex. The percussion sound is absolutely dull from the base upward to the seat of the ægophony; respiratory sounds are absent or faint, or as if distant. There is a total absence of any kind of voice for the most part at the very base of the lung. The semi-diameter of the chest is increased; the ribs move little, and the aspect of the side is more rounded than usual, and the interspaces are fuller. When ægophony disappears, this may be due to increase as well as decrease of the effusion; the travelling of dulness and of silence, so to speak, upwards marks increase; the travelling down of these signs, and their mitigation or reduction, indicates the decrease or absorption of the liquid.

Ægophony almost invariably takes place upon the side of the chest which is the seat of cavities; but though I have not seen an instance of it, there appears no reason why it should not be heard on the opposite side, where no cavity exists, and yet owe its presence to pulmonary tubercle disease. The ægophony of phthisis is more frequently found in the

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third stage of the disease than in any other, but it is occasionally heard in the first and in the second. In the fourth stage, though effusion is present in a very large proportion of cases, I have not heard ægophony in any one instance, the presence of air in the pleura counteracting the influence of liquid, quoad ægophony. I have, partly on these grounds, preferred describing this sign in connection with the third stage of the disease.

The mechanism of ægophony has excited much attention, and little approach to unanimity is to be found in respect of it amongst physicians. It appears to me to be unnecessary to detail the various views of auscultators on this sign. The explanation which I have to offer is this, and I believe it to be at once consistent with the laws of sound, and with the pathological conditions under which it is found.

In the first place, the force of the voice when it has reached the bronchial tubes at the mid-chest, is unduly augmented. The diffusion of the sonorous undulations through the lung is partially prevented by the solidification always present; the bronchial tubes are more freely brought into vibration, and this adds to the sound. The constricted punchinello squeaking character is imparted by the compression, partial it is true, of the bronchial tubes, particularly at their posterior and membranous part. The liquid compresses the tube, narrows its calibre, and so imparts the characteristic squeaking sound. The compression is, however, of so feeble a character that the unduly strong voice is sufficient to throw the parts into undue vibrations, and the articulated sounds are propagated in a trembling manner.

The trembling begun in the bronchial tubes is communicated to the solidified lung lying loosely immersed, in part at least, in the liquid. The trembling is continued, favoured by the little resistance of the liquid, throughout the middle of the lung and thence to the liquid itself, and lastly to the thoracic walls. There is just that amount of resistance from the liquid to recoil the lung after its excursion, so to speak, under the force of the voice. The voice force and the liquid compression force are so nearly equal, that a system of vibrations is established. Less compression upon the air tubes and less voice would not suffice to freely vibrate the tubes or the lungs, and more compression would be fatal to vibration of these parts. This may be imitated; a flexible tube of indiarubber compressed at a part very feebly and a feeble voice will give no squeaking sound; a little more pressure and a little more force of voice will impart the

squeaking character. Press more firmly, so as nearly to obliterate the tube, and the squeaking character will be lost. So we find in respect of ægophony, a little liquid developes the sign, and a great deal removes it.

REDUCED VOICE AT THE BASE. In a very large proportion of examples of phthisis with cavities at the apex, the thoracic voice at the base, as has been already incidentally stated, is much impaired. This holds when the base of the lung is condensed and the bronchial communication is reduced. The comparative weakness of the voice of the diseased base is well made out by using the differential stethoscope bilaterally and at the same moment. In many examples, no voice whatever is then heard on the diseased side. There is no doubt that the reduction of the voice is due to the reduction of air-communication. I have listened for the sounds of a watch and a tuning fork proceeding through consolidated lung out of the body, and have found that their intensity was increased when a hole, the calibre of a large bronchus, was made through it, and the stethoscope placed over the aperture. The difference was very great when the flexible or differential instrument was employed; less so when the wooden stethoscope was in use.

The total abolition of the voice at the base in the third stage of phthisis is uncommon. It is found in those rare examples only in which effusion to a large amount has taken place in the pleura. Egophony at the angle of the scapula and finger dulness on percussion mark these cases.

Bronchial Sounds. Constrictive Sounds.

Moist and liquid Bronchial Sounds. Laryngeal and tracheal Sounds: Tracheal Ticking and laryngeal Constriction Sounds. -Pneumonic Crepitation.

BRONCHIAL Sounds, in the third or cavity stage of phthsis, are extremely common. They are for the most part the result of the tubercular disease, and they increase with the progress of the excavation. They frequently contribute to mask the proper signs of cavities. With care, however, both classes of signs may be discovered. The bronchial sounds may be dry