who possesses it, and feels the duties which belong to one intrusted with human life. But the indirect benefits derived by society from any method which gives accuracy to medicine, are neither few nor unimportant. Formerly, for example, when physicians had no certain information to give us concerning the forms and stages of consumption, every species of trial was enjoined and carried into effect, with regard to this disease. One man mewed his patients for months in cow-houses-a second shut his up in well-stoved rooms—a third exposed his to the open heavens under every variety of atmosphere, and stuffed them with beef-steaks. Tar-vapour and tar-water were the specifics with one class of practitioners, caustic washes with another. And all, amidst their diversity of earlier practice, agreed on removing the despairing sufferer, too often quite uselessly, to another climate. The errors of this empiricism were great aggravations of the natural course of the malady. There is a double death for one who parts to die; and though his days, under whatever management, may be but few and full of sorrow, the absence from friends, from home, and from his country, will scarcely alleviate the pangs of the last hour.

Auscultation implies a listening-the ear, especially if assisted by a small trumpet-shaped tube, can hear many sounds which arise from the healthy action of our internal organs. Thus, the beat of the heart may be heard, as also the rush of blood along the arteries. Thus, too, the ingress of air into the lungs is accompanied by a murmuring noise, which is very distinct in most healthy individuals and audible in all. In some parts of the pulmonary tissues, the sound is louder than in others; and we find that this is accounted for by the natural structure of such parts, for the air tubes are here larger. If the ear is accustomed to recognize the sound which attends the act of respiration in a healthy lung, it readily detects any deviations from it in the diseased lung. Then the sole question that remains to be determined is, the nature of the malady producing these deviations; and this is answered by the investigation of the diseased organ in those who have succumbed. In short, by the repeated examination of the act of breathing, we learn that certain sounds are heard only in a healthy structure; and that certain deviations from such sounds denote a change in such structure-which change is disease. Let us apply this general proposition to the investigation of pulmonary diseases, But in order to render ourselves intelligible, we must give a popular, and therefore imperfect, description of the intimate structure of the lungs.

The lungs may be looked on as a set of tubes, which ramify like the branches of a tree, and end in tiny bladders. Perhaps a bunch of grapes when the fruit is just appearing, and is small in

proportion

proportion to the stalk, will assist the imagination in figuring the lung. The minute bladders or air-cells are not, however, loose like each grape, but in apposition with each other like the cells of a honeycomb.

The trachea or windpipe, a tube about four inches long, and three quarters of an inch in diameter, is the stem from which all the branches are given off. Immediately after it has entered the chest it divides into two tubes, one of which goes to the right, the other to the left lung. That to the right sends off a branch to each of the three compartments or lobes of the lung of that side: while that to the left sends off but two, one to each of two lobes. These larger branches of the windpipe, called bronchi, are then subdivided into numberless gradually diminishing tubes, the least of which terminate in those bladders, or air-cells, or vesicles, which are in diameter not more than 16-100th parts of an inch. The whole of these tubes and cells are lined with a mucous membrane, similar to that on the inside of the cheek, on which innumerable minute blood-vessels are spread, for the purpose of being brought into contact with the air, which passes from the windpipe through the bronchi to these cells.

Of all parts of the lung the mucous membrane is the most liable to become diseased. It is essential to our hearing the healthy sound in breathing, termed the respiratory murmur, that the great air-tubes and their ramifications should be, not only pervious but lubricated-yet not in excess. If there is an excess of the natural moisture secreted by the mucous membrane, the air in passing through the bronchi will become entangled in the fluid, and form bubbles, which burst and crepitate during the act of breathing and so are readily heard. These Dr. Latham has called moist sounds.' If, on the other hand, there is a deficiency of fluid, then the sounds have been termed dry sounds;' of which Dr. Latham has made two varieties, a hoarser (rhonchus), a shriller (sibilus)-and from what is familiary known of the sound produced by blowing into tubes of greater or less calibre, it will readily be understood that the shriller noise proceeds from the smaller, and the hoarser from the larger ramifications of the bronchi. Of the moist sounds he has also made but two varieties, the large and the small crepitation. The large crepitation occurs in the larger bronchi, for here there is sufficient space for the formation of an ampler bubble; while the small crepitation arises in the minuter tubes, where the struggle between the passing air and entangling fluid is carried on in a more confined space. Thus, to a certain extent, the kind of sound denotes not only the excess of fluid, but the part of the lung in which that excess exists. Let us apply these facts to the investigation of diseases of the lining membrane of the lungs.

Of

Of those sounds which are not moist,' the hoarser or rhonchus is the most common and most variable. Its commonest cause is a tough piece of phlegm adhering to the sides of the larger bronchi, too solid to permit the air to pass into it, or do more than make it vibrate like the tongue of a Jew's harp. Persons in the most perfect health may have rhonchus, which an effort of coughing will remove. A more dangerous cause for the occurrence of this sound will be found in obstructions of the great airtubes, from tumours or ossifications, which narrow their calibre. Sibilus, or the shrill dry sound, cannot be regarded as so trifling a symptom as rhonchus. It is usually heard with the sound called the small crepitation, and there is in such cases an alternate predominance of either sound. The diminution or increase of the sibilus coincides with the diminution or increase of the inflammatory symptoms, and with the increase or diminution of the expectoration, so that there is little or no expectoration when we hear the sibilus, and much when these shrill sounds cease. The following examples will illustrate the importance of the foregoing remarks. Dr. Latham says

'There are cases of (what I suppose would be called) genuine asthma, that present some such symptoms as these dyspnoea, or rather an agony and fighting for breath; livid lips; cold and livid extremities; and a dry ineffectual cough, terminated and relieved, after an uncertain interval, by a copious puriform expectoration. Here, during the agony or paroxysm-(and unfortunately it often continues long enough to allow a very leisurely examination of the chest by the earsometimes many days, sometimes a week or two)-the sole auscultatory sign is a sibilus, pervading a larger or smaller portion of the lungs, according to the severity of the case. And, as the agony lessens, and the expectoration begins to appear, crepitation is found mingling itself with sibilus; and, when the agony has entirely ceased, and the expectoration become more copious and free, crepitation, and crepitation alone, is then heard in the same situations, and to the same extent, that sibilus, and sibilus alone, was heard before. I have witnessed instances of asthma in several individuals, and several attacks of asthma in the same individual, where the auscultatory signs have had as strict and definite a correspondence with the stages, progress, and prominent symptoms of the disease, as that which I have here described. Now, if absolute dryness can be ever safely predicated of the respiratory passages, and can be ever safely reckoned among the pathological ingredients of their diseases, and ever clearly notified by one express symptom, it is in spasmodic asthma, of which it seems the chief pathological ingredient during its first and often most protracted stage, and is clearly notified by a widely diffused sibilus. I am persuaded that the natural moisture of the respiratory passages is then really in defect, and that sibilus is really an index of the fact. Sibilus may then, if ever, be truly called a dry sound. But I am not sure that

the

the sibilus directly results from the mere condition of dryness; I doubt whether simple dryness alone would naturally produce it. In consequence of its dryness the mucous membrane may lose its elasticity, and become to a certain degree unyielding; or it may undergo wrinklings or puckerings at various spaces, or its general tumefaction may produce a narrowing of the smaller tubes, and thus present obstacles to the passage of air, and impart to it new vibrations; and hence the sibilus. But does sibilus ever occur in acute bronchial or vesicular inflammation? And does it ever so occur as to throw essential light upon morbid processes going on, and upon modes of treatment? Inflammation of the bronchial ramifications perhaps never exists without the natural secretion of their mucous surface being either diminished or increased, and, consequently, without the accompaniment of those sounds which indicate its defect or excess, i. e. without sibilus or crepitation. Sibilus is apt to occur at the beginning of such inflammation; and thus it corresponds with the pathological condition out of which it arises, the mucous membrane, when it is inflamed, becoming drier than ordinary before it yields a more abundant secretion. Sibilus, too, after it has arisen, is apt to be of short duration, seldom abiding long as the sole auscultatory symptom of such inflammation. And herein also it corresponds with the pathological condition from which it proceeds; for the dryness of the mucous surface generally soon gives place to moisture. Hence it happens that sibilus is so seldom met with in practice, except with some mixture of crepitation. The inflammation is, in truth, not submitted to our observation until the stage of dry sounds is passing, or has already passed, into the the stage of moist sounds. Nevertheless, there are cases in which sibilus is the sole and abiding symptom derived from auscultation, and a dryness of the air-passages the sole and abiding morbid condition. They are cases distinct from asthma-cases of genuine inflammation, and so remarkable as to require an especial notice. I have met with a frightful affection in children; but what its nature was I could never tell, until auscultation enabled me to unravel it. It commonly passes for inflammation of the lungs. But, when children have got well, they have got well so soon and so entirely, that I could never believe the disease to be pneumonia, although the symptoms seemed to indicate that it could be nothing else.

Last summer I went out of town to see a little boy, seven or eight years of age, whose life was very precious to his family. He was thought to be dying of inflammation of the lungs. I found him raised up in bed, supported by his nurse, and breathing with all his might. His skin was hot; his face flushed; and his chest heaved, and his nostrils quivered frightfully. There was no croupy sound. Whatever the disease was, it was all within the chest. I percussed the chest: it sounded well in every part. I listened: the air entered freely, and reached every cell and vesicle of the lungs; but there was not the least perception of the natural respiratory murmur : a shrill sibilus had taken place of it altogether. Wherever you applied your ear to the chest, you might fancy you heard the piping and screaming of a nest full of unfledged birds.

• But

'But what was this disease? Surely it was inflammation largely diffused over the mucous surface throughout the bronchial ramifications, but inflammation as yet only in its first stage; for the air, as it passed through them, did not mingle with a particle of fluid anywhere, and the sound it produced was a dry sibilus only. But how inflammation yet only in its first stage? The boy had been already ill four days. Still it might be inflammation in its first stage. The boy continued ill two days longer, with the same kind and the same degree of suffering; and then, under the influence of tartar emetic, the fever began gradually to subside, and the dyspnoca to abate. The sibilus gradually gave way to the healthy respiratory murmur, and he was well again without expectoration of any kind. The inflammation began and ended with the first stage; and, although it continued with great severity for a week, it never got beyond the first stage. This is an instance, which strikingly shows the value of auscultation in detecting at once the state of things, about which you might go on conjecturing and conjecturing for ever what it possibly might be, and not gain the least assurance what it actually was.

'In adults sometimes, but not so frequently as in children, I have met with the same evidences of acute inflammation widely diffused through the bronchial ramifications, and remaining in this its first stage for days and days together. In the mean time their mucous surface has still been dry throughout a great part of both lungs, and the ear has continued for days and days together to hear no other unnatural sound but a sibilus. Convalescence has taken place without expectoration, and the sibilus has given way, without the intervention of any moist sound, at once to the murmur of health. But such inflammation, after lingering long in the first stage, will sometimes pass beyond it; and the whole mucous surface that was previously dry will pour forth an enormous secretion, and the widely diffused sibilus will be changed into a widely diffused crepitation. Still the lungs are unhurt beyond the lining membrane of the air-passages, and the patient will get well, if he be not suffocated by the enormous expectoration. I am speaking of a disease which must be distinguished from asthma, according to the usual acceptation-a disease not habitual to the individual, and of which, perhaps, he has never suffered a previous attack. I am speaking of acute inflammation extending throughout the bronchial ramifications, and reaching, perhaps, the vesicular structure of the lungs, putting on a peculiar form, and affecting a peculiar course; but still of acute inflammation, as further evidenced by the remedies necessary for its relief.

During the last summer I saw a gentleman who had been, two days previously, seized rather suddenly with feverish symptoms, and with the most dreadful dyspnoea. His lips were blue; he was labouring for breath, and coughing with hard and ineffectual efforts to rid himself of something which seemed to tease the larynx, but no expectoration followed. Cupping on various parts of the chest (the state of vascular action required that blood should be drawn), and tartar emetic in frequent doses, were the remedies employed; but in the same state of agony he remained for a week,

propped