Of the cases included in Q 1, with marked dulness on one side, it is to be remarked that superadded sound, when it is of the interrupted kind, generally indicates that the change in density is due to Interstitial deposit : its fineness or coarseness being determined by the size of the tubes or spaces in which it is formed, and the character of the exudation by which it is caused. When dulness is marked, and the sound fine, it may be pretty confidently assumed that the condition is one of hepatization, either with or without tubercle ; be cause miliary tubercles could not account for the dulness, when existing only to such an extent as to produce irritation and exudation in the small tubes and vesicles. When the sound is coarser, and consequently formed in the larger tubes, or in a number of small cavities, the general symptoms and his tory must determine whether we have to do with the second stage of pneu monia, or with phthisis • the latter being the ordinary, the former a very unusual cause. When large bubbling sounds are heard, we are sure that considerable hollow spaces exist, which can only be the result of tubercular cavities, or of the much rarer inflammatory disorganization of lung tissue, which is always accompanied by fetor of the breath and sputa.
The continuous sounds are seldom heard with marked dulness. Friction is occasionally met with under the clavicle when the dulness is caused by pleu risy, but is more commonly absent. Sonorous sound, as indicating a minor degree of irritation of bronchial tubes, not extending to their minute ramifi cations, might be taken as confirmatory evidence that the dulness was caused by a tumor.
When resonance is excessive on one side (f 2), the only sound which can be of much value in the clavicular region is the sonorous ; by its presence the movement of the air in the larger tubes becomes appreciable, when, in conse quence of the interposition of emphysematous lung, In which the air is all but stagnant, no breath-sound at all would be heard on the resonant side. Most sounds, too, may sometimes be detected on the resonant side, when the bron chitis is severe, but these rather belong to the next section.
In 3 we find the very important contrast between partial consolidation, which is generally tubercular, and partial emphysema. The very fine sound of irritation of the smallest tubes which sometimes accompanies raillery tu bercle, comes very close upon the crepitation of pneumonia ; sometimes, too, the tubercular deposit produces a real pneumonia of slight extent, with genuine crepitation; such cases must be regarded from a general point of view, which includes all the signs and symptoms, or else an error in diagnosis very likely to be made; an while admitting.the high probability that the consolidation has a tubercular origin, we must still not forget the possibility of simple pneumonia.
The clicking and squeaking sounds of softening tubercle are very decisive when the difference in percussion resonance on the two sides is not very great; and equally valuable is the sonorous sound of bronchitis with emphysema ; the one heard on the duller, and the other on the more resonant side. But some times the several explosions or bubbles are more numerous, and assume the form of moist sounds, and these, as well as the sonorous, may be heard either on the duller or the more resonant aide. It may happen, too, that the stu
dent, while recognizing a difference, is mistaken in regard to the relative re sonance of the percussion stroke, and his intepretation of the cause of the sounds is utterly wrong; they mean, perhaps, only the presence of local bron chitis, but they do not show why it exists. Error in such cases is best guarded at by a careful consideration of the indications derived from the rest Ortihne chest; if no moist sounds be heard elsewhere, or if no evidence of em physema be obtained from other parts of the same lung, there will be a strong presumption in favor of the difference in percussion sound being due to tubercle ; their general distribution must be considered subsequently. It need only be added that the presence of any obstruction in the bronchial tubes, while giving rise to superadded sound, is very apt to interfere with the breath-sound and deprive us of the indications of consolidation which it might afford ; and this was mentioned, in the former chapter, as an important means of coming to a correct judgment in the matter.
Creaking and crumpling sounds are less frequently met with in the cases referred to in this section than in the following one : but as they decidedly belong to those in which some form of consolidation has occurred, they at least serve to determine the question of percussion dulness, and to give great preponderance to an hypotheais of tubercle as its local cause.
In 4 we meet with the cases most important to the physician, most puz zling to the learner—the first stages of phthisis; with the exception of a few instances in which tubercular softening.has occurred in the lower lobes, there are none connected with auscultation in which it is so difficult to come to decided opinion. It is true that the patient cannot know whether we be right or wrong, and that it is a safe course to give a rather unfavorable prognosis in all cases of doubt : it is true that this course is pursued by many of the most popular and most successful practitioners; but it is also true that this is the course of quackery and imposture, and I believe that no earnest student will be satisfied with it, and that no right-minded physician feels quite com fortable in practising the little deception which such a method implies.
Here it must be admitted that superadded sounds are sometimes extremely valuable, because when we cannot find anything wrong elsewhere, they suggest the existence of local disease, and that local disease may be tubercular. The crumpling sound, when heard, is, like the wavy or jerkmg breath-sound, that which is most constantly associated with tubercular deposit. Creaking only proves the previous existence of local pleurisy, which very frequently is set up by, and, perhaps, sometimes ends in, tubercle. The fine moist sounds and the sonorous eounds referring only to bronchial irritation, derive their whole value from being the exponents of local action, whether they be heard at the apex only, from the first, or linger there when they have ceased to be heard eWwhere.