A positive diagnosis must rest on physical signs, together with more or less of the foregoing symptoms. The physical conditions which furnish the diagnostic signs are solidification of a small portion or of small portions of lung, usually at or near the apex, the presence of mucus in the small-sized bronchial tubes, and perhaps fibrinous exudation on the pleural surface within a circumscribed area corresponding to the solidified portion or portions of lung. The signs furnished by these conditions are slight dulness on percussion, a broncho-vesicular (formerly called rude or harsh) respiration, some increase of vocal resonance and of the whispered voice, subcrepitant râles, and perhaps a grazing friction murmur. It may be important to consider the physical signs of phthisis with some detail. Aside from their importance, a reason for this is that terms by which some signs are designated are not used in precisely the same sense by all medical writers.
A small phthisical affection gives rise to slight or moderate dulness on percussion. In order to appreciate this sign if the dulness be slight, attention should be paid to the pitch of the resonance as well as to the lessened intensity of resonance. The pitch is always raised. By attention to the latter character, in conjunction with the diminution of intensity, a degree of dulness may be sometimes appreciated which, without attention to the pitch, might not be determinable.13 In determining abnormal dulness in the infra-clavicular region on one side, the normal disparity between the two sides of the chest in this region must be taken into account. The resonance at the right summit, as compared with that of the left summit, is, normally, somewhat dull. Hence it is not as easy to make out an abnormal dulness at the right as at the left summit. If the relative abnormal dulness at the right summit be but slight, the question is whether there be more than a normal disparity. This question is rendered difficult by the fact that the degree of normal disparity varies somewhat in different healthy persons. In cases of doubt little reliance is to be placed on this sign alone, but it is to be taken in connection with auscultatory signs.
13 The author was the first to indicate the fact that dulness is always associated with elevation of pitch. Vide "Prize Essay on Variations of Pitch in the Sounds obtained by Percussion and Auscultation," Transactions of the American Medical Association, 1852.
With reference to the auscultatory signs in cases of phthisis, it is to be premised that often, owing to the importance of studying the sounds derived from a limited area and of localizing morbid conditions, the use of the stethoscope is indispensable. It is impossible to meet all the requirements of physical diagnosis by immediate auscultation. After an experience of more than a quarter of a century the writer would advise the binaural stethoscope in preference to any other. For the benefit of those who are not practically familiar with this instrument, it should be added that in order to appreciate its advantages, the instrument, in the first place, must be properly constructed, and, in the second place, some practice is necessary. A sound produced within the instrument is at first an obstacle, but it is speedily overcome by use.14
14 The dissatisfaction with the binaural stethoscope so often comes from defects in its construction that it seems proper to refer to Tiemann & Co., and to Ford & Co., of New York as reliable makers of this instrument.
A small tuberculous solidification is represented by a broncho-vesicular respiration. This sign was named and described by me in 1856. The name takes the place of the terms rudeness, harshness, and hardness—terms which are not only inadequate, but convey an erroneous idea. Quoting from another work, the characters of the broncho-vesicular respiration and its comprehensive signification are as follows: "The sign represents the different degrees of solidification of lung between an amount so slight as to occasion only the smallest appreciable modification of the respiratory sounds, and an amount so great as to approximate closely to the degree giving rise to bronchial or tubular respiration. In other words, all the gradations of respiratory modifications caused by incomplete or an inconsiderable solidification are embraced under the name broncho-vesicular. The gradations correspond to the amount of solidification; that is, they show the solidification to be either very slight, moderate, or nearly sufficient to be regarded as considerable or complete. The sign is therefore important as evidence, first, of the existence of solidification, and, second, of the degree of solidification. Analyzing this sign, the most distinctive feature is the combination of the vesicular and the tubular quality in the inspiratory sound. These two qualities may be combined in variable proportions. The pitch of the sound is raised in proportion as the tubular predominates over the vesicular quality. The expiratory sound is more or less prolonged, tubular in quality, and the pitch raised. The prolongation of this sound, its tubular quality, and the raised pitch are proportionate to the predominance of the tubular over the vesicular quality in the inspiratory sound. If the solidification be slight, the characters of the normal vesicular respiration predominate; that is, the inspiratory sound has but a small proportion of the tubular quality, and is but little raised in pitch, the expiratory sound being not much prolonged, its tubularity not marked, the pitch not high. If, on the other hand, the solidification be almost enough to give a bronchial respiration, the inspiratory sound has only a little vesicular quality, the tubular quality predominating, the pitch proportionately raised, and the expiratory sound is prolonged, high, and tubular, nearly to the same extent as in bronchial respiration. The less the solidification the more the characters of the normal vesicular respiration predominate over those of the bronchial respiration; and, per contra, the greater the solidification the more the characters of the bronchial predominate over those of the normal vesicular respiration."15 By means of the broncho-vesicular respiration a slight morbid solidification may be recognized in one of the infra-clavicular regions or over the scapula. Here, however, as with regard to percussion, an allowance is to made on the right side for a normal disparity. The respiratory sounds on the right side at the summit, as compared with those at the left, have normally the characters more or less marked of a broncho-vesicular respiration. These characters are more marked as the stethoscope is brought toward the sternum. Hence a small solidification of lung is more easily ascertained by auscultation at the left than at the right summit.
15 Vide Manual of Auscultation and Percussion, by the author; also, paper contained in the Transactions of the International Medical Congress, London, 1882. The broncho-vesicular respiration was called by Skoda indeterminate (unbestimmt), and this term is still used by German writers. These sounds are not indeterminate if the characters derived from pitch and quality be analytically studied; they are sounds intermediate between the normal respiratory murmur and bronchial respiration.
Not infrequently in cases of incipient phthisis the respiratory sounds at the summit on the affected side are so weakened that their characters cannot be studied. Weakness of the respiratory murmur in these cases becomes a diagnostic sign taken in connection with other signs.
A small tuberculous deposit may increase the vocal resonance. But, again, a normal disparity between the two sides must be allowed for. The normal vocal resonance is always greater on the right side. If, therefore, it be a question as to the existence of a small tuberculous affection at the right summit, it is to be decided whether the disparity be greater than normal. A small tuberculous deposit at the apex of the left lung, on the other hand, may not increase the resonance to an equality with that at the right summit.
Attention should be paid to the whispered voice, and, still again, the two sides show a normal disparity. The sound heard with the whispered voice, which may be distinguished as the normal bronchial whisper, is louder on the right than on the left side, and somewhat higher in pitch on the left side, at the summit of the chest. If at the right summit it exceed the normal disparity, and the pitch be higher than at the left summit, the sign may be distinguished as increased bronchial whisper, and it denotes solidification. If, on the other hand, the sound at the left summit be louder than that of the right summit, there is increased bronchial whisper, representing the solidification at the apex of the left lung.16