using a stethoscope, on account of the uneasiness caused by the pressure of the instrument exciting crying. The advantages of such a course are, however, more than counterbalanced by its disadvantages. Owing to the small size of the thorax in children, and to the readiness with which, in them, sounds from the nose, the larynx, and the throat, are transmitted to the chest, it is extremely important to circumscribe as much as possible the limits within which the different respiratory sounds are perceived. If the instrument is spoken of as a "trumpet," children who are old enough to understand the term, seldom manifest much opposition to its use, especially if they are allowed to touch and play with it beforehand; and infants in whom the chest-disease is extensive, are often remarkably quiet during examination, being usually too much occupied by their own sensations to make any resistance to the operation. Over the seat of dulness, the respiratory murmur is found to be weak or suppressed, or is bronchial, blowing, or cavernous, with increased resonance of voice and cry. As the tissue softens and breaks up, moist crackles are heard accompanying the breath-sounds, or there is merely a click or two at the end of inspiration. This passes, as cavities form, into gurgling, or large bubbling rhonchus more or less metallic.

The stethoscopic signs differ in value according to the part of the chest at which they are heard. At the apices, mere harshness of respiration is insignificant, and prolonged expiration absolutely worthless, as a means of diagnosis. Bronchial breathing is a natural condition between the scapulæ over the site of the principal divisions of the airtubes, and at the apices may be closely simulated by sounds conducted from the larynx. It is advisable that the child's mouth should be open during auscultation of the chest, the laryngeal sounds are then less readily transmitted. In the case of infants, however, this is not easy to manage. Bronchial breathing, if heard at the supra-spinous fossæ,

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and supposing that conduction from the larynx can be excluded, is often the sign of a cavity. In the case, however, of bronchial, blowing, and cavernous breathing, enlarged bronchial glands in contact on one side with the air tubes, and on the other with the chest-wall, may, by their conducting power, simulate these varieties of respiration so closely, that at a single examination it is impossible to give a positive opinion as to the condition of the lung beneath. It is only by careful observation of the succession of these sounds that a conclusion can be arrived at. In the case of pulmonary consolidation and excavation, there will, as time goes on, be a gradual progression from harsh to cavernous breathing, while-if the sounds are due to conductioncavernous, bronchial, and harsh breathing will be found to alternate irregularly with one another. The results of percussion often afford no assistance in these cases, for if much healthy lung intervene between the diseased spot and the surface, or if the disease has excited compensating emphysema around it, the percussion-note may be almost healthy.

All the signs of a cavity may be produced by extensive pleuritic effusion. The diagnosis between these two conditions will be given afterwards.

Bronchial breathing is most significant of solidification when heard at the base. If heard at the apex, in front or behind, conduction from the larynx and enlarged bronchial glands must be excluded before laying much stress upon this sign as evidence of consolidation.

Cavernous respiration at the base is very suspicious of a cavity; at the apex it is only valuable after exclusion of enlarged bronchial glands and pleuritic effusion.

In the case of disseminated miliary tubercles, the physical signs are very much more obscure. There may be absolutely nothing about the chest from which any information can be obtained; the resonance may be perfect, the respiratory sounds natural, and a little sonorous or sub-mucous rhonchus heard here and there, showing the presence of an

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excess of secretion in the air-tubes, may be the only signs to indicate that the lungs are not in a condition of the most perfect health. At other times the sub-mucous rhonchus may be more general, and may be heard from apex to base in both lungs; or sibilant and sonorous rhonchi may be equally extensively audible; or the respiration may be weak or harsh over a variable extent of lung-surface.

Weak respiration is of greater value, as evidence of tubercle, at the base than at the apex ; but at a first examination too much importance should not be attached to it. If it is found to persist for several weeks, or if it occupies the whole extent from apex to base, on one side only, it becomes a sign of considerable significance. Harsh respiration is of little value unless it passes into weak respiration at the same spot, or unless the breathing is weak in intensity and harsh in quality at the same time; it then becomes of more importance.

Anatomical Characters.-The first stage in the anatomical changes depending upon pulmonary phthisis consists in the presence of solid bodies of variable size scattered through the lung, or collected into groups in one particular lobe. These bodies consist of grey or yellow miliary tubercle, and of the large masses resulting from scrofulous pneumonia— the infiltrated yellow tubercle of older pathologists.

Grey granulations are scattered through the lungs, but are usually in greatest quantity in, or may be even altogether limited to, the upper lobe. They occupy the septa between the air vesicles and the submucous tissue of the minuter ramifications of the bronchi.

Yellow granulations are also often disseminated through the lungs. They are not always the result of conversion of the grey; or at any rate small yellow bodies, distinguishable with great difficulty from degenerated grey tubercle, may be produced by other means. Such bodies may be the result of more or less extensive pneumonia occurring in scrofulous and tuberculous subjects. In this

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form of lung-inflammation, described by Dr. Andrew Clark as "epithelial pneumonia," the air vesicles are found to be filled up with a yellow matter, which is seen under the microscope to consist of large epithelium-like cells containing one or two nuclei, of the same cells in a state of disentegration, of free nuclei, and of granular matter. If isolated air vesicles are the seat of this inflammation, their contents are seen as small projecting bodies about the size of a millet-seed-larger, if contiguous vesicles are affected—yellow, hard, and resistant to pressure. When pricked, a yellow purulent-looking fluid sometimes escapes, if the formation is very recent. The coalescence of neighbouring vesicles, filled with the same material, produces masses of yellow cheesy-looking matter, which vary in size according to the extent of tissue involved in the inflammation. Every degree of bulk is therefore found between the solitary millet-seed bodies and extensive consolidation of an entire lobe, or even of the whole lung.

The masses may occupy any part of the lung. They may be seen on the surface as flattened plates, extending in

* Lectures at the Royal College of Physicians, 1866.

According to the views generally held, there are two distinct varieties of inflammation of the lung. One-the simple form of pneumonia-is accompanied by high fever, increased pulse-respiration-ratio, herpes on the lip (very commonly), and undergoes resolution from the seventh to the twelfth day. Here the deposit consists of cells similar in structure to the white corpuscles of the blood, and is believed to be composed of these white corpuscles, which have passed out of the vessels into the air-cells, either by rupture of the capillaries, as Dr. A. Clark considers, or by passage through the capillary wall, without rupture, as is held by other observers. When resolution occurs, these cells undergo retrograde metamorphosis, and are absorbed, or expectorated.

The second variety-the scrofulous pneumonia of some authors, the epithelial pneumonia of Dr. Andrew Clark-occurs in scrofulous and debilitated subjects. Here the contents of the air-vesicles consist of large cells, exactly resembling epithelial cells in structure, containing one or two nuclei. This form is unattended by any sthenic inflammatory symptoms: the material is not absorbed, but softens, breaks down, and leads to ulceration and cavities.

wards for some distance into the substance of the organ, and having a notched, irregular circumference, or in the interior as rounded nodules. Surrounding them may be healthy tissue, or tissue occupied by smaller masses of the same kind, or by true grey tubercle. The solidified tissue may be at the base or the apex, and in one lung or in both; usually only in one.

When a section is made of one of these masses, the surface is found to be dry, of a straw or grey colour, and sometimes marked with streaks or spots of black pigment. The fracture is granular, and the substance breaks down under pressure, the more easily in proportion to the newness of its formation; for as time goes on the material is found to become tougher and denser, less granular, and more opaque. Often the lobules, by coalescence of which the mass is formed, can be distinctly traced out, depressed intersecting lines being seen, which are the areolar partitions separating the lobules from one another.

The consolidation resulting from scrofulous pneumonia may be the only pathological condition found, or it may be accompanied by true grey or yellow tubercle. It is not uncommon to find the two conditions combined, for the presence of this form of pneumonia appears to be a determining cause of the development of true tubercle, which may then be looked upon as a secondary formation. Besides, the tubercle, originally uncomplicated, may excite inflammation in the lung tissue around it: its bulk will then be increased by pneumonic solidification forming at its circumference. Consolidation of considerable extent may, however, result from the aggregation of the tubercles in one part of a lung without the supervention of pneumonia. This usually occurs at the apex, and the detection of the true character of the consolidation is one of the most difficult questions in the diagnosis of pulmonary phthisis.

After the consolidation, tubercular or other, has existed for some time, certain changes take place in it. Of these,