the vital functional derangements of the organs implicated, as by the aid of various alterations in the physical properties of those organs,—as, for example, their density, their faculty of generating and of conducting sound, &c. So invariably do these alterations bear a certain and fixed relation to the physical nature of the anatomical conditions with which they are associated, that the discovery of the former is conclusive as to the existence of the latter. And not only the physical nature, but the precise limits and the precise degree of these conditions are disclosed by the alterations referred to, which, for these reasons, constitute their physical signs. Interpreted by the observer, and not by the patient,-incapable, except in the rarest instances, of being feigned, dissembled, or even modified at will,-estimable in degree and extent with almost mathematical precision,-susceptible of indefinite refinement, physical signs, like the whole class of objective phenomena of disease, are of immeasurably greater diagnostic, greater general clinical value, than its subjective symptoms. Physical signs are, in fact, the true indices of the physical nature, extent, and degree of textural changes, and may be regarded as instruments of pursuing morbid anatomy on the living body. But just as their significance is sure and precise, so is the difficulty of mastering their theory and practice positive and great; and hence it is that physical diagnosis has gradually acquired for itself the importance of a special art."i

SECTION 1. THE PHYSICAL DIAGNOSIS OF CEREBRAL

DISEASES.

A few years since Dr. John Fisher and Dr. Whitney, of the United States, published some observations on Cerebral Auscultation, which, though they do not appear to have attracted as much attention as they merit, are yet deserving of our notice, since the diseases of the brain are generally so obscure, and their diagnosis-resting solely upon the plausibility of physiological and pathological induction-is beset with so many difficulties, notwithstanding the great advances which have been made in the study of the nervous system, that any attempt to increase the knowledge of this class of affections is welcome, and deserving of careful consideration. That

A Practical Treatise on Diseases of the Lungs and Heart, Second edition, p. 2.

American Journal of Medical Science, vol. xxii, p. 277, and vol. xxxii, p. 283.

practitioners should attempt by auscultation to ascertain the various conditions of the parts within the thick-walled skull under the influence of disease might naturally be expected, especially when so much was daily being learnt by the same means of pulmonary and cardiac affections. Neither does it seem at all improbable at first sight that, e. g., in the case of aneurisms of the cerebral arteries-the internal carotid, the vertebral, or the basilar-the careful use of the stethoscope might reveal the existence of a bellows-murmur, and so very materially facilitate their diagnosis.

In practising cerebral auscultation, the person to be examined should be in a horizontal position, with his head supported by a pillow; if it be a child, the examination can be most satisfactorily made while it is asleep. In auscultating the heads of healthy children, four different and perfectly distinct bruits are heard passing through the brain, consisting of the sounds produced by the acts of respiration and of deglutition, and by the impulse of the heart and the voice. The first which attracts attention is the cephalic sound of respiration, commencing and terminating with the respiratory act, and produced "by the impinging of the air against the wall of the nasal cavities during the act of respiration." The second sound is that of the heart, the impulse which strikes the ear seeming to be transmitted from a distance: it has been called the cephalic sound of the heart. The sharp, piercing, and vibratory sounds which accompany the act of crying or speaking, and which can be heard over every part of the skull, is termed the cephalic sound of the voice; while the remaining one of the normal sounds of the head is a peculiar, dull, massive, liquid sound, attending the act of deglutition, and known as the cephalic sound of deglutition. As age advances, and the density of the brain and cranium increases, these sounds become modified and somewhat indistinct, while in disease they become remarkably altered, as we shall

now see.

The auscultic phenomena which have been described by Drs. Fisher and Whitney as characteristic of particular pathological states of the encephalon are four,-i. e. 1, the cephalic bellows-sound; 2, the encephalic or cerebral ægophony; 3, the frémissement de cataire, or purring thrill; and, 4, the bruit de poussin, a cooing or musical sound.

The chief of these, the cephalic bellows-sound, can be most distinctly heard in certain of the cerebral affections of children, by placing the stethoscope over the anterior fontanelle. It has its seat and origin in the arteries, and probably in those

situated at the base of the brain. In most cases it seems to be due to compression of these vessels, but any cause which narrows the artery, as inflammation, ossification, &c., or indeed any condition which produces an inequality or disproportion between the size of the vessel and the quantity of fluid to pass through it, will give rise to it. The sound is loud, coarse, abrupt, and rasp-like; it is synchronous with the pulsations and impulse of the heart and large arteries, and with the pulsatory motions of the fontanelle; compression of carotids renders it feeble and indistinct; and nothing resembling it can be heard in the arteries of any other part of the body.

The cephalic bellows-sound is not a phenomenon of health. It cannot be detected in the heads of children or adults who are free from disease, but it has been discovered in cases of cerebral congestion, acute inflammation of the encephalon, hydrocephalus, induration of the brain, and ossification of the cerebral arteries. To discover this murmur is said to be in many instances a matter of no small difficulty, and hence may be explained the fact that many observers have failed to detect it, even after repeated examinations.

The second sound-the encephalic or cerebral ægophony— has been noticed only in those cases of cerebral disease which are accompanied with effusion and extravasation of fluid over the surface of the brain. "In every instance," says Dr. Whitney, "in which I have noticed this hitherto undescribed cephalic phenomenon, it has been connected, and existed only with a state of effusion and extravasation of fluid over the surface of the brain. I have never been able to detect this change in the character of the voice, in simple effusions into the ventricles, nor in any acute or chronic lesion of the brain, except accompanied with effusion and extravasation; consequently I have been led to consider an extravasation of fluid over the surface of the brain as a prerequisite to the development of this phenomenon. Such a state of the brain, moreover, accords with a similar state which is known to accompany a similar phenomenon of the lungs. It is owing, therefore, to the natural resonance of the voice being rendered more shrill and brazen by its transmission through a thin layer of fluid in a state of vibration."

The third sound-the frémissement cataire, or purring thrill, has been heard only in one case of aneurism of the basilar artery, and was supposed to be due to the disease of the arterial tunics.

Lastly, the fourth sound—the bruit de poussin, or cooing or 1 Op. cit. p. 326.

1

musical sound may be considered simply as a modification of the bellows-murmur, seated in the arteries, and occurring in cases of anæmia where the supply of blood to the brain is imperfect or deficient.

The foregoing remarks contain all that is important in the writings of Drs. Fisher and Whitney on cerebral auscultation, as well as all that I can glean from other sources.

The reader will perceive that although much has not yet been accomplished, still something has been done, and it is certainly as well that he should be acquainted with the attempts that have been made. With regard to the results said to have been obtained from the practice of percussion in cerebral disease I hold the opinion of Zehetmayer, that percussion will undoubtedly inform us of the thickness of the skull, but up to the present time, thick and hollow heads have been detected with tolerable certainty without the necessity of percussing the cranium.'

SECTION 2. THE PHYSICAL DIAGNOSIS OF DISEASES OF THE LUNGS AND HEART.

Introductory Remarks on the Structure of the Lungs. The lungs-the organs of respiration-are contained in the cavity of the thorax, one on either side of the spine. They are irregular conoid bodies, the bases of which rest upon the diaphragm, while the apices project upwards, extending slightly above the level of the clavicles. Between the fourth and fifth ribs, near the left edge of the sternum, a small oval-shaped space is left between the two lungs, where part of the pericardium remains uncovered, the remainder of the pericardium and heart being received into a depression in the inner surface of the left lung. The right lung, somewhat broader but shorter than the left, owing to the position of the liver, is divided into three lobes; the left into two.

The lungs are formed of-1, bronchial tubes-composed of cartilaginous rings, muscular fibres, and of mucous membrane covered with vibrating ciliated epithelium-which commence at the bifurcation of the trachea, divide and ramify through the lungs, and terminate in-2, the bronchial intercellular passages, which, according to Mr. Rainey, are simply passages running between, and communicating in all directions with3, the air-cells, or lung-vesicles. These air-cells are small, generally four-sided cavities, communicating either directly with the intercellular passages and bronchial tubes by large circular apertures, or indirectly through the medium of other

'Grundzüge der Percuss. und Auscult. p. 41.

cells; the cells in the central parts of the lungs are smaller but more vascular than in the peripheral portions. The pulmonary membrane forming the cells and supporting the capillary plexus of vessels is thin, transparent, composed of fibres having no resemblance to muscular fibre either of the striped or unstriped kind, unprovided with epithelium, and quite distinct from the membrane lining the bronchial tubes. 4. The plexuses of the capillary vessels entering into the minute structure of the lungs are situated immediately beneath the pulmonary membrane forming the air-cells, so that the most delicate structure alone intervenes between the blood in the vessels and the atmospheric air in the cells. Moreover, the capillaries between the cells are aërated on both sides, being inclosed in the fold of membrane forming the sides of contiguous cells. Lastly, each lung is invested by the pleura, a fine serous membrane, which, being reflected from the pulmonary surface over the internal parietes of the chest, forms a shut sac. From the foregoing it may be concluded that the lungs are merely expansions of a delicate membrane, upon the opposite sides of which blood and air are situated; the latter, by its chemical action upon the former, converting the impure venous blood of the pulmonary artery into the pure, arterial, bright red blood of the pulmonary veins.

Position of the Patient.-In the investigation of pulmonary or cardiac affections some care is necessary to place the patient in such a position that the parietes of the chest may be rendered firm and tense without affecting his ease or comfort, and without being inconvenient to the examiner. When the fore part of the chest is to be examined, and the patient is able to sit up, the best position of all will be sitting upon a chair in the middle of the room, opposite to a good light, with the arms hanging loosely down by the sides, the head thrown back, and the upper part of the body uncovered. To examine either lateral region, place the patient's hand of the side to be examined upon the back of his head, and make him lean a little to the opposite side. To percuss or auscultate the back, let him lean well forwards, hold down his head, and fold the arms across his breast.

The chest may also be very carefully explored while the sufferer sits up, or even while lying down in bed, being turned to either side as may be necessary, and as far as his strength will admit. The surrounding bed-curtains and furniture have

See Mr. Rainey's excellent paper on the Minute Structure of the Lungs, in the "Medico-Chirurgical Transactions," vol. xxviii, p. 581.