which are not circumscribed by a definite boundary, but gradually become diffused, and insensibly lost in the surrounding pale tissue. This increase of colour arises from the injection of the capillaries of the spot, and expresses the condition of true, though limited, capillary hyperæmia. If the catarrhal irritation increases, the patches extend and coalesce, and the colour of the affected part becomes darker; and when the irritation has reached its maximum of intensity, the membrane assumes a bright vermilion-red bue. At this period there is a deficiency in the natural secretion of the membrane, and when the affection is seated high upia the wind-pipe, or extends no farther than the larynx, it is at this stage that hoarseness exists. It may be observed here that catarrhal irritation invariably proceeds from above downwards; and that, supposing the trachea to be the seat of the original catarrhal attack, there would be almost a certainty, that if

Sectio cadaveris twenty-four hours after death. The trivial, and receive no very great attention on the part body was œdematous over the entire surface ; plentiful of the patient; nevertheless, a condition apparently serous exudation from every tissue as the knife passed so trifling, and accompanied by no great amount of through the abdominal and thoracic parietes; a mode- | physical disturbance, may, by its tendency to recur rate amount of clear serum was present in the cavity of again and again, under favourable circumstances, and the abdomen. The lungs did not collapse on raising the often does, lead to serious mischief, and ultimately sternum, but were attached by firm bands of tissue to even to fatal consequences. According to the best the pleura costalis; no trace of recent plastic exuda- authorities, in the earliest stage of acute catarrhal tion could be detected; the lungs on their anterior affection, distinct portions of the bronchial mucous surface, and particularly about the middle lobe, pre-membrane exhibit patches of a fine rose-red injection, sented many emphysematous patches, one or two of the size of a filbert; the margins of the inferior lobes were also covered with emphysematous vesication; the posterior and inferior portions of the lungs were dense, with cadaveric infiltration, a plentiful sanguinolent serum (frothy,) exuding freely on a section being made. The mucous membrane of the bronchial tubes was turgid and swollen, of an intense dark, madder-red colour, and from them into the lesser series the colour passed into a purplish violet, and presented the appearance as of intense venous hyperæmia; the larger tubes were smeared over with a glutinous. tenacious, and very adhesive secretion, and many of the smaller tubes seemed quite blocked up with this gelatinous mucus. It was of a faint fawn-colour, and at no point could any appearance of yellow muco-purulent secretion be detected. Under the microscope this exudation had a fibrinous appearance, and exhibited many granular cells; none could be found that pre-it extended, it would descend to the bifurcations of sented any of the characters of pus-globules. The heart was much enlarged, but uniformly so; no valvular thickening nor opacity; the walls were relatively thin in respect to the increased capacity of the auricles and ventricles; it weighed twenty ounces. The liver was not unhealthy in appearance, presented indications of a large amount of portal congestion, and weighed fortyeight ounces; the kidneys were free from any morbid appearance, the right weighed six ounces, and the left five and a half. The brain was not examined.

the bronchi, rather than ascend to the larynx. This is more particularly noticed in epidemic catarrhs, where the original attack, commencing as coryza, and seated in the Schneiderian membrane, extends to the pharynx, thence to the larynx, and if the attack be severe and neglected, continues to the trachea and bronchi, and ultimately extends to the minutest branches of the air-passages. But the reverse is never observed, the catarrhal irritation never proceeds from within outwards,-from the smaller tubes upwards to the wind-pipe and larynx.

This case explains to us many of the pathological conditions of pulmonary catarrh, bronchitis, and em- I have already observed, that in the earliest stage of physema. Pulmonary catarrh is one of the most fre- the affection, there is a diminution, even total absence quent and commonest precursors of the severer and of the ordinary lubricating secretion of the part. The more fatal forms of bronchitis. Pathologically it can air irritates the undefended and irritable surface, and be said to differ from bronchitis only in the amount excites a dry, frequent, and harrassing cough. In the and intensity of the preceding hyperæmia; the usual mildest cases, this state of capillary congestion and products of inflammatory action, pus, and plastic exu-deficiency of secretion is soon followed by the pouring dations, being the result of the more intense morbid action; while in the milder affection, epithelial cells, granular corpuscles, and fluid mucus, are generated and expectorated to à greater or less extent. To the latter the term catarrh, or pulmonary catarrh, is usually applied; while, to express the former, we employ the word bronchitis. I propose to examine the pathological conditions of these affections somewhat minutely, as the case before us presents me with a favourable opportunity practically to illustrate these morbid conditions.

Catarrhal affections of the mucous membrane of the trachea and larger bronchial tubes may be reckoned among the most frequent derangements of the system, and except in rare cases, are from the first treated as

out of a thin pituitary fluid, which soon presents many minute grey points or striæ, mixed with many air bubbles. Under the microscope, this secretion is observed to be composed of epithelial cells-even layers of them-in great abundance, suspended or floating in a clear mucous fluid, and often mixed with many granular corpuscles. Proportioned to the intensity of the preceding capillary injection, changes take place in the secretion; it becomes thicker, opaque, slate-coloured, greyish yellow, even yellow, and then assumes a more evident muco-purulent character. As the irritation subsides, this secretion gradually diminishes in quantity and consistence; epithelial cells in diminished number are alone visible, and the mucous membrane gradually and slowly

LECTURE ON CLINICAL MEDICINE.

returns to its normal and healthy condition, regular epithelial layers being formed, as the more superficial are constantly and uniformly thrown off.

In the more severe forms of bronchial catarrh, where a more extended surface of mucous membrane is from the first the seat of morbid action, and where the capillary hyperæmia is not confined to the superficial | mucous layer, but involves a more expanded series, and injects even the vessels of the sub-mucous tissue, the term bronchitis more usually applies. The several pathological conditions before noticed, are here much aggravated. The mucous membrane is no longer of a bright rose-red colour, but presents a deeper tint, even madder red; in the case before us purple madder. | Consequent on this large amount of turgescence of the capillary vessels, (upon which this change of colour depends,) is tumefaction of the entire series of mucous tissues. A swollen turgid state of the mucous membrane is now observed; the effect of this is a diminution in the calibre of the air tubes,-a coarctation of them, a lessened diameter. An increased frequency in the respiratory movements now compensates, or is an effort to compensate, for the diminished capacity of the air-tubes; and we notice in the severer forms of the disease, a gasping effort during inspiration, attended by very distinct wheezing sounds on expira tion; these are distinctly heard, even without the aid of the stethoscope.

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we have some evidence in this case, which must not be omitted, and that is the presence of plastic exudation; it is also known as fibrinous exudation, and is the inflammatory exudation of Vogel and other modern pathologists. The mucous membrane is as capable of generating this product of inflammatory action as other tissues, although it is certainly not so frequently observed as in the serous and cellular series. It would appear to be dependent on the amount of pre-existing capillary hyperæmia, the intensity of which, instead of generating granular cells, which are rapidly converted into pus-globules, and thus forming a true muco-purulent secretion, is attended by the exudation of a plastic lymph, which fills the smaller tubes and takes their form; and if the disease be fatal at this stage, this coagulated matter may be drawn out from the smaller branches, and in this case you witnessed its tenacity to be sufficient to allow it to be drawn out. In croup this exudative product extends over a large portion of the tubes, and explains the peculiarity of the stringy shreds expectorated in this disease. In the adult, if life be prolonged, this inflammatory exudation soon becomes purulent, pus-globules being very soon generated in it. This change facilitates its excretion, rendering it more fluid, less tenacious, and consequently more easily expectorated.

There can be no doubt, notwithstanding the imperfect history of this case antecedent to admission, that pulmonary catarrh had existed for some time, perhaps in a chronic form, and that in all probability the patient had experienced repeated attacks for some winters past. The enlarged condition of the heart strongly favours this view, for derangement in the structural condition of this organ is one of the most frequent causes of the perpetuation of chronic catarrhal affections of the pulmonary organs. A catarrhal predispo

disease, tend to mutual aggravation. The catarrhal condition gives rise to frequent cough, often paroxysmal and suffocative; venous turgescence results. The violent expiratory efforts of coughing convey an impulse back on the right ventricle; in consequence of the disturbance the current of blood suffers from the circulation from the right side of the heart into the lungs being impeded, dilatation of this cavity follows, with a corresponding increase in the general mass of Increase of volume produces increase of power, and causes the blood to circulate in the pulmo

Now all these conditions were present in the case under consideration; and the physical signs recorded in the case book are very expressive of the conditions just explained. There is no respiratory vesicular murmur to be heard, the only sound at first is a sonorous rhonchus, either accompanied or followed by a variety of irregular murmurs, sometimes simulating the gentle cooing of a pigeon, at others whistling and wheezing. The lessened diameter of the air-tubes from the tumefac-sition in the bronchial mucous membrane, and hearttion of the sub-mucous tissue, is the cause of these sounds. As secretion becomes established, the turgescence of the membrane is relieved, but the air passing and re-passing over and through the tenacious matters in the tubes, produces the bubbling sound, heard so soon as secretion is accomplished, and to which the term mucous rhonchus or mucous gurgling is applied. This sound differs somewhat, according as it emanates from the larger or smaller tubes, and the study of that distinction is of much practical consequence. The mucous gurgling of the small tubes was very palpably present in this case, and you had an opportunity of hear-nary tissues with a force proportionate to the aug: ing its peculiarity. When the catarrhal irritation extends to the smaller tubes, a similar series of changes takes place; the secretion at first scanty and thin, accompanied by frequent, urgent, and almost suffocative cough, becomes more abundant, opaque-a yellowish mucus, tenacious and frothy, and in urgent cases, assumes the qualities of a muco-purulent fluid, in some cases possessing an almost cream-like consistence. This, as convalescence proceeds, becomes again thinner-more fluid, till in the stage of chronic bronchitis it has become a perfectly white frothy fluid, colourless, and oftentimes extremely abundant.

There is yet one other pathological condition in the severe and more acute forms of bronchitis, and of which

the organ.

mented volume. A condition of passive hyperæmia is perpetually present, which promotes, if it does not originate, the susceptibility to catarrhal irritation. With such predisposing causes it is not to be wondered that acute bronchitis should supervene, and should run a rapid and fatal course. Inflammatory exudation forms in the smaller bronchi; blood imperfectly oxygenated circulates through the left side of the heart, and reaches the great central organs of the frame; its action on the brain is first to induce torpid senses, the countenance becomes livid and purple, the surface becomes œdematous, the dyspnoea becomes more and more urgent, coma supervenes, and death then closes the painful and distressing struggle. The existence of emphysema

on the inferior margins, and on the surface of the to the vessels (the protoplasma.) We are precluded lobes, must be taken as collateral proofs of the exist- from making this direct satisfactory and conclusive ence of some long-standing affection of the pulmonary observation in the human body, because there is no organs, attended most probably by violent expiratory accessible part sufficiently thin and transparent for efforts, as in coughing; but the subject and patho- the purpose; but we have cogent reasons in the logical conditions of emphysema I propose to treat of analogies of life and function—in the composition of on some other occasion. the textures and the blood-for concluding, that in man, analogous or similar irritants are followed by similar results. This conclusion, drawn from analogy, is substantially corroborated by the fact, that in the human body, colourless cells greatly abound in the blood drawn from vessels that are experiencing any irritative or inflammatory action.

MORPHOLOGY OF THE TEXTURES.

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margin and is in fact an extension, of the vascular | linear. The dark portion, a, is one half of the colume wall.

These stages of nutrition will be more readily comprehended by referring to the wood engraving, which represents one half of the diameter of a small bloodvessel in the transparent membrane of a human embryo, at two months, that is to say, in a texture in a state of rapid growth or active metamorphosis. It was copied from the microscope, and is magnified 750 diameters

of red blood lying in the centre of the vessel; the red cells are many of them nucleated, and larger than in the blood of an adult, and lying obscurely amongst them are several colourless-cells-various in dimensions-some very large and filled with a colourless matter mixed with molecules. Atb is a transparent layer of colourless matter or protoplasma, lying between the column of the red blood and the wall of the vessel;

Fig. I.-Half the diameter of a small blood-vessel in the transparent membrane of the human embryo at two months. a, column of red b'ood. b, layer of colourless matter, with cells, granules, and molecules, between the red blood and the coherent wall of the vessel. c, a texture composed of fibres, cells, and nuclei, forming the wall of the vessel. d, the coherent cellular texture forming the membrane.

d.

Fig. II-A section of the same vessel perpendicular tot he axis, shewing the same series, blood, protoplasma, texture, (parov upaoμa,) and cellular parenchyma. Itappears to me, that the subject of secretion, the growth of the embryo structures, and the phenomena of inflammation, would be more intelligible were we to use terms expressing more accurately the stages of nutrition, as revealed by the microscope:-(a) blood-(b) protoplasma-(c) prot-uphasma (d) parencehyma. I well remember the late Dr. George Pearson, five and twenty years ago, insisting upon the distinctions between coagulable and coagulated lymph,

In bringing my observations for verification to the test of the microscope, I would fain remark, that the observer should bear in mind the minuteness and delicacy of those portions of structure that can alone be submitted to high microscopic power, and the unavoidable disturbances that necessarily ensue when it is requisite to take very thin sections, and therefore that decisions pro or con should be based not so much upon the isolated results of one or two hasty trials, but rather on the tenor of the indications derived from a greater number.

in it are seen several colourless cells of various sizes, | onward in new directions, must find themselves at last filled with molecules, also smaller granular particles; protecting shadows in the rear. and numerous isolated molecules. At c is the wall or coat of the vessel, (the prot-uphasma or first texture,) composed of numerous colourless cells or nuclei embedded in a mass of nascent fibrils, which have, in this example, hardly more coherency than the fibrils of a tough mucus. Granular particles and molecules are seen within these colourless cells or nuclei, and the fibrils pass around and between them. Numerous red cells of irregular shape are seen mingled with the colourless elements,-cells, nuclei, and fibrils,— of the vessel's wall, or coat; but these have all the appearance of being accidental and due to the manipulation necessary to render the texture a microscopic object. Atd is a portion of the transparent cellular membrane itself—the parenchyma ; it is evidently an extension or expansion of the wall of the vessel, and no unalterable barrier exists to separate it from the protoplasma—every element is in progress of change.

In any departure from the law of the nutrition of a texture,-from the law of the morphology,—it must be a very difficult question to determine where the first unconformable step commences, whether in the blood a,—in the lymph or protoplasına 6,—in the wall of the vessel c,—or in the textured? It is very common to read about diseases of the blood, yet all must be dark and unsatisfactory to any one that has observed the relations between the blood and the textures by means of adequate power through the microscope; and certain it is, that no practical conclusions can be established respecting health and disease until the stages of nutrition, the reciprocal actions between the blood and the solid textures, be established. present the notorious fact of red blood, administering to the rapid increase or deposition of colourless textures, lymph, mucus, and pus, remains, in respect of any well-directed scientific investigation, a glaring instance of theory, hypothesis, and conjecture. Critical physiologists seem afraid of using their eyes, though they battle boldly with assertions.

At

If a section of this vessel were made across it, perpendicular to its axis, we should have a column of blood in the centre (a), consisting of red and colourless incoherent cells, suspended in the blood-fluid; next to it will be a layer of colourless lymph or protoplasma (b), consisting of a viscous matter, mixed with molecules and colourless cells; next to that is the proper coat of the vessel (c), the first texture varying with the morphology, and consisting in this case of delicate fibres, intermingled with molecules, granules, and colourless cells or nuclei; and lastly, as an extension of the vascular wall, the proper texture or parenchyma (d),—this texture shewing what the morphology has been, and the existing vascular wall indicating what it is or will be. A similar section of a vessel that has been irritated in the frog's foot, When the growth and nutrition of a texture of any would exhibit the same thing. Hence, then, the kind, whether animal or vegetable, is normal, its conclusion stated in the "First Series of Researches," elements are reproduced or multiplied, its form evolved, p. 30, respecting the analogies between active growth and its characteristic qualities and secretions established and inflammation, is fully borne out by these subse-by a metamorphosis of the nutritive elements, supplied quent investigations.

These things, let it be observed, are not matters of surmise and conjecture, but of demonstration, and cannot, therefore, be set aside because they do not square with received and hypothetical notions. It is very easy to throw discredit upon microscopical facts and conclusions by a flourish of the critical pen, and a flippant style of remark, little suited to the occasion; but Nature marches on, although the critics write, and is ever ready with intelligible answers to those who faithfully interrogate. A florid appeal to existing sympathies may be for a time successful. Warm-hearted spirits contend stoutly for their convictions; and settled opinions are difficult out-works to carry, though Nature herself be battering at the walls. But those who, in the ardour of their defence, merely uphold their own opinions, when truth and science are rolling

VIII. INFLAMMATION.

from without, in accordance with the law originally in force in the primary conformation of the parent organism from which it sprung. Every change,— every metamorphosis,—every action,—and every product, yielding or conforming to the law, is an integral element of the complex phenomenon termed health; and every action or product deviating from it, is an element of disease.

It is not my intention now to enter upon the multiplied details of inflammation or inflammatory products; hereafter we shall have occasion to return to the subject, and examine more particularly the nature of its manifold results.

We have seen that any irritation of a vascular texture, is productive of an increased amount of nutritive matter, which is deposited from the circulating blood, upon the walls or inner boundary of the vessels.