biliarii from within. To these may be added, the cellular, parenchymatous, and other substances, affording a third emunctory for the superfluous contents of blood-vessels, by means of exhalents and secretory capillaries every where opening into them. To these contrivances there are only two exceptions, the thyroid gland and spleen.

The extravasated fluids resulting from inflammation are various. The simplest form is that of serum effused into the cellular membrane, as in superficial gouty inflammation ; it is a true dropsy or cedema of the part. The same occurs as a termination of various inflammations; as of the gums, in caries, &c. of the teeth; of the leg, in sciatica; of the joints, in rheumatism; of the lungs, in peripneumony; of the forehead, temples, and eyelids, in erysipelas; in all parts, from external injuries, as blisters, &c. The same kind of effusion is poured out on the surfaces of the serous membranes, as the pleura, pericardium, &c. It is not confined, however, entirely to serous membranes:

"For in certain cases of pulmonary hectic an expectoration often occurs of a dense, hard, globular substance, partly transparent, and partly of a pearly whiteness, which immediately falls to the bottom of the water into which it is thrown, and has much the appearance of thickened albumen." 107.

Dr. P. is of opinion that albumen and fibrine are increased by all inflammatory processes in the constitution. The deposition of fibrine in particular, Dr. P. thinks, may account for various painless, but hard and obstinate swellings, which succeed inflammations, especially about the tendons and joints. Our author believes, and we think with reason, that small parts of the body may be made to unite again, after having been entirely separated, as Dr. Balfour and Mr. Bailey have indeed lately proved.

Another termination of inflammation is the effusion of blood itself. We see this in the bloody spots or streaks in the sputa of bronchitic and pneumonic patients, which, when slight, are always favourable. In pulmonic and hepatic inflammation, however, blood is often fatally effused into the air-cells and pori biliarii. Even from the surfaces of serous membranes entire blood is sometimes exhaled, especially about the period of death, both previously and subsequently. That termination of inflammation denominated Pus is not, even to this day, exactly characterized, since it (pus) is hardly ever procured unmixed with other fluids. Dr. Parry is inclined to believe that real pus may be secreted from unbroken surfaces.

"In cases of hemiplegia," says he, "in which blood is effused Vol. III. No. 9.

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into the medullary substance of the brain, that fluid may be seen in all the intermediate states from entire blood, through what in appearance exactly resembles pus, to complete absorption." 122.

Dr. P. next takes a review of the various morbid, or rather salutary effusions and secretions which result from inflammatory processes, or increased momentum of the blood; previously observing, "that on a great variety of occasions, the effect of inflammation is to increase the natural secretions of the parts affected." But we are of opinion that, "on a great variety of occasions," the contrary is the case, and particularly in one of those instances which he has brought forward in corroboration of his opinions, viz. hepatitis. We have had opportunities of seeing this disease on a much larger scale than Dr. Parry; and from very attentive observation, we believe we may say with safety, that, during inflammation of the liver, there is in reality a paucity of the biliary secretion. We know, indeed, that discharges of morbid bile sometimes take place during the inflammatory process, and are speedily ejected from their irritating qualities; but such occurrences are not to warrant the conclusions which our author has drawn. Our author is of opinion, and with reason, that although these discharges from inflamed vessels are sometimes fatal (as in hydrocephalus or pneumonia for instance,)"the process, in a great majority of cases, is beneficial to the animal frame." 128. Among the fluids effused from inflammation, Dr. P. enumerates that cream-like substance deposited in the cavities of joints, in capsular ligaments, in the sheaths of tendons, &c. which, by the absorption of the thinner parts, becomes what is called chalk-stone, a well-known effect of highly-inflammatory gout, and consisting of urat of soda. The same is deposited in the cellular space between the inner and fibrous coats of the larger arteries, becoming true bone, or phosphate of lime, and producing such distressing effects, resulting, according to our author's observations, from an inflammatory affection of the vasa vasorum; and when on the coronary arteries of the heart, predisposing to syncope angens. Nodosity of the joints, Dr. P. supposes to be owing to " an erroneous deposit of common bone."

It has been shewn, that the capillary arteries have a power of contracting to their natural size, after being preternaturally dilated with blood. This power, however, seems to diminish, cæteris paribus, in proportion to the violence and duration of the distending cause:

"Hence," says our author, "one can scarcely avoid considering the state which follows, as what Dr. Cullen would have called

collapse, consequent on undue excitement; and Dr. John Brown, indirect debility. But whatever name may be given to this state,

the order of facts is not the less true." 135.

DROPSY. One of the simplest and most common terminations of inflammation is extravasation of serum, or one of its constituents; thus the swelling, which often accompanies the cessation of gouty paroxysms, is a true dropsy of the anasarcous kind, following, in free spaces, the direction of gravitation: "where, however, it is considerably extensive, it seems to arise against gravitation relatively to the inflamed part." This phænomenon, Dr. P. thinks, may be explained by supposing that the expulsory power of the exhalents overcomes the force of gravity in a column confined all around. Since we find that in gout, cedema continues to extend itself in proportion as the inflammation in the foot subsides, and often exists long after all symptoms of local inflammation are gone, (( we cannot help," says Dr. P. "attributing its occurrence, in the latter case, to such a state of momentum of blood still existing in the vessels leading to the part originally inflamed, as produces preternatural evacuation by exhalation." And, on the same principle, the anasarca or cedema, extending to a distance from the original seat of inflammation, "originates in a similar condition in the neighbouring arteries and exhalents; both of which appear, from all the phænomena in such cases, to be preternaturally distended with blood." 141. Thus, in œdematous swellings of a lower extremity, following gout in the foot, if we apply a bandage to the foot and ankle, we shall still find an oedematous swelling recur every night above the bandage, and often in a greater degree than before the bandage was applied. Hence we may conclude, that increased momentum is sufficient to produce anasarca or œdema, without the existence of local inflammation as the source from whence the effusion takes place. Dr. P. illustrates this reasoning by the oedematous swellings of lower extremities following scarlatina, and also the ascites which not unfrequently supervenes, both evidently originating in the high phlogistic diathesis then prevailing in the system.

The fluid effused in what are supposed to be idiopathic ascites, hydrothorax, and anasarca, has all the chemical qualities of common serum; and the identity of the fluid thus effused with that which arises from certain degrees of inflammation in the same membranes, is certainly a strong argument in favour of a state in them approaching to the phlogistic diathesis. 143. This idea is farther strengthened by the thickening and opacity of the peritoneum and pleura,

unaccompanied with disease of the liver or other part, which we see in ascites and hydrothorax, and which would justify our inferring a previous topical inflammation in those membranes. This inflammation proceeds in so slow and chronic a manner, with little or no pain or fever, and with only some symptomatic irregularity in the alvine excretions, that the patient is scarcely aware of the existence of important disease till he is alarmed by a preternatural tumefaction of the belly. So, our author has seen hydrothorax slowly arise from a diseased state of the pleura following slight inflammation, accompanied with habitual fever and high-coloured urine, but without the smallest affection whatever of the organs of respiration, till after the lapse of several months, when, at the end of a few days, the patients died, and dissection exhibited copious serous extravasation, without pulmonary disease. 145. Anasarca of the lower extremities is also often preceded in them by local pains, which do not go the length of inflammation, and subside as the effusion takes place. In such cases, we cannot reasonably expect to find the secreting membranes to be always in a morbid state; for here, as in acute inflammation, the exhalation is the cure, or at least the effect of the curative process of the excreting parts. Hence the explanation of Bichat's assertion, that in increased secretions, the vascular system supplying the part, is not generally found more full than on other occasions.

any

The fluid found in the cavities of the brain in hydrocephalus is not serum, or at least contains little of it. It is not coagulable by heat or acids, though a small proportion of albumen is precipitated from it by the voltaic pile. It is worthy of attention, that dropsy is often evidently produced, and when existing aggravated, by many of those circumstances which are known to increase the momentum of the blood, as intemperance gives rise to ascites and anasarca without hepatic disease. From all these circumstances, it is probable, that although serous effusions are usually the consequences of local inflammation of either cellular or serous parts, yet they may occasionally take place from a degree of excessive momentum short of that which would have been necessary to produce either of these two states. As inflammation rarely occurs till some time after increased momentum of blood, so extravasation uniformly obeys a similar law, as may be illustrated by the obvious example of sweating, which rarely supervenes till a considerable time after the increased action of the heart from heat, exercise, &c. On other occasions of increased momentum, as in inflammation, effusion is not always proportioned, either to the mere dis

position in the capillaries, or to the degree of increased momentum; but is relative to the sum of the two taken together. 148.

"Hence it will be found, that in certain states of the capillary system, even the healthy impetus may be sufficient to cause effusion; while, in other states, very great degrees will not produce the same effect, either at all, or else only through the medium of local inflammation. Ib.

This principle, our author thinks, will comprehend all the more essential examples of idiopathic dropsy, as well those styled active, as those attributed to debility.

"In this view, the malady in question, and the state of inflammation, throw on each other reciprocal light; since it appears that both have in common the circumstance of a degree of momentum of blood, which is excessive with regard to the wholc, or a part of the animal system in general, or of that particular animal, or accidental constitution of the animal, which is the subject of the malady." 149. "If these facts be well founded, general dropsy, like the extravasations of inflammation, is to be considered rather as a salutary effort of the constitution to diminish morbidly increased momentum, than as a primary or actual disease."

In this, as in the former case, the effusion, occurring in certain parts, as in the ventricles of the brain, may prove fatal. This principle also illustrates the efficient and final causes why dropsy of various kinds follows venous and glandular obstruction; the arterial blood, thus arrested in its natural course, pouring out its serum through the exhalent extremities of the containing vessels. The phlogistic diathesis, our author thinks, may not be essential to serous effusion, or dropsy; though few dropsies will be found to exist without the appearance of inflammatory crust in the blood, at some stage or other of the disease. We may also conceive that yielding state of vessels, approaching to that of death, which, in order to the production of effusion, does not require the coincidence of excessive momentum.

It ought always, however, to be kept in mind, that in all these cases, the impetus is excessive with regard to the individual constitution, and therefore is speedily followed by the process of effusion. Dr. Parry remarks, that diminished absorption, as a cause of dropsy, is utterly untenable, his observation not having furnished him with a single fact in support of the agency of this cause. We fully agree with him.

HEMORRHAGE.-As hæmorrhage frequently attends dis