Haller, that the force of the heart alone, in health, is adequate to the task of carrying on the march of the blood through its entire circulation. He concludes, that muscular contraction in the vessels themselves, would just as much impede the ingress of a new quantity of blood, as promote the egress of that already existing in them. However it may be explained, it is known, that certain vessels become unusually distended with blood, not only from excessive impulse by the heart, but without that impulse, as where shame fills the cutaneous arteries of the face, neck, &c. One of the most important phenomena of the animal frame is, that after vessels have been more or less robbed of their blood, a contrary state succeeds, termed reaction, altogether inexplicable, but on the principles of vitality. From our author's observations on the structure and functions of the sanguiferous system, we shall only extract the following passage.

"The arteries and veins being in a state of health always full, and the blood being incompressible, that fluid may be considered as if it formed a continuous solid column all the way onwards from the mitral to the tricuspid valves. Hence, at every systole or contraction of the left ventricle of the heart, the shock acts at the same instant throughout the entire circle.” 34.

66

Our author justly observes, that could we calculate, from the heart's action, respecting the proper quantity of blood in the whole, or any part of the system, great benefit would result; but the pulse is now as it was two thousand years ago- res fallacissima." Thus, in many diseases, the pulse of the radial artery will be small, while that of many other tangible arteries will be full and strong. Again, the face and head will often be flushed and hot; the pulse of the carotids strong, full, and bounding; while all the extremities are cold and pale, and the pulsation of their arteries small and weak. In gout, and local inflammations without fever, the arteries leading to the diseased parts will throb violently, while other arteries are tranquil or below par. This remark ought to be kept in mind, as it would often lead to the detection of disease. A general, but not universal law of the human constitution is, that excessive morbid determination to two different parts shall not exist in the same person at the same time. This is exemplified not only in gout, but in several other diseases; for he who has a catarrhi to-day, may have a fit of the gout to-morrow; then a discharge of blood from the hæmorrhoidal veins, and shortly afterwards, a rupture of the medullary substance of the brain, from sanguineous effusion. This change of deter

mination is a most interesting subject in animal pathology, and has been long caught at in the treatment of diseases, though with not so much success as could be wished. Thus it is usually in vain that we attempt to solicit to the extremities that excessive determination of blood which is called gout, though we employ topical heat, friction, blistering, &c.

Our author is of opinion, that although a suspension or cure of a disease may, perhaps, be occasionally produced by certain violent causes, (as he had seen asthma suspended by a blow on the head) yet, in the common order of conver sions, the new affection or determination is, in point of time, either co-existent with the disappearance of the old one, or more usually subsequent to it; so that in reality, we cannot cure a malady by bringing on the gout, but must first cure the malady, and then, in a predisposed constitution, there is a fair chance that gout will supervene. The same prin ciple is applicable to a great number of other occasions of the highest practical importance, as will be hereafter shewn.

Inflammation and its consequences. After enumerating the various characteristics of inflammation, as it affects different tissues, our author remarks that, of that termination strictly called resolution, or return of the colour and size of parts to precisely their former state, without any discharge, he never met with a single instance. In all these terminations, our author asserts, and we are perfectly of his opinion, that some exhalation from the over-distended vessels takes place, either into the cellular substance of the part, or neighbourhood, or from the cutaneous surface itself externally, or membranes, as the pleura, peritonæum, &c. internally. Of the other terminations we need not speak, but the foregoing remark is to be borne in mind. When constitutional symptoms accompany local inflammation, if blood be drawn in a projecting stream from a vein in the arm, and received into small vessels with polished internal surfaces, and suffered to cool slowly, it will exhibit a coat of fibrine, or what is called the inflaminatory buff. But if other portions of blood be taken from the same patient at the same blood-letting, into larger vessels, or into one with a rough inside, as queen'sware, though they be first drawn, and having the freest flow, no such crust will be seen. This ought also to be borne in mind. Although this appearance affords a presumption of some local inflammation, it is not absolutely decisive. It occurs during pregnancy-in morbid determinations, as hæmorrhage, &c. and also at the commencement of synocha, before any local inflammation exists. It also is occasionally

seen in the blood of very old persons, and in those of a nervous disposition, where there is total exemption at the time from topical inflammation.

Dr. Parry, by a long chain of reasoning, attempts to prove, contrary to the theory of Dr. Philip, that in all inflammations, there is not only dilatation and increased quantum of blood in the vessels of the part, but that there is an increased velocity or momentum of the vital fluid, particularly when to the local inflammation is added general fever. Of this increased velocity we much doubt, notwithstanding the arguments of our author; nor has he convinced us of the "influence of the systole of the left ventricle on the returning venous blood," because "it frequently happens, that in gouty inflammation of the wrist, blood taken from the cephalic vein is propelled in jets, as strong as those from the temporal artery, and precisely synchronous with the pulse in the radial artery in the other arm." 78. We think that this curious phænomenon (which we have witnessed in many instances where there was no gout or local inflammation at all) might be accounted for otherwise than by supposing that the systoles of the heart "extended their projectile force through the capillaries, and nearly back through the entire course of the circulation."* 79. Dr. Parry offers some ingenious and sensible observations on what is termed the "proximate cause" of a disease, defining it-" that phæ nomenon, in the body or part, most immediately preceding the state which we call disease, without which previous phanomenon, the discase is not known to exist." 91. In this point of view, an increased momentum in the velocity of the

If a heart be taken from a living animal and put into warm water, it will continue to dilate as well as contract, for a considerable time. If the heart of a turtle, for instance, be held in the hand, the force of dilatation is just as great, or nearly so, as that of contraction. Why then should not the dilatation of the cardiac cavities act as decisively in abstracting blood from the venous system, as the contractions of these cavities in propelling it through the arterial? We see no reason to the contrary; indeed, we firmly believe that the heart acts in this double capacity; and that the great object of the trunks of vessels is to convey the blood to the capillary system, having the power of adapting their calibres to the ever varying current through them. The uses of the capillary vessels, we believe, to be very different from, and very much more important than, that of propelling the blood. They have secretion to perform in every part of the system-in the muscles as well as in the glands. They have to change the blood from its arterial to its venous state, whatever may be the nature of that change. These important offices, however, are not sufficient in the eyes of many physiologists. The capillaries must circulate the blood, although there is a most powerful and wonderful organ for that express purpose! Rev,

blood through a part, and also a dilatation of the vessels of that part, may be considered as the proximate cause of inflammation.

Speaking of the process by which Nature cures an inflammation, our author justly observes, that after increased action, the heart generally falls into a state of unusual quiescence; while, at the same time, the general mass of blood is more or less diminished: (for instance, by the diminution of increment during all inflammatory affections.) It is, therefore, difficult to say, whether an exhaustion of the heart, in consequence of over exertion, or an abstraction of a quantity of that blood which is so great a stimulus to its action, be, in this case, the chief cause of its quiescence: both probably concur. 94.-On the other hand, if, by undue stimulation, too sudden a restoration of the plethoric state succeeds, and the heart is again excited to excessive action, the local disease, or some vicarious one, is readily produced. This we have so frequently seen bring on relapses after febrile diseases, that we heartily concur with Dr. Parry, when he deplores the mischief that too often results,

"When, under the delusive notion of strengthening the patient, he is pampered with full diet, and stimulated with every description. of drachms, whether solid or fluid, which the elaboratory of the cook, the vintner, or the apothecary can supply." 96.

In fact, the quantity of blood, suited to the salutary performance of the circulation, is by no means always the same, even in the same person. Thus, a man in the prime of life and health shall habitually have a considerable fulness of the sanguiferous system, yet enjoy an exemption from dis

ease.

"But should the same man, after having been emaciated, suddenly grow full of blood, some violent disease, or succession of diseases, will usually again occur, and reduce the habit to its former state of emaciation."

A multifarious series of this kind will. sometimes occur, during convalescence from long and violent diseases; and, in other cases, where health and strength have succeeded to great extenuation, and have continued for months, and even years, no sooner has the habit, by degrees, recovered its prior fulness, than the same, or a similar acting disease, shall return, and reduce the patient to another emaciation. This course we see continually exemplified in gout, erysipelas, and various other diseases, which are called constitutional.

"And, indeed, they are so frequent," says Dr. P. "that one cannot help considering the increased action of the heart, and the general circumstances of the disease connected with it, as natural

efforts to remove a degree of fulness incompatible with the due performance of the healthy functions of that individual constitution. P. 97.

Under circumstances of previous reduction, from whatever cause, what morbid effects do we not daily see, even from an improper meal- from a strong mental emotion-from watching-wine, &c. which, in health, would never be noticed? Is is not, that in such cases, the heart is more susceptible of the stimuli applied to it?

Dr. Parry next enumerates the various structures of the human body, according to the arrangement of Bichat, and while he admits that each tissue is subject to its own peculiar modifications of disease, in general, he yet remarks, that the disease of one tissue will sometimes spread to another; and doubts "whether, in all the different textures, there is not one component or constituent part which is primarily affected in that morbid change called inflammation." 100.

It has been before remarked, that all terminations of inflammation are attended with more or less extravasation, and the same so commonly occurs in cases of general increased impetus, as in sweating after strong exercise, exposure to heat, palpitation of the heart, fever, &c. in all of which, a reduction of the increased impetus follows the effusion, that we cannot help conceiving the evacuation to be a process expressly designed for the purpose of mitigating or curing the disease.

Wherever important functions are to be performed, there we find a large supply of blood, by means of arteries terminating in an infinite number of capillaries, and disposing those very parts particularly to congestion or inflammation. But the benevolent author of our existence has made ample provision against these occurrences. Thus these various parts or organs are abundantly furnished with exhalents or secretory vessels from their capillarics. First apparatus, a simple surface, as the skin and mucous membranes. Second, natural cavities, the internal surface of which is lined with similar membrane, as the stomach, bowels, bladder, &c. Third, discontinuity of substance, forming virtual, though not often real cavities, into which exhalents open, as the cellular system, ventricles of the brain, medulla oblongata, nerves, duplicatures of the pleura, peritonæum, pericardium, synovial receptacles, &c. Fourth, an excretory duct or ducts, as in the mammæ, liver, kidnies, &c. &c. Most of these organs have a combination of two of these circumstances of structure, so as to acquire a double power of evacuation. Thus the lungs have pleura without, and mucous membrane within. The liver, peritoneum without, and pori