science advances, and its cultivation is zealously carried on, so much the more will practical views and experience become the common property of all physicians who combine theory and practice; and that which was formerly regarded as the exclusive property of the medical pioneer will be open to all-will be almost the common stock of all who strive to obtain it.-P. 4. The vast importance of chemistry, especially in relation to those numerous diseases which are connected with the fluids of the animal body, is generally recognised in the present day; but, owing principally to the difficulty of the enquiry, a custom has arisen of regarding this subject as belonging to a separate science to which the term "Pathological Chemistry" has been given. That this disseveration must retard the medical knowledge of many important diseases, is sufficiently obvious; instances of serious if not of fatal mistakes, arising from this cause, are not indeed of rare occurrence; and we therefore extract the judicious observations of the author respecting the practice just noticed. "In the investigation of delicate points connected with pathological histology, the miscroscope is indispensable, and the application of chemical re-agents must be observed under it. Chemical analysis is, indeed, of the greatest importance to pathological anatomy, being the only means by which we can on several points obtain the desired information. At present, much to the detriment of the science, chemical investigation is little pursued in conjunction with pathological anatomy; but assuredly the time will soon arrive, when chemical analysis will be deemed just as indispensable to the prosecution of pathologico-anatomical investigations as the microscope is at present, and when every follower of this science will consider chemical analysis so essentially requisite, that if his own time and opportunities prevent him from carrying it out, he will employ a chemist, under his immediate guidance and direction, to undertake it for him."-P. 11. The two great sources of accurate knowledge in pathological anatomy are, as the author affirms, observation and experiment; the former being the principal means of investigation as far as the human body is concerned; whilst the latter, for obvious reasons, is almost exclusively restricted to animals. It is hardly necessary to combat an objection frequently urged in former years, that the results obtained from pathological changes induced in the lower animals, are not trustworthy when applied to man. Two of the most ordinary phenomena presented to the notice of the practitioner, the reparation of fractured bones and inflammation, have been elucidated almost exclusively, as regards their essential characters, by experiments and observations made on living animals; whilst, as concerns the restorative process in wounds of the intestines and divided arteries although more has been learnt from the inspection of the human body than in the preceding instances, yet the most precise and satisfactory information has sprung from well-devised experiments practised on the brute creation. It is somewhat strange that this objection should ever have arisen, since no one could be found to deny that great light has been thrown upon many interesting branches of pathology by diseases occurring in the domesticated mammalia. For these reasons we are fully prepared to coincide with Dr. Vogel, that conclusions drawn from this source are not only admissible, but that comparative pathology and pathological anatomy afford as much assistance in the prosecution of this science in relation to man, as comparative anatomy does for the thorough comprehension of human anatomy and physiology. 1847.] Proper Mode of Investigation. 431 But to give value to any mode of investigation, the facts must be multiplied and scrupulously weighed. Limited observations and hasty generalizations have been the special bane of medical science, not merely by leading to error, but by tending to throw discredit on the very means by which of all others the most assured results are to be attained. In short, that science, for such it is, in which so many of the great questions affecting civilized communities have found their solution, namely statistics, must be applied to that which lies at the bottom of all enlightened medicine and surgery-pathological anatomy. True it is, that to apply the statistical method to morbid anatomy, is a much more difficult matter than to determine the mean duration of human life, or the average age at death; for, as the author observes, in proposing as a problem the question whether scirrhus and tuberculosis exclude each other, "although physicians are not likely to dispute whether or not a man is really dead, there are few points on which there is more difference of opinion than whether a tumour is to be regarded as of a scirrhous nature or not." There are not then, at present, the data requisite to enable some second Newton to give to pathology its laws and principles; an additional reason this for all who are interested in the future progress of medicine to imitate our author. "In our science," he justly observes, we must follow the examples set us by the astronomers, magnetists, and meteorologists (and he might have added the geologists), who continue for years to carry on the most careful general observations, and to make them public property, in the hope that the general laws which they fail to establish, will be developed by their successors."—Introduction, p. 18. In the volume now translated, Dr. Vogel treats only on the generalities of morbid anatomy; a second volume will follow, in which the special department, or that relating to changes in the individual organs, will be comprised; and, as Dr. Day has undertaken the translation of this concluding part, the English reader will soon be in possession of one of the most recent and complete treatises that have appeared in relation to pathological anatomy. Although we feel it but just to the author to speak thus favourably of his well-known work, we cannot withhold the expression of our opinion, that it is valuable rather on account of presenting a comprehensive epitome of the existing knowledge, than for the extent of original observation in reference to microscopy as applied to morbid anatomy. And further, this treatise, in which the new system of pathology is, without reservation, adopted, appears to us to be particularly deficient in the application of the great discoveries made of late years in structural and philosophic anatomy, and which must, for the reason just stated, be regarded as a fundamental defect: the justice of these remarks will, we think, become apparent in the course of the present article. The general scope of this first division of the subject will be understood by the following sketch of the order, in which the different morbid changes are discussed. "We commence with abnormal collections of fluids in the body-of the gaseous (pneumatoses), of the aqueous (dropsies). The latter are divided in a manner that seems natural and practically important, although not hitherto adopted; namely, into serous, fibrinous, and false dropsies. Then comes a sketch of the morbid changes of the blood as far as they are at present understood. This is succeeded by a chapter on pathological epigeneses, which from their nature occupy a very considerable space, and by a brief sketch of the changes which the tissues undergo in their physical properties, together with some remarks on the manner in which morbid changes in the elementary tissues are connected with each other. The next chapter treats of the independent organisms which occur in the human body, as causes or consequences of morbid changes (parasites.) Then there is a chapter devoted to congenital pathological changes (malformations), and we conclude with a notice of the changes occurring in the body after death."-P. 20. The second Chapter contains some interesting remarks on the various forms of Dropsy; though the author has hazarded some opinions, the correctness of which appears to be somewhat doubtful. He distinguishes in this affection three distinct forms:-serous dropsy, in which the fluid is identical in its qualitative chemical composition with the serum of the blood; fibrinous dropsy, in which the fluid contains dissolved fibrin, and in its chemical composition resembles the plasma of the blood; false dropsy, in which the fluid differs essentially in its chemical composition from either of the preceding forms; this is, in fact, not dropsy at all, but merely an accumulation of a natural secretion, owing to an impediment to its exit, as of urine (hydrops renum), of bile, &c. These forms not only thus differ in the physical and chemical characters of their fluids, but, as Vogel believes, likewise, very essentially in their causes. Thus he is of opinion that serous dropsy owes its origin to a permeation of the serum of the blood through the walls of the veins; whilst fibrinous dropsy arises from a permeation of the liquor sanguinis through the walls of the capillary vessels. The cause and mode of origin of serous dropsy are thus explained: we are induced to believe that serous dropsy always proceeds from the venous system, and that it takes place as soon as there is a want of balance between the porosity of the venous walls and the specific gravity of the blood contained therein; that is to say, when the venous walls become more porous, or the blood lighter and more aqueous than in the normal condition. In either ease there is an increased transudation of serum through the walls of the vessels. This is the manner in which local dropsy invariably occurs where individual veins are compressed, or, either for a time or permanently obstructed, as in cases of pressure from a tumour, or of complete obliteration. In this manner, the pressure of the impregnated uterus causes oedema of the feet; and pressure on the vena porta and vena cava ascendens, arising from degeneration of the liver, or some other tumour, produce ascites and oedema of the lower part of the body." Although the increased hydrostatic pressure of the blood is doubtless one of the determining causes of the effusion; yet, as the author observes, this phenomenon cannot, in the existing state of knowledge, be regarded as a purely mechanical process; nor does the above account explain all that takes place. How, for example, does it happen that the fibrin, which is dissolved in the plasma, remains in the vessels when the serum escapes; and, again, what is the reason why, as a general rule, these dropsical fluids contain as large an amount of salts, but more water and less albumen than * 66 Neubildungen; literally, new formations." 1847.] Fibrinous Dropsy. 433 the serum of the blood? No satisfactory explanation can at present be offered of these and similar phenomena; but it is most probable that they still depend upon some subtle chemical and physical conditions affecting the blood, and requiring only further and more successful investigation for their elucidation. In speaking of fibrinous dropsy, the author appears not to be acquainted with the received opinions of this and other countries; for he says it is a species that has hitherto been seldom described, that its signification has not been properly interpreted, and that it has never been correctly distinguished from serous dropsy. It is somewhat surprising to find a pathologist of Dr. Vogel's attainments making these extraordinary statements, which the daily experience of all our readers must directly contradict. What is here termed "fibrinous dropsy," is that familiar form of effusion, partly of fibrin and partly of serum, which so repeatedly takes place, most commonly into the different serous membranes, but frequently in other situations, as in the parenchyma of organs. That this form of effusion "has never hitherto been correctly distinguished from serous dropsy," is a most absurd assertion. No practitioner would confound the two affections together; indeed, we are inclined to doubt whether the generality of medical men, by regarding the effusion of fibrin as an inflammatory process and that of a serous fluid as the result of congestion, do not thereby establish the most important and valuable of all distinctions. The author gives only a more technical definition of the same thing in the following passage : "In serous dropsy, the causes of venous dilatation are frequently mechanical, and are, consequently, included in the department of pathological anatomy. Not so with fibrinous dropsy. Here the dilatation is dependant on dynamic causes, whose investigation would, of necessity, lead us far into the department of nervous pathology. I restrict myself, at present, to the mere statement that fibrinous dropsy is essentially dependant on the capillary system; that it is associated with, and for the most part arises from, a dilatation of those vessels, and a tension and attenuation of their walls."-P. 51. * * * This opinion, namely, that the capillaries are more especially the part of the vascular system concerned in fibrinous dropsy, is in all probability correct; for, although it is impossible to demonstrate the fact in the human body, the well-known phenomena connected with the dilatation of the capillary vessels, as determined by the microscopic examination of the lower animals, leave scarcely any room for doubt. But a similar difficulty to that noticed with respect to serous dropsy, where only the serum of the blood escapes, presents itself here :— "Since the serous, and also the fibrinous fluids, take their origin from the blood, and are produced by the permeation of its fluid constituents through the walls of the vessels, how is it that in some cases we have one, and in others, the other form of effusion? In the present state of our knowledge, this question cannot be satisfactorily answered; there is, however, every probability that it admits of this solution; namely, that serous dropsy, as we have already stated, owes its origin to a permeation of the fluid of the blood through the walls of the veins, while fibrinous dropsy arises from a similar permeation through the walls of the capillary system."-P. 50. In connexion with this point, it must be borne in mind, what the above passage leaves in some doubt, though the fact is elsewhere noticed, that in fibrinous dropsy it is the whole of the liquor sanguinis that is effused, although subsequently, the serum often being absorbed, the lymph alone is met with. The general chemical character of the effused matter is thus described: "In its chemical composition, this fluid is identical with the plasma of the blood; that is to say, with the blood independently of its corpuscles: it is serum or the fluid of serous dropsy, with dissolved fibrin. * The similarity of the fluid to the plasma of the blood occasionally extends even to their quantitative composition; usually, however, the dropsical fluid is the richer in water, and contains a less amount of organic constituents-albumen and fibrin. It is very seldom that this rule is reversed. In this point, therefore, there is the same relation as between the fluid of serous dropsy and the serum of the blood."-P. 47. It is well known that the chances of effecting an absorption of a fibrinous dropsy are much less than in the serous form of effusion. The probability of securing this important object is, however, remarkably dependant upon the situation and extent of the effusion, and, according to the author, upon the state in which the fibrin exists. As to this latter point, Dr. Vogel affirms that, as long as the fibrinous fluid is not coagulated, it may, like the serous fluid, be resorbed, partially or completely; and even, he thinks, with a greater facility, on account of there being no impediment to the activity of the venous system. "But if the fibrin be once coagulated, then the resorption can only extend to the serum ;" unless, indeed, it can be rendered fluid again by chemical remedies, such as iodine, which, "for the present, remain unanswered questions." We cannot agree in the whole of these statements. As to the greater facility of absorption of liquid fibrin, as compared with serum, this must be mainly a matter of surmise; and, recollecting the rapid disappearance of ordinary dropsies, which occasionally takes place under active treatment, it does not seem to be a likely occurrence. Then, again, the author speaks doubtingly of a firmly established fact in pathology, the possibility, namely, of coagulated fibrin being absorbed. In iritis this is constantly seen, and the same thing is known to take place in effusions of solid fibrin occurring in the parenchyma of organs, as in the lungs. Dr. Vogel notices an interesting fact, that when the dropsical fluid is enclosed in a sac of coagulated fibrin, and in a manner thus cut off from the absorbing vessels, be they veins or lymphatics, the resorption is a more tedious and difficult process. We have lately met with a most striking example of a multitude of cysts, varying in size from a hazel-nut to an orange, formed of effused and coagulated fibrin, and containing serous fluid. The case was originally one of extensive chronic peritonitis affecting almost every part of the serous membrane, which was uniformly indurated, in some places cutting like a scirrhous substance, and also much thickened. There had been during life intense and long-continued suffering, with a feeling as if the bowels were bound together, and at other times a painful tearing sensation was experienced. Recent and most extensive acute peritonitis had supervened, producing the changes above noticed, and causing great swelling of the abdomen with a mixed feeling, on examination of fluctuation and doughiness. Under the microscope, the im |