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explained the effects of tonics; viz. by their constringing the extreme vessels of the relaxed parts? Some of them may produce their effects by acting as sedatives, as lead, cold. Their power of restraining hæmorrhage, may be attributed to their influence on the stomach and intestines being extended by sympathy to the more remote capillaries. We know the effect of chewing a mouthful of coarse common salt in the mouth, in arresting hæmoptysis; this will render it easy to conceive the possibility of such a sympathy. The efficacy of astringents is much more palpable, when they are applied locally; thus we see that astringent lotions act like charms in that relaxed state of the capillaries occurring after inflammation of the mucous membrane of the eye; and, after a gorged state of the capillaries of the alimentary canal from any cause, there can be little doubt that a passive state of dilatation may continue, after the cause of irritation has been removed, and that, under such circumstances, the use of an astringent medicine may force the relaxed and dilated vessels to resume their natural diameter. In this way the benefit derived from the preparations of steel in certain chronic derangements of the alimentary canal has been accounted for.

When the use of astringents seems to be indicated, it becomes necessary carefully to consider the cause of the morbidly excessive discharge, as such discharge may depend on diametrically opposite states of the system-we know hæmorrhage may be accompanied by plethora, or by real actual debility accompanied by inanition, and that the astringent to be applied will be toto cælo different-whilst the lancet and other depletory measures are to be employed in the former case, they are totally contraindicated in the latter. When the discharge depends on irritability, opium will prove the best astringent, or the salts of lead may be employed; in cases of diarrhoea, depending on the flow of acrid fluids into the intestines, by which their peristaltic action is increased, we may employ an astringent, properly so called, which will repress this discharge immediately and directly; or we may employ opium, which, though it may not arrest the discharge, may render the mucous surface insensible to its acridity; or we may, without either repressing the discharge or diminishing the sensibility of the mucous surface, obtund the acrimony of the discharge by giving an absorbent, such as magnesia.

It is in cases of hæmorrhages that the use of astringents is most important. Internal bleeding is now known, in almost every case, to depend on a relaxed state of the minute capillaries, which allows the blood to escape by a kind of exudation, no rupture of vessels whatever being present; and as this state may accompany congestion or relaxation, the hæmorrhage may be active or passive-in the former case astringents would be not only useless but injurious-hence the obvious necessity of carefully investigating the conditions of the system on which the hæmorrhage may depend.

[To be concluded in our next.]

BEITRAGE ZUR PHYSIOLOGISCHEN UND PATHOLOGISCHEN CHEMIE UND MIKROSKOPIE, IN IHRER ANWENDUNG AUF DIE PRAKTISCHE MEDIZIN UNTER MITWIRKUNG, &c. Herausgegeben von Dr. F. Simon. Band 1. Lieferung 1. Bogen 1-9. Berlin, 1843.

THIS is a new periodical, to be devoted exclusively to Chemistry and Microscopy, in their applications to Physiology and Pathology. The Editor is already favourably known to the public by his work on Medical Chemistry, as also by numerous contributions to pathological chemistry. It is our intention to extract from his Journal whatever may appear to us to possess sufficient interest for British readers. The introductory article, the professed object of which is to show what Chemistry has done for Practical Medicine, we have condensed on the present occasion. It contains the researches of the most eminent chemists into the composition of the principal fluids of the body, and the various changes and modifications produced in them by disease, and shews how far such modifications may be rendered available in practical medicine in establishing the Diagnosis, Prognosis, and Treatment of Disease.

THE BLOOD.

The physical characters of the blood are known to us ever since Leuenhoek's time; its chemical composition was not investigated till a later period. Dumas and Prevost made the first accurate chemical enquiries, especially into the constitution of the blood. Lecanu succeeded in

isolating the colouring matter of the blood first in combination with protein, and afterwards perfectly. Denis instituted numerous experiments on the chemical constitution of the blood, more especially with respect to the relative proportions in which the corpuscles of the blood exist therein, as compared with the fibrine, albumen, the salts, and the fat. Müller has shewn that the fibrine, albumen and globuline contained in the blood, consist chiefly of protein, and accordingly must be considered as slight modifications of one and the same organic substance; more recently still, Andral, Gavarret, and Simon have studied the different constitution of the blood in diseases; these chemical enquiries, combined with a correct appreciation of the physical state of the blood under various circumstances, have become important for diagnosis, and even for prognosis and treatment. Already the old physicians know how to deduce from the coagulation of the blood, from the quality of the coagulum and of the serum, conclusions respecting the process of disease, which they attained through experience, and the correctness of which was confirmed by continued attentive observations; the latest enquiries have taught us to become acquainted with those qualitative changes, and have shewn their connexion with the different chemical conditions of the blood, and this knowledge of

the different chemical conditions of the blood has yielded the most important contributions to semeiology through the medium of this fluid.

From the manner in which the coagulation of the blood takes place, when it is slow, but yet complete, in which case the blood has a higher temperature than in the healthy state, we may infer the existence of a phlogistic state; from an imperfect coagulation, when it does not amount to the formation of a perfect coagulum, but at most to the separation of gelatinous flocculi, a deficiency in fibrine is to be inferred. This then again indicates a high degree of debility and a depression of the vitality of the blood; this state of the blood is characterized as dissolution, though in most cases those parts which in the living blood are not dissolved, but are only floating, viz. the corpuscles of the blood, are observed to be in a state of perfect integrity.

From the quality of the coagulum we infer, when it is large and firm, a great quantity of fibrine, and at the same time a phlogistic state, more especially if the serum is clear and of a bright yellow, and the coagulum is covered with a solid inflammatory crust. But from a large solid coagulum we are not warranted in inferring a large quantity of blood-corpuscles, as in the generality of cases a diminution of the blood-corpuscles goes handin-hand with the increase of fibrine; accordingly a large solid body of blood, exclusive of the blood-corpuscles, must include a no inconsiderable quantity of blood-serum, for then the inflammatory crust itself is but a blood-serum inclosed in coagulated fibrine. A small solid coagulum indicates deficiency in the blood-corpuscles, there existing at the same time diminution, or at all events no increase of the fibrine, a state which is observed in chlorosis. A soft, dissolved, bilious like coagulum indicates great deficiency in fibrine, as observed when the vital powers are depressed, as, for instance, in the far advanced stage of typhus.

When the serum is very dark-coloured, we may infer that the redcolour of the blood is dissolved, or that the colouring matter of the bile is present; the former is ordinarily the case, when the blood contains an excess of water, or an excess or deficiency in the salts; in such cases also the quantity of the fibrine is extraordinarily diminished, and it belongs only to an imperfect formation of the coagulum; such a quality of the blood is observed in hydraemia, scurvy, and some species of bad typhus; the serum may be coloured blood-red by the colouring matter of the bile, and then, when decomposed with nitric acid, it yields the known changes of colour. In cases where the colouring matter of the bile is present in the serum, a large firm coagulum may form with an intensely coloured inflammatory crust, which indicates an inflammatory state, or the blood may coagulate only imperfectly, as in typhus icterodes. The presence of the colouring matter always indicates that the hepatic system sympathises. A whitish, turbid, milk-like serum is observed, when fat, pus, or fibrin, precipitated in very small kernels, visible only with the microscope, is made to float therein. The microscope shews which of these substances is present in the serum; if it be fat, the fat globules are seen; if pus, the pus-corpuscles; if fibrine, numberless small globules or points, which do not disappear on the addition of æther, nor on the addition of acetic acid, are deposited from the serum when diluted with water, and may be washed away with water. The presence of fat in the serum in

dicates not infrequently an organic change in the chylopoietic system, chiefly in the liver, as scirrhus of the liver. Pus in the serum indicates suppuration in the blood-vessels, phlebitis, or the presence of pus in the large organs, which assist in the circulation or preparation of the blood; at the very most minutely divided fibrine floating in the serum has been observed, and that but seldom. I found it but once in the blood of a man who laboured under Bright's disease of the kidney.

It is also of importance to take into our observations the form of the blood-corpuscles also; to be sure this seems to be essentially changed in but very few cases; several observers however agree in this, that in cases of severe typhus, where ammonia forms in the blood, the blood-corpuscles become changed, so that their edges appear torn and tattered.

The chemical investigation of the blood affords the most important points for establishing the diagnosis; it is evident that the correct appreciation of the signs, hitherto adduced from the physical qualities of the blood, was first obtained by physical examination; it gives us the only true solution regarding the quality and the change in the composition of this fluid; it has taught us that in inflammations the fibrine and fat become increased, and the blood-corpuscles diminished; that in chlorosis the blood-corpuscles are sometimes extraordinarily diminished, but the fibrine usually appears in its normal quantity; that in typhus the imperfect coagulation of the blood is to be ascribed to a deficiency in fibrine-matter; that in sea-scurvy an excess of salts is present; the chemical examination it is, which brings those physical signs from the blood already known to the ancients and correctly appreciated in reference to the mode of treatment into a peculiarly clear light. Experience and chemical examination have taught us, that in case of an increased reaction between the blood and oxygen the fibrine becomes increased and the blood-corpuscles diminished, and that in case of impeded re-action the quantity of fibrine becomes diminished. The results of experience also seem to lead us to think that a blood rich in fibrine increases the impulse of the heart, whereby the circulation becomes accelerated; when by abstracting blood the absolute quantity of fibrine is diminished, it appears that by this process also an impression is made on the heart's impulse, the consequence of which again is a smaller fibrination of the blood. Excessive venæsections may accordingly render the blood poor in fibrine, and thereby so change the re-action of the vascular system, that it becomes what is commonly designated a nervous re-action. From the blood and the re-action accordingly the physician must derive his indication, whether the venæsection is to be continued or not; if diminished re-action between the blood and oxygen diminishes the quantity of fibrine, it gives reason to think, that when phlogistic states exist under certain conditions, a reaction and a quality of blood may be found, which is more indicative of a nervous than of an inflammatory state. In case of inflammation of the respiratory organs, or of those inflammations which take on an extremely rapid and intense course, the physician sometimes finds a small oppressed pulse, which by itself alone, exclusive of the connexion with the other phenomena, would by no means call for venæsection; the blood drawn forms a soft, diffluent coagulum sometimes covered with a bilious-looking film, and it is only when, after a correct appreciation of the morbid process, the venesections

have been repeated, that the character of the inflammation shews itself in a manner not to be mistaken, as well in the quality of the blood as in the re-action. There is not a doubt that here, by excessive congestion in the lungs, or in the entire capillary system, the reciprocal action between oxygen and the blood was diminished, and it was only after the circulation again became free by the necessary abstraction of blood, those peculiar changes produced by inflammation showed themselves as well in the blood as in the re-action. With the other phenomena, which enable the physician to recognise chlorosis in the diseased body, it is the changed composition of the blood, ascertained by chemical examination, which is expressed in the great diminution of the blood-corpuscles; this examination will also teach him how far the preparations of iron must be continued, so that by the action of these remedies the composition of the blood may be again brought back to the normal state.

THE URINE.

From the physical and chemical state of the urine the attentive observing physician might obtain a great quantity of information for ascertaining and establishing a diagnosis; much of what might be said here is already known, and I shall touch on these points very superficially, much more however might prove to the reader not at all uninteresting.

The old physicians considered the examination of the urine as an important point for judging of diseases and of their probable course, and as we have already remarked, they made up for their deficiency in chemical knowledge by sharp and close observation: the earliest chemical examinations of the urine occurred in one of the earliest epochs of organic chemistry. Among the earlier investigators who paid attention to the urine, though very partially, I may mention Brandt, Kunkel, Boyle, Bellini; Boerhaave, however, attempted an analysis of the urine which, considering the time, was extremely good. Scheele's discovery of uric acid, and Cruikshanks' of urea, contributed essentially to a more correct knowledge of this secretion. The latter surgeon had already examined the urine in several diseases, especially in diabetes and dropsies. At the commencement of the present century it was chiefly Berzelius and Prout who made the urine the subject of extended enquiries; Berzelius demonstrated the existence of lactic acid, which by the earlier chemists had been considered to be acetic acid; the analysis communicated by Berzelius in 1809 of the composition of the urine, has been till within the last few years the only correct examination of the same; Prout has continued his inquiries up to the latest period. Of the more recent works on the constitution of the urine, those by Lecanu are the most prominent; within the last years Becquerel, Lehmann and Simon have employed themselves with examinations of the urine in the healthy and morbid state. Several constituents of the urine, both in the state of health and disease, are very accurately known, as uric acid, urea, lactic acid, the salts and the sugar of the urine; of others probably not less important we have a very imperfect knowledge, as of extractive and colouring matters. Regarding the quantitative composition of the urine, which is rather changeable, numerous

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