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

investigations have been made by the above-named chemists. Lecanu also investigated the varieties which may be shewn in healthy urine, according to age and sex.

The quantity of urine passed in the 24 hours, and its colour, are frequently of importance. A diminished quantity of the urine passed in 24 hours is under circumstances a sign particularly of acute diseases; an excessive increase of the urine, if permanent, is oftentimes indicative of serious diseases. A dark-coloured, flaming or fiery red urine commonly indicates an inflammatory affection; a dark brown red is generally observed in typhus. But the urine may also be coloured blood-red or brown-red by bile-pigment, which is easily detected by its re-action with nitric acid; the latter constantly indicates an affection of the liver; a blood-red urine commonly contains blood; there is then for the most part found in it a sediment of blood-corpuscles, which are recognized with the microscope; but should a little blood be contained in the urine and this in a state of solution, it may be discovered by adding nitric acid, which occasions a precipitation of coagulated albumen coloured red by hæmatine. This bloody urine indicates a bleeding in the kidneys, bladder, urethra, or, in the case of women, of the uterus. Blood flowing from the urethra comes in drops. If the blood is discharged in masses after clear urine, it comes from the bladder, and in that case it often stops up the passage from the bladder by coagulation; if the blood is distributed through the urine, partly dissolved, and not in very large quantity, it comes from the kidneys; if it be dark, and mixed with mucus and pus, it owes its origin to an ulcer. The presence of stone-colic shews that the blood has been poured out during the descent of a renal calculus.

Blue urine has been observed, though not frequently; in the majority of cases it probably owes its origin to the use of certain medicines; black urine has likewise been observed; the connexion however is not yet known between the colouring matter and the morbid process; greenish urine indicates, according to Prout, an oxalic acid diathesis; sediments of oxalate of lime form, or mulberry calculi pass away; a urine, which is pale-coloured, and has a bias to green, frequently indicates the presence of albumen, which is readily detected by heating to boiling or by nitric acid. In this case the urine is not perfectly clear, but slightly opalescent; its quantity may be increased, diminished, or natural. The oxalic-acid diathesis of the urine indicates, according to Prout, functional disturbances in the chylopoietic system; albuminuria ordinarily indicates dropsy and an affection of the kidneys. The re-action of the urine is important for the physician. Natural urine, it is well known, has an acid re-action: the quantity of free acids in the urine and the intensity of the re-action may encrease to an extraordinary degree in diseases, more particularly in rheumatism, gout, in disturbances of the digestive organs, and in certain stages of typhus; to judge correctly of the intensity of the acid re-action, reference must be had to the quantity of the urine; the greater or less acid re-action is known by the effect of the urine on litmus paper of a weak blue colour, which becomes coloured so much the more rapidly and the more deeply reddened, the greater the acid contents of the urine are. Urine with a neutral re-action commonly forms the transition from the acid to the alkaline re-action, and vice versa. The alkaline

re-action of the urine is of great importance to the physician; it commonly depends on carbonate of ammonia, the presence of which is recognized by the odour, and the white cloud, which a glass-rod developes when moistened with an acid salt and brought near to it. The urine also may have an alkaline re-action through its containing carbonate of soda, which salt finds its way into the urine by the long-continued use of carbonate or bicarbonate of soda with vegetable acids. The urine alkaline by carbonate of ammonia is but seldom evacuated in this state from the bladder; during its discharge it is commonly neutral, and becomes alkaline only in a shorter or longer time after; badly-cleaned vessels may moreover contribute much to this, a circumstance which ought to be taken into account. Urine which already on voiding it has an ammoniacal re-action, and has also a very bad smell, indicates always a serious affection of the nervous system, and especially of the spinal cord. In certain unfavorable stages of tabes dorsalis, phthisis of the spinal cord, paralysis of the lower extremities and of the bladder, the voiding ammoniacal urine is ever an unfavourable sign; in other affections of the nervous system also, as in typhus, ammoniacal urine is observed, which however assumes this re-action in the majority of cases not till after it has stood for some time. In typhus the re-action of the urine may be of importance for the prognosis when the urine, after it was observed to have an acid re-action through one, two, or three periods of seven days, is finally found to be neutral, and then to have an ammoniacal odour and re-action; when this re-action lasts for several days, probably during one entire period of seven days, and then again passes into the acid, this seems in most cases to indicate a favorable termination to the disease. The urine having an ammoniacal re-action in typhus has usually a dirty, turbid yellow-brown or red-brown appearance, and forms sediments which disappear in a great measure on the addition of free acids; also in catarrhus vesicæ, or in phthisis vesicæ the urine becomes ammoniacal in a very short time after being voided; the large quantity of vesical mucus or pus indicates this affection; finally, the formation of urinary concretions, consisting of earthy phosphates, is in part occasioned by the neutral or alkaline re-action of the urine; the urine voided in this urinary affection, is not so dark as the urine in typhus, and commonly forms sediments of phosphate of lime, and of ammoniomagnesian phosphate. If the vesical calculus exercise an irritating influence on the parietes of the bladder, a great quantity of vesical mucus is commonly mixed with the urine.

The specific gravity of the urine, though by itself it possesses no great diagnostic value, as it depends on the variable quantity of water in the urine, may however claim the attention of the physician under certain circumstances; the clearer and the more like water the urine appears, the less is its specific gravity; the deeper and darker-coloured, the higher the specific gravity. This general law may admit an exception in one case, namely in diabetes mellitus; in this disease a urine is voided either normal or pale, seldom deeply coloured, the high specific gravity of which (1020-1060) is in contradiction to the colour; this high specific gravity imperatively requires a more strict examination of the urine. More than all other signs the correct examination of the sediments is of importance for the physician. Healthy urine forms only after long standing a light,

sinking cloud of vesical mucus; every other separation in the urine is of a pathological nature. The urinary sediment consists either of organic formations, as mucous corpuscles, purulent corpuscles, blood, &c. or of heavy, insoluble salts or acids, or lastly of an admixture of both; the microscope will throw light on this.

The sediment consists of organic formations. If the urine has not a blood-red colour, the sediment is white, grey, dirty-yellow, and with the microscope can be seen mucus, or pus-corpuscles; here the sediment is constantly mucus, if the urine contain no albumen; it is probably pus, if the sediment is deposited rapidly after the urine is voided, and the urine contains albumen. It is not necessary now to state of what importance it is to discover and appreciate mucus and pus in the urine; in catarrhus vesica the mucous sediment frequently assumes a very glutinous quality; this however happens only when the urine begins to become ammoniacal, which in urine containing mucus often occurs in a very short time, as we have already mentioned; the same may be said of pus, and it is good in this case to test the presence of albumen not by boiling heat, but by nitric acid. If the sediment is blood, the blood-corpuscles are then seen with the microscope; the urine standing over this is also of a bloodred colour. Of the import of blood in the urine I have no remark to make. If the urine contain albumen, and there exist at the bottom a mucous sediment, it is of great importance to examine this with the microscope. We may find therein, as I have observed, peculiar long prominences, partly filled, partly transparent, and round spheres, twice or thrice as large as mucous-corpuscles, filled with dark, granular contents, which beyond a doubt have their origin in the kidneys, and denote a morbid state of this organ. These peculiar forms I have frequently and at different times found in the urine of a person labouring under morbus Brightii.

The sediments which are not of an organic nature, may in like manner, be easily recognized with the microscope and some few re-agents; they are either crystalline or amorphous, present themselves either in acid, neutral or alkaline urine, and are readily distinguished; in acid urine sediments of uric acid present themselves, urate of ammonia, urate of soda, oxalate of lime, cystin. The greatest number of sediments which present themselves in acid urine consist of urate of ammonia; less frequent are, those consisting of uric acid, still rarer are those consisting of oxalate of lime, and the most uncommon of all are those consisting of cystin. Sediments consisting of earthy phosphates do not occur in urine having a strong acid re-action. Every sediment occurring in acid urine from yellow. to brown from red to purple red, appearing under the microscope as an amorphous precipitate, or as large and small globules aggregated together, which is dissolved entirely or almost entirely on warming the urine, is urate of ammonia; to this belong accordingly all the so-called critical separations in the urine; the species of separation of the urate of ammonia is very various, and it appears sometimes as mere turbidness, without forming any sediment whatever, sometimes it lies at the bottom of the vessel as coloured mucus or pus, at other times heavy, like an earthy precipitate. In the case of those diseases, which in the course of their development admit a termination by a critical separation in the urine, the kind of separation is of importance. The heavier the sediment lies at the bottom,