Among all the varieties of inflammation it is in acute rheumatism where we find the blood most decidedly loaded with fibrine. Owing to the powerful action of the heart and arteries, it is intensely arterial in character, and sometimes issues from the vein with a distinct pulsation.
those fevers which arise from marsh miasmata or from contagion, it is an opinion held by Dr. Stevens, and supported at great length in his work on the blood, that a diseased condition of that fluid is the first in the train of symptoms which occur, and the immediate cause of those which follow. The blood itself, says Dr. Stevens, is both black and diseased even before the attack. During the cold stage it is very dark. When first drawn it has a peculiar smell, and coagulates almost invariably without any crust. There are black spots on the surface of the crassamentum, the coagulum is so soft that it can easily be separated by the fingers, and during its forma tion a large quantity of the black colouring matter falls to the bottom of the cup. In the hot stage it becomes more red, and, in some cases, it is even florid for a time, but during the remission it is darker in colour than the blood of health, and decidedly diseased in all its properties. In milder cases, the blood which is drawn may coagulate without a crust on the surface ; but in the more severe forms of this fever, when the blood was drawn at an advanced period of the disease, a part of the albumen coagulated on the surface of the fibrine, and formed a diseased mass, which in appearance had a greater resemblance to oatmeal gruel than to blood drawn from a healthy person. The serum which separated was also diseased ; it had a brownish colour, and in some cases an oily appearance, which is never met with in the clear serum of healthy blood. In the climate or seasoning fever of the West Indies, which is not considered contagious, but a fever of excitement, the blood drawn in the first stage flows from the vein with great force, but is neither cupped nor buffed. It is so florid, being charged with salts which ought to have been removed by the organs of secretion, that it resembles arterial blood. The fibrine coagu lates firmly, and in some cases the serum which separates from it has a bright arterial colour, the colouring matter being not merely diffused through, but combined with the serum. During the progress of this kind of fever the blood loses a large proportion of its fibrine and albumen, and becomes so thin that it oozes from the mu cous membranes without any abrasion of sur face, and in the last stage turns quite black from a diminution in the proportion of its salts.
Such are the appearances which the blood presents in the more severe fevers of hot cli mates. In this country, at the commencement or stage of depression the blood is dark and tarry, coagulates quickly, and forms a large clot with but little serum. As the stage of excitement advances, the blood becomes thinner and more florid, and flows more freely. Coa gulation takes place more slowly, and a bully crust is frequently formed on the surface of the clot. In the latter stage, when the powers are giving way, the blood becomes thinner, darker, and more dissolved. It scarcely coa gulates at all, and is deficient in saline matter, and probably also in fibrine, thus nearly re sembling menstrual blood, or the fluid mixture of serum and red particles, already mentioned as often found in the larger vessels after death. Such are the alterations which the blood usually undergoes in the different stages of simple con tinued fever, but in its more malignant forms, as in typhus, the blood is generally very watery, even from the commencement. As the disease advances, it gradually loses its power of coagu lation, and in the last stage seems almost en tirely deprived of fibrine.
Magendie has artificially produced an analo gous state of blood by injecting putrid liquids into the veins of animals, and the speedily fatal disease which he thus caused had a strong ana logy with typhous fever.* To Dr. Stevens belongs the merit of having especially directed general attention to the cir cumstance that the saline matter of the blood gradually disappears in the progress of fever, and is almost entirely lost in its last stage. This he ascertained by direct experiment,t and his facts have since been confirmed by Jennings, who in the interesting report already alluded to, gives an analysis of the blood in six cases of continued fever, in which the alkaline salts were found diminished in the fol lowing proportions : In healthy serum, according to Lecanu, salts 8.10 In the serum of a male, aged first day of fever, salts 4 Ditto ditto aged 34, first day of fever, salts .. 5 Ditto female, aged 14, fourth day of fever, salts 4.2 Average of three other cases seems to be the universal opi nion of those who have seen and written on scurvy, that it owes its origin to a morbid change in the fluids, and especially in the blood; and even those who have been the most strenuous opposers of the humoral pathology in general, among the most celebrated of whom we may reckon Willis, Hoffmann, Boerhaave, Cullen, and Sir John Pringle, have made an exception in favour of this disease. Notwith standing this general belief there has been no attempt up to the present time at any chemical examination of the properties of scorbutic blood, and we have only the general obser vation made by the surgeons of Lord Anson's expedition, (Messrs. Ettrick and Allen,) that in
the beginning of the disease it flows from the arm in different shades of light and dark streaks; that as this advances, it runs thin and black, and after standing turns thick and of a dark muddy colour, the surface in many places being of a greenish hue, without any regular separation of its parts ; that in the third de gree of the disease it is as black as ink, and though kept stirring in the vessel for many hours, its fibrous parts have only the appear ance of wool or hair floating in a muddy sub stance; and that in dissected bodies the blood in the veins is so fluid that by cutting any con siderable branch, the part to which it belongs may be emptied of its black and yellow liquor, the extravasated blood being precisely of the same kind. The prevalence of scurvy where there has been a long-continued use of salted provisions has given rise to the supposition* that the salt itself actually finds its way into the circulation, and acts as it is known to act on blood out of the body by preventing its coagulation. This, however, is very evidently not the case, first, because salt provisions are not necessary to its production, since scurvy has often made its appearance where no salt provisions were used; as, for instance, in the Milbank Penitentiary in 181 9, where the diet consisted of pease, barley soup, and brown bread ; and, secondly, because the appearance of the blood, especially as the disease ad vances, is exactly the reverse of what it would be on the addition of salt, which, instead of making it black, and causing it on standing to become thick, muddy, and of a greenish hue, would impart to it a fine scarlet tint that would remain permanent until it began to putrefy. Since the modern advances in ani mal chemistry, opportunities for examining the blood in true scurvy have been very rare; and it is therefore the more to be regretted that Drs. Latham and Roget, philosophers every way so competent to determine the precise morbid changes which it undergoes, did not, when they had it in their power, make a particular ex amination of it. Venesection, it seems, was practised at the Penitentiary in a few cases, but nothing is stated respecting the appearance which the blood assumed.* The description of Lord Anson's surgeons does not by any means apply to the blood which is found in purpura hmorrhagica, a complaint that was, prior to the appearance of Dr. Bateman's work on diseases of the skin, generally considered closely allied to scurvy. In two cases of pur pura related by Dr. Parry,t of Bath, blood drawn from the arm exhibited a tenacious contracted coagulum covered with a thick coat of lymph ; and in one instance which occurred under my care, where the patient, a man of forty-five years of age, had most of the sym ptoms of sea-scurvy, such as general cachexia, with anasarca of the lower limbs, great depres sion of spirits and prostration of strength, ex tensive ecchymosis on the trunk and the ex tremities, fetid breath and extravasations of blood from the gums, the stomach, and the bowels, as well as from a large foul ulcer on the leg; a copious venesection demonstrated that the blood had not in any degree lost its crasis, the crassamentum being covered with a thick bully coat, and having as much firmness as is usual under the existence of such a state. It is proper to observe that Lind's description of the blood in scurvy differs from that of Lord Anson's surgeons, as lie found it generally either natural or buffed.I Jaundice. — In jaundice the blood, both arterial and venous, is tinged with bile, and this is apparent not only in the serum, but still more strikingly in the crassamentum, provided it be covered with a buffed surface. If this be removed and dried in a state of tension, it exhibits a deep yellow hue, particularly when viewed by transmitted light. Although the bile is thus rendered very visible in jaundiced blood, yet, owing to its combination with albumen, which defends it from the action of acids, it is difficult of de tection by chemical re-agents, so that many chemists of eminence have sought in vain to ascertain its presence. Lassaigne, however, succeeded in demonstrating that the colouring matter of the bile is really to be found in the circulation, and Berzelius tells us that Collard and Martigny pretend to have discovered even the resin of bile in jaundiced blood. M. Le canu has more recently confirmed these facts, and Mr. Kane has verified his results.§ To the medical inquirer who does not follow the "minutiae of animal chemistry, the identity of the colouring matter in the serum of jaundiced blood with that of the bile itself will be ren dered sufficiently evident by adding to it an equal quantity of sulphuric acid diluted with twice its bulk of water. The serum will thus change its yellow hue for the characteristic green colour of acid bile. Experimentalists have failed in producing this effect, being pro bably misled by having found that the small proportion of acid which is required to strike a green colour with urine charged with bile, produces no such effect when added to jaun diced serum.