Fibrin

“ Pure fibrin occurs as long, white, elastic filaments, which are tasteless, inodorous, and insoluble in both hot and cold water. Wetted with acetic acid, it forms, after a time, a transparent jelly, which is slowly soluble in pure water. Very dilute solutions of the caustic alkalies dissolve it completely, and the new solution greatly resembles liquid albumen. Dried by a gentle heat it loses about 80% of water. ”

“ The fibrin is not an essential ingredient of the blood. All the functions of life are regularly performed in people whose blood lacks fibrin; and, in cases of transfusion, where blood deprived of its fibrin was used, the vivifying influence seemed to be the same. ”

“ The experimental study of the rate of fibrin formation, when different strengths of thrombin solutions are allowed to act upon a fibrinogen solution, leads us to the probable conclusion that the first of these three possibilities is the correct one, and that thrombin therefore exerts a true ferment action upon fibrinogen. It is known that in the reaction, in addition to the formation of fibrin, yet another protein makes its appearance. This is known as fibrinoglobulin, and apparently it arises from the fibrinogen, so that the change would be one of cleavage into fibrin and fibrinoglobulin. ”

“ Fibrin is a very sticky, stringy mass which forms a spongy network, spreads itself over the injury, and clings firmly to the edges, thus plugging the opening, unless the rush of blood is so strong that it keeps washing the fibrin away as fast as it is formed. ”

“ In the lean of meat, i.e. the muscles of the animal, we have the albuminous juices already described, the gelatinous membranes, sheaths, and walls of the muscle fibre, and the fibre itself. This is composed of muscle-fibrin, or syntonin, as Lehmann has named it. Living blood consists of a complex liquid, in which are suspended a multitude of minute cells, some red, others colourless. When the blood is removed and dies, it clots or partially solidifies, and is found to contain a network of extremely fine fibre, to which the name of fibrin is applied. ”

“ Fibrin not only covers the alveolar wall, but crosses this structure and often forms intracapillary plugs. In fact, besides the red blood cells, the serum and the fibrin, one often sees, not only an excess of polymorphonuclear leucocytes in the vessels of the lung, but these appear in process of migration within a few hours after the animal has been exposed.
Animals surviving this stage often succumb later with a typical pneumonic process. Although frequently pseudolobar, the process may be lobar in extent, and as time goes on more definite lobular involvement is frequently encountered. ”

“ After obliteration of the aneurismal cavity, the fibrin is generally deposited in so great quantity as to occupy the calibre of the vessel above and below the tumour, obstructing the progress of the blood, causing it to flow by the smaller and collateral branches, and effecting a spontaneous cure, somewhat similar to that produced by the artificial application of a ligature. ”

“ From this [Pg 241] organized fibrin spring innumerable little pointed cones, similar to the kernels of rice corn, at first of a pale red, becoming more florid as they increase in age, into which arteries and veins thrust themselves. These are the granulations. They have nerves and blood-vessels, are therefore alive, and when healthy, sensitive; and they likewise possess a disposition to unite, and when the two surfaces of a wound covered with granulations come in contact, the blood-vessels of one penetrate the other, they amalgamate and form flesh. ”

“ In a small number there is an abundant serous exudate, and with this there may be a considerable formation of fibrin, covering the surface of the membrane and floating in the fluid as flakes or masses; under the influence of movement it may assume the shape of melon-seed bodies. More rarely the joint contains pus, and the surface of the synovial membrane resembles the wall of a cold abscess. ”

“ He tells us that—
“Soon after salivation has been established, the blood exhibits an inflammatory crust; at a later period its colour deepens, and its coagulability is diminished; the proportion of clot, and, therefore, of fibrin, to serum (or watery part) becomes smaller; the formation of albumen and mucus sinks to that of serum; the whole organic formation of the patient is less consistent and cohesive.” ”

“ In very slow clotting at a low temperature the white corpuscles appear in a layer on top of the clot, the buffy coat.
Of fibrin little is known, but its formation is the most important step in clotting, as its presence is absolutely essential. If it is removed by whipping, the blood will not clot. It is a delicate, stringy material, elastic and contractile, and contains certain salts of lime and magnesium, upon whose presence its power of coagulation depends. The coagulability of blood differs in different people and is occasionally so little as to make operation dangerous. ”

“ The last step in the change is the action of thrombin upon fibrinogen to form fibrin, and the clot is complete.
The intrinsic value to the animal of these changes is quite plain. The power of clotting and thus stopping haemorrhage is of essential importance, and yet this clotting must not occur within the living blood-vessels, or it would speedily result in death. That the tissues should be able to accelerate the process is of very obvious value. That the inner lining of the blood-vessels does not act as a foreign tissue is possibly due to the extreme smoothness of their surface. ”

“ In the circumference of this focus, it is accelerated as formerly noticed: the blood is probably stagnated for two or three days in the capillaries and in the contiguous cellular tissue, when the action is at all violent. It,22 however, begins to move again; it loses its colouring matter, while stagnated; the fibrin is assimilated to the neighbouring parts, or rather effused, so as to cause the thickening, and the blood globules have possibly undergone a change, and been converted into those of pus. ”

“ The colliquation of the epithelium is produced by the action of an exudation rich in fibrin on the epithelial cells, which have suffered in their nutrition but which have maintained their connection with the cutis. The disturbance of nutrition is a combined result of the vascular lesion, the pressure of the exudation, and the resultant anæmia. ”

“ But as the years fall away and there is one less spring to flower and green, the serious man "tangled for the present in some parcels of fibrin, albumin, and phosphates" looks forward and backward and takes in both this world and the next. ”

“ Fibrin, produced from fibrinogen by a ferment, is a jelly-like substance, coagulable by heat, alcohol, &c. The muscle-albumins include “myosin” or paramyosinogen, a globulin, which by coagulation induces rigor mortis, and the closely related “myosinogen” or myogen; myoglobulin and myoalbumin are also found in muscles. The nucleo-albumins or phospho-globulins are insoluble in water and acids, but soluble in alkalies, and have an acid reaction. “Caseinogen” (after W. D. Halliburton) is the chief albumin of milk; its composition varies with the animal. ”

“ Under intense irritation the capillary walls will naturally be affected by the noxious agency as the veins of the sheep's foot were by the constricting cord, and, like them, will act upon their contained blood as if they were ordinary solids. The plasma of that blood will therefore receive from the blood-corpuscles the material requisite for forming fibrin, and, passing through the pores of the capillaries with that addition, will constitute a coagulable exudation. ”

“ After twenty-four hours it is taken from the soda lye, and after removing the free soda by washing, heated to 212° F, in a water-bath. The fibrin dissolves and becomes so thinly fluid that it can be filtered. 75 to 80 per cent. of the water is then evaporated, and the fibrin thus prepared can be used as a substitute for isinglass for fining purposes. Ichthyocolla swells more quickly in cold water than isinglass; 15 to 20 per cent. divided in water forms a thickly fluid substance, which on heating dissolves to a perfectly clear fluid. ”

“ In this fibrin are frequently found bacteria, even when there has been no recent acute inflammation. The deeper layers of the endocardium during acute inflammation may become infiltrated with young cells, with resultant softening and destruction of the intercellular substance. This softening and some swelling of the lower layers of the endocardium allow the pushing up of these extravasated blood cells which, being covered with fibrin, makes the little vegetations above described ”

“ And this goes on until you have left in the clot very little besides corpuscles entangled in a network of fibrin, and all the rest of the blood has been squeezed outside the clot, and is then called serum. Serum, then, is blood out of which the corpuscles have been strained by the process of clotting.
Now I dare say you are ready to ask the question, If blood clots so readily when it is shed, why does it not clot inside the body? Why is our blood ever{48} fluid? This is rather a difficult question to answer. When blood is shed from the warm body it soon gets cool. ”

“ If the coagulum be allowed to remain, the vein in which it is formed soon becomes thickened; but, as the experiments cited [Pg 4] prove, this thickening is the effect and not the cause of the stagnation of the vitiated blood in the vessel.
II. When blood coagulates in a serous cavity, a thin pellicle forms upon its surface, and, becoming thickened by deposition from the fibrin of the blood, forms a cyst, which completely circumscribes the effusion. ”

“ Albumen is without color, taste, or smell, and it coagulates by heat, acids, and alcohol.
Observation. The white of an egg is composed of albumen, which can be coagulated or hardened by alcohol. As albumen enters so largely into the composition of the brain, is not the impaired intellect and moral degradation of the inebriate attributable to the effect of alcohol in hardening the albumen of this organ?
59. Fibrin exists abundantly in the blood, chyle, and lymph. It constitutes the basis of the muscles. Fibrin is of a whitish color, inodorous, and insoluble in cold water. ”

“ The alterations in an inflamed tissue are first those of congestion, distention of the blood vessels, and exudation of the fluid of the blood into the surrounding fibers, with, however, a more nearly complete stagnation of the blood; fibrin, or lymph, a plastic substance, is thrown out as well, and the cells, which we have seen to be living organisms in themselves, no longer carried in the current of the blood, migrate from the vessels and, finding proper nutriment, proliferate or multiply with greater or lesser rapidity. ”

“ The constitutional conditions that produce the tendency to hemorrhage are most important. In individuals of a debilitated condition, it results from the lack of a proper amount of fibrin in the blood. Where the blood becomes thin, or loses a large share of its red corpuscles, the individual is pale, and hemorrhages are frequent from the mucous surfaces of any portion of the body, the nasal mucous surface being especially liable to such attacks. ”

“ In the early cases especially, or in cases which terminate fatally at an early period, both lungs are often involved, and, on histological examination, only a small portion of the pulmonary parenchyma is found unaffected. The exudate, largely acellular, presents serum as its most conspicuous feature. The picture is one of a patchy pneumonia with intermediary areas of what might be called edema, although fibrin is often demonstrable in the coagulated, albuminous material. ”

“ It is, however, the nitrogenous constituents of living tissues, that display most markedly those characteristics of which we have been tracing the growth. Albumen, fibrin, casein, and their allies, are bodies in which that molecular mobility exhibited by three of their components in so high a degree is reduced to a minimum. ”

“ As to its origin in the form of fibrinous deposit on the valves of the heart or a roughened spot on the aorta, we must refer to the article on General Pathology. The most important [p. 951] condition for embolism is disease of the valves of the heart, rheumatic or otherwise. Next comes arterial disease, producing roughening of the inner coat and subsequent deposition of fibrin. ”

“ The properties of fibrin, so far as cookery is concerned, place it between albumen and gelatin; it is coagulable like albumen, and soluble like gelatin, but in a minor degree. Like gelatin, it is tasteless and non-nutritious alone. This has been proved by feeding animals on lean meat, which has been cut up and subjected to the action of cold water, which dissolves out the albumen and other juices of the flesh, and leaves only the muscular fibre and its envelopes. ”

“ For the bones, it is phosphate of lime and gelatine; it is gelatine alone for the cartilages, tendons, &c.; fibrin for the muscles, albumen for certain other organs; so that if the nutritive parenchyma of a bone was filled with fibrin, it would be a muscle in the form of a bone, and vice versa, a muscle would become a bone with a muscular form, if its parenchyma was filled up with earthy and gelatinous substances. We should know the nature of all the living parts, if their nutritive substances were known to us ”

“ The coagulability of the blood is increased in diseases characterized by an excess of its fibrin-producing constituents, of which cirrhosis of the liver may be mentioned as one having this peculiarity. ”