Licence: Public Domain Mark
Credit: Physiological chemistry (Volume 2). Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![similar to those of the blood-plasma; except that, as has been already noticed in regard to the lymph, all the constituents occur in a less ratio than in the plasma, and hence their water is increased ; and further, that some even of the organic constituents are so subordinate, that they ap- pear to be altogether wanting, and under the specially existing condi- tions, to be incapable of transudation. Hence we might classify the transudations according to the absence of one or other constituent of the plasma, if only we could draw any definite limit, and could exhibit the perfect absence of the substance in question even in special cases. The absence or presence of fibrin in the transudations has in this way occasioned the division of those effusions in the animal body which do not contain blood-cells into two principal classes, namely, into albumi- nous and fibrinous; or, if they are very excessive, into serous and fibri- nous dropsy (Jul. Vogel).1 No fibrin is to be found in the normal trans- udations of serous membranes, and in those excessive effusions which are not accompanied by that affection of the capillaries which wc assume to exist in inflammations; it is, therefore, absent in the cases of excessive accumulation of serum which arises either from a disturbed state of the functions of the lymphatics, or from an excess of water in the blood. If, however, the blood-current be much impeded, or if it be perfectly stopped in the capillaries, fibrin always escapes through the attenuated walls of the vessels, and gives rise to more or less plastic exudations. Whether, as Vogel assumes, the transudation in non-fibrinous dropsy proceeds chiefly from the smaller veins, and in fibrinous dropsy from the true capillaries, is a point which must be established by further histolo- logical investigations. Some capillaries may, in their perfectly normal state, possess the property of allowing the passage of fibrinous transuda- tion. If the parenchymatous juice which has become effused for the nu- trition of the organs cannot be readily isolated, and if we, consequently, are unable to prove, by a direct method, that it contains fibrin, yet, inde- pendently of the general belief, it is in the highest degree probable that this nutrient fluid actually contains fibrin; for this view is supported by the amount of fibrin occurring in lymph, by the constitution of the nutrient fluid in the lower animals which do not possess distinct blood- canals, and by the constant presence of fibrin in the ordinary plastic exudations, as is very well seen in the non-sanguinous secretion of fresh- incised wounds—a secretion which has been accurately analyzed by Schmidt.2 Fibrin may very often be contained in the transudations, when, from its small quantity, or from the metamorphoses which it has already undergone, it may evade chemical detection. If we consider that in the plasma of normal blood the quantity of fibrin is only one-fortieth of that of the albumen, and if we suppose that the diminution of the fibrin in the transudation only corresponds with that of the albumen, there could never be more than a very small, often almost inappreciable, quantity of fibrin in the effused fluid; if we further consider that the fibrin in the parenchymatous juices is very often applied to the renovation or repara- tion of tissues, and that in morbid transudations it soon commences to 1 Path. Anat. Th. 1. S. 12-35 [or English translation, pp. 33-57.] 2 Characteristic d. Cholera, S. 134.](https://iiif.wellcomecollection.org/image/b21136300_0036.jp2/full/800%2C/0/default.jpg)
