310 TRANSUDATIONS. 



faintly saline taste, of an alkaline reaction, and generally of lower 

 specific gravity than the serum of the corresponding blood. Their 

 morphological elements vary with the surfaces on which they are 

 effused; and hence we may meet with epithelial structures, mole- 

 cular granules, bodies resembling nuclei and cell-formations, which, 

 however, are not peculiar to transudations ; blood-corpuscles only 

 occur in them when the capillaries have become lacerated in con- 

 sequence of some disturbing influence, and blood has thus been 

 actually mixed with the transudation. 



Moreover, the chemical constituents of the transudations are 

 precisely 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 in- 

 creased ; and further, that some even of the organic constituents are 

 so subordinate, that they appear to be altogether wanting, and under 

 the specially existing conditions, 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 sub- 

 stance 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 albuminous and fibrinous ; or, if they are 

 very excessive, into serous and fibrinous dropsy (Jul. Vogel).* No 

 fibrin is to be found in the normal transudations of serous mem- 

 branes,, and in those excessive effusions which are not accompanied 

 by that affection of the capillaries which we 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 trans- 

 udation in non-fibrinous dropsy proceeds chiefly from the smaller 

 veins, and in fibrinous dropsy from the true capillaries, is a point 

 \vhich must be established by further histological investigations. 

 Some capillaries may, in their perfectly normal state, possess the 

 property of allowing the passage of a fibrinous transudation. If the 

 parenchymatous juice which has become effused for the nutrition 

 * Path. Anat. Th. 1, S. 12 35 [or English translation, pp. 3357.] 



