THEIR ANALYSIS. 331 



chapters in the first volume. We may, however, he permitted 

 to make the single remark that here, as indeed in every investiga- 

 tion of an animal fluid, the microscopical analysis must always 

 precede the chemical. Thus, for instance, the presence of blood- 

 corpuscles would at once destroy any claim that the fluid might 

 otherwise possess to the character of a pure transudation ; again, if 

 the object itself be not pure, the results of the experiment must 

 be in a corresponding degree worthless. The same observation 

 equally applies if vibriones and other formations which accompany 

 putrefaction are present. If none of these are to be observed, we 

 may frequently perceive cells in the transudation, which resemble 

 lymph-corpuscles or pus-cells. Without further investigation, they 

 have, however, no more claim to be considered as pus-corpuscles, 

 than those which are produced from mucous membranes ; it is only 

 when true pus is present (and in some cases it is very difficult to 

 decide this point) that the object should be regarded as not a 

 pure exudation. In transudations which contain no fibrin, the 

 substances in suspension, as for instance fat, epithelial cells, cells 

 in the process of development, and similar bodies, must naturally 

 be separated as far as is possible from the fluid by filtration; if, on 

 the other hand, coagulated fibrin be present, its absolute quantity 

 cannot be determined with accuracy; we must further ascertain by 

 microscopical investigations whether an excess or deficiency of 

 morphological elements be present, and we must obviously take this 

 circumstance into consideration in estimating the quantity of fibrin 

 contained in the transudation. 



The quantitative relations in which the various transudations, 

 either in the normal or excessive state, are thrown off from the 

 blood, are so various, that no general rule can be established even for 

 each individual capillary system. They become, however, of the 

 highest importance in relation both to the mechanical and the 

 chemical metamorphosis of matter in the healthy and the diseased 

 animal body ; but here the amount of the transudation is only of 

 interest in so far as the individual cases have reference to special 

 conditions, and may accordingly be applied to the establishment of 

 a more general view. 



As in the preceding pages we have already sufficiently noticed 

 the genesis of the transudation, in so far as we need here consider 

 the general metamorphosis of matter, it only further remains for 

 us to allude to the physiological value of the normal transudations, 

 and the uses of the abnormal ones as channels for pathological 

 processes (as after inwardly directed crises, &c.) ; but this is un- 



