TRANSUDATES AND EXUDATES. 353 



correspondence in the amount of salts and extractive bodies present in 

 the blood and in transudates supplies just as little proof for a filtration 

 as it does for the formation of lymph; but still it cannot be doubted for 

 other reasons that filtration is often of great importance in the forma- 

 tion of a transudate. To what extent filtration is active in the perfectly 

 normal vascular wall cannot be answered. 



The altered permeability of the capillary walls in disease is a second 

 important factor in the formation of transudates. The circumstance 

 that the greatest quantity of protein occurs in transudates in inflammatory 

 processes, to which is also due the abundant quantity of form-elements 

 in such transudates, has been explained by this hypothesis. The greater 

 quantity of protein in the transudates in formative irritation is in great 

 part explained by the large amount of destroyed form-elements. The 

 interesting observation made by PAUKULL, 1 that in those cases in which 

 an inflammatory irritation has taken place the fluid contains nucleoal- 

 bumin (or nucleoprotein?), while this substance does not occur in 

 transudates in the absence of inflammatory processes, can be explained 

 by the presence of form-elements. Still, such a phosphorized protein 

 substance does not occur in all inflammatory exudates. 



As the secretory importance of the capillary endothelium has been 

 made probable by the investigations of HEIDENHAIN, it is a priori to be 

 expected that an abnormally increased secretory activity of the endothe- 

 lium is a cause of transudates. Those observations which substantiate 

 such an assumption can also be explained just as well by assuming a 

 changed permeability of the capillary walls. 



The varying quantities of protein observed by C. SCHMIDT 2 in the 

 tissue-fluids in different vascular regions can perhaps be explained by the 

 different condition of the capillary endothelium. For example, the 

 amount of protein in the PERICARDIAL, PLEURAL, and PERITONEAL FLUIDS 

 is considerably greater than in those fluids which are found in the SUB- 

 ARACHNOIDAL SPACE, in the SUBCUTANEOUS TISSUES, or in the AQUEOUS 

 HUMOR, which are poor in protein. The condition of the blood also 

 greatly affects the transudates, for in hydrsemia the amount of protein in 

 the transudate is very small. With the increase in the age of a transudate, 

 of a hydrocele fluid for instance, the quantity of protein is increased, 

 probably by resorption of water, and indeed exceptional cases may occur 

 in which the amount of protein, without any previous hemorrhage, is 

 even greater than in the blood-serum. 



The proteins of transudates are chiefly seralbumin, serglobulin, and 

 a little fibrinogen. Proteoses and peptones do not occur, excepting 



1 See Maly's Jahresber., 22. 



2 Cited from Hoppe-Seyler, Physiol. Chem., 607. 



