326 TRANSUDATIONS. 



of the blood into acids and bases, and that they should allow only 

 of the transudation of the former ; in the simple transudations no 

 supplementary development of free acid appears, however, to 

 occur; it is only when suppuration and similar processes have 

 taken place in exudations that the fluid is observed to have an 

 acid reaction ; indeed, it is generally dependent on a process of 

 fermentation set up in the fat. 



Simon* once examined a specimen of the fluid of pemphigus 

 which had a strong acid reaction ; he considered the free acid to 

 be the acetic, in consequence of its apparent volatility ; this was 

 doubtless an uncommon condition ; the fat, in this case, as in 

 ordinary pus, may undergo butyric fermentation ; for all vesicular 

 cutaneous eruptions, whether they are produced artificially by 

 vesicants, or are the natural morbid phenomena of pemphigus, 

 herpes, or eczema, have an alkaline reaction, and contain albu- 

 men, as Andralf had formerly observed, and belong to the simple 

 transudations. It is only the vesicular cutaneous eruption, which is 

 known as sudamina, which invariably presents an acid reaction ; 

 it, however, does not arise, like the other vesicular eruptions, in 

 consequence of local congestion ; the fluid within the vesicles in 

 sudamina contains no albumen, and hence is not to be classed 

 amongst the transudations. We shall return to the causes of this 

 acid reaction when we treat of the sweat. 



HeintzJ has found a crystallizable organic acid, which sub- 

 limed without decomposition, and presented a very great similarity 

 to succinic acid in the fluid of cysts containing echinococci (see 

 vol. i., p. 74) ; as Dessaigne has proved that succinic acid may 

 be formed from butyric acid by oxidation, we need no longer 

 regard the occurrence of succinic acid in the animal organism as 

 extraordinary. 



It may be readily inferred from some of the preceding observa- 

 tions that the soluble mineral salts transude through the walls of 

 the capillaries in larger quantity than any organic matter ; but a 

 review of most of the good analyses of these exudations, in so far 

 as the subject has been yet investigated, leads us to regard the 

 following points as established : water in every case transudes in 

 the greatest quantity ; the fibrinous transudations which approxi- 

 mate most nearly to the plasma, in reference to their amount of 

 solid constituents, contain almost constantly rather less salts than 



* Med. Chem. Bd. 2, S. 579 [or English translation, vol. 2, p. 488]. 



t Compt. rend. T. 26, p. 650 657. 



Jenaische Ann. d. Physiol. u. Med. Bd. 1, S. 180191. 



Compt. rend. T. 30, p. 50. 



