COMI'OS/'noX OF EDKMATOl s j'l.iins 

 Table II 



353 



Tlie specific g-ravity varies nearly in direct proportion to the amount 

 of proteins, that of traiisndates nsnally being below 1.015, and exu- 

 dates above 1.018, although there are many exceptions. Indeed, it is 

 often very difficult to decide whether a given fluid is an exudate 

 or a transudate.^'' According to Rzentkowski,*" the transudates at 

 the moment they pass out of the vessels are simply solutions of crystal- 

 loids in water and quite free from protein ; the small amount of protein 

 found in transudates he ascribes to protein pre-existing in the tissue- 

 spaces. This idea is hardly acceptable in view of the known per- 

 meability' of the vessel-walls for proteins in normal conditions ; more 

 probably in cardiac and renal dropsies the quantity of protein escap- 

 ing from the vessels is not greatly different from normal, but the 

 excessive fluid escaping in these conditions carries with it no addi- 

 tional proteins, and to this extent transudates in statu nascendi are 

 protein-free. 



Transudates, even when produced by the same cause, vary in com- 

 position in different parts of the body, presumably because of varia- 

 tions in the permeability of the vessels in different vascular areas; just 

 as pleural, pericardial, peritoneal, and meningeal fluids normally 

 differ from one another. Thus C. S. Schmidt *' found the composition 



4s Rivalta (Eif. Med., 1903: Bioehem. Centr., 1904 (2), 529) has siiirtrested 

 the following test to distinguish exudates and transudates: Into a beaker con- 

 taining 200 o.c. of water with 4 drops of glacial acetic acid, let fall a few drojjs 

 of the fluid to be tested. If an exudate, a bluish-white line is left transiently 

 behind the sinking drops, due to precipitation of the euglobulin and filjrinoyen. 

 Tliis test, and also certain modifications (see Rivalta. Policlinico, 1910 (17). 

 (i7fl), seem to give quite reliable results. (See I'jihard, Berl. klin. Woch., 1914 

 (51), 1112. With tuberculous effusions Rivalta's test is positive, but not Mo- 

 relli's test, which consists in dropping tlie fluid into saturated HgClo solution, a 

 yellowisii ring of all)uminate forming with non-tuber:'ulous exudates, and a gran- 

 ular precipitate with transudates. (See Zannini, Gaz. degli Osped., 1914 (4), 

 461). ]\Iemnii (Clin. Med. Ital., 1905, No. 3) suggests the larfrer content of 

 lipase as a means of distinction of exudates. Tedeschi (Caz. degli Osped.. 1905 

 (26), SS) states that e<jg-albumen fed in large amounts appears in transudates 

 and not in exudates, and can be detected by the biological precipitin test. Sugar 

 is found more often in transudates (Sittig). 



^o Virchow's Arch., 1905 (179), 405. 



47 Hoppe-Sevler's Phvsiol. Chemie. 

 23 



