232 COLLOIDS IN BIOLOGY AND MEDICINE 



of front limbs resembling that observed in human nurslings when 

 they are given too much salt. In TACHAU'S experiments it is note- 

 worthy that there was no increase in average amount of water in the 

 animal but the edema was the expression of abnormal distribution of 

 water. These observations lend some support to FISCHER'S theory. 

 FISCHER observed that when fibrin and gelatin swelled up they 

 accumulated salt from an acid table salt solution and, consequently, 

 he regarded the salt retention as resulting from the edema. 



When we consider the controversy concerning FISCHER'S theory of 

 edema, it is evident that as yet he has offered no experimental proof 

 for his hypothesis. Except in a few special instances his opponents 

 have likewise failed to show its invalidity since, in my opinion, their 

 experimental methods failed to produce a local accumulation of 

 acid in living organs as required by FISCHER'S theory. No matter 

 what value may be set on FISCHER'S theory in the future, it has been 

 of enduring service in that it has transferred the emphasis in the study 

 of edema from the circulation to the tissues; it is not hydrostatic 

 differences in pressure but chemical damage to the tissue which 

 occasions edema. 1 



Inflammation. 



Though healthy cells are impermeable for blood plasma, inflamed 

 tissue permits a selective passage of plasma elements. 



A. OSWALD * found that the frequency of passage stood in the fol- 

 lowing order: 



Albumin > Globulin (Euglobulin) > Pseudoglobulin > Fibrinogen. 



This occurs in an order inversely to their susceptibility to salting out 

 by salts and to the viscosity of the various solutions : the less viscous 

 a plasma element is, the more easily does it pass through the inflamed 

 tissue. Albumin alone may be found in an exudate, but never fibrin- 

 ogen without the simultaneous presence of albumin and globulin. 

 In the acute stages all kinds of albumins are found in the exudate, 

 whereas, with the lapse of time, fibrinogen and then globulins diminish. 

 The normal cell membrane evidently behaves like an impermeable 

 ultrafilter, which has become more permeable by reason of the in- 

 flammatory process. We do not know the factors which bring this 

 about. [The tissue may be "coagulated" allowing freer diffusion 

 because of larger diffusion paths, or they may be more dispersed and 

 accumulate more "water of swelling." Either condition would 

 explain some of the phenomena. Tr.] 



1 [The most recent discussion of the question by LAWRENCE J. HENDERSON and 

 MARTIN H. FISCHER is contained in the Journal of the Am. Chem. Society, 

 Vol. XL, No. 5 (May, 1918). Tr.] 



