I9I2] Martin H. Fischer 445 



If Gies grants that we agree on the fundamental importance o£ 

 the colloids and their State in determining the water content of 

 tissues, then a further difference of opinion can arise only in regard 

 to the mechanism by which the colloids are enabled to change their 

 water content under dififerent circumstances. But even here I 

 believe that Gies and I must easily find common ground. As the 

 condition in which abnormally great quantities of water are held by 

 the tissues — the edema of the pathologists — is of special interest to 

 medical men and as it is a subject which I have in consequence 

 treated in some detail, Gies has directed most of his criticism toward 

 the mechanism by which I maintain the increased hydration capacity 

 of the tissue colloids in the pathological states that are associated 

 with edema is brought about. 



My own conclusions regarding the nature and the cause of 

 edema have been summed up thus :^ 



A State of edema is induced whenever, in the presence of an ade- 

 quate supply of water, the affinity of the colloids of the tissues for 

 water is increased above that which we are pleased to call normal. The 

 accumulation of acids within the tissues brought about either through 

 their abnormal production, or through the inadequate removal of such 

 as some consider normally produced in the tissues, is chiefly responsible 

 for this increase in the afifinity of the colloids for water, though the 

 possibility of explaining at least some of the increased affinity for water 

 through the production or accumulation of substances which affect the 

 colloids in a way similar to acids or through the conversion of colloids 

 having but little affinity for water into such as have a greater affinity, 

 must also be borne in mind. 



To save space, I shall quote Gies'* directly and add my comment 

 in as few words as possible. 



Gies says : Lactic acid, in Fischer's view, is the responsible acid in 

 the production of edema. One is surprised, therefore, to find that 

 lactic acid does not figure in the summaries of Fischer's experimental 

 data. (Page 305.) 



'Martin H. Fischer: CEdema, p. gg. (New York, igio.) My earlier papers 

 stating the same conclusion have been and are constantly ignored. See my 

 Physiology of Alimentation, p. 268 (New York, 1907) ; Journal of the American 

 Medical Association, 51, 830 (igo8) ; Kolloidchemische Beihefte, i, g3 (igio). 



* William J. Gies: Biochemical Bulletin, i, 27g et seq. (igi2). All the page 

 references to Gies in the text are to this paper. 



