iQii] William J. Gies 281 



but because changes take place in them whereby they are enabied to 

 absorb water from any available source. In the case of the experiments 

 on toads and f rogs this available source of water is the water contained 

 in the dishes in which the animals are kept. In clinical cases of edema, 

 this is foiind in the fluids which pass through or about a tissue. 

 (Page 18.) 



As he proceeds in his book with the fortification of his theory 

 of edema, Fischer describes experiments on the swelling of fibrin 

 and gelatin in Solutions of acids and alkalies, and also in such 

 Solutions that contained or which were free from electrolytes or 

 non-electrolytes. The bloating effects of acid Solutions are especi- 

 ally emphasized and the counteracting influences of electrolytes are 

 noted. Thus, in discussing effects on fibrin he says (P...24) : "The 

 addition of any salt to the Solution of an acid or an alkali decreases 

 the amount that fibrin will swell in that Solution. . . . The higher 

 the concentration of the added salt, the less does the fibrin swell, 

 and if enough is added, the effect of the acid or alkali may be sup- 

 pressed entirely." Fischer alludes as follows to the significance 

 of these particular experimental findings : 



These differences and similarities in the behavior of diff erent colloids 

 toward the same external conditions demand detailed study, for they 

 are of the utmost biological importance. Protoplasm consists, as is well 

 known, of a mixture of many different colloids. Not only are different 

 colloids found in the same cell, but essentially different colloids form 

 the basis of different tissues (bone, cartilage, muscle, connective tissue, 

 parenchymatous organs, central nervous System). It is at once appar- 

 ent therefore, that not only so far as water absorption and secretion is 

 concerned, but so far as any physiological reaction dependent upon the 

 colloidal Constitution of living matter is concerned, a single Variation 

 in internal or external conditions may be followed by quite a different 

 response either qualitatively or quantitatively, not only by different 

 tissues but by different parts of the same tissue or even the same cell. 

 In a study of the behavior of different colloids toward the same group 

 of external conditions we may therefore hope to discover much to aid 

 US in our attempt to analyze the apparently limitless variations in the 

 reactions of protoplasm to various external " stimuH." (Page 55.) 



The foregoing paragraph is followed by this general Statement, 

 under the heading "The analogy between the swelling of certain 

 colloids and the swelling of protoplasm " : 



