GELATINIZATION AND COAGULATION 299 



words minimal combining capacity and ionization of the jelly 

 is accompanied by minimal swelling capacity. 



Hofmeister has studied the effects of salts, acids and bases 

 upon the rate and magnitude of the sweUing which gelatin plates 

 undergo when immersed in their solutions; we have had occasion 

 to comment upon the significance and interpretation of his results 

 in Chap. VI. Wo. Ostwald (65) has investigated the influence 

 of the concentration of added salts upon the swelling of gelatin 

 plates in water. He asserts that the degree of swelling attained 

 after a given period does not vary continuously in a definite 

 sense as the concentration of the salt is increased, the curve 

 displaying the influence of the concentrations of the salt upon the 

 degree of swelling exhibiting very marked maxima and minima. 

 We shall have occasion to further dwell upon the significance 

 of these results in the next chapter. 



The phenomena which accompany and the processes which 

 underlie the taking up or loss of water by living tissues have been 

 investigated by Loeb (52) (53), Cooke (21), Bottazzi and Scalinci 

 (6), Beutner (3), and Korosy (47). Bottazzi and ScaHnci have 

 drawn attention to the remarkable fact, previously pointed out 

 by von Schroeder in the case of gelatin (93), that the crystalline 

 lens swells very markedly in distilled water or physiological 

 saline solution, but progressively loses water when suspended in 

 saturated water vapor at the same temperature. This phe- 

 nomenon undoubtedly involves a departure from the second law 

 of thermodynamics, realizing the possibility which was depicted 

 figuratively by " Maxwell's demon." It is not surprising, perhaps, 

 that the exception to the rule should have been first encountered 

 in the domain of colloid jelHes in which definite structures of 

 molecular dimensions play so pronounced a role in determining 

 their behavior. 



The significance of the phenomena of swelling in certain aspects 

 of clinical medicine has been especially insisted upon by M. H. 

 Fischer and discussed by him at length in his work upon oedema 

 (26) . Exception has, however, been taken by Moore to certain as- 

 pects of Fischer's interpretation of the phenomena of oedema (58). 



3. The Gelatinization and Coagulation of Proteins. — If an 

 insoluble gel, such a^ white of egg coagulated by fixatives, the 

 gel of collodion produced by the action of chloroform upon an 

 ether solution, common black india-rubber, or the hydrogel of 



