158 



JOHN N. LOWE 

 TABLE 2 



nitrate anion exerts an independent action or it may form nitrites 

 which are more active. 



In table 2 are shown the equivalent conductivities and degree 

 of dissociation of the sodium salts. 



The values were calculated in the same manner as those for 

 the potassium salts. Here, as in the potassium salts, the reac- 

 tion of the melanophores was correlated with the degree of 

 dissociation. 



There are two reactions of the melanophores which are char- 

 acteristic of the potassium salts: (1) a primary contraction, 

 (2) an expansion which is the sign of death or degeneration of 

 the cell. The cell wall breaks down and the pigment granules 

 escape into the surrounding tissues. The degree of the cytolysis 

 is directly proportional to the degree of dissociation of the salt. 

 In sodium salts we have two specific reactions: (1) the expansion 

 and maintenance of the expansion for a certain period of time, 

 (2) a slow contraction. The two reactions of sodium salts occur 

 in an inverse order to those of the potassium salts, where con- 

 traction is followed by a cytolytic expansion. The contraction 

 in sodium salts is not followed by a cytolytic expansion, but the 

 disintegration takes place directly from the contracted pigment 

 cell. This contraction in sodium salts is directly comparable 

 to the cytolytic expansion observed in potassium salts, for both 

 of these stages indicates the death of the pigment cell. 



A. P. Mathews ('06) suggested that it is the ionic potential 

 of the ions, and not the difference of voltage between the plate of 



