184 JOHN N. LOWE 



5. In the potassium salts, K2SO4, KCl, KBr, KNO3, and KI 

 there occurred a rapid contraction of the expanded melano- 

 phores. The rate and degree of the contraction was the order 

 given 



I> N03> Br> Cl> SO4 



This primary contraction was followed by a cytolytic de- 

 generation (expansion). The time required for the appearance 

 of this degeneration was greatest in 



I> N03> Br> Cl> SO4 



If the contraction or degeneration of the melanophores is 

 specific for the potassium cation, it is unqualifiedly modified by 

 its anion, or the residual part of the undissociated molecules. 



6. The neutral salts of sodium, Na2S04, NaCl, NaBr, NaNOa, 

 and Nal, caused a slow contraction of the melanophores. The 

 contraction was most rapid in Nal and slowest in Na2S04 and 

 other salts were intermediate as 



I> N03> Br> Cl> SO4 



Degeneration appeared first in Nal and last in Na2S04 and 

 varied in this order 



I> N03> Br> Cl> SO4 



The irritability of the chromatophores and life of the fish was 

 maintained longest in Na2S04 and NaCl from (118 to 132 hours) 

 in Nal from one to two and one-half hours. 



7. The pigment cells that were contracted in potassium salts, 

 when placed in sodium salt they expanded. The order of ex- 

 pansion was 



S04> Cl> Br> N03> I 



There was no expansion in Nal. 



8. The results obtained in the experiments on the action of 

 the salts on the pigment cells of trout are probable to be ex- 

 plained on one or more of three assumptions: (1) That it is due 

 to the antagonistic action between anion and cation; (2) that it 

 is the independent action of the cation; (3) that reaction of the 

 melanophores is likely modified by the undissociated molecule. 



