556 R. A. SPAETH 



2 hours 45 minutes. Conditions were as follows: 



A. Both melanophores and xanthophores expanded — 

 melanophores slightly. 



B. No change detected. 



C. All chromatophores contracted. 



17 hours 30 minutes. A. Chromatophores completely disintegrated. 



B. Xanthophores partially contracted (?). Melanophores 

 contracted as before. 



C. Xanthophores contracted, melanophores about half ex- 

 panded but no sign of degeneration- 

 Single scales from B and C when transferred to a 0.1 M 

 NaCi solution showed complete expansion of the mel- 

 anophores after nine minutes. 



22 hours. Conditions were as above except that in B, the xanthophores 

 were distinctly more contracted than in C. 



24 hours. Single scales from B and C were again transferred to a 0.1 

 M NaCl solution. After twelve minutes the scale from 

 B showed widely expanded melanophores while those of 

 the scale from C were only partially expanded. This 

 difference was obvious after seven minutes immersion in 

 the NaCl. 



26 hours 45 minutes. The two remaining scales in B showed the mel- 

 anophores to be about half expanded. In one of the two 

 scales in C they were very much expanded — the other was 

 unchanged. 



41 hours. All the chromatophores in both B and C were degenerating. 



This same protective action of the NaCl is clearly seen with 

 other salts of potassium also. Thus: 



May 1, 1912 



Scales from an 8 cm. female were immersed in a 0.1 M NaCl solution. 



2 hours 30 minutes after beginning the experiment. 2 sets were trans- 



ferred to A, 4 cc, 0.1 M NaCl + 2 cc. 0.2 M KI, and 

 B, 6 cc. M. 0.066 KI respectively. The melanophores 

 of both sets'were contracted in approximately seven and 

 one-half minutes. The xanthophores of A expanded 

 when first immersed. 



3 hours. The xanthophores of A were obviously contracting. 



3 hours 20 minutes. All the chromatophores were expanding (degener- 



ating) in B. In A all were contracted at this time. 



4 hours. The scales in B showed the chromatophores to be badly dis- 



integrated. In A the xanthophores were contracted and 

 the melanophores half expanded but there was no sign of 

 degeneration. 



