PHYSIOLOGY OF CHROMATOPHORES OF FISHES 555 



9.56 P.M. Some melanophores were contracting in all six scales. 

 10.34 P.M. The control scales in 0.1 M NaCl showed widely expanded 

 melanophores. 



8.45 A.M. (June 14, 1912) All the melanophores in the mixture were 

 expanded but incompletely so. This was not the nor- 

 mal degeneration expansion of KSCN for the melano- 

 phores retained their contour and a scale brought into 

 0.1 M KCl showed a slight contraction in a few melan- 

 ophores. 

 In NaCl solutions the melanophores normally degenerate from the 

 contracted phase (p. 550). In the follomng experiment 

 the potassium is propotent at the beginning of the experi- 

 ment but the end effect is that of a sodium salt. 



June 13, 1912 



3.28 P.M. Scales from an 8 cm. female were placed in 0.1 M NaCl. 

 4.31 P.M. Scales were transferred to a solution of 8 cc. 0.5 M NaCl 



+ 2 cc. M KSCN. All the melanophores were contracted 



in three minutes. 

 10.34 P.M. These were unchanged. 

 9.00 A.M. (June 14, 1912) No change. At noon they showed iio 



response to a ten minute immersion in 1 per cent atropine 



sulphate solution. 



From this and the preceding experiment it is evident that the 

 addition of a certain amount of NaCI to a solution of a potas- 

 sium salt inhibits the normal degeneration (cytolysis) which has 

 been assumed to be the effect of the anion (p. 547). This action 

 of the NaCl is brought out even more strikingly in the following 

 experiment. 



May 1,1912 



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

 30 minutes after beginning the experiment. Three sets of four scales 

 each were transferred to, the following solutions. 



A. 2 cc. KBr 0.2 M + 4 cc. water. 



B. 2 cc. KBr 0.2 M + 2 cc. 0.1 M NaCl + 2 cc. water. 



C. 2 cc. KBr 0.2 M -f 4 cc. 0.1 M NaCl. 



(The concentration of the KBr is the same, 0.066 M, in all 

 three solutions). 

 45 minutes. All three solutions showed the xanthophores widely ex- 

 panded and the melanophores contracted ^vith a few 

 stumpy processes. All the scales were in the same con- 

 dition at this time. 



