538 R. A. SPAETH 



2. Further dilution of the sea-water (from 1 part sea-water: 

 3 distilled water to 1 part sea-water: 14 distilled water) produced 

 a prolonged expansion. 



3. The duration of this expansion decreased with still greater 

 dilution (1 part sea-water: 25 distilled water) and at a con- 

 centration of 1 part sea: 50 distilled water the presence of the 

 sea- water could only be detected by its protective action; Vie mel- 

 anophores of scales in the mixture remained irritable longer than 

 those of the control scales in distilled water. 



August 23, 1912 



10.24 A.M. Scales from an 8.5 cm. female immersed in 8 cc. of 3 parts 

 sea-: 1 of distilled water and 8 cc. sea-water respectively. 

 The fish was not previously rinsed in distilled water in 

 this case. 



11.20 A.M. No differences in the two sets. 



12.10 A.M. The set in sea-water is distinctly more yellow to the naked 



eye and shows (under the microscope) the xanthophores 

 more expanded than those in the mixture. 

 12.15 P.M. The scales in the mixture appear slightly darker, with their 

 melanophores more expanded than those in the sea-water : 

 the xanthophores are contracted. This mixture is thus 

 a solution which, after two hours, acts oppositely upon the 

 two sets of chromatophores — -expanding the melanophores 

 and contracting the xanthopores. 

 8.40 P.M. Degeneration. Difference in the xanthophores as above. 

 T. = 25.5°C. 



At the following and greater dilutions, control scales were run 

 in distilled water rather than sea-water. In this experunent the 

 melanophores in the mixture remain expanded nearly an hour 

 after those in the distilled water have degenerated. 



August 22, 1912 



10.58 A.M. Scales from an 8 cm. female were removed to 8 cc. distilled 

 water and 8 cc. of 1 part sea-: 14 distilled water, 



11.02 A.M. All melanophores were expanding in the mixture while the 

 scales in distilled water were lighter with many peripheral 

 melanophores contracting. 



11.08 A.M. All the melanophores in the distilled water set were con- 

 tracted. All in the mixture were still widely expanded. 



11.11 A.M. Majority in distilled water showed the secondary expansion 



(relaxation from spheriform phase). 



