11 



•to be in the expected dried up condition. 

 The change would thus seem to be confined 

 to activity in the feathers alone. 



In a brief summary of the principal points 

 already discussed in connection with my 

 bird we may conclude (1 ) that Aptosochrom- 

 atism in my Passerina cyanea occurred 

 beyond doubt, (2) that although present 

 with severe feather loss it does not follow 

 that the gain of color was directly responsi- 

 ble to it, as proved by careful examination 

 of the newly acquired feathers, and (3) that 

 although the feather loss was objectively 

 independent of the Aptosochromatic change, 

 it might subjectively be so, inasmuch as old 

 and imperfect feathers were renewed for 

 active and healthy ones, in which such a 

 color change subsequently occurred. 



The results quoted of Dr. Chadbourne 

 and Mr. Maynard appear to me to be con- 

 clusive in themselves and require no further 

 comment. Microscopically, the color change 

 was not of as much prominence as might 

 have been expected at first thought, but it 

 will be recollected that blue and violet 

 colored feathers depend, in a large measure, 

 for their efi'ects, upon involved objective 

 superstructures, which act in combination 

 with some underlying pigment or pigments. 

 These pigments produce chemical objective 

 effects, due to the absorption of all light 

 rays not depending upon the characteristic 

 color of the pigments. 



Chemically and microscopically, the 

 feathers of my Passerina Gyanea appeared 

 to contain two pigments, one, a diffused 

 non-granular tawny colored stain, the other, 

 a granular blackish substance. The yel- 

 lowish stain was confined to the transparent 

 sheath of the barbs and to the barbules, 

 while the granular matter varied in place- 

 ment with the color of the feathers. 



