3 28 ALLEN, ‘ Aptosochromatism.’ aur 
showing loss of feathers from Nov. 1 to Feb. 11, and adds that 
from Feb. 11 to Feb. 28 “ an average of 50 contour feathers was 
lost daily,” and that “the loss had abruptly ceased’ by March 5. 
(The bird died March 29.) The total loss of contour feathers 
was estimated at 1350, or about three-fifths of the bird’s entire 
plumage. Hesays: ‘‘To many observers my bird by March sth 
would have been pronounced to be completely moulting.” This 
feather loss he does not consider as normal, but as resulting indi. 
rectly from the bird’s timid, fretful temperament, many of his 
feathers becoming more or less injured by his “ wild fluttering ” in 
the cage, and consequently shed, as, ‘when such a vital pro- 
cess as Aptosochromatism [with a big A] begins to work, these 
decrepit feathers necessarily would have to be renewed in order 
to take part in the general plan.... It will be noticed in the 
table how gradually the loss began, due doubtless to the gradual 
approach of activity towards color change in the feathers. It 
must be admitted that this explanation is purely hypothetical, but 
such a hypothesis, although not of fundamental importance, oft- 
times prepares the way for a clearer understanding of the problem 
under consideration.” 
‘‘ The first appearances of color change,’’ he says, “ were noticed 
in some of the old feathers of the crown during the first week in 
February,” when ‘‘a brightening of the blue area of the feather 
was noticed, but no perceptible change of color at the tips where 
the TUSSet Was... . When the band of tawny was reached, it 
appeared to be slowly absorbed until but faint tips of this color 
could be seen upon the ends of the larger barbs. In no cases 
were the barbs or barbules broken off sufficiently to account for 
the change.” After describing the general course and character 
of the color change over the body Mr. Birtwell sums up as fol- 
lows: “ While my bird threw out no hint whatever as to the con- 
stant occurrence of the color change, it did prove that the ‘ impos- 
sibility’? is possible. It is certain that the heavy feather loss of 
my bird but indirectly helped the change: rst, we have seen that 
many feathers changed which were not renewed by moult; 2d, we 
saw that those feathers which were renewed by direct gain and loss 
were colored similarly to those which preceded them, but that later 
on they changed Aptosochromatically, and 3d, no purely blue, z.¢., 
