1908] Ward, Rapid Melanistic Change hi a Caged Rohin. 47 
have experimentally been greatly modified by subjecting the larva 
to abnormally high temperature. Recently Mr. C. W. Beebe at 
the gardens of the New York Zoological Society has carried on 
some important and significant experiments on the effects pro- 
duced on the colors of birds subjected to slightly supernormal 
temperature accompanied by increased humidity. In his "Sum- 
mary of the Effects of Humidity""^ on the Inca dove he states 
"'Intrinsically the change is at first a segregation and intensification 
of the melanism, resulting in a clearing up and extension of the 
white or whitish areas. A period of equilibrium later ensues,. until 
the increase of melanism is such that it begins to encroach upon 
the white areas, this continuing until all trace of white has disap- 
peared.'' 
In the Robins described by Barrows this sequence seems to 
have obtained : except that the one first reported became only in- 
completely melanistic while the second one as well as that de- 
scribed by Coues and our Milwaukee Robin have gone beyond this 
stage and developed a greater or less degree of albinism. 
Beebe* says farther : ''The sporadic appearance or artificial 
inducing of melanism in a single individual under humidity may 
be explained, and probably correctly, as merely the result of in- 
tensified action of the pigment-producing enzyme or unorganized 
ferment." Accepting this theory it is natural to suppose that a 
point will be reached when this abnormal production of melanisn 
will have exhausted the resources of the bird leaving it pigment- 
poor in which case albinism would succeed. 
1. Bull. Nuttall Ornithological Club, Vol. I, pp. 20-24; Vol. IV, 
pp. 27-30 ; Vol. V, pp. 25-30. 
2. Bull. Nuttall Omitholog-ical Club, Vol. I, p. 24. 
3. Bull. Xuttall Ornithological Club, Vol. Ill, p. 48. 
4. The Auk, Vol. I, p. 90. 
5. The Auk, Vol. II, p. 303. 
6. The Auk, Vol. Ill, p. 284. 
7. Zoologica, Vol. I, p. 30. 
8. Zoologica, Vol. 1, p. 34. 
