NEOLAMARCK/ISM AO! 
Ocean. As respects climatic variation in birds, Pro- 
fessor Baird first took up the inquiry, which was 
greatly extended, with especial relation to the for- 
mation of local varieties, by Dr. J. A. Allen,* who 
was the first to ascertain by careful measurements, 
and by a study of the difference in plumage and 
pelage of individuals inhabiting distant portions of 
a common habitat, the variations due to climatic and 
local causes. 
** That varieties,’’ he says, “‘ may and do arise by 
the action of climatic influences, and pass on to 
become species; and that species become, in like 
manner, differentiated into genera, is abundantly 
indicated by the facts of geographical distribution, 
and the obvious relation of local forms to the con- 
ditions of environment. The present more or less 
unstable condition of the circumstances surrounding 
organic beings, together with the known mutations 
of climate our planet has undergone in past geologi- 
cal ages, point clearly to the agency of physical 
conditions as one of the chief factors in the evolu- 
tion of new forms of life. So long as the environing 
conditions remain stable, just so long will perma- 
nency of character be maintained; but let changes 
occur, however gradual or minute, and differentia- 
tions begin.’’ He inclines to regard the modifica- 
tions as due rather to the direct action of the con- 
ditions of environment than to “the round-about 
process of natural selection.’’ He also admits that 
*‘* The Influence of Physical Conditions in the Genesis of Spe- 
cies,” Radical Review, i., May, 1877. See also J. A. Allen in Bull. 
Mus. Comp. Zodl., ii., 1871; also R. Ridgway, American Journal of 
Science, December, 1872, January, 1873. 
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