USES OF A RESEARCH MUSEUM 167 
sentation of specimens of the pure, native stock be properly preserved 
in our museums, for future comparison. 
I wish here to register an objection to the prevalent idea that ex- 
perimental methods upon the higher animals under artificially im- 
posed conditions may be expected to lead invariably to the satisfactory 
solution of evolutionary problems. I have in mind some experiments 
recently made upon birds. Certain species were kept captive in en- 
closures in which a relatively high atmospheric humidity was main- 
tained. The experimenter found that within the life of an individual, 
in fact within a few months, successive molts resulted in the plumages 
of some of the birds becoming darker. Feathers which were normally 
marked lightly with black became solid black. The increase of pig- 
ment throughout the plumage brought about a conspicuous change in 
the appearances of the birds, as great a difference as one finds between 
two near-related species under natural conditions, the one occupying 
an area of arid climate, the other a region of humidity. 
The conclusion from these few experiments, quite generally, but, I 
feel confident, too hastily, drawn, has been that there may be a “ direct 
influence ” of the atmospheric humidity sufficient to bring about the 
color characters of the different species as we find them under the 
varying natural conditions; in other words, that it is not a matter of 
gradual adaptive acquisition subject to inheritance. It is even being 
maintained widely among biologists that natural selection may have 
very little to do with the characters of animals as we find them in na- 
ture. 
I believe that the above experiments, among others carried on in 
the same way, will, alone, lead to inductions largely inapplicable to 
animals in the wild. My chief objection is that wild animals brought 
into confinement at once begin to show irregularities in various struc- 
tural respects. This is shown sufficiently by studies upon the skeletons 
of animals dying in zoological parks, a very large proportion of which 
are abnormally modified in various particulars. This diseased condi- 
tion undoubtedly begins just as soon as the animal is taken out of its 
natural surroundings. For the cessation of any one set of muscular 
activities is bound to bring about immediate changes in quantitative 
metabolism in the system. Change in food supply directly affects the 
entire organism, and unusual invasion by parasites ensues with con- 
comitant irregular growths. How then can we expect to get a knowl- 
edge of the processes of species formation under natural conditions 
from the extraordinary physical development or behavior of such 
animals ? 
I would urge that it is only through the close and long-continued 
study of animals in the wild state, that is, under perfectly natural 
conditions, that we can hope to gather conclusive evidence as to the 
