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1891.] The Origin of the Galapagos Islands. 315 
this process the process of harmonic growth, founded on the 
plasticity of the younger individuals. I believe that most of the 
variation goes on in certain definite directions produced by the 
conditions, this word taken in the widest sense. I do not believe 
that species originate through indefinite variation, produced by 
‘the mingling of different germ-plasmas on which natyral selec- 
tion works. I am inclined to: believe that any change must 
stimulate the organism, and I think it is this stimulus which 
affects the germ-plasma just as well as the somatic plasma, if we 
want to make any such artificial distinction. 
Perhaps we may be allowed to make some remarks in this con- 
nection about the inheritance of acquired characters. If any form 
shows a new character produced during the lifetime of the form, and 
not dependent upon any portion of the germ-plasma, we speak, in 
Weismann’s meaning, of an acquired character of this form. I 
may use a very clear example, taken from Darwin: “ The natives 
of the Amazonian region feed the common green parrot (Chrysotes 
festiva L.) with the fat of large Siluroid fishes, and the birds thus 
treated become beautifully variegated with red and yellow 
feathers. In the Malayan Archipelago the natives of Gilolo 
alter, in an analogous manner, the colors of another parrot, 
namely the Lorius garrulus L., and thus produce the Lori rajah 
or King Lory. These parrots in the Malay Islands and South 
America, when fed by the natives on natural vegetable food, such 
as rice and plantains, retain their proper colors.” 
Now here we have an acquired character. Will it be inherited? 
Certainly not, ifthe animal is fed with its natural food; but it will 
appear again when the animal receives the food producing the 
peculiar color. Another example: If an alpine plant is trans- 
ported to a botanical garden, and has become different from the 
alpine form, it has acquired a new character. The question is, Is 
this character “ inherited” by the next generation? The answer 
will be yes, if the conditions that produced this new character 
remain ; for instance, if we leave the plant in the botanical garden. 
The answer will be xo, if we change the conditions that pro- 
duced that new character; for instance, if we bring the plant back 
to its original locality. 
