LUTHER BURBANK 
accompany him. This was the final stage of the 
eastward journey of our remote ancestors which 
carried them across a land bridge, now no longer 
in existence, between northeastern Asia and the 
present Alaska, and thus brought them to 
America. 
It seems a fair presumption that when prehis- 
toric man made this final migration he brought 
the apple with him. 
At all events, with or without man’s aid, the 
apple made its way across the bridge that joined 
the continents. 
Probably the fact that the seeds of the pear 
will not germinate when once dried may explain 
the failure of that tree to come with the forerun- 
ners of the Indian to the new continent. 
The seeds of all orchard fruits germinate far 
better if they have not been too thoroughly dried. 
But the seed of the pear is peculiarly susceptible 
to destruction through drying; and if the ancestral 
pear had the same quality, which we need not 
doubt, this fact may in itself have been instru- 
mental in restricting the spread of a tree which, 
when introduced in America in modern times, 
proved thoroughly adapted to our soil and climate. 
We must not press this point too far, however, 
for the plum seed also dies if dried; yet the plum 
came to America in prehistoric times along with 
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