156 LUTHER BURBANK 



But there was one migration made by pre 

 historic man in which the pear, apparently, did 

 not accompany him. This was the final stage 

 of the eastward journey of our remote ancestor 

 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 pre- 

 historic 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 fore- 

 runners of the Indian to the new continent. 



The seeds of all orchard fruits germinate far 

 better if they have riot been too thoroughly dried 

 But the seed of the pear is peculiarly susceptible 

 to destruction through drying; and if the ances 

 tral pear had the same quality, which we need 

 not doubt, this fact may in itself have been in- 

 strumental in restricting the spread of a tree 

 which, when introduced in America in modern 

 times, proved thoroughly adapted to our soil and 

 climate. 



