LUTHER BURBANK 
that were pre-eminently desirable. First and fore- 
most it had fundamental vigor of constitution that 
promised to supply precisely what the European 
pear most lacked. This was manifested not only 
in the vigor of its growth, but in its seemingly al- 
most entire immunity to the attacks of the disease 
that has been the scourge of the pear growers of 
America for more than a century, and which made 
its appearance in California about ten years ago, 
the disease known as the pear blight. 
THE Pear TREE SCOURGE 
To appreciate the importance of this element 
of resistance to disease, as manifested by the ori- 
ental pear, it must be understood that the blight 
is a malady of such virulent nature that when it 
attacks the pear tree it very commonly results in 
killing it outright. This suggests, obviously, a pe- 
culiar susceptibility on the part of the pear. Such 
susceptibility is manifested, unfortunately, in ex- 
ceptional measure by the best European varieties, 
including the Flemish Beauty and the Bartlett. 
This, presumably, is the penalty of over-specializa- 
tion in a certain direction, or unbalanced selection. 
Until very recently the cause of pear blight was 
much disputed, but the agricultural experiment 
stations have now furnished conclusive proof that 
it is a bacterial disease, due to the presence of a 
germ that has been named Bacillus amolovorus. 
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