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The third point in my theory is that weather and other un- 

 favorable conditions have weakened the vitality of the chestnut 

 in the eastern United States, and that the fungus has developed 

 into prominence because of this. The reasons I have for advocat- 

 ing this theory are as follows : 



(1). The chestnut blight came into prominence suddenly in 

 1904, just after the severe winter of 1903-4. From my own ob- 

 servation at that time and since, I know that this winter was un- 

 nsnally severe on fruit, and to a less extent on shade and forest 

 trees in Connecticut. I am corroborated in my views by the ob- 

 servations of Professor Stone, botanist of the Massachusetts Ex- 

 periment Station, who has made a specialty of the diseases and 

 injuries of shade and forest trees. Various experiment stations 

 and other publications show that the fruit trees in -New York, 

 Michigan and Ohio suffered from this, and possibly from subse- 

 quent cold winters. 



(2). Since 1907, speaking particularly for Connecticut, we 

 have had five summers with unusual periods of drought, culmi- 

 nating with that of last season, which lasted from June until 

 about the first of August. I know that these droughts have been 

 hard on forest and shade trees from their weakened condition 

 and from the unusual number that have died. Except in the 

 case of chestnuts, the death of these trees has been laid directly 

 to the drought, by many observers. I have given somewhat more 

 detailed accounts of these weather conditions in my previous re- 

 ports, and will not dwell further on them here. We have found 

 that chestnut trees on the south and southwest exposures, (and 

 on that side of the trees) where they have suffered most from 

 drought and winter injury, have sometimes developed severe out- 

 breaks of the blight, while the trees on the more protected north- 

 ern exposures in the same vicinity did not. 



(3). We have found cases of chestnut blight developing more 

 severely in woods suffering from fire injury than in surrounding 

 woods not so injured. It has been our almost universal experi- 

 ence that blight develops first and most severely in the easily in- 

 jured chestnut sprouts from one to ten years old, whose new 

 roots have not yet become thoroughly established, and last on the 



