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CIVIC BIOLOGY 



home. They called it Providence and did not talk about 

 it. Again, modern commerce and travel are rapidly mixing 



FIG. 102. Tree (on the right) infected with peach yellows 



Peach yellows is a contagious disease, exterminative of the peach in northeastern 



United States, that has haffled all attempts to discover its cause. The tree shown 



on the right is in the last stages of the disease ; the one on the left is healthy 



the bacteria, fungi, and insects of all the world, and these are 

 the forces that have often determined both the floras and the 

 faunas of continents. More American Indians have been 



