PREFATORY NOTE. 



By E. a. BESSEY, M.A., Ph.D. 



That crops are subject to diseases of various 

 kinds, has been known for thousands of years. 

 In the Bible we find reference to mildews and 

 blasted crops, while among the Roman writers 

 a number of different diseases were recognized. 

 As early as the middle of the eighteenth century, 

 considerable study had been made of some of 

 the fungi which caused plant diseases, but even as 

 late as the third and fourth decade of the nine- 

 teenth century, there were some scientific agri- 

 culturists who insisted that the spots and dis- 

 colorations caused by fungi, or the spore masses of 

 these fungi, were but parts of the plant itself, while 

 even to the present day, some persons regard such; 

 epidemics as punishment or warnings sent by the: 

 Almighty to a sinful people. The brilliant re- 

 searches, however, of the great British and Ger- 

 man mycologists of the middle of the nineteenth 



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