crops by disease, losses which statistics show may amount 

 to tens of millions annually; and while the study of the 

 action of bacteria and fungi in the disease of plants is by 

 no means complete, no one can deny the practical results 

 which have been attained. In the more indefinite func- 

 tional diseases of plants not ascribable to definite parasites, 

 there is room for much more information, which will be 

 forthcoming when our knowledge of nutrition physiology 

 is more full. Already, however, we have suggestions as 

 to the cause of the functional diseases which often appear 

 where the same crop has been raised for many years in 

 succession in the same spot, which bid fair to explain some 

 important plant ailments that are at present not under- 

 stood. 



A more popularly interesting line of activity that has a 

 practical bearing is found in plant breeding, which has 

 recently been attracting wide attention. Plants are now 

 bred systematically for desired characters, not always 

 simply for increased yield, but also for such qualities as 

 resistance to extremes of temperature, to lack of moisture 

 in dry or semi-arid regions, to resistance towards specific 

 diseases, and even for the more esthetic qualities of flavor 

 or color. The old hit or miss methods of the improvement 

 of strains by empirical rules of selection is passing away, 

 and more and more scientific methods, based on the latest 

 results of investigations of heredity and variation, are 

 being employed. Passing over the older methods I will 

 take up two very different types of plant breeding, both 

 modern: one the strictly scientific, the other the intuitive. 



The first method we owe largely to Nilsson, who intro- 

 duced it at an experiment station in Sweden in connection 

 with the cultivation of various cereal crops. It may be 

 said that previous to his advent the older methods had 

 been tried and abandoned as a failure. With his knowl- 

 edge of what had been published about heredity and 



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