METHODS OF STUDYIXG FUXGI 



11 



atmosphere never directly causes a fungous disease. 

 Such diseases^ as already indicated, are produced by 

 minute plants, which never arise spontaneously, but 

 always from some spore, or other reproductive form of a 

 previously existing plant of the same species. But 

 w^eather conditions may be favorable to the rapid devel- 

 opment of tliese fungi, and so indirectly cause the 

 diseases. 



METHODS OP STUDTIXG Er^s^GI 



The successful study of the minute characteristics 

 of most fungous diseases requires the use of a compound 

 microscope. These, however, can be obtained for a 

 comparatively small amount, and will well repay the 

 investment in the wonders revealed. By the aid of some 

 such little book as Phin's ''How to Use the Microscope,'' 

 or Bausch's ^^Manipulation of the Microscope,'' almost 

 anyone can learn how to manipulate a microscope, and 

 can examine the microscopic characters of the various 

 fungi affecting crops. One desiring to undertake such 

 study would find the following books helpful : 



Bennett & Murray : Cryptogamic Botany. 



Burrill : Parasitic Fungi of Illinois. 



Plowright : British Uredinia^ and Ustilagini^e. 



Scribner : Fungous Diseases of the Grape and Other 

 Plants. 



Smith : Diseases of Field and Garden Crops. 

 Ward : Diseases of Plants. 



The bulletins of the United States DejDartment of 

 Agriculture, especially the Journal of Mycology, and of 

 the various experiment stations, will also prove very 

 useful. 



METHODS OF DISTRIBUTIO js' 



There are manyVays in which fungous diseases are 

 distributed, although the commonest one is by means of 



