76 Minnesota Plant Diseases. 



Just as with bacteria, so with fungi, white blood corpuscles 

 seem to form the garrison guarding against attacks. As soon 

 as the fungus threads enter the tissues, the corpuscles gather 

 around them and the battle begins. Moreover, the corpuscles 

 are often produced in extraordinary numbers in the vicinity of 

 the fungus attack. They may thus exclude air from the fun- 

 gus and so materially hamper its growth. Plants have no such 

 protection and hence suffer more. The fungus may sometimes 

 encrust itself with lime, as in lumpy jaw, perhaps protecting 

 itself in this manner from unfavorable conditions. 



