FUNGOUS DISEASES. 



123 



this malady prompt measures should be taken to 

 prevent its spread and also to lessen the chance of 

 the permanent establishment of the germs in the 

 soil. In order to do this intelligently one should 

 understand how the disease spreads. 



Mode of Spread. — If the leaves of a vigorous 

 cabbage in moist soil be examined in the early morn- 

 ing tiny drops of water will often be found borne 



Fig. 27— Leaf in the Early Stages of the Rot 



upon the margin of the leaves, as seen at w in 

 Fig. 26. These water beads have exuded from the 

 interior of the leaf through the pores, which are 

 exceptionally large at these points. The germs most 

 commonly find entrance into the leaf by lodging in 

 one of these water beads and thence passing through 

 the pores into the veinlets, shown at v. In 

 addition, they are doubtless often introduced and 



