228 CULTURE OF THE GRAPE. 



but, wherever decomposition is going on, there mildew 

 will be found in some form or other. 



"The unhealthy exudation, from the surface of a leaf, 

 of this viscid matter, which dries, and no doubt decom- 

 poses, on exposure to the atmosphere, forms a proper food 

 for the mildew. The stomata, or pores of the leaf, being 

 stopped up, it is impossible that healthy respiration can 

 be resumed until the surface is perfectly cleansed. The 

 cause which produced the overflow, of sap (if I may so 

 term it) may have been transient ; but, as long as the 

 pores remain closed, it is impossible for the plant to grow 

 healthily. The tissue of the leaf or fruit becomes un- 

 healthy under such circumstances, merely from suffoca- 

 tion, as it were. The application of lime or sulphur 

 may cause the destruction of the fungus by acting 

 upon and purifying the viscid sap. Possibly, however, 

 the plentiful use of warm or even hot water, where it 

 can be used, might be quite as efficacious." 



I have quoted the communication of Mr. Jones nearly 

 entire, because it gives an interesting, and, I think, a cor- 

 rect view of the superinducing cause of mildew. Facts 

 will, however, compel us to differ from him in regarding 

 mildew as merely a " scavenger," &c. Were it of such 

 nature, we might regard mildew as a remedy for the pre- 



