VI. DISEASES OF PLANTS. 
§ 302. 
PLants are, like all other organized bodies, sub- 
ject to a great many accidents and diseases. The 
most common causes are, improper soils, preterna- 
tural habitations, late frosts at night time, long con- 
tinued rain, great drought, violent storms, parasitic 
plants, insects and wounds of various kinds. 
Disease we call in plants that preternatural state 
by which their functions, or at least some of them, 
are disturbed, and the purposes for which they are 
destined annihilated. 
\ 
§ 308. 
& 
The diseases of plants are of different kinds; they 
attack either the whole plant, and are then called _ 
general diseases; or they only affect single parts, — 
when they get the name of local diseases. Sporadic 
we style those diseases, which of a great number of 
the same species of plants, only attack one or the 
other. Epidemic, on the contrary, when they in- 
vade a great number of plants, such as gangrene, 
necrosis, rubigo, and others. | 
§ 304. 
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