186 HOW TO GROW GOOD CORN. 



just as the wheat is bursting into ear, as smoke is 

 decidedly obnoxious to these small insects, which in 

 some seasons may be seen in thousands about the 

 bursting wheat. 



4 and 5. JJredo linearis ; JPnccinia graminis (Straw- 

 rust and Mildew). — "We refer to these epiphytes under 

 one heading, as there can be but little doubt that the 

 latter is a more advanced state of the former. They 

 both occur in oblong patches on the leaves and straw 

 of wheats and other grasses : in the uredo stage, of a 

 dull red colour ; in the puccinia stage, of a blackish 

 hue. They are both, as, indeed, are all these fungi, 

 interesting microscopic objects ; but our object now is 

 to describe them popularly. Both will always be found 

 in abundance in cold poor soils, and more especially 

 if the finer wheats be grown in such situations. The 

 application of a dressing of salt to the soil is said to 

 be a preventive. Be this as it may, the disease is 

 said to be rarer in Cheshire, where salt is so much 

 used by the farmer, than in any other county, in as 

 far as we have observed. 



Here, again, we incline to think that these are 

 morbid affections of the plant. They are, indeed, 

 viewed as such by Unger, in his " Die Exantheme 

 Pflanzen," in which the very title classes them with 

 eruptive diseases of animals. Berkeley and Henslow, 

 the two great authorities, however, do not accord 

 with this view : the former remarks in reference to 

 it — " Surely these plants are too distinctly, too regu- 

 larly, and too beautifully organized to be the products 

 of disease like warts or purulent matter in animals." 

 As, however, the microscope demonstrates that warts 

 and eruptive diseases have also their special and 



