THE DISEASES OF PLANTS. 307 



Caroline. This malady, far from disfiguring the plant, 

 adds to its beauty ; but who would ever have imagined 

 these colors to have proceeded from a separate vegetation 

 growing on the leaf? 



Mrs. B. Smut is a fungus, under the form of a black 

 powder, which lodges itself on the surface of the ears of 

 corn, particularly of oats. But the most insidious enemy 

 of grain, of the mushroom tribe, is called the Rot. It de- 

 vours the seed, without making its appearance externally. 

 When the corn is thrashed, the rotten seeds burst, and 

 the disease is thus communicated to the rest of the corn ; 

 so that if sown, the rot will be propagated as well as the 

 corn ; to prevent which, corn that is at all affected with 

 this disease should be soaked in a lime wash, which de- 

 stroys the seed of the rot, without injuring that of the 

 corn. 



Mr. Benedict Prevost has found that washes of vitriol 

 or verdigris, are still more efficacious. 



Emily. But are they not pernicious to the grain, and 

 even dangerous to those who employ them ? 



Mrs. B. It was at first apprehended to be so, but it is 

 now well ascertained, that neither the laborer nor the grain 

 suffer from this process : it is much used in France, and 

 even arsenic has been tried with success for this purpose. 



The Ergot is a disease peculiar to rye, which attacks 

 the ovary of that plant; and bread made of rye thus affected 

 is extremely unwholesome, frequently producing gangrene. 



It would be endless to detail the various fungi which 

 molest the vegetable kingdom; we will conclude, there- 

 fore, with the Rust, which confines its depredations to the 

 grasses. 



It is time now to turn our attention to the last class of 

 diseases, those resulting from age ; and here you must 

 observe that a very essential difference exists between the 

 animal and the vegetable creation. In the former, all the 

 organs are developed at once: these after long use become 

 indurated, obstructions take place, decay follows, and life 

 thus often terminates from old age. But the economy of 

 the vegetable kingdom is totally different : the organs of 



1657. What is said of the smut! 1658. And of the rot and its 

 effects'? 1659. How may it be prevented! 1660. Are not these 

 antidotes injurious to the corn and to the persons who use them! 1661. 

 What is said of the Ergot, and the Rust! 1662. So far as disease 

 results from age what comparison is made between animals and vegetables! 



