PROF. J. L. RUSSELL'S ADDRESS. 247 



zled and bewildered many a cultivator; yet the botanist has 

 unriddled the mystery. The minuter fungi are curious plants. 

 Their seeds or spores are of impalpable and imperceptible con- 

 sistence, except to the deepest powers of the microscope. They 

 are given out in myriads, and float in the air, and pervade the 

 soil ; so minute are they, that they are transmitted through the 

 sap-vessels and wait some favorable condition of the atmosphere 

 to develope them. This occurs when heat and dampness are 

 coincident : then the tissue swells and bursts ; the culm or 

 stalk opens outwardly; and a line of discoloration indicates the 

 hitherto insidious and invisible, but subtle foe. 



A discovery in one thing, points out a fact, or else leads to a 

 discovery, in another. Stalks of infested grain are unfit for any 

 thing but to burn ; nothing except fire can destroy the vitality 

 of these spores, and even of the seeds of some higher plants. 

 Fermentation in the compost-heap will not answer, and doubt- 

 less much of the succession of failure in crops from diseases of 

 the tissue, can be directly traced to the return of the disease to 

 the soil, in the form of manure, or by allowing the destroyed 

 stems to decay on the ground. 



And Nature teaches great lessons in other and more serious 

 ways. The total failure of crops induces famine and human 

 misery. The organic tissue of plants is as liable to disorder, as 

 is that of the animal kingdom. The valuable and almost indis- 

 pensable potato seems marked for more or less extensive ruin, 

 in the potato rot. This scourge is now pretty satisfactorily 

 proved to be a distinct and specific disease, having nothing to 

 do with the infesting of insects or of fungi. It belongs to the 

 kind of malady which attacks the sweet and delicious pear, and 

 turns it to gall and bitterness ; or which cankers the apple, and 

 converts it into insipidity, or something worse. It is a dry gan- 

 grene, a conversion of the parts of the tissue into a peculiar sub- 

 stance and consistence, not destroying the starch globules, nor 

 depriving the root of all its nutrition. Any remedy to be sought 

 in cultivation from renewed seed, or from new raising from the 

 balls or seed-vessels, will prove futile ; and probably a hope of 

 its cure will be found desperate. As an article of food, some 

 intelligent persons have long doubted its great or paramount 



