By Thomas Andrew Knight, Esq. 85 



. wheat would probably afford seeds sufficient to communicate 

 disease to every acre of wheat in the British empire, under 

 circumstances favourable to the growth of the fungus : and I 

 have never seen a single acre of wheat, since the publication 

 of Sir Joseph Banks's pamphlet, so free from Mildew, but 

 that it would have afforded seeds enough amply to supply 

 the adjoining hundred acres. There is also reason to believe, 

 that the Berberry tree communicates this disease to wheat ; 

 and I have also often noticed a similar apparent parasitical 

 fungus upon the straws of the couch grass, in the hedges of 

 corn fields. 



Neither the Mildew of wheat, nor any other kind, can 

 however, I think, be communicated from the leaves and 

 stems of one plant immediately to those of another ; very 

 numerous attempts made by myself to succeed in experiments 

 of this kind having, I believe, proved wholly abortive; 

 though I once fancied that I had succeeded in two or three 

 instances. I am, therefore, much inclined to believe that 

 the parasitical fungus, which occasions every disease of this 

 kind, enters the plant, in the first instance, by its roots, 

 though it may probably be transferred with the graft, and 

 possibly by a bud, from one fruit tree to another : and if the 

 seeds be capable, like those of many other plants, of remain- 

 ing sound a considerable time beneath the soil, or in other 

 situations, till circumstances, which are favourable to their 

 growth, occur, the abundant appearance of the Mildew, or 

 mushrooms, may be accounted for without supposing them 

 to be generated wholly by the bodies from which they 

 immediately spring. 



I shall not trespass upon the time of the Horticultural 



