84 On the Prevention of Mildew. 



numerous to account, to a great extent, for the ubiquity of 

 the plants they are supposed to produce, particularly as such 

 apparent seeds, owing to their excessive lightness, are capable 

 of being every where dispersed by winds. 



A few years ago I raised some mushrooms under glass 

 with the intention of collecting and subsequently raising 

 mushrooms from the seeds they might produce ; and I then 

 endeavoured to ascertain the number which would be afforded 

 by a single fructification ; for a mushroom appears to be 

 nothing more than a fructification of the plant, though it is 

 generally spoken of as the plant itself. I placed thin plates 

 of talc under a very large mushroom at the period when the 

 minute globular bodies, which are supposed to be the seeds, 

 first began to be disengaged from its gills ; and I endeavoured 

 to count the number which fell during each successive hour, 

 within the narrow field of a very powerful lens. The labour 

 to my eyes was, however, so severe, that I was unable to 

 count with any considerable degree of accuracy; but the 

 number, which fell from a single mushroom, within the suc- 

 ceeding ninety-six hours, exceeded, upon the lowest calcula- 

 tion I could make, two hundred and fifty millions. I endea- 

 voured to raise mushrooms from these seeds, but I failed to 

 obtain any decisive results ; for though I readily procured 

 mushroom spawn by mixing such seeds with unfermented 

 horse-dung, I also obtained it in equal abundance in some 

 instances, where I had not introduced any seeds. 



Immense as the number of seeds produced by a single 

 mushroom appears, it probably is not much greater than 

 that which a single plant of mildewed wheat would afford ; 

 and, according to this calculation, a single acre of mildewed 



