144 ERTSIPHE. 



off and vegetate on the plant. Abundant spe- 

 cimens may be frequently seen on the leaves of 

 peach-trees. We know that, it belongs to the 

 fifth order, {ascomycetesj) because a good mi- 

 croscope shows us that its spores are in ascif 

 or little vesicles. Mr. Berkeley believes that 

 the various species of this fungus attack per- 

 fectly healthy plants. Still no botanist can 

 positively state how it grows on any one of 

 them. The best authorities think that it 

 grows in the form of a mould, which is called 

 by them oidium ; and conceive that very possi- 

 bly it makes its first appearance at the stomata. 

 But nobody has found that its mycelium, or 

 spawn, actually gets up into the leaves ; for in 

 its early stage it is a jointed mould, seemingly 

 superficial. Now, when we find the hop, the 

 bean, the pea, and the whole series of legu- 

 minous plants withering under the triumph of 

 this disease year after year — when it is the pest 

 of our beautiful peach-house, and even rages on 

 some of our finest trees, as the sycamore — what 

 a lamentable state of ignorance prevails, that 

 we can say no more of it than has just been 

 announced. Well might sir Isaac Newton say 

 to Halley, when speaking of science, " There is 

 game ip every bush, if you choose to beat for it." 



