xxv.J CORN" MILDEW AND BARBERRY BLIGHT. 177 



spores of the mildew fungus : the threads do not enter 

 the open stomate, but are seen boring through the cells 

 of the barberry leaf. This special drawing, the only 

 one of real interest in the paper, is not original, but a 

 copy from a published book. We consider it a weak 

 point, therefore, in Mr. Plowright's case that in his 

 elucidation of the only critical part of his subject he has 

 fallen back upon a many times copied and recopied book 

 illustration. How valuable a new illustration of this won- 

 derful phenomenon would have been ; but at present, as 

 far as we know, no one has ever ventured on a second 

 original representation. We do write in this way with a 

 view to throw doubt on the accuracy of the drawing. 

 Every one who has a microscope can easily see Uredo 

 spores, Puccinia spores, and JEcidium spores germinate, 

 and many are the original published illustrations. How 

 is it, we may ask, then, that so few can see pro-mycelium 

 spores piercing the epidermal cells of a barberry leaf, or, 

 if they can so see them, do not venture on new illustrations ? 

 It was specially necessary that Mr. Plowright should, if 

 possible, have published an original of this phenomenon. 

 As Mr. Plowright is now the chief teacher of the con- 

 nection of corn mildew and barberry blight in this country, 

 it will be interesting to record his words in reference to 

 infecting barberries with spores from the fungus of corn 

 mildew. He writes : " On 14th April, 17th April, and 9th 

 May, respectively, I infected one of these (barberry bushes) 

 with spores from the pro-mycelium of Puccinia graminis 

 from wheat and twitch, and kept the three remaining 

 barberries as control plants. In due course the jEcidium 

 appeared upon the infected plants, the control plants 

 remaining free from ufflcidium, and they continued so for two 

 months, when they were cut down, the experiment being 

 then ended." Further on Mr. Plowright writes : " On 1 5th 

 and 17th April T placed upon nine wheat seedlings some of 

 the same pro-mycelium spores which were used for infecting 

 the barberries, and upon 7th May one of the wheat plants 



