292 OBSEUVATIONS ON THE VINE MILDEW, 



quence to root up the plant. In doing so the proprietor will not 

 make a great sacrifice, since the grapes wliich he cultivates are 

 not saleable when diseased, and he will not have to regret being 

 the involuntary cause of greater mischief." 



The importance of the foregoing memoir cannot be denied, 

 though written under very strong views with regard to the effects 

 of fungi on living vegetables, and as it seems to me chargeable 

 in parts with what the Germans call inconsequence. The fungal 

 theory of the potato disease, as it is termed, was nowhere more 

 strongly opposed or even ridiculed than in France, insomuch 

 that more than one botanist who commenced with it, was forced 

 to yielfl to the pressure from without. It is extraordinary, how- 

 ever, that of all the theories that were broached, none has been 

 retained by their several advocates except the fungal theory, 

 which not only is as ardently retained as ever by its first adhe- 

 rents, but is daily gaining ground, and has been eventually 

 adopted by some who were at first the strongest in their opposi- 

 tion. I am not, liowever, going to discuss again a subject which 

 has been so much canvassed, or which has lost its interest with 

 most readers. My opinions were fully stated in the first nvmiber 

 of this Journal, and I have never yet seen reason to alter them. 



It is curious that with respect to the vine disease, the majority 

 are in favour of the fungal theory, and my friend Dr. Leveille is 

 almost alone on tlie other side. It is not to be denied that his 

 arguments are extremely plausible, and that there is mucli in his 

 observations that is worth attentive consideration, but I cannot 

 always admit his data. It may be very true that neither he nor 

 M. Decaisne, of whom no botanist will speak without the greatest 

 respect and self distrust, have been able to detect mycelium 

 within any part of the plant ; but it is no less true that myself 

 and Mr. G. Hoffman have seen it most distinctly, and tliat the 

 figure given in the Gardeners' Chronicle in November, 1847, 

 was drawn from specimens lying on the field of the microscope 

 in which the growth through tlie stomata was as evident as that 

 of JBotrytis infestans, through the stomata of the potato. The 

 disease, far from disappearing early, as related in Dr. Leveille's 

 notes, continued, at least in some instances, in this country as 

 long as the leaves were on the trees, specimens having been for- 

 warded to me from Margate quite late in the year from vines 

 which I had studied in July ; and in November Mr. Hoffman, 

 than whom there are few more careful observers, and who has 

 an excellent microscope, with very great powers of manipula- 

 tion, assured me that he then distinctly traced the mycelium in 

 the buds when the leaves had fallen. 



The same excellent observer witnessed its propagation from 



