Royal Society. 7\ 



In 1853, the disease attacked the vines bodily, and almost simul- 

 taneously : whereas, in 1854, the Oidium appears to be creeping 

 out of the skin of the last year's wood, and insidiously to extend 

 itself over the branches. 



The globules (to which allusion has been made above) cover the 

 young shoots. I have been familiar with these for twenty-three 

 years past, and the Douro farmers call them the " perspiration " of 

 the vine. They do not indicate disease, whereas the smallest 

 possible quantity of the po' branco, or white powder, being transferred 

 to a perfectly healthy vine, immediately infected it. 



In the Alto-Douro the oranges, lemons, citrons and limes have 

 all been blighted, and every kind of vegetable appears to be suffer- 

 ing from sickness. 



The vines which suffered most in the Alto-Douro, in 1S53, were 

 the Muscatel, Malvazia, Alvarilhao, Ferial, Agadanho and Senzao. 

 Since my arrival in this country I have noticed that the vines 

 grown on walls in the open air, vines grown in greenhouses, vines 

 grown in hot-houses, vines forced, all show identically the same 

 effects of the Oidium of last year, as exist on the vines in the Alto- 

 Douro. 



Taking into consideration all the circumstances above narrated, 

 I have come to the conclusion, — 



That the Oidium is the cause, and not the effect of the disease ; that 

 the inclemency of the season in 1853, by checking the circulation 

 of the sap in the vines, produced a predisposition for disease ; that 

 if the Oidium continues to appear on the branches of the vines, it 

 is only too probable that it may in a very few years be destroyed; 

 that the globules are a sign of health and not of disease, and have no 

 connexion whatever with the fungus called Oidium ; and that if the 

 germ of the Oidium, probably still lurking on the old branches, can 

 be destroyed in the open air as effectually as it appears to have been 

 destroyed under glass, then I feel persuaded that all the vines in the 

 Port- wine districts of the Alto-Douro may be saved. 



■' Supplementary Note on the proposed Remedies for the Eradi- 

 cation of the Vine-Malady." 



1st. I will take the annual production of wines in the Port- wine 

 districts of the Alto-Douro at 80,000 pipes instead of °0,000, and 

 the number of vines to be treated as diseased at 80,000,000. 



2nd. The value of freehold land in that district, for the growth of 

 1000 vines, or one pipe of wine, may be estimated at 50/., yielding 

 an interest or rental of 3/. per annum. 



3rd. The total freehold value of the vineyards in those districts 

 may be estimated at 4,000,000/. sterling, giving an annual revenue 

 of 240,1)1)1)/. 



4th. In the event of the disease not being checked In its progress, 

 and the grapes being destroyed this year in the Alto-Douro, a mini- 

 mum lose of 240,000/, will be sustained, and should the vines perish, 

 tli- loss may be 4,000,000/. 



5th. Portugal is said to produce annually 1,000,000 pipes of 

 wine of all sorts and qualities, but I will estimate the total produe- 



