EXTIEPATION OF VEGETABLES. 77 



local extirpation of noxious or useless vegetables in China, that, 

 with the exception of a few water plants in the rice grounds, it is 

 sometimes impossible to find a single weed in an extensive dis- \ 

 trict ; and the late eminent agriculturist, Mr. Coke, is reported to 

 have offered in vain a considerable reward for the detection of a 

 weed in a large wheat-field on his estate in England. In these 

 cases, however, there is no reason to suppose that dihgent hus- 

 bandry has done more than to eradicate the pests of agriculture 

 within a comparatively limited area, and the cockle and the dar- 

 nel will probably remain to plague the slovenly cultivator as long 

 as the cereal grains continue to bless him.* 



* Although it is not known that man has absolutely extirpated any vegetable, 

 the mysterious diseases which have, for the last twenty years, so injuriously 

 affected the potato, the vine, the orange, the olive, and silk husbandry, are 

 ascribed by some to a climatic deterioration produced by excessive destruction 

 of the woods. As will be seen in the next chapter, a retardation in the period 

 of spring has been observed in numerous localities in Southern Europe, as well 

 as in the United States, and this change has been thought to favor the multi- 

 plication df the obscure parasites which cause the injury to the vegetable just 

 mentioned. 



Babinet supposes the parasites which attack the grape and the potato to be 

 animal, not vegetable, and he ascribes their multiplication to excessive manur- 

 ing and stimulation of the growth of the plants on which they live. They are 

 now generally, if not universally, regarded as vegetable, and if they are so, 

 Babinet's theory would be even more plausible than on his own supposition. — 

 Etudes et Lectures, ii., p. 269. 



It is a fact of some interest in agricultural economy, that the oi'dium, which 

 is so destructive to the grape, has produced no pecuniary loss to the propri- 

 etors of the vineyards in France. " The price of wine," says Lavergne, " has 

 quintupled, and as the product of the vintage has not diminished in the same 

 proportion, the crisis has been, on the whole, rather advantageous than detri- 

 mental to the country." — Economie Burale de la France, pp. 263, 264. 



France produces a large surplus of wines for exportation, and the sales to 

 foreign consumers are the principal source of profit to French vine-growers. 

 In Northern Italy, on the contrary, which exports little wine, there has been 

 no such increase in the price of wine as to compensate the great diminution in 

 the yield of the vines, and the loss of this harvest is severely felt. In Sicily, 

 however, which exports much wine, prices have risen as rapidly as in France. 

 Waltershausen informs us that in the years 1838-'42, the red wine of Mount 

 Etna sold at the rate of one kreuzer and a half, or one cent the bottle, and 

 sometimes even at but two-thirds that price, but that at present it commands 

 five or six times as much. 



The grape disease has operated severely on small cultivators whose vineyards 

 only furnished a supply for domestic use, but Sicily has received a compensa- 

 tion in the inuuense increase which it has occasioned in both the product and 



