It would not be at all surprising if our American grapes, so utterly despised heretofore in Europe, should soon be planted extensively there in vineyards, as it seems they are not attacked by the mildew, which is threatening the European varieties with complete destruction. This would create a singular and unexpected revolution in vine growing. We copy the following article from the Gardeners' Chironiele:

It it difficult even for those who witnessed the desolation caused by the prevalence of the potato-murrain, in 1845, to conceive the utter despair which has seized almost all the vine districts, from the Rhine to Madeira, in consequence of the increasing present failure of the vintage, and the prospect of entire destruction which threatens many of the most valuable vineyards. Not only do the grapes decay long before maturity, but plant after plant is dying, in spite of every effort to ward off the mortality. At the present moment^ more especially the rich districts of Portugal, on the banks of the Douro and the Upper and Lower Corgo, which supply to so great an extent the London markets, are following the fate of Madeira, and both merchants and laborers are too sensibly alive to the ruin which awaits them, unless some remedy or providential alleviation be found. Happily, however, the principals are not inactive, but are seeking for every information which may give the slightest hope of relief We have before us a very sensible pamphlet by Mr. Quarlks Harris, addressed to gentlemen in the wine trade,* and we have just received a collection of diseased grapes and leaves, forwarded (with laudable zeal, for when sent there was a temporary alleviation of the malady,) from the Upper and Lower Corgo by Mr. Gas8IOt, of the firm of MartiniEZ, Gassiot & Co., of Mark Lane. These present the appearances which have been so often described The leaves and fruit are covered with Oidium, and as in the Madeira specimens, there is an abundant admixture, not only of Tricoihecium rouum, which is common everywhere, but of a charming species of Conisporivm, which has occurred before only on the diseased 'produce from Madeira. The disease was indeed quite as virulent as in the worst English specimen?, and the shoots, instead of presenting a clear healthy brown, were partially or entirely black, an unfailing indication, unhappily, of unhealthy shoots the ensuing year.

The grapes are in every stage of disease from simple depauperation to downright corruption.

Though the method employed by M. Orison is so efficacious when practised on a small scale, it requires too much capital for the poorer cultivators of Portugal; and the total amputation recommended by some authors is hope so long delayed'as to make the heart of the needy vinedresser sick indeed. Mr. Robert Thompson, however, to whom we are indebted for much of the accompanying information, writes as follows: "Bleeding the vine, by cutting its roots, has been recommended, and instances have been adduced to prove the efficacy of this mode of treatment; but the vine has such power of developing shoots and leaves that I can not imagine how plethora could take place. Beside, we find weakly plants are as liable to the disease as those of full habit It may, therefore, be concluded that the beneficial result of root-pruning depends on something else. It does away with tap-roots that perhaps were worse than useless from being in a dry subsoil, and which, from being the principal feeders, have not afforded an adequate supply to the vessels connected with them. I had some Apricot trees so attacked year after year with mildew that not one fresh healthy green leaf could found. They were taken up carefully in autumn, and the border was well trenched.

The trees were then replanted, and afterward bore a healthy foliage. The flame may hold good as regards the vine".

* Remarks and Observations on the Vine Disease now Savaging the Wine Countries of Europe, with Recipes for its Cure, and Microscopic Examinations, executed by TUFFEN Wax, Esq., 51 nation Garden. Smith & Wildeb, 1868, p. 10, table 1.

It appears, moreover, that the American varieties or species, when introduced into Europe, are very slightly if at all subject to be attacked; and on the contrary, the European varieties, when cultivated in the Northern States, at least of America, are so subject to mildew that no one will persist in their cultivation on a large scale, though in conservatories the sulphur system has been adopted, it is said, for years before the disease became generally known in Europe. The Americans have had cultivators from the wine countries on the Rhine and elsewhere, who have carried with them their own varieties, concluding from the soil and climate that they should make a fortune. But in three years all their plants were swept off by the mildew.

The attention, therefore, of the more opulent vine growers should be especially directed to the superior varieties of American grapes, especially such as are not of a foxy flavor, and the sooner such varieties are procured the better. Orders should be immediately transmitted through safe and judicious hands, for cuttings, or what would be better still, some intelligent practical men should themselves at once proceed to America to obtain them from the source most free from suspicion, or at least procure the best which at present exist in Europe. It is true that some years must elapse before any general benefit could be derived, but if this plan holds forth no hope, there is at present little reliance on any other. It is true that the American kinds are by no means equal to the European, and less calculated for wine, as it should seem from the small product of the American vintage; but a judicious selection might be expected in good hands not to be valueless.

We have in vain inquired after the vine mildew in the Southern States, though we have seen an imperfect specimen which had a very suspicious appearance. Unfortunately, among some fifteen hundred authentic specimens of the fungi of the United States described by Schweinitz, which we have lately received, there is not any specimen of Erysiphe necator, which is sometimes so destructive to the fruit.

It is curious that the grape mildew should have found its way to America from England, whereas there is some reason to believe Morren's notion that the Botrytis infestans of the potato-murrain traveled into Europe from America. M. J. B.