EXPLANATION OF THE FIGURES OF THE PLATE. Fig. 1. Reproductive spore or germ of the Oidium Tuckeri, largely magnified. Fig. 2. Oidium Tuckeri, largely magnified. m, m, m. Creeping filaments, or mycelium. c, c. "Crampons" (clamps, anchors) of the mycelium. t, t, t. "Tigelles," or erect filaments bearing the spores placed end to end. s, s, s. Spores on the " Tigelles.” Fig. 3. The Oidium Tuckeri in full vegetation on the skin of a grape, appearing to the naked eye as merely a white efflorescence. Fig. 4. Spore of the Oïdium Tuckeri beginning to germinate. Fig. 5. Fragment of the skin attacked by Oidium, on which flour of sulphur has been scattered. f,f,f. Grains of flour of sulphur. Fig. 6m, m, m. Fragments of mycelium broken and deformed. s, s, s, Spores shrunk and distorted. The greater part have disappeared; only a small number are seen. Fig. 7. Flour of sulphur, magnified. Fig. 8. Fine sleet of sulphur, largely magnified. Fig. 10. Triturated sulphur reduced to an impalpable powder, magnified to the same degree as the flour of sulphur in Fig. 7. Common triturated sulphur has nearly the same forms, but the fragments are much more voluminous. Fig. 11. The Vergnes Bellows. t. Nozzle by which the air enters and is blown out again, charged with the sulphur-dust. gauze with large meshes to sift the sulphur. lows, serving as reservoir for the sulphur. m. Wire c. Cavity of the belb. Stopper to the orifice in the upper wood, by which the sulphur is introduced. Fig. 12. Box with a tuft. |