Various opinions have been formed as to the mode of propagation of the spur. Fontana has alleged that one variety of it may spread from plant to plant over a field; and that he has expressly transmitted it by contact from one ear to another.[1] His opinion and statement of facts are at variance with experiments lately made by Hertwig, a German physician, who found that even when the ear while in flower was surrounded for twelve days with powder of spurred rye, the healthiness of the future grain was not in the slightest degree affected.[2] The same results have also been obtained by Wiggers, and more recently by Dr. Samuel Wright.[3] Wiggers, however, although he could not produce spurs in the way indicated by Fontana, observed that the white dust on the surface of the spurs will produce the disease in any plant, if sprinkled in the soil at its roots, appearing therefore to be analogous to the sporules or spawn of the admitted fungi. Mr. Queckett has made the most precise experiments on the mode of reproduction of the disease. He succeeded in infecting rye repeatedly with ergot by means of the sporidia developed on the spurs; but it is remarkable that he could not in the same way infect wheat or barley.[4]
Description and analysis of Spurred Rye.—The spur varies in length from a few lines to two inches, and is from two to four lines in thickness. If it is long, there is seldom more than one or two on a single ear, and the remaining pickles of the ear are healthy. But the ears which have small spurs have generally several, sometimes even twenty; and when there are many, few of the remaining pickles are altogether without blackness at the tips.[5] The substance of the spur is of a pale grayish-red tint; and externally it is bluish-black or violet, with two, sometimes three, streaks of dotted gray. It is specifically lighter than water, while sound rye is specifically heavier, so that they are easily separated from one another.[6] It is tough and flexible when fresh, brittle and easily pulverized when dry. The powder is disposed to attract moisture. It has a disagreeable heavy smell, a nauseous, slightly acrid taste, and imparts its taste and smell both to water and alcohol. Bread which contains it is defective in firmness, liable to become moist, and cracks and crumbles soon after being taken from the oven.[7]—It is easily known, when entire, by its external characters. Its powder, which is of an obscure grayish-red hue, is best known by the action of solution of potash, which immediately disengages a powerful odour of ergot, and forms a lake-red pulp; and this pulp yields by filtration a splendid lake-red solution, which gives a beautiful lake-red flaky precipitate, when either neutralized by nitric acid, or treated with an excess of solution of alum.
Spurred rye has been repeatedly subjected to analysis. The earlier
- ↑ Lettre sur l'Ergot. Journal de Physique, vii. 42.
- ↑ Lorinser, Beob. und Vers. über die Wirkung des Mutterkorns, 1824, noticed in Robert's paper, p. 28.
- ↑ Edinburgh Medical and Surgical Journal, lii. 306. Harveian Prize Essay.
- ↑ Linnæan Transactions, xix. 140.
- ↑ Tessier, 421.
- ↑ Ibid. 428.
- ↑ Robert, 28
