The thicker ends of the spore-sacs (asci) open while still within the perithecium; the spores issue united in a bundle, and are emitted from the aperture of the perithecium. In consequence of their somewhat glutinous consistence, they remain united even after their extrusion, and form white silky flocks; their number in the 20 or 30 heads sometimes produced from a single ergot, often exceeds a million. The heads themselves die in two or three weeks after they have begun to make their appearance. They represent the true fructification of the fungus. This state of the plant appears to have been first noticed in 1801 by Schumacher, who called it Sphæria; it was subsequently known as Cordiceps, Cordyliceps, Kentrosporium, etc., until Tulasne proved it to be the final stage of development of ergot.
The three different forms of this structure, namely, the mycelium, the ergot, and the fruit-bearing heads, are therefore merely successive states of one and the same biennial fungus, which have been appropriately united by Tulasne under the name of Claviceps purpurea. The middle stage forms the sclerotium, which occurs in a large number of the most various fungi, and is a special state of rest of these plants. The direct proof that the mycelium is produced from spores of the fruit-head sown on ears of rye, was supplied by Kühn in 1863. It has already been mentioned that the same organism is produced from conidia; whence it appears that a twofold formation of ergot is possible, as is frequently the case in other fungi.
Description—Spurred rye, as found in commerce, consists of fusiform grains, which it is convenient to term ergots. They are from ⅓ to 1½ inch in length, and ½ to 4 lines in diameter; their form is subcylindrical or obtusely prismatic, tapering towards the ends, generally arched, with a longitudinal furrow on each side. At the apex of each ergot, there is often a small whitish easily detached appendage, while the opposite extremity is somewhat rounded. The ergots are firm, horny, somewhat elastic, have a close fracture, are brittle when dry, yet difficult to pulverize. The whitish interior is frequently laid bare by deep transverse cracks. The tissue is but imperfectly penetrated by water, even the thinnest sections swelling but slightly in that fluid.
Ergot of rye has a peculiar offensive odour, and a mawkish, rancid taste. It is apt to become deteriorated by keeping, especially when pulverized, partly from oxidation of the oil, and partly from the attacks of a mite of the genus Trombidium. To assist its preservation, it should be thoroughly dried, and kept in closed bottles.
Microscopic Structure—In fully developed ergot, no organs can be distinguished. It consists of uniform, densely felted tissue of short, thread-like, somewhat thick-walled cells, which are irregularly packed, and so intimately matted together that it is only by prolonged boiling of thin slices with potash, and alternate treatment with acids and ether, that the individual cells can be made evident. Without such treatment, the cells even in the thinnest sections, show a somewhat rounded, nearly isodiametric outline. This pseudo-parenchyme of ergot exhibits therefore an aspect somewhat different from that of the loosely felted cells (hyphæ) of other fungi. Ergot nevertheless is not made up of cells differing from those of fungi generally. If thin longitudinal slices of the innermost tissue are allowed to remain in a solution of chromic acid containing about 1 per cent., they will distinctly show the hyphæ, which are however considerably shorter than those of other fungi. They contain numerous drops of fat oil, but neither starch nor crystals. It is remarkable that this nearly empty and not much thickened parenchyme should form so compact and solid a tissue.
The cell-walls of the tissue of ergot are not coloured blue, even after prolonged treatment with iodine in solution of potassium iodide; or when the tissue has been previously treated with sulphuric acid, or kept for days in contact with potash and absolute alcohol at 100° C. In this respect the cellulose of fungi differs from that of phanerogamic plants.
Of the outermost rows of cells in ergot, a few only are of a violet colour, but they are not otherwise distinguishable from the colourless tissue,—or at most by the somewhat greater thickness of their walls.
Chemical Composition—The composition of ergot has been elaborately investigated by Wiggers as early as 1830. The drug contains about 30 per cent. of a non-drying, yellowish oil, chiefly consisting of olein, palmitin, and small proportions of volatile fatty acids, especially acetic and butyric, combined with glycerin. The large amount of oil is remarkable; the fungi, dried at 100°, usually contain not more than 5 per cent. of fat, mostly much less; they are on the other hand much richer in albumin than ergot of rye. The oil of the latter, as extracted by bisulphide of carbon, is accompanied by small quantities of resin and cholesterin ([see p. 420]). It is erroneous to attribute to this oil the poisonous properties of ergot, although it has been shown by Ganser[2764] to display irritating properties when taken in doses of about 6 grammes. But the effects observed appear dependent on the presence in it of resin.
According to Wenzell (1864), ergot of rye contains two peculiar alkaloids, which he designated Ecboline and Ergotine,[2765] and claimed to be the active principles of the drug. They were, however, got merely as brownish amorphous substances.
The two bases of ergot are, according to Wenzell, combined with Ergotic Acid, the existence of which has been further admitted by Ganser. It is said to be a volatile body yielding crystallizable salts.