Botanical Origin—Claviceps purpurea Tulasne, a fungus of the order Pyrenomycetes, of which ergot is an immature form, it being the sclerotium (termed in the British Pharmacopœia compact mycelium or spawn) developed within the paleæ of numerous plants of the order Gramineæ.

Ergot is obtained almost exclusively from rye, Secale cereale L.; but the same fungus is produced on grasses belonging to many other genera, as Agropyrum, Alopecurus, Ammophila, Anthoxanthum, Arrhenatherum, Avena, Brachypodium, Calamagrostis, Dactylis, Glyceria, Hordeum, Lolium, Poa, and Triticum. Other organisms of diverse form, but of doubtful specific distinctness, are developed in Molinia, Oryza, Phragmites, and other grasses. In the order Cyperaceæ (e.g., Scirpus), peculiar ergots are known.

History—Although it is hardly possible that so singular a production as ergot should be unnoticed in the writings of the classical authors, we believe no undoubted reference to it has been discovered.[2750] The earliest date under which we find ergot mentioned on account of its obstetric virtues is towards the middle of the 16th century, by Adam Lonicer of Frankfort, who describes its appearance in the ears of rye, and adds that it is regarded by women to be of remarkable and certain efficacy.[2751] It is also very clearly described in the writings of Johannes Thalius, who speaks of it as used “ad sistendum sanguinem.”[2752] In the next century it was noticed by Caspar Bauhin, who termed it Secale luxurians,[2753] and by the English botanist Ray,[2754] with allusion to its medicinal properties.

Rathlaw, a Dutch accoucheur, employed ergot in 1747. Thirty years later Desgranges of Lyons prescribed it with success; but its peculiar and important properties were hardly allowed until the commencement of the present century, when Dr. Stearns of New York succeeded in gaining for them fuller recognition.[2755] Ergot of rye was not, however, admitted into the London Pharmacopœia until 1836.[2756]

The use of flour containing a considerable proportion of ergot, gives rise to a very formidable disease, distinguished in modern medicine as Ergotism, but known in early times by a variety of names, as Morbus spasmodicus, convulsivus, malignus, epidemicus vel cerealis, Raphania, Convulsio raphania[2757] or Ignis sancti Antonii.

Some of the malignant epidemics which visited Europe after seasons of rain and scarcity during the middle ages have been referred with more or less of probability to ergot-disease.[2758] The chronicles of the 6th and 8th centuries note the occurrence of maladies which may be suspected as due to ergotized grain. There is less of doubt regarding the epidemics that prevailed from the 10th century and were frequent in France, and in the 12th in Spain. In the year 1596 Hessen (Hessia) and the adjoining regions were ravaged by a frightful pestilence, which the Medical Faculty of Marburg attributed to the presence of ergot in the cereals consumed by the population. The same disease appeared in France in 1630, in Voigtland (Saxony) in the years 1648, 1649, and 1675; again in various parts of France, as Aquitaine and Sologne, in 1650, 1670, and 1674. Freiburg and the neighbouring region were visited by the same malady in 1702; other parts of Switzerland in 1715-16; Saxony and Lusatia in 1716; many other districts of Germany in 1717, 1722, 1736, and 1741-2.[2759] The last epidemic in Europe occasioned by ergot appears to be that which, after the rainy season of 1816, visited Lorraine and Burgundy, and proved fatal to many people of the poorer class. Ergot disease is sometimes observed in Abyssinia at the present day,[2760] and a few cases of it have even been lately recorded in Bavaria.[2761]

Formation—The true nature of ergot has long been the source of a great diversity of opinion, not set at rest by the admirable researches of L. R. Tulasne, from whose Mémoire sur l’Ergot des Glumacées,[2762] the following account is for the most part extracted.

The formation of ergot often affects only a few caryopsides in a single ear; sometimes, however, more than twenty. In the former case, the healthy development of the other caryopsides is not prevented, but if too many are attacked, the entire ear decays. The more isolated ergots generally grow larger, and attain their greatest size on rye which springs up here and there among other cereals.

The first symptoms of ergot-formation is the so-called honey-dew of rye, a yellowish mucus, having an intensely sweet taste, and the peculiar disagreeable odour frequently belonging to fungi. Drops of this mucus show themselves here and there on the ears in the neighbourhood of diseased grains, and attract ants and beetles of various kinds, especially the yellowish-red Rhagonycha melanura Fabr., but not bees. On this account the beetle in question has been supposed to be instrumental in the development of ergot, and it may possibly be so, but only by transporting the saccharine mucus from one plant to another.

The honey-dew of rye contains neither oil-drops nor starch. After dilution with water, it produces a rapid and abundant separation of cuprous oxide from an alkaline solution of cupric tartrate. Dried over sulphuric acid, it solidifies into a crystalline mass. After a few days the drops of honey-dew dry up and disappear from the ear. The grain at this period becomes completely disintegrated, and devoid of starch.

The ergotized soft ovaries are covered with, and penetrated by a white, spongy, felted tissue, the mycelium of the young fungus. It is made up of slender, thread-like cells, the hyphæ, the outer layer of which consists of radially-diverging cells, the basidia. The whole mycelium forms by its crevices and folds a number of cavities opening externally; from its outer layer, which is also called the hymenium or spermatophorum, an immense number of agglutinated, elongated granules, the conidia, are separated. These cells, the products of the basidia, are not more than four mkm. in length, and give the floral organs the appearance of being covered with a whitish dust. The honey-dew likewise contains an abundance of conidia, but it is only on dilution that they are precipitated and become easily perceptible; the formation of the honey-dew is intimately connected with that of the conidia themselves. Ergot in this primary or mycelium stage was regarded as an independent fungus by Léveillé (1827), who named it Sphacelia segetum. According to Kühn (1863), it may even be directly by germination of the conidia within the ears of rye.

The mycelium penetrates and envelops the caryopsis, with the exception of the apex, and thereby prevents its further growth, destroying especially the epicarp and the embryo. At the base of the caryopsis, there is formed by tumefaction and gradual transverse separation of the thread-cells of the mycelium, a more compact kernel-like body (the future ergot) violet-black without, white within, which gradually but largely increases in size, and ultimately separates from the mycelium as the loose tissue of the latter dries and shrinks up after the completion of its functions. By this growth, the remains of the caryopsis, still recognizable by their hairs and by the rudiments of the style, as well as by the surviving portions of the mycelium-tissue, become visible above the paleæ on the apex of the mature ergot, now projecting prominently from the ear. Very rarely the ergot is crowned by a fully developed seed; in the commercial drug, the apex is usually broken off.

It is evident that in the process of development just described, the very tissue of the caryopsis of the rye does not undergo a transformation, but that it is simply destroyed. Neither in external form, nor in anatomical structure does ergot exhibit any resemblance to a caryopsis or a seed, although its development takes place between the flowering time and that at which the rye begins to ripen. It has been regarded as a complete fungus, and as such was named by De Candolle (1816) Sclerotium Clavus and by Fries Spermædia Clavus.

No further change in the ergot occurs while it remains in the ear; but laid on damp earth, interesting phenomena take place. At certain points, small orbicular patches of the rind fold themselves back, and gradually throw out little white heads. These increase in size, whilst the outer layers of the neighbouring tissue gradually lose their firmness and become soft and rather granular, at the same time that the cells, of which they are made up, become empty and extended. In the interior of the ergot, the cells retain their oil drops unaltered. The heads assume a greyish-yellow colour, changing to purple, and finally after some weeks stretch themselves towards the light on slender shining stalks of a pale violet colour. The stalks often attain an inch in length, with a thickness of about ½ a line. They consist of thin, parallel, closely-felted cell-threads, devoid of fat oil. Ergot is susceptible of this further development only so long as it is fresh, that is to say, at most until the next flowering time of rye. Within this period however, even fragments are capable of development. There are sometimes also produced colourless threads of mould which belong to other fungi, as Verticillium cylindrosporum Corda, and which frequently overgrow the Claviceps.[2763]

At the point where the stalk joins the spherical or somewhat flattened head, the latter is depressed and surrounds the stalk with an annular border. After a short time there appear on the surface of the head, which is ⅒ of an inch in diameter, a number of brownish warts, in which are the openings of minute cavities, the conceptacula or perithecia. On transverse section, they appear arranged radially round the circumference of the head. In each cavity are a large number of delicate sacs, only 3-5 mkm. thick, and about 100 mkm. long, the thecæ or asci, each containing, as is usual in fungi, 8 spores. These are simple thread-shaped cells, filled with a homogeneous solid mass.

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.

A crystallized colourless alkaloid, Ergotinine, C₃₅H₄₀N₄O₆, has been isolated (1877-1878) by Tanret, a pharmacien of Troyes. He obtained it to the amount of about 0·04 per cent., some amorphous ergotinine moreover being present. Tanret exhausts the powdered drug with boiling alcohol, which by evaporation affords a fluid resin and an aqueous solution, besides a fatty layer. Some ergotinine is removed from the resin by shaking it with ether, and mixed with the main liquid. This is acidulated and purified by means of ether. Lastly, the ergotinine is extracted by adding a slight excess of carbonate of potassium and shaking with ether, and recrystallizing from alcohol. The solutions of ergotinine turn very soon greenish and red; they are fluorescent. Sulphuric acid imparts to it a red, violet, and finally blue hue.

Dragendorff and several of his pupils, since 1875, have isolated the following amorphous principles of the drug under notice:—(1) Sclerotic acid (doubtful formula C₁₂H₁₉}NO₉), said to be a very active substance, chiefly in subcutaneous injections. About 4 per cent. of colourless acid may be obtained from good ergot of rye. (2) Scleromucin, a mucilaginous matter, which may be precipitated by alcohol from aqueous extracts of the drug. Scleromucin when dried is no longer soluble in water. (3) Sclererythrin, the red colouring matter, probably allied to anthrachinon and the colouring substances of madder, chiefly to purpurin. (4) Sclerojodin, a bluish-black powder, soluble in alkalis. (5) Fuscosclerotinic acid. (6) Picrosclerotine, apparently a highly poisonous alkaloid. Lastly (7) Scleroxanthin, C₇H₇O₃ + OH₂; and (8) Sclerocrystallin, C₇H₇O₃, have been obtained in crystals; their alcoholic solution is but little coloured, yet assumes a violet hue on addition of ferric chloride.

Tanret also observed in ergot of rye a volatile camphoraceous substance.

Ergot, in common with other fungi,[2766] contains a sugar termed Mycose, closely allied to cane-sugar, and probably identical with Trehalose (see p. 417). Mycose crystallizes in rhombic octohedra, having the composition C₁₂H₂₂O₁₁ + 2H₂O. Mitscherlich obtained of it about one-tenth per cent. It appears that the sugar exuded in the first stage of growth of the fungus,—the so-called rye honey-dew,—is in its principal characters different from mycose. Instead of the latter, Mitscherlich, as well as Fiedler and Ludwig, sometimes obtained from ergot Mannite.

Schoonbroodt also found in ergot Lactic Acid. Several other chemists have further proved the presence of acetic and formic acids.

Starch is entirely wanting in ergot at all times. The drug yields about 3 per cent. of nitrogen, corresponding probably to a large amount of albuminoid matter. Ganser, however, obtained only 3·2 per cent. of albumin soluble in water.

When ergot or its alcoholic extract is treated with an alkali it yields, as products of the decomposition of the albuminoid matters, ammonia or ammonia-bases, according to Ludwig and Stahl, Methylamine,—according to others, Trimethylamine. Manassewitz, as well as Wenzell, state that phosphate of trimethylamine is present in an aqueous extract of ergot, but Ganser ascertained that no such base pre-exists in ergot. We have found that the crystals which abound in the extract, after it has been kept for some time, are an acid phosphate of sodium and ammonium with a small proportion of sulphate.[2767]

Production and Commerce—Ergot of rye is to be met with in all the countries producing cereals; we have seen it in the high valleys of the Alps, and Schübeler states that it grows in Norway, as far north as 60° N. lat.

The drug is chiefly imported into London from Vigo in Spain and from Tenerife; it is also shipped from Hamburg and France. Dr. de Lanessan, writing to one of us from Vigo in 1872, remarks that vast quantities of rye are grown in Galicia, and that owing to the humidity of the climate the grain is extensively ergotized,—in fact the parasite is present in one ear out of every three. At the time of harvest the ergots are picked out, and the rye is thus rendered fit for food.

Southern and Central Russia furnish considerable supplies of the drug. In the central parts of Europe, ergot does not everywhere occur in sufficient abundance to be collected, and it greatly diminishes as the state of agriculture improves. We have noticed that ergot from Odessa was of a slaty hue and in much smaller grains than that from Spain.

Uses—Ergot is principally used on account of its specific action on the uterus in parturition.

Other Varieties of Ergot—Ergot of Wheat (Triticum vulgare), which is in shorter and thicker ergots than that of rye, is picked out by hand in some parts of Italy and France, from grain intended to be used for the manufacture of vermicelli and other pastes; and such ergot is sold to druggists. Carbonneaux Le Perdriel[2768] has endeavoured to show that it is less prone to become deteriorated by age than that of rye, and that it never produces the deleterious effects sometimes occasioned by the latter.

The same writer asserts that Ergot of Oat is sometimes collected and sold either per se, or mixed with that of rye. It differs from the latter in the ergots being considerably more slender.

Ergot of the North African grass Arundo Ampelodesmos Cirillo, known as Diss, has been collected for use, and according to Lallemant[2769] is twice as active as that of rye. It is from 1 to 3 inches long by only about ⅒ of an inch broad, generally arched, or in the large ergots twisted spirally. We find it to share the structural character of the ergot of rye; it is in all probability the same formation, yet remarkably modified.