GRAMINEÆ.
Darnel (Lolium temulentum L.). The grass known as Darnel, of the same genus as rye-grass, has been recognized for centuries as a harmful species, and it is considered by some authorities that it is really the tares of Scripture which the enemy sowed among the wheat. Its effect on eyesight was known to the ancients[[5]], and its objectionable character was noted by Shakespeare:—
[5]. E.g. Ovid says “Let the fields be clear of darnel that weakens the eyes.” In Plautus’ comedy, The Braggart Soldier, one servant says to another, “’Tis a wonder that you are in the habit of feeding on darnel with wheat at so low a price.” “Why so?” “Because you are so dim of sight.” [Agric. Jour. Union of S. Africa, Jan. 1914, p. 82.]
“Want ye corn for bread?
I think the Duke of Burgundy will fast
Before he’ll buy again at such a rate:
’Twas full of darnel: Do you like the taste?”
—I Henry VI, Act III, Sc. 2.
Its effect when mixed with flour was also referred to by Gerarde (1597): “The new bread wherein Darnell is, eaten hot, causeth drunkenness; in like manner doth beere or ale wherein the seede is fallen, or put into the mault.”
Before the seeding stage is reached Darnel seems to be quite suitable as a food for stock, only the seed or grain being poisonous, and this not invariably so. The chief danger perhaps is that the grain may not be thoroughly removed from cereal grains, and may thus find its way into bread or cereal stock foods. Though it has caused many cases of human poisoning, fatal results seem to be rare: Dr. Taylor could record no fatal case up to 1859. Darnel mixed with barley caused the poisoning of pigs (Veterinarian, 1842). Johnson and Sowerby (1861) state that Darnel has in several cases proved fatal to horses and sheep. The same authorities quote a case in which 80 inmates of Sheffield Workhouse were attacked by violent vomiting and purging from the use of oatmeal containing Darnel. At the Veterinary School at Lyons a horse was killed by giving it 2 kilogrammes (4·4 lb.) of Darnel. Cornevin concluded that the amounts of Darnel necessary to kill certain animals would be as follows:—
| Horse | 0·7 lb. per 100 | lb. live weight. |
| Ruminants | 1·5 to 1·8 lb. | per 100 lb. live weight. |
| Poultry | 1·5 to 1·8 lb. | „ „ |
| Dog | 1·8 lb. | „ „ |
He found pigs very little affected. As regards man 30 grammes (1 oz.) of the flour appear to be about the most that can be taken without showing dangerous symptoms.
The presence of Darnel flour in flour of the cereal grains may be determined by an examination of the starch granules, which are given by Cornevin as only 5 to 8µ; in diameter (compared with 25 to 4µ for rye), simple in general, but sometimes in groups of 2 to even 5, polyhedral or partly rounded, with a nucleus or fusiform nucleal cavity, and readily coloured blue with iodine; they resemble those of maize but are only about one-eighth the size.
Toxic Principle. The grains only are harmful, and contain the narcotic alkaloid Temuline (C7H12N2O), which Hofmeister showed to be a strong nerve poison, and which is said to occur to the extent of 0·08 per cent. in the seeds. Other authorities impute the toxic property to Loliine, while Smith states that the toxic principle is Picrotoxin. In relation to the grain fungal hyphæ have usually been found, though not invariably, 20 to 30 per cent. of the plants sometimes being free from it. The fungus (Endoconidium temulentum) is propagated vegetatively by means of mycelium. It appears to live symbiotically in the maturing grain, and perhaps to a slight extent renders possible the assimilation of nitrogen from the atmosphere; but Freeman observed that though generally stimulating to the Darnel, it is occasionally injurious to it. Esser sums it up by saying that according to most authorities who have investigated Darnel the fungus alone contains the toxic substance—the Temuline—and hence the grains in which the fungus does not occur should be harmless. The fungus is found in Darnel grain in all countries—Chile, Brazil, S. Africa, Persia, Spain, France, Sweden, Germany, etc. So far as can be ascertained there have been no feeding experiments to determine the difference in toxic character between fungus-infested and fungus-free grains. The dangerous properties are said to be most pronounced in wet seasons.
Symptoms. In France Darnel is called Ivraie, because, when brewed with barley, it acts as a narcotic intoxicant.
Darnel poisoning induces giddiness, drowsiness, uncertain gait, and stupefaction (Müller), and, in the older animals, vomiting, convulsions, loss of sensation and death (Pott).
The symptoms in the horse are dilatation of pupils, vertigo, uncertain gait, and trembling. The animal falls, the body is cold and the extremities are stiff, respiration is laboured, the pulse is slow and small, and there are convulsive movements of the head and limbs. There is rapid enfeeblement, and death may occur within thirty hours.
In pigs, foaming, convulsions and paralysis have been observed; the stomach and intestines were inflamed and the lungs congested.
REFERENCES.
[4], [16], [73], [81], [106], [128], [130], [141], [190], [203], [204],