Children have been poisoned by the berries, but may on occasion eat them with no other ill effect than a stomach ache, or, if eaten in excess, sickness and purging. The berries “have even been used instead of raisins for plum puddings with no effects out of the ordinary” (Ewart). The plant has also been used in Queensland and elsewhere as a substitute for spinach. In several cases the plant has proved fatal. Gohier gave 3 kilogrammes (6½ lb.) of the green plant to a horse and observed no serious symptoms. Cases of poisoning are recorded for calves, sheep, goats and pigs (Chesnut and Wilcox). According to Lehmann, Schraber and Haller, the berries are poisonous to ducks and chickens. Over thirty years ago the death of a number of cattle in Victoria was recorded as being due to poisoning by this weed.
Though cases of poisoning of stock are rare, partly perhaps because the plant is a weed of arable land and partly because animals are likely to avoid it unless starved, Solanum nigrum must be regarded as a poisonous plant, any examples of which may prove toxic. The downy and more prostrate form has been considered the most poisonous.
The “Wonderberry,” said to be a hybrid between Solanum guineense and S. villosum, which are probably varieties of S. nigrum, cannot in England be distinguished from the last named, the fruits of which appear to be edible in some countries and poisonous in others. Greshoff found that fruits of the “Wonderberry” contained more Solanine than the wild English S. nigrum or the Canadian form known as the “Huckleberry,” and hence they should not be eaten.
Toxic Principle. The Garden Nightshade, in particular the berries, contains the alkaloidal glucoside Solanine, of which the formula is considered doubtful. Solanine is readily converted into sugar and the poisonous Solanidine. It was isolated from the berries in 1821, and though decidedly active in sufficient quantity is not a violent poison. A small quantity of Solanine is present in the stem and berries, but these are probably less poisonous than green potatoes (p. [54]).
Symptoms. The symptoms of poisoning are apparently much the same in man and animals: “Stupefaction; staggering; loss of speech, feeling, and consciousness; cramps and sometimes convulsions. The pupil is generally dilated.”
REFERENCES.
[4], [10], [11], [16], [17], [52], [53], [57], [73], [81], [82], [128], [141], [161], [203], [235], [240].
Bittersweet (Solanum Dulcamara L.). Some doubt exists in regard to the toxic character of this common denizen of the hedge-row, some persons regarding the berries as harmless and others as poisonous. Possibly the plant varies in toxicity. Floyer states that 30 berries killed a dog. Though stock rarely touch the plant there seems to be no doubt that it is poisonous, stem, leaves, and berries containing the toxic alkaloid found in S. nigrum and the potato (q.v.), and it is especially possible that poisoning may follow the ingestion of the berries. Johnson and Sowerby (1861) say that the leaves are narcotic, causing nausea and giddiness, and that the fruit is equally harmful, though no fatal cases then seemed to be recorded. Gillam records (Vet. Record, 1906) a case of poisoning of sheep. An anonymous writer in the Mark Lane Express (July 24, 1911) states emphatically that this plant is very poisonous, and that he has known 14 per cent. of the sheep on a farm to be killed by it in a year, while his veterinary surgeon had had 40 cases that season, some proving fatal.
Toxic Principle. Like S. nigrum, the stems, leaves, and berries of Bittersweet contain Solanine. The berries are stated by Esser to contain 0·3 to 0·7 per cent. of Solanine. The stems also contain the glucoside Dulcamarin (C22H34O10), which imparts a bitter taste to the plant, but which has not been fully studied.
Symptoms. In the case recorded by Gillam (see above) the symptoms observed in sheep were small intermittent pulse, temperature 104° F., quickened respiration, staggering gait, dilated pupil, and greenish diarrhœa. The symptoms appear to be the same in the case of cattle (Farmer and Stockbreeder, July 10, 1911).