Bindweeds (Convolvulus sepium L. and C. arvensis L.). The creeping rootstocks and foliage, as well as the seeds, are held to be more or less poisonous if eaten in quantity, and as long ago as 1872 Olver recorded (Veterinarian, 1872) that pigs which ate freely of Convolvulus died. These species, when eaten in considerable quantity, appear to be cathartic and purgative, causing symptoms resembling those due to jalap.
REFERENCES.
[82], [141], [190], [203], [254].
SOLANACEÆ.
Thorn Apple (Datura Stramonium L.). This species is an escape from cultivation, but on occasion occurs plentifully in gardens, and if allowed to seed may escape to arable fields and find its way to stock, though it does not appear to have done so in Britain. Several species of Datura are recognized as virulent poisons in North America, where they are known as Jimson Weeds. All parts are poisonous, especially the seeds, which have a somewhat sweetish taste, and have frequently caused accidents to children who have eaten them. Cases are recorded in the United States in which cattle have been poisoned by eating the leaves of young plants in hay. Live stock, however, usually avoid the plant, which has an unpleasant odour and taste, while the seeds are enclosed in thorny capsules. Walsh states that the seeds are very fatal to young ostriches. Drying does not destroy the toxicity.
Toxic Principle. The Thorn Apple is usually stated to contain the highly poisonous narcotic alkaloid Daturine, but this appears to be a mixture of the two alkaloids Hyoscyamine (C17H23O3N) and Atropine (C17H23O3N), which, together with the alkaloid Scopolamine, or Hyoscine (C17H21O4N), have been found in the plant, the principal constituent being Hyoscyamine. In some analyses as much as 0·33 per cent. of Atropine has been found in the seeds, and 0·2 per cent. in the leaves (Pammel). The three alkaloids occur together to the extent of 0·48 to 3·33 per cent. in the leaves, 0·43 per cent. in the flowers, and 0·1 per cent. in the root, Hyoscyamine predominating (Esser). An investigation conducted at the Imperial Institute (Bul. Imp. Inst., 1911) showed the amount of alkaloids in European specimens to be:—
| Seeds | 0·21 to 0·48 | per cent. |
| Leaves | up to 0·4 | „ |
| Stems | average 0·22 | „ |
| Roots | average 0·17 | „ |
Symptoms. The general effect of Datura poisoning appears to resemble that of Atropa Belladonna, but is by some considered more rapidly effective. There is paralysis, dilatation of the pupils, suspension of secretion and of the inhibitory fibres of the vagus, leading to rapid action of the heart (Lander). Poisoning may terminate fatally. Pammel quotes Winslow as stating that two grains of Atropine produce mild toxic symptoms in the horse; cattle are as susceptible as horses, though herbivora are not so easily influenced as carnivora. Chesnut gives the following symptoms: “Headache, vertigo, nausea, extreme thirst, dry, burning skin, and general nervous confusion, with dilated pupils, loss of sight and of voluntary motion, and sometimes mania, convulsions, and death.” Walsh gives the toxic symptoms in ostriches as staggering gait, spasmodic jerking of the neck, stupor, and death in a comatose state.
REFERENCES.
[4], [10], [16], [39], [52], [53], [73], [81], [92], [128], [141], [170], [203], [213], [260].