The related S. angustifolium has also been mentioned as objectionable. As regards the toxic principle these plants have not been closely studied, and it is not possible to give detailed symptoms.
REFERENCES.
Water Dropwort (Oenanthe crocata L.). This weed of marshes, ditches, and similar wet spots, has been a frequent cause of loss of stock. Cases of fatal human poisoning have also occurred, owing to the leaves having been mistaken for celery and the rootstock for parsnips. Several cases of the poisoning of cattle have been recorded in the veterinary journals, and sheep and cattle died on a farm near Bristol (Jour. Roy. Agric. Soc., 1898). Horses have also been poisoned. Johnson and Sowerby (1861) record the poisoning of 17 convicts near Woolwich, the leaves and roots being eaten in mistake for celery and parsnips respectively. Nine suffered from convulsions and became insensible; one died in five minutes, a second in a quarter of an hour, a third in an hour, and a fourth a few minutes later, while two more died during the next few days.
Cornevin says that this plant causes the poisoning of animals every year—they eat it willingly, showing an enfeebled instinct owing to domestication. The plant is poisonous in all its parts, the root being the most toxic, and drying does not destroy the toxic property. Cornevin gives the following quantities of the fresh root as necessary to poison various animals:—
| Horse | 0·100 | per cent. of the live weight. |
| Ox | 0·125 | „ „ „ |
| Sheep | 0·200 | „ „ „ |
| Pig | 0·150 | „ „ „ |
| Rabbit | 2·000 | „ „ „ |
Holmes described Oenanthe crocata as the most dangerous and virulently poisonous of all our native plants (Pharm. Jour., 1902).
Other species of Oenanthe are also poisonous in a less degree—e.g. O. fistulosa L., and O. Phellandrium Lamk.
Toxic Principle. Poehl (1895) obtained from the root of this species an amorphous neutral product which he designated Oenanthotoxin. The latest investigation is that by Tutin, who examined entire dried plants collected in early spring, and the experiments confirmed the conclusion arrived at by Poehl, that the toxic principle is a neutral resin. A dark-coloured, viscid resin, insoluble in water, and equal to 3 per cent. of the weight of the plant, was extracted, and it is stated that the neutral portions of the petroleum and ether extracts of this resin represent the toxic principle of the plant. As there is no evidence of the homogeneity of this product, and it is probably complex in character, it was given no name or formula. The fact that it has poisonous properties was ascertained by administering the various products to guinea pigs per os.
Symptoms. In poisoning by O. crocata the symptoms generally appear very quickly, and in serious cases death may follow in from one hour to a few hours. In Tutin’s experiments on guinea pigs the extracts referred to above rendered the animal hypersensitive in two to four hours, while marked convulsions, with trismus soon appeared; the heart-beat became very noticeably slow and the convulsions persisted until death ensued. There is great restlessness, difficult breathing, convulsions, loss of sensation, blindness and stupefaction (Müller); Lander says the symptoms recall hemlock poisoning, with the addition of green fœtid diarrhœa.