UMBELLIFERÆ.
Cowbane or Water Hemlock (Cicuta virosa L.). This plant is undoubtedly exceedingly poisonous, and fatal cases have occurred in both man and farm live stock. It has been mistaken by man for parsley, celery or parsnip, with fatal results, many persons having succumbed to it. The rootstock is attractive to children on account of its sweetish taste. Pott says that either fresh or dry it is poisonous to all animals when only a small quantity is eaten, and often causes rapid death. Sheep and goats appear to be less readily affected than other domestic animals, and cattle to be most sensitive. The loss of eleven animals in Brittany was noted in the Veterinarian in 1877, and a number of cattle died in Ireland (Veterinary News, 1911), death in both cases being due to Cowbane. It is clearly dangerous to grazing animals which have easy access to it, especially if ordinary herbage is scarce. Hedrick (Canada) is quoted as stating that a piece of the root about the size of a walnut is sufficient to kill a cow in about fifteen minutes; and Müller says that the quantity of dried plant sufficient to kill a horse appears to be about 1 lb. According to Kanngiesser the mortality in human poisoning due to this plant amounts to 45 per cent. of the cases.
Toxic Principle. The poisonous character of Cowbane has not been fully investigated, and the toxic principles are given as the alkaloid Cicutine, with Oil of Cicuta, and Cicutoxine. The last is a bitter resinous substance classed by Cushny in the picrotoxin group; it occurs in the dry root to the extent of 3·5 per cent. The toxicity is stated to vary with season and climate; the rootstock is most poisonous in spring.
Symptoms. In man the yellow poisonous juice in the rhizome induces epileptic convulsions, followed by death. The cicutoxine gives acrid narcotic symptoms quickly followed by fatal results. The symptoms usually appear within two hours, and death ensues in half-an-hour to several hours. The symptoms which appear in an hour or so are given as loss of appetite, salivation, vomiting (in swine), nausea, colic (in horse), bloating (in cattle), diarrhœa, irregular pulse and heart, dilatation of pupils, rolling of eyeballs, vertigo, reeling in circles, twisting of neck, falling down, automatic movement of limbs, opening and shutting of mouth, and death, usually with convulsions, in from half an hour to an hour after first manifestation of symptoms.
For cattle, Lander gives hurried respiration, collection of froth at the mouth and nostrils, and tympanites. The limbs are extended and alternately stiffened and relaxed.
In his description of the symptoms Esser states that swallowing is difficult, the tongue is stiffened, there is salivation, and death takes place after loss of consciousness and convulsions.
REFERENCES.
[31], [73], [81], [123], [141], [151], [170], [190], [203], [205], [213], [233], [238].
Water Parsnip (Sium latifolium L.). The leaves and especially the root of this species are regarded as poisonous, and the plant is described as “poisonous” by Strasburger.
According to Müller the symptoms resemble those produced by Chaerophyllum (p. [40]). After eating the roots cows showed symptoms of excitement, leading, in some instances, very quickly to death. The milk, according to Cornevin, is of a disagreeable flavour.