THYMELACEÆ.
Mezereon (Daphne Mezereum L.) and Spurge Laurel (D. Laureola L.). Both of these species are acrid and poisonous, and cases of the death of horses due to the spurge laurel are recorded by Lander. In general, however, animals will not eat the plants, and indeed, in one of the cases mentioned by Lander the dried leaves were administered for worms. Should they touch these plants most animals would probably refuse them on account of their bitter taste. The berries are tempting to children, and Pratt says “Death has resulted from eating but a few of these berries (D. Mezereum); and Dr. Christison relates a case of a child, in Edinburgh, who died from eating them, while another is recorded by Linnæus of a young lady to whom twelve of the berries were given as a medicine in intermittent fever, and who soon died in consequence of their corrosive poison. Four berries produced thirst, sense of heat in the mouth and throat, and also fever, in a man who ate them; and they are proved to be poisonous to dogs and foxes.” Blyth states that 30 grammes (1 oz.) of the powdered bark is a lethal dose for a horse, but smaller doses of the fresh leaves may be deadly (Pammel).
Toxic Principle. All parts of these plants are acrid and poisonous, especially the bark and berries. They contain the bitter, astringent, and poisonous glucoside Daphnin (C30H34O19—or C15H160_9 according to Van Rijn), an acrid resin (Mezerein), and a vesicating fatty oil. (Pott remarks that Daphnin is believed to be harmless, but that Mezerein has poisonous effects.) Drying does not destroy the poisonous property.
Symptoms. The Daphnes are severely purgative, cause burning in the mouth and throat, and in severe cases have narcotic effects and give rise to convulsions.
Lander gives the symptoms as intense colic, constipation, followed by dysentery and copious evacuations of fæces streaked with mucus, blood, and intestinal epithelium. Drowsiness between the spasms.
According to Müller there is inflammation of the stomach and intestines (with colic, vomiting, severe diarrhœa, passing of blood), inflammation of the kidneys (with strangury, bloody urination), and in many cases nervous symptoms (weakness, giddiness, and convulsions).
In a case observed by Lander, in the horse, there was abdominal pain, staggering gait, anxious countenance, laboured breathing, pulse 80, temperature 103·2° F., bowels normal. On the following day there was excessive purgation, pulse 120, temperature 104·2° F., and death occurred at mid-day.
REFERENCES.
[73], [76], [81], [130], [141], [170], [190], [203], [213], [216], [240].