COMPOSITÆ.
Tansy (Tanacetum vulgare L.). Live stock are most unlikely to eat this plant, as it is bitter and acrid. Cattle appear to have been poisoned by it in Germany, Kobert’s opinion being that death had resulted from tansy. There have also been many serious cases of human poisoning.
Toxic Principle. Tansy contains the bitter, volatile and poisonous Oil of Tansy.
Symptoms. Tansy Oil has been employed as an abortifacient, and produces convulsions, violent spasms, frequent and feeble pulse, and paralysis of the heart and lungs, inducing a condition similar to that observed in rabies.
Pammel cites cases of the action of the oil from the plant on dogs. According to Pott the tansy imparts a bitter taste to the milk of cows which eat it.
REFERENCES.
Ragwort (Senecio Jacobœa L.). No suspicion appears to have been focussed on Ragwort in Britain, but it must be recorded here as the cause in Canada of the Pictou cattle disease, or hepatic cirrhosis, a somewhat fatal disease which has caused much loss during the last few years. In New Zealand also the same disease has been experienced, and has caused considerable mortality among sheep. In one case sheep were closely pastured on about 4000 acres with the object of eradicating the too prevalent weed, but after a year losses ensued. Gilruth concluded that if the weed does not monopolise the ground, sheep may, with few exceptions, eat it daily without suffering ill effects. Cattle and horses avoided it when possible.
It may be remarked that in Britain feeding the young shoots off with sheep, which seem to like the plant, is regarded as the best plan of reducing Ragwort in grass land. So far there seems to be no record of injury from this cause.
In South Africa cirrhosis of the liver in cattle (locally termed Molteno cattle sickness) has been traced to S. latifolius, 8 to 10 lb. of which in daily feeds of 2 to 6 oz. caused death in about six weeks. Another species, S. Burchellii, is similarly poisonous, ½ lb. daily for four days having killed an ox on the fifth day; at Molteno half the quantity proved fatal. Both species are fatal to cattle and horses.
Toxic Principle. As regards S. Jacobœa nothing appears to be known as to any toxic principles, though an alkaloid has been isolated by Watt (1911), but not fully described. The South African S. latifolius, however, was examined at the Imperial Institute, and two new crystalline alkaloids were isolated—Senecifoline (C18H27O8N) and Senecifolidine (C18H25O7N)—1·20 per cent. being present in the plant before flowering and 0·49 per cent. after flowering.
Symptoms. As they may to some extent serve as a guide in relation to possible Ragwort poisoning in Britain the symptoms observed from poisoning by the South African species may be given: Severe and strained purging: fæces yellowish to dark brown; cows cease to give milk; abdominal pain, groaning; animal may go mad and charge anyone approaching, or lie with outstretched head, drooping ears, staring coat, and dull glaring eyes; death usual within three days from commencement of purging. The post-mortem shows an inflamed fourth stomach; hardened condition of the liver, often dull grey with spots in the interior; expanded gall bladder, with dull yellow viscid bile.
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Wild Lettuce (Lactuca sp.). Just how far the two species L. scariola L. and L. virosa L. are really poisonous is not clearly known, and it is probable that to be seriously harmful to farm live stock they would need to be ingested in considerable quantity, and this they never seem to be. They are certainly not actively poisonous, though Bailey and Gordon say that “we have been informed that this European plant—now a national pest—is sometimes eaten by cattle, on whom it has been observed to have had an injurious effect.”
Toxic Principle. Authorities differ as to the substances to which the toxic property, if any, is to be attributed. According to Ludwig the milky juice, known as Lactucarium, includes Lactucone, Lactucin, and Lactucic Acid, the second of these being the narcotic substance. Nearly half the weight of Lactucarium (a form of dried juice) consists of the tasteless inodorous Lactucone or Lactucerin (C14H22O), and the bitter taste is due to Lactupicrine, Lactucin and Lactucic Acid. In the leaves of L. virosa, Dymond found traces of Hyoscyamine or a similar substance (Jour. Chem. Soc., 1892, Vol. 61, p. 90).
Symptoms. Intoxication is produced similar to that caused by poppy heads; the narcotic effects are dominant (Cornevin).
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