In the horse this disease is due to feeding on grain containing the seeds of vetches, but in the ox to eating the green portions of the plants. Feeding has to be continued for at least a month to produce accidents.
The earliest symptoms consist in suppression of milk secretion, and somnolence. Nervous symptoms—from which alone the horse suffers—soon make their appearance. The neuro-muscular system is attacked. Interference with the nervous system is followed by inco-ordination of movement, and later by paraplegia of the hind quarters. Roaring is not noticeable, probably because the patients rarely move rapidly.
The lesions have been little studied, but appear to consist in congestion and infiltration of the meninges, cord, and roots of the lumbo-sacral plexus.
Treatment. If the animals are paralysed, treatment is rarely of value; otherwise it is sufficient to remove the cause and to administer purgatives and diuretics, with the object of eliminating toxic products. Recovery follows in three to four weeks.
Robinia pseudacacia.—The common locust tree is native in the central and eastern parts of the United States, and is extensively cultivated for ornamental purposes throughout the Union. The bark and leaves contain a powerful poison, and persons have been killed by eating these parts.
* Sophora secundiflora.—The beautiful bright-red beans of the frijo-lillo, or coral bean of southern and western Texas contain a powerfully poisonous alkaloid. The plant is said to have poisoned stock in Texas and in northern Mexico.
LINACEÆ (FLAX FAMILY).
Linum rigidum.—The large-flowered yellow flax is reported from Pecos Valley, Texas, as poisonous to sheep. An investigation made by the Bureau of Animal Industry, U.S.A., showed that the plant is poisonous.
Fig. 96.—Caper spurge (Euphorbia lathyris). a, Upper half of plant, one-third natural size; b, seed capsule, natural size.