* Claviceps purpurea.—This, the most common species of ergot, infests various species of native and cultivated grasses. It sometimes causes great losses of stock.
POISONING BY ERGOT OF RYE: ERGOTISM.
Causation. This form of poisoning is due to the presence of ergot in grain or forage.
Symptoms. The symptoms are seldom very marked. In mild cases pregnant females may abort; grave cases are indicated by local gangrene of the mucous membrane and gangrene of the extremities, particularly in poultry, in consequence of the constrictive action of the drug on the peripheral blood-vessels, on the vaso-motor centres, and on unstriated muscular fibres.
Treatment. The use of chloral and morphine has been suggested in this condition; but as the lesions when discovered are established and permanent, this treatment seems illusory. More is to be expected from preventive measures and the avoidance of ergotised food.
USTILAGINACEÆ (SMUT FAMILY).
Ustilago maydis.—The black powdery fungus known as corn smut is common throughout the corn-producing districts of the central United States, and is occasionally reported as being fatal to stock. Experiments made in Wisconsin and elsewhere show that it is not a very active poison when eaten in moderate quantity. When given in gradually increasing amounts up to 2 lbs., no effect was noted, but 4 lbs. on each of two successive days caused the sudden death of one cow. Since corn smut has been shown to be less fatal when wet, it seems probable that its physical and not its chemical character may be responsible for the death of cattle which have eaten it in considerable quantity.
Fig. 74.—Fly amanita (Amanita muscaria). a, Mature plant; b, top view of cap showing corky, patches—both one-half natural size.