=Mouldy= or =musty= oats, or other grain or fodder have long been notorious for producing diuresis in horses with excessive elimination of phosphates, extreme emaciation, weakness and death. In other seasons, and probably because of a difference in the fungi or their products they have caused widespread enzootics of indigestion with paresis of stomach and bowels, and of the systemic muscles. Paraplegia is a common manifestation, suggesting lesions of the spinal cord, and in other cases there are general paresis, somnolence and delirium suggesting cerebral lesions, (Staggers). Gillespie records an enzootic of gastro-intestinal indigestion and tympany among the horses of a battery of artillery in Afghanistan from eating mouldy grass. Fröhner, Martin and Varnell have seen cases of poisoning by moulds without digestive, urinary or febrile troubles. Of =rusts= growing on grain crops there are two chief varieties; the =spring rust= (_uredo rubigo vera_) which commences as light yellow patches on the leaves and stems, which change to black as the fungus approaches maturity; and the =summer rust= (_uredo linearis_) which grows to a larger size and assumes a browner color. Each of these passes through an evolutionary cycle, the small preliminary patches (=uredo=) passing into the mature fungus (=puccinia rubigo vera= and =puccinia graminis=.) Then it must pass through an alternate generation on another family of plants before it can again grow on the gramineæ. =Bunt= produced by the _tilletia caries_ attacks the grasses and small grains. The growing seed (wheat especially) is changed into a black or olive colored powder, having a fishy odor. If the stems are attacked the leaves become pale, withered and dry. It can only be detected by carefully examining the individual seeds. Other forms of smut are the =ustilago carbo= and =ustilago maidis= the familiar black smuts of small grains and maize. These develop by preference in the growing seeds, but also in the stem and leaves. The _tilletia caries_ is as a rule more poisonous than the _ustilago_ the effects being mainly hyperthermia and paralysis. There is, however, a tendency to spasmodic contractions, and abortions, and dry gangrene will occur from smut. The author has seen a large herd of cattle attacked with gangrenous sores around the coronet, which were promptly stopped when the light, smutty ears of corn were no longer given. In other cases the hoof was in part separated from the quick and creaked when the animal walked.