The common brake or bracken fern, Pteris aquilina, has been considered responsible for the poisoning of many horses and cattle. Many cases have been reported in England and Germany, and some well-authenticated cases in the United States. Very little has been learned experimentally of fern poisoning, but there seems to be little question that it has been the cause of many deaths. The symptoms are said to be temperature higher than normal, loss of appetite, bloody discharges from mouth, nose, and bowels, and great depression followed by coma and death. Some authors say that the urine is colored by blood. It is thought by some that the disease known as "red water" in the northwestern United States and Canada is caused by eating ferns.
SORGHUM POISONING.
Under certain conditions sorghum contains enough hydrocyanic acid to make it exceedingly dangerous to cattle. These cases of poisoning most commonly occur when cattle are pastured upon the young plant or upon a field where the crop has been cut and is making a second growth. Conditions of drought make the sorghum especially dangerous. There is some reason to think that the frosted second growth is particularly rich in hydrocyanic acid. The cases of poisoning occur when animals are grazed upon the plant, but not from the harvested crop or from silage. If cattle are grazed on sorghum or sorghum stubble they should at first be under constant observation and should be removed as soon as any signs of illness appear. Similar precautions should be used in grazing kafir.
CORNSTALK DISEASE.
Considerable losses of cattle have occurred when they were turned upon cornfields in the fall. Deaths come very suddenly and there is no opportunity to apply remedies. It has been thought that these fatalities, like those from sorghum, were caused by hydrocyanic acid, but there is good reason to think that this is not true, and at the present time there is no accepted explanation of this disease, although there seems to be no doubt that it is connected in some way with the condition of the corn. Whether a given field is poisonous or not can only be determined by experiment, and the wise farmer will keep his cattle under close observation when they are first turned into a cornfield.
WATER HEMLOCK (CICUTA).
This plant, growing in wet places by ditches and along creeks, is the most poisonous of North American plants. The root is the poisonous part, and cattle generally get it when it is plowed up or washed out by high water. Sometimes they pull it up, for the plant occasionally grows out into ditches so that the whole plant will be taken in grazing. The most marked symptoms of Cicuta poisoning are the violent convulsions, which remind one of the effect of strychnin.
Treatment.—Little can be done in the way of treatment. The logical thing is to attempt to control the convulsions by means of morphia, but in view of the fact that the stomach can not be emptied, the prognosis is not good, and most cases die.
LARKSPURS.
The larkspurs are a source of heavy loss to cattle owners in the higher ranges of the West. There are a number of species, growing at altitudes from 4,000 feet to timber line, and all are poisonous. A few cases of poisoning by larkspurs have been reported in the eastern United States, but most of the losses are confined to the West, both because larkspurs grow there in greater profusion and because cattle are grazed in that region on the open ranges. The losses are confined to cattle, for sheep and horses can graze on larkspur with no resulting harm. Most of the larkspur losses occur in the spring and early summer, as the plants lose their toxicity after maturing.