This is a convulsive disease, arising from a disordered condition of the brain and spinal cord. It comes on suddenly, when the horse is out of doors, or even in the stable. The face, neck, and limbs, are seized with convulsions when the animal is standing; the eyelids wink, and the eyes roll about, the jaws champ, and the poor creature presents a pitiable spectacle. When he falls the convulsions continue, the limbs are plunged about, and the jaws are so fiercely moved that the tongue is often badly lacerated by the teeth; sometimes the animal moans or screams.

There is no remedy for this disease, and in the great majority of cases the horse should be destroyed, as it is dangerous to work him. If he falls during the attack, the head should be held down on the ground, to prevent it being damaged during the struggles. Cold water may be dashed on the face, and the mouth washed out with it. Great attention should be paid to the diet.