A constitutional timidity tends constantly to increase unless the animal is judiciously accustomed to the object of terror. The horse once scared, seems to become more and more watchful for other objects of dread, and even inclined to bolt from such as are common and of every day occurrence. Cattle and sheep attacked by the gadfly (œstrus) flee in great terror, and this dread is communicated from animal to animal so that the whole herd or flock is suddenly panic-stricken. The bellow of the ox attacked and the erection of its tail is the signal for every other within reach to join the stampede. These panics are associated with the instinct of these races toward a gregarious life; they mass together for protection and they learn to heed the slightest indication of approaching danger. This instinct grows more powerful by constant exercise, and is most marked in those genera which have the least natural means of protection. Hence, of all animals sheep are most easily panic-stricken, and once affected, they move in mass, one following its fellow, without object, without definite direction or destination, and without consideration of the other dangers they are to meet. Hence, if one sheep jumps over the parapet of a bridge to certain destruction, the whole flock speedily follows. If one leaps over a fallen tree into a snow bank, all at once follow suit and pile above each other in one suffocating, perishing mass. While this condition is hereditary in gregarious families, it is essentially a psychosis in those animals that have been often scared until they are continually on the watch for objects of fear. _Treatment._ In the case of horses, the best course is to make the animal familiar with the object of dread; let him look at it, approach it slowly, smell it, feel it with his lips. Never turn away his eyes from it and drive him off, as that confirms the impression of dread, and the object retains ever after its dreaded appearance. In this way timid colts become gradually fearless of umbrellas, city sights, street cars, large vans, flags, music, locomotives and the like,—they become, in the expressive language of the horseman, _road-wise_. A paddock or yard beside a railroad will soon accustom a timid horse to the cars, and so with other things, experience will remove apprehension.