The =ruminants=, large and small, use their horns, and cattle their feet as well. In the absence of horns they still use the forehead, but much less effectively and usually only with the purpose of defence. The =dog= attacks with his teeth and the cat with her claws by preference, and uses the teeth as a secondary weapon. =Swine= use their tusks to rip or disembowel their adversary or victim. A very ticklish horse cannot bear to be touched on the flank or hind parts, without throwing the ear backward, glancing back, showing the white of the eye, and lifting the foot. But if this is mere excess of sensitiveness and begets no disposition to kick it is not viciousness. The vicious horse will in such cases bite or kick repeatedly and with well directed purpose. He will moreover show the movements of ears and eyes and attack his victim in the absence of any such excuse, the simple approach being a sufficient occasion. He will bite and strike with the fore feet at the same time, or he may strike out with one hind foot or with both at once. He may attack indiscriminately all who approach him, or reserve his ill-will for particular individuals, and then he often acts under a feeling of revenge for ill-usage from this individual or some one he conceives him to represent. In some cases viciousness is inherited and certain families have a bad reputation in this respect. It may be either a survival of the ancestral disposition of the wild horse, or it may be a trait developed by ill-usage of a team of more immediate ancestors. In other cases the habit is acquired by the individual himself, and in such cases it may be due to brutal treatment at the hands of man; to a continuous punishment of a high-spirited horse leading to resentment and retaliation; to acute pain in boils, abrasions or other sores in the root of the mane, or the shoulder, or the back, where pressed on by the collar or saddle; or to the generative excitement of mares in _heat_. In many such cases the vice lasts only during the persistence of the cause, in others it becomes permanent. The stallion is much more disposed to aggressive vice than the gelding. Whether we may consider the vice a disease or not, it becomes a habit engrained in the nature, the nerve centres tending to reproduce their habitual acts indefinitely, so that we may look on the condition as a psychosis which is too often incurable.