Although experiments in the training of pigs show that they have rather remarkable intellectual capacities, the most human feature in their mental organization is found in the keen sympathy which they exhibit with the sufferings of their own kind and the willingness with which they encounter danger in protecting their comrades. It usually requires close observation for the naturalist to determine the existence of this motive among the other wild or domesticated mammals. In fact, the traces of it are very slight indeed, and are generally to be attributed to the care of parents for offspring or of the males for their harem--a disposition which, though akin to the defence of the kind, is nevertheless of a special and peculiar nature. Even among our domestic dogs, whose sympathies have been developed in a remarkable degree and who will sacrifice their lives to defend or rescue the human beings with whom they are familiar, there appears to be but little disposition to support members of their species who may be assailed. With pigs, however, as is well known to all those who have observed their habits, the characteristic cry of distress of their fellows proves very exciting and stimulates all the adults, both male and female, who hear it to hasten in defence of their kinsmen. It is a noteworthy fact that while most other animals when in danger utter no distinct or continuous cry, the pig gives voice in a vociferous and insistent manner, as if he had a right to expect the sympathy and help of his species. The cry goes with the custom of defence which in this species has attained a better foundation in the sympathetic motives than in any other mammal below the level of man. It is perhaps due to their relatively high intellectual organization that the excessively domesticated pigs are liable to suffer from attacks of mania. This is most commonly exhibited by the sows, which at times will destroy their young shortly after they are born. The sight of their progeny seems to infuriate them in a curious manner. One sow which I owned killed three successive litters; another fine animal of the Berkshire breed, a very amiable, indeed affectionate, creature, was carefully watched at the time she first bore young, precautions being taken to prevent her from harming them; she would willingly allow them to suckle, provided she did not see them, but the moment she laid her eyes upon them she was seized with the strange fury.