It is probable that the phenomena just mentioned are due to confinement, idleness and ennui, and that they do not often happen in nature where an animal is kept busy seeking his food, fighting and avoiding his enemies, attending to his mate or mates, and meeting the various vicissitudes of his environment. It should be remembered, however, that the members of a wild species vary in intelligence and temperament, as humans do. There are morons and perverts among animals in the wild; but not being coddled by the normal members of the species, they have a poorer chance than has the subnormal human of surviving and of transmitting their peculiarities. Fear, ennui, loneliness and nostalgia, by affecting the minds of captive animals, react on their physical condition. Some animals have the fear of man bred in them. The young often show it from time of birth. This is especially common in animals that have survived for generations in proximity to man. It is one reason for their survival. The mother and father may have become tame and gentle in captivity and yet the young one may be a wild thing from birth. Such fear is sometimes uncontrollable, an apparently slight cause making the animal dash itself against the fence of the enclosure. It is not mere speculation to discuss the physical effects of the emotions on the animal body. It has been shown that fear, anger, and grief bring about distinct measurable physical changes. Dr. Corson-White has found that the red corpuscles are increased by over two million per cubic centimetre in the blood of a cat frightened by a dog barking at it. The amount of blood sugar is also increased. Such observations are suggestive in a consideration of the changes that may occur in a captive animal subjected to acute and chronic fear.