Moreover, it is evident that life in societies would be utterly impossible without a corresponding development of social feelings, and, especially, of a certain collective sense of justice growing to become a habit. If every individual were constantly abusing its personal advantages without the others interfering in favour of the wronged, no society--life would be possible. And feelings of justice develop, more or less, with all gregarious animals. Whatever the distance from which the swallows or the cranes come, each one returns to the nest it has built or repaired last year. If a lazy sparrow intends appropriating the nest which a comrade is building, or even steals from it a few sprays of straw, the group interferes against the lazy comrade; and it is evident that without such interference being the rule, no nesting associations of birds could exist. Separate groups of penguins have separate resting-places and separate fishing abodes, and do not fight for them. The droves of cattle in Australia have particular spots to which each group repairs to rest, and from which it never deviates; and so on.(28) We have any numbers of direct observations of the peace that prevails in the nesting associations of birds, the villages of the rodents, and the herds of grass-eaters; while, on the other side, we know of few sociable animals which so continually quarrel as the rats in our cellars do, or as the morses, which fight for the possession of a sunny place on the shore. Sociability thus puts a limit to physical struggle, and leaves room for the development of better moral feelings. The high development of parental love in all classes of animals, even with lions and tigers, is generally known. As to the young birds and mammals whom we continually see associating, sympathy--not love--attains a further development in their associations. Leaving aside the really touching facts of mutual attachment and compassion which have been recorded as regards domesticated animals and with animals kept in captivity, we have a number of well certified facts of compassion between wild animals at liberty. Max Perty and L. Buchner have given a number of such facts.(29) J.C. Wood's narrative of a weasel which came to pick up and to carry away an injured comrade enjoys a well-merited popularity.(30) So also the observation of Captain Stansbury on his journey to Utah which is quoted by Darwin; he saw a blind pelican which was fed, and well fed, by other pelicans upon fishes which had to be brought from a distance of thirty miles.(31) And when a herd of vicunas was hotly pursued by hunters, H.A. Weddell saw more than once during his journey to Bolivia and Peru, the strong males covering the retreat of the herd and lagging behind in order to protect the retreat. As to facts of compassion with wounded comrades, they are continually mentioned by all field zoologists. Such facts are quite natural. Compassion is a necessary outcome of social life.