It is obvious, then, that sympathy aided by the altruistic sentiment--sympathy in the common sense--tends to produce disinterested retributive emotions. When we to some extent identify, as it were, our feelings with those of our neighbour, we naturally look upon any person who causes him pleasure or pain as the cause of our sympathetic pleasure or pain, and are apt to experience towards that person a retributive emotion similar in kind, if not always in degree, to the emotion which we feel when we are ourselves benefited or injured. In all animal species which possess altruistic sentiments in some form or other, we may be sure to find sympathetic resentment as their accompaniment. {112} A mammalian mother is as hostile to the enemy of her young as to her own enemy. Among social animals whose gregarious instinct has developed into social affection,[6] sympathetic resentment is felt towards the enemy of any member of the group; they mutually defend each other, and this undoubtedly involves some degree of sympathetic anger. With reference to animals in confinement and domesticated animals, many striking instances of this emotion might be quoted, even in cases when injuries have been inflicted on members of different species to which they have become attached. Professor Romanes' terrier, "whenever or wherever he saw a man striking a dog, whether in the house, or outside, near at hand or at a distance, . . . . used to rush in to interfere, snarling and snapping in a most threatening way."[7] Darwin makes mention of a little American monkey in the Zoological Gardens of London which, when seeing a great baboon attack his friend, the keeper, rushed to the rescue and by screams and bites so distracted the baboon, that the man was able to escape.[8] The dog who flies at any one who strikes, or even touches, his master, is a very familiar instance of sympathetic resentment. The Rev. Charles Williams mentions a dog at Liverpool who saved a cat from the hands of some young ruffians who were maltreating it: he rushed in among the boys, barked furiously at them, terrified them into flight, and carried the cat off in his mouth, bleeding and almost senseless, to his kennel, where he laid it on the straw, and nursed it.[9] In man, sympathetic resentment begins at an early age. Professor Sully mentions a little boy under four who was indignant at any picture where an animal suffered.[10] [Footnote 6: The connection between social affection and the gregarious instinct will be discussed in a subsequent chapter.] [Footnote 7: Romanes, _Animal Intelligence_, p. 440.] [Footnote 8: Darwin, _Descent of Man_, p. 103. _Cf._ Fisher, in _Revue Scientifique_, xxxiii. 618. A curious instance of a terrier "avenging" the death of another terrier, his inseparable friend, is mentioned by Captain Medwin (_Angler in Wales_, ii. 162-164, 197, 216 _sq._).] [Footnote 9: Williams, _Dogs and their Ways_, p. 43.] [Footnote 10: Sully, _Studies of Childhood_, p. 250.]