[64] Several writers have found in the facts of primitive animal courtship the explanation of the connection between love and pain. Thus, Krafft-Ebing (_Psychopathia Sexualis_, English translation of tenth German edition, p. 80) briefly notes that outbreaks of sadism are possibly atavistic. Marro (_La Pubertà_, 1898, p. 219 et seq.) has some suggestive pages on this subject. It would appear that this explanation was vaguely outlined by Jäger. Laserre, in a Bordeaux thesis mentioned by Féré, has argued in the same sense. Féré (_L'Instinct Sexuel_, p. 134), on grounds that are scarcely sufficient, regards this explanation as merely a superficial analogy. But it is certainly not a complete explanation. [65] Schäfer (_Jahrbücher für Psychologie_, Bd. ii, p. 128, and quoted by Krafft-Ebing in _Psychopathia Sexualis_), in connection with a case in which sexual excitement was produced by the sight of battles or of paintings of them, remarks: "The pleasure of battle and murder is so predominantly an attribute of the male sex throughout the animal kingdom that there can be no question about the close connection between this side of the masculine character and male sexuality. I believe that I can show by observation that in men who are absolutely normal, mentally and physically, the first indefinite and incomprehensible precursors of sexual excitement may be induced by reading exciting scenes of chase and war. These give rise to unconscious longings for a kind of satisfaction in warlike games (wrestling, etc.) which express the fundamental sexual impulse to close and complete contact with a companion, with a secondary more or less clearly defined thought of conquest." Groos (_Spiele der Menschen_, 1899, p. 232) also thinks there is more or less truth in this suggestion of a subconscious sexual element in the playful wrestling combats of boys. Freud considers (_Drei Abhandlungen zur Sexualtheorie_, p. 49) that the tendency to sexual excitement through muscular activity in wrestling, etc., is one of the roots of sadism. I have been told of normal men who feel a conscious pleasure of this kind when lifted in games, as may happen, for instance, in football. It may be added that in some parts of the world the suitor has to throw the girl in a wrestling-bout in order to secure her hand. [66] A minor manifestation of this tendency, appearing even in quite normal and well-conditioned individuals, is the impulse among boys at and after puberty to take pleasure in persecuting and hurting lower animals or their own young companions. Some youths display a diabolical enjoyment and ingenuity in torturing sensitive juniors, and even a boy who is otherwise kindly and considerate may find enjoyment in deliberately mutilating a frog. In some cases, in boys and youths who have no true sadistic impulse and are not usually cruel, this infliction of torture on a lower animal produces an erection, though not necessarily any pleasant sexual sensations.