In a minor degree, not amounting to a complete perversion of the sexual instinct, this sentiment of abnegation, the desire to be even physically subjected to the adored woman, cannot be regarded as abnormal. More than two centuries before Krafft-Ebing appeared, Robert Burton, who was no mean psychologist, dilated on the fact that love is a kind of slavery. "They are commonly slaves," he wrote of lovers, "captives, voluntary servants; _amator amicæ mancipium_, as Castilio terms him; his mistress's servant, her drudge, prisoner, bondman, what not?"[90] Before Burton's time the legend of the erotic servitude of Aristotle was widely spread in Europe, and pictures exist of the venerable philosopher on all fours ridden by a woman with a whip.[91] In classic times various masochistic phenomena are noted with approval by Ovid. It has been pointed out by Moll[92] that there are traces of masochistic feeling in some of Goethe's poems, especially "Lilis Park" and "Erwin und Elmire." Similar traces have been found in the poems of Heine, Platen, Hamerling, and many other poets.[93] The poetry of the people is also said to contain many such traces. It may, indeed, be said that passion in its more lyric exaltations almost necessarily involves some resort to masochistic expression. A popular lady novelist in a novel written many years ago represents her hero, a robust soldier, imploring the lady of his love, in a moment of passionate exaltation, to trample on him, certainly without any wish to suggest sexual perversion. If it is true that the Antonio of Otway's _Venice Preserved_ is a caricature of Shaftesbury, then it would appear that one of the greatest of English statesmen was supposed to exhibit very pronounced and characteristic masochistic tendencies; and in more recent days masochistic expressions have been noted as occurring in the love-letters of so emphatically virile a statesman as Bismarck.