So far we have been concerned with the urolagnic rather than the coprolagnic variety of scatalogical symbolism. Although the two are sometimes associated there is no necessary connection, and most usually there is no tendency for the one to involve the other. Urolagnia is certainly much the more frequently found; the act of urination is far more apt to suggest erotically symbolical ideas than the idea of defecation. It is not difficult to understand why this should be so. The act of urination lends itself more easily to sexual symbolism; it is more intimately associated with the genital function; its repetition is necessary at more frequent intervals so that it is more in evidence; moreover, its product, unlike that of the act of defecation, is not offensive to the senses. Still coprolagnia occurs and not so very infrequently. Burton remarked that even the normal lover is affected by this feeling: "immo nec ipsum amicæ stercus foctet."[29] Of Caligula who, however, was scarcely sane, it was said "et quidem stercus uxoris degustavit."[30] In Parisian brothels (according to Taxil and others) provision is made for those who are sexually excited by the spectacle of the act of defecation (without reference to contact or odor) by means of a "tabouret de verre," from under the glass floor of which the spectacle of the defecating women may be closely observed. It may be added that the erotic nature of such a spectacle is referred to in the Marquis de Sade's novels. There is one motive for the existence of coprolagnia which must not be passed over, because it has doubtless frequently served as a mode of transition to what, taken by itself, may well seem the least æsthetically attractive of erotic symbols. I refer to the tendency of the nates to become a sexual fetich. The nates have in all ages and in all parts of the world been frequently regarded as one of the most æsthetically beautiful parts of the feminine body.[31] It is probable that on the basis of this entirely normal attraction more than one form of erotic symbolism is at all events in part supported. Dühren and others have considered that the æsthetic charm of the nates is one of the motives which prompt the desire to inflict flagellation on women. In the same way--certainly in some and probably in many cases--the sexual charm of the nates progressively extends to the anal region, to the act of defecation, and finally to the feces. In a case of Krafft-Ebing's (_Op. cit._, p. 183) the subject, when a child of 6, accidentally placed his hand in contact with the nates of the little girl who sat next to him in school, and experienced so great a pleasure in this contact that he frequently repeated it; when he was 10 a nursery governess, to gratify her own desires, placed his finger in her vagina; in adult life he developed urolagnic tendencies.