But there is a further group of cases, and a very important group, on account of the light it throws on the essential nature of these phenomena, and that is the group in which the thought or the spectacle of pain acts as a sexual stimulant, without the subject identifying himself clearly either with the inflicter or the sufferer of the pain. Such cases are sometimes classed as sadistic; but this is incorrect, for they might just as truly be called masochistic. The term algolagnia might properly be applied to them (and Eulenburg now classes them as "ideal algolagnia"), for they reveal an undifferentiated connection between sexual excitement and pain not developed into either active or passive participation. Such feelings may arise sporadically in persons in whom no sadistic or masochistic perversion can be said to exist, though they usually appear in individuals of neurotic temperament. Casanova describes an instance of this association which came immediately under his own eyes at the torture and execution of Damiens in 1757.[129] W.G. Stearns knew a man (having masturbated and had intercourse to excess) who desired to see his wife delivered of a child, and finally became impotent without this idea. He witnessed many deliveries and especially obtained voluptuous gratification at the delivery of a primipara when the suffering was greatest.[130] A very trifling episode may, however, suffice. In one case known to me a man, neither sadistic nor masochistic in his tendencies, when sitting looking out of his window saw a spider come out of its hole to capture and infold a fly which had just been caught in its web; as he watched the process he became conscious of a powerful erection, an occurrence which had never taken place under such circumstances before.[131] Under favoring conditions some incident of this kind at an early age may exert a decisive influence on the sexual life. Tambroni, of Ferrara, records the case of a boy of 11 who first felt voluptuous emotions on seeing in an illustrated journal the picture of a man trampling on his daughter; ever afterward he was obliged to evoke this image in masturbation or coitus.[132] An instructive case has been recorded by Féré. In this case a lady of neurotic heredity on one side, and herself liable to hysteria, experienced her first sexual crisis at the age of 13, not long after menstruation had become established, and when she had just recovered from an attack of chorea. Her old nurse, who had remained in the service of the family, had a ne'er-do-well son who had disappeared for some years and had just now suddenly returned and thrown himself, crying and sobbing, at the knees of his mother, who thrust him away. The young girl accidentally witnessed this scene. The cries and the sobs provoked in her a sexual excitement she had never experienced before. She rushed away in surprise to the next room, where, however, she could still hear the sobs, and soon she was overcome by a sexual orgasm.