praised by Chrysippus, the famous philosopher, for masturbating in the market-place.  The more strenuous Romans, at all events as exemplified by Juvenal and Martial, condemned masturbation more vigorously.[347] Aretaeus, without alluding to masturbation, dwells on the tonic effects of retaining the semen; but, on the other hand, Galen regarded the retention of semen as injurious, and advocated its frequent expulsion, a point of view which tended to justify masturbation.  In classical days, doubtless, masturbation and all other forms of the auto-erotic impulse were comparatively rare.  So much scope was allowed in early adult age for homosexual and later for heterosexual relationships that any excessive or morbid development of solitary self-indulgence could seldom occur.  The case was altered when Christian ideals became prominent.  Christian morality strongly proscribed sexual relationships except under certain specified conditions.  It is true that Christianity discouraged all sexual manifestations, and that therefore its ban fell equally on masturbation, but, obviously, masturbation lay at the weakest line of defence against the assaults of the flesh; it was there that resistance would most readily yield.  Christianity thus probably led to a considerable increase of masturbation.  The attention which the theologians devoted to its manifestations clearly bears witness to their magnitude.  It is noteworthy that Mohammedan theologians regarded masturbation as a Christian vice.  In Islam both doctrine and practice tended to encourage sexual relationships, and not much attention was paid to masturbation, nor even any severe reprobation directed against it.  Omer Haleby remarks that certain theologians of Islam are inclined to consider the practice of masturbation in vogue among Christians as allowable to devout Mussulmans when alone on a journey; he himself regards this as a practice good neither for soul nor body (seminal emissions during sleep providing all necessary relief); should, however, a Mussulman fall into this error, God is merciful![348]

In Theodore’s Penitential of the seventh century, forty days’ penance is prescribed for masturbation.  Aquinas condemned masturbation as worse than fornication, though less heinous than other sexual offences against Nature; in opposition, also, to those who believed that distillatio usually takes place without pleasure, he observed that it was often caused by sexual emotion, and should, therefore, always be mentioned to the confessor.  Liguori also regarded masturbation as a graver sin than fornication, and even said that distillatio, if voluntary and with notable physical commotion, is without doubt a mortal sin, for in such a case it is the beginning of a pollution.  On the other hand, some theologians have thought that distillatio may be permitted, even if there is some commotion, so long as it has not been voluntarily procured, and Caramuel, who has been described as a theological