Talmud zu Niddah 2:12

[Ye that inflame yourselves among the terebinths]⁶⁹The Biblical verse is inserted by H.—hence the Sages declared: A man may not put his hand to his membrum. There are three [instances of abuse by] the hand and in all three [the hand merits] amputation:⁷⁰Cf. Shab. 108b (Sonc. ed., p. 529). The hand that is put to the membrum let it be cut off! The hand that is put to the eye let it be cut off! The hand that is put to the vein for blood-letting let it be cut off! ‘The hand that is put to the membrum let it be cut off!’ Because it causes sexual excitement. ‘The hand that is put to the eye, let it be cut off!’ Because it leads to blindness.⁷¹Unclean hands, especially before they are washed in the morning, cause ‘infection’. ‘The hand that is put to the vein for blood-letting let it be cut off!’ Because it leads to death.