四分律行事鈔資持記 2.478

2.478

他部中，《十誦》。諸緣，並非意故。言斷解者，力窮疲頓，筋脈舒緩也。《善見》。彼又云：除髮爪及燥皮無精耳。

In the other schools: in the Daśādhyāya-vinaya, the various conditions are all because it was not intentional. 'Exhaustion and relaxation' means strength is spent in fatigue, and the sinews and vessels relax. In the Samantapāsādikā: it also says: 'Excepting hair, nails, and dry skin, there is no semen.'