Hiranyakeshishrautasutra 7.3.1.p1.4

7.3.1.p1.4

etayoḥ somārambhānuguṇatvādavyavadhāyakatvameveti vadanti | pavamāneṣṭyavyavahitottarameva
caturdaśyāṃ paśvostantreṇottaravedikaraṇāntaṃ kṛtvā parvaṇi paśū tantreṇa kṛtvā yajanīye'hani
somārambhaṃ kuryāt | athavā pavamāneṣṭyavyavahitottaraṃ caturdaśyāmiva tantreṇa paśū kṛtvā
parvaṇi somārambhaṃ kuryāt | athavā caturdaśyāmevaindrāgnapaśoruttaravedikaraṇāntaṃ kṛtvā
parvaṇyaindrāgneneṣṭvā'nantaraparvaṇa upavasathe'hanyāśvinapaśoruttaravedikaraṇāntaṃ kṛtvā parvaṇyāśvineneṣṭvā tṛtīye parvaṇi somārambhaṃ kuryāt | somārambhātprāgutpatyarthaṃ tūṣṇīmagnihotrahomāḥ kāryā iti prayogakramatrayamavyavadhāyakatvavādimate somapūrvādhāne'gnīṣomīyeṇa
savanīyena vā sahopālambhatvamapi pakṣe | asminnarthe jñāpakamagre vakṣyate | nākṛtāyāṃ
prakṛtau vikṛtiḥ kāryetyayaṃ niyamastu yathā pavamāneṣṭipūrvabhāvitvaviṣaye na bhavati tathā
prāyaścittapaśupūrvabhāvitvaviṣaye'pi neti jñeyam | na ca somapūrvādhāne vicchinnasomapīthasya na bhavati | darśapūrṇamāsārambhaṃ vinā prāyaścittapaśvārambhāsaṃbhavāt
nākṛtāyāṃ prakṛtau vikṛtiriti niyamasya jāgarūkatvāditi vācyam | prāyaścittapaśvoḥ somānuguṇatvena somavattadārambhe'pi bādhakābhāvāt | satyāṃ somapīthecchāyāṃ tanniroddhurabhāvācca | etena prāyaścittapaśvoḥ sāṃnāyyavikṛtitvātsāṃnāyyārambhaṃ
vinā tayorārambhāsaṃbhavena prāyaścittapaśvanuṣṭhānaṃ vinā somāsaṃbhavenānyonyāśrayaparihā
rārthaṃ kāpeyapakṣamāśritya pūrvaṃ sāṃnāyyamanantaraṃ prāyaścittapaśū iti keṣāṃcidukti
parāstā | sarvathā'pi tāvatsiddhaṃ vicchinnasomapīthasyānālabdhatrātyapaśorna soma iti