short interval from that of the Saṃhitā, for it appears to have been known to the writer of the Aitareya Āraṇyaka, while its author, Çākalya, is older than both Yāska, who quotes him, and Çaunaka, composer of the Rigveda Prātiçākhya, which is based on the Pada text.
The importance of the latter as a criterion of the authenticity of verses in the Rigveda is indicated by the following fact. There are six verses in the Rigveda [1] not analysed in the Pada text, but only given there over again in the Saṃhitā form. This shows that Çākalya did not acknowledge them as truly Rigvedic, a view justified by internal evidence. This group of six, which is doubtless exhaustive, stands midway between old additions which Çākalya recognised as canonical, and the new appendages called Khilas, which never gained admission into the Pada text in any form.
A further measure for preserving the sacred text from alteration with still greater certainty was soon taken in the form of the Krama-pāṭha, or "step-text." This is old, for it, like the Pada-pāṭha, is already known to the author of the Aitareya Āraṇyaka, Here every word of the Pada text occurs twice, being connected both with that which precedes and that which follows. Thus the first four words, if represented by a, b, c, d, would be read as ab, bc, cd. The Jaṭā-pāṭha, or "woven-text," in its turn based on the Krama-pāṭha, states each of its combinations three times, the second time in reversed order (ab, ba, ab; bc, cb, bc). The climax of complication is reached in the Ghana-pāṭha, in which the order is ab, ba, abc, cba, abc; bc, cb, bcd, &c.
The Prāticākhyas may also be regarded as safeguards
