Into this enlarged kernel of pithy sayings of the oldest authorities, which may be characterized as the _Abot of Rabbi Akiba_, later _Tannaim_--Rabbi Meir, Rabbi Judah ha-Nasi, and others--interpolated additional sayings of the afore-mentioned Rabbis, and also typical utterances of their disciples, and of other well-known teachers. This accounts for the presence in _Abot_ of the body of maxims of the six generations of the school of Hillel, designated above as section B 1, and which was very properly introduce after the aphorisms of Hillel and of his contemporary, Shammai. The thread of tradition being interrupted by this interpolation, it was again taken up by the introduction of another body of Hillel's sayings (B 2), thus providing for a natural transition from Hillel to Jochanan ben Zakkai. Proof of the fact that section B is an addition is that in the _Abot de-Rabbi Natan_--which, as has been said above, is based on an older version of _Abot_ (14)--the sayings of Jochanan ben Zakkai follow immediately upon those of Shammai. The sayings of Judah ha-Nasi, the redactor of the _Mishnah_, and of Rabbi Gamaliel, his son, were undoubtedly added after the time of Judah. (14) See _supra_, p. 13, n. 9. Chapter III contains the sayings of authorities who were the predecessors of Judah, the first two having lived before the destruction of the second Temple. Chapter IV is made up of the dicta of a number of Rabbis who were contemporaries of Judah. These two chapters were, no doubt, inserted by Judah, the redactor of the _Mishnah_ as we virtually have it to-day. Evidence that Chapter IV is an addition to the original _Abot_ is that it has a number of aphorisms which are repetitions of some found in Chapters I and II. The greater part of Chapter V, as stated above, was a portion of the _Abot_ of Rabbi Akiba. Chapter VI, which is known as _The Chapter on the Acquisition of Torah_ (_Perek Kinyan Torah_), as _The External Teaching of the Abot_ (_Baraita de-Abot_) (15), as _The Chapter of Rabbi Meir_ (_Perek Rabbi Meir_) (16), and as _the External Teaching of Rabbi Meir_ (_Baraita de-Rabbi Meir_), is a supplement of the treatise _Abot_, as is claimed for it by its superscription, "the sages taught in the language of the _Mishnah_," a formula generally used in the _Talmud_ to introduce a _Baraita_. One of the authorities mentioned in it is Joshua ben Levi, a Palestinian _amora_ (an authority of the _Gemara_) who lived during the third century. This demonstrates the comparatively late date of the final redaction of this chapter. By the middle of the ninth century it formed a part of the treatise _Abot_. It was added to the prayer-book to be read on the sixth Sabbath of the period between Passover and the Festival of Weeks (_Shebuot_) (17).