Much of the discursive material that was circulating for a while in a non-redactive state was forgotten during the interval; what remained was in a precarious state. The Stammaim reclaimed it, complementing and integrating it. The luxurious and flowing texture of the Talmud is the achievement of the Stammaim; prior to them there were only short dialogues and comments strung along the Mishnah and Braithoth.
David Weiss Halivni, Midrash, Mishnah, and Gemara: The Jewish Predilection for Justified Law (Camridge, MA & London, UK: Harvard University Press, 1986), 79.