Reference for Shabbat 191:1
הא ברברבי והא בזוטרי אמר רב אסי שונין כלי חרס שיעורו בכונס משקה ולא אמרו מוציא משקה אלא לענין גיסטרא בלבד מאי טעמא אמר מר זוטרא בריה דרב נחמן לפי שאין אומרים הבא גיסטרא לגיסטרא
the one refers to large ones, the other to small ones.<span class="x" onmousemove="('comment',' Rashi: in the case of large ones the greater portion must be broken, but for small ones a hole large enough for a pomegranate to fall out is sufficient. Ri: In the case of large ones a hole large enough etc., is required, but in the case of small ones, where this may be considerably more than half if the greater portion thereof is broken it is no longer a utensil. ');"><sup>1</sup></span> R. Assi said, They [the Tannaim] learnt. As for an earthen vessel, its standard is [a hole] large enough to admit a liquid, while [one merely] sufficient to allow a liquid to run out was mentioned only in connection with a mutilated vessel.<span class="x" onmousemove="('comment',' v. p. 457, n. 4. ');"><sup>2</sup></span>