ה דבי ר' ישמעאל תנא (ויקרא טו, כו) כמשכב נדתה יהיה לה מקיש משכבה לה מה היא אית לה טהרה במקוה אף משכבה נמי אית לה טהרה במקוה לאפוקי כלי חרס דלית ליה טהרה במקוה מתיב ר' אילעא מפץ במת מנין
5 Rather said R. Papa, This is its meaning: The midras of an earthen vessel is clean, whilst contact therewith defiles it; but [in the case of a vessel] of wood, both its midras and its touch are unclean; while a boat of the Jordan is clean, in agreement with our Tanna; R. Jose said: A ship too is unclean, in accordance with Hananiah. Now, how do we know that the midras of an earthen vessel is clean? — Said Hezekiah, Because Scripture saith, and whosoever toucheth his bed.<span class="x" onmousemove="('comment',' Lev. XV, 5. 'His bed' denotes anything upon which the zab has lain, and this passage teaches the law of midras. ');"><sup>17</sup></span> this assimilates 'his bed' to himself [the <i>zab</i>]: just as he can be cleansed in a mikweh,<span class="x" onmousemove="('comment',' V. Glos. ');"><sup>18</sup></span> so can 'his bed' be cleansed in a mikweh. The School of R. Ishmael taught: It shall be unto her as the bed of her impurity [<i>niddah</i>]:<span class="x" onmousemove="('comment',' Ibid. 26, q.v. ');"><sup>19</sup></span> this assimilates her bed to herself: just as she can be cleansed in a mikweh, so can 'her bed' be cleansed in a mikweh, thus excluding earthen vessels, which cannot be cleansed in a mikweh.<span class="x" onmousemove="('comment',' This is deduced from Lev. XI, 33, q.v. Since they cannot be cleansed, they cannot become unclean in the first place through the midras of a zab. ');"><sup>20</sup></span> R. Ela raised an objection: How do we know that a [reed] mat [is susceptible to defilement] through the dead?