Niddah

actual terumah which is subject to the same restrictions as hallowed things where only 'leaning' might be assumed;  for we learnt: If a zab  and a clean person were unloading an ass or loading it, if the load was heavy  [the latter] is unclean; if it was light  he is clean and in either case  he is regarded as clean  [even if he is] of the members of the Synagogue  but as unclean  in respect of terumah,  and 'unconsecrated food that is in a condition of tebel in respect of the dough-offering' is regarded as dough-offering.  But have we not learnt:  A woman who is a tebulath yom  may  knead her dough and cut off from it its dough-offering  and put it on an inverted basket of palm-twigs or on a board,  and then  bring it close [to the major portion of the dough] and designate it [as dough-offering;  this procedure being permitted] because the uncleanness of the dough  is only of the third grade,  and the third grade is regarded as clean in common food.  Now if you were to maintain that 'common food that is in a condition of tebel in respect of the dough-offering is regarded as dough-offering' [the objection would arise:] Did she not in fact convey uncleanness to it?  — Said Abaye: In regard to any object,  that conveys certain uncleanness to common food, uncleanness has been imposed as a preventive measure, even in a doubtful case, where common food that is in a condition of tebel in respect of the dough-offering is concerned,  but in regard to the woman who is a tebulath yom, since she does not convey certain uncleanness to common food,  no uncleanness has been imposed as a preventive measure in a doubtful case where common food that is in a condition of tebel in respect of the dough-offering is concerned.  But is there not the case of the retrospective uncleanness of the twenty-four hours [preceding the observation] of a menstrual flow which  conveys certain uncleanness to common food and in connection with which, nevertheless, no uncleanness has been imposed as a preventive measure in a case of doubt  where common food that is in a condition of tebel in respect of the dough-offering is concerned;  for has not the Master said, 'R. Samuel son of R. Isaac accepted from him this [teaching, and explained it] as applying to common food that was prepared under conditions of hallowed things and not to common food that was prepared in conditions of terumah'?  — In the former case  no terumah is kneaded up with the common food  but in the latter case terumah  is kneaded up with the dough.  And if you prefer I might reply: Leave out of the question the retrospective uncleanness of the twenty-four hours, since it is merely a Rabbinical measure. MISHNAH. R. ELIEZER RULED: IN THE CASE OF FOUR CLASSES OF WOMEN IT SUFFICES [FOR THEM TO RECKON] THEIR [PERIOD OF UNCLEANNESS FROM] THE TIME [OF THEIR DISCOVERING OF THE FLOW]: A VIRGIN,  A WOMAN IN PREGNANCY,  A NURSING WOMAN,  AND AN OLD WOMAN.  R. JOSHUA SAID: I HAVE ONLY HEARD [THE RULING  APPLIED TO] A VIRGIN.