Reference for Niddah 127:25

סירגה ליום עשרים וארבעה לא קבעה לה וסת

the law is different.<span class="x" onmousemove="('comment',' From that dealt with by Rab. In the former case, the first of the dates under discussion might well be added to the similar dates in the previous months and hence could not be counted as the first in the arithmetical progression. In the case dealt with by Rab, however, either the first of the dates under discussion was one on which the woman observed a discharge for the very first time, or the woman was one who had never before had a settled period or one whose settled period was on a day other than the first of those under discussion. The first day, therefore, may well be counted as one of the three days that establish a settled period. ');">²³</span>

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