In forming the feminine, the letter ai is the substitute of the final word pūtaktu when the affix ṅīp is added.,
Thus पूतक्रतायी 'the wife of Putakratu'. This and the two succeeding sutras, are in a way more intimately connected with 4.1.48, in as much as the sense of the feminine words must be that of 'wife of', otherwise these sutras will not apply. Thus if the meaning is not that of 'wife of', the word पूतक्रतुः will be both masculine and feminine as well, meaning 'she by whom sacrifices (क्रतवः) are sanctified (पूताः)'.,