If the sacrifice is injured from the Yagur-veda side, let him offer a libation in the Dakshina fire, saying, Bhuvah, Svâhâ! Thus does he bind together and heal, by means of the essence and the power of the Yagus verses themselves, whatever break the Yagus sacrifice may have suffered.

In plain words: If a mistake happens in the Yajur Veda part of the ritual, the priest should pour an offering into the southern fire, saying 'Bhuvah, Svaha!' This uses the power of the Yajur verses to repair the mistake.