Sentence:  The horse also, as if it had its own premonitions, refused to get on to those rickety planks, though the rest of the party had negotiated them safely. The <WSD>"sais</WSD>" (horse attendant), who had no such anxieties, crossed ahead of us and struggled for some minutes to drag the poor frightened animal, with myself on its back, across the chasm. 
Meaning of the word marked with <WSD> tags:  A groom, or servant with responsibility for the horses.