Sentence:  ... he gave him a note to Mr. Harmon, one of the head managers of Durham's— / “The <WSD>bearer</WSD>, Jurgis Rudkus, is a particular friend of mine, and I would like you to find him a good place ... 
Meaning of the word marked with <WSD> tags:  Someone who delivers a letter or message on behalf of another ("especially as referred to in the letter or message").