Read it through once

“Now for Mr. Breckinridge,” he continued, buttoning up his coat as we came out into the frosty air. “Remember, Watson that though we have so homely a thing as a goose at one end of this chain, we have at the other a man who will certainly get seven years’ penal servitude unless we can establish his innocence. It is possible that our inquiry may but confirm his guilt; but, in any case, we have a line of investigation which has been missed by the police, and which a singular chance has placed in our hands. Let us follow it out to the bitter end. Faces to the south, then, and quick march!”