Read it through once

Yes, you are his sure victim: yet his work is not all to your hurt--only part of it; for he is like your family physician, who comes and cures the mumps, and leaves the scarlet-fever behind. If your man is a Lake-Borgne-relief theorist, for instance, he will exhale a cloud of deadly facts and statistics which will lay you out with that disease, sure; but at the same time he will cure you of any other of the five theories that may have previously got into your system.