I read this anecdote a while ago; anyone recognize it?

Statistics has been intruding into disciplines for a while now; remaking and improving them as it expands. However, not everyone takes readily to change.

Back in the late 1800's, medical science was advancing rapidly with new surgical techniques that became available after several Americans discovered and popularized the anaesthetic properties of ether. At the new Johns Hopkins Medical School, an established physician presented one of the latest procedures to students and practitioners.

At the end of the talk, one of the students asked whether the eminent doctor had conducted randomized trials to ascertain the success of the procedure.

"May I remind the student that lives hang in the balance. If, as you suggest, I had tested this procedure, half my patients would have died!", thundered the impugned doctor.

"Which half?" replied the snarky student.