I had to live to sixty-three
To see the crow in the cherry tree.
I watched a programme about placebos last night. It seems they work by getting the brain to release the appropriate chemicals. And the thing that triggers the response is the patient's faith in the procedure and the practitioner. Faith in the practitioner operates even if and when the patient knows they're getting a sugar-pill. The better the doctor's bedside manner the deeper the faith.
The programme didn't go any further than this but it looks as if we're well on the way to understanding the efficacy of faith-healing and Bach's flower remedies.