No one doubts--certainly not I--that the mind exercises a powerful influence over the body.

From the beginning of time, the sorcerer, the interpreter of dreams, the fortune-teller, the charlatan, the quack, the wild medicine-man, the educated physician, the mesmerist, and the hypnotist have made use of the client's imagination to help them in their work.

They have all recognized the potency and availability of that force.

Physicians cure many patients with a bread pill; they know that where the disease is only a fancy, the patient's confidence in the doctor will make the bread pill effective.
Faith in the doctor.

Perhaps that is the entire thing.