A person who spends a few decades learning to recognize disease and the rest of his/her life learning the art of healing its sufferers. Some still prefer to call this a science. They are the ones who usually fail to heal best, for scepticism--the sceptre in the hands of science--is the greatest anti-placebo. As Hippocrates said: "Life is short, and the Art long; the occasion fleeting; experience fallacious, and judgment difficult."
The Hippocratic Oath
(in its original form)
I swear by Apollo the physician and Aesculapius, and Health, and All-heal, and all the gods and goddesses, that, according to my ability and judgment,
I will keep this Oath and this stipulation--to reckon him who taught me this Art equally dear to me as my parents, to share my substance with him, and relieve his necessities if required; to look upon his offspring in the same footing as my own brothers, and to teach them this art, if they shall wish to learn it, without fee or stipulation; and that by precept, lecture, and every other mode of instruction,
I will impart a knowledge of the Art to my own sons, and those of my teachers, and to disciples bound by a stipulation and oath according to the law of medicine, but to none others.
I will follow that system of regimen which, according to my ability and judgement, I consider for the benefit of my patients(it is interesting to note the current Siamese twin case in the UK), and abstain from whatever is deleterious and mischievous.
I will give no deadly medicine to any one if asked, nor suggest any such counsel; and in like manner I will not give to a woman a pessary to produce abortion. With purity and with holiness I will pass my life and practice my Art.
I will not cut persons labouring under the stone, but will leave this to be done by men who are practitioners of this work. Into whatever houses I enter, I will go into them for the benefit of the sick, and will abstain from every voluntary act of mischief and corruption; and, further, from the seduction of females or males, of freemen and slaves. Whatever, in connection with my professional service, or not in connection with it, I see or hear, in the life of men, which ought not to be spoken of abroad,
I will not divulge, as reckoning that all such should be kept secret. While I continue to keep this Oath unviolated, may it be granted to me to enjoy life and the practice of the art, respected by all men, in all times. But should I trespass and violate this Oath, may the reverse be my lot.