The Legend:
In 1951, a 16-year-old boy whose body was covered in warts was largely healed, apparently by hypnosis... but it shouldn't have worked.
The boy's body, excepting his face, back of neck, and chest area, was completely covered by skin that had been overgrown by what appeared to be black warts, and had the texture and toughness of dry fingernails. His skin had very little elasticity, which meant it was always cracking and bleeding in the joints and chronically infected in these areas, leading to a horrible body odor. All attempts to alleviate or cure the condition had failed... and this is when Dr. A.A. Mason suggested that such cases often responded well to hypnosis. He was given permission to try.
On February 10, 1951, Dr. Mason hypnotized the boy in front of a meeting of medical experts, and told the boy that his left arm would heal and become normal skin; just the left arm was specified so that any change caused by the hyonosis would be obvious. Five days later, the black warty skin had become noticibly softer, and had begun to fall off the arm, exposing skin with a normal texture and color... and by the tenth day, the boy's left arm was clear of the bumpy skin from shoulder to wrist. The hypnosis was repeated several more times -- for his right arm, then both legs, and then his trunk -- and in the course of a few weeks the boys' body was 70% less warty than before, and the unpleasant odor had disappated. The boy was ecstatic, and the doctor was proud... but other medical experts were not so happy.
The boys' condition was caused by a genetic fault and, therefore, should not have been curable in the least. The evidence as it stood suggested the possibility that Dr. Mason had somehow changed the boys' genetic code by hypnosis to alter the boys' symptoms, a circumstance that all agreed was an impossibility; in addition, it was argued that if the hypnosis didn't cure the boy entirely of the bumpy legions, then the so-called hypnosis 'cure' was basically worthless... an accusation that ignored the fact, of course, that no other treatment had caused any improvement in the boy's condition previously. The case was argued back and forth a bit, and then quietly ignored until it fell into obscurity, no one being willing to investigate enough to determine how the boy was actually healed.
The question remains: did Dr. Mason successfully treat a genetic malady with hypnosis?

The Rest of the Story
Many times when I investigate these sorts of legends, I find that they are essentially wrong in the details reported... that they are not extraordinary when seen in their original light. Not so in this case; the legend is essentially correct in it's details... Dr. A.A. Mason did hypnotize a boy with an incurable genetic malady, and the boy did improve noticeably, and in a way that proved the hypnosis was the cause... and I may now know how it worked.
One detail not mentioned in the legend is the fact that one of the previous attempts to help the boy included a plastic surgeon transplanting skin from the boy's chest (with relatively normal skin) to the palm of one of his hands (which had warty skin). This was in the hope that the normal skin would settle in place and allow for eventual use of the hand. But as the tissue transplant healed and settled into place, the new clear skin started to change... and within one month had become just as black and bumpy as the tissue that had been removed from the boy's palm to start with. A second attempt was made at the same procedure with the same results; the new, clear skin transformed into warty skin after being moved to the boy's hands.
This is an important detail because it proves one thing: the only difference between the skin in the clear areas and the skin in the bumpy areas was in what was the skin was being supplied by the body at those areas. So the problem wasn't the boys' skin itself... it was how the skin was being supported and nourished.
Hypnosis cannot change a genetic code, but it can change how your body behaves, both at a conscious level and at an unconscious, or autonomic, level. What seems to have happened in the case of Dr. Mason's remarkable cure is that, when given the suggestion that parts of his body would clear up, the boys' hypnotized consciousness arranged for bumpy parts of his body to start receiving the same chemical nourishment and support that the clear parts of his body were receiving... and since it was already shown that the clear skin could be turned bumpy by the failed skin transplants to the boys' palms, it shouldn't be too hard to believe that the bumpy skin could then be converted to clear by changing the underlying system of support.
So, NO, Dr. Mason did not change the boy's genetic makeup... but YES, Dr. Mason did cure the boy's condition using hypnosis to change how the boy's body basically treated the skin from the inside, a remarkable result that should have been investigated further but never was.

Sources:

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