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He said he peeled back the six layers of the cadaver's vaginal wall and found a sac structure between the fifth and sixth layers that housed grape-like clusters of erectile tissue.

The dissection took seven hours for the Poland-trained physician and anatomist, who said he was inspired by the first principles of medicine — "first you have to establish the anatomy.'' If confirmed by further investigation, he said, he hopes his finding will help rewrite anatomy books.

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