Diac Chect Was one of teh Tuatha De Danann. He was a healing deity who slew his own son, Miach, out of jealousy for surpassinng his healing power. Since Dian could not re-attatch the arm of a King of the Tuatha De Danann after it was cut off in battle- and Miach accomplished it. After Miach's death it was said that 365 healing herbs - one for every human ailment - grew from his grave. His sister, Airmid, gathered the herbs and laid them in an outline shaped like a body, so that the healing knowledge could be passed down from grnereation to generation. But Dian scattered the herbs so that the knowledge of how to cure all ailments was lost to us.
The outcome of this story for the ancient Celts was the Brat Aitmeithe, a large peice of cloth cut into the shape of a human body. Stitches on it are pictures of herbs that are beneficial to each part of he body.