God intervened in daily life, especially if worshipped. Saints such as Bede and Hilda performed miracles, especially ones of curing. Their spirits could be contacted through their relics, which rested at the altars of churches. When someone was said to have the devil in him, people took it quite literally. A real Jack Frost nipped noses and fingers and made the ground too hard to work. Little people, elves, trolls, and fairies inhabited the fears and imaginings of people. The forest was the mysterious home of spirits. People prayed to God to help them in their troubles and from the work of the devil. Since natural causes of events were unknown, people attributed events to wills like their own. Illness was thought to be caused by demons. People hung charms around their neck for cure and treatments of magic and herbs were given. Some had hallucinogenic effects, which were probably useful for pain. For instance, the remedy for "mental vacancy and folly" was a drink of "fennel, agrimony, cockle, and marche". Blood- letting by leeches and cautery were used for most maladies, which were thought to be caused by imbalance of the four bodily humors: sanguine, phlegmatic, choleric, and melancholic. These four humors reflected the four basic elements air, water, fire, and earth. Blood was hot and moist like air; phlegm was cold and moist like water; choler or yellow bile was hot and dry like fire; and melancholy or black bile was cold and dry like earth. Bede had explained that when blood predominates, it makes people joyful, glad, sociable, laughing, and talking a great deal. Phlegm renders them slow, sleepy, and forgetful. Red cholic makes them thin, though eating much, swift, bold, wrathful, and agile. Black cholic makes them serious of settled disposition, even sad. To relieve brain pressure and/or maybe to exorcise evil spirits, holes were made in skulls by a drill with a metal tip that was caused to turn back and forth by a strap wrapped around a wooden handle. A king's daughter Edith inspired a cult of holy wells, whose waters were thought to alleviate eye conditions. Warmth and rest were also used for illness. Agrimony boiled in milk was thought to relieve impotence in men. It was known that the liver casted out impurities in the blood. The stages of fetal growth were known. The soul was not thought to enter a fetus until after the third month, so presumably abortions within three months were allowable.