Magnets fascinate us because they act at a distance -- both attracting and repelling. Lodestone (the name literally means "leading stone") was so named for its navigational utility. There was a time when magnetism was consigned to inanimate things -- and then just mostly to iron. Ironically, magnetic navigation by birds and other animals appears to rely on magnetite.
As long as magnetism remains a mysterious force, it will find uses in medicine and alternative therapies. Discredited science and pseudo-science can die out and then return in vigor, once new discoveries occur. Such is the case for animal magnetism.
Around 1784, pre-revolutionary Paris was enthralled by Franz Mesmer, whose schtick was to pass magnets over people and cure them of alleged physical and mental ailments. Louis XVI (or his courtiers) was concerned enough to task the learned heads at the time to look into the matter. A Royal Commission included Antoine Lavoisier and Benjamin Franklin, among others. To make a long but interesting story short, the Royal Commission debunked Mesmer and he faded into near obscurity, leaving behind only the verb "to mesmerize." The whole story was brilliantly translated and retold by Stephen Jay Gould in his Bully For Brontosaurus.
Around 1845, Michael Faraday discovered that all matter responds to magnetic fields, albeit weakly and then only in the presence of very strong fields. Faraday named this remarkable property diamagnetism (though he did not explain its origins). Faraday's discovery briefly reenergized a belief in animal magnetism.
Faraday also discovered the paramagnetism of oxygen (he used soap bubbles filled with O2 rather than liquid oxygen). Faraday developed a theory that atmospheric oxygen is seasonally influenced by the earth's magnetic field via temperature. He later abandoned this brainchild.*
*Frank A.J.L. James, Michael Faraday: A Very Short Introduction, Oxford University Press (2010)