“Bone Magic” was a ritual used in the 17th century to tame unruly horses. I first came upon it in From The Days that We have Seen by George Ewart Evans:

Of the Bone Magic
Kill a frog or toad. Leave it on a whitethorn bush overnight. Bury in an anthill. Under the light of a full moon, dig it up and—watching it carefully, never glancing away—take the skeleton to a running stream. Throw it into the water, and watch until the crotch bone floats back, against the current. When dry, crush it into a powder and mix with oil. Dip your finger in it and wipe it on the horse’s tongue, his nostrils, his chin and chest. “Then the horse is your servant, you can do what you like with him.”