Take.. half a pound of bunacre, and make a Cake thereof
To make a Horse follow his Master, and find him out and Challenge him amongst never so many people.
Take a pound of Oat-Meal, and put to it a quarter of a pound of Honey and half a pound of bunacre, and make a Cake thereof, and put it into your Bosom next to your naked Skin, then run or labour yourself till you Sweat, then rub all your Sweat upon your Cake, then keep him fasting a day and a night, and give it him to eat, and when he hath eaten it, turn him loose, and he shall not only follow you, but also hunt and seek you out when he hath lost you or doth miss you, and though you be environed with never so many, yet he will find you out and know you, and when he cometh to you spit into his Mouth, and anoint his Tongue with your Spittle, and thus doing he will never forsake you.
By "An Experienced Farrier," found in The Horseman's Week-End Book.
Anyone tried it? Though of course, you do need to know what Bunacre is, and I haven't had any luck finding out so far.