In discussion about alleged letter of Alexius Commenus, attention turned to some dubious relics, like for example milk of the Virgin Mary. Calvin wrote about it in his Treatise on Relics in following way:
With regard to the milk, there is not perhaps a town, a convent, or nunnery, where it is not shown in large or small quantities. Indeed, had the Virgin been a wet-nurse herwhole life, or a dairy, she could not have produced more than is shown as hers in various parts. How they obtained all this milk they do not say, and it is superfluous here to remark that there is no foundation in the Gospels for these foolish and blasphemous extravagances.
Here is an answer to the Calvin’s question where this milk comes from. A beautiful local legend trying to explain quite natural phenomena (similar Greek myth claims that the Milky Way was caused by milk spilt by Hera when suckling Heracles):
The moral is, never have preconvictions about relics, no matter how absurd they sound to your eyes. They may surprise you.