It was clearly one of the hazards of urban living in early modern London that, if the door of your house offered even the shallowest of entryways, offering partial concealment from the street, someone might avail themselves of this, and in the absence of public toilets, unload on your doorstep.
The astrologer John Lilly lived in a house with an advertisement on the wall outside, which proclaimed it to be the house of Merlinus Verax, the Truth-telling Merline. But one of the stories told in mockery of Lilly (being out-prognosticated by a dun cow, incapable of foreseeing that a whore will pick his pocket, etc.) was a much-repeated tale of a countryman, robbed in London, who was advised to consult Lilly (for astrologers would describe thieves to allow their clients to reclaim stolen goods). In this yarn, the doorstep of Lilly’s well-advertised house proves to have been defiled with excrement. When Lilly answered the door, he forgets his proper role and exclaimed: ‘If he did but know who did him that nasty trick, he would make them Examples to all such Roagues so long as they liv’d; Nay, quoth the Countreyman, if he cannot tell who beshit his door, he can as well be hang’d as tell me who had my Purse’ (Lil-lies Lamentations, or Englands feigned Prophet Discovered, p. 6-7).
Lilly forgot himself. He had also forgotten that there was a useful recourse for any householder so offended, a piece of sympathetic magic given in Jean Baptiste van Helmont’s A ternary of paradoxes the magnetick cure of wounds, nativity of tartar in wine, image of God in man / written originally by Joh. Bapt. Van Helmont and translated, illustrated and amplified by Walter Charleton.
“Hath any one with his excrements defiled the threshold of thy door, and thou intendest to prohibit that nastiness for the future, do but lay a red-hot iron upon the excrement, and the immodest sloven shall, in a very short space, grow scabby on his buttocks; the fire torrifying the excrement, and by dorsal Magnetism driving the acrimony of the burning, into his impudent anus. Perchance, you will object, that this action is Satanical, in regard the end of it is revenge, and the laesion of the party, which offended us; but assuredly, the abuse of such powers depends on the liberty of mans will, and yet the use is no whit the less natural.”
I love the expression ‘impudent anus’, and the dignified riposte to the view that this constitutes taking a Satanical revenge: this is just natural magic, which could be abused, but not in this case.