After having rubbed the parts which were thus rendered in some degree insensible, with hard soap, he discovered, on the application of hot iron, that their insensibility was increased.

He then determined on again rubbing the parts with soap, and after that found that the hot iron not only occasioned no pain but that it actually did not burn the hair.
Being thus far satisfied, the Professor applied hard soap to his tongue until it became insensible to the heat of the iron; and having placed an ointment composed of soap mixed with a solution of alum upon it, burning oil did not burn it; while the oil remained on the tongue a slight hissing was heard, similar to that of hot iron when thrust into water; the oil soon cooled and might then be swallowed without danger.
Several scientific men have since repeated the experiments of Professor Sementini, but we would not recommend any except professionals to try the experiments.
Liquid storax is now used to anoint the tongue when red-hot irons are to be placed in the mouth.

It is claimed that with this alone a red-hot poker can be licked until it is cold.
Another formula is given by Griffin, as follows: 1 bar ivory soap, cut fine, 1 pound of brown sugar, 2 ounces liquid storax (not the gum).
Dissolve in hot water and add a wine-glassful of carbolic acid.

This is rubbed on all parts liable to come in contact with the hot articles.
After anointing the mouth with this solution rinse with strong vinegar.
No performer should attempt to bite off red-hot iron unless he has a good set of teeth.

A piece of hoop iron may be prepared by bending it back and forth at a point about one inch from the end, until the fragment is nearly broken off, or by cutting nearly through it with a cold chisel.