Applied to the skin it is a strong irritant causing rapid and painful vesication.
"The Medicinal Plants of the Philippines"
T. H. Pardo de Tavera
Still more remarkable are the cases of vesication produced in hypnotized subjects by means of suggestion.
"Essay on the Creative Imagination"
Th. Ribot
In cases of recent wounds unattended by inflammation, it may be applied freely; but when inflammation has come on, too severe an application of the caustic induces vesication of the surrounding skin, and the edges of the eschar may in this manner also be loosened and removed.
"An Essay on the Application of the Lunar Caustic in the Cure of Certain Wounds and Ulcers"
John Higginbottom