The suggestion of treating flat warts by the internal administration of mercury was first made by Dr. Charles J. White1 in 1915. This method of treatment was tried on the supposition that warts were caused by some as yet undiscovered protozoon. In his first paper White reported seven cases and four additional cases were reported in a subsequent communication. All of the eleven cases, except one, showed a most favorable response at the end of a few weeks to the internal use of some form of mercury. Four of White's patients were adults, the ages of the others varying from 7 to 14 years. In addition to the internal medication, some of the patients were also treated locally by salicylic acid or other remedy.
The disease in question is often spoken of as verruca plana juvenilis, though it is by no means confined to juvenile patients. It generally appears