Philadelphia, May 2, 1907.
To the Editor:
—The increased efficiency of formaldehyd disinfection as applied at the present time by means of the formalin-permanganate method of evolving the gas has brought with it a new danger, uncertain, yet none the less real, in consequence of the fact that on several occasions at least, the mixture has been known to take fire spontaneously.During the winter of 1906-7 Dr. Courtland Y. White of Philadelphia, in connection with some disinfection work which he was doing for the Department of Health of the state of Pennsylvania, observed on three occasions that the mixture caught fire after the combination of the constituents had begun and the room had been closed. It was fortunate that the fact was discovered on one of these occasions, as the flame was so high as to endanger nearby articles in the room. Suspecting the possibility of impure ingredients, he