Photo-Reduction of Fluorescent Substances by Ferrous Ions

Abstract

DR. K. WEBER¹ has recently published a note on experiments which he connects with the results published previously by me². There is, however, not much relation between his experiments and my investigations, as may be clear from the following remarks. Dr. Weber seems to be unaware of the fact that by the method which I described it is only possible to reduce fluorescent substances, and then only when they are in a suitable state to exhibit fluorescence. Indeed, his own failure to reduce dyestuffs such as neutral red and Nile blue, which he has reported recently³, can be attributed mainly to the fact that these dyestuffs are non-fluorescent in aqueous solution.