The first observations on the nature of the fluorescent material in fungus-infected hairs was reported by Felsher,1 who found it to be a water-soluble indicator substance. Recently efforts have been made to investigate the chemical and physical characteristics of the fluorescent material in hairs infected with Microsporum audouini.2 One of us (E. S. B.) participated in this prior work,2 in which the fluorescent substance in M.-audouini-infected hairs was found by spectrographic means to have a wide distinct band with maximum at 4902 A. A tentative chemical formula of the fluorescent substance was obtained by means of infrared absorption spectra, showing it to be a protein small polypeptide molecule with definite molecular groups. This has led to the concept that the fluorescent substance is a by-product of protein metabolism, probably from the melanin fraction of hair protein.
Attention was focused on the hairs in