in which leading scientists speak in a programme edited by Professor E. N. da C. Andrade , F.R.S. This week, What the Pharmacologist Does.' by J. H. Burn. m.d., F.R.S., Professor of Pharmacology in the University of Oxford; and ' The Photographic Film.' by E. R. Davies , O.B.E., Director of Research for a leading firm of photographic manufacturers