'The Influences of Language on Medicine', by J. Z. Young, is reproduced by permission of the Editor of The Lancet.
'Communication of Thought in Ancient Greece', by T. B. L. Webster, is an abridged version of a paper read at the Copenhagen Congress for Classical Studies, to be published in the proceedings of that Congress.
'The Experimental Study of Speech', by D. B. Fry, was first published in the magazine Nature and is reproduced by courtesy of the Editors.
Acknowledgements are due to Dr Hallowell Davis, Dr Murray L. Barr and Dr M. Haggar for permission to use Figs. 1 and 2 (opposite page 30) from Doubt and Certainty in Science by Professor J. Z. Young ( Clarendon Press); to Dr N. Tinbergen and Messrs Methuen & Company for permission to use Figs. 3 and 4 on page 34, from Social Behaviour in Animals; to C. R. Ribbands and Messrs Jarrold's Ltd. for permission to reproduce Figs. 5 and 6 on pages 34 and 38 from The Behaviour and Social Life of the Honey Bee; to the Editors of The American Journal of Psychology for permission to reproduce Fig. 4 on page 163.