THE development of new methods of chemical analysis brings often in its train the discovery of new facts and the opening up of new fields of investigation. This is particularly true of biochemistry, where the accurate estimation of small quantities of substances in biological material may be of fundamental importance. There can be little question that the rapid progress in biochemical achievement owes much to the invention of micro-chemical methods of analysis applicable to biological material. Micro-Diffusion Analysis and Volumetric Error By Prof. Edward J. Conway. Pp. xiii + 306. (London: Crosby Lockwood and Son, Ltd., 1939.) 25s. net.