44. THE PRINCIPLES OF PHYSIOLOGY

By Prof. J. G. McKendrick, M.D. "It is a delightful and wonderfully comprehensive handling of a subject which, while of importance to all, does not readily lend itself to untechnical explanation. . . . Upon every page of it is stamped the impress of a creative imagination."—Glasgow Herald.

46. MATTER AND ENERGY

By F. Soddy, M.A., F.R.S. "Prof. Soddy has successfully accomplished the very difficult task of making physics of absorbing interest on popular lines."—Nature.

49. PSYCHOLOGY, THE STUDY OF BEHAVIOUR

By Prof. W. McDougall, F.R.S., M.B. "A happy example of the non-technical handling of an unwieldy science, suggesting rather than dogmatising. It should whet appetites for deeper study."—Christian World.

53. THE MAKING OF THE EARTH

By Prof. J. W. Gregory, F.R.S. (With 38 Maps and Figures.) "A fascinating little volume. . . . Among the many good things contained in the series this takes a high place."—The Athenæum.

57. THE HUMAN BODY

By A. Keith, M.D., LL.D., Conservator of Museum and Hunterian Professor, Royal College of Surgeons. (Illustrated.) "It literally makes the 'dry bones' to live. It will certainly take a high place among the classics of popular science."—Manchester Guardian.