PROF. GOLDSCHMIDT’S “Physiologische Theorie der Vererbung” was familiar to all serious students of genetics, and they will welcome the present book, in which the same ideas are developed in view of the last ten years5 work of the author and others. The University of Berkeley, California, is fortunate in having been able to add Prof. Goldschmidt to its already world-famous school of genetics, and English students of genetics will be grateful for this book in their own language. As an account of the genetics of developmental processes, it will prove indispensable. Among the most fascinating topics dealt with are the author’s own work on the development of the wings in the Vestigial’ and ‘truncate’ series of allelomorphs in Drosophila, where the wing is normal in its early development, and lysis sets in later on, sometimes only after pupation. Sueffert found that the ‘tails’ on the wings of Papilio podalirius were produced by a similar process, which in some related species is gene-controlled. Equally interesting is Kühn’s analysis, by genetical and physiological methods, of the determination of the wing pattern in Ephestia kuhniella, and those of Zeleny, Hersh, Harnly, Plunkett and others on the temperature co-efficients of growth-rates in mutant forms.Physiological Genetics By Prof. Richard Goldschmidt. (Mc Graw-Hill Publications in the Zoological Sciences.) Pp. ix+375. (New York and London: McGraw-Hill Book Co., Inc., 1938.) 24s.