IN the four decades from the publication of the “Origin of Species” in 1859 to the end of the nineteenth century, evolution held the centre of the stage in biology. With the rediscovery and confirmation of the facts and theories of Mendelian inheritance in 1900, there followed a period of intensive study of variations and their modes of transmission. To a considerable extent the early work on mutations prepared the way for the rapid development of experimental methods in the study of heredity. In due course Mendelian theory became closely associated with modified concepts of muta tions and with certain aspects of chromosome structure and behaviour. It remains an interesting historical fact that during the first three decades of the twentieth century evolutionary concepts developed very little ; indeed, in some biological circles evolution was almost a taboo subject. The position may be accurately gauged by the general tone of Bateson's presidential address at the British Association's meeting in Australia in 1914, approximately in the middle of this period, and even by the following single sentence from this address: “It is no time to discuss the origin of the Mollusca or of Dicotyledons, while we are not even sure how it came to pass that Primula obconica has in twenty-five years produced its abundant new forms almost under our eyes”. A further change in biological thought has become evident during the past ten years. To a certain extent, there has been a move back in interest and emphasis from heredity to evolution, but advance is marked by the acceptance of new theories, while the old theories are in part strengthened and in part discarded.
The Modern Synthesis. By Dr. Julian Huxley. Pp. 645. (London: George Allen and Unwin, Ltd., 1942.) 25s. net.