Adaptation in Micro-Organisms: Third Symposium of the Society for General Microbiology Held at the Royal Institution, London, April 1953.

Arranged in 15 chapters, with discussion immediately following the text of each lecture, this volume gives adequate coverage to a specialized field that has been intensively developed in the past 10 years. From the different types of evidence advanced on mechanisms of adaptation it is clear that extreme views held only a few years ago by the so-called genetical school and the environmental school are being modified to meet in a more rational area. Mutational selection and environmental modification of phenotypic expression of growth form and metabolism are not mutually exclusive conditions, but often complementary, as is well brought out in discussions by G. Pontecorvo, S. Spiegelman, and C. N. Hinshelwood. In a symposium on so restricted a topic some overlapping may be expected, but, on the whole, the organizers are to be complimented on their selections. The chapters by E. P. Abraham (The Development of Drug Resistance in Microorganisms);