Health of the Food and Drug Administration in Rockville, Maryland. Either or both of them are authors of 12 of the 53 papers. The volume illustrates in historical fashion the uses of the knowledge of ultrasonic biophysics as well the experimental difficulties that have limited more rapid advance of knowledge in the field. The material is catalogued into three groupings. Part 1 contains papers dealing with the ultrasonic propagation properties of biological materials. Part 2 covers interaction mechanisms at the macromolecular and cellular levels of biological structure. Part 3 contains mechanism studies at the tissue and organ levels of structure. In this last section it is shown that there are three mechanisms whereby ultrasonic radiation damages tissues. At lower intensities and long-time durations ofexposure, the lesions are produced by a thermal mechanism. At high intensities and short-time durations , cavitation is believed to be the mechanism responsible for lesions. At intermediate dosages, lesions are formed by a mechanical mechanism which is thus far not well understood. Ultrasonic Biophysics is highly recommended for those who wish to learn not only about the interaction of ultrasonic energy with living systems but also about the evolution, experimental techniques, and current limits of knowledge of this branch of science. Raymond M. Fish, Ph.D., M.D. University of Chicago Great Scientists Speak Again. By Richard M. Eakin. Berkeley: University of California Press, 1975. Pp. viii+119. $2.65. The author of this remarkably successful book found dissatisfaction with his lectures in general biology ("Zoology 10") until he started to impersonate great biologists. This book is a revised version of the full lectures illustrated with sketches and slides used by six "speakers": William Harvey, William Beaumont, Hans Spemann, Gregor Mendel, Louis Pasteur, and Charles Darwin, all dressed in their period costumes, beards, wigs, and the like. During their 1974 presentations these lectures deservedly received world wide publicity and this book similarly deserves to be read by all educators in the life sciences. Although the author had no formal schooling in dramatic art, he clearly possesses considerable acting ability which he did not utilize prior to the experiment as recorded in this book. The idea is a most excellent one and constitutes an object lesson to all lecturers: Never neglect the basic tricks which should be part ofevery lecture. The fancy costumes are a bit extreme but lecturers should regularly use well-timed jokes, odd colloquialisms, and whatever necessary to dispel monotony and various stages of sleep always evident in the "captive" members of our audiences. These tricks are all highlighted in this highly entertaining and informative book. However, as the masterful introduction to Mendelian genetics express most eloquently, the principal appeal as well as indispensable ingredient of a lecture firmly remains its intellectual content. Jacobus W. Mostert, M.D. University of Chicago Perspectives in Biology and Medicine · Spring 1977 | 463 ...