Se . posed Sa ak tll debmaatle OP. ek ee OE eee eee . * wewee Fae, The following pages list, in summary fashion, the lectures and symposia to be given at the 1967 AAAS Meeting. In previous and subsequent issues of Science, some of them are described in more detail, as are the research interests of institutions where tours are offered. 1000 bladder and kidney stones mainly from Britain (going AAAS INVITED LECTURES back to 1770), India, Indonesia, Spain, Thailand, and Tur- key have been examined by x-ray diffraction techniques. Frontiers of Science: Lecture I The results of these and other investigations are compared 26 December, evening. Speaker: Carroll M. Williams (Bussey Professor of Biology, Harvard University). Hormones, Genes, and Metamorphosis. One of the larger and more intractable mysteries of present-day biology is epitomized by the transformation of an egg into a full-fledged organism. What we witness is an orderly enlargement and diversification of the cellular community according to an individual-specific construction manual which the fertilized egg inherited from the previous generation. By analogy to microbial systems, differential gene repression and derepression are central to all present theories of cytodifferentiation. Moreover, we can state with assurance that the orderly diversification of the community of cells is under close-up as well as overall chemical control. Particularly illuminating are recent investigations of the metamorphosis of insects. Insects that metamorphose are especially interesting subjects because in them the formative processes continue long into the postembryonic period instead of being restricted to the period of embryonic development, as in most other animals. graphically, to see whether any conclusions can be drawn about the possible causes of stones, including the possibility of kidney stone formation as an occupational hazard. Results of a few interesting studies of gallstones are also given, Frontiers of Science: Lecture II 28 December, afternoon. Speaker: Roger Revelle (Center for Population Studies, Harvard University). Can the Poar Revolution? Countries Hans W. Singer (United Nations Industrial Development Organization). indications are that, by an apparently indirect mechanism, Philadelphia). flow of genetic information and its implementation by the synthetic centers of the cells. 27 December, afternoon. Speaker: Dame Kathleen Lonsdale, F.R.S. (Professor University College, London, W.C.1; President, British Association for the Advancement of Science). Some Studies of Human Stones. A general review is given of the occurrence of urinary calculi from historical and geographical standpoints, taking into consideration location, composition, and age distribu- tion. Some kinds of stones are dying out in some localities, others are on the increase, especially for certain groups of people. The various methods of determining composition are reviewed and comparative data given. The formation of a nucleus can be related to various causes of crystal growth and the reasons for subsequent development of the stone are considered, especially where the composition of the stone changes from time to time. Collections of nearly 8 DECEMBER 1967 27 December, evening. Speaker: Athelstan Spilhaus (President, Franklin Institute, The Experimental City. George Sarton Memorial Lecture 28 December, afternoon. Frontiers of Science: Lecture II of Crystallography, Scientific William Paddock (Consultant in Tropical Agricultural Development, Washington, D.C.). Distinguished Lecture these hormones play upon the chromosomes to control the the Panel Discussion. Athelstan Spilhaus, Chairman. E. A. Mason (Massachusetts Institute of Technology). The cellular events which comprise metamorphosis are tightly coupled to endocrine signals administered by two hormones—ecdysone and juvenile hormone—both of which have recently been identified and synthesized. Present Benefit from Speaker: Cyril Stanley Smith (Institute Professor, Massachusetts Institute of Technology). The Revival of Qualities, Corpuscles, and Phlogiston in the Modern Science of Materials. Views on the nature of materials will be traced from workshop discoveries, through the forms and elemental qualities of Greek philosophers, Paracelsian principles, Cartesian corpuscles, and phlogiston to the rigid molecular chemistry of the nineteenth century. Some of each of the old views seems to have been revived in today’s emphasis on properties based on the behavior of electrons within complex structures. Address of the Retiring President blo 28 December, evening. Speaker: Alfred Sherwood Romer (Alexander Agassiz Professor Emeritus of Zoology, Harvard University). Major Steps in Vertebrate Evolution, 1343