The Eleventh Symposium on Advances in Tracer Method­ ology was held in Boston on October 13-14, 1966. The sym­ posium, which was sponsored by the New England Nuclear Corporation, commemorated the tenth anniversary of the Corporation. The Symposia on Advances in Tracer Methodology, which have been held regularly since 1957, bring together research workers in a variety of disciplines who share an interest in radioactive tracers. The four volumes, this one representing the record of the Eleventh Symposium, provide a compact and readily available source of information-much of which was usually scattered throughout the scientific literature-of inter­ est to biochemists, pharmacologists, endocrinologists, and analysts for whom tracers have become an indispensable tool. The editor is especially grateful to Dr. Konrad Bloch, Harvard University, and Dr. Waldo E. Cohn, Oak Ridge National Laboratory, for chairing the sessions at the Eleventh Sym­ posium. The cooperation of the speakers is deeply appreCiated. In addition, a special bouquet to my secretary, Mrs. Edith Thompson, for her generous assistance in arranging the various symposia and the publication of the papers. S. R.

Springer Book Archives

Introductory Remarks by Chairman.- Labeled Compounds.- Recent Developments in Labeling by Catalytic Exchange-The Application of ?-Complex Theory to the Prediction of Isotopic Hydrogen Orientation in Molecules Labeled by Heterogeneous Techniques.- The Preparation of N-Methyl-C14-Labeled Drugs.- The Design of Criteria of Purity for Labeled Compounds.- Radiolysis of Binary Mixtures-A Study of the Radiation Chemistry of Methanol Using Labeled Molecules.- Analytical Techniques.- Tritium and Carbon-14 -by Oxygen Flask Combustion.- Thin-Layer Chromatography Radioassay: A Review.- Modification and Utilization of Isotope Fractionation Phenomena in Analytical Separations.- High-Resolution Autoradiography of H3-Estradiol with Unfixed, Unembedded 1. 0 ? Freeze-Dried Frozen Sections.- Radioautography as a Technique in Tracer Methodology.- Liquid Scintillation Counting: Automated Mathematical Fitting and Use of Channels Ratio Methods by Computer Program.- Applications of Labeled Compounds.- Methodology of Radiotracer Enzyme Assays.- The Use of Labeled Drugs in Psychopharmacology Research.- Application of Tracers to Quantitative Histochemical and Cytochemical Studies.- Application of Tracer Methodology to the Study of Bio-genic Amines.- Use of Chronically Labeled Animals in the Study of a "Metabolically Inert" Protein.- Recent Advances in the Double Isotope Derivative Analysis of Steroids.- Estimation of Specific Radioactivity of Steroids Biosynthesized from Labeled Precursors.- Continuous Radioactivity Monitoring of Perfusion in the Small Intestine of the Intact Animal.- Coated Charcoal Assay of Vitamins, Minerals, Hormones, and Their Binders.