In vivo ESR studies have been made on Wistar and Sprague-Dawley rats using travelling wave helices implanted in the left lobe of the liver. Tissue regenerates completely around the Teflon-enclosed turns of the coil and histological studies have shown that it is composed of liver cells and connective tissue. Electron spin resonance studies of this tissue in vitro reported by Commoner and Ternberg in 1961 have demonstrated that it exhibits the 'tissue radical' signal. The implanted coils have detected, in vivo, a three-line spectrum due to a strong concentration of 4-hydroxy- 2,2,6,6-tetramethylpiperidine-1-oxyl free radical ('tempol'), a nitroxide spin label, injected either intramuscularly, intraperitoneally or intravenously into the experimental animal immediately prior to the measurement. They have also detected, in vivo, a similar three-line spectrum due to 'spin-labelled chlorpromazine', a tranquillizing drug to which this nitroxide spin label has been attached, injected intramuscularly or intraperitoneally into the animal immediately prior o the measurement. Work is currently in progress to increase the in vivo sensitivity of the implanted helices by menas of improved coupling techniques and the use of a time-averaging computer.

Why modernize? Because chemistry is a science as well as a practical art. Because theory has a large place in a science. Because the theoretical aspect of chemistry is changing rapidly.The modern theories concerning atomic structure and valence, ionization, and acids, bases, and salts are complementary to each other. The advantage in teaching that may be derived from considering them as the framework for the course is discussed and illustrated. Implied changes in terminology are mentioned. The errors in several of the older concepts are referred to and the more satisfactory picture of the science presented by the newer ones is emphasized. Particularly important is the me of new ideas in explaining the oxidation-reduction reaction, complex-ion formation, hydrolysis, the function of hydrated ions. The Aston method of atomic weight determination is recommended.

This is a workbook providing explanations of-d drill inthe fundamentals of arithmetic, algebra, geometry, and trigonometry, with the major emphasis on algebra. It is the joint product of a professor of mathematics, a professor of physics, and a professor of educational psychology, each contributing his own point of view and his own experience. Its content is based upon: (1) first-hand experience with college freshmen, (2) actual analysis of the requirements of first courses in college mathematics, physics, and chemistry, and (3) research on frequency of errors anmug freshmen.The authors suggest three specific and valuable uses of this workbook: (1) supplementary material for fist-year college courses in mathematics, (2) preparation for college courses in physics or chemistry, and (3) a general review for high-school seniors. With the possible exception of the section on geometry, the book is self-sufficient, even to the point of providing space for the student's work. An Answer Key, on perforated sheets, is

This paper outlines Aston's mass-spectrographic procedure for determining the atomic weights of complex elements and suggests its suitability for presentation in the early part of the general chemistry course. DURING the past few years F. W. Aston has modified and extended his mass-spectrographic procedure in such a manner

An examination of current textbooks of general chemistry reveals that very little use is made in a fundamental way of the modern conceptions of atomic structure, valence, complete ionization of strong electrolytes, and of acids and bases. It is suggested that they should be made the basis of treatment rather than occasional additions to the established presentation. Some new terms and definitions which are implied by the conceptions are discussed.