Proceedings of the Physiological Society

Abstract

A method for the fixation of smoked tracings. By C. J. WILKS.Department of Physiology, University of Bristol Among the other disadvantages of resin varnishes in the fixation of smoked tracings is the almost inevitable gloss finish which complicates photographic reproduction.Adequate fixation of smoked records may be combined with a matt finish with the use of a casein size made up in the following proportions: casein, 15 g; ammonia, 25 ml.; spirit, 100 ml.; water, 900 ml.The kymograph paper is first passed through a tank containing methylated spirit; when dry the tracing is passed once through the casein size.The mode of action of the preliminary spirit priming is not clear, but without it it has been found impossible to obtain good results. When dry, a tracing is matt and may be preserved without further treatment provided care is taken to prevent scratching; records are best stored flat, protected by layers of tissue paper. If there is no question of future photography, gentle polishing with a silk cloth gives a hard, slightly glossy appearance. The records are now fully permanent and may be stored without special precaution.Internal calorimetry-an automatic recorder. By J. GRAYSON and A. L. HAIGH. Department of Physiology, University of Bristol Internal calorimetry, evolved from Gibbs's heated thermocouple (1933), is a method for the measurement of thermal conductivity in solid organs. Its main applications have been to liver and brain blood-flow determinations. The thermal conductivity of living liver is about twice that of dead liver. It was at first claimed that conductivity increment (8k), was a linear function of blood flow (Grayson, 1952), but Linzell suggested (1953) that this might not be strictly true even in the liver. However, recent experiments on liver and brain in which venous outflow was measured directly and compared with Sk show clearly that, over a wide range of flow, the relation is approximately linear.