Light and Electron Microscope Studies on the Cells of the Labyrinth in the Green Gland of Cambarus Sp.

In the course of studying the distal portion of the crayfish nephron tubule (Beams, Anderson and Press, 1956) cytoplasmic inclusion bodies of unknown origin were encountered in the cells of the labyrinth with a peculiar fibrous or laminated internal structure. This paper deals primarily with an investigation of these

Pollen Germination in Relation to Group Size

In recent experiments involving the germination of the pollen grains of Vinca rosea, it was observed that relatively poor germination occurred in isolated grains and among those grains aggregated in small groups (Beams and King, 1944). These preliminary observations seemed to warrant a further study of this problem. Accordingly, experiments were designed to determine some of the effects of population density on the percentage germination of these cells

fects of Ultracentrifuging on Certain Cell Structures

Extremely great centrifugal forces may be obtained by the use of the air-driven ultracentrifuge developed by J. W. Beams and his associates. Such forces afford a means of testing the viscosity and relative specific gravity of many cell components. The authors have been able to establish the fact that the Nissl bodies of rat ganglion cells represent a definite material in the cell and are not the result of the action of the fixative used on homogeneous cytoplasm; likewise, for the Golgi material in the uterine gland cells of the guinea pig. In general the chromatin has been shown to be heavier than the non-chromatin materials of the nucleus of various animal and plant cells. In Paramecium the chromatin has been moved centrifugally and there is left in the usual position of the macronucleus an achromatic alveolar mass. In Arcella the chromidia are heavier than the cytoplasm and the karyosomes of the nuclei are displaced toward the centripetal pole

Electron Micrographs of the Pellicle of a Species of Euglena

Electron microscope studies on whole mounts of Euglena demonstrated that the pellicle was composed of alternate grooves and ridges which were orientated in a spiral and longitudinal direction with respect to the long axis of the animal (Saxe 1947; Groupe 1947). Wolkin and Palade (1953) have presented electron micrographs of sectioned Euglena and made brief reference to the pellicle. It is the purpose of this paper to present further details on the structure of the Euglena pellicle as seen in thinly sectioned material under the electron microscope

Determination of Newton's gravitational constant, G, with improved precision Status report, 1 Apr. - 30 Sep. 1965

Apparatus and techniques for laboratory determination of Newtonian gravitation constan