SPECIFIC GRANULES IN ATRIAL MUSCLE CELLS.

Large populations (up to 600/cell) of spherical, electron-opaque granules approximately 0.3 to 0.4 micro in diameter are characteristically found in muscle fibers of mammalian atria.

X-ray Diffraction Studies on Dysprosium at High Pressures.

Dysprosium has been studied at pressures up to about 160 kilobars, well above the transition reported near 50 kilobars by other workers. It shows no definite structural alteration from hexagonal close-packed structure throughout this range. It is suggested that the 50-kilobar transition is most likely electronic or magnetic in nature, or that the metal undergoes a hexagonal stacking rearrangement.

THE FINE STRUCTURE OF DIPLOCOCCUS PNEUMONIAE.

The fine structure of an unencapsulated strain of Diplococcus pneumoniae is described. A striking feature of these bacteria is an intracytoplasmic membrane system which appears to be an extension of septa of dividing bacteria. The possible function of these structures and their relationship to the plasma membrane and other types of intracytoplasmic membranes found in pneumococcus is discussed.

PORCINE CONTAGIOUS PLEUROPNEUMONIA. 3. INTERRELATIONSHIP OF HEMOPHILUS PLEUROPNEUMONIAE TO OTHER SPECIES OF HEMOPHILUS: NUTRITIONAL, METABOLIC, TRANSFORMATION, AND ELECTRON MICROSCOPY STUDIES.

Hemophilus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP) is an encapsulated organism that has the metabolic features of the parainfluenza group of Hemophilus in that it requires DPN but not hemin for growth. Its formation of nitrate reductase cytochrome a(1) and non-physiologically reducible cytochrome c(1) in the stationary phase, together with its requirement of electron transport through oxidases for growth are typical of non-hemin-requiring Hemophilus species. It has the closest genetic homology, judged from the capacity of its DNA to induce transformation to streptomycin resistance, with H.

A RADIOIODINATED AZO DYE WITH AFFINITY FOR AMYLOID: A PRELIMINARY REPORT.

Investigation was undertaken to produce a radioactive material with affinity for amyloid tissue. Studies of a number of major dyes using paraffin histological sections of an amyloid spleen as test material showed that the only compounds with marked affinity for amyloid were watersoluble disazo dyes of the type E<--D-->E, where D is usually benzidine, o-tolidine or o-dianisidine, and E is a naphthol or aminonaphthol sulfonic acid. Substitution of an amino or a hydroxyl group in position 1 of the naphthalene nucleus caused loss of staining affinity.

Crystal Structures of Titanium, Zirconium, and Hafnium at High Pressures.

At high pressures, as determined by x-ray analysis, titanium and zirconium metal have a distorted, body-centered-cubic structure. This phase persists on pressure release. The normal hexagonal close-packed structures are recovered when the metals are heated.

Crystal Structures Adopted by Black Phosphorus at High Pressures.

Black phosphorus undergoes two reversible structural transitions at high pressures. The first is to a structure of the type arsenic A7. This structure is transformed to a simple cubic structure at higher pressures.

Crystal Structures at High Pressures of Metallic Modifications of Compounds of Indium, Gallium, and Aluminum.

X-ray diffraction shows that the high-pressure modifications (at 22 to 130 kilobars) of the antimonides of indium, gallium, and aluminum are analogous to white tin. The arsenide and phosphide of indium transform to NaCl type. The transformation of these semiconductors to their metallic states is empirically related to their energy gap under normal conditions.

Crystal Structures at High Pressures of Metallic Modifications of Silicon and Germanium.

Studies of germanium and silicon by x-ray diffraction reveal that their crystal structure changes at high pressures from the semiconducting diamond-type structure to the metallic white tin structure, in analogy to the known "gray" to "white" transition in tin itself.

Formation of Diamond by Explosive Shock.

Samples of graphite have been recovered after exposure to explosive shocks of 300,000-atm estimated intensity. X-ray and electron-diffraction examinations prove the existence of diamond in this material. The mechanism proposed for the formation of diamond under these conditions is simple compression in the c-axis direction of the rhombohedral form of graphite.

Sodium- and potassium-sensitive glass electrodes for biological use.

Continuous, accurate recording in circulating fluids from a sodium and a potassium electrode is described. The Na electrode is capable of discriminating Delta[Na(+)] of less than 1 meq/lit. in 140 meq/lit.