Siliceous Shells of Protozoa

Carbon replicas of siliceous sponge spicules.

Magnetite dissolution in siliceous sediments

[1] Magnetite dissolution, and consequent loss of magnetization, is widely observed in reducing sedimentary environments, where the decrease in Eh-pH values with depth is driven by bacterially mediated degradation of organic carbon. We have observed low magnetizations in sediments with elevated pore water silica concentrations that arise from diagenesis of biogenic silica and/or silicic volcani...

Manual of Human Protozoa

may give an indication of the wide appeal which this book should have. These headings are: Significance of Permeability Studies; Methods of Studying Membrane Permeability; Equilibrium Conditions of Cells; Some Equations used in Permeability Studies; The Nature of the Process of Diffusion; The Structure of the Plasma Membrane; The Interpretation of Permeability Measurements; Permeability to Non-...

Mitochondria of Protozoa

A study of thin sections of Paramecium multimicronucleatum, Tetrahymena pyriformis, Tokophrya infusionum, and Amoeba proteus shows that the mitochondria in all these protozoa are similar in certain aspects of their fine structure to that described in metazoan cells. As in higher organisms the mitochondrion is surrounded by a double limiting membrane and contains protrusions directed inward from...

Non-siliceous anisotropic crystals in tuberculous salpingitis.

Attention has recently been drawn to the similarity between the histological picture of silicious granuloma and tuberculosis of proliferative type in the Fallopian tube of man (Roberts, 1947). In the differential diagnosis emphasis has been placed on the value of the polarizing microscope. The purpose of the present paper is to draw attention to the presence of doubly refractile, but non-silici...