Small Spherules Research Articles

Observations on the structure and the nature of NR bodies found in the testes of bed-bug.

1. NR bodies show special affinity for neutral red. They are rounded or irregular in outline, measuring 0·25–12·5µ in diameter.2. In fixed preparations NR bodies appear as spherical and vacuolated structures.3. RNA is present in abundance in mature NR bodies, but while DNA is present in variable amount, the Feulgen technique shows that in their very young stage NR bodies are rich in DNA.4. Glycogen is absent from the NR bodies, but Hale's technique provides evidence that the hyaluronic acid type of polysaccharide is present in them.5. By Gomori's modified technique the presence of alkaline phosphatase in the NR body was demonstrated.6. The mature NR bodies multiply by a process of budding. Small buds or spherules rich in DNA infect fresh spermatogonial cells, the latter being converted into the ‘pathological cells’ of Hertig.

The Properties of Carbon Contacts

Microphone carbon has been produced by deposition of pyrolytic carbon films over the surfaces of small spherules of silica. The properties of contacts between these spherules are shown to be dependent on the structure and geometry of the carbon surface as determined by electron diffraction and microscopic studies. The graphite-like crystallites in pyrolytic carbon surfaces are more or less preferentially oriented with their basal planes parallel to the surface, and the contact properties depend systematically on the degree of orientation. This is explained in terms of the anisotropy in properties of these crystallites which are closely approximated by those of single crystal graphite which were determined. The contact resistance and its temperature coefficient and the ``burning voltage'' for carbon contacts are explicable on this basis. However, the microphonic sensitivity of carbon contacts is independent of the surface structure and depends only on the surface geometry.

The Formation of Black Carbon

Electron microscopic evidence is presented in support of the hypothesis that black carbon resulting from pyrolysis of gaseous hydrocarbons is produced through the intermediate formation of droplets of complex hydrocarbons. Electron diffraction studies further confirm this hypothesis if, as has been found for particles of carbon blacks, the droplets consist in part of graphitic nuclei arranged with their basal planes tangential to the droplet surface. The carbonization of small solid spherules of highly cross-linked organic polymers is described, and it is shown that the morphology of the carbonization products is wholly analogous to those for pyrolytic carbon and carbon blacks. It is suggested, therefore, that the formation of carbon by the carbonization of solids and by deposition from the gas phase occurs through similar mechanisms and that the two processes are simply two extremes in an infinite series of processes which are all fundamentally alike.

A Simple Direct Method for the Electron Microscopy of Peripheral Blood Cells

The need of the hematologist for methods applicable to the study of the cells of the peripheral blood with the electron microscope has been pressing. Almost a decade ago Wolpers and Ruska studied thrombocyte structure in relation to fibrin deposition. Wolpers, separately, devised a technic for the direct electron micrography of red blood corpuscles and their membranes. Replica or indirect studies of the red blood corpuscular surfaces were reported later by Barnes, Burton and Scott and by Jones. More recent direct observations include those of Claude and Fullam who, with the electron microscope, studied mitochondria isolated from lymphosarcoma cells of the rat. They brought evidence for an enveloping membrane as well as for small elements within the body of certain mitochondria. Reed and Reed studied erythrocytes from dog's blood with reference to patterned aggregates of hemoglobin and other components which varied with the rapidity of drying of the erythrocyte in vacuo. Fine granules, rough, fibroblast-like forms, and massed aggregates arising from coalescence of the smaller structures were observed. Hovanitz studied resting chromosomes obtained from nuclei of erythrocytes of the chicken. A definite spiral structure was present which may have represented a thread imbedded in a matrix. Appendages were seen with their attachment threads. When the chromosomes were dissolved in M NaCl and precipitated, anastomosing strands composed of minute particles about 50 millimicrons in diameter were produced. Claude, Porter and Pickets were able to obtain macrophages from tissue cultures of centrifuged blood of normal chickens after explanting small fragments of the buffy coat. Their micrograph (their Fig. 1) depicted only the cytoplasm of such a macrophage. Golgi bodies, mitochondria and the particulate components (microsomes) of the ground substance were well portrayed. Bessis and Bursteinstudied the progression of structural changes occurring in thrombocytes in vitro. After addition of anticoagulant, the blood was centrifuged and a drop of the supernatant fluid rich in thrombocytes was utilized for electron microscopy. Their numerous excellent micrographs depict the succeeding stages, classified as circulating forms, dendritic forms, transitional forms, and ultimately, expanded forms. Expansion of the platelet is preceded by pseudopodia formation. In a later series of investigations, Bessis' employed the shadow-casting technic and demonstrated that thrombocyte protoplasm presented numerous radiate fibrils and rarer arcuate forms. The fibrils were composed of small spherules (50 to 200 millimicrons in diameter) separated from one

Fusion of Carbon

IN the course of an investigation on the behaviour of the carbon arc in various gases at high pressure, carried out in apparatus provided by Imperial Chemical Industries Ltd., we have obtained large amounts of carbon in a fine state of division. In certain circumstances this carbon is deposited as graphite, all in the form of small spherules of about 0.02 mm. diameter or smaller, having a density 2.25. There seems to be little doubt that these spherules of graphite have been formed owing to the effect of surface tension, the carbon having persisted for a finite time in the molten state. The best yield was obtained at 90 atmospheres in hydrogen with an arc dissipating 20 kilowatts. The temperature of the positive crater at this pressure has not yet been determined. The surface brightness at 10.5 atmospheres was 2.18 times that of the arc at atmospheric pressure for the same wave-length, corresponding to an increase of brightness temperature of 460°. The increase in the thermodynamic temperature must be of the same order, so that the temperature was probably much higher at 90 atmospheres. Further investigations are necessary before the precise conditions under which the spherules are formed are established. The percentage of ash left after burning the carbon of the electrodes was 0.8, that from the carbon collected from the arc chamber less than 3 per cent. It is scarcely likely that this amount of fusible ash could cause the whole of the carbon to adopt spherical form.