Electrophoresis of the venom and haemolymph of the scorpionButhus Judaicus E. S.

Zusammenfassung Die elektrophoretische Analyse des Skorpiongiftes vonButhus judaicus E. S. ergab den Gehalt von mindestens 6 Proteinfraktionen. Drei dieser Fraktionen waren bei pH 8,6 von kathodischer Beweglichkeit und von offenbar höchster Toxizität. Davon völlig verschieden war das elektrophoretische Bild der Eiweisse in der Skorpionhämolymphe.     

Joseph H. M. Wedderburn and the structure theory of algebras

Archive for History of Exact Sciences -     

Cell death and phagocytosis in the neuroepithelium of the developing retina. A TEM and SEM study.

Phagocytosis by neuroepithelial cells independent of the presence of pseudopodes is observed as the main mechanism of elimination of physiologically degenerating cells during the early development of the retina in the chick embryo.     

Ovulation and the role of the ovarian surface epithelium.

Epon sections from all tissue layers of the rabbit ovary, including the often neglected surface or germinal epithelium, were studied to elucidate the mechanism of follicle rupture. Scanning electron microscopy showed cells covering preovulatory follicles increased clearly in size up to 8 hours after human chorionic gonadotropin (HCG) injection. These showed an increasing number of large, intracellular structures with prominent rounded contours. Transmission electron microscopy showed large, electron dense, lysosomelike bodies in some cells 4 hours after HCG. These membrane-surrounded structures increased in size up to 8 hours after HCG, then decreased markedly. These obviously corresponded to the bodies found by light microscopy and scanning electron microscopy. Histochemistry revealed many represent lysosomes. During the last 2 hours before rupture, the dense bodies of the surface epithelium considerably decrease, signs of material emptying into vacuoles is found, and sometimes there is open communication from vacuoles towards the unerlying tunica albuginea. An extracellular edema appeared under the epithelium with degenerated fibroblasts and disintegrated collagen; these changes gradually proceeded inwards. Blood capillaries close to the membrana granulosa gradually showed small pores and close to ovulation the endothelial cells had gaps up to 3 mcm in diameter. The preovulatory follicles grew rapidly and an augmenting edema occupied the whole ovary. In the last hours before ovulation the membrana granulosa gradually dissociated. Whatever the net effect of the prostaglandins, prostaglandin F2alpha appears to be essential for follicle rupture since intrafollicular injections of antiserum blocked ovulation. Prostaglandin E1 promotes vascular permeability and lysosommal enzymes released extracellularly may be coupled to collagen degration. The enzyme synthesis and lysosomal growth in the surface epithelium of preovulatory follicles may be due to the high local concentration of sex steroids.     

Membrane fractions of rabbit granulocytes. 1. The presence of ouabain-sensitive ATPase and the electrophoretic patterns.

In one or two membrane fractions isolated from the homogenate of casein-induced rabbit granulocytes ouabain-sensitive ATPase activity was found definitely. Electrophoretic patterns of these membrane fractions showed no significant differences in staining for carbohydrate and protein.     

A beautiful sea: P. A. M. Dirac's epistemology and ontology of the vacuum

This paper charts P.A.M. Dirac's development of his theory of the electron, and its radical picture of empty space as an almost-full plenum. Dirac's Quantum Electrodynamics famously accomplished more than the unification of special relativity and quantum mechanics. It also accounted for the ‘duplexity phenomena’ of spectral line splitting that we now attribute to electron spin. But the extra mathematical terms that allowed for spin were not alone, and this paper charts Dirac's struggle to ignore or account for them as a sea of strange, negative-energy, particles with positive ‘holes’. This work was not done in solitude, but rather in exchanges with Dirac's correspondence network. This social context for Dirac’s work contests his image as a lone genius, and documents a community wrestling with the ontological consequences of their work. Unification, consistency, causality, and community are common factors in explanations in the history of physics. This paper argues on the basis of materials in Dirac's archive that --- in addition --- mathematical beauty was an epistemological factor in the development of the electron and hole theory. In fact, if we believe that Dirac's beautiful mathematics captures something of the world, then there is both an epistemology and an ontology of mathematical beauty.     

Optimal Aminco-Bowman spectrophotofluorometer slit sizes and arrangements for the analysis of serotonin-O.P.T.

Résumé Une sélection des dimensions et des arrangements optimaux des fentes a été étudiée pour l'évaluation du complexe sérotonine-O.P.T. (o-phthaldialdéhyde) au moyen du spectrophotofluorimètre Aminco-Bowman. Les meilleures conditions ont été réalisées avec les dimensions de 5.0, 4.0, 5.0, 5.0, 4.0, 5.0 et 5.0 mm dans les positions 1–7 respectivement.     

Study of the metabolites ofPhyllosticta maydis. I. Isolation and partial identification

Summary Various metabolites of the fungusPhyllosticta maydis have been isolated, particularly mevalonolactone. The most interesting of these compounds, which is highly toxic to corn seeds (Zea mays), and which is probably a complex polyol, is the subject of the present report.Acknowledgment. The authors are indebted to Professor T. Gäumann for his cooperation and Dr J.C. Tabet who performed the measurements of mass-spectrometry.     

Instruments and rules: R. B. Woodward and the tools of twentieth-century organic chemistry

The paper illustrates how organic chemists dramatically altered their practices in the middle part of the twentieth century through the adoption of analytical instrumentation — such as ultraviolet and infrared absorption spectroscopy and nuclear magnetic resonance spectroscopy — through which the difficult process of structure determination for small molecules became routine. Changes in practice were manifested in two ways: in the use of these instruments in the development of ‘rule-based’ theories; and in an increased focus on synthesis, at the expense of chemical analysis. These rule-based theories took the form of generalizations relating structure to chemical and physical properties, as measured by instrumentation. This ‘Instrumental Revolution’ in organic chemistry was two-fold: encompassing an embrace of new tools that provided unprecedented access to structures, and a new way of thinking about molecules and their reactivity in terms of shape and structure. These practices suggest the possibility of a change in the ontological status of chemical structures, brought about by the regular use of instruments. The career of Robert Burns Woodward (1917–1979) provides the central historical examples for the paper. Woodward was an organic chemist at Harvard from 1937 until the time of his death. In 1965, he won the Nobel Prize in Chemistry.     

A study and critique of the teaching of the history of science and technology. Interim report by the committee on undergraduate education of the history of science society (U.S.A.)

A great deal is known about the technical issues surrounding the introduction of Hugo De Vries's mutation theory and the subsequent development of the modern genetical theory of natural selection. But so far little has been done to relate these events to the wider issues of the time. This article suggests that extra-scientific factors played a significant role, and substantiates this by comparing De Vries's respect for the original Darwinian spirit with Thomas Hunt Morgan's use of the mutation theory as part of an attack on the whole philosophy of Darwinism. In particular, it is argued that Morgan's attitude was dictated by his moral objections to the picture of a world dominated by struggle.