Das Astronomentreffen im Jahre 1798 auf dem Seeberg bei Gotha

Ohne Zusammenfassung Vorgelegt von S. Ffügge     

Das Verhalten des Zitterwelses (Malapterurus electricus Gmelin) im homogenen Gleichstromfeld

Résumé On a observé que le malaptérure réagit à des excitations électriques externes (courant continu homogène) par une « galvanotaxie diphasique ». Ces résultats avec leurs détails mettent en évidence une différence bien nette entre le comportement du malaptérure et celui des autres poissons osseux non électriques.

---

---

Mit Unterstützung des « Conseil National de la Recherche Scientifique » (Beirut).     

Corpus luteum cells grown as monolayers

Zusammenfassung Die Fähigkeit der Corpus-luteum-Zellen als Monolayers zu wachsen wurde untersucht. Die von Schwein und Ratte entnommenen Gelbkörper wurden zerkleinert und mit einer 0,25% igen Trypsinlösung in eine Suspension übergeführt. Die Kulturen wurden bis zum 8. Tag beobachtet. Die wachsenden Luteinzellen zeigen die typische Form und auch die ausgeprägte Aktivität der ⁵-3-OH Steroiddehydrogenase.     

Corpus luteum function in ageing inbred mice

Summary Impaired breeding performance of aged female mice was associated with reduced numbers of ovulations and increased mortality of embryos. The amounts of progesterone in the sera, corpora lutea and uterine flushings of these animals were similar to those of young animals when measured by radioimmunoassay.Financial support was provided by the Medical Research Council (R.G.G.) and the Ford Foundation and one of us (R.E.F.) wishes to thank Lucy Cavendish College, Cambridge, for their support with a Calouste Gulbenkian Research Fellowship.     

Corpus cardiacum — a target for azadirachtin

Summary Azadirachtin A, an insect growth inhibitor derived from neem seed, when injected at a physiological dose, inhibits the hormonally controlled ovarian development inLocusta migratoria. Its tritiated dihydro derivative concentrates more in the corpus cardiacum than in the brain. Translocation and release of the neurosecretory proteins labeled with L-[³⁵S]-cysteine in the corpus cardiacum is very poor in locusts under azadirachtin stress. It is concluded that azadirachtin may influence the release of trophic hormones from the corpus cardiacum leading to alterations in timing and titer of morphogenetic hormone pools.     

Corpus luteum function in ageing inbred mice.

Impaired breeding performance of aged female mice was associated with reduced numbers of ovulations and increased mortality of embryos. The amounts of progesterone in the sera, corpora lutea and uterine flushings of these animals were similar to those of young animals when measured by radioimmunoassay.     

Das Ganzheitsproblem in der Biochemie

Ohne Zusammenfassung     

Das mittlere Molekulargewicht der Sternmaterie

Summary On account of the electrostatical forces between the ions and electrons in the interior of a star, the mean molecular weight µ should be given a higher value than is usually assumed. It is believed that a satisfactory theoretical calculation of has not yet been given, and that it does not seem to be possible. The determinations of the chemical composition of the stars are regarded as shaky, because they are based on the value of .     

Das Bild der heutigen Mathematik

Ohne ZusammenfassungAnsprache bei der feierlichen Rektoratsübergabe am 18. November 1954.     

Das Auftreten von Viruspartikeln inAbutilon-Chloroplasten

Summary The leaves ofAbutilon striatum v. Thompson infected with chlorosis proved to contain spheroid virus particles of about 800 Å diameter. Each particle consisted of a central dark staining core of about 160 Å. This central core is surrounded by an inner and an outer envelope. The particles are found in the cytoplasm, and there is evidence to show that virus particles are able to penetrate into the chloroplasts.     

Zur Mikroabsorptionsspektralanalyse im sichtbaren Spektralgebiet und im UV

Summary A new instrument for the U.V. spectrometry of microscopic preparations, which uses quartz objectives not only for magnification, but also for monochromatization, permits measurements up to extinctionsE of more than 2.

---

---

Mit Unterstützung der Ciba-Stiftung für chemische, mediziinsche und technische Forschung.     

Das Wachstum der Zellwand in synchronerChlorella

Summary By pulse labelling, it is shown that the relative growth rate of cell wall substances in synchronousChlorella has a sharp maximum at the time of autospore formation. The dependence on time of the rate of growth of the cell wall coincides with that of the rate of increase of the free space. Moreover, the increase of the nitrogen content of the cell wall also has a maximum roughly at the same time as the growth rate.     

Elektrocortin-Wirkung im Glykogentest

Summary Elektrocortin is 30 times as active as Desoxycorticosterone in raising the liver glycogen to the same degree.     

Das Elektroretinogramm der isolierten Katzennetzhaut bei Zuwachsreizen

Summary The electroretinogram of the isolated cat retina in response to incremental stimuli was studied with varying intensities of background and/or stimulus. The results are explained in terms of known components.     

Das beim Gefrieren von Gelen entstehende Eis

Summary Highly swollen gels which contain, in addition to a large amount of solvent, a spatial network formed by chains of a high polymer, show an abnormal lowering of the freezing point. This is caused by the fact that the network prevents the formation of macroscopically undisturbed crystals.If, in the course of freezing at this lower temperature, a conglomerate of microcrystals were created corresponding in size to the width of the network, one should be able to observe a broadening of the X-ray interference lines. Experiments have shown that no measurable broadening takes place.This is explained by the assumption that a crystal which is prevented from growing in the normal way by the surrounding filaments of the gel, when cooled to a suitably low temperature grows crystallites with a small cross-section corresponding to the mesh size. The crystallites thus formed are orientated in a crystallographically exact manner toward their supporting crystal and parallel to each other. Therefore, when reaching the necessary height, they unite to larger, ordered crystalline regions which incorporate the polymeric filaments. This explains the observed sharpness of the X-ray interferences as well as the observation that, upon heating of a frozen gel, the melting does not occur at the same low temperature as the freezing, but closer to the melting point of macroscopic ice.     

Das Zirkon-Alter granitischer Gesteine aus dem Gotthardmassiv

Ohne Zusammenfassung     

Das Spitzenwachstum der Fasern beiLinum perenne L

Summary In shoots ofLinum perenne apical growth was observed at both ends of the fibres. Their rounded tips, rich in protoplasm, protude into the middle lamellae of adjacent fibres or parenchyma cells. In addition to their apical growth, the fibre walls undergo symplastic growth with the walls of neighbouring cells. The formation of the pointed ends of fully developed fibres is described.