Untersuchungen über die Bildung der Reblaus-Blattgalle

Résumé La transmission expérimentale de la salive du Phylloxéra peut stimuler les jeunes feuilles de la vigne se trouvant encore dans la phase de végétation à former des galles. A cet égard, l'endopolyploidisation du tissu foliaire qui est exposé à la stimulation de la formation gallicole prouve un événement fondamental de la cécidogenèse.     

Elektrophysiologische Untersuchungen über die Ultraviolettempfindlichkeit von Insektenaugen

Summary Using the electroretinogram, the relative spectral sensitivity of the compound eye of the cockroachPeriplaneta americana and the flyCalliphora erythrocephala has been measured between 347 and 673 m μ. Besides the well known sensitivity distribution for spectral lights between red and blue, a further rise of sensitivity is demonstrated in the violet and ultraviolet part of the spectrum, reaching the highest value at the shortest wavelength available. Using selective adaptation (P. am.) and different stimulus intensities (C. er.), sensitivities for ultraviolet light were shown to be independent from those in the remaining part of the spectrum. Thus, more than one photopigment are assumed to be present in these eyes, one of them responsible for vision in the ultraviolet.

---

---

Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Untersuchungen über Aktinpolymerisation

Summary The suggestion is put forward that the polymerisation and ATP-splitting in actin are independent processes and that perhaps fats and lipoids are concerned in ATP-actin binding. (A comparison is made between the strength of ATP-binding of different actins.)     

Untersuchungen über die Genetik der Aposporie bei pseudogamen Potentillen

Summary It may be supposed that the somatic and generative apospory of the genusPotentilla is due to different factors and that these factors have a quantitative effect.     

Untersuchungen über die Ursache der galvanotaktischen Reaktionen bei Fischen

Résumé Nous avons pu montrer, en bloquant le système nerveux périphérique par une méthode opératoire ou au moyen de substances pharmacologiques (spécialement du curare), que la réaction de position typique des poissons aux champs électriques est déclenchée par une excitation directe des muscles correspondants. La réaction la plus forte s'observe lorsque l'axe sagittal des animaux est perpendiculaire à la direction du champ. Chez des animaux narcotisés ou privés du système vestibulaire, de même que chez les Soles et quelques autres poissons, les lignes de force du champ devraient donc être verticales pour déclencher une réaction galvanotactique semblable. Nous savons en effet par l'anatomie et par la physiologie des mouvements qu'aucune réaction galvanotactique nepeut résulter de contractions du ventre et du dos. Le «Tetrodon», dont la nage n'est pas commandée par les groupes musculaires du tronc, ne manifeste aucune réaction galvanotactique.     

Weitere Untersuchungen über die Wirksamkeit von Oxytryptaminderivaten im Strahlenschutzversuch

Summary The radioprotective action of some further oxytryptamines is investigated and the structure-activity relationship discussed. Deseril which neutralizes the protective effect of oxytryptamines, does not impair the radioprotective properties of cysteamine, tyramine, histamine or noradrenaline.     

Vergleichende Untersuchungen über die Dekorporationseffektivität einiger neuerer Chelatbildner

Summary The influence of several new polyaminopolycarboxylic acids on the distribution of carrierfree radiocerium in the organs of the rat was studied. Some theoretical and practical implications of the experimental findings are discussed.     

Elektronenoptische Untersuchungen über die Entstehun g «stachliger» Streptomyces-Sporen

Summary It is demonstrated, by electron-optical photography in a Streptomyces strain of the morphological section spira, that the spines of the spores arise from the membrane of the aerial mycelium hyphae and can be decomposed by lysozyme.     

Vergleichende Untersuchungen über die hypertensive Wirkung von Aldosteron und Desoxycorticosteron

Summary In the adrenalectomized and unilaterally nephrectomized rat an investigation has been carried out on the influence of a four weeks' treatment with aldosterone and desoxycorticosterone-acetate in doses which are equieffective concerning sodium retaining capacity. Desoxycorticosterone-acetate produced hypertension, perivascular granuloma and renal lesions, whereas under the influence of aldosterone the blood pressure remained normal and no histopathological alterations could be found. Towards the end of the experiment the animals treated with desoxycorticosterone-acetate took up twice as much drinking fluid as the animals treated with aldosterone. Although the results obtained so far are only of a preliminary character it is obvious that aldosterone in doses which are equieffective concerning sodium retention does not produce the same side effects as desoxycorticosterone-acetate.     

Zur Diskussion über die Homogenität des Erdinnern

Summary According to considerations put forwards byW. Kuhn andA. Rittmann some years ago, it follows that the chemical composition of the interior of the earth must be rather homogeneous; the well-known discontinuity which occurs at 2900 km with respect to the propagation of longitudinal and transverse waves should not be due to a discontinuity of the material composition (not to an iron core). It is due to a continous decrease of the viscosity and thereby of the relaxation time; transverse waves of a period of e.g. 30 seconds will no more be propagated in a material whose relaxation time for tangential stress is below 30 seconds, while the longitudinal waves will suffer a decrease of the velocity at the same time.A criticism put forward byA. Eucken consists in the argument that a material in which the time of relaxation for tangential stress becomes equal to the period of the vibration will exhibit a considerable absorption coefficient for longitudinal waves too. It is now shown that the distance on which the period of vibration and the relaxation time are approximately equal is small compared with the wave length of the seismic waves in question, from which it follows that the resulting absorption of the longitudinal waves too will only be small.A further consideration shows that a mixture of 99 atomic % hydrogen and 1 atomic % of iron is most probably supercritical at a temperature of 5000° abs.A survey of the solubilities in question shows further that the hydrogen present in a mixture of 90% hydrogen and 10% iron should on the strength of the absorption coefficient be completely absorbed by the iron at 5000° abs. and at a total pressure of 2.10⁶ atmospheres.The main argument why the assumption of an iron core inside the earth must be dismissed remains the fact that the present state must be the result of an asymptotic processus which at least in its final phase has occurred under conditions similar to the present conditions of temperature, pressure and viscosity; these latter conditions are far from permitting the processus of sedimentation etc. which would be required.     

Neuere Anschauungen über die Meteorologie und Klimatologie des Föhns

Summary The results of new researches about the föhn in the Swiss Alps in connection with the theory ofH. von Ficker show that the energy of the cyclonic föhn has two sources: the pressure gradient and the baroclinic field. This is caused by the isobaric differences of temperature between the Alps and the free atmosphere in the lee. The result is a current with a descending component in the lee. At the beginning, the descent of the föhn is due to the outstreaming of the cold air on the ground. In its further development the energy of the föhn increases so much as to sweep the cold air off the valleys.The development of föhn in an anticyclonic system ist also explained. Furthermore the two kinds of föhn are discussed in regard to their climatological influences.

---

---

Physikalisch-Meteorologisches Observatorium Davos.     

Tierexperimentelle Studien über die Alkoholverbrennung

Summary While in dogs intravenously administered alcohol is eliminated as a straight function of time, it was found that the combustion of alcohol, when given intraperitoneally in rats, depends on the concentration at a given time. Since the dog — like man — belongs to a species with a slow alcohol combustion, while the rat (together with the mouse) has the highest metabolic velocity, it is supposed that the supply of alcohol dehydrogenase might determine not only the metabolic velocity as such but also the rhythm of alcohol combustion: when the ADH supply is low, the combustion capacity limit will be reached at low blood alcohol concentrations and the elimination curve will become linear.     

Regel über die nichtbesetzten Isotonenzahlen

Summary Of the neutronic numbers 1 to 126 nine are not represented by a stable isotope. The non existent neutronic numbers are those between the neutronic numbers of the two isotopes of an element with an odd atomic number.     

Quantitative Untersuchungen über den Nukleinsäureverlust des Gewebes bei Fixierung und Einbettung

Summary Quantitative chemical determination of nucleic acid shows that no loss of nucleic acid occurs on fixation with formalin andCarnoy's solution (24 or 2 h at room temperature) and after dehydration and embedding of the tissues. Small amounts of protein were shown in the fixative solution.

---

---

Ausgeführt mit Mitteln der Deutschen Forschungsgemeinschaft.     

Untersuchungen über Wachstumsfaktoren fürCandida Reukaufii

Résumé L'hétérotrophie deC. Reukaufii est confirmée. Cette espèce requiert dans des conditions données: la biotine, remplaçable par la désthiobiotine, l'aneurine, remplaçable par la pyrimidine. L'action au miel est étudiée.     

Über die Atmungsenzyme des Seeigeleies

Riassunto Le attività citocroma ossidasica, succino-deidrogenasica, DPNH e TPNH cit. c riduttasica sono state studiate in omogenati e frazioni mitocondriali e microsomiali di uova vergini e fecondate diParacentrotus lividus. I mitocondri contengono tutta l'attività citocromossidasica e succinodeidrogenasica, mentre i microsomi solo una metà della attività DPNH cit. c riduttasica totale. Spettri differenziali hanno rivelato la presenza, nei microsomi, di un citocromo avente una banda a 428–430 mµ.