De la réaction mitotique de l'épiderme de la tétine de cobaye à la suite d'applications répétées de diverses substances

Summary (1) The majority of substances tested produced a weaker mitotic reaction of the epidermis of the guinea pig nipple after 3 applications (24 h intervals) of the same substance than after a single application.(2) This decrease in the ability of the epidermic cells to be divided has to be attributed, it seems, to a habit-forming processus and not to an exhaustion of the cells; indeed after two applications of geraniol, the application of a substance of different nature, Hormoestrol, produced in the nipple epidermis a mitotic flare up as intense as that obtained in the epidermis of a nipple not previously treated.(3) Aldehyde C₉ alone, among the substances tested, does not produce a decrease of epidermic mitoses after three applications but induces cellular alterations.     

La spécificité de la réaction de Feulgen pour la détection de l'acide thymonucléique

Summary A number of experiments all led to the conclusion that the Feulgen reaction is a valuable test for thein situ localization of thymonucleic acid: there is thus no serious reason to doubt that this acid is a constituent of chromatin and chromosomes.     

Importance des modifications de la glycémie dans la régulation de la vitesse d'absorption de solutions de glucose de différentes concentrations chez l'animal intact

Summary In intact guinea-pigs fed with glucose solutions of different concentrations, the main limiting factor of absorption is not the gastric emptying but the hyperglycaemia.     

Microméthode potentiométrique pour la détermination de la cholinestérase

Summary A simple very sensitive and usefull method is described for the potentiometric micro-determination of the cholinesterase of blood serum, globules and tissues, using an ordinary potentiometer and an antimonium electrode. This method makes it possible to determine the cholinesterase in solutions of acetylcholine down to 3 mg %.     

Microméthode potentiométrique pour la détermination de la cholinestérase

Sans résumé     

Pharmacodynamie de la circulation cérébrale

Sans résuméRelation présentée au XXI^e Congrès International des Sciences Physiologiques, Buenos Aires, 9–15 août 1959.     

Les effets de l'autotransplantation préportale de la thyroïde chez la Rate

Zusammenfassung 90 Tage nach einer in der Gegend der Pfortader erfolgten Autotransplantation der Schilddrüse bei weiblichen Albinoratten zeigt die histologische Untersuchung der Transplantate alle Zeichen einer gesteigerten Tätigkeit. Dem entgegengesetzt befinden sich Nebenniere, Leber und Hypophysis in dem als Folge der Schilddrüsenextirpation beschriebenen Zustand. Dieser scheinbare Widerspruch stützt die Annahme einer Inaktivierung des Schilddrüsenhormons durch die Leber.     

Essais de solubilisation et de détoxification de la Tyrothricine

Summary As Tyrothricin —Dubos's discovery of the antibiotic agent extracted from cultures ofB. brevis — does not give true aqueous solutions and retains, in the colloïdal state of the usually employed solutions, toxic properties for polymorphonuclear blood cells, we have attempted to effect the solubilization and detoxification of this compound. Treatment with formalin in given proportions results in making it water-soluble. The action of the formalin-treated compound on blood cells suspended in Ringer's solution seems to show a loss of toxicity. Subcutaneous and intramuscular injections in mice do not give visible general toxic effects, and the experiments incite to further investigations in this direction.     

Propriétés phytobiologiques de la sérotonine

Summary The serotonin (5-hydroxytryptamin) which shows a slight influence upon the growth of plant tissues, acts upon water uptake by regulating cellular permeability (latter is activated in the case of K⁺).     

Aspects biochimiques de la Régénération

Summary A survey of the biochemistry of regenerating animals has been made: after a critical discussion ofChild's metabolic gradients theory, the relative importance of respiration rate, carbohydrates, proteins and nucleic acids metabolism are stressed. The similarities between biochemical processes in the embryo and the regenerating organism are pointed out.

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Une grande partie de cet article est la reproduction d'un chapitre de notre livre « Embryologie chimique » (Masson, Paris, etDesoer, Liége); nous tenons à remercier les éditeurs de l'ouvrage qui ont bien voulu marquer leur accord. On y trouvera une bibliographie étendue sur les modifications chimiques dont l'organisme en régénération est le siège.     

Le Palais de la Découverte

Sans résumé     

Etude photophysique de la ptérobiline

Summary The first results of a photophysical study on pterobilin (biliverdin IX , a Lepidopter blue bile pigment) are presented. From the absorption and fluorescence spectra, it is deduced that the low yield of fluorescence indicates a desactivation of the excited singlet state occurring mainly by a non-radiative process. Analyses of the chemical compounds formed after irradiation of pterobilin in methanol show that it is rearranged into a series of new blue pigments among which phorcabilin and sarpedobilin (the two neobiliverdins IX isolated from Lepidopters) have been identified.

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Remerciements. Nous remercions le ProfesseurJ. Bergerard pour son intérêt. Ces recherches ont été réalisées dans le cadre de l'ATP CNRS No. 4699-10.     

Au sujet de la mesure des modifications de l'adrénalino-sécrétion

Summary A method is described that allows blood samples to be taken repeatedly from the suprarenal vein, without changing the circulation in the adrenal glands or eliciting reflexes which could interfere with the adrenalin secretion. The vasoconstrictor properties of the blood samples are tested on an isolated blood vessel preparation.     

La nature de la substance minérale de l'os

Summary In answer to objections put forward byBrandenberger andSchintz against their theory concerning the chemical nature of bone salts, the authors afford supplementary evidence about the real crystalline and chemical entity of hydrated tricalcium phosphate. According to the conditions, the precipitate contains either dicalcium phosphate or lime and this affects the nature of the product obtained by calcination.The mineral bone substance is not a hydroxylapatite because it turns either to carbonato-apatite or oxyapatite according to carbon dioxide being kept or not in the crystal lattice. The X-ray patterns of those two apatites are undoubtedly different.

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Réponse à une note deE. Brandenberger etH. R. Schinz, Exper.4, 59 (1948).     

Quelques propriétés basiques de la streptomycine

Summary Streptomycin forms an insoluble complex with organic substances of which the isoelectric point is situated in the acid range such as cephalin, oleic, palmitic, and tannic acid.     

Activitéin vivo de dérivés de la thiourée contre le virus de l'influenza

Summary A large number of sulphur-containing compounds bearing the thiourea group -NH-CS-NH-, including substituted thiocarbanilides, 1-acyl-4-arylthiosemicar-bazides, 1-(arylaminothioformyl)-thiosemicarbazides, 4-aryl-1-(arylaminothioformyl)- thiosemicarbazides, and other related substances have been tested for potential antiviral activity. Several of these compounds have been found chemotherapeutically active against influenza virus.

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Communication présentée au Congrès international de Chimie pure et appliquée de Zürich (Juillet 1955).     

Interprétation chymique de la création et origine corpusculaire de la vie chez Athanasius Kircher

The famous Jesuit father Athanasius Kircher (1602–1680) tried to interpret the Creation of the world and to explain the origin of life in the last book of his geocosmic encyclopedia, Mundus subterraneus (Amsterdam, 1664–1665). His interpretation largely depended on the ‘concept of seeds’ which was derived from the tradition of Renaissance ‘chymical’ (chemical and alchemical) philosophy. The impact of Paracelsianism on his vision of the world is also undeniable. Through this undertaking, Kircher namely developed a corpuscular theory for the spontaneous generation of living beings. The present study examines this theory and its relationship with Kircher's chymical interpretation of the Creation in order to place it in its own intellectual and historical context and will uncover one of its most important sources.