La question des hétérochromosomes chez les Sauropsidés. I. Reptiles

Summary In contradiction to some Japanese authors (Oguma, Makino, Nakamura), we are unable to find any difference in the chromosome sets of the male and female ofLacerta vivipara (2N = 36). In a saurian, where the analysis is very easy (Chamaeleon bitaeniatus), there are, without the smallest doubt, 24 chromosomes in both sexes (20M + 4m). The evidence of a female heterogamety in turtles is by no means satisfying.     

L'activité succino-déhydrogénasique dans le tissu oculaire (étude histo-chimique)

Summary The author has studied, with different tetrazolium techniques (NT, INT, nitro-BT), the succinate dehydrogenase activity in the ocular tissue (cornea, ciliary body, lens, retina).     

Effets de la réserpine sur le développement d'Oedipoda coerulescens L. (Acridien,Orthoptère)

Summary Inhibitory effects of reserpine on ecdysis and chromatic adaptation inOedipoda appear to be linked with changes observed in both neural and neuro-endocrine regulating systems.     

La question des hétérochromosomes chez les Sauropsidés. Oiseaux

Summary The chromosomes of the fowl were studied with the aid ofMakino's andNishimura's water pretreatment squash technique, modified byMatthey, in embryonic spleen and gonads of both sexes. The number of chromosomes was found to be about 78; the numerical variations are to be ascribed to technical difficulties, caused by the extremely small size of the microchromosomes, rather than to an unchromosomelike behaviour of the latter, as was supposed byNewcomer andBrant. As to the exact number of chromosomes, we consider its determination beyond the possibilities of cytology. The 5^th largest pair of the male, represented by a single element in the female, could be identified as the sex chromosome pair, in accordance with the findings ofYamashina. The digamety might be of theZ-O orZ-W type.     

Paléotempératures indiquées par l'analyse isotopique de fossiles du crétacé inférieur des Hautes-Alpes (France)

Summary Paleotemperature determinations were made by the oxygen isotope method on 20 Belemnoids, 5 Aptychi and a Nautilus beak from the Lower Cretaceous of the Dévoluy area of the Hautes-Alpes (France). The data derived show a well-defined trend from higher temperatures in the Berriasian to a climatic minimum in the Barremian followed by a rise to the Albian maximum, previously observed elsewhere in Europe. The Aptychi are shown to be useful paleotemperature indicators utilizable in conjunction with Belemnoids. A Sequanian Aptychus gave a high temperature reading, indicating that the climate steadily cooled from Upper Jurassic times into the Barremian. The single Nautilus beak gave a result suggesting that this group of fossils may also prove valuable in similar studies in the future. The paleotemperature data also showed (by the stratigraphic position of the relevant Belemnoids) that the Aptian is either very attenuated or absent in the Dévoluy.     

Propriétés antiacétylcholinestérasiques du diiodométhylate debis-(diméthylamino-3-phénoxy)-1-3 propane,de ses dérivés phénoliques et des esters carbamiques correspondants

Summary Thein vitro anti-acetylcholinesterase properties ofbis-(dimethylamino-3-phenoxy)-1-3 propane dimethiodide (2842 CT) of two phenolics derivatives (3443 CT and 3116 CT) and of the two corresponding carbamic esters (3152 CT et 3113 CT) have been compared using human red blood corpuscles as enzyme source; under specified conditions, the Cl-50 are respectively 8 × 10^–7 M for 2842 CT, 3.5 × 10^–9 for the two phenolic compounds, and 1.5 × 10^–9 for the carbamic esters. The potencies of these phenols are very close to those of the carbamates, being a bit higher or lower depending on the concentration of the inhibitor and on the time of the readingThe two phenolic compounds, like 2842 CT, react readily with the enzyme contrarily to the carbamic esters which combine slowly. On the other hand the inhibition by the phenolic derivatives is as stable against washing as that by the carbamates. The carbamates, but not the phenols, show the slow displacement phenomenon.Some of these characteristics are compatible with the hypothesis that carbamic compounds could act through liberated phenolic functions but others indicate that carbamic groups have a role of their own.     

Etude du métabolisme de mescalines fluorées par Pieris brassicae (Insecte,Lépidoptère)

Summary The action of -fluorinated mescalins on induction of diapause in the cabbage butterfly. Pieris brassicae, has been studied. The introduction of fluorine into mescalin has no influence on this activity. This result suggests solvolysis of fluorine and in vivo formation of a common ethylimine intermediate. Activity decreases, however, with substitution of the nitrogen.     

Un cas nouveau de polymorphisme chromosomique intraspécifique chez un Mammifère (Leggada minutoides Smith. Rodentia-Muridae)

Summary The African mouse,Leggada minutoides Smith, shows a chromosomal polymorphism: a first male (Coast of Ivory) had 32 chromosomes; theX is a big metacentric, theY a big submetacentric and the autosomes are acrocentric, with the single exception of the biggest pair which associates two submetacentric elements. By a second male (Congo), 33 chromosomes are found, amongst them only one big submetacentric autosome. This statement and the odd diploid number shows clearly that we have to deal with an heterozygot, two acrocentric elements representing respectively one arm of the submetacentric autosome. Now, we may be sure that this male belongs to a population built of individuals having 32, 33 and 34 chromosomes. The origin of such a population must have arisen in a primitive population where 34 was the diploid number, through a centric fusion.Such cases pose the question of the balanced chromosomial polymorphism and of the adaptative value of each formula⁶.     

The early years of the Lycée and the Lycée des Arts. A chapter in the lives of A. L. Lavoisier and A. F. de Fourcroy

The first professors at the newly-established London University (later University College London) were appointed in 1827, but a chair in geology was not created there until 1841. In the intervening years, teaching in geology and palaeontology was included in other natural science courses. Early in 1831, John Phillips, keeper of the Yorkshire Museum at York, was prompted to give a formal course of geological lectures and subsequently he was informally offered the professorship, which he declined.     

Activité de la glycéraldéhyde-3-phosphate déshydrogénase dans la rétine du lapin et dans la rétinite pigmentaire expérimentale provoquée par le monoiodacétate. Etude histo-chimique

Summary The author established that, at the moment of the extinction of the electroretinographic response after i.v. injection of iodacetate, the glyceraldehydephosphate dehydrogenase activity is suppressed in the retina of the rabbit.     

Sur la caractérisation de dérivés guanidiques d'origine biologique par électrophorèse et chromatographie sur papier (chromatoélectrophorèse)

Summary Paper chromatography has been used in conjonction with electrophoresis in a perpendicular direction (chromatoelectrophoresis), in order to characterize various guanidoderivatives of biological interest and also citrulline. The isolation of definite spots can be obtained with a satisfactory selectivity by this procedure, at a higher speed than by bidimensional chromatography; and the use of a few coloured reactions (ninhydrine,Sakaguchi, diacetyle--naphtol andp-dimethylaminobenzaldehyde) on the same electrochromatogram has been successfully practised in this field.     

Cytologie comparée des Muridae. L'origine des Ellobii

Summary (1) The present paper deals with the chromosomial cytology of 11 species and underspecies ofMuridae. (2) The diploïd number being the same (2N=42), there are striking differences between two species ofBandicota, B. indica showing about 20 big metacentric chromosomes which are lackingB. bengalensis. (3)Meriones blackleri is characterized by 72 chromosomes, the species previously described possessing either 44 or 60 elements. (4) The study ofPhenacomys ungava confirms the view that 56 (54) is the primitive number in theMicroti. There is an interesting parallelism between the morphological and the cytological data. (5) A missing link betweenMicroti andEllobii has been found inMicrotus oregoni which possesses 17 chromosomes, its digamety belonging to the typeX-O, X-X. (6) Owing to the fact thatM. oregoni is more fossorial than the otherMicrotus, it is a morphological intermediate betweenMicroti andEllobii. (7) The genusChilotus (Baird) is also fully valid.     

Action duCorynebacterium parvum sur les taux de lysozyme (muramidase) sérique

Summary An i.v. injection of 548 g of killedCorynebacterium parvum into C57B1 mice leads to significant changes in serum lysozyme (muramidase) levels. After an initial fall at 24 h, the activity of the enzyme increased progressively, reached a peak on the 9th day and returned to control range after the 15th day.     

Georg Agricola (1494–1555) Zum 400. Gedenktag seines Todes am 21. November 1955

Ohne Zusammenfassung     

Sur le dédoublement par entraînement. La notion de sursaturation «rémanente»

Zusammenfassung Durch abwechselnde Übersättigungen und darauffolgende Kristallisationen bei variierender Temperatur konnten gewisse Razemate in ihre optischen Antipoden gespalten werden. Im Falle des Chloramphenicols ist das gesetzmässige Gelingen der genannten Prozeduren sehr bemerkenswert. Diese sogenannte «méthode de dédoublement par entraînement» wird begründet durch den Begriff derremanenten Übersättigung. Da diese im umgekehrten Verhältnis zur Menge jedes eingesetzten Enantiomeren variiert, kristallisiert das überschüssige Enantiomere, wogegen das andere, selbst bei Anwesenheit der eigenen Impfkristalle, in der Übersättigung bleibt. Die beschriebenen Erscheinungen sind durch Löslichkeitskurven darstellbar.     

Quelques problèmes physiologiques posés par leSalmo Salar. Intérêt de l'étude de lasmoltification type de préparation au comportement migratoire

Summary The author considers some physiological problems raised by particularities of the physiological cycle ofSalmo salar L. about which he and his fellow-workers have produced new data (especially those brought out by the physiological, normal fasting so particular to the adultS: The synchonic fasting of Mislin).He insists on the importance, for studies on the physiological mechanism of migrations and from the methodological point of view, of the following feature of the young Salmon in fresh water: a transformation which, in the population studied (S. s. of Adour waters), is so characteristic of and tightly bound to the preparation to catadromic migration that it marks the subjects ready for migration and makes it possible to particularise the new physiological conditions accompanying the phenomenon of migratory instinct (activation of thyroid and interrenal function, of some pituitary neurosecretions and secretions, metabolic changes ). By studying simultaneously: smoltified but not yet migrant fishes, smolts during migration, and a salmonid fish subjected to a current in conditions simulating those of migrating smolts, it is now possible to begin to distinguish the physiological features bound to the preparation for migration, from those resulting from migratory activity.     

Analyse expérimentale de l'expression de la mutation léthale récessive («ulcère») chez l'embryon dePleurodeles waltlii (Amphibien Urodèle)

Summary The autonomous expression of a recessive lethal mutation (ulcèreu), isolated in the salamanderPleurodeles waltlii Michah. is demonstrated by the way of parabiotic and telobiotic associations, allogenic chimaeras, heterotopic grafts of organ primordia and of anterior or posterior parts from lethal embryos.     

Essais d'élaboration des voies d'approche à la chimiothérapie du cancer. Action sur l'eau d'hydratation des tissus néoplasiques; action sur les protéines

Summary The recent successes in chemotherapy suggest that a solution of the same order should now be possible for cancer. The cause of cancer being still unknown, the therapeutic action aimed at is the creation in the organism of conditions unfavorable for cell multiplication. Certain of the factors essential for cell growth, such as the hydrocarbons, have already been studied in this light. The author has demonstrated the possibility of influencing the high degree of hydration of tumor tissue by the use of substances capable of effecting a homogeneous distribution of the dispersed substances in the aqueous phase. Furthermore, it was proposed to influence the protein repair accompanying cell multiplication by means of substances having an affinity for proteins. This was done to effect a condensation of protein elements before they reach the tumor, thus producing a return to the normal concentration of the free protein fraction, and, at the same time, a decrease in the turn-over of these elements through the tumor. Electrophoretic measurements made with theTiselius apparatus have made it possible to follow protein affinity and to suggest the synthesis of compounds containing quinone and imine groups which may prove valuable in future investigations along these lines.     

Comportement nucléaire anormal dans la racine d'Ornithogalum umbellatum L.

Zusammenfassung BeiOrnithogalum umbellatum findet sich in einzelnen Wurzelspitzen eine allgemein auftretende anomale Zweiteilung des Ruhekerns. Sämtliche Zellen einer Zellenreihe vollziehen die Teilungen synchron. Die getrennten Kernhälften liegen beiderseits einer Ebene, welche die Zellreihe in ihrer Längsrichtung durchschneidet.