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.     

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.     

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.     

Un nouveau type de détermination chromosomique du sexe chez les mammifèresEllobius lutescens Th. etMicrotus (Chilotus) oregoni Bachm. (Muridés-Microtinés)

Summary (1)Ellobius lutescens andMicrotus oregoni show the same type of sex-chromosomes. The diploid number is odd in both sexes, seventeen.(2) The odd element ofEllobius is morphologically alike in the male and in the female. InM. oregoni, the odd element of the male is acrocentric, that of the female metacentric.(3) Following a hypothesis ofWhite, it seems very probable that the heterochromosome of the male is built of the primitiveY (short arm) and the primitiveX (long arm) linked together. In the female of the same species (M. oregoni), the sex-chromosome represents both theX fused together.(4) Only the half of the Zygotes may develope, the other half being lethal.(5) The close kinship betweenEllobius andM. oregoni is certain, a parallel evolution appearing as highly improbable.     

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.     

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.     

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.     

Vernalisation deLinum austriacum L. par ablation des rameaux latéraux

Summary According to these experiments, it appears thatLinum austriacum L. needs vernalisation to bloom. The treatment at low temperature (vernalisation) may be replaced in the course of the first year by a process of mutilation, that is to say, the ablation of all lateral shoots as soon as they appear. The notion of the concentration of tropho-hormonal reserves in the aerial portion of the plant has been considered as a partial explanation of the phenomenon.     

Dégénérescence rétinienne expérimentale provoquée par le fluorure de sodium

Zusammenfassung Die Einspritzung von NaFl beim Kaninchen verursacht Netzhautveränderungen, welche derRetinitis pigmentosa ähnlich (Fundus, ERG, Histologie), aber auf einen Bezirk beschränkt sind.     

Comparaison de l'activité respiratoire d'Esch. coli pendant la bactériolyse due aux bactériophages de la série T1 à T7

Summary The course of bacteriolysis as determinated by the oxygen consumption of the bacteria is different during bacteriolysis produced by the phagesT _1,3,5,7 as compared with that produced by phagesT _2,4,6. With phagesT _1,3,5,7, the bacteriolysis occurs, rapidly, but incompletely after a latent period. With the phagesT _2,4,6 bacteriolysis occurs slowly and the course of the respiration shows a « plateau » but goes to completion. The biochemical mechanism of the bacteriolysis therefore seems to differ in both cases.     

Hypertension expérimentale et protéines sériques

Summary The authors investigated the distribution of serum proteins, especially the ₂ fraction, in rats with artificially induced hypertension (A), in similar rats made normotone by choline-free diet (B), and in a control group (C). A rise in the ₂ fraction of groupA andB was found, without a significant change of the other serum proteins.     

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⁺).     

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.     

Photolyse ultraviolette et photoréactivation des bactéries — Aspects de dépolymérisation et repolymérisation des acides nucléiques bactériens

Summary Electrophoretic analysis of bacterial substance proves the departure, from UV irradiated microbes screened from light for a certain time, of substances which were responsible for increasing the charge density by surface unit during the first moments which follow the irradiation by UV rays. Spectrophotometric analysis of liquids having contained these bacilli proves concommitantly the diffusion of those substances from the bacterial substance to the aqueous phase and reveals their nature. The photoreactivity which is possible during the first moments following the UV irradiation of bacilli, due to the presence of the fragments of depolymerisation of nucleic acid macromolecule in the bacterial substance, becomes impossible after the departure (diffusion) of those fragments to the aqueous phase. These observations seem to show that the phenomenon of photo-reactivity is connected with the repolymerisation of the macromolecule primitively divided of desoxyribonucleic acid.     

Actions de la néostigmine,du D.F.P. et du 3318 CT sur la sensibilité du rectus de grenouille aux esters acétique,propionique et butyrique de la choline

Summary The potentiating effects of Neostigmine, D.F.P. and 3318 CT (a selective true cholinesterase inhibitor) on acetylcholine (ACh), propionylcholine (PrCh), butyrylcholine (BuCh) and amyltrimethylammonium (AmT), have been studied using the frog's rectus abdominis. Neostigmine increases the actions of the three esters much more than that of AmT. Low concentrations of D.F.P. potentiate maximally BuCh but have practically no effect on ACh, PrCh, and AmT. 3318 CT potentiates AcCh and PrCh but inhibits BuCh and AmT.These results indicate the specificity of the hydrolysis of pharmacologically active doses of BuCh, on the one hand, of AcCh and PrCh, on the other hand, by different enzymes or the frog's rectus.Results obtained with high concentrations of D.F.P. and with association of the different anticholinesterases indicate that a maximal or nearly maximal potentiation of one of these esters is already obtained with the specific inhibitor concerned; the supplementary inhibition of the non-specific enzymes thus appears to have no or only a poor effect.     

L'action du 2,4-dichlorophénoxyacétate de sodium sur les végétaux

Zusammenfassung 0,5prozentige Lösungen von 2,4-dichlorophenoxyessigsaurem Natrium verhindern das Keimen vonAgrostemma Githago, Hordeum vulgare undTriticum vulgare. Das Wachstum junger Pflanzen der drei Arten wird durch Verpflanzen auf mit 0,5prozentigen Lösungen dieses Stoffes getränktem Sand gehemmt. Schwächere Lösungen gestatten das Wachstum, es ist aber verlangsamt und die Pflanzen tragen Mißbildungen verschiedener Art, die an die nach Einwirkung von Colchicin und Heteroauxin beschriebenen erinnern. Stark verdünnte Lösungen (5·10^–6) beschleunigen das Wachstum und regen die Wurzelbildung an; diese Wirkung ist beiHordeum vulgare besonders deutlich.