ALBERT

Notes: Résumé L'auteur critique l'idée que la polarographie démontra l'existence de complexes d'hématine ferreuse avec le peroxide, actifs dans la catalyse. D'autres expériences montrent que les dérivés de l'hématine et du peroxyde sont instables et provoquent la dégradation de la porphyrine. Les complexes de la catalase et du peroxyde ne sont pas actifs polarographiquement et contiennent probablement le fer à l'état ferrique. La théorie deWestheimer sur l'action de la catalase ne s'accorde pas avec les faits démontrant que les dérivés ferreux n'apparaîssent pas dans la réaction et que les complexes avec le peroxyde, autre que le premier composé, sont inactifs. On ne peut pas établir d'analogie bien fondée entre la catalase proprement dite et l'hématine libre.

Notes: Abstract Electron-microprobe analyses of the feldspars and associated ferromagnesian minerals in the peralkaline volcanics, comendites and pantellerites, are presented together with new data on the major and trace-elements of the rocks and residual glasses. The feldspar phenocrysts in the pantellerites span a narrower range (Or33–Or39) than those of the comendites (Or30–Or46); both sets show only limited increase in Or outwards, and the zoning is greatest in quartz-bearing assemblages. The feldspar microlites in the residual glasses are invariably more potassic (2–4% Or) than their associated phenocrysts. In pantellerites the feldspars become more potassic as the residual liquids become more sodic; thus the most potassic feldspar is found in the most sodic (and peralkaline) pantellerite. Of the ferromagnesian phenocrysts, aenigmatite is the most ubiquitous and is commonly associated with hedenbergite±fayalite, or ferrorichterite; in the later stages of crystallization (groundmass), it is associated with acmite, arfvedsonite and tuhualite. Aside from slight variation in Ti/Fe+Ti ratio, aenigmatite is virtually constant in composition. The pyroxenes from the different assemblages have zones which together almost span the range acmitehedenbergite. Both ferrorichterite and arfvedsonite incorporate F but not Cl, and are slightly potassic. Tuhualite exists as two varieties; one blue and potassic, the other violet and sodic; both varieties reject halogens. Using (estimated) free-energy data, a field in fo2, T space is postulated in which Fe-Ti oxides are absent; their place is taken by pyroxene and aenigmatite. The no-oxide field will be intercepted by a cooling liquid in which peralkalinity is increasing and in which fo2 is near but above the FMQ buffer. The characteristic pattern of trace-elements in peralkaline volcanics (e.g., high Nb, Ta, Zr, Mo, Zn, Cd, R.E, etc; low Sr, Ba, Mg) are considered to be as much evidence for the peralkaline (salic) condition as of the genetic process. Several lines of evidence suggest that at liquidus temperatures, peralkaline rhyolites are essentially anhydrous.

Notes: Summary The isolation and crystallization of an ester of myo-inositol and indole-3-acetic acid is described. The ester was extracted from mature corn (maize) kernels. On the basis of data for solubility in acetone, acetone-water mixtures and water, chromatographic data, and data on acyl migration the ester, as isolated, is tentatively identified as indole-3-acetyl-2-O-myo-inositol. The compound promoted growth in a flax callus culture and in the standard Avena coleoptile straight-growth test, the biological activity in the former tissue being relatively greater than in the latter.

Notes: General Résumé The investigations described herein were made primarily to obtain information for an adequate description of the hypothalamic neurosecretory system of the Zebra Finch, Taeniopygia castanotis, but further, to obtain some indication of the morphologic variations associated with functional changes. Comparisons have been made with a similar previous study of the White-crowned Sparrow, Zonotrichia leucophrys gambelii. 1. The neurosecretory system of the Zebra Finch differs from that of Zonotrichia leucophrys gambelii as follows: a) The median division of the supraoptic nucleus is relatively poorly developed and lacks the very large cells that are so characteristic of Z. l. gambelii. The most rostral part of the preoptic recess of the Zebra Finch is neither as thin-walled nor as strongly extended rostrally as in Z. l. gambelii. b) In the perikarya of the neurosecretory ganglionic cells of the Zebra Finch the neurosecretory material is predominantly in the form of droplets and globules in contrast to the predominance of fine granules in Z. l. gambelii. c) The median eminence has a somewhat different structure than that of Z. l. gambelii. In silver preparations the looping fibers, characteristic of the posterior division of the median eminence and especially of the infundibular stem in Z. l. gambelii, are less prominent; the fine neural structure is somewhat reticular, consisting of fine endings whose relationships to the supraoptico-hypophysial tract and tubero-hypophysial tract must be investigated more closely. The neuroglia of the median eminence of the Zebra Finch show cytologic indications of activity. Selectively stainable ependymal and glial loops are lacking. d) The neurosecretory tract, which passes in a rostro-caudal direction through the zona interna, is especially conspicuous. Its repletion with neurosecretory material is in contrast to the neurosecretory content of the zona externa. This suggests that the zona externa, with its palisade layer, has a functional role that is independent of that of the fibers leading to the neurohypophysis. e) The neurohypophysis of the Zebra Finch is much more variable than that of Z. l. gambelii; there are sac-like, diverticular, and compact types. 2. Among wild Zebra Finches there are extensive differences in amount of neurosecretory material. The density of neurosecretory material in the palisade layer of the median eminence appears to have an inverse relationship to gonadal development. 3. The neurosecretory system is well differentiated in nestlings. The neurosecretory ganglionic cells contain extensive amounts of neurosecretory material. There is also some neurosecretory material in the median eminence whereas the neurohypophysis contains the smallest amounts. 4. The neurosecretory system of Zebra Finches in captivity with water ad libitum is relatively rich in neurosecretory material. In the neurosecretory cells the droplet form is most prevalent. When Zebra Finches are subjected to restricted water intake by permitting 1. a single two-minute drink per day (approximately 5 ml intake per week) or 2. a single two-minute drink per week (0.5–1.0 ml intake per week) the neurosecretory system becomes more active with enlargement of the neurosecretory cells, their nuclei, and their nucleoli. In the first group the occurrence of neurosecretory droplets increases significantly. Large neurosecretory globules become common. In the second group fine granular neurosecretory material and paranuclear cap-like accumulations of granules appear. Herring bodies develop frequently in the infundibular stem and neural lobe. Water restriction does not appear to affect the amount of neurosecretory material in the palisade layer of the median eminence. When Zebra Finches are given solution of NaCl up to 0.5 M in concentration as the sole source of drinking fluid, there is a moderate activation of the system characterized by the appearance of fine granular neurosecretory material. Birds that are able to tolerate 0.7 or 0.8 M NaCl have extremely enlarged neurosecretory cells with conspicuous fine granular neurosecretory material although homogeneous globules of neurosecretory material continue to be present. Herring bodies appear. The neurohypophyses are not completely depleted. 5. Many Zebra Finches maintain normal body weight with 0.6 M NaCl as the only drinking fluid. With 0.5 M the daily volume intake is of the order of 1 to 2.5 times body weight. Some individuals survive in apparently good health with 0.7–0.8 M although fluid intake is drastically reduced and body weight decreases somewhat. NaCl intake as high as 70 mg per gram body weight per day may occur in birds drinking hypertonic NaCl solutions. The ability of the Zebra Finch to tolerate high concentrations of NaCl in drinking water exceeds that of other passerine species studied thus far. Similarly the ability to survive in cages in a dry, hot environment with a water intake of ca. 1 ml per week is remarkable for a small bird. 6. Increasing the duration of the daily photoperiod from 9 to 18 hours neither depletes the neurosecretory content of the median eminence nor causes gonadal development. This is consistent with field studies that indicate that the reproductive activities of this species are not timed photoperiodically.

Notes: Summary Administration of oestradiol-17β to Xenopus laevis Daudin results in profound modifications of hepatic ultrastructure. In all liver cells there is a considerable proliferation of the granular endoplasmic reticulum and an increase in the electron density of the nucleolus. The amount of stored glycogen is depressed. Injection of pregnant mare serum gonadotrophin causes a similar response in intact females but not in males or ovariectomized females, suggesting an indirect effect of this hormone by stimulation of ovarian oestrogen secretion. Oestradiol benzoate, oestrone and oestriol are also able to effect the described response, though in the last case the changes are less complete. Testosterone propionate, progesterone, and cortisone acetate are inert in this respect.