42 Physiologie der Zellen, Gewebe und Organe. 



Das wichtigste Ergebnis vorliegender Untersuchung läßt sich wie folgt zu- 

 sammenfassen: Eine Reihe früherer Untersucher hatte in den Darmzellen ver- 

 schiedener Nematoden (ßclerostomimi , Ascaris u. a.) stark lichtbrechende Körn- 

 chen beobachtet, deren Natur aber nicht aufgeklärt. Verf. kommt zu dem Er- 

 gebnis, daß diese „Sphärokristalle" aus Gips bestehen und zwar auf Grund der 

 Tatsache, daß nach Lösung der Körnchen in konzentrierter Salpetersäure bei 

 Zusatz von Baryumchlorid der charakteristische Barytniederschlag entsteht und 

 die spektrale Untersuchung der „Sphärokristalle" die Spektrallinien des Calciums 

 (ebenso \wie die Flammenreaktion) anzeigt. v. Kemnitz (München). 



Hierzu: Nr. 83, 94—99, 127, 133. 141. 



Physiologie der Zellen, Gewebe und Organe. 



93) Keeble, F., Armstrong, E. F. and Jones, W. N., The Formation of 

 the Anthocyan Pigments of Plauts. Part IV. The Chromogens. In: 

 Proc. Royal. Soc. B., Bd. 86, S. 308—317, 1913. 



Previous papers of this series have dealt with the oxydases concerned in 

 anthocyan formation; the present paper deals with the occurrence and recognition 

 of the chromogens. A number of experiments are described, e. g. if coloured pe- 

 tals of Stocks (Ilatthlolu) are placed in alcohol, they rapidly lose their colour, 

 but if then placed in water, they quickly regain the identical colour which they 

 had before. Evidence is given that this is not an "indicator" reaction, like that 

 of the colour change of litmus, but is due first to the reduction of the anthocyan 

 to a colourless chromogen, and then to its re-oxidation by an oxydase. It is thus 

 concluded, as a result of the varied experiments described in the paper, that there 

 are present in the coloured portions of plants chromogen, a reducing agent of 

 unknown nature, and oxydase. The action of the oxydases is inhibited by alcohol, 

 and the coloured anthocyan is thus reduced to colourless chromogen by the re- 

 ducing agent; when alcohol is replaced by water, the oxydases, which have not 

 been destroyed, resume their activity and again couvert the colourless chromogen 

 to anthocyan pigment. Either several chromogens or several distinct oxydases 

 exist in different varieties, determining the colour which is produced. The factor 

 which determines in which direction the pigment-producing reaction shall go is 

 the amount of active water present. Increase of water increases the activity of 

 the oxydases, decrease of water, that of the reducing agent. 



Doncaster (Cambridge). 



93) Maze, P., liuot, M. et LeMoigue, M. (Paris, Institut Pasteur;, Chlorose calcaire 

 des plantes vertes. Röle des excrötions des racines dans l'absorption du 

 fer des sols calcaires. In: C. R. Acad. Sc. Paris, Bd. 157, Heft 12, S. 495— 498, 

 1913. 



Anterieurement, les auteurs ont demontre que la Chlorose, attribuee ä la richesse 



excessive du sol en calcaire, est due ä l'insolubilisation de fer par le carbonate de calcium. 



Dans la presente note les auteurs montrent que les plantes qui souflfrent du manque 



de fer ne sont pas en mesure d'en dissoudre les oxydes parce que les excretions des racines 



sont privees d'acides mineraux et organiques libres. 



L'azotate de fer, en pulverisation, demeure les traitement de choix de la Chlorose. 



C. L. Gatin (Paris). 



Hierzu: Nr. 73, 75, 80, 86, 87, 90, 100, 101. 



