Physiologie. 603 



doses of zinc salts upon the growth of Sterigmatocystis illustrate this 

 point of view. 



Acceleration of vital processes by temperature. Van 't Hoff 

 made the generalisation that most chemical reactions are accelerated 

 by temperature to the extent that their rate is about doubled or 

 trebled for every rise of 10° C. 



This generalisation is shown to hold for the best known consti- 

 tuent processes of vital metabolism as respiration and assimilation; 

 and also for the growth rate and frequency of division of the colour- 

 less flagellate Chilomonas worked at by Maltaux and Massart. 



Conclusion: In conclusion it is pointed out that all serious 

 quantitative study of metabolic processes must be based upon the 

 conception of 'reaction velocity' and the Variation of this velocity 

 produced by the action of temperature, catalysts and the mass of 

 the reacting substances. 



Working on this basis we no longer need the vague unquan- 

 titative terminology of Stimulation for the most fundamental of the 

 observed 'responses' to external conditions. Three sets of phenomena 

 we have observed which, though usually treated in the category of 

 Stimulation, draw a clearer Interpretation from the conception of 

 reaction-velocity. These were: 1. the relation of development to the 

 absence or deficit of Single essential food constituents; 2. the occa- 

 sional striking effect of minute traces of added foreign substances 

 upon the whole rate of growth and metabolism; and 3. the general 

 doubling of the activity of vital processes by a rise of 10° C. 



J. J. Blackman. 



Bosscha, J., Observations sur l'influence de la lumiere 

 et de la chaleur sur la production de matiereorgani- 

 que par le theier. (Ann. Jard. Botan Buitenzorg. XXIII. I. p. 

 66-68. 1909.) 



Les variations de la clarte du ciel sont suivies en mesurant les 

 differences de temperature. Par un ciel tres clair la temperature 

 minimum sera basse, pendant que la temperature maximum sera 

 tres elevee. Au contraire pendant un jour morne la difference entre 

 les temperatures minimum et maximum, nommee par l'auteur „am- 

 plitude" sera faible. Chaque Variation d'amplitude correspond ä une 

 Variation de production dans le meme sens, jusqu'ä ce que la saison 

 pluvieuse ait cesse. A Taloen, une moyenne comprise 'entre 6 et 

 7 m.M. par jour est la limite oü le manque de pluie commence ä 

 influencer la production. Th. Weevers. 



Boupquelot, E. , Ueber das Vorhandensein eines blau- 

 säurehältigen Glukosids in Linaria striata DC. (Pharmaz. 

 Post. XLIII. 9. p. 81. 1910.) 



Die Schafe rühren die Pflanze nicht an. Der Verf. vermutete 

 als Ursache irgendwie Gift; in den Ardennen sammelte er blü- 

 hende Pflanzen zur Untersuchung. Sie wurden mit kochendem Al- 

 kohol behandelt. Es zeigte sich, dass die Art eine oder mehrere 

 durch Emulsin hydrolisierbare Glukoside enthalt. Der Blausäurege- 

 ruch machte sich schon bei der Untersuchung der mit Emulsin 

 versetzten Flüssigkeit bemerkbar. Auf 1 kg. frisches Kraut kamen 

 0-1478 auf HCN. Fast das gleiche Verhältnis fanden Verf. und 

 Danjon bei Sambncus nigra. Das blausäurehältige Glukosid liefert 

 unter Einwirkung von Emulsin: Blausäure, Benzoesäurealdehyd und 



