512 Physiologie. 



C' G H l8 Az 4 ; eile peut deriver soit du biacetyle, soit de l'acetylmethyl- 

 carbinol. Or, le liquide distille ä partir duquel on a obtenu l'osazone 

 reduit la liqueur de Fehling ä froid, et agit sur la lumiere polarisee. 

 Le biacetyle ne possede pas ces deux proprietes; on a donc affaire ä 

 l'acetylmethylcarbinol CH 3 — CO — CHOH — CH 3 . 



Le B. subtilis et le Tyrothrix tenuis donnent egalement de l'aceryl- 

 methylcarbinol. Jean Friedel. 



Fernbach, A., Quelques observations sur la compo- 



sition de l'amidon de pommes de terre. (C. R. de 



l'Acad. des Sciences de Paris. T. CXXXVIII. 15 Fevr. 1904.) 



La fecule de pommes de terre renferme toujours du phos- 



phore, dont la proportion, evaluee en acide phosphorique, peut 



depasser 2 g. par Kilogramme de matiere seche, Ce phos- 



phore ne provient pas de matieres minerales, mecaniquement 



entrainees par les granules d'amidon, au cours de la fabrication 



de la fecule ; il fait partie integrante du granule d'amidon. 



Les petits granules de fecule representent un noyau rela- 

 tivement riche en phosphore, sur lequel viennent se superposer 

 peu ä peu pour former des grains de plus en plus gros, des 

 couches d'amidon depourvues de cet element. Ce phosphore 

 ne semble pas appartenir, exclusivement tout au moins, ä de 

 la matiere organique azotee. jean Friedel. 



Matthaie, Gabrielle L. C, On the effect of Temperature 

 on carbon dioxide assimilation. (Proc. Roy. Soc. 

 1903. p. 355—357.) 



Determinations were made with leaves of cherry laurel 

 through a ränge of temperature from — 6° C. to 45° C. At 

 each temperature several different intensities of illumination were 

 employed. Neglect of this has led some investigators to 

 erroneous conclusions. There is thus obtained for each tem- 

 perature a maximal assimilation proper to that temperature. 

 The intensity of light required for specific maximal assimilation 

 varies directly with the magnitude of the maximum. When 

 this is once reached further increase in illumination or in 

 amount of CO2 supplied no longer produces any augmentation 

 of assimilation. 



When a leaf is exposed to light of high intensity the ab- 

 sorbed excess of radiation raises the temperature of the leaf 

 above that of the surrounding air — the excess sometimes 

 amounting to 10° C. The temperature of the leaf was therefore 

 determined by a fine thermoelectric junction in the substance 

 of the leaf. 



By keeping leaves under similar conditions before the 

 experiments the same condition as to nutrition was assured. 



In the course of the experiments it was clearly shown that 

 marked seasonal variations occur in the assimüatory power of 

 leaves from the same individual. 



