108 Physiologie. 



et l'intensite sont en relation etroite avec la quantite de diastase 

 qui a servi ä amorcer le phenomene. j e an Friedel. 



Gamble, F. W. and F. Keeble, The Bionomics of Convoluta 

 Roscoffensis, with Special Reference to its Green 

 Cells. (Proc. Royal Soc. London. Vol. LXXII. No. 47S. 

 July 1903.) 



The authors conclude, in Opposition to Geddes, Von 

 Graff and Haberlandt, that Convoluta has not lost its power 

 Oi independant nutrition, but that, on the contrary, it ingests 

 voraciously and indeed that the animal obtains little, if any, 

 iood from the reserves of its green cells, for if the animals be 

 kept alive in darkness the starch of the green cells disappears 

 with extreme slowness. The animals, however, do digest masses 

 of their own green cells. 



Direct proof that the green or yeliow cells of Protozoa, 

 Coelenterates, Turbellaria, and other animals are due to in- 

 fection from without has been obtained by Brandt for sea- 

 anemonies, and by Beijerinck and Famintzin for Hydra- 

 viridis and Stentor and in the latter cases the alga has been 

 identified as Chlorella vulgaris. In the case of Convoluta, 

 direct proof of infection is lacking, but the evidence points 

 very strongly to infection by colourless cells ingested with other 

 organisms from the egg capsules. These cells are taken up by 

 phagocytes and carried by them to their final Station in the 

 periphery of the body, and in this position the majority become 

 green. The green cells certainly obtain food from the animal, but 

 probably the animal derives little, if any, food from the green 

 cells. 



Convoluta is positively phototropic only under certain con- 



ditions. A sudden elevation of light-intensity induces negative 



phototropism. At the time of hatching, the animal is aphoto- 



tropic, but quickly becomes actively phototropic. The rays active 



n producing phototropism are the green. 



The blue rays which are active in inducing movement in 

 zoospores and in plants generally are without effect on Con- 

 voluta. E."Drabble (London). 



LAURENT, E., Sur l'existence d'un principe toxique 

 pour le Poirier dans les baies, les graines et 'es 

 plant ules du Gui. (Recherches de Biologie experimentale 

 appliquee ä I'agriculture. Tome I. 1901 — 1903. p. 282 



—283.) 



Das Keimen der Mistelsamen auf den Zweigen gewisser Birnen- 

 Sorten bringt die betreuenden Zweige mitten im Sommer zum Absterben. 

 Das Gewebe der Rinde stirbt an jenen Stellen ab und in den Gefässen 

 bilden sich Gummimassen, in Folge dessen die Wasserleitung verhindert 

 wird und die jungen Zweige während der heissen Zeit des Sommers 

 vertrocknen. Der junge Mistelkeimling geht dabei selber zu Grunde. 

 Die betreifenden Birnsorten sind also gegen die Mistel immun. Verf 



