Physiologie. 503 



toplasm and hence lipon the percentage of water present. 

 Within certain limits as the temperature rises the viscosity de- 

 creases so affecting the velocity of Streaming. 



The energy expended in Streaming is only a very smalt 

 iraction of that produced by respiration. The force requirecl 

 increases enormously as the diameter of the passage in- 

 creases so that transference in mass of the highly viscous 

 ectoplasm through the interprotoplasmic conneetion becomes 

 practieally impossible except in the case of the relatively large 

 connecting Strands of seive-plates. De Bary's belief that the 

 protoplasmic processes in seive-piates are not connected is 

 disputed. It is suggested that only at death does such Sepa- 

 ration take place and that this is due to alteration in surface 

 tension. 



The energy for Streaming can be derived either from 

 aerobic or anaerobic respiration. Certain species of Cliara and 

 Nltella may exhibit slow Streaming for six or eight weeks 

 when kept in darkness in the absence of oxygen. Strong light 

 retards Streaming while weak light may indirectly accelerate it 

 in chlorophyllous cells. 



Acids, alkalis and metallic poisons retard Streaming; alco- 

 hols and anesthetics when dilute may accelerate it, but when 

 concentrated always retard it. 



As regards the action of electric currents it is found that weak 

 currents may accelerate Streaming while strong ones retard it; 

 the latent period of recovery decreasing as the temperature is 

 raised, up to a certain limit beyond which the latent period in- 

 creases. The effect produced by a weak constant current is 

 not influenced by its direction with respect to the plane of 

 Streaming. 



The only form of energy capable of producing Streaming 

 seems to be surface-tension-energy and this is probably brought 

 into play by the action of electric currents traversing the 

 moving layers, and maintained by chemical action in the sub- 

 stance of the protoplasm. E. Drabble (London). 



GAIDUKOW, N., Weitere Untersuchungen über den Ein- 

 fluss farbigen Lichtes auf die Färbung der 

 Oscillarien. (Ber. der D. Botan. Gesellsch. XXI. 1903. 

 p. 484.) 



Verf. zeigt, dass wie 0. sancta auch 0. caldariorum unter 

 dem Einfluss verschiedenfarbigen Lichtes sich im Sinne der 

 „complementären chromatischen Adaptation" ändert. Todte 

 Oscillarien oder Farbstoffextracte verändern ihre Farbe nicht in 

 diesem Sinne, die complementäre Farbenveränderung ist dem- 

 nach ein physiologischer Vorgang, welcher der Vermittlung 

 des lebendigen Zellplasmas bedarf. 



Eine Farbenadaptation gleicher Art findet Verf. auch in 

 der von früheren Autoren behandelten Farbenänderung der 

 Florideen. Küster. 



