CELL-CONTENTS AND CELL-WALLS. 31 



by the absence of chloroplasts. Carefully watch the 



rotation movement ; on the two sides of the colourless 



"indifferent line" the protoplasm moves in opposite 

 directions. 



31. Cyclosis in Staminal Hairs of Tradescantia. 



Take a newly opened flower, preferably on a warm day ; 

 cut off the stamens, mount in water, and examine the 

 hairs on the filaments each hair consisting of a row of 

 cells with violet sap. Note that the protoplasm in these 

 cells is in active movement in various directions ; that in 

 the thickest of the strands extending across the vacuole 

 two currents may be seen flowing simultaneously in oppo- 

 site directions ; and that in any part of the protoplasm 

 the movements may stop for a time and then start again 

 sometimes in the reverse direction. 



32. Influence of Temperature on Protoplasmic 

 Streaming. While watching movement in Elodea or 

 Nitella, place a piece of ice at the edge of the cover-glass, 

 and a strip of filter-paper at the opposite edge, so as to 

 draw cold water through ; the movement slows down and 

 stops, but starts again as the water gets warmed. Heat 

 the slide over a flame; with gentle warming the rate of 

 streaming is hastened, but if the slide is heated further 

 movement stops, and the protoplasm is of course killed if 

 the water is heated still further. 



A better method is to use a Ward's tube ( 19) and 

 draw through ( a ) air heated in a U - tube held over 

 a flame, (b) air chilled in a U-tube placed in chopped 

 ice. 



33. Effect of Chloroform. To observe the effect of 

 anaesthetics^ etc., use a Ward's tube cemented to a slide, 

 placing the specimen in a drop of water on a cover-glass, 

 inverting the cover, and sealing it air-tight over the 

 chamber. For experiments in which it is not desired to 

 lead gases through the apparatus, use either the Ward's 

 tube with the ends open or an ordinary moist-chamber 

 slide ( 18). 



