194 



plantlets as well, were placed in a 17 per cent, solution of cane sugar and 

 left for a few minutes. This was sufficient to bring about a plasmolysis 

 in all the cells and make the plasmodesmen evident when stained. This 

 is shown in Fig. 3. The fine strands of protoplasm ran from the proto- 

 plasts to pits in the wall and from there through the wall to the opposite 

 protoplasts. If the protoplasts were contracted too much by plasmolysis 

 they were broken and the fragments could often be seen (Fig. 3). 



When moss-cells were plasmolized in the way above mentioned they 

 were fixed in a 1 per cent, solution of chromic-acetic acid, then washed 

 in water and the walls swollen in the usual way. 



The walls must be swollen considerably in Funaria hygrometrica to 

 locate exactly the passage of the plasmodesmen. Although the proto- 

 plasmic fibers running from the contracted protoplasts were visible even 

 directly after plasmolyzing they were made much more evident by stain- 

 ing with clove oil or Hoffman's blue. 



The importance of plasmodesmen uniting the various protoplasts of 

 a plant is evident in several ways. Experiments have been made to show^ 

 that stimuli may be transmitted through them. Even certain nutrient sub- 

 stances^ may pass through them in mass or by diffusion, and Miehe^ has 

 even observed that nuclei may under certain conditions pass from one cell 

 to another by means of the pores of the plasmodesmen. 



'Townsend, Jahr. f. wigg. Bot. 1897, Bd. 30, p. 484. 

 "PfeflFer, Pflanzenphysiologie zweite Auf. Bd. II, p. 225. 

 ^Miehe.Flora, p. 115. 



