CHAPTER III. THE ROOT 



I. OSMOSIS AND THE ACTION OF THE CELL 



Material. — For experiments in osmosis provide fresh and boiled 

 slices of red beet, a fresh egg, a piece of ox bladder or some parchment 

 paper; glass tubing, thread, twine, elastic bands, salt and sugar solutions. 

 A common medicine dropper with the small end cut off will answer instead 

 of tubing for making an artificial cell ; or an eggshell maj^ be used, by 

 blowing out the contents through a puncture in the small end, and care- 

 fully chipping away a portion of the shell at the big end, leaving the lining 

 membrane intact. The different liquids can be put into the shell and the 

 exposed membrane placed in contact with the liquid 

 in the glass, by fitting over the latter a piece of card- 

 board with a hole in the center large enough for the 

 exposed surface to protrude sufficiently to touch the 

 water. 



55. Object of the experiments. — In or- 

 der to understand clearly the action of roots 

 in absorbing nutrients from the soil, it will 

 be necessary to learn something about the 

 movement of liquids through the cells, upon 

 which the physiological processes of the 

 plant depend. For this purpose make an 

 artificial cell by tying a piece of ox bladder 

 or parchment paper tightly over one end of 

 a small glass tube, as shown in Fig. 71. 



Experiment 39. How does absorption take 

 PLACE IN THE CELL ? — (a) Put some Salt water in 

 a wineglass, partly fill the tube of the artificial cell 

 with fresh water, and mark on the outside of both 

 vessels the height at which the contained liquid stands. Set the tube 

 in the glass of salt water and wait for results, having first tested care- 

 fully to make sure that there are no leaks in the membrane. After half 

 an hour, notice whether there is any increase of water in the glass, as 

 indicated by the mark. If so, where did it come from ? Is there any loss 



53 



Fig. 71.— Artificial 

 cell. 



