EXERCISE 4. TO SHOW HOW PLANTS TAKE UP FOOD 

 MATERIAL FROM THE SOIL 



Equipment: Small glass tube or funnel with a long 

 stem; a piece of bladder or parchment paper; some sugar 

 or molasses; a glass can, or wide-mouthed bottle. 



Method: Soak the bladder or 

 parchment in water until soft, stretch 

 the membrane over the end of the 

 funnel and hold it securely by wrap- 

 ping tightly with waxed thread. Now 

 fill the funnel with a strong sugar 

 solution or with molasses, until the 

 liquid stands about one inch in the 

 stem. Partly fill the jar with water 

 and insert the funnel until the water 

 on the outside is at the same level as 

 the molasses or sugar solution on the 

 inside of the funnel. In a short time 

 the solution in the funnel will be 

 seen to rise above the level of the 

 water in the jar and after a time 

 overflow at the top if the stem of the 

 funnel is not too long. 

 Discussion: This increase in the volume of molasses 

 or sugar solution is due to the entrance of water through 

 the bladder or parchment membrane. There is a slow 



8 



Fig. 4. — Arrangement 

 of a Bladder Mem- 

 brane to Show How 

 Plants Take up Food 

 Material. 



