32 AGRICULTURE FOR BEGINNERS 



molasses (or it may be easier in case you use a narrow tube 

 to fill it before attaching the bladder). Put the tube into 

 a jar or bottle of water so placed that the level of the 

 molasses inside and the water outside will be the same. 

 Fasten the tube in this position, and observe it frequently 

 for three or four hours. At the end of the time you should 

 find that the molasses in the tube has risen above the level 

 of the liquid outside. It may even overflow at the top. If 

 you use the lamp chimney, the rise will not be so clearly 

 seen, since a greater volume is required to fill the space in 

 the chimney. This increase in the contents of the tube is 

 due to the entrance of water from the outside. The water 

 has passed through the thin bladder, or membrane, and has 

 come to occupy space in the tube. There is also a passage 

 the other way, but the molasses can pass through the bladder 

 membrane so slowly that the passage is scarcely noticeable. 

 There are no holes, or pores, in the membrane, but still 

 there is a free passage of liquids in both directions, although 

 the more heavily laden solution must move more slowly. 



A root hair acts in much the same way as the tube in 

 our experiment, with the exception that it is so made as to 

 allow certain substances to pass in only one direction, that 

 is, toward the inside. The outside of the root hair is bathed 

 in solutions rich in nourishment. The nourishment passes 

 from the outside to the inside through the delicate membrane 

 of the root hair. Thus does food enter the plant root. From 

 the root hairs, foods are carried to the inside of the root. 



From this you can see how important it is for a plant to 

 have fine loose soil for its root hairs ; also how necessary 

 is the water in the soil, since the food can be used only 

 when it is dissolved in water. 



