MANUAL OF NATURE STUDY. 
65 
by these root-hairs and thus get into the structure 
of the plant. Dissolve a small quantity of table 
salt in a tumbler of water. Can root hairs now 
take up salt? Dissolve sugar. Can root-hairs now 
take up sugar when they drink the water contain¬ 
ing it? Could they have done so before it was 
dissolved? Can root-hairs take up grains of sand? 
See if sand will dissolve in water. Can root-hairs 
take up lime? See if lime is soluble in water. 
Then how do lime and sand or silicon get into the 
growth of the plant? We know these substances 
are there, for they form the strength to the stalk of 
wheat, grass, or corn, etc. It has been proved by 
experiment that when these substances are found 
in proper proportions they unite chemically, thus 
forming a substance that will dissolve in water. 
Thus united and thus dissolved in water the root- 
hairs have an easy task to perform in carrying 
these substances up to the factory. What, now, 
is the great use of water in plant life? I wonder if 
it serves the same purpose in animal life? 
Here the teacher should explain that the villi of 
the intestines are something like root-hairs dipping 
into the food which has passed from the stomach, 
and drinking the liquid which contains sugar, salt 
and other substances in solution. Can anything 
not dissolved be sucked up by these very minute 
