PERSONALITY OF PLANTS 
_ Certain plants manufacture lime and metal- 
lic oxides with which to harden the protective 
armour they wear. Many others generate nit- 
ric acid, carbonic acid and ammonia for use in 
their interior laboratories. Roots nearly always 
secrete a fluid which aids in the absorption of 
minerals from the earth. It is so powerful that 
quartz, flint and limestone are often scratched 
and corroded by its action. Above and below 
ground, plants are active chemical laboratories. 
The differences of taste, smell and colour 
which characterize leaves, blossoms and fruits 
are due to the presence of various organic com- 
pounds. These are largely volatile oils which 
are more complex than the substances involved 
in the simpler life processes. The slow or rapid 
evaporation of these oils influences the strength 
and character of an odour. When a flower or 
fruit passes through infinite gradations of 
colour, we can give no adequate account of the 
chemical changes involved. All we can do is 
to observe and to note. Sometimes infusions of 
iron sulphate or other chemicals in the soil 
darken the hues of flowers. Gardeners profit by 
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