164 LIFE OF A TREE. 
the most brilliant contrasts of the richest colours, 
golden and deep red. Disregarding other changes, 
the most remarkable alteration to which we are 
called to attend, is that which we all prize so 
much, the change from intense sourness to a 
delightful sweetness of taste. How is this ac- 
complished ? 
It has been found, that while the fruit is green 
it acts upon the air in the same manner as the 
leaves,—that is, it absorbs carbonic acid during 
the day, and exhales it at night. As it becomes 
more and more ripe, peculiar chemical changes 
take place in it, and the juice it contains gradu- 
ally becomes more and more charged with sugar, 
until at length it is full ripe, and it then loses 
its connection with the tree, and falls to the 
ground, 
After it 1s ripened, in a certain time it begins 
to rot. The oxygen of the air acts upon it, and 
reduces it to a soft pulpy mass; except the seeds 
which are contained within, and which seem to 
have been beautifully endowed with a peculiar 
power of resisting this change. In the common 
medlar, this rotting is commonly allowed to take 
place, and the fruit is not eaten until it has 
