are those that assist in the
formation of fruit jellies. Some of these substances are liquid when
hot, and gelatinize on cooling; by too long boiling they lose this
property of gelatinizing; hence the precaution that is taken in the
making of fruit jellies not to boil the juice too long.

The subject of the ripening of fruits like the apple has been
extensively studied, as has also that of the subsequent decay. According
to recent researches, early varieties of apples contain little starch
when picked, and do not keep well. The season, soil, and age of the tree
affect the composition of the fruit. It has been shown that sugar is
sure to be formed from the starch in the process of ripening, after the
fruit is taken from the tree, and during the winter the cane sugar is
gradually, and finally almost entirely, changed to directly-reducing
sugar. The maximum sugar content is reached earlier the earlier in the
season the apple ripens. Late winter varieties reach this point as late
as November. There is much starch in the latter when picked, which
gradually changes to sugar on keeping. This process is analogous to the
ripening of the banana. This fruit is picked while green, and from it is
made by the natives of South America a flour which is a good farinaceous
food, and readily answers the place of the starchy grains. We are
familiar with the fact that as the fruit ripens it contains large
quantities of sugar, and is edible uncooked, which fact is usually not
true of starchy foods.

The subject of the decay of the apple has been discussed in a very
interesting way in the _Popular Science Monthly_ for May, 1893, by Byron
D. Halsted. Though chemical changes take place here, also, and the apple
is finally resolved mostly into carbonic-acid gas, water, and mineral
salts, yet these changes are brought about by the action of various
fungi which find a soil favorable to their growth in the apple pulp.

Though apples are considered digestible and wholesome, their
digestibility is much increased by cooking. This is especially true if
some of the starch is not converted to sugar, for, as noted above,
starch, to be readily assimilated in the system, should be cooked. There
is probably no fruit that is so uniformly wholesome and so deservedly
popular with all classes as the apple. The apple and pear were known in
England before the conquest, and, indeed, probably before the Saxon
invasion. They have been gradually "improved" from the