That there are instances of decided decline in the quality of fruits is
certain. But on the causes of those changes pomologists do not agree.
One theory is, that fruits, like animals and vegetables of former ages,
may decline and finally become extinct. Should this theory be
established, the declension would be so gradual that a century would
make no perceptible change. But we do not credit the theory, even as
applied to former geological periods in the history of our globe. The
changes of past ages, as revealed in geology, have been brought about,
not gradually, but by great convulsions of nature, such as volcanoes, or
the deluge, that resulted in the destruction of the old order of things,
and in a new creation.
The true theory of this declension of varieties of fruits, is, that it
is the result of repeated budding upon unhealthy stocks, and of neglect
and improper cultivation. Apply the specific manures--that is, those
particularly demanded by a given fruit--prune properly, mulch well, and
bud or graft only on healthy seedling stocks of the same kind, and,
instead of declension, we may expect our best fruits to improve
constantly, in quality and quantity.