1. Both Van Mons and Knight believed in a degeneracy of plants; but
the degeneracy of the one system is not to be confounded with that of
the other.
Knight believed that varieties had a regular period of existence;
although, as in animal life, care and skill might make essential
difference in the longevity, yet they could in nowise avert the final
catastrophe; a time would come, sooner or later, at which the
vegetable vitality would be expended, and the variety must perish by
exhaustion—by _running out_.
Van Mons believed that an improved variety tended to return to its
normal state—to its wild type; and although he did not believe that it
could ever be entirely restored to its wild state, it might go so far
as to make it worthless for useful purposes.
Knight believed in absolute decay; Van Mons, in retrocession.
According to Knight’s theory, varieties of fruit cease by the natural
statute of limitation; according to Van Mons, they only fall from
grace.
There can be no reasonable doubt that Van Mons held the truth, and as
little, that Knight’s speculations were fallacious. Bad cultivation
will cause anything to run out; no plant will perfect its tissues or
fruit without the soil affords it elementary materials. The so-called
exhausted varieties renew their youth when transplanted into soils
suitable for them.
2. Against Van Mons’ method it is urged, that it enfeebles the
constitution of plants; that, _enfeebling_ is the very key of the
process. This Mr. Downing urges with emphasis, saying that, “the
Belgian method (Van Mons’) gives us varieties often impaired in their
_health_ in their very origin.” It is one thing to restrain the energy
of a plant, and another to enfeeble it. It may be enfeebled until it
becomes unhealthy, but rampant vigor is as really an unhealthy state
as the other extreme. A tree refuses fruit and is liable to death from
a coarse, open, rank growth, as much as from a languor which
suppresses all growth.
No; that which we imagine Van Mons to have effected was a smaller, but
more _compact_ and _fine_ growth. Nor are we aware that, _as a matter
of experience_, the Belgian pears prove to be any more tender than the
English. Doubtless, there are trees of a delicate and tender habit in
the number, but as few, in proportion to the great number originated,
as by any other method.
The two main objections to the plan are the _time required_, and the
utter _uncertainty of the results_. To imitate the process would
require a Van Mons’ patience, in which, probably, he was never
surpassed, and his enthusiasm, which was extraordinary even for a
horticulturist, a race of beings supposed to be anything but
phlegmatic.
The _uncertainty_ is such as to prevent any determinate improvement.
We get, not what we may wish, but whatever may happen to come. Nothing
that art can do would affect the size, color, hardness, or in any
respect, the general character of the fruit.
It is in these aspects that Knight’s method must always be preferred
as a practical system. We can obtain a return for our labor in
_one-fifth_ the time; and, what is even more important, we can
regulate, before-hand, the results within certain limits. The new
fruit is to be made up of the qualities of its parents in various
proportions. We cannot determine what the proportions shall be, but we
can determine what parents shall be selected. Nor is it at all
improbable that, when knowledge has become more exact by a longer and
larger experience, the breeder of fruit may cross the varieties with
nearly the same certainty of result as does the breeder of stock. It
is upon this feature, the power which science has over the results to
be obtained, that we look with the greatest interest; and we urge upon
scientific cultivators the duty of perfecting our fruits by judicious
breeding.