sects, disease, plant-food, and the stock in the case of
grafted vines, give every vine a distinct environment and hence a
distinct individuality of its own. Peculiarities in a vine appear and
disappear with the individual. A variety can be changed temporarily by
its environment, but remove the incidental forces and it snaps back
into its same old self.

Heredity is not quite complete in the grape, however; for, now and
then, sports or mutations appear which are permanent and, if
sufficiently different, become a strain of the parent variety or
possibly a new variety. There are several such sports of the Concord
under cultivation. The grape-grower can tell these sports from the
modifications brought about by environment only by propagation. If a
variation is transmitted unchanged through successive generations of
the grape, as occasionally happens, it may be looked on as a new form.
"Pedigreed" vines, then, should be subject to a test of several
generations in an experimental vineyard before the grape-grower pays
the price demanded for the supposed improvement.

[Illustration: PLATE IV.--A well-tilled vineyard of Concords.]

CHAPTER IV

STOCKS AND RESISTANT VINES

Phylloxera, a tiny root-louse, made its appearance in France in 1861
and began multiplying with a fury unparalleled in the insect world. By
1874, the pest had become so widespread in Europe that it threatened
the very existence of the great vineyard industry of that continent.
All attempts to bring the pest under control failed, although the
French government offered a reward of 300,000 francs for a
satisfactory remedy. Numerous methods of treating the soil to check
the ravages of the insect were tried, also, but none was efficacious.
Finally, it dawned on European vineyardists that phylloxera is not a
scourge in America, its habitat, and that European vineyards might be
saved by grafting Vinifera vines on the roots of immune American
grapes. At once the reconstruction of vineyards in Europe was begun by
grafting the grapes on phylloxera-resistant roots. Meanwhile,
consternation spread to California when it was discovered that
phylloxera was running riot in some of the vineyards of the Pacific
slope; however, with the knowledge derived from viticulturists in
Europe, they too began reconstructing vineyards on immune roots,
without the same success as the Europeans, it is true, but with such
measure of success that it soon became the approved method