in
the immediate progeny, reappear in a subsequent generation; as where a
white child is born of two black parents, the grandfather having been a
white.[828]

The same author judiciously observes that, if different species mixed
their breed, and hybrid races were often propagated, the animal world
would soon present a scene of confusion; its tribes would be every where
blended together, and we should perhaps find more hybrid creatures than
genuine and uncorrupted races.[829]

_Hybrid plants._--_Kolreuter's experiments_.--The history of the
vegetable kingdom has been thought to afford more decisive evidence in
favour of the theory of the formation of new and permanent species from
hybrid stocks. The first accurate experiments in illustration of this
curious subject appear to have been made by Kolreuter, who obtained a
hybrid from two species of tobacco, _Nicotiana rustica_ and _N.
paniculata_, which differ greatly in the shape of their leaves, the
colour of the corolla, and the height of the stem. The stigma of a plant
of _N. rustica_ was impregnated with the pollen of a plant of _N.
paniculata_. The seed ripened, and produced a hybrid which was
intermediate between the two parents, and which, like all the hybrids
which this botanist brought up, had imperfect stamens. He afterwards
impregnated this hybrid with the pollen of _N. paniculata_, and obtained
plants which much more resembled the last. This he continued through
several generations, until, by due perseverance, he actually changed the
_Nicotiana rustica_ into the _Nicotiana paniculata_.

The plan of impregnation adopted, was the cutting off of the anthers of
the plant intended for fructification before they had shed pollen, and
then laying on foreign pollen upon the stigma.

_Wiegmann's experiments._--The same experiment has since been repeated
with success by Wiegmann, who found that he could bring back the hybrids
to the exact likeness of either parent, by crossing them a sufficient
number of times.

The blending of the characters of the parent stocks, in many other of
Wiegmann's experiments, was complete; the colour and shape of the leaves
and flowers, and even the scent, being intermediate, as in the offspring
of the two species of verbascum. An intermarriage, also, between the
common onion and the leek (_Allium cepa_ and _A. porrum_) gave a mule
plant, which, in the character of its leaves and flowers, approached
most nearly to the garden onion, but h