so again. On analogous grounds, I believe that the flowers in the above
specified anomalous cases which do not now intercross, either would do so
occasionally under different conditions, or that they formerly did so--the
means for affecting this being generally still retained--and will again
intercross at some future period, unless indeed they become extinct. On this
view alone, many points in the structure and action of the reproductive organs
in hermaphrodite plants and animals are intelligible,--for instance, the fact
of the male and female organs never being so completely enclosed as to render
access from without impossible. Hence we may conclude that the most important
of all the means for giving uniformity to the individuals of the same species,
namely, the capacity of occasionally intercrossing, is present, or has been
formerly present, with all organic beings, except, perhaps, some of the
lowest.

[ON CERTAIN CHARACTERS NOT BLENDING.

When two breeds are crossed their characters usually become intimately fused
together; but some characters refuse to blend, and are transmitted in an
unmodified state either from both parents or from one. When grey and white
mice are paired, the young are piebald, or pure white or grey, but not of an
intermediate tint; so it is when white and common collared turtle-doves are
paired. In breeding Game fowls, a great authority, Mr. J. Douglas, remarks, "I
may here state a strange fact: if you cross a black with a white game, you get
birds of both breeds of the clearest colour." Sir R. Heron crossed during many
years white, black, brown, and fawn-coloured Angora rabbits, and never once
got these colours mingled in the same animal, but often all four colours in
the same litter. (15/18. Extract of a letter from Sir R. Heron 1838 given me
by Mr. Yarrell. With respect to mice see 'Annal. des Sc. Nat.' tome 1 page
180; and I have heard of other similar cases. For turtle-doves Boitard and
Corbie 'Les Pigeons' etc. page 238. For the Game fowl 'The Poultry Book' 1866