that white, yellow, or
striped roses are diseased when the color of the type species is red.
Nobody thinks of saying that double flowers are evidences of disease in
the plant, or that diminution in the size of leaves or variation in
their form is a disease. Why then should it be said that because leaves
may become of some other color than green, or become party-colored,
therefore they are diseased? If it be said that flowers are not leaves,
and that therefore the analogy is not a good one, the reply is, that
flowers in all their parts, and fruits also, are only leaves differently
developed from the type. This fact is a proven one, and so admitted to
be by all botanists and vegetable physiologists of the present day. If
it be objected that by becoming double, flowers lose the power of
reproducing the variety or species, the answer is, that this loss of
power is not necessarily the result of disease, but may arise from
various other causes. Because an animal is castrated, it surely will not
be claimed that therefore it is diseased. In man and in the higher
animals the power of reproduction ceases at certain ages, but it cannot
therefore be said that such men or animals are diseased. Neither is a
redundancy of parts an unequivocal evidence of disease.

Topknot fowls and ducks are as healthy as those which do not have such
appendages, and a Shetland pony is as healthy as a Percheron horse,
notwithstanding the difference in their size and weight. Again, color in
block or in variegation is not positive evidence of disease in animal
life. The white Caucasian is as healthy as the negro, the copper-colored
Malay as the red Indian. The horse, ox, and hog run through white and
red to black both in solid and party-color, and all are equally healthy;
so with the rabbit, dog, cat, and others of our domestic animals. In
wild animals, birds, reptiles, fishes, and insects, it is the same, so
that mere difference in color or combinations of color are not _prima
facie_ evidence of disease.

But some will say this may be true of animal life, but not of plant
life. That there is a strong and evident analogy, the one with the
other, is now universally admitted by physiologists. Formerly many
physiologists considered leaf variegation a disease, because it
generally ran in stripes lengthwise of the leaf or in spots. In the
former case it was supposed to originate from disease in the leaf cells
of the leaf stalk, which, as the cells grow longi