f
anywhere truly exemplified in plants, it is only in the lowest and
simplest, where the being is a structural unit, a single cell,
memberless and organless, though organic,--the same thing as those cells
of which all the more complex plants are built up, and with which every
plant and (structurally) every animal began its development. In the
ascending gradation of the vegetable kingdom individuality is, so to
say, striven after, but never attained; in the lower animals it is
striven after with greater, though incomplete success; it is realized
only in animals of so high a rank that vegetative multiplication or
offshoots are out of the question, where all parts are strictly
members and nothing else, and all subordinated to a common nervous
centre,--fully realized, perhaps, only in a conscious person.

So, also, the broad distinction between reproduction by seeds or ova and
propagation by buds, though perfect in some of the lowest forms of life,
becomes evanescent in others; and even the most absolute law we know in
the physiology of genuine reproduction, that of sexual co-operation,
has its exceptions in both kingdoms in parthenogenesis, to which in the
vegetable kingdom a most curious series of gradations leads. In plants,
likewise, a long and most finely graduated series of transitions leads
from bisexual to unisexual blossoms; and so in various other respects.
Everywhere we may perceive that Nature secures her ends, and makes her
distinctions on the whole manifest and real, but everywhere without
abrupt breaks. We need not wonder, therefore, that gradations between
species and varieties should occur; the more so, since genera, tribes,
and other groups into which the naturalist collocates species are
far from being always absolutely limited in Nature, though they are
necessarily represented to be so in systems. From the necessity of the
case, the classifications of the naturalist abruptly define where Nature
more or less blends. Our systems are nothing, if not definite. They
are intended to express differences, and perhaps some of the coarser
gradations. But this evinces, not their perfection, but their
imperfection. Even the best of them are to the system of Nature what
consecutive patches of the seven colors are to the rainbow.

Now the principle of gradation throughout organic Nature may, of
course, be interpreted upon other assumptions than those of Darwin's
hypothesis,--certainly upon quite other than those of m