characteristics); nor between these and recognized species. "These
differences blend into each other in an insensible series, and the series
impresses the mind with an idea of an actual passage."

This gradation from species downward is well made out. To carry it one step
farther upward, our author presents in a strong light the differences which
prevail among naturalists as to what forms should be admitted to the rank
of species. Some genera (and these in some countries) give rise to far more
discrepancy than others; and it is concluded that the large or dominant
genera are usually the most variable. In a flora so small as the British,
182 plants, generally reckoned as varieties, have been ranked by some
botanists as species. Selecting the British genera which include the most
polymorphous forms, it appears that Babington's Flora gives them 251
species, Bentham's only 112, a difference of 139 doubtful forms. These are
nearly the extreme views, but they are the views of two most capable and
most experienced judges, in respect to one of the best-known floras of the
world. The fact is suggestive, that the best-known countries furnish the
greatest number of such doubtful cases. Illustrations of this kind may be
multiplied to a great extent. They make it plain that, whether species in
Nature are aboriginal and definite or not, our practical conclusions about
them, as embodied in systematic works, are not facts but judgments, and
largely fallible judgments-

How much of the actual coincidence of authorities is owing to imperfect or
restricted observation, and to one naturalist's adopting the conclusions of
another without independent observation, this is not the place to consider.
It is our impression that species of animals are more definitely marked
than those of plants; this may arise from our somewhat extended
acquaintance with the latter, and our ignorance of the former. But we are
constrained by our experience to admit the strong likelihood, in botany,