etter group the remainder of
the facts to which I wish to refer than by using them to illustrate
this feature of most of the later attempts at generalization on this
subject.

"First, then, these hypotheses are too partial in their tendency to
refer numerous and complex phenomena to one cause, or to a few causes
only, when all trustworthy analogy would indicate that they must
result from many concurrent forces and determinations of force. We
have all no doubt read those ingenious, not to say amusing,
speculations in which some entomologists and botanists have indulged
with reference to the mutual relations of flowers and haustellate
insects. Geologically the facts oblige us to begin with cryptogamous
plants and mandibulate insects, and out of the desire of insects for
non-existent honey, and the adaptations of plants to the requirements
of non-existent suctorial apparatus, we have to evolve the marvellous
complexity of floral form and coloring, and the exquisitely delicate
apparatus of the mouths of haustellate insects. Now when it is borne
in mind that this theory implies a mental confusion on our part
precisely similar to that which in the department of mechanics
actuates the seekers for perpetual motion, that we have not the
smallest tittle of evidence that the changes required have actually
occurred in any one case, and that the thousands of other structures
and relations of the plant and the insect have to be worked out by a
series of concurrent evolutions so complex and absolutely incalculable
in the aggregate that the cycles and epicycles of the Ptolemaic
astronomy were child's play in comparison, we need not wonder that the
common-sense of mankind revolts against such fancies, and that we are
accused of attempting to construct the universe by methods that would
baffle Omnipotence itself, because they are simply absurd. In this
aspect of them indeed such speculations are necessarily futile,
because no mind can grasp all the complexities of even any one case,
and it is useless to follow out an imaginary line of development which
unexplained facts must contradict at every step. This is also no doubt
the reason why all recent attempts at constructing 'Phylogenies' are
so changeable, and why no two experts can agree about the details of
any of them.

"A second aspect in which such speculations are too partial is in the
unwarranted use which they make of analogy. It is not unusual to find
such analogies as that bet