med to do so when many and
remote, we cannot account for those innumerable changes in organization
which are implied when, for advantageous use of some modified part, many
other parts which join it in action have to be modified.

Further, as increasing complexity of structure, accompanying increasing
complexity of life, implies increasing number of faculties, of which
each one conduces to preservation of self or descendants; and as the
various individuals of a species, severally requiring something like the
normal amounts of all these, may individually profit, here by an unusual
amount of one, and there by an unusual amount of another; it follows
that as the number of faculties becomes greater, it becomes more
difficult for any one to be further developed by natural selection. Only
where increase of some one is _predominantly_ advantageous does the
means seem adequate to the end. Especially in the case of powers which
do not subserve self-preservation in appreciable degrees, does
development by natural selection appear impracticable.

It is a fact recognized by Mr. Darwin, that where, by selection through
successive generations, a part has been increased or decreased, its
reaction upon other parts entails changes in them. This reaction is
effected through the changes of function involved. If the changes of
structure produced by such changes of function, are inheritable, then
the re-adjustment of parts throughout the organism, taking place
generation after generation, maintains an approximate balance; but if
not, then generation after generation the organism must get more and
more out of gear, and tend to become unworkable.

Further, as it is proved that change in the balance of functions
registers its effects on the reproductive elements, we have to choose
between the alternatives that the registered effects are irrelevant to
the particular modifications which the organism has undergone, or that
they are such as tend to produce repetitions of these modifications. The
last of these alternatives makes the facts comprehensible; but the first
of them not only leaves us with several unsolved problems, but is
incongruous with the general truth that by reproduction, ancestral
traits, down to minute details, are transmitted.

Though, in the absence of pecuniary interests and the interests in
hobbies, no such special experiments as those which have established the
inheritance of fortuitous variations have been made to ascerta