onal" process, and the
symmetry is undoubtedly the result of a "balance of forces," but to say so
is a truism. The question is, what is the cause of this "nutritional
balancing"? It is here contended that it must be due to an internal cause
which at present science is utterly incompetent to explain. It is an
internal property possessed by each living organic whole as well as by each
non-living crystalline mass, and that there is such internal power or
tendency, which may be spoken of as a "polarity," seems to be demonstrated
by the instances above given, which can easily be multiplied indefinitely.
Mr. Herbert Spencer[195] (speaking of the reproduction, by budding, of a
Begonia-leaf) recognizes a power of the kind. He says, "We have, therefore,
no alternative but to say that the living particles composing one of these
fragments have an innate tendency to arrange themselves into the shape of
the organism to which they belong. We must infer that a plant or animal of
any species is made up of special units, in all of which there dwells the
intrinsic aptitude to aggregate into the form of that species; just as{185}
in the atoms of a salt, there dwells the intrinsic aptitude to crystallize
in a particular way. It seems difficult to conceive that this can be so;
but we see that it _is_ so." ... "For this property there is no fit term.
If we accept the word polarity as a name for the force by which inorganic
units are aggregated into a form peculiar to them, we may apply this word
to the analogous force displayed by organic limits."

Dr. Jeffries Wyman,[196] in his paper on the "Symmetry and Homology of
Limbs," has a distinct chapter on the "Analogy between Symmetry and
Polarity," illustrating it by the effects of magnets on "particles in a
polar condition."

Mr. J. J. Murphy, after noticing[197] the power which crystals have to
repair injuries inflicted on them and the modifications they undergo
through the influence of the medium in which they may be formed, goes on to
say:[198] "It needs no proof that in the case of spheres and crystals the
forms and the structures are the effect, and not the cause, of the
formative principles. Attraction, whether gravitative or capillary,
produces the spherical form; the spherical form does not produce
attraction. And crystalline polarities produce crystalline structure and
form; crystalline structure and form do not produce crystalline polarities.
The same is not quite so evident of organ