, all-powerful so long as it does not leave the
domain of the ideal, let us submit a very modest reality: the fall of a
grain of sand, the pendular movement of a hanging body. The machine no
longer works, or does so only by suppressing almost everything that is
real. It must have an ideal material point, an ideal rigid thread, an
ideal point of suspension; and then the pendular movement is translated
by a formula. But the problem defies all the artifices of analysis if
the oscillating body is a real body, endowed with volume and friction;
if the suspensory thread is a real thread, endowed with weight and
flexibility; if the point of support is a real point, endowed with
resistance and capable of deflection. So with other problems, however
simple. The exact reality escapes the formula.

Yes, it would be a fine thing to put the world into an equation,
to assume as the first principle a cell filled with albumen and by
transformation after transformation to discover life under its thousand
aspects as the geometrician discovers the ellipse and the other curves
by examining his conic section. Yes, it would be magnificent and enough
to add a cubit to our stature. Alas, how greatly must we abate our
pretensions! The reality is beyond our reach when it is only a matter of
following a grain of dust in its fall; and we would undertake to ascend
the river of life and trace it to its source! The problem is a more
arduous one than that which algebra declines to solve. There are
formidable unknown quantities here, more difficult to decipher than the
resistances, the deflections and the frictions of the pendulum. Let us
eliminate them, that we may more easily propound the theory.

Very well; but then my confidence in this natural history which
repudiates nature and gives ideal conceptions precedence over real
facts is shaken. So, without seeking the opportunity, which is not my
business, I take it when it presents itself; I examine the theory of
evolution from every side; and, as that which I have been assured is the
majestic dome of a monument capable of defying the ages appears to me to
be no more than a bladder, I irreverently dig my pin into it.

Here is the latest dig. Adaptability to a varied diet is an element of
well-being in the animal, a factor of prime importance for the extension
and predominance of its race in the bitter struggle for life. The most
unfortunate species would be that which depended for its existence on a
d