its embryo. Examine the recently laid egg of some common animal, such
as a salamander or newt. It is a minute spheroid in which the best
microscope will reveal nothing but a structureless sac, enclosing a
glairy fluid, holding granules in suspension. But strange
possibilities lie dormant in that semi-fluid globule. Let a moderate
supply of warmth reach its watery cradle, and the plastic matter
undergoes changes so rapid, yet so steady and purposelike in their
succession, that one can only compare them to those operated by a
skilled modeller upon a formless lump of clay. As with an invisible
trowel, the mass is divided and subdivided into smaller and smaller
portions, until it is reduced to an aggregation of granules not too
large to build withal the finest fabrics of the nascent organism. And,
then, it is as if a delicate finger traced out the line to be occupied
by the spinal column, and moulded the contour of the body; pinching up
the head at one end, the tail at the other, and fashioning flank and
limb into due salamandrine proportions, in so artistic a way, that,
after watching the process hour by hour, one is almost involuntarily
possessed by the notion, that some more subtle aid to vision than an
achromatic, would show the hidden artist, with his plan before him,
striving with skilful manipulation to perfect his work.

As life advances, and the young amphibian ranges the waters, the terror
of his insect contemporaries, not only are the nutritious particles
supplied by its prey, by the addition of which to its frame, growth
takes place, laid down, each in its proper spot, and in such due
proportion to the rest, as to reproduce the form, the colour, and the
size, characteristic of the parental stock; but even the wonderful
powers of reproducing lost parts possessed by these animals are
controlled by the same governing tendency. Cut off the legs, the tail,
the jaws, separately or all together, and, as Spallanzani showed long