s not accomplished by distention only, but by apposition to every part
both external and internal; each of which acquires by animal appetencies
the new addition of the particles which it wants. And hence the enlarged
parts are kept similar to their prototypes, and may be said to be extended;
but their extension must be conceived only as a necessary consequence of
the enlargement of all their parts by apposition of new particles.

Hence the new apposition of parts is not produced by capillary attraction,
because the whole is extended; whereas capillary attraction would rather
tend to bring the sides of flexible tubes together, and not to distend
them. Nor is it produced by chemical affinities, for then a solution of
continuity would succeed, as when sugar is dissolved in water; but it is
produced by an animal process, which is the consequence of irritation, or
sensation; and which may be termed animal appetency.

This is further evinced from experiments, which have been instituted to
shew, that a living muscle of an animal body requires greater force to
break it, than a similar muscle of a dead body. Which evinces, that besides
the attraction of cohesion, which all matter possesses, and besides the
chemical attractions of affinities, which hold many bodies together, there
is an animal adhesion, which adds vigour to these common laws of the
inanimate world.

8. At the nativity of the child it deposits the placenta or gills, and by
expanding its lungs acquires more plentiful oxygenation from the currents
of air, which it must now continue perpetually to respire to the end of its
life; as it now quits the liquid element, in which it was produced, and
like the tadpole, when it changes into a frog, becomes an aerial animal.

9. As the habitable parts of the earth have been, and continue to be,
perpetually increasing by the production of sea-shells and corallines, and
by the recrements of other animals, and vegetables; so from the beginning
of the existence of this terraqueous globe, the animals, which inhabit it,
have constantly improved, and are still in a state of progressive
improvement.

This idea of the gradual generation of all things seems to have been as
familiar to the ancient philosophers as to the modern ones; and to have
given rise to the beautiful hieroglyphic figure of the [Greek: proton oon],
or first great egg, produced by NIGHT, that is, whose origin is involved in
obscurity, and animated by [Greek: eros],