atoms--scattered throughout it in the form of dust; perhaps these are
themselves originally "points of condensation" of the vibrating
"substance," the remainder of which constitutes the ether. The atoms of
our elements arise from the grouping together in definite numbers of the
primitive atoms or atoms of mass. As the Kant-Laplace nebular hypothesis
has it, the rotating heavenly bodies separate themselves out from that
vibrating primeval cloud. A single unit among many thousands of celestial
bodies is our sun, with its planets, which originated by being
centrifugally thrown off from it. Our insignificant earth is a single
planet of our solar system; its entire individual life is a product of
the sunlight. After the glowing sphere of the earth has cooled down to a
certain degree, drops of fluid water precipitate themselves on the
hardened crust of its surface--the first preliminary condition of organic
life. Carbon atoms begin their organism-engendering activity, and unite
with the other elements into plasma-combinations capable of growing. One
small plasma-group oversteps the limits of cohesion and individual
growth; it falls asunder into two similar halves. With this first moneron
begins organic life and its most distinctive function, heredity. In the
homogeneous plasma of the monera, a firmer central nucleus is separated
from a softer outer mass; through this differentiation of nucleus and
protoplasm arises the first organic cell. For a long time our planet was
inhabited solely by such Protista or single-celled primitive creatures.
From coenobia or social unions of these afterwards arose the lowest
histones, multicellular plants and animals.

By the sure help of the three great empirical "records of creation,"
palaeontology, comparative anatomy, and ontogeny, the history of descent
now leads us on step by step from the oldest Metazoa, the simplest
pluricellular animals, up to man.[13] At the lowest root of the common
genealogy of the Metazoa stand the Gastraeadae and Spongidae; their whole