olume appearing in 1802.

In the second part of the _Philosophie zoologique_ he considers the
physical causes of life, and in the introduction he defines nature as
the _ensemble_ of objects which comprise: (1) All existing physical
bodies; (2) the general and special laws which regulate the changes of
condition and situation of these bodies; (3) finally, the movement
everywhere going on among them resulting in the wonderful order of
things in nature.

To regard nature as eternal, and consequently as having existed from all
time, is baseless and unreasonable. He prefers to think that nature is
only a result, "whence, I suppose, and am glad to admit, a first cause,
in a word, a supreme power which has given existence to nature, which
has made it as a whole what it is."

As to the source of life in bodies endowed with it, he considers it a
problem more difficult than to determine the course of the stars in
space, or the size, masses, and movements of the planets belonging to
our solar system; but, however formidable the problem, the difficulties
are not insurmountable, as the phenomena are purely physical--_i.e._,
essentially resulting from acts of organization.

After defining life, in the third chapter (beginning vol. ii.) he treats
of the exciting cause of organic movements. This exciting cause is
foreign to the body which it vivifies, and does not perish, like the
latter. "This cause resides in invisible, subtile, expansive,
ever-active fluids which penetrate or are incessantly developed in the
bodies which they animate." These subtile fluids we should in these days
regard as the physico-chemical agents, such as heat, light, electricity.

What he says in the next two chapters as to the "orgasme" and
irritability excited by the before-mentioned exciting cause may be
regarded as a crude foreshadowing of the primary properties of
protoplasm, now regarded as the physical basis of life--_i.e._,
contractility, irritability, and metabolism. In Chapter VI. Lamarck
discusses direct or spontaneous generation in the same way as in 1802.
In the following paragraph we have foreshadowed the characteristic
qualities of the primeval protoplasmic matter fitted to receive the
first traces of organization and life:

"Every mass of substance homogeneous in appearance, of a gelatinous
or mucilaginous consistence, whose parts, coherent among themselves,
will be in the state nearest fluidity, but will have only a
consistence s