CHAPTER IV.
EVOLUTION AND MUTABILITY OF LIVING MATTER AND BRUTE MATTER.
Supposed immobility of brute bodies—Mobility and mutability
of the sidereal world.—§ 1. The movement of particles and
molecules in brute bodies—The internal movements of
brute bodies—Kinetic conception of molecular motion—Reality
of the motion of particles—Comparison of the
activity of particles with vital activity.—§ 2. Brownian
movement—Its existence—Its character—Its independence
of the nature of the bodies and of the nature of the environment—Its
indefinite duration—Its independence of external
conditions—The Brownian movement must be the first
stage of molecular motion.—§ 3. Motion of particles—Migration
of material particles—Migration under the
action of weight; of diffusion; of electrolysis; of mechanical
pressure.—§ 4. Internal activity of alloys—Their structure—Changes
produced by deforming agencies—Slow return to
equilibrium—Residual effect—Effect of annealing; effect
of stretching—Nickel steel—Colour photography—Conclusion—Relations
of the environment to the living or brute
matter.
One of the most remarkable characteristics of a living being is its evolution. It undergoes a continuous change. It starts from something very small; it assumes a configuration and grows; in most cases it declines and disappears, having followed a course which may be predicted—a sort of ideal trajectory.
Supposed Immobility of Brute Bodies.—It may be asked whether this evolution, this directed mobility,
