CHAPTER IV. 



EVOLUTION AND MUTABILITY OF LIVING MATTER 

 AND BRUTE MATTER. 



Supposed immobility of brute bodies Mobility and mutability 

 of the sidereal world. r. 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 environ- 

 ment Its indefinite duration Its independence of external 

 conditions The Brownian movement must be the first 

 stage of molecular motion. 3. Motion of panicles 

 Migration of material panicles 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 Con- 

 clusion Relations of the environment to the living or brute 



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, 

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