THE WONDERS OF LIFE 



chemical pfocesses in organic and inorganic bodies. In 

 this we emphasize our opposition to vitahsm, which sees 

 in the direction of plasma-movement the supernatural 

 influence of a mystical vital force or of some ghostly 

 "dominant" (Reinke). We agree with Ostwald, who 

 also reduces these complex movements to the play of 

 energy in the plasm — that is to say, in the last instance 

 to modifications of chemical energy. In regard to the 

 visible movements of the living things which concern 

 us at present, we must first distinguish passive and ac- 

 tive, and subdivide the latter into reflex and autonomous. 

 Many movements of the living organism which the 

 inexpert are inclined to attribute to life itself are purely 

 passive ; they are due either to external causes which do 

 not proceed from the living plasm, or to the physical 

 composition of the organic but no longer living sub- 

 stance. Purely passive movements, which play an im- 

 portant part in bionomy and chorology, comprise such as 

 the flow of water and the rush of the wind; they cause 

 considerable changes of locality and "passive" migra- 

 tions of animals and plants. Purely physical, again, is 

 what is known as the Brownian molecular movement 

 which we observe with a powerful microscope in the 

 plasm of both dead and living cells. When very fine 

 granules (for instance, of ground charcoal) are equally 

 distributed in a liquid of a certain consistency, they are 

 found to be in a constant shaking or dancing movement. 

 This movement of the solid particles is passive, and is 

 due to the shocks of the invisible molecules of the fluid 

 which are continually impinging upon each other. In 

 the rhizopods — the remarkable protozoa whose unicellu- 

 lar organism sheds so much light on the obscure wonders 

 of life — ^we notice a curious streaming of the granules in 

 the living plasm. Within the cytoplasm of the amoebae 

 particles travel up and down in all directions. On 

 the long thin plasma-threads or pseudopodia which 



260 



