LIVING MATTER. 29 



claim our attention ; or, What can a living thing do 

 which the non-living cannot ? 



i.) All living things have spontaneous motion. The 

 non-living are passive, and only move by the compelling 

 agency of some external force, but the force which 

 moves living matter is a force which is inherent, and 

 cannot be explained by physical laws. Living matter 

 has primary energy, and can overcome inertia, but the 

 non-living are unable to originate motion. The spon- 

 taneous motions of bioplasm, or living matter, are 

 molecular, amoeboid, or wandering. 



a. Molecular movement. This must not be con- 

 founded with what has been called Brunonian motion, 

 from Dr. Robert Brown, who first described it in 1827. 

 The latter is a sort of vibration in small particles sus- 

 pended in fluid, and is supposed to be caused by cur- 

 rents formed by heat or evaporation. In the molecular 

 movements of bioplasm each particle of the mass seems 

 to be independent of the rest. As the passengers in a 

 crowded street may go the full length of the street, or 

 turn back, or stop and double as many times as they 

 wish, so do the particles move in the mass of bioplasm. 

 Up, down, across, backward, and in all directions even 

 through each other do these molecules move, each im- 

 pelled by its own inherent energy.* 



b. Amoeboid movement receives this name from its 

 resemblance to the notions of the Amoeba, described in 

 the present chapter, Sec. 2. The shape is continually 

 changing, by a portion of the body being projected from 

 the mass, or retracted, or altered in form. 



* Strieker's " Manual of Histology." 



