18 EASY LESSONS IN VEGETABLE BIOLOGY. 



spring from its own internal energy. So far from 

 being caused by external influence, its movements are 

 often in direct opposition to gravity, or any other 

 force which we may imagine to act upon it. 

 The motions of bioplasm are of three kinds : 



(1) Inherent motions of the individual particles 

 among themselves. Each particle is as much alive as 

 the whole mass, and the movements of each are spon- 

 taneous. If a thread or filament of bioplasm be ex- 

 amined in a powerful microscope, the motions of the 

 particles may be observed by the granules of formed 

 material (Sec. 5, Chap. II) which may be scattered 

 through the mass. " 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 impelled by its own inherent energy." ' 



Observe another motion of bioplasm : 



(2) Constant change of shape. A piece of bio- 

 plasm never remains at rest. If unconfined, its exter- 

 nal appearance or shape is continually changing. 

 This has been called annceboid motion, from the name 

 given to one of the simplest forms of living beings 

 known, the Amoeba. 



Fig. 1. This appears to be simply a piece of bio- 



* " Science of Life." 



