50 ANIMAL INDIVIDUALITY [CH. 



is here associated with chemical decomposition : the 

 result is not mere oxidized protoplasm, not protoplasm 

 at all, but various more stable and more oxidized 

 compounds. Every action thus necessitates the 

 destruction of some of the living substance, and were 

 it not for the assimilatory power, whereby it can pick 

 up materials from the outer world and force them to 

 assume a structure and arrangement like its own, all 

 protoplasm would soon vanish into nothingness. 



From these two fundamental properties of proto 

 plasm we can understand three important and almost 

 universal qualities of living things 1 . First, their 

 existence as definite bodies marked off in space and 

 separate from other bodies, no mere formless collec- 

 tion of molecules, here to-day and gone to-morrow, 

 like a liquid or a gas ; secondly their power of move- 

 ment; and thirdly their growth, due to their building 

 up more protoplasm by assimilation than what they 

 destroy in the production of energy. These three 

 are all of importance in understanding the origin of 

 organic individuality. Given cohesion of parts, your 

 primeval organism is marked off from the rest of the 

 world. Even though it may be homogeneous, no true 



1 Almost universal, for it will be seen later that mental powers 

 have made possible such organisms as an ant-colony, which is not 

 a solid whole, single and denned in space ; and growth and mobility 

 may be in abeyance for long periods, though always present in some 

 stage of an organism's life. 



