THE LIVING ORGANISM 197 



and it may be found that within a period of 

 three to six months, in presence of suitable 

 energy sources and a suitable transformer 

 of colloidal character for transforming such 

 energy, the level of micro-organisms may 

 possibly be attainable. 



CHAPTER IX 



THE LIVING ORGANISM AT WORK 



In the preceding chapters a continuous 

 process of evolution has been traced out from 

 the electron to the atom, from the atom to the 

 molecule, from the molecule to the colloid, 

 and so to the confines of the organic world. 

 In the territory of living organisms, the 

 continuity remains unbroken for all living 

 creatures are made up of structural units. 

 The unit of the biologist is the living cell. 

 All living creatures are composed of one or 

 more of these units, called living cells, and 

 the biologist divides his realm into two 

 great divisions, that of the unicellular or- 

 ganisms (protozoa and protophytes), and 

 that of the multicellular organisms (metazoa 

 and metaphytes). 



