THE ARGUMENT 253 



ditions in the environment ; number, variety, 

 complexity, adaptability, availability, activity, 

 and richness in energy of the substances which 

 take part in the metabolic processes and in 

 the chemical and physical formation of the 

 organism ; constancy of physico-chemical con- 

 ditions, such as temperature, alkalinity, col- 

 loidal disperseness, etc., within the organism ; 

 the efficiency of many physiological processes ; 

 the availability of electrical forces, etc. 



In short, by many independent and united 

 actions the above catalogued natural char- 

 acteristics of the environment promote and 

 favor complexity, regulation, and metabo- 

 lism, the three fundamental characteristics 

 of life upon which all our discussion has 

 been based. 



II 



THE EXHAUSTIVENESS OF THE TREATMENT 



One manner of judging the completeness 

 with which different types of phenomena and 

 properties, different elements and compounds, 

 have been considered in the descriptive chap- 

 ters preceding is to glance at the several 

 departments of physical science, — chemistry, 

 mechanics, heat, sound, light, magnetism, elec- 

 tricity, and physical chemistry. 



