28 KINETIC ENERGY AND LIFE. 



KINETIC ENERGY AND LIFE. 



The forms of kinetic energy that are active in organisms, namely, 

 plants and animals, are precisely the same as those that are recognizable 

 in inanimate matter. A so-called ''vital energy," which is supposed to 

 act as a special form of force of peculiar character and cause and control 

 the vital phenomena of living organisms, does not exist. The forces 

 of all matter, both organic and inorganic, are bound up in their smallest 

 particles, the atoms. As, however, the smallest particles of organ- 

 ized matter are generally united in a most complex manner, in con- 

 trast to the ordinarily much simpler constitution of inorganic bodies, 

 the forces inherent to the smallest particles of organism will appear in 

 much more complicated phenomena and combinations, and as a result 

 the explanation of the vital phenomena in the organism by the simple 

 principles of physics and chemistry is rendered extremely difficult 

 and in many respects appears impossible. 



Metabolism as an Index of Life. A special form of interchange in 

 matter and energy appears peculiar to the living organisms of the earth. 

 This consists in the ability to adapt themselves to the materials of 

 their environment, and to assimilate them, so that for a time they 

 represent integral parts of the living being, later again to be given off. 

 The complete chain of these phenomena is designated "metabolism,' 1 

 which consists accordingly in ingestion, assimilation, reduction and 

 excretion. 



It has already been suggested that metabolism differs in character 

 in animals and in plants. As a matter of fact, this is, as has been shown, 

 actually the case in animals and plants typically and characteristically 

 developed. There is, however, a large group of organisms that in their 

 complete organization exhibit such atypical development that they 

 must be considered as undifferentiated fundamental forms of organisms. 

 They cannot be recognized as either plants or animals, but represent 

 the simplest form of animate matter. These organisms, as the earliest 

 and most primitive forms, have been designated protists. It must be 

 assumed absolutely that these also have a simple metabolism as a condi- 

 tion of life, but with respect to this adequate observations are wanting. 



