Living Organisms 735 



their accumulation in the water or damp earth. Later, still further 

 actions followed because of the lability of the nitrogen compounds until 

 poorly organized, diflfuse substances were formed which still later 

 changed into living protoplasm. 



5. Troland's Theory. — At some moment in the earth's history a small 

 quantity of a certain autocatalytic enzyme spontaneously appeared in 

 the warm ocean waters. It then combined with a drop of rather inactive 

 oily liquid, thereby increasing its rate of activity and size until the drop 

 became split into smaller globules, giving rise to a substance having the 

 power of continued and indefinite growth. 



6. Osborn's Theory. — Osborn assumes that the air, water, and earth 

 had all the necessary chemical elements and that they arranged them- 

 selves into water, nitrates, and carbon dioxide at a temperature between 

 6° and 89° C, long before sunlight could penetrate the various vapors 

 of the atmosphere. He suggests that these materials so formed captured 

 and transformed the electric energy of the chemical elements constitut- 

 ing living protoplasm and this property probably later developed only 

 in the presence of heat energy from the sun or earth. First, there was 

 a grouping of the several "life elements," and then by mutual attraction 

 their arrangement in a state of colloidal suspension, with numerous 

 actions and reactions, until an organic, living organism was formed which 

 was distinct from the various other aggregations of the nonliving or in- 

 organic matter previously brought together and held by forces of gravity. 



7. Transcendental Theory (Creation). — This religious answer sug- 

 gests that life was created by an agent working outside the realms of 

 matter and science. 



III. CONTINUITY OF LIFE 



If, as we now believe, all life arises and has arisen from preexisting 

 life (biogenesis), then the stream of life is continuous from the beginning 

 of life to the present time (Figs. 350 and 351 ) . The Hfe of an individual 

 organism is merely one Hnk in the endless chain extending from the dis- 

 tant past to the future. After a study of the metamorphosis and life 

 cycles of various animals and plants, we see that life transferred to the 

 offspring by one or more parents is carried by that offspring through its 

 various stages of development to maturity, when it in turn will pass life 

 on to its offspring. This is possible because of the continuity of living 

 substance between parents and their offspring (Chapter 34). Reproduc- 

 tion is for the purpose of continuing the life of a particular species after 



