LIFE 25 



that the chemical changes in protophism are precisely the same as those 

 occurring in nonliving matter, nor does it mean that none of the phenom- 

 ena associated with life is peculiar to living things. The differences, 

 however, are the outgrowth of the organization and are not due to any- 

 supernatural force which animates living bodies. 



35. Origin of Life. — The question of the origin of life on this planet 

 has been a source of speculation from early Greek times, if not before. 

 Empedocles, a Greek, about 500 B.C. presented a theory of the origin of 

 life which was that owing to attractive forces elements were combined into 

 the parts of which plants were composed, and then under the influence 

 of the same forces these parts were assembled in such a manner as to 

 form whole plants. Animals were supposed to have originated in the 

 same way as did plants, parts being formed first which later came together 

 to form the animals. This theory, fantastic as it now seems, is the first 

 definite theory of the origin of life and has earned for its author the 

 title of father of evolution. Aristotle, another Greek who lived in the 

 fourth century before Christ, had a theory more in harmony with present- 

 day conceptions. He believed that living matter originated as a jelly 

 formed at the shore of the sea and that out of this evolved first plants and 

 then animals. The simplest forms developed first, followed in order by 

 others of gradually increasing complexity up to man. 



The Mosaic, or special-creation, theory of the origin of life appears in 

 the first chapter of Genesis and was the legendary explanation accepted 

 by the Jews. According to this theory each kind of animal was created 

 in the beginning with the same character it has today, or, in other words, 

 each was the result of a special creative act. Because it is in the Bible this 

 theory has been thought of as necessarily involving the idea of a divine 

 providence and for that reason different from any other theory. As a 

 matter of fact, however, the conception of a deity need not be associated 

 with any one of the theories of the origin of life to the exclusion of its 

 association with others. One who believes in a creative and ruhng spirit 

 or force in the universe will attribute to it the creation of life no matter 

 what his theory may be as to how creation actually occurred, while one 

 who does not believe in such a force will leave it out of whatever scheme of 

 creation he holds. 



Spontaneous generation implies the repeated creation of life whenever 

 favorable conditions occur. A theory of spontaneous generation was 

 held by the Greeks, who believed that various living forms found in fresh 

 water died off each fall and were recreated each spring. The observations 

 of Aristotle and others showed this belief to be incorrect in the case of 

 many familiar forms. Gradually the number of animals thought to be 

 spontaneously generated was reduced, until, in 1680, Redi, an Italian, 

 effectively disproved the spontaneous-generation theory held at that time 

 when he showed that fly maggots were not spontaneously generated in 



