One is so accustomed to the axiom that all life originates from pre- 

 existing life that he seldom considers the question of how life began 

 in the first place. The ancients solved the problem with the idea of 

 the spontaneous generation of such complex organisms as flies and 

 mice from nonliving matter. But these, as well as more sophisticated 

 ideas, were laid to rest by the experiments of Redi and Pasteur. As 

 a result, however, the basic question. How did life originate?, was 

 brought into focus. Without some type of spontaneous generation, 

 how can the origin of the myriad entities which are called "alive" be 

 explained? Often this problem has been confused by the tendency 

 to equate life with the properties of highly complex organisms. The 

 contrast between a bird and a rock or between a bacterium and an 

 iron filing is self-evident. Indeed, it is so striking that the difference 

 between the hving and the nonliving could be misconstrued as one of 

 kind rather than one of degree. 



The great majority of biologists believe that there is no significant 

 discontinuity between the living and the nonliving, even though they 

 may not agree on a definition of "life" or even upon the "properties" 

 of life. Many obstacles may be avoided merely by viewing life as a 

 special property of matter at a certain stage of complexity and not 

 attempting a rigorous definition. At least it can be said that living 

 systems handle energy in a regulative manner so as to establish an 

 energy potential between the organism and its environment; cer- 

 tainly one of the most fundamental properties of life is the continu- 

 ous and directed movement of electrons among the complex mole- 

 cules of which living organisms are made. It is important to note 

 that these energy transformations are precisely controlled. The 

 regulated release of an amount of energy, which uncontrolled would 

 cause a mild explosion, results in what is thought of as life. In addi- 

 tion, living systems have the property of reproducing themselves. 

 Thus when the problem of the origin of life is considered, answers 

 must be sought to the questions of how the systems that extract and 

 utilize energy from the environment could arise and how they could 

 replicate. There seems to be a sort of twilight zone between the 

 extremes of living and nonliving, an area in which these terms may 

 not be applicable. In this zone of viruses, nucleic acids, and spe- 

 cialized sorts of colloids some of the answers to our questions may 

 be found. 



It does not seem likely that the spontaneous origination of life can 

 be observed at the present time. If new life did appear spontane- 

 ously, it would probably quickly be eliminated by modern hetero- 



