34 Can Science Explain Life? 



acids or salts. At higher temperatures the aldol 

 may have been converted into crotonaldehyde 

 CH 3 • CH : CH • CHO by the loss of a molecule of 

 water and the latter may have become oxidized to 

 crotonic acid CH 3 CH : CH • COOH. Since cro- 

 tonic acid contains a double bond, it could easily 

 have been converted into the corresponding amino 

 acid CH 3 ■ CH 2 • CHNH 2 • COOH either by direct 

 addition of ammonia or by combination with some 

 oxide or acid of nitrogen and subsequent reduc- 

 tion. The amino acid molecules may then have 

 been converted into polypeptides by the action of 

 dry heat, and the latter, under suitable conditions, 

 may have formed the first spirazines. 



The individual spirazines thus produced may 

 then have developed into more complex structures 

 by folding over upon themselves as will be de- 

 scribed more in detail later. Endwise growth of 

 such structures may then have taken place either 

 by assimilation of complete amino acid molecules 

 which may have been present in the surrounding 

 medium, or by the spontaneous synthesis of the 

 alpha amino acid structure from the carbon di- 

 oxide, water, and nitrogen compounds in the sur- 

 rounding medium, such synthesis having probably 

 been effected by the catalytic action of the spira- 

 zines themselves in the presence of sunlight. 

 Although there is no experimental evidence that 



