25 



peptides in the course of evolution, or they may have been 

 the precursors of the present sulphur bacteria. 



There is a considerable difference in size between the 

 polypeptide or sulphur-peptide spirals measuring less 

 than one millimicron in diameter, and the smallest living 

 organisms, such as tobacco leaf virus, measuring about 

 fifty millimicrons in diameter. Organisms like tobacco 

 leaf virus could not have been produced spontaneously 

 by the fortuitous play of organic molecules. Either they 

 have a long evolutionary ancestry of simpler organisms, 

 or they are in the nature of enzymes which have separated 

 from more complex organisms. If they were derived 

 from simpler organisms, then there should be representa- 

 tives of those simpler organisms in existence today, and 

 with present-day experimental methods they would have 

 been discovered if they existed. Actually, however, there 

 is hardly a single nonparasitic free-swimming submicro- 

 scopic organism known. On the other hand if such virus 

 organisms are degeneration-products of ordinary living 

 cells, then we should look for the origin of life in the 

 spontaneous formation of such cells. 



It is at this point where the experiments of Herrera are 

 of significance, for Herrera has shown that artificial cells 

 produced from comparatively simple chemicals can ex- 

 hibit all the familiar manifestations of unicellular life 

 which are generally associated with living cells, even 

 though the usual polypeptide structures may not be pres- 

 ent. It appears from Herrera 's experiments that life 

 originated, not by the gradual building up of genes and 

 complex hereditary patterns on a submicroscopic scale, 

 but rather by the generation of tiny liquid vortices 

 around granules of oxidizable material. All higher forms 

 of plant and animal life derive their energy from oxida- 

 tion of carbon compounds which were originally produced 

 by photosynthesis in green plants. This photosynthetic 

 process, however, requires the presence of chlorophyll 

 which is a highly complex compound and could only have 



