50 



THE BIOLOGICAL APPROACH 



GENERATIO SPONTANEA 



In literature, this inorganic photosynthesis of 'organic' compounds is 

 sometimes called generatio spontanea. Generatio spontanea has, how- 

 ever, for a long time been a sort of catch-all for a mode of origin 

 of life on earth which was not understood, which it was not possible 

 to study, or which was something akin to, or just the opposite of, 

 creation. At present, now that the possible modes of origin of life 



COE 



C+0-^C02C0* 



HoO- 



CH-j+H *"H2jC2Hg,C2H4,C2H2 



H + OH* H+OH •^H2,02,H202 



ads 



NH2 + H NH2 + H---N2,H2,N2H4 



1 — \ — r 

 9 



10 



1200 



1295 

 Xe 



1400 



8 



\ I I \ \ I 

 7 6 5eV 



1650 1850 2000 2537 X 



1470 

 Xe 



Fig. 8. Spectral ranges of photochemical sensitivity for gases (from 

 A. N. Terenin, 1959). Oxygen is seen to absorb the ultraviolet light 

 from a wavelength of 1850 A downwards. The energy values of the 

 corresponding light quanta, expressed in electronvolts, is seen to rise 

 from about 7 eV for light of 1800 A to 10 eV for light of 1200 k. In 

 this region the other gases mentioned are photochemically active, as is 

 indicated by the hatching and cross-hatching. The asterisks indicate at 

 what wavelength the radicals in question start emitting light, a pheno- 

 menon without significance for the synthesis of larger molecules, but 

 important for their recognition during the experiment. The dashed ar- 

 rows indicate the spectral ranges at which composite molecules, formed 

 from atoms and radicals are built up. The two Xenon lines of 1295 A 

 and 1470 A indicate the strong monochromatic radiation of the xenon 

 lamp, which Groth used as early as 1938 in experiments of this kind. 



