THE ORIGIN OF LIFE 146 



stitutes a phenomenon of which the inorganic world affords no 

 parallel: 



With these facts in mind, we can hardly fail to be amused 

 whenever certain simple chemical reactions obtained in vitro 

 are hailed as ''clue to the origin of life." When it was found, 

 for instance, that, under certain conditions, an aldehyde 

 (probably formaldehyde) is formed in a colloidal solution of 

 chlorophyll in water, if exposed to sunlight, the discovery 

 gave rise to Bach's formaldehyde-hypothesis; for Alexis Bach 

 saw in this reaction "a first step in the origin of life." As for- 

 maldehyde readily undergoes aldol condensation into a syrupy 

 fluid called formose, when a dilute aqueous solution of for- 

 maldehyde is saturated with calcium hydroxide and allowed 

 to stand for several days, there was no difficulty in conceiving 

 the transition from formaldehyde to the carbohydrates; for 

 formose is a mixture containing several hexose sugars, and 

 Fischer has succeeded in isolating therefrom acrose, a simple 

 sugar having the same formula as glucose, namely: CsHioOs. 

 Glyceraldehyde undergoes a similar condensation. In view 

 of these facts, carbohydrate-production in green plants was 

 interpreted as a photosynthesis of these substances from water 

 and carbon dioxide, with chlorophyll acting a sensitizer to 

 absorb the radiant energy necessary for the reaction. The 

 first step in the process was thought to be a reduction of 

 carbonic acid to formic acid and then to formaldehyde, the 

 latter being at once condensed into glucose, which in turn 

 was supposed to be dehydrated and polymerized into starch. 

 From the carbohydrates thus formed and the nitrates of the 

 soil the plant could then synthesize proteins, while oxidation 

 of the carbohydrates into fatty acids would lead to the forma- 

 tion of fats. Hence Bach regarded the formation of formal- 

 dehyde in the presence of water, carbon dioxide, chlorophyll, 

 and sunlight as the "first step in the production of life." 

 Bateson, however, does not find the suggestion a very 

 helpful one, and evaluates it at its true worth in the following 

 contemptuous aside: "We should be greatly helped," he says, 



