INTRODUCTION 9 



of the needed living analytic reagents. It would seem good strat- 

 egy to work out as completely as possible the requirements of 

 related more nearly autotrophic forms, if such are available; this 

 would minimize the risk of attempting to solve complex prob- 

 lems in organic nutrition while under the handicap of using a 

 basal medium inadequate in respect to essential inorganic nutri- 

 ents and known growth factors. The vast host of algae with im- 

 paired autotrophism hold forth to the vitamin enthusiasts the 

 promise of a vast arena for their talents. 



The Growth of Algae in Darkness 



One simple experimental approach to the nature of photo- 

 synthesis for some curious reason has been neglected: it is the 

 growing of algae in darkness. If we knew what was the first 

 product of photosynthesis (an entity which remains as elusive as 

 Lewis Carroll's Snark), and if organisms were permeable to this 

 substance, it should enable us to grow any photosynthetic organ- 

 ism in the absence of light — i.e. it should bypass photosynthesis. 

 This type of problem is not confined to algae: attempts to grow 

 purple bacteria anaerobically in darkness have failed (they can 

 be grown anaerobically in light, and aerobically in darkness). A 

 penetrating "first product of photosynthesis" might allow growth 

 of bacteria now termed obligately chemo-autotrophic, e.g. certain 

 species of Thiobacillus which require oxidizable inorganic sulfur 

 compounds as their energy source. It remains to be seen whether 

 such a panacea for heterotrophic growth actually exists. If exist 

 it does, it would have an importance beyond photosynthesis: the 

 analysis of the ultimate energy store for growth thereby might 

 be carried beyond the stage of the high-energy phosphate bond 

 as represented by such familiar compounds as adenosine triphos- 

 phate and phosphoglyceric acid. 



The study of photosyndiesis has technological ramifications. 

 The growing of Chlorella, once carried out entirely in the spirit 

 of theoretical inquiry, may on an industrial scale add to the 

 world's food resources. The success of this new enterprise will 

 depend on the choice of a suitable organism and a knowledge 

 of the conditions for dense growdi. Production of dense cultures 



