/l/ Aseptically reared on synthetic diets. /2/ Deprived of normally present Intracellular symblotes. 

 /3/ Vitamin H^. jh/ May be replaced by betalne. /5/ A generic term Including cyanocobalamin (vitamin 

 'S)\2^ ^^^ ^^^ hydrogenation product known variously as 62^23 °'' Bi2b '"'^'^ '^s approximately the same bio- 

 logical activity. /6/ Folic acid is not a chemical entity but a generic term for pteroylglutamic acid 

 (folacln), vitamin M, vitamin B^, factor U, L. easel factor, Norlte eluate factor. /7/ Used here as a 

 generic term for nicotinic acid (niacin) and nicotinic acid amide (niacinamide). /8/ Includes pyridox- 

 lne, pyridoxal, pyridoxamine. /9/ Cholesterol may be required by all the forms listed but is shown as 

 required only in those forms in which specific experiments have Indicated its need. /lO/ Unidentified 

 substances obtained from yeast. 



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