THE VITAL PHENOMENA OF BACTERIA. 9! 



Chemistry of the Nutrient Substratum. 



Up to a few years ago it was considered an 

 unimpeachable tenet of biology that only the 

 plants possessing leaf-green or chlorophyl are 

 able to decompose carbon dioxide, by setting 

 free the oxygen and utilizing the carbon in the 

 construction of cell substance, starch or sugar. 

 The energy for this synthesis is afforded by 

 the sun's rays. Plants containing no chloro- 

 phyl and all animals, it was supposed, lacked 

 the power to assimilate carbon dioxide. The 

 assimilation of carbon dioxide by green plants 

 takes place through the synthesis of formal- 

 dehyde out of water and carbon dioxide ; sugar 

 arises out of the formaldehyde by polymeriza- 

 tion ; multiplication of the aldehyde formula 

 by six gives the empirical formula of grape- 

 sugar : 



I. H 2 C0 3 CH 2 + 3 

 carbonic acid, formaldehyde oxygen 



II. 6CH 2 O = C 6 H 12 O 6 

 formaldehyde, grape-sugar. 



Even before E. Fischer's remarkable achieve- 

 ments in the synthesis of the carbohydrates, 

 Low, starting with formaldehyde, had suc- 

 ceeded in building up the first sugar, called 

 formose (acrose), out of its elements. Organic 

 chemistry has now accomplished the synthesis 

 of polysaccharides like maltose and dextrine 



