548 SCIENCE PROGRESS 



studied by Neuberg and Reinfurth (Biochem. Zeitschr. 191 8, 

 89, 365). The former author has already shown that yeast 

 contains a ferment capable of decomposing pyruvic acid into 

 carbon dioxide and acetaldehyde and that the latter compound 

 is readily reduced to ethyl alcohol during yeast fermentation. 

 It is now shown that considerable quantities of acetaldehyde 

 may be isolated from such fermentation if the latter is allowed 

 to take place in the presence of sodium sulphite which combines 

 to form the bisulphite additive compound as follows : 



C 6 H 12 6 + Na 2 S0 3 4- H 2 = C 6 H 10 O 6 (OH) . O . S0 2 Na + NaOH 

 and then 



*C 6 H 10 O 5 (OH).O.SO 2 Na -> H 2 + CH 3 C(OH).O.S0 2 NaCOOH -> 

 -> C0 2 4- CH 3 CH(OH) . O . S0 2 Na 



According to the authors' theory each glucose molecule 

 should yield one molecule of acetaldehyde and one molecule 

 of carbon dioxide, and, as a matter of fact, the yield of acetal- 

 dehyde obtained corresponded to 73-45 per cent, of the one 

 molecular proportion required by their theory. 



Some time ago Kleinstuck (Berichte, 191 8, 51, 108) put 

 forward the suggestion that carbonic acid was probably reduced 

 in the plant by hydrogen peroxide to formaldehyde according 

 to the equation 



H 2 C0 3 + H 2 2 = HCHO + H 2 4- 3O. 



Wislicenus (Berichte, 191 8, 51, 942) now points out that 

 while the reduction of carbon dioxide to formic acid, but not 

 formaldehyde, has been achieved in a variety of ways in the 

 laboratory, these ways by no means resemble those taking 

 place in the plant. On the other hand hydrogen peroxide, 

 which is a common substance in nature, can effect the reduc- 

 tion to formic acid and this is probably the first action in the 

 plant ; the further reduction of the formic acid to formaldehyde 

 he considers to be more difficult, requiring light-energy and 

 chlorophyll acting as a catalyst. Attention is drawn to the 

 fact that with the exception of the per-acids carbonic acid is 

 the only acid whose anhydride and charged or uncharged ions 

 have a peroxide structure, and the action of hydrogen peroxide 





