JANTJABT 27, 1911] 



SCIENCE 



141 



synthesis of fructose was effected first from 

 acrolein and later from glycerol. The 

 whole subject of the action of alkalis upon 

 formaldehyde has been taken up in recent 

 years by Euler,^^ who has made a careful 

 study of the course of the reaction and the 

 conditions affecting it. It is especially in- 

 teresting to note that this investigator has 

 succeeded in synthesizing a sugar from for- 

 maldehyde through the agency of calcium 

 carbonate as a condensing agent. The in- 

 terest here lies chiefly in the fact that the 

 formation of sugar may be effected by a 

 substance universally distributed in the 

 soil. It is interesting to note that Euler 

 in this way showed that the simplest of 

 sugars, viz., glyeolaldehyde, is produced as 

 an intermediate product. The principal 

 sugar finally formed is a pentose, namely, 

 (dZ)-arabino-ketose. Lob''^ has recently ef- 

 fected similar condensations by the use of 

 zinc as well as zinc carbonate. 



Equally important are the results which 

 have been obtained through the action of 

 ■the silent electric discharge. Berthelot,^^ 

 in this way, produced from a mixture of 

 carbon dioxide, water and hydrogen a sub- 

 stance having the properties of a carbo- 

 hydrate. With carbon monoxide and hy- 

 drogen he obtained a similar product which 

 appeared to be a polymer of formaldehyde. 

 Likewise Slosse,^* from carbon monoxide 

 and hydrogen, obtained a crystalline, fer- 

 mentable sugar. 



The investigations of Lob^^ in which he 

 produced formaldehyde directly from car- 

 bon dioxide and water vapor through the 

 influence of the silent electric discharge 

 have already been referred to. Under the 

 same conditions this investigator has been 

 able to polymerize the aldehyde so formed 

 '^JSer. d. chem. Oesell., 39, pp. 39, 45. 

 ^Biochem. Zeit., la, p. 78. 

 ■» Compt. rend., 126, p. 610. 

 •* Bull, de I. Ac. roy. de Belg., 35, p. 547. 

 ^Zeit. f. Elektrochem., 12, p. 282. 



into glyeolaldehyde and this in turn into a 

 hexose. The formation of a sugar from 

 carbon dioxide and moisture has thus been 

 effected through the agency of the energy 

 of the silent electric discharge. It may be 

 added that patents have been taken out for 

 the synthetic production of sugar under 

 this general method. 



Taken as a whole, the results of the in- 

 vestigations would seem to corroborate 

 Baeyer's original assumptions. The trans- 

 formation of carbon dioxide and water into 

 formaldehyde and the subsequent polym- 

 erization of this into a sugar under con- 

 ditions approximating those existing in the 

 plant may be regarded as accomplished. 

 While the evidence advanced can not be 

 regarded as showing beyond doubt the 

 presence of free formaldehyde in the plant, 

 yet it is plain that the failure to detect its 

 presence can not be regarded as fatal or as 

 even opposed to Baeyer's theory. In fact, 

 one would naturally expect that because 

 of its great activity, its polymerization 

 would keep pace with its formation and 

 that the tests for its presence would 

 therefore be negative. On the other 

 hand, it can not be doubted but that plants 

 have the power to directly assimilate for- 

 maldehyde. While certain objections 

 have been urged against Baeyer's hypoth- 

 esis and other radically different ones^^ 

 have been advanced, yet it would seem 

 from the present indications that further 

 progress in our knowledge of the forma- 

 tion of carbohydrates in the vegetable 

 kingdom probably will be made along the 

 lines originally pointed out by Baeyer. 



In the study of the results of these in- 

 vestigations one is impressed with the 

 large number of conflicting statements. 

 Certainly one would not turn to these re- 



" Etard, " La Biochem. et les chlorophylles," 

 Paris, 1906 ; Loew, " Chem. Energ. in leb. Zell.," 

 1906. 



