Synthesis of Sugars. 387 



Cultures supported fresh crops of fungi for weeks, but remained 

 optically inactive throughout. 



Chemosynthesis of sugar from COg and water. — It is well known 

 ihat powdered magnesium Avill cause traces of formaldehyde to 

 .appear slowly in a solution of carbon dioxide in water. 250 c.c. 

 of water with 2 grains of Magnesium Avere charged with carbon 

 <lioxide under pressure for 3 weeks at 12 to 15° C, and then boiled 

 in a condensing Hask for 2 days. After then boiling to a small 

 l>ulk and filtering, the filtrate was evaporated nearly to dryness 

 ;and excess of hot absolute alcohol added. The filtrate on evapo- 

 rating to dryness left a gummy residue readily soluble in water, 

 -optically inactive and containing reducing hexose and pentose 

 tgugar, one of the former being apparently a levulose and giving the 

 "ketohexose test with resorcin, while the pentose gives the usual 

 5)recipitate with phloroglucin and HCl soluble in amyl alcohol. 



Summary . 



The polymerization of formaldehyde to sugar by alkalies and 

 lalkaline carbonates has been investigated. 



The main conditions for a high proportion of sugar are appro- 

 priate dilution and a temperature of 100° C. to 110° C. The by- 

 products are formates and luethyl alcohol mainly. At low tem- 

 peratures little or no sugar is produced. 



The most rapid reaction is produced by sodium hydrate. In 

 the presence of a neutral calcium salt, the a.mount of sugar con- 

 <iensation is greatly increased, less alkali is required and less 

 formate produced. Neutral Barium and Strontium salts are less 

 •effective as condensing katalytic agents. 



The best method is by running 7 to 8 c.c. of 3.5 % sodium 



liydrate into 2o0 c.c. of 0.8 % calcium formate contMiniiig 5 c c. 



•of 40 % formaldehyde while boiling in a condensing flask. The 



reaction is completed in a few minutes, and as soon as a pale 



j-ellowish tinge appears, all the formaldcliyde has disappeared. 



The sugar mixture is optically inactive, and contains reducing 

 pentoses and reducing fermentable hcxoses. Carbon dioxide and 

 water are readily polmerized to sugar by the aid of magnesium. 

 The production of calcium tartiate during sugar synthesis has not 

 been confirmed, and was possibly due to the use of an oxidized 

 sample of formaldehyde. 



