32O Cellulose 



in a recent paper by C. Doree and M. Cunningham on cara- 

 melan, the distinctive component of caramels, which are formed 

 on heating sucrose at 170-! 80 (J. Chem. Soc. iii. (1917), 

 589). The following points are established. 

 Reaction of formation : 



CijjHasOu 2H 2 O = Ci 2 H 18 O 9 caramelan 



containing four OH groups. Reactive CO groups also survive 

 and give derivatives with phenylhydrazine and semi-carbazide, 

 but with considerable further condensation, thus : 



2C ]? H t ,O d + C H u N.H 3 = C 3U H a 10 N s + 8H_O 



With boiling dilute acids there is hydrolysis to dextrose, 

 accompanied by condensation to methyl furfural and in- 

 soluble products of general formula 



CJK^On-tdaii/)* fH,0 



by which and by their reactions with halogens they are 

 identified as of the extensive series of complex derivatives 

 mentioned on p. 240. 



The authors have not established any constitutional rela- 

 tionships of these derivatives with known cyclic and hetero- 

 cyclic compounds. It is probable that the pyrone group is re- 

 presented since maltol is invariably liberated in the early stages 

 of heating the carbohydrates, and is formed from cellulose on 

 heating at 150. [A. Backe, Compt. Rend. 150, 541 ; 151, 78 ; 

 Erdmann and Schaefer, Berl. Ber. 43, 2398; Cross and Bevan, 

 J. Soc. Dyers, v. 32 (1916).] 



Physical Properties. In a recent paper (J. Soc. Dyers, 

 32} we have called attention to the relationships of the 

 cellulose and derivatives to the primary forms of energy, and 

 engaged with others in systematic study of this neglected field of 

 phenomena. With Messrs. Courtaulds and S. Judd Lewis we 

 have investigated the fluorescence phenomena first noted by 

 W. N. Hartley (J. Chem. Soc. 63-243), the ultra violet absorp- 



