STARCH: A CAPITAL DISCOVERY 



It has long been established that starch, the first visible product 

 of the assimilation of carbon dioxide by plants, is resolved by 

 the enzymes known collectively as diastase into a mixture of 

 so-called dextrins and maltose, the isomeride of saccharose or 

 cane sugar ; acids have a similar effect but by their action the 

 starch is ultimately reduced to glucose. Starch is represented 

 empirically by the formula C 6 H 10 O 5 but it must be supposed that 

 a considerable number of such units are present in its mole- 

 cule, each derived from a molecule of glucose. The dextrins 

 apparently are all intermediate in complexity between starch 

 and maltose ; they are ill-characterised substances and with one 

 exception have been described as non-crystalline. 



Needless to say, knowledge of the structure of starch is of 

 primary importance but chemists hitherto have met with little 

 success in their attempts to determine the manner in which the 

 C 6 units are associated. At last, however, light is coming and 

 again we are helped by the humble Bacillus. It was pointed 

 out by F. Schardinger, in 1903, that crystalline products might 

 be obtained from starch by the action of certain Bacteria. 

 Schardinger then isolated the active organism {Bacillus macerans') 

 and with its aid succeeded in obtaining an a- and a /3-dextrin, 

 which he described somewhat fully. 1 



Messrs. H. Pringsheim and H. Langhans, who have under- 

 taken the further study of these compounds, have arrived 

 recently at results of a striking character. 2 



Schardinger's a-dextrin dissolves in water to the extent of 

 179 and the /3-dextrin of 176 per cent, at the laboratory tempera- 

 ture. The /3-compound is at least of the complexity indicated 

 by the formula (C 6 H 10 O 5 ) 6 ; cryoscopic determinations show that 



1 F. Schardinger, Zeitschr. f. d. Untersuch. d. Nahrungs- u. Genussmittel, 6, 

 874(1903). Wiener klinische Wochenschrift (1904) Nr. 8. Zentralbl.f.Bakterio- 

 logie und Parasitenkunde, II. Abt. 14, 772 (1905); 19, 161 (1907); 22,98(1909); 

 29, 188 (191 1). 



1 Berichte d. deut. chem. Ges. 1912, 2533. 



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