iQis] Arthur W. Thomas 397 



From 1912 to 1915 the work of Pringsheim^^ has helped to es- 

 tablish more firmly than ever the theory of the great molecular com- 

 plexity of starch. By fermentation and hydrolysis of starch, under 

 different conditions, he obtained several dextrins which were tetra- 

 and hexa-polymers of the simple dextrin molectile and similar to 

 those isolated by Schardinger i^^ 



[(CeH,o05)2]4 + 4CÄOH 

 [(CoHio05)2]3+?CAOH 



[(C6Hio05)2]2 + 2CÄOH 



which, by acetolysis and saponi- 

 fication of acetyl derivatives, 

 yield " diamylose," 



(C6Hio05)2+2H20;or 



yields " triamylose," 



"] yields triamylose, 



[(CeHio05)3]2 + 9H20 I (CeHio05)3+4H20 



From his experimental results he concludes that these dextrins 

 or " amyloses " have a ring structure, such as 



1 — ° — I 



/CH • [CH(OH)]2CH • CH(OH) ■ CHj. 

 0< ^O, ,or 



^CHa -CHCOH) • CH • [CH(OH)]2 • CH 



I O 1 



o 



CH • CH(OH)CH • CH • CH(OH)CH20H 



o< >o 



HOCHi • CH(OH)CH • CH • CH(OH)CH 



I O 1 



and that they indicate that starch itself, and the non-reducing dex- 

 trins which are not fermented by yeast, contain the ring which can 

 be opened only by special ferments. 



In the light of all the observed properties of starch, we are obliged 

 to accept the hypothesis that the molecule of this substance is large 

 and very complex. Further experimental work, perhaps from the 

 synthetical Standpoint, will doubtless throw much more light upon 

 the limits of magnitude of the molecule. 



Laboratory of Biological Chemistry, 



Columbia University, College of Physicians and Surgeons, 

 New York. 



28 Pringsheim : Berichte, 1913, xlv, p. 2533 ; 191S, xlvii, p. 2565. Landw. Vers. 

 Stat., 1914, Ixxxiv, p. 267. Naturwissenschaften, 1915, iii, p. 95- 



29 Schardinger: Zentralbl. f. Bacteriologie (II Abt.), IQOS, xiv, p. 772; 1907, 

 xix, p. 161 ; 1909, xxii, p. 198; 191 1, xxix, p. 188. 



