102 PHYSIOLOGY OF ALIMENTATION. 



trin is formed from the starch and is subsequently changed 

 into sugar, or whether dextrin and sugar are formed simul- 

 taneously, is not yet settled. If the former is the correct 

 view, it would be expressed by the formula 



Ci2H2oOio =C 12 H 2 oOio. (1) 



Starch Dextrin 



. (2) 



Dextrin Water 



If the second theory, that of Museums, is the correct one, 

 the following equation would hold: 



Starch Water Maltose Dextrin 



The majority of authors also believe that the dextrin formed 

 is not all of the same kind, that, in other words, several dex- 

 trins are formed, which have been distinguished by different 

 names. The basis for this belief lies in the fact that the 

 dextrins obtained at different stages in the saccharification 

 of starch are not converted into maltose with the same rapidity 

 when acted upon by amylase under normal circumstances 

 or in the presence of acids, salts, various organic substances, 

 etc. It seems probable, however, that these differences rest 

 more upon physical than upon chemical characteristics of 

 the dextrin. Dextrin belongs to the* group of substances 

 known as colloids, 1 and the properties which have been 

 considered characteristic of different dextrins might readily 

 characterize one and the same chemical substance in differ- 

 ent physical states. A dextrin solution in which the particles 

 are finely divided would, for example, be more rapidly con- 

 verted into sugar than one in which the suspended particles 

 are coarser. 



^ Amylase may be used as a type to illustrate some of the 

 characteristics of a ferment. Amylase accelerates a chemical 



1 See Chapter XIV, Part 2, 



