190 DIGESTION 



cannot be given. Neumeister, recognizing erythrodextrin as the first 

 splitting-product from the amylodextrin (so named because with iodine it 

 gives a red coloration), supposes that at least three forms of dextrin 

 are successively produced, which, because they give us color with iodine, 

 have received the name achroodextrins. These he named, respectively, 

 alpha-achroodextrin, beta-achroodextrin, and gamma-achroodextrin. 

 Neumeister 's theory of this hydrolysis, therefore, may be represented in 



a table, thus: 



Starch (amylose). 



Soluble starch (amylodextrin). 



Erythrodextrin. Maltose. 



.1, 



,. ( . ...I 

 a Achroode 



lextrin. Maltose. 



(3 Achroodextrin. Maltose. 



7 Achroodextrin (maltodextrin). Maltose. 

 Maltose. 



Musculus and Gruber corroborated this supposition, but still the 

 proof that the three achroodextrins named are proper substances, stable 

 and constant in composition, is far from conclusive. Ptyalin, unlike the 

 dilute mineral acids, is unable to continue the splitting-reaction of the 

 maltose into glucose or grape-sugar. Maltose, however, is not absorbable 

 through the intestinal wall, but is inverted into dextrose before absorp- 

 tion into the blood takes place. This result is produced by the hydro- 

 chloric acid of the stomach, and especially by the enzyme maltase (or 

 glucase) of the succus entericus. Were we to represent the hydrolytic 

 cleavage in the simplest possible equation, it would be 



3(C 6 H ]0 5 ) + 2(H 2 0) = C 6 H 10 5 + C ]2 H 2 A,. 



Starch. Dextrose. Maltose. 



But this is misleading in a sense, for the reaction is very much more com- 

 plex than the equation would indicate, starch, for example, not being 

 C 6 H 10 O 5 but some multiple of that. If, then, we take m, n, and p as the 

 unknown co-efficients of the starch, water, and dextrin molecules con- 

 cerned, respectively, we have (Moore) : 



(C 6 H 10 5 )m + (H 2 0)n = (C 12 H a O u ) (H 2 O) + (C 6 H 10 O 5 )p 



as the most precise formula of diastatic action at present obtainable, 

 and this is much more descriptive of the process than the previous 

 formula given. 



