ISOMALTOSE, MALTOSE, GLUCOSE, SACCHAROSE, ETC. 147 



amount of starch was left. He made starch-paste of this residue and also of the whole 

 starch, and subjected both pastes to the action of diastase under the same conditions. 

 The former yielded 44 per cent of maltose and the latter 75 per cent. In another article 

 (Ann. d. I'lnst. Pasteur, 1899, xiii, 728, 796) he discusses especially maltodextrins and 

 Lintncr's isomaltose. Pottevin had previously found that the starch-grain is not homo- 

 geneous, and that owing to this the dextrins yielded by different parts of the grain are 

 not identical, the more resistant portions of the starch yielding dextrins which are only 

 partially convertible into maltose. He found by mixing the proper kind of dextrin in 

 proper proportion with maltose that a mixture could be obtained which seemed to be 

 absolutely identical with the maltodextrin of Brown and Morris, and he therefore holds 

 that the maltodextrin is not a chemical individual. He also contends with Brown and 

 Morris, and with Ling and Baker, that Lintner's isomaltose is not an individual. He states 

 that it is merely a mixture of a non-reducing dextrin and maltose. 



In other communications during the same year (Ann. d. LTnst. Pasteur, 1899, xiii, 

 665; Wochenschr. f. Brauerei, 1899, xvi, 641) Pottevin studied the phases of the processes 

 of starch conversion, the heterogeneous character of the starch-grain, the differences in 

 the dextrin and sugar products caused by variations in the constitution of starch, and 

 the degree of digestibUity of the several components of the grains. Ground wheat starch 

 was subjected for an hour to the action of malt extract, the solution filtered off, and fresh 

 malt extract added to the undigested starch, this solution filtered ofT, and this process 

 repeated four times, yielding four solutions. Examinations of these solutions showed 

 that each successive portion of the dissolved products was more resistant to diastase. Dif- 

 ferences in the starch-residues were also noted. Compared with the paste made from the 

 whole starch, which yielded 80 per cent of maltose, a paste made from a residue represent- 

 ing 9.5 per cent of the original starch yielded only 43 per cent of maltose. The denser 

 the part of the grain the less digestible the starch, the less digestible the dextrin product, 

 and the less the amount of the final sugar product. 



Notwithstanding that considerable evidence had already been offered to show posi- 

 tively that maltodextrins are merely mixtures of dextrins and maltose. Brown and Millar 

 (Proc. Chem. Soc. Trans., 1899, xv, 13) continued to study maltodextrin as though it 

 were an individual. They obtained a product of oxidation of maltodextrin which they 

 term maltodextrinic acid. In an appendix they gave the methods they employed to deter- 

 mine the yield of glucose by the hydrolysis of starch, maltose, maltodextrin, and maltobionic 

 acid by oxalic acid. (See page 152.) 



Syniewski (Ann. d. Chem. u. Pharm., 1899, ccix, 282), in his studies of the consti- 

 tution of starch, holds, as already stated (page 133), that the simplest product of carbinol- 

 hydrolysis is amylogen; that amylogen consists of 3 maltose residues with 1 dextrin residue, 

 which latter in turn is composed of 3 glucose residues, of which 2 are isomaltose residues. 

 In the first stage of hydrolysis of amylogen, all the maltose molecules gradually separate 

 and the dextrin residues remain behind. By the prolonged action of malt extract this 

 dextrin residue is split into isomaltose, and the isomaltose is finally con\^erted into glucose. 

 In a later article (Rozprawy akademji umiejetnosci, Ivi-akau, 1902; Jiihr. u. d. Fort, 

 d. Thierchemie, 1902, xxxii, 98) he records that malt extract acting on grenzdextrin I 

 produced maltose and another sugar, an isomer of maltose, which he terms dcxirinosc. 

 It was found to have a rotatory power of (a)D2o = +141.41, and a reducing power of 84.5 

 per cent of maltose, and its osazone had a melting-point of 152° to 153°. He states that 

 this sugar differs from Fischer's maltose and isomaltose, that it is probably identical with 

 Lintner's isomaltose, and that it finally breaks up into glucose. 



Baker (Proc. Chem. Soc. Trans., 1902, xviii, 1177) studied the products of the action 

 of barley diastase on starch. Barley diastase produced at 50° only dextrin and maltose 

 during the first IH to 2 hours, but after 24 hours there was evidence of the presence of 



