ERYTHRODEXTRIN, ACnROODEXTRIN, GRENZDEXTRIN, ETC. 131 



Chlodounsky and Sulc (Sitzungsber. d. k. bohm. Gesellsch. d. Wissensch., 1896; 

 Jahr. ii. d. Fort. d. Tiercliemie, 1896, xxvi, 67) subjected starch-paste to the action of an 

 extract of pancreas for 18 daj's at 38°. The greater part of the starch was unchanged. 

 The sohition was filtered and concentrated to a sj'rup, and then precipitated with 80 per 

 cent alcohol, the precipitate being designated dextrin I. The alcohol was evaporated, 

 and the solution again reduced to a syrup, and then precipitated with 90 per cent alcohol, 

 yielding (kxtrin II. By subsequent treatment osazones were obtained. In the dexlrin I 

 fraction only achroodextrin could be found; and from the dextrin II fraction no dextrin 

 could be obtained that was suitable for experiments, even after repeated purification. 

 In other preparations with the glycerine extract of pancreas they state that erythro- 

 dextriu could be detected. 



A method for preparing pure commercial dextrin was reported by Berge (Bull. Assoc. 

 Beige d. Chimistes, 1879, x, 444), which consists of subjecting raw starch to a temperature 

 between 80° and 115° in an atmosphere of gaseous sulphur dioxide. By this means Berge 

 prepared dextrin containing as little as 0.95 per cent of sugar. He also used sulphurous 

 acid in a liquid state, when he found that saccharification begins at about 100,° the most 

 favorable conditions being a temperature of 1.35° to 140°, a pressure of 6 atmospheres, 

 and 25 per cent of starch in a 3 to 6 per cent solution of sulphurous acid. Saccharification 

 was complete in about an hour. 



Petit (Compt. rend., 1897, cxxv, 309, 355) prepared dextrin by subjecting boiled 

 starch to the action of diastase at 70° for about half an hour, when it yielded a constant 

 red reaction with iodine. He obtained the dextrin in the form of a white powder, which 

 was non-hygroscopic and did not yield an osazone. This dextrin by further treatment 

 was converted into saccharine products which differ somewhat according to the decomposing 

 agent, the period of action, and the temperature. 



Lintner (Chem. Zeit., 1897, xxi, 737, 752) extended liis previous investigations on 

 the chemistry of starches, especially with reference to the dextrins and their isolation. 

 He goes on to state that the purity of the product can be fairly well determined by the 

 application of cryoscopic and osazone tests, together with the rotatory and reducing powers, 

 and the iodine reactions. Dilute alcohol he regards as the best agent for the isolation of 

 the different dextrins, and he found that alcoholic barium hydroxide and alcohoUc calcium- 

 liy(hoxide solutions tend to bring about decomposition. The lower the molecular weight 

 of the dextrin the greater the solubility, as a rule; but the dextrins were found to react 

 upon one another when in solution, affecting each other's solubility. When strong alcohol 

 is to be used he advises that only some of the total amount of alcohol be added to a hot 

 dextrin solution, and that to this mixture be added, with brisk agitation, hot alcohol of 

 definite volume and strength, and that the preparation then be set aside to cool to room 

 temperature. 



The products of the restricted action of diastase when boiled starch is acted upon 

 at 70° were studied by Ling and Baker (Proc. Chem. Soc, 1897, clxxiii, 3; Jour. Chem. 

 Soc, Lxxi, 1897, 508). Besides maltose they separated a substance which was isomeric 

 with maltose (which they beheve probably consists of maltose and a simple form of dextrin 

 already described by them), together with two forms of maltodextrin. One of the malto- 

 dextrins they look upon as being identical with the maltodextrin of Brown and Morris, 

 while the other they identify with Prior's aclu-oodextrin II. They hold that there is 

 ample evidence to justify the conclusion that starch is broken down into a series of 

 maltodextrins of decreasing rotatory power and molecular weight and increasing reducing 

 power, all of these bodies having optical and reducing powers equivalent to mixtures of 

 starch and maltose. 



A number of erythrodextrins were obtained by Young (Journal of Physiology, 1897-8, 

 XXII, 401) by subjecting soluble starch to the actions of dilute acids or enzymes, arresting 



