I9I5] Arthur W. Thomas 395 



The elaborate work of Synklewski ends with this hypothetical 

 configuration f or the starch molecule, the size of which(C6Hio05)36, 

 is only about one sixth as large as that proposed by Brown and 

 Morris, (C6Hio05)2oo' The experimental work of Brown and 

 Morris is not nearly so extensively appHed to the question at issue 

 as that of Synkiewski, and on that account one might be incHned 

 to give preference to Synkiewski's suggested molecule; but it must 

 be borne in mind that Synkiewski's hypothesis rests entirely on two 

 dextrins, protodextrin I and protodextrin II, the one formed by 

 malt diastase in cold Solution and the other in hot Solution. He 

 assumes that these dextrins of different molecular weight are dif- 

 ferent individuals and that both are present in the starch molecule 

 simultaneously. This assumption is open to doubt, however, since 

 malt diastase does not appear to have any different influence in 

 hot and cold Solutions other than that due to difference in rate of 

 hydrolytic action. 



Since Synkiewski's work appeared there have been several 

 papers of minor Import dealing with this same topic. During the 

 same year there was published by Hale-^ a review of work pre- 

 viously reported about the Constitution of starch; also an account 

 of his own ideas and the results of a study of starch iodides. He 

 constructed a molecular formula embodying all the good features 

 of former workers. From his own work on starch iodide he con- 

 cluded that the size of the starch molecule might be at least 

 (CcHio05)i8, because he had obtained an iodide of starch contain- 

 ing 4.38 percent of iodine; expressing the formula (C6Hio05)i8l. 

 This formula does not merit much consideration because, with our 

 present knowledge of colloidal chemistry, we are prone to regard the 

 blue complex formed by starch and iodine as a special colloidal phe- 

 nomenon. 



In 1904, Kladiaschwili^* treated starch with formic acid and 

 obtained a mono-formyl derivative which seemed to indicate by the 

 freezing-point-depression-method in chloracetic acid and phenol 

 Solutions the formula (C7Hio06)6. There is danger, however, 

 that this derivative is a hydrolytic product of starch. 



23 Haie: School of Mines Quarterly, 1902, xxiv, p. 125. 



24 Kladiaschwili : /. Russ. Phys. Chem. Soc, 1904, xxxvi, p. 905. 



