502 EXPERIMENT STATION EECORD. [Vol.35 



III. Changes in starch by removal of the ash and solution, M. Samec and 

 F. von Hoefft. — The three processes of removing the ash, solution, and aging 

 produce the same changes in the properties of starch, viz, a decrease in the 

 internal friction and in the influence of acids and bases on the latter. The 

 rapidity of the changes is proportional to the temperature. Simultaneously 

 with a decrease in viscosity there is an increase in the electrical conductivity 

 and a decrease in the amount of starch precipitable by alcohol. The osmotic 

 pressure is only slightly lowered, while the optical rotation is slightly increased. 

 The titratable acid is also increased. At ordinary temperatures only small 

 amounts of electrolyte can be extracted from the starch by water, but as the 

 starch grains swell the amount extracted increases. It is indicated that the 

 above observations and many others made by earlier investigators can be ex- 

 plained by the presence of an amylophosphoric acid. 



IV. The displacement of the phosphoric %pid content by a change of condition 

 of the starch and by diastatic cleavage, M. Samec. — From starch grains which 

 had been treated with potassium hydroxid a fraction containing phosphorus 

 and a phosphorus-free fraction were isolated. By the diastatic cleavage phos- 

 phorus-containing dextrins which possessed all the properties of electro-nega- 

 tive colloids were obtained. On boiling with water these dextrins were de- 

 stroyed and phosphoric acid was set free. 



V. On soluble starch, M. Samec and S. Jencic. — Starch, in being converted 

 to the soluble form, was essentially changed in structure. In most instances 

 a contraction of the starch particles was apparent, while in exceptional cases 

 there was no alteration. Most soluble starches contain phosphorus, but not 

 those prepared according to the procedure of Malfitano and Moschkoff" and 

 those prepared by heating in glycerin. On account of the variations in the 

 physicochemical characteristics of the so-called soluble starch the term is con- 

 sidered scientifically inadequate. The experimental procedures used in the 

 investigation are described in detail. 



VI. On alkali starch, M. Samec. — By the action of alkalis on starch a number 

 of different modifications could be demonstrated. The formation of two of 

 these was attributed to the action of the alkali with the phosphoric acid of 

 the starch (amylophosphate). By the continued action of the alkalis they 

 are also bound at other points in the starch molecule, forming amylates. These 

 substances finally cause a cleavage of the starch complex. 



Crystalline /3-methyl fructosid and its tetracetate, C. S. Hudson and D. H. 

 Brauns (Jour. Amcr. Chem. Soc, 38 {1916), No. 6, pp. 1216-1223). 



A fourth crystalline pentacetate of galactose and some related compounds, 

 C. S. Hudson and J. M. Johnson (Jour. Amer. Chem. Soc, 38 (1916), No. 6, 

 pp. 1223-1228). 



The determination of phosphoric acid by the uranylacetate method, D. 

 Ceispo and R. W. Tuinzing (Verslag. Landbouwk. Ondersoek. Rijkslandbouw- 

 proefstat. [Netherlands], No. 11 {1915), pp. 142-156; Landiv. Vers. Stat., 88 

 {1916), No. 1-2, pp. 131-lItl). — A modified procedure for the uranyl-acetate 

 method for the determination of phosphoric acid is described in detail. The 

 phosphoric acid is first precipitated as ammonium-magnesium phosphate, the 

 precipitate dissolved in acetic acid, and the solution then titrated with the 

 standard uranium solution. The method is applicable to the determination 

 of the various forms of phosphoric acid present in fertilizers without the 

 usual inherent difficulties. Experimental data submitted, comparing the pro- 

 posed procedure with the ofl&cial methods of Lorenz and Pemberton, indi- 



"Compt. Rend. Acad. Sci. [Paris], 150 (1910), No. 11, pp. 710, 711; 151 (1910), No. 

 19, pp. 817-819. 



