86 Kansas Academy of Science. 



the acid nitrate of mercury test in Group II, as already indi- 

 cated. The remaining tests in the other groups given in the 

 table are rather well known, but the writer thinks that this 

 group method will be helpful to those interested in food 

 chemistry. 



Group Reactio})s. 



(iniuii lli-acti(ins iritli tvatcr-.soliible solutions of the (jvlntiniz- 



flrcHiiN. rcarjeiitx. in;/ n.'/riits, past)/ materials and tlticlceners. 



Blue colonition indicates starch. (Sometimes green 

 apples made into jelly will give traces of starch.) 



Group I. — Iodine solution 



Purple coloration indicates umylodextrin. 



lied coloration indicates erylhrodextrin. 



No coloration may indicate neither starch nor dextrin, 

 but mav be achroodc.rfriii. 



Filtrate, after shaking substance in solution with 

 reagent, is not clear, but cloudy. Filtrate picric 

 acid solution — yellow precipitate indicates f/e!atinr. 



(iron)) II. Millon's ov Stokes Solution i)lus drop of this reagent yields a gelatinous 



reagent (acid precipitate, soluble in excess of this reagent, which 



nitrate of mercury). indicates araciti. 



A slight white cloudy precipitate may indicate either 

 ugar-atjar or trai/aravth or both (test for traga- 

 canth as in Group IV). 



Yields a white gelatinous precipitate, which indicates 

 either aijar-anar or acacia or botli. 



Group III. Concentrated solution ^- '^- .■^"'l'" "j" ^^/V- « /«'l«tinous, opaque white 

 of sodium borate. precipitate with solution basic lead acetate. 



Ariiciii may be furtlier tested for as in Group II or 

 (irou|) IV, or by adding a solution of tannin, 

 which gives a bluish-black coloration. 



Yields brownish yellow color on heating, which indi- 

 Group IV. Solution of sodium cates traf/acanth. 



hydrate. 



Y'ields a white cloudy precipitate, indicates acacia. 



Group V. Solution of mercuric 



chloride. 



.V slight turbidity may indicate dextrin. 



.V white precipitate may indicate alhvmen and tjelatiue. 



If a concentrated water solution of the unknown is 



firoupVI. Schweitzer's reagent treated with this reagent and placed on glass slide 



(solution of under microscope, a delicate framework of cnpric 



cuprammonia ) . jiecrale is evident, sliowing a i/cctiu of fruit or 



vesietable orisin present. 



