74 STUDIES ON APPLES. 



iment the time of boiling 1 was seven hours, and the reaction product 

 was examined as follows: It was filtered and the insoluble residue on 

 the filter weighed. Sulphuric acid was removed from the filtrate with 

 barium carbonate, and sugar and soluble solids were determined. 

 They found 28.3 per cent of nonhydrolyzed material, 39.8 per cent of 

 sugar (calculated as dextrose), and 46.36 per cent of gum; in all, 114.46 

 per cent. 



Reichardt a prepared from carrots pararabin, a bod} T somewhat dif- 

 ferent from Scheibler's arabic acid, but readily converted into it, and 

 showing a carbohydrate percentage composition of C 12 H 22 O U . 



Barfoed 6 studied changes of various arabic acids from soluble into 

 insoluble form by standing in alcohol or on drying. 



Scheibler found that beet marc, previously extracted with alcohol, 

 yielded to water a body which could be obtained ash free, and which 

 possessed a rotatory power of over -j-200 . 



Von Lippman^ described a body, ^-galactan, of high rotatory power 

 from the scums of sugar manufactured from unripe beets, possibly 

 very similar to the metapectic acid obtained by Scheibler. 



Muntz * suggested that the galactose complexes so widely distributed 

 in plants were probably the sources of the galactose radical in lactose 

 in milk. 



Battut/ Chevron/ and Pellet 7 ' discussed the influence on the polari- 

 zation of sugar of the dextrorotatory pectin dissolved on boiling 

 sugar-free beet marc with water. Basic lead acetate precipitates it 

 completely, thus disposing of the question of its interference with 

 polarimetric measurements. 



Weisberg* confirms the view of Scheibler that gelatinous hot water 

 extract from -beet marc exhausted by alcohol was a pectin. On heat- 

 ing with water the acidity of the solution gradually increased. By 

 sulphuric acid hydrolysis of the pectin, he also obtained a furfurol 

 yielding sugar (arabino.se). 



Wohl and Van Niessen * 'discuss the w.ork of Scheibler. Pectins of 

 beet marc were considered to be insoluble in water, unless rendered 

 soluble by hydrolysis, and to be slowly changed to soluble forms by 

 hot water, and much more rapidl\ r by acids and alkalis. For example, 



Ber. d. chem. Ges., 1875, 8: 807. 

 & J. prak. Chem., 1875, [2] 11: 186. 

 cNeue Zts. f. Rubenz., 1879, 3: 341. 

 <*Ber. d. chem. Ges., 1887, 20: 1001. 

 Ann. chim. phys., 1887 [6], 10: 566. 

 /Sucre indigene, 1888, 32: 285, 311, 333, 357, 415, 456. 



</Neue Ztg. f. Rubenz., 1888, 20: 169. Sucre beige, 1888, 13: through Chem. 

 Ztg. R., 1888, 12: 82. 

 h Sucre indigene, 1888, 32: 390. 

 *Neue Zts. f. Rubenz., 1888, 21: 325. 

 *Zts. Ver. d. Zucker-Ind., 1889, 39: 924. 



