76* STUDIES ON APPLES. 



trated at the lowest possible temperature. Alcohol was added and 

 resulting gelatinous precipitate after filtering off was dissolved in 

 water. After digesting for one hour with 1 per cent hydrochloric acid 

 at 00 C., and filtering, two precipitates were formed on fractional 

 precipitation of the filtrate with alcohol. The first, after repeated 

 solution and precipitation with water and alcohol respectively, was a 

 white weakly acid mass, precipitated by barium chlorid and lead ace- 

 tate, of strongly dextro-rotatory power ([]"+ 167.4), and yielding 

 20 per cent of mucic acid on oxidation. The second, after purifica- 

 tion in the same way, was an amorphous white substance, precipitated 

 by lead acetate, but not by barium chlorid, showing less dextro- 

 rotation ([<*]/>=+ 123.8), and gave no mucic acid on oxidation, but 

 yielded with phloroglucin and hydrochloric acid an intense color 

 reaction denoting pentoses or pentosans. 



Tromp de Haas and Tollens" gave the ultimate composition and 

 products of hydrolysis by sulphuric acid of pectins from many 

 source's. Their results showed that the relation of hydrogen and 

 oxygen in these bodies was nearl} T 1 to 8, as required by the carbohy- 

 drate formula, and that the pectin bodies which they studied contained 

 no complex which gave rise to dextrose, but that complexes were pres- 

 ent which yielded pentose sugars and galactose on hydrolyzing with 

 acids. 



'Pollens 6 in a later paper says that pectin bodies may probably be 

 regarded as glucosides, since the acid reaction, combination with bases, 

 and slightl} 1 - higher oxygen-hydrogen ratio of extracted pectins indi- 

 cate the presence of carboxyl groups. The pectin in the plant may 

 not have acid properties, but may exist as a lactone. 



Andrlik^ discusses the action of dilute hydrochloric acid in the cold 

 on beet marc. A pectin of specific rotatory power ([<*]/, = +214. 4 to 

 220) was extracted, and purified by repeated precipitation with alco- 

 hol. The longer the acid acted on the beet marc, the more insoluble 

 in water was the pectin dissolved. 



Bourquellot and HerissejV* and later Bourquellof alone, studied the 

 extraction of pectins with hot water, and the effect of two enzyms on 

 the dissolved bodies. A 1 per cent solution of pectins from gentian 

 root was gelatinized by a solution of pectase within 40 minutes, and 

 also by limewater, sodium h} T droxid followed by hydrochloric acid, 

 neutral and basic lead acetates, ferric chlorid, magnesium sulphate, and 

 ammonium sulphates, but not by sodium sulphate. The pectin was 

 not reducing and was dextro-rotatory ([]#= +82.3). Acidified water 

 extracted a more dextro-rotatory bod} T ([<*]# +145.3). 



Ann. Chem. (Liebig), 1895, 286: 278. 



6 Ibid., 1895, 286: 292. 



cZts. Zucker-Ind. Bohm., 1894, 19: 101, through Chem. Centrbl. 1895, 66: 1, 833. 



d J. pharm. chim., 1898, [6] 7: 473; 1898, [6] 8: 145; 1899, [6] 9: 281. 



Compt. rend., 1899, 128: 1241. 



