INSOLUBLE! CA&BOH^DKAT^S OR MARC. 75 



water dissolved about one-third of beet marc in about thirty hours, 

 while dilute oxalic acid dissolved nearly 45 per cent in four hours, 

 heating on the water bath in each case. The method used for obtain- 

 ing' mucic acid from marc is as follows: 35 grams of beet pulp con- 

 taining 4.3 per cent of marc were extracted with alcohol, the alcohol 

 removed, and the marc thoroughly dried. The marc was then heated 

 with 17 cc of nitric acid (sp. gr. 1.15) for two hours in a boiling water 

 bath in a 100-cc flask. The reaction product was cooled, diluted to 

 mark, filtered, and 50 cc evaporated to 3 cc. After standing forty-eight 

 hours, 94.5 mg of mucic acid had separated, equal to 0.53 per cent of 

 original pulp, or 12.4 per cent, calculated to marc, which equals 16.2 

 per cent of galactose or 14.6 per cent of galactan. 



Herzfeld" considered -pec tins as combinations of araban and galac- 

 tan, not separable by known means, and recognized by yielding fur- 

 furol on the one hand and mucic acid on the other. He was able to 

 concentrate the furfurol yielding a complex by precipitating the 

 ammonia solution of parapectin with calcium chlorid, the calcium salt 

 yielding as high as 40 per cent of furfurol. From ripe oranges he i 

 obtained an inactive pectin which was, however, precipitable by neu- 

 tral lead acetate, distinguishing it from Fremy's pectin. 



Bertrand and Mallevre b discussed the effect of the ferment pectase 

 on pectin, and the wide distribution of that enzym in plants. It is 

 especially abundant in leaves, and it has been possible to prepare it 

 from this source. It can only coagulate pectins in the presence of 

 alkaline earth salts, forming salts of pectic acid. In acid fruits it is 

 present in soluble form, but its action is inhibited by the free acid. 



Ullik^ found pectic acid to have a high rotatory power (about [ar]i>= 

 + 186 to 300) and to form easily soluble, alkali salts diatysing 

 readily, while the other salts are insoluble and gelatinous. He sepa- 

 rated up to 80 per cent of mucic acid, but noted that pectic acid from 

 different sources and prepared by different methods behaved very 

 differently in regard to yield of mucic acid; some giving the above 

 high percentage, while others gave very little, and still others no 

 mucic acid whatever. Those yielding high percentages of mucic acid 

 showed the highest rotatory power (up to [^]^= + 300), and on 

 h} r drolysis passed over principally into galactose, while those showing 

 low percentages of mucic acid gave exclusively or almost exclusively 

 arabinose. Such characteristics are indicated by the author in case 

 of pectin from beet marc. 



Sugar-free beet marc was allowed to stand several days with 1 per 

 cent of i^drochloric acid, then pressed out, and the filtrate concen- 



Zts. Ver. d. Zucker-Ind., 1891, 41: 295, 667. 

 &Compt. rend., 1894, 119: 1012; 1895, 120: 110; 1895, 121: 726. 

 C 6sterr.-Ung. Zts. Zucker-Ind. Landw. 21: 546; 28: 268, through Chemie tier 

 Zuckerarten, von Lippmau, 1895, p. 927, 928. 



