INSOLUBLE CARBOHYDRATES OR MARC. ~ (3 
Another paper by Frémy“ appeared in 1848. The facts contained 
in the previous paper are retold, and new onesare given. ‘The article 
ignores the work of every other chemist working in the field, and 
appears thirty-five years later, practically without change, in the 
Encyclopédie Chimique. ae 
Neubauer? reported concerning arabin, precipitated by alcohol from 
eum arabic solution (found by Scheibler to be identical with metapec- 
tic acid). | 
Frémy° obtained metapectic acid by boiling beet mare with milk of 
lime. | 
Stude” published work which was largely confirmatory of work 
already done by others. The existence of pectose was denied, the 
author believing that the pectin bodies in tissues existed as calcium 
pectate. No data of any kind are given in the paper. 
Scheibler’ published two papers of much interest in which the for- 
mation of sugar from pectin is described. Metapectic acid was pre- 
pared from beet marc, and this by acid hydrolysis yielded a crystal- 
lizable sugar which he called arabinose. This was followed in 1873/7 
by a report of further work dealing with arabinose and metapectic 
acid. ‘The sugar was the same whether prepared from beet mare or 
from gum arabic. The method of preparing metapectic acid used by 
him was as follows: 
Beet pulp was repeatedly washed and macerated in cold 85 per cent 
alcohol. The pressed-out residue was thrown into boiling water, 
alcohol boiled out, potassium hydroxid added to a strong alkaline 
reaction, and the solution heated for a long time on a water bath. 
The product was then filtered, saturated with carbon dioxid, eoncen- 
trated by evaporation, filtered, and the filtrate acidulated with acetic 
or hydrochloric acid. The pectic acid was then precipitated with 
alcohol and the crude product purified by repeated solution in water and 
precipitation with alcohol. Finally, the concentrated aqueous solu- 
tion was poured into a small high cylinder, a little alcohol was added, 
and the mixture was allowed to stand several weeks. During this 
time there was formed a precipitate which carries nearly all the ash, 
and the filtrate yielded arabic acid of fine quality. | 
Girard’ determined the pectin in gum tragacanth. 
Kirchner and Tollens” hydrolyzed quince gum by boiling with 1.25 
per cent of sulphuric acid for varying periods of time. In one exper- 
« Ann. chim. phys., 1848, [3] 24: 5; J. f. prak. Chem., 1848, 45: 385; Ann. Chem. 
(Liebig), 1848, 67: 257. 
bJ. prak. Chem., 1854, 62: 193. 
¢Compt. rend., 1859, 49: 561. 
@ Ann. Chem. (Liebig), 1864, 131: 241. 
¢ Ber. d. chem. Ges., 1868, 1: 58, 108. 
Ff Ibid., 1873, 6: 612. 
9 Ibid., 1875, 8: 340. 
h Ann. Chem. (Liebig), 1875, 175: 205. 
