INSOLUBLE CARBOHYDRATES OR MARC. 67 



C. A. Browne, jr.," determined starch by the following method: 

 One hundred grams of finely grated pulp were washed upon a muslin 

 filter with repeated quantities of cold water until the filtrate amounted 

 to two liters, the muslin being squeezed after each addition of water. 

 The washed out starch was allowed to settle, the supernatant liquid 

 poured off, and the starch collected on a hardened filter and washed 

 with water. The starch was determined by the official diastase method 

 with the exception that sodium hydroxid instead of sodium carbonate 

 was used for neutralization after the hydrolysis with hydrochloric acid. 

 The residue on the filter was also run by the diastase method, in case 

 it showed any reaction with iodin. Not more than 0.1 to 0.2 per cent 

 of starch, calculated on the original bulk, was ever found in this residue. 



Lindet 6 used the following procedure, depending on the solvent 

 action of salicylic acid on starch: One hundred grains of pulp were 

 placed on a niter and washed with 5 to 6 liters of water, to which a 

 little mustard oil was added to prevent fermentation. The filter and 

 contents were introduced into a flask with 250 cc of water, 2 grams of 

 salicylic acid, and 100 grams of salt, and boiled for three hours under 

 a return condenser. The volume of the resulting solution was meas- 

 ured and the solution polarized, corrections being made for the volume 

 of solid constituents. The percentage of starch was calculated from 

 the rotation observed, the rotatory power of the dextrin being taken 

 as (^)/> =H-177. The method was checked by hydrolyzing the dextrin 

 obtained to dextrose and determining the latter by means of Fehling's 

 solution. 



II. INSOLUBLE CARBOHYDRATES OR MARC. 



PECTIN BODIES. 



HISTORICAL REVIEW. 



Good reviews of the literature and descriptions of pectins have been 

 made by von Lipmann, c Tollens, rf Hebert, e and by Mangin/ the latter 

 having taken up the work from the botanist's point of view. In 

 order to bring the subject before American investigators the present 

 review is presented. 



The pioneer work in the field was done by Braconnot/ who found 

 pectins very widely distributed in plants, occurring in the dahlia, in 

 * Jerusalem artichokes, celery, carrots, onions, in stems and leaves of 



J. Am. Chem. Soc., 1901, 23: 869. 



&Ann. agron., 1894, 20: 5. 



Chemie der Zuckerarten, 1895, p. 924-936. 



d Handbuch der Kohlenhydrate, 1888 ed., p. 242-246, 1895 ed., p. 242-247. 



e Ann. agron., 1900, 26: 34-50. 



/J. hot., 1891, 5: 400, 440; 1892, 6: 12. 



g Ann. chim. phys., 1825 [2], 28: 173. 



