0 
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? used the following procedure, depending on the solvent 
action of salicylic acid on starch: One hundred grains of pulp were 
placed on a filter 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 (@)p=+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. 
HistoricaAL REvIEw. 
Good reviews of the literature and descriptions of pectins have been 
made by von Lipmann,’ Tollens,? Hebert,’ 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. 
b Ann. agron., 1894, 20: 5. 
¢ Chemie der Zuckerarten, 1895, p. 924-936. 
@ Handbuch der Kohlenhydrate, 1888 ed., p. 242-246, 1895 ed., p. 242-247. 
é Ann. agron., 1900, 26: 34-50. 
J J. bot., 1891, 5: 400, 440; 1892, 6: 12. 
g Ann. chim. phys., 1825 [2], 28: 173. 
