70 STUDIES ON APPLES. 
Fromberg“ corroborated some of Frémy’s work. Beet mare was 
boiled with dilute sodium carbonate in order to extract the pectin as 
the sodium salt of pectic acid, and the acid was precipitated by addi- 
tion of excess of hydrochloric acid to the solution. On boiling a 
solution of pectic acid made faintly alkaline, a solution of the salt of 
metapectic acid was usually formed, from which no precipitate formed 
on acidifying. 
Chodnew” added materially to this literature of the pectin bodies. 
He considered that little was established in regard to their properties 
or constitution. 
Pectin was prepared from pears, which were ground up, boiled, and 
the juice filtered first through linen, then through paper. . The bright 
filtrate was precipitated with alcohol, and the filtrate washed with 
alcohol and ether and squeezed out, whereby it lost its gelatinous 
character and became lke woody fiber (Holztfaser). This pectin was 
soluble, easily powdered, neutral in reaction, and gave no precipitate 
with calcium or barium chlorid, or with ammonium hydroxid. Lead 
acetate, basic lead acetate, copper sulphate, limewater, and potassium 
hydroxid gave the gelatinous precipitates. This pectin contained 
from 8.5 to 8.76 per cent ash. 
Pectin from apple juice was studied in a similar way. It was also 
high in ash, but was largely freed from ash by precipitating by 
alcohol from an acid solution. This pectin gave the combustion 
figures: Carbon, 43.70 and 43.79; hydrogen, 5.63 and 5.41; oxygen, 
50.67 and 50.80; and differed from pear pectin by not dissolving clear 
in water. Pectin is given as C,,H,,O,,. 
Pectic acid was studied, the author first giving a résumé of previous 
work, particularly that of Frémy. It was prepared as follows, mostly 
from white beets: The mare was boiled with dilute potassium hydroxid 
for a quarter to half an hour, and filtered first through cloth and then 
through paper, the last filtration being very slow. It was considered 
better, after filtering through cloth, to precipitate the free acid and 
dissolye in ammonium hydroxid, which yields easily filterable solu- 
tions. The pectic acid was precipitated by hydrochloric or nitric 
acid washed with acidulated water, then with water containing alcohol, 
and finally with alcohol, and pressed out by hand. Alcohol is neces- 
sary in the wash water, for as the mineral acid diminishes in concen- 
tration, the pectic acid begins to stop up the pores of the filter. With 
uleohol the precipitate gradually lost its gelatinous property and 
became like woody fiber. It was colorless and easily powdered. By 
long drying at 120° C. it became yellow-colored. It was obtained 
nearly free from ash by repeatedly precipitating with alcohol from 
water solution made slightly acid with nitrie acid. So prepared it 
burned without swelling, yielding 1 per cent of ash, which consisted 
“Ann. Chem. (Lrebig), 1843, 48 : 56. )Ibid., 1844, 51: 355, 
