INSOLUBLE CARBOHYDRATES OR MARC. (Ek 
chiefly of iron phosphate. It was insoluble or only slightly soluble in 
hot water, but readily dissolved in alkali to a clear solution. 
The author discussed the difficulties in preparing pure metallic 
derivatives for analysis, which he considered to be best prepared from 
the alkali salt of pectic acid and a soluble salt of the metal. It is dif- 
ficult to avoid inclosing excess of alkali or salt in the resulting jellies. 
This source of error was removed by squeezing out the salts and wash- 
ing with water. The author so prepared and analyzed the calcium, 
barium, sodium, and silver salts, obtaining the formula C,,H,,O,,. 
Pectinic acid was named and studied by Chodnew, who obtained it 
by boiling beet mare with hydrochloric acid, precipitating by alcohol, 
and washing with alcohol and ether. It differed from pectin in having 
a slight acid reaction. This author discussed the question of whether 
pectic acid exists as such in plants. Beet mare yielded no pectic acid 
toammonium hydroxid, so that pectic acid may exist here in combined 
form, perhaps joined to calcium. But the mare after twice boiling 
out with hydrochloric acid (removal of pectinic acid?) still yielded to 
potassium hydroxid a body which on precipitating with acid showed 
all the properties of pectic acid. The author considered then that 
there existed in beet marc, not pectic acid, but a mixture of pectinic 
acid and a newly found acid—iiberpectic acid—which he stated.was 
changed by potassium hydroxid into pectic acid, and was insoluble in 
ammonia. These two pectin bodies, pectinic acid and iiberpectic acid, 
he considered to be the sources of pectic acid as usually prepared. 
Similar results were obtained from apples, pears, and red and yellow 
beets. It was suggested that Frémy’s acid, obtained from unripe 
gooseberries by boiling with acid, might be pectinic acid. 
In support of the theory that pectin bodies exist combined with cal- 
cium in beet marc, the author described an experiment in which beet 
mare was allowed to stand with dilute hydrochloric acid. It became 
soft and translucent. On washing and adding a very little limewater, 
it regained its opacity and harshness. 
Metapectic acid (cf. Frémy, p. 69), prepared by Chodnew by boiling 
pectin with potassium hydroxid, gave precipitates with acids and salts 
on standing, anda jelly with alcohol. Its lead salt treated with hydro- 
gen sulphid gave a black colloidal solution from which it was impossible 
to separate the lead sulphid. Its properties differed from those given by 
Frémy in being not a penta-valent acid, not deliquescent in the air, and 
forming no soluble salts with caleium or barium. Pectic acid boiled for 
_two hours with dilute mineral acid did not dissolve entirely to metapec- 
tie acid as Frémy states. The author carefully described the phenom- 
ena which occurred as the acid was boiled with dilute sulphuric acid 
salts. The solution soon became colored red, and reducing with silyer 
and copper; formic acid and carbon dioxid were formed in small quan- 
tity, the former recognized by itsodor, and the latter by limewater. As 
