SO PO RE PEE ET 
in 
fo Sty tanta ls 
UY) 
( 
INSOLUBLE CARBOHYDRATES OR MARC. ( 
if 
In this connection the following quotation from Cross and Bevan“ 
is of interest: 
It appears, therefore, generally, that the pectic group are compounds of carbo- 
hydrates of varied constitution with acid groups of undetermined constitution, asso- 
ciated together to form molecular complexes, more or less homogeneous, but entirely 
resolved by the continued action of simple hydrolytic agencies; and the pectocellu- 
loses are substances of similar character in which the carbohydrates are in part 
replaced by nonhydrolyzable celluloses. The general characteristics of the pecto- 
celluloses are therefore these: they are resolved by boiling with dilute alkaline solu- 
tions into cellulose (insoluble) and soluble derivatives of the noncellulose (pectin, 
pectic acid, metapectic acid); they are gelatinized under the alkaline treatment; 
they are ‘‘saturated compounds,’’ not reacting with the halogens, nor containing 
any groups immediately. allied to the aromatic series. 
Later in the same volume, page 221, Cross and Bevan refer to the 
parenchymatous tissue of fruits, Fesliey roots, etc., as being typical 
pectocelluloses. , 
This suggests the possibility that all insoluble pectin bodies occur- 
ring in the vegetable world are really in combination with cellulose 
and belong to the group of pectocelluloses. This idea is in part borne 
out by the results previously published by several writers and con- 
firmed by the results given on page 88, in which it is seen that iasolu- 
ble pectin bodies are changed to soluble form by boiling with water. 
If such insoluble pectin bodies, usually called pectoses, are really 
pectocelluloses, this action by which they are converted into soluble 
form Is really a splitting off of the pectin group from the cellulose 
complex. 
In this connection should be noted the recent work by Mangin,? in 
which attention is called to deposits which that writer considered to 
be caleium pectate between the cell walls of plant tissues. His con- 
clusions, however, have recently been disputed by Devaux,’ who 
asserts that this insoluble deposit was not really calcium pectate but 
true pectose. If it is found that the substance now known as pectose 
is really a pectocellulose, it is suggested by the writers that the latter 
term be employed to designate it and that the use of the term pectose, 
which is a misnomer and altogether misleading, be discontinued. 
ANALYSES OF APPLE MARC. 
PREPARATION OF SAMPLE. 
Fully ripe Rhode island Greening apples were taken from cold 
storage, wiped off, quartered, cores and bruised places removed, and 
passed through a meat grinder. The pulp was then exhausted with 
water by pressing out by hand in cloth bas wel successive jsouenoins 
a Gomes 2d ed., 1903, p. 217, 
6 Loe. cit. (see p. 78). 
“Mémoires de la société des sciences physiques et naturelles de Bordeaux, 1903 
[6 ]2 5-90: 
