REPORT OF THE CHEMIST. 153 
5. EKsSviMATION OF OLL.—Exactly two grams of the powdered grain 
are extracted by repercolation with Squibb’s stronger ether. The time 
required for complete extraction is not over three hours, and probably 
less would be as well. The ether is carefully evaporated and the oil 
dried at 100° C. until two weighings do not vary more than .001 gram. 
6. ESTIMATION OF SUGARS AND OF ALBUMINOIDS SOLUBLE IN ALCO- 
HOL OF 80 PER CENT.—The grain remaining after the removai of oil is 
dried, and is then treated by repercolation for twelve to fifteen hours 
with warm alcohol of 80 per cent., by weight. 
The alcoholic solution is evaporated, dried, and weighed. This residue 
= sugar, albuminoids, and ash. It is then treated for several hours 
with cold water, which removes all the sugar, and in case of wheat a 
very slight amount of albuminoids. This liquid is evaporated, dried at 
110° C., weighed, ignited, and again weighed. The difference between 
the first and second weighings represents the sugar in two grams of the 
grain. 
The residue insoluble in water is stated as albuminoid matter insolu- 
ble in water, soluble in alcohol. In wheat this albuminoid matter con- 
sists of gluten and casein; in corn it has been stated as zein, although 
some investigators give it the name gluten-casein, and suppose it to be 
identical with the albuminoid matters similarly extracted from wheat. 
The sugar of wheat and corn seems to differ materially both from 
cane sugar and inverted sugar. On several occasions it separated in 
groups of prisms upon slow evaporation of its solution in 80 per cent. 
alcohol. Its taste is not particularly sweet, nor does it reduce Fehling’s 
solution, except slightly, until it has been inverted by dilute acids. 
ESTIMATION OF GUM.—The residual grain, after treatment with 80 
per cent. alcohol, is dried and then removed to a graduated cylinder, to 
which is added 200 c. c. of cold water. The mixture is frequently agi- 
tated during about four hours. One hundred e. ¢. are filtered by aid of 
the Bunsen pump, evaporated and weighed, ignited, and again weighed. 
ae Pee er, between these two weights equals the gum in one gram, 
ash-free. 
This gum extract in wheat usually contains a trace only of albuminoid 
matter, not sufficient to greatly vitiate the results. In ordinary maize 
the gum extract seems to be free from albuminoid substances. In 
sweet corn the extract here obtained is turbid and cannot be made 
clearer by repeated filtrations through fine paper. 
This turbid liquid gives the characteristic blue color of starch with 
solution of iodine. This color is permanent, if sufficient iodine has been 
used, and the blue starch iodide does not fall to the bottom, as is usual 
with ordinary starch. When the turbid aqueous liquid is evaporated a 
very large white residue remains; it differs very plainly from the gun 
residues obtained from ordinary maize, for they are very slight, and 
varnish-like in appearance. 
Millon’s reagent gives a somewhat questionable indication for albu- 
minoid matter. It seems, then, that sugar corn contains considerable 
starch in a modified soluble condition, and that the invariable turbidity 
of aqueous extracts of sugar corn is due to this soluble modification of 
starch rather than to the “presence of a trace of suspended fat (?),” as 
suggested by W. O. Atwater. (Am. J. Sci. and Arts, vol. 48, 1869, p. 
357.) The amount of this modified starch and gum was estimated by 
subtracting. from the water extract, in a sample of the whole grain, the 
sum of the sugar and albuminoids soluble in water. In this case all 
the albuminoids not removed by alcohol were considered soluble in 
water, although there is some doubt upon this point, which, it is hoped, 
