770 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[March 23,1873. 
5th day. —11 c.c. iodine gave a faint violet; with 
17 c. c., a blue tinge, becoming more and more intense 
up to 25 c. c., but more of a lilac colour. Tannic acid : 
same reaction as on first day. 
6th day. —With iodine, a perceptible violet shade only 
after 20 c. c., but slightly deepened up to 25 c. c. A 
few drops of tannic acid caused a precipitate, which dis¬ 
appeared however on shaking; a permanent precipitate 
only after several drops. 
7th day. —22 c. c. iodine gave a violet tint, changing 
to red with 25 c. c., and becoming pure red with 30 c. c.; 
10 c. c. of tannic acid were required to cause opalescence, 
a slight precipitate separating after some time. 
8 th day. —A red tinge with 10 c. c. iodine, becoming 
gradually more distinct until perfectly red with 20 c. c. 
An excess of tannic acid causes opalescence. 
9 th day. —A red coloration with iodine; no precipitate 
with tannic acid. 
10/A day .—No coloration with iodine; a yellowish 
tinge with an excess. Also no reaction with tannic 
acid. The solution then remains one to two days in this 
state, after which sugar is formed, and may be easily 
detected by Fehling’s solution. After another week the 
sugar has disappeared, and the liquid is strongly acid. 
The author notes that decinormal iodine solution is per¬ 
fectly decolorized by exposure to the air for about six 
weeks; a millenormal solution in three to six days, and 
a decimillenormal solution on standing overnight. This 
is due, not to the evaporation of iodine only, but in 
great measure to the formation of hydriodic acid. 
The author’s interpretation of the above results is, 
that the solution obtained by treating starch with hot 
water passes through three stages of change when al¬ 
lowed to stand, until it is finally converted into glucose 
and other products. It is impossible to obtain a starch 
solution quite free from dextrin in the above manner, 
for perfectly fresh solution was never coloured blue by 
the addition of 6-10 c. c. decimillenormal iodine solution 
but always violet, the red colour of the iodized dextrin 
forming violet with the blue iodized starch; the first 
drop of tannic acid also gave a precipitate, which dis¬ 
appeared on shaking, because of the greater affinity of 
the tannic acid to dextrin than to starch, in consequence 
of which it does not combine with the latter till the 
whole of the dextrin is neutralized. 
A starch-solution allowed to stand about a week, during 
which time a fiocculont precipitate is deposited, yields a 
red colour with 10-20 c. c. of decimillenormal iodine 
solution, which colour corresponds to a dextrin obtained 
both by mashing and in the artificial preparation of 
dextrin. It is nearly always accompanied by a second 
dextrin, which forms a colourless compound with iodine. 
. Dextrin I. may moreover be readily detected in the pre¬ 
sence of much starch by operating with dilute iodine; 
no starch reaction is observed until the whole of the 
dextrin is saturated. With starch in the presence of 
much dextrin, no starch reaction is obtained, until a con¬ 
centrated iodine-solution is employed, so that both bodies 
may be readily detected when in the same solution. 
Tannic acid does not precipitate dextrin, and wdien 
starch is also present, the precipitate redissolves until the 
whole of the dextrin is fixed. 
If the starch-solution is allowed to stand more than a 
week in contact with air at a certain stage, the addition 
of decinormal iodine, drop by drop, causes a red streak, 
which, however, immediately disappears; the next day 
even this is perhaps not observed, and yet sugar is not 
to be detected in the solution, and in this case the addi¬ 
tion of an excess of iodine causes no coloration; in the 
first the reaction of dextrin I. is obtained. The body 
now present in the liquid the author terms dextrin II., 
dextrin passive to iodine, for which it has a greater affinity 
than dextrin I. He considers that it is also co-existent 
with dextrin I. in the fresh starch-solution, since 5-6 c. c. 
of the weak iodine may be added without causing the 
slightest coloration. 
Tayinic Acid in its action on Iodine , Starch, and Iodized 
Starch. —By the addition of an excess of tannic acid to an 
iodine-solution, the latter becomes gradually decolorized. 
Tannic acid also causes the decoloration of iodized starch- 
solution. In both cases the iodine is reduced to hy¬ 
driodic acid. In order to investigate the action of iodine 
on tannic acid, 60 grms. iodine, 60 grms. tannic acid, 
and about 800 c. c. water were digested in a stoppered 
flask on the water-bath, at a mean temperature of about. 
92°, the flask being repeatedly shaken. After some 
days the whole had dissolved to a dark brown liquid, 
from which over night a voluminous precipitate of gallic 
acid separated, but was redissolved on heating. After 
four to six days a permanent dark black crystalline pre¬ 
cipitate formed on the sides and bottom of the flask, te 
obtain a good yield of which the operation had to be 
continued for six to eight weeks. The black substance 
was purified by digestion with dilute ammonia, and. 
washing with water; a yellow body was thus obtained, 
which was dissolved in soda, re-precipitated by acid, and. 
then washed until free from sodium chloride. The com¬ 
position and reaction of this product proved it to be 
ellagic acid, C 14 H 6 0 8 + 2 aq., the yield being about one- 
fourth of the tannic acid employed. The filtrate from, 
the crystals, which deposited much gallic acid on stand¬ 
ing in the flask, was evaporated to a small bulk, and the 
remaining liquid decanted from the gallic acid which 
rad separated. In order to prove the presence of sugar 
and hydriodic acid, which it was probable were also pro¬ 
ducts of the reaction, an excess of a stiff starch paste was 
added to a portion, to remove free iodine, and the whole 
allowed to stand an hour or two, the supernatant liquid 
being then removed by a siphon. The addition of a 
crystal of potassium nitrite to this liquid at once pro¬ 
duced a deep blue coloration, proving the presence of 
hydriodic acid. In testing for sugar, the iodine, hy¬ 
driodic acid and gallic acid were removed by basic lead, 
acetate, the filtrate saturated with hydrogen sulphide,, 
evaporated somewhat, and finally Eehling’s solution, 
added, when, on warming, cuprous oxide was deposited. 
The products of the action of iodine on tannic acid are 
therefore ellagic, gallic, and hydriodic acids and sugar. 
Doubtless the tannin is first split up into gallic acid and. 
sugar, the gallic acid afterwards yielding ellagic acid, in 
proof of which the following experiment was made:— 
10 grms. gallic acid, 10 grms. iodine, and 160 c. c. water 
were digested together for several days on the water- 
bath; the same characteristic black crystals as above 
were obtained, and proved to be ellagic acid; after add¬ 
ing an excess of basic lead acetate to the filtrate, etc., no- 
sugar could be detected. The reaction is probably 
2 C 7 H 6 0 5 + I 2 = (C 14 H 6 0 8 + 2 HoO) + 2 HI. 
—Journal of the Chemical Society. 
FIRE AT MANCHESTER. 
On Sunday last a very disastrous fire occurred in Man¬ 
chester, on the premises of Messrs. Woolley and Sons, 
wholesale and retail druggists, 69, Market Street, by 
which damage was occasioned estimated at £20,000. 
The fire was discovered between four and five o’clock in 
the morning in the warehouse in Swan Court, and the 
fire brigade, were promptly in attendance. By the time 
of their arrival, the second or ground-floor of the ware¬ 
house, w’hich was extensively stocked, was in flames, that 
were rapidly communicating with the upper floors, and 
were also extending to the retail shop in Market Street. 
By seven o’clock the fire was so far subdued that the use 
of the steam fire-engine and a number of jets were dis¬ 
pensed with. The building and its contents were almost 
entirely destroyed, and several of the adjoining build¬ 
ings were damaged by water. The origin of the fire 
cannot be ascertained. Messrs. Woolley and Sons are. 
insured in the Lancashire and other offices. 
