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ORIGINAL COMMUNICATIONS. 
liquid again evaporated, continuing the process, until it ceases 
to yield the insoluble matter. When finally evaporated to 
dryness, the residue is completely soluble in cold water. M. 
Biot found a solution of this substance to possess the rotatory 
power three times more powerfully than sugar. 
It renders cold water very mucilaginous, is insoluble in al- 
cohol and sulphuric ether: its aqueous solution becomes acid, 
after standing many days, and its transparence is troubled. 
Treated with nitric acid, it gives first oxalhydric, and after- 
wards oxalic acid. 
100 parts of amidine, and 250 parts of sulphuric acid, at 
about 150° Fahr. have yielded 95. S parts of anhydrous sugar. 
M. Guerin says that this substance differs much from the 
dextrine of Biot and Persoz, because, according to their me- 
moir, they assign as one of its chemical characters, fermenta- 
tion with yeast, which amidine does not. He prepared some 
of their dextrine, and found that it did ferment with yeast; 
but suspecting that it owed this property to sugar, he treated 
it with alcohol and found that it lost this property, and ac- 
quired that of coloring blue with iodine, instead of vinous red 
or purple. Thus deprived of sugar by alcohol, continues 
Guerin, it is yet composed of two substances, one soluble and 
the other insoluble in cold water. Biot and Persoz say, that 
their dextrine is the same as that made with boiling water 
alone, which corresponds with the declaration before mentioned 
of Payen and Persoz, that the substance obtained by diastase 
is composed of dextrine, sugar, and substance analogous to 
inulin. 
Tegumentary amidin, of Guerin, dried at 212° Fahr. 
has a light yellow color, neither odor, nor taste, without ac- 
tion on paper reactives, gives a beautiful blue color with 
iodine, is insoluble in water, either cold or boiling, alcohol, or 
sulphuric ether, and when left long in contact with water, 
swells, but is not altered. 
Soluble amidin, of Guerin, is the substance precipitated 
from the aqueous solution of amidon, in the process for pre- 
paring amidine; and according to that chemist, it is chemically 
