ON DEXTRINE AND DIASTASE. 
267 
fecula of the pulp. It is for this reason that M. Biot, believes 
that boiling roots for feeding cattle increases their power of 
nourishment, and renders them more digestible. 
MM. Biot and Persoz, in their memoir on the modifi- 
cation of fecula and gums by diluted acids, state that sul- 
phuric acid has the power to rupture the teguments of fecula, 
and liberate the dextrine, when fecula mixed with water is 
thrown into a boiling mixture of sulphuric acid and water, 
and the whole mixture then raised to 196° Fahr. They 
also say, that by boiling the rotatory power is much dimi- 
nished. When this solution is filtered and added to a large 
quantity of alcohol, a white floculent precipitate falls, which 
is dextrine. When pure dextrine is dissolved in water, and 
the solution filtered so as to obtain a perfectly limpid solu- 
tion, and then abandoned to itself, either with or without 
contact with the air, a white substance gradually precipitates, 
which has the appearance of inulin. It is not inulin, because, 
when dissolved in hot water, it turns the planes of polariza- 
tion to the right, whereas inulin turns it to the left. M. 
Biot considers this substance a modification of dextrine. 
In conclusion, M. Biot believed that the acid, by the aid 
of heat, first ruptured the teguments of the globules of fecula 
and sets the dextrine free, and then, if the heat was continued, 
acted on the dextrine, and converted it into sugar of amidon, 
without the acid communicating any of its substances to the 
product. 
In a letter addressed to the French Institute, 1st April, 
1833,* M. Guerin, announced his having obtained several in- 
teresting results with amidon, as follows: that tegumentary 
amidon has the same chemical composition as lignin, and that 
the soluble matter of M. Raspail was composed of two sub- 
stances, amidine and soluble amidin ; the first soluble in 
cold water, and the second insoluble in water, either hot or 
cold, but capable of being held in solution through the inter- 
vention of amidine. 
Anna], de Chem. et de Phys. tome lx, 1834. 
