ON THE MAGNOLIA GrRANDI FLORA. 
93 
coloring matter or of tanno-gelatin, has not been determined. 
It may be doubted whether tannin exists in this bark ; if it 
does, it must be in a modified form, as the usual reagents do 
not indicate it. This would seem to be corroborated by the 
statement elsewhere made, that tannin and gallic acid do not 
exist in the bark of the Magnolia glauca. 
Half a pound of the dried bark was macerated in alcohol 
(36° Baume) for six days, and the tincture decanted and fil- 
tered. This was suffered to evaporate spontaneously, when a 
semi-fluid mass, interspersed with numerous acicular crystals, 
was obtained. This matter was treated with a mixture of 
one part of solution of potassa (U. S. P.) to sixteen parts of 
water, until every thing soluble was removed, leaving a yel- 
low flocculent matter unaffected by the menstruum,which was 
collected on a filter. This substance was tenacious, adhesive, 
resembling soft putty, and had the taste of the bark in a con- 
centrated degree. By drying, it became dark colored. 
This substance was dissolved in alcohol, and water added 
to the alcoholic solution until it became slightly opalescent ; 
it was then allowed to evaporate spontaneously. Numerous 
acicular crystals were thus obtained, associated with a brown- 
ish matter, to be noticed hereafter. 
The crystalline matter possessed the following character- 
istics : It was insoluble in water, soluble in alcohol, cold, or 
hot, and in ether. It crystallizes in four sided acicular 
prisms, with obliquely truncated terminations ; they are 
very fragile, crack under the teeth, and when free from the 
brownish matter, have very little taste or odor. They melt 
at a low temperature, and when put in contact with flame in- 
stantly ignite and burn with a brilliant light, giving off much 
smoke and leaving a residue of carbonaceous matter. 
A small quantity of the crystalline matter was placed on 
the bulb of a thermometer, the greater portion of which 'was 
immersed in mercury, to which heat was applied. When 
the instrument indicated a temperature of 180° to 190° Fahr. 
the substance fused ; at 250° it began to volatilize ; and at 
270 to 300 it passed rapidly into vapor. About one-half was 
