ON THE VOLATILE OIL OP BETULA LENTA, ETC. 245 
is gradually dissolved ; the solution depositing crystals in all 
respects like those from the oil of Gaultheria. 
By passing a current of chlorine over the oil of Betula 
lenta it is rapidly absorbed, hydrochloric acid is evolved, 
and the oil gradually becomes a solid crystalline mass of a 
yellow color. If this be dissolved in boiling strong alco- 
hol the solution deposits it in brilliant four-sided plates, like 
the Gaultheria compound, which possesses the same proper- 
ties. 
Bromine combines with the oil, hydrobromic acid being 
evolved. 
By distilling the chlorine compound with iodide, cyanide, 
or sulphuret of potassium, compounds of the oil with iodine, 
cyanogen, and sulphur appear to be formed. The latter con- 
denses as a yellow oil, which by standing becomes crystal- 
lized, and has a very fetid odor. 
Ordinary nitric acid (1.40 sp. gr.) has little action on the oil 
when cold, but by heat a rapid evolution of red fumes 
occurs, and the oil is converted into a crystalline matter, 
having acid properties. It crystallizes in minute prisms, and 
combines with fixed bases to form salts, which fulminate by 
placing them on a hot surface. Fuming nitric acid acts un- 
assisted by heat. Both these products appear identical with 
the corresponding compounds of oil of Gaultheria. 
When oil of Betula lenta is mixed with concentrated 
sulphuric acid, but little change occurs, but if heat be applied, 
the oil is gradually dissolved, the mixture acquires a deep 
red color, and the odor of the oil ceases to be perceptible. 
If now it be allowed to stand, the solution becomes a mass 
of crystals, which after the removal of adhering sulphuric 
acid, have the properties of salicylic acid. By pressure 
between bibulous paper and crystalling from a hot solution 
in water the acid is obtained perfectly pure and white. Oil 
of Gaultheria yields salicylic acid under the same circum- 
stances. If the acid be in great excess, or too much heat be 
applied, the operation fails. It is probable that in this re- 
