OBSERVATIONS ON MONARDIN. 87 
in some specimens of this oil, a crystalline deposit, analagous 
in appearance to camphor, and possessed of the taste and 
odour of the oil. As no notice has been taken of this fact in 
any of the works to which I have had access, the subject is 
possessed of sufficient interest to present, in the form of an es- 
say, a history of its sensible properties, and some of its che- 
mical characteristics. It evidently belongs to the camphor 
class, and may be the result of the absorption of oxygen. It 
is presented in two forms ; one in amorphous translucent masses 
with some slight evidences of lamination in the fracture ; the 
other in rhombic crystals closely aggregated together. The 
amorphous variety is white, has a conchoidal fracture, is very 
friable, and is reduced to powder with extreme readiness. Its 
amorphous condition appears to be due more to the manner in 
which it is deposited, than to any difference in its chemical 
character, as when fused, and gradually cooled, it assumes the 
crystalline form, and comports itself in the same manner with 
chemical reagents. This substance, which for the purpose of 
facilitating its description, may be called monardin, possesses 
the burning pungent taste, and peculiar odour of the oil of 
horsemint, and doubtless possesses the same medical properties. 
Monardin is very soluble in alcohol and ether, and is dissolved 
by the fixed and volatile oils, particularly oil of turpentine; 
hence the change of the oil of horsemint to the solid state, 
does not preclude its use in pharmaceutical preparations. It is 
very slightly soluble in water,communicating to|that fluid its odor 
and pungent taste. Monardin fuses at 118° Fahr. into a lim- 
pid oil, and when the heat is continued it commences boiling 
in a glass vessel at 418° Fahr., and at 438° its point of ebulli- 
tion is stationary. It boils readily and without discoloration, 
and may be distilled per se withrmt change, the vapour con- 
densing in a crystalline form if the receiver be kept cool. 
Fused monardin may be cooled down below 70° without solidi- 
fying, but if the smallest crystal of the substance be dropped 
in it, crystallization commences, and is propagated throughout 
in a few minutes. The usual crystalline form of monardin is 
