ON MI CEO-SUBLIMATION. 
415 
Picrotoxin. —Some difficulty is experienced in obtaining a sublimate from this 
substance. It bears a considerable amount of heat, and may be sublimed with¬ 
out powdered glass. The round granules are first produced, it being requisite 
to continue the heat five or six hours before a crystalline sublimate entirely 
takes their place. 
The alkaloids of opium yield crystalline sublimates which bear little resem¬ 
blance to one another. 
Morphine. —I believe that a crystalline sublimate of this substance was first 
obtained by Dr. Guy. It sublimes readily either with or without powdered 
glass, but a slight elevation of temperature causes it to change colour. Mor¬ 
phine seems to possess in a great degree the peculiarity of subliming in curved 
lines, it being almost impossible to obtain a sublimate which is wholly free 
from it. The sublimate crystallizes at all points of these curved lines, the 
predominating form being thin plates which polarize light. 
Narcotine. — Gmelin’s 1 Handbook ’ has the following,—“ When narcotine is 
heated a few degrees above its melting-point, it gradually acquires a deep red 
colour, and at about 220° C. froths up, evolves ammonia, and solidifies to an 
extremely porous mass consisting of a new base and acid.” I have not observed 
any change of colour during the sublimation of this substance, and infer from 
this that it had been sublimed under the temperature just mentioned. It sub¬ 
limes with some little difficulty in regular crystals. I have exposed narco tine 
to a heat sufficient to sublime it for three hours without observing the least 
trace of decomposition. 
Narceine is described by Dr. Pereira “ as fusing at 198°, and at a higher tem¬ 
perature decomposing.” It yields a crystalline sublimate with difficulty, the 
round granules are first produced ; with very careful manipulation these give 
place to needly crystals similar to those deposited from solution. 
Codeine is thus spoken of in Gmelin’s ‘ Chemistry,’•—“ Melted codeine, when 
more strongly heated, creeps up the sides of the vessel without volatilizing.” 
By the method I have described codeine may be easily sublimed in regular 
crystals. 
Papaverine sublimes when cautiously heated. I have exposed it to a heat 
sufficient to sublime it for nine hours, and the last sublimate has been as un¬ 
coloured as the first. The sublimate consists of perfect crystals, or when more 
rapidly sublimed of fan-shaped groups. 
Meconin is stated by Dr. Pereira to be capable of distillation. A sublimate 
is obtained with comparative ease, and without the least change of colour. It 
consists of perfect crystals, and, if too great heat has been used, of round gra¬ 
nules, which, on cooling, crystallize in tufts. 
Thebaine , according to Pereira, fuses at 198°, but does not volatilize at any 
temperature. According to Gmelin’s 1 Handbook,’ “ Thebaine yields, when 
heated, the ordinary decomposition products of nitrogenous substances without 
subliming.” I cannot understand how these two descriptions could have arisen, 
as thebaine yields a sublimate with as much ease as morphine or strychnine. 
When heated after melting it increases in colour; kept in this condition it 
sublimes readily. I have heated it for three hours with no decomposition, ob¬ 
taining three or four definite sublimates during that time. 
Piperin , when heated, melts at a comparatively low temperature, crystal¬ 
lizing again on cooling. It sublimes under favourable circumstances in perfect 
crystals. 
C'holesterin. —Heintz says, “ that when heated to about the boiling-point of 
mercury it sublimes, without alteration, in the form of light snow.” When 
heated, it melts and sublimes in crystals precisely similar to those deposited from 
solution ; a few perfect crystals are obtained, but the general sublimate is in 
large tabular pieces. 
