158 
ON HYDROC H LORATE OF MORPHIA. 
fiibre remain in union with the sand and constitute the ulti- 
mate marc. The solution contains the bimeconaie, and a mi- 
nute portion of sulphate of morphia, which is more or less 
present in every specimen of good opium. 
2. The next step of the process is the separation of the mor- 
phia in the solution, and its conversion into the hydrochlo- 
rate ; to effect which the following means have answered bet- 
ter than any other which I have employed. 
a. The solution is first concentrated to the consistence of a 
thin syrup, and then precipitated by the diacetate of lead, 
which decomposing the bimeconate and the sulphate of mor- 
phia, forms an insoluble meconate and a sulphate of lead, and 
a soluble acetate of morphia. As the precipitate falls slowly, 
owing to the viscid nature of the solution, distilled water, 
equal to twice the bulk of the solution, is added to it, and the 
whole left at rest for twenty-four hours. 
On decanting the supernatant fluid, the precipitate is to be 
well washed with tepid distilled water ; the washings added 
to the solution of the acetate of morphia, and the whole evapo- 
rated to one^half. 
b. The diacetate of lead is used in this step of the process 
instead of the chloride, because it throws down the whole of 
the gummy matter with which much of the brown acid ex- 
tractive is combined; and thus frees the operation from two 
of the most troublesome substances which interfere with the 
purification of the hydrochlorate. It is obvious, however, 
that some acetate of lead may remain in the solution; to free 
it from which, diluted sulphuric acid is added to it, in slight 
excess; an insoluble sulphate of lead, if any of the acetate be 
present, is thrown down, and the acetate is converted into the 
sulphate of morphia. The supernatant fluid is next decanted, 
the precipitate washed with tepid distilled water, and the 
washings being added to the solution, the whole is to be boiled 
for some minutes to drive off the acetic acid which has 
been set free. 
The last step of this stage of the process is the conver- 
fion of the sulphate into the hydrochlorate of morphia ; a 
