PROCESS FOR PREPARING LINIMENTUM ACONITI. 
57 
Pharmacopoeia for the preparation of Emplast. Hydrarg., I think it desirable to 
acquaint my brother members of the Pharmaceutical Society with the result. 
On following strictly the directions, as well as the proportions given, I found 
that it was almost impossible to divide the mercury sufficiently by trituration 
with the oil and resin ; and on adding afterwards the litharge plaster, the mass, 
instead of having a tenacious consistence, was so crumbly as to prevent its being 
formed into the usual rolls. I had then recourse to the formula I have used for 
the last forty years, viz. substituting the same weight of Venice turpentine as the 
oil and resin combined, thus preserving the proportions of the mercury, and 
found it to answer completely ; the latter being much more easily divided, and 
the resulting plaster being of a good consistence. 
I am, Sir, yours very faithfully, 
Thomas Blunt. 
The Wyle Cop, Shrewsbury, July 4 th, 1864. 
ON THE PROCESS OP THE BRITISH PHARMACOPCEIA FOR PREPARING 
LINIMENTUM ACONITI, AND ON THE MEDICAL AGENCY OF THE 
LINIMENTUM SO PREPARED. 
BY M. DONOVAN, M.R.I.A., ETC. 
Many acrid vegetable substances, which are virulently poisonous in their natural 
state, are rendered innocuous by being dried by heat. Such is the case with many of 
the Aroidese and Ranunculacese. Aconite seems to be of the same character to a certain 
extent; and although the poison be not destroyed by drying, the noxious quality of 
the plant may be greatly weakened by being volatilized, or otherwise dissipated, or par¬ 
tially decomposed. 
The following statements have been made relative to aconite :—Bucholz, while occu¬ 
pied in making an analysis of the leaves of aconite, was seized with headache, pain in 
the back, and vertigo ; whence we conclude, says Berzelius, that the poison is volatile. 
Pereira, quoting Gieger, says that the emanations of the distilled water affect the eyes. 
Statements have been made to the effect that handling the fresh plant has produced 
tremblings and faintness ; and that in preparing the extract, the vapours have produced 
disagreeable symptoms, and enlargement of the pupils of the eyes, which has continued 
several hours. All these facts seem to point to the volatile and destructible nature of 
the acrid principle, and to the injury which the roots must sustain by being dried by 
heat. 
It became a question, therefore, whether the process adopted in the British Pharma¬ 
copoeia for preparing the linimentum aconiti is such as to preserve the properties of the 
roots of the plant without injury. 
Having procured a quantity of the root in a nearly dried state, I completed the 
drying by spreading it out on a well-regulated hot hearth, covered with sheets of paper. 
Of the dried root, twenty ounces were moistened with twelve ounces and a half of 
rectified spirit, and macerated for seven days. The whole was then percolated with the 
remaining seventeen ounces and a half of rectified spirit; eight ounces and a half were 
held absorbed by the powder permanently, and twenty-one ounces and a half of the 
liniment -were obtained, first cost in Dublin 7s. Gd. per pint of twenty ounces for mere 
materials, there being eight ounces and a half of liniment wasted in the residuum. 
The chief thing to be now ascertained was, whether the process of the Pharmacopoeia 
is injurious to the qualities of the aconite. The only way to ascertain this is by the 
application of the liniment on a sensitive part of the body, and by comparing its effects 
with those of another liniment similarly made with aconite roots recently taken from 
the ground, and neither dried nor heated. 
It being just the period of the year (late in May) when the roots are in best con¬ 
dition, I procured some fresh from the garden. They were sliced, immediately thrown 
into the proper quantity of rectified spirit, and allowed to macerate for twenty-four 
hours. 
