316 
REMARKS ON SENNA. 
number of tbe Society’s Journal. The subject is important and interesting in 
itself, and the novelty of the facts stated, and the information yielded as to the 
real nature of the cathartic principle of the drug, must draw the attention of 
pharmaceutists and medical men to its value. The interest of the paper was 
enhanced considerably to us, by the fact that we had spent much time in en¬ 
deavouring to isolate the purgative principle, and obtain it in a form capable of 
producing all the beneficial physiological action of the infusion, unaccompanied 
with the feelings of sickening and loathing experienced by almost every one at 
the very thought of the drug. Whatever interest to ourselves our own labours 
in connection with senna ma_y possess, we would not have thought of making 
them public, but for the belief that they may be of some value to others, if 
only by confirming, in the main, the results arrived at by the author of the 
paper in the Society’s Journal, and those gentlemen whose works he quotes. 
We claim nothing that can in the least lessen the merit of these chemists, and 
the honour due to them for what they have so ably done. 
It is now nearly thirty years since our investigations led us so far as to find that 
the principle of senna, upon which its cathartic action depends, could form a solid 
compound, which, in the dose of 4 or 5 grains, possessed all the beneficial ac¬ 
tion of a full dose of senna infusion. The method adopted by us to obtain the 
compound in question, was this :—The watery infusion of senna was concen¬ 
trated in a good vacuum to not too thick a syrup. The extract was then wrought 
up with abundance of rectified spirit, which caused a separation of the gummy 
and other inert matters in a solid form, and, if the concentration had not been 
carried too far nor the spirit too strong, the active material was entirely con¬ 
tained in the spirituous liquid. It was found to be of the utmost importance 
that the spirit should not be above a certain strength, for if attention to this 
point was neglected, a portion of the active principle (more or less, according 
to the strength of the spirit) was found in the solid matter separated. There 
is, however, a sure rule for knowing when the spirit is too strong or the extract 
too thick, and it depends on the circumstance that when an aqueous extract of 
senna is mixed up with too strong spirit, the separation produced by the action 
of the spirit forms clotty masses, instead of a more or less loose solid. When 
the separation forms clotty masses, the remedy is to pour off the spirit and mix 
in as much water, with the clots, as will completely disintegrate them. The 
resulting solution, or syrupy liquid, is again treated with the rectified spirit be¬ 
fore used, and as much more as may be necessary. By this means a spirituous 
solution is obtained containing the whole of the cathartic principle of the 
senna. 
The liquid thus prepared gave us the means of obtaining the compound above 
referred to, which is composed of a mixture of acids and other substances com¬ 
bined with lime, and free lime. So far as it could be tested by its action on the 
human frame, it contained all the active principle of the quantity of senna from 
which it was obtained. To prepare it, slacked lime was made into a milk and 
added to the spirituous solution of the extract of senna above mentioned, and 
the resulting precipitate on being collected by filtration, washed with strong 
spirit, and dried as much as possible by strong pressure between folds of blotting- 
paper, was found, as already mentioned, to be a powerful cathartic in the dose 
of 4 or 5 grains. 
The denial of the solubility of the active principle of senna in strong spirit, 
made by Mr. Groves, is in part correct, but cannot apply to the tincture of 
senna of the British Pharmacopoeia, as the spirituous solutiou which gave us 
the cathartic compound was, at the least, above proof, and was found by our¬ 
selves in experiments on our own persons, to have the full strength of its equi¬ 
valent of senna leaves. 
After reaching the length we have indicated in our researches, we were re- 
