Many failures must be expected at first, from the salutary caution all good practitioners must observe in the doses of a remedy with which they are not practically familiar. On this point I have further to remark that in a case of traumatic tetanus, now under treatment, fifteen grain doses of the resin have been given every second or third hour, and of these doses five taken before narcotism was induced. In cases of tetanus, I consider no trial of the drug at all conclusive, unless it has been pushed to the extent of inducing stupor and insensibility. Too much importance has been attached by commentators on my paper to the occurrence of _catalepsy_ as an effect of this drug; catalepsy I have witnessed unequivocally in many cases, but the effect is not an universal one; I have seen it produced by ten drops of the tincture, and by one grain of the resin. But, on the other hand, I have given fifty grains in one day to a tetanic patient without any such effect being observable. It seems quite evident, from the experiments made by Mr. Ley and Dr. Pereira, that much larger doses must be used in this country than those we found sufficient in India. The cause of this is possibly to be traced to molecular chemical changes taking place by age in the constituents of the drug, and analogous to those familiar to the profession in the case of hemlock and its active principle. The tincture, made by dissolving the extract in spirit, I consider the best form of the drug for use in tetanic cases--or the resin may be made into an emulsion, by trituration with a little flour, carbonate of soda, and mucilage. The soda tends to dissolve the resin, and its use is in accordance with the precepts of the ancient Eastern writers, who prescribed hemp with alkaline substances, and used acids in various forms (such as oxymel and sorrel wine) to counteract its effects when taken in overdoses. In conclusion, I venture to refer to the very interesting cases lately published by Mr. Ley, in the Provincial Medical Journal. Another memoir from the same able pen, will, I understand, soon appear, and will afford ample evidence of the therapeutic value of this agent. Mr. Ley informs me that of the _anti-convulsive_ power of the hemp he entertains no doubt. This is the great, the valuable result to look for; all else is comparatively of but little importance. On some minor points Mr. Ley’s results differ from mine. This must be regarded but as a proof of the accuracy of his observations--that he is recording faithfully what he sees, and is not merely treading in the footsteps of another. I am, Gentlemen, Your faithful servant, W. B. O’SHAUGHNESSY, M.D. London, Feb. 8, 1843.