At a late sitting of the _Paris Academy of Medicine_, M. ORFILA, the celebrated toxicologist, read a paper on _Nicotine_--the poison used in the Bocarme murder. It is the essential principle of tobacco. Virginia tobacco yields the largest proportion of _nicotine_; from twenty pounds, were extracted four hundred _grammes_ of the poison; a gramme is equal to 15·444 grains troy. The Maryland leaf affords about a third of that quantity. Nicotine is nearly as powerful and rapid as prussic acid with the animal economy. Five or six drops applied to the tongue of a dog, killed in ten minutes. The progress which medical jurisconsults have made recently, is so great, that poisoning by morphine, strychnine, prussic acid, and other vegetable substances, hitherto regarded as inaccessible to our means of investigation, may now be detected and recognized in the most incontestable manner. M. Ortila, in closing his notice, says: "After these results of judicial medical investigation, the public need be under no apprehension. No doubt intelligent and clever criminals, with a view to thwart the surgeons, will sometimes have recourse to very active poisons little known by the mass, and difficult of detection, but science is on the alert, and soon overcomes all difficulty; penetrating into the utmost depths of our organs, it brings out the proof of the crime, and furnishes one of the greatest pieces of evidence against the guilty." * * * * * In the LONDON ROYAL INSTITUTION, May 23, M. Ebelman, of the Sèvres works, near Paris, being present with various specimens of the minerals which he has produced artificially,--Mr. Faraday stated the process and results generally. The process consists in employing a solvent, which shall first dissolve the mineral or its constituents; and shall further, either on its removal or on a diminution of its dissolving powers, permit the mineral to aggregate in a crystaline condition. Such solvents are boracic acid, borax, phosphate of soda, phosphoric acid, &c.:--the one chiefly employed by M. Ebelman is boracic acid. By putting together certain proportions of alumina and magnesia, with a little oxide of crome or other coloring matter, and fused boracic acid into a fit vessel, and inclosing that in another, so that the whole could be exposed to the high heat of a porcelain or other furnace, the materials became dissolved in the boracic acid; and then as the heat was continued the boracic acid evaporated, and the fixed materials were found combined and crystallized, and presenting new specimens of spinel. In this way crystals having the same form, hardness, color, specific gravity, composition, and effect on light as the true ruby, the cymophane, and other mineral bodies were prepared, and were in fact identical with them. Chromates were made, the emerald and corundum crystalized, the peridot formed, and many combinations as yet unknown to mineralogists produced.