It is evident that the presence of another acid in the solution examined for hydrocyanic acid would render the detection of _cyanides_ impossible, but in all cases hydrocyanic acid can be separated without arriving at a decision in regard to its original state of combination. Nitric, hydrochloric, and several other acids would not be distilled at the temperature of the water-bath; an examination for these by the methods already described can therefore be instituted simultaneously with the search for hydrocyanic acid. DETECTION OF ALKALIES AND ALKALINE EARTHS. The separation of these bodies in the caustic state is a matter of difficulty owing to the great tendency they possess to become converted into carbonates; the carbonates of lime, baryta and strontia, moreover, being non-poisonous in their effects, will not be employed with criminal intent, and the carbonates of soda and potassa are extensively used as pharmaceutical preparations. Notwithstanding the small chances of success, the isolation of the compounds under consideration in the caustic state is to be attempted. To this intent, the organs to be analysed, together with their contents, are placed in a glass retort provided with a receiver, water added, and the mixture boiled. The distillate will contain the ammonia present. When, however, putrefaction has begun, the detection of this compound does not necessarily indicate its original presence in the suspected materials. If, after an hour's boiling, the fluid in the retort possess an alkaline reaction, it is to be examined for soda, potassa, strontia, baryta and lime. The undistilled solution is filtered, the filtrate evaporated to dryness, and the residual mass treated with alcohol. By this treatment, potassa and soda go in solution, lime, baryta and strontia[I]--as well as the alkaline carbonates--remaining undissolved. The potassa and soda are separated from the other salts present by filtering and evaporating the alcoholic solution to dryness and then calcining the residue in a silver crucible. The mass, which should still be alkaline, is then dissolved in dilute sulphuric acid. If the solution is turbid, traces of baryta or strontia may still be present and should be removed by filtration. Some hydrochloric acid and solution of bichloride of platinum are then added to a portion of the filtered liquid: in presence of _potassa_ a yellow precipitate is formed. [I] Baryta and strontia dissolve in alcohol, but only when they are anhydrous and the alcohol is absolute, which is not the case here.