A difficulty is usually met with in making the lactu-carium preparations, occasioned by the caoutchouc principle always present in this as well as most, if not all, the products from the lactescent plants; in order to overcome this difficulty, petroleum benzine has been found the most practical, being efficient and cheaper than most of the solvents for caoutchouc. It was found that by beating the lac-tucarium in an iron mortar until it is well crushed, it separates into layers, or plates, or very coarse granulation (according to its degree of dryness), as the nearest possible approach to comminution, it being impossible to powder it without the addition of sand or other foreign substance. Thus treated and macerated with benzine, the caoutchouc principle is readily dissolved, and the lactucarium is fitted for treatment with other menstruum. After numerous experiments, the following is offered as a practical working formula for the fluid extract: - Take lactucarium, 16 troy oz.; deodorized petroleum benzine, 32 fl. oz.; a sufficient quantity of diluted alcohol.

Beat the lactucarium thoroughly in an iron mortar; introduce it into a wide-mouth bottle of about 3 pints capacity, adding the benzine, corking tight, and allowing it to macerate, with frequent agitation, for 24 hours; let it rest about 24 hours, or until the lactucarium subsides, and the benzine solution becomes clear or nearly so; having decanted the benzine solution, transfer the lactucarium to a stone or glass slab or other similar vessel, spreading it as thin as possible, allowing it to remain in this situation until completely dry (at least 24 hours); rub it up in an iron mortar with an equal bulk of clean sand; introduce it into a cylindrical percolator, first prepared with a disc of flannel and a thin layer of sand, pack lightly, and add sufficient diluted alcohol to cover several inches, and after closing the outlet with a cork or otherwise, allow it to macerate 24 hours; percolate to exhaustion, reserving the first 4 fl. oz. By means of a still, reclaim the alcohol, and evaporate the residue in a water bath to 10 fl. oz., mixing this with the reserved percolate, and filter, adding sufficient diluted alcohol to wash the filter and remaining residue, until the product weighs 16 troy oz. (Lemberger).