The total resins when placed on the end of the tongue produced a marked stinging sensation followed by a local anaesthesia. After the first stinging was produced the sensation was rather pleasant. The local anaesthesia persisted a long time, giving a sensation much the same as that produced by cocaine. The barium and iron acids also produced this local anaesthesia, but the initial stinging sensation was much more pronounced, which was probably due to the acid nature of the substance. _THE BARIUM ACID._ The resinous material used and spoken of as the “Barium Acid” is the material prepared and so named as given under the “Method of Separation”. PHYSICAL PROPERTIES:—Dark reddish brown in color, syrupy in consistency and has a characteristic odor; heavier than water; soluble in benzol, ether, alcohol and acetone, but insoluble in petroleum ether and water. This resin constitutes about sixty percent of the total ester resins; i.e. the resins left after the free acids have been removed with aqueous potassium hydroxide. An analysis of the barium salt obtained by precipitation from the potassium soap was made and the following data obtained:— Wt. of substance used 1.1715 .5860 Wt. of barium sulphate .4430 .2205 Barium equivalent .2606 .1298 Percent barium 22.2% 22.1% The following method was used in making the above analysis. The weighed material was ignited in a platinum crucible by gently heating until the combustible gases formed were given off. The crucible was then more strongly heated to completely burn off the carbonaceous material left. The residue was extracted with nitric acid and the barium precipitated as the sulphate with dilute sulphuric acid, and the weight of the barium sulphate determined. Expressed as the ACID NUMBER, or the number of milligrams of potassium hydroxide required to neutralize the free acids in one gram of the substance, the following data was obtained:— Barium equivalent .2606 .1298 Barium expressed as KOH equiv. .2131 .1062 Wt. of material used 1.1715 .5860 Milligrams of KOH per gram 181.9 181.3 ACID NUMBER 181.9 181.3 The following gives the ACID NUMBER obtained by direct titration of the barium acid; in “A”, barium hydroxide was used and in “B”, sodium hydroxide was used. A small quantity of the material was dissolved in a sufficient quantity of neutralized alcohol to give a liquid of a light yellow color, Phenolphthalein was used as the indicator, and the alkali was added until a red color was produced. “A” “B” Wt. of substance .6160 .2345 Cc. of alkalie 4.54 1.75 KOH equiv. per gram 41.40 41.90 Acid number 41.40 41.90