All wools contain a certain amount of animal oil or grease, which permeates every portion of the fleece. The proportion of oil varies with the breed of sheep. A difference in climate and soil materially affects the yield of oil. This is shown by analyses made of different kinds of wool, both foreign and domestic. Spanish wool was found to have but eight per cent. grease; Australian wool fifteen per cent.; while in some fleeces of Pennsylvania wool as high as forty per cent. was obtained. To extract the oil from the wool, a fleece was put in a tall cylinder and naphtha poured on it. The naphtha on being allowed to drain through slowly dissolved out the grease. This naphtha solution was distilled; the naphtha passing off while grease remained--a dark oil having high specific gravity and remaining nearly solid at the ordinary temperature. I am indebted to Mrs. Richards for this method of extracting the oil. The process is quick and inexpensive, and is applicable to the treatment of large quantities of wool. The object of these experiments was to find the readiest method of separating wool oil into its bases and acids, and further to identify the various fatty acids. A solution of the oil in naphtha was cooled to 15 deg. C. This caused a separation of the oil into two portions: a white solid fat and a fluid dark oil. The first on examination proved to be a mixture of palmitic and stearic acids existing uncombined in the wool oil. The original wool oil was saponified by boiling with alcoholic potash. The soap formed was separated into two portions by shaking with ether and water. On standing, the solution separated into two layers, the upper or murial solution containing the bases, the lower or aqueous solution containing the acids. This method of separation is very slow. In one case it worked very well, but as a rule appeared to be almost impracticable. Benzol and naphtha were tried, instead of ether, but the results were less satisfactory. On suggestion of Prof. Ordway, potassium chloride was added to the soap solution partially separated by ether and water. This caused an immediate and complete separation. By the use of potassium chloride it was found possible to effect a separation with benzol and water, also with naphtha and water.