A trade package of Waterbury's Metabolized Cod-Liver Oil Compound was purchased in the open market and examined in the Association laboratory. The product was a pale brownish-yellow, very slightly turbid liquid having an acid reaction and a malt-like odor. The odor was in no way suggestive of cod-liver oil or of cod-liver oil preparations. When strongly acidified with hydrochloric acid no precipitation or increase in turbidity was observable at once as would be the case were soaps present in appreciable amounts. On standing over night the acidified solution gave a flocculent precipitate. On shaking the acidified solution with ether-chloroform mixture and evaporating the solvent, a brownish, partially crystalline residue was obtained, the greater proportion of which appeared by qualitative tests to consist of salicylic acid. Ether-Chloroform-Soluble Matter: A portion was strongly acidified with hydrochloric acid and extracted with an ether-chloroform mixture. The solvent was washed with water, evaporated, the residue dried at 98 C. and weighed; 500 c.c. of the product gave 1.5222 gm. or 0.3044 gm. per 100 c.c. Attempts to separate the salicylic acid quantitatively from the fatty acids by crystallizing the former from hot water were not entirely successful. Free Fatty Acids—Salicylic Acid: The ether-chloroform-soluble residue was treated with hot water and filtered. The residue on the filter was dissolved in warm alcohol, the solvent evaporated to dryness, the residue treated with hot water to remove salicylic acid, and filtered. The undissolved residue on the filter was dissolved in warm alcohol, filtered and the filtrate evaporated to dryness, the residue dried and weighed as free fatty acid; 500 c.c. gave 0.0362 gm. in the first separation. The first crop of salicylic acid crystals, which separated from the hot water filtrate on cooling, was filtered out, the filtrate evaporated to small bulk and allowed to crystallize a second time. The first and second crops of salicylic acid were united, dried at 60 C., and weighed; 500 c.c. gave a total of 0.8421 gm. salicylic acid, or 0.1684 gm. per 100 c.c. A second yield of fatty acids was obtained from the filtrate from the salicylic acid separation by the process employed for the first, 0.0204 gm. being obtained. Total fatty acids isolated amounted to 0.0566 gm., or 0.011 gm. per 100 c.c. This residue gave the Pettenkoffer test for bile products thus indicating the probable presence in the preparation of traces of products derived from cod-liver oil. The filtrate, from which the fatty acids and salicylic acid had been separated so far as possible, was evaporated to dryness, the residue dried at 98 C. and weighed. A residue of 0.2505 gm. was obtained. This residue did not give Pettenkoffer's reaction for bile salts. It consisted of salicylic acid, free fatty acids and undetermined substances. Since 0.8421 gm. salicylic acid was separated from the residue or 55.3 per cent, of the total, it follows that not more than 0.6804 gm. or 44.7 per cent, of the initial residue can possibly be free fatty acids, or 0.13 per cent, as calculated on the entire sample. This value is evidently much too high as it includes everything in the initial residue not obtained as crystallized salicylic acid. It was noticed during the examination that whenever a fatty acid residue was dissolved in alcohol a noticeable residue remained which was also insoluble in water. Adding the several residues obtained, 0.8421 gm., 0.0566 gm. and 0.2595 gm., the sum of 1.1582 gm., is obtained. Subtracting the sum from 1.5222 gm., the initial residue, a loss of 0.3640 gm., is noted. As a check on the above the total acids were determined in a sample of 100 c.c. An ether-chloroform soluble residue of 0.330 gm. was obtained.