In the first table it will be noticed that if the data concerning the albumoses and peptones are omitted, the round and rump cuts in every case give higher figures than the other two cuts. When the hand-separated fat is eliminated we find less variation; the round and rump cut gives higher results than the rib but is equaled or slightly surpassed in a few cases by the loin. When the fat is entirely eliminated, as shown in the third table, the difference is still less. However, in only one case does the rib cut (steer 18, coagulable nitrogen) give as high results as the round and rump cut; and in another case (steer 503, amido-acid nitrogen) as high as the loin. In six cases the loin cut gives higher results than the round and rump cut. In general, steer No. 505 gives the highest results, especially in the case of the amido-acid nitrogen, there being only one exception, namely, the coagulable nitrogen in the rib cut on the fat-free basis. A further discussion of these results will not be attempted at this time. For the purpose of making an extended study of the composition of beef extract there was prepared at the Missouri station (at the time of slaughtering) a cold-water extract a from a 5-kilo sample of the round of each animal. The filtered extract was coagulated upon the water bath, filtered, and concentrated with one or two filtrations as the concentration proceeded. The extracts have been finally concentrated to a semisolid mass, in which condition they appear to remain in a state of perfect preservation. The life history of the animals from which these extracts have been prepared is known and during the next year cooperation in the examination of these extracts will be requested, to determine the composition of pure beef extract and to learn to what extent variation may be expected. The president announced the following membership for Committee B on recommendation of referees: Messrs. B. B. Ross, R. W. Thatcher, A. S. Mitchell, Paul Collins, and W. D. Bigelow. The following committee was appointed to wait upon the Secretary of Agriculture and the Assistant Secretary and invite them to address. the convention: Messrs. M. E. Jaffa, J. M. Bartlett, and W. A. Withers. On motion by Doctor Wiley, the vote on the amendments to the constitution was made special order for 12 o'clock, or following the presidential address, on Friday. REPORT ON PRESERVATIVES. By W. D. BIGELOW, Referee. SALICYLIC ACID. RAPID DETERMINATION OF SALICYLIC ACID. The methods of the association for the quantitative determination of salicylic acid are long and tedious because of repeated extraction with immiscible solvents. An attempt was made to simplify these methods by extracting a certain volume of the food, or an aqueous extract thereof, by means of a definite volume of solvent, evaporating to dryness an aliquot portion of the solvent used, and determining the salicylic acid in the residue. The total amount can then be calculated by a factor to be determined by experimental work. It is, of course, necessary that the solvent, under certain conditions to be adopted, should extract a uniform amount of salicylic acid uncontaminated by substances that a Trowbridge and Grindley, J. Amer. Chem. Soc., 1906, 28: 472. would interfere with the reaction by which the salicylic acid should finally be estimated in the residue. Owing to its rapidity and convenience, the ferric chlorid reaction has usually been employed for determining the amount of salicylic acid present. It is, therefore, important that the solvent employed should not extract tannin from the food. In order to determine what solvents should be most advantageously employed as far as delicacy of reaction and freedom from tannin or other interfering bodies is concerned, Mr. Charles S. Ash extracted 50 cc portions of claret containing salicylic acid in amounts varying from 0.025 mg to 0.5 mg and treated the residue obtained by evaporation of the solvent with ferric chlorid in the usual manner. The results are given in the following table: Comparative efficiency of solvents on salicylic acid dissolved in 50 cc of claret (Ash). 0.500 None. Good. Faint Good.. Good.. Good.. Good. Good.... Faint .250 .100 .050 Good. .025 Good. Good. Good.. Good. (?) Good.. Good. Trace? Good trace. Mr. Ash found that the first five solvents given in the table extract tannin in the order in which they are mentioned—that is, ether extracts the greatest amount and trichlor-acetylene the least. The last three solvents-carbon bisulphid, carbon tetrachlorid, and toluene-do not extract tannin, and the ferric chlorid reaction in the residue obtained by them from wine is clear and characteristic of ferric salicylate. It will be noted that the residue from the ether extraction gave no reaction whatever with ferric chlorid. This was due to the presence of tannin, which entirely obscured the reaction. With chloroform much better results were obtained, but even here the reaction was partially obscured by tannin, which was also true of the residue from dichlor-acetylene. The data given in the column headed "Ether and hydrogen peroxid" were determined by oxidizing with ammonia and hydrogen peroxid the residue obtained by evaporating the ether extract. This destroys the tannin and also partially converts benzoates and saccharin when present into salicylic acid. The salicylic acid was then again extracted with ether, the ether extract evaporated, and the residue tested with ferric chlorid. As previously stated, the greatest freedom from interfering substances attended the use of carbon tetrachlorid and toluene, the latter appearing to extract slightly more salicylic acid than the former, and thus affording a better test in the presence of a small amount of that substance. Chloroform was also very satisfactory, being inferior to carbon tetrachlorid and toluene in respect of dissolving interfering substances, though apparently slightly superior in the amount of salicylic acid extracted. 73673-Bull. 122-09- -5 Mgs. 100 50 Mgs. Mgs. Mgs. 8832 25 Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. Mgs. 63.2 63.4 60.8 60.6 61.6 60.2 60.0 60.2 60.0 49.4 49.6 50.4 51.0 49.6 30.6 30.6 30.6 30.6 31.6 32.4 29.8 30.4 24.8 24.2 24.6 14.6 14.6 15.2 14.8 15.2 15.8 14.8 14.6 11.8 12.0 13.6 49.2 30.8 24.4 25.4 24.6 14.8 13. 4 12. 4 12.4 10 Colorimet rically. By weight. By titra tion. 80.0 80.4 79.4 78.0 83.0 80.4 82.0 79.8 79.0 69.4 68.0 71.2 35.4 35.4 35.4 35.0 19.2 7.4 SHORT METHOD FOR THE QUANTITATIVE DETERMINATION OF SALICYLIC ACID. From the results of the qualitative test made by Mr. Ash it appeared that it would be advantageous to confine the work with the quantitative method to carbon tetrachlorid and toluene. Accordingly, Mr. Ash applied the method to various types of wine containing known amounts of salicylic acid varying from 2.5 to 100 mg per 100 cc. One hundred cubic centimeters of the wine were acidified with 5 cc of sulphuric acid (1 to 3) and 50 cc of the solvent were added, gently but thoroughly mixed, and the solvent separated after centrifuging; 25 cc of the solvent were transferred to a weighed watch glass by means of a pipette. With toluene the best results were obtained using a watch glass 4.5 inches in diameter and with carbon tetrachlorid one 4 inches in diameter. The solvent was allowed to evaporate spontaneously and the amount of residue determined by weighing. The residue was then dissolved in 5 cc of neutral alcohol and transferred into a small casserole, the watch glass being washed thoroughly with neutral boiling water and the salicylic acid titrated with one-hundredth normal barium hydroxid, 1 cc of the reagent being equal to 1.38 mg of salicylic acid. An aliquot part of the solvent was allowed to evaporate spontaneously, the residue dissolved in 2 or 3 ce of alcohol and diluted with water sufficiently for the colorimetric determination with ferric chlorid. When the amount of salicylic acid present in the original sample was not less than 25 mg per 100 cc, the results obtained by weighing and titration were far superior to those obtained by the colorimetric method, but with smaller amounts the last method was the only one applicable. No tannin was found in any of the residues and the ferric chlorid reactions were clear and entirely characteristic of pure salicylic acid. In the gravimetric and volumetric determination small amounts of soluble substances were extracted by the solvent. The weight of the residue from 25 cc of the solvent used in extracting normal wine varied from 2 to 3 mg and its acidity was equal to about 0.5 cc of one-hundredth normal barium hydroxid. The results obtained by Mr. Ash on different types of wine are given in the table. In each case these results are the average of three closely agreeing determinations. It will be noted that the results obtained by Mr. Ash with each solvent and with each type of wine are entirely consistent, and the results obtained by weighing and by titrating the residue agree closely with each other. For instance, by means of carbon tetrachlorid approximately 50 per cent of the salicylic acid present is extracted from dry, red, and white wines. The same reagent, however, extracted slightly more than 60 per cent of the salicylic acid present in the sherry, port, and angelica. Toluene, on the other hand, was found to extract about 70 per cent of the salicylic acid present in dry, white, and red wine and about 80 per cent of that present in sherry, port, and angelica. It would appear that this method might be used advantageously at least for a preliminary determination of the amount of salicylic acid present. The method was further examined by the referee and by P. B. Dunbar with a view to determining the reason for the varying results obtained with the different types of wine and so modifying the method that uniform results with all substances might be obtained. This investigation was confined entirely to carbon tetrachlorid because of the noninflammability of that substance. Known amounts of salicylic acid were dissolved in dilute alcohol, varying in concentration from 5 to 50 per cent by volume. One hundred cubic centimeters of these dilute solutions of alcohol, containing 1 mg of salicylic acid per cubic centimeter, were shaken in a separatory funnel with 50 cc of carbon tetrachlorid and the amount of salicylic acid determined in 25 cc of the solvent. The figure so obtained was multiplied by two for the purpose of determining the percentage of the salicylic acid extracted in the total amount of solvent employed. The following results were obtained: It will be noted that the percentage of salicylic acid recovered under these conditions increases with the alcoholic content of the solution up to 25 per cent and then decreases, the maximum results being obtained with from 25 to 30 per cent of alcohol. California red wines, dry and sweet, were then treated in the same manner. Their alcoholic content was increased to 25 per cent and salicylic acid was dissolved in them to the extent of 1 mg per cubic centimeter. Several determinations of salicylic acid were then made by the method described and in each instance 61.2 per cent of the amount of salicylic acid added was recovered. The method was also applied to 100 cc of a solution containing 10 grams of sugar and 25 per cent of alcohol by volume. The amount of salicylic acid recovered from this solution was practically identical with that recovered from a 25 per cent solution of alcohol. Blanks were also run by extracting with carbon tetrachlorid 20, 30, 40, and 50 per cent alcohol acidified with 5 cc of sulphuric acid (1 to 3). It was found that no sulphuric acid was extracted and it was therefore unnecessary to wash the carbon tetrachlorid solution with water after extraction. DETERMINATION OF SALICYLIC ACID IN DARK BEER AND OTHER CARAMELIZED Attention has frequently been called to the possibility of error in the determination of salicylic acid in malt extract and beer prepared from highly colored malt and in highly caramelized substances, such as certain varieties of breakfast food. This a J. Brand, Zts. gesam. Brauw., 1893, 16: 303; H. Kiliani and M. Bazlen, Berichte, 1894, 27 (3): 3115-20; Amer. Brewer's Rev., 1907, 21 (5): 222; Western Brewer 1907, 32 (8): 456. matter was independently studied by A. M. Doyle and P. B. Dunbar, of the Bureau of Chemistry. Both reported that the color given by ferric chlorid with the material extracted from highly colored malt by ether was quite different from the salicylic acid and one should not be mistaken for the other, although the presence of a small amount of salicylic acid may readily be masked by the material extracted from highly colored malt and similar material. Experiments on malt-nutrine alone and on malt-nutrine containing salicylic acid (100 mg per liter) indicate that there is some possibility of being deceived by the color when ferric chlorid is added directly to the dish containing the dried residue obtained by evaporating the ether solution. In this case a color is sometimes developed which slightly resembles the salicylic acid reaction. If this color is examined in a good light and compared with the color developed by salicylic acid and ferric chlorid there is little danger of being deceived. It is better, however, to carry the evaporation of the extract to about 5 cc on the steam bath and then to complete the evaporation by means of a blast of air, since heating to dryness may darken the residue. The dry residue should be dissolved in a little hot water and ferric chlorid added to this solution. Under these conditions it seems impossible to mistake the salicylic acid reaction. Millon's reagent, freshly prepared, which has been suggested for the detection of salicylic acid in such substances, was not found by either Miss Doyle or Mr. Dunbar to be as satisfactory as ferric chlorid. In the absence of salicylic acid this reagent gives a light pink color, whereas in its presence a deep red is given. The intensity of the color seems to vary so much with the time of boiling, however, as to render the reaction uncertain and unsatisfactory. Both methods were also applied to highly caramelized breakfast foods, to which these observations also apply. DETERMINATION OF BENZOIC ACID. Several methods for the quantitative determination of benzoic acid have been suggested recently. Among these the following have been studied by the referee and his collaborators: (1) La Wall's method; (2) La Wall's method modified by mixing a definite weight of tomato ketchup with sufficient saturated sodium chlorid solution to make a definite volume, filtering, and extracting an aliquot portion of the filtrate with chloroform; (3) precipitation as copper benzoate; (4) precipitation as silver benzoate; (5) distillation with steam after decomposing organic matter with sulphuric acid and extracting with ether. It will be noted that the first four methods depend on extracting the benzoic acid from the food or an aliquot extract of the food by means of an immiscible solvent, whereas the fifth depends on separating the preservative from the food by distilling with steam. Before applying the first four methods a preliminary study was made of the relative advantages of several solvents. This question has been greatly altered by the introduction of the principle of "salting out" the benzoic acid by means of a saturated solution of sodium chlorid. The benzoic acid is thus rendered much less soluble in the solution from which it is extracted and consequently much more readily extracted by the immiscible solvent. The relation of the immiscible solvent to the preservative thus more nearly coincides with the direct solubility of the former in the latter. An approximate determination was therefore made of benzoic acid in several solvents. It was found that the solvents more commonly employed dissolved benzoic acid as follows, 100 cc of the solvent being used in each case: Ether, 25.70 grams; chloroform, 17.34 grams; carbon tetrachlorid, 7.65 grams; toluene, 7.58 grams; benzol, 6.40 grams. The chief desiderata in the extraction of a substance of this kind are, first, completeness of extraction; second, freedom of the extract from interfering substances; and third, noninflammability. Of the four solvents mentioned, it would appear from the solubility that by far the most complete extraction can be obtained by means of ether, and this is known to be true. Ether is objectionable, however, because of its property of dissolving water and its consequent tendency to extract tannin, salts, min |