arises. This size appears ample, and might shorten the time used to expel the air. A 50 cc. funnel was used, as the 100 cc. appeared unnecessary and top heavy. It was found essential to add additional hydrochloric acid after the charge of extract, 10-15 cc. being added. Rubber gloves were also found to be very useful.

R. Hoagland. The results obtained by calculating the percentage of nitrate from the volume of nitric acid at 0°C., 760 mm., are incorrect, since measured quantities of a standard solution of sodium nitrate yielded only from 80-92% of the theoretical quantity of nitric oxid. When a portion of the standard solution of nitrate was run into the reaction flask after a sample of meat extract, the quantity of nitric oxid liberated was always smaller than that obtained from a like volume of the standard solution run before the meat extract.

DISCUSSION OF RESULTS.

The results of the first five analysts show an average recovery of 82.6 per cent of the added sodium nitrate when compared with the amount of gas obtained from a standard nitrate solution. Two of the analysts. show 69.4 per cent average recovery when calculated from nitric oxid at 0°C. and 760 mm.

The only explanation the associate referee can offer for the wide variation in the results obtained by the last analyst is that either all the air had not been driven from the flask before the extract was added or the apparatus was not air tight. From 0.1 to 0.19 per cent of sodium nitrate is reported in Sample A which was prepared from fresh (not cured) meat, and a negative qualitative test for nitrates is shown.

The following modifications are suggested for future work on this method:

APPARATUS.

(1) That a 40% solution of commercial sodium hydroxid be substituted for the water used in the trough so that the carbon dioxid may be effectively absorbed.

(2) That just after "into a trough containing water", the following be inserted, "The lower end of this delivery tube, should be slightly constricted."

(3) That beginning with "midway on the delivery tube, etc.", to end of paragraph, be deleted.

DETERMINATION.

*** is equivalent to

(1) That "Calculate the volume of nitric oxid at 0°C. and 760 mm. 0.0037935 gram of sodium nitrate” be deleted. Comparing the volume of nitric oxid found with the volume obtained from a known weight of pure sodium nitrate serves as a check upon the method, and the results reported indicate that this method gives a more accurate basis for calculation.

(2) That at the end of the method the following be added: "This is conveniently done by transferring the measuring tube to a tall jar containing a 40% sodium hydroxid solution (commercial). The temperature of the surrounding caustic solution will soon (10-15 minutes) be imparted to the contents of the tube, and the volume of nitric oxid is read with the tube in such a position that the level of the solution within and without the tube coincides. The caustic solution in the jar should be kept at room temperature".

Hoagland suggested a convenient device for cooling the soda solution in the trough during the determination which greatly facilitates the operation. It consists of fitting a single coil of tin tubing into the trough and passing a current of cold water through it during the determination. It would be advisable to add the following suggestion of Hoagland as an explanatory footnote on the manipulation of the method:

After all of the air has apparently been driven out of the apparatus, boil a short time longer after the delivery tube has been placed under the eudiometer to make certain that no air remains. Gradually introduce a measured portion of standard nitrate solution, rinse the funnel tube with 10% hydrochloric acid, and boil until all of the nitric oxid has been driven over. After the gas tube has been removed, quickly invert another tube over the delivery tube and boil a short time longer to make sure that all of the nitric oxid has been driven over. Run another portion of the standard solution into the apparatus, and repeat the determination. Then run the samples in the same way, in each case making certain that all of the nitric oxid has been driven over. After running 6-8 determinations, not counting the standards, finally run another standard. The three standards should check within 0.5 cc. on about 35 cc.

RECOMMENDATIONS.

It is recommended

(1) That further work be done on this method, using beef extract, meat and other meat products.

(2) That the following 1916 recommendation be studied during the coming year: That the referee for next year attempt to determine the relative amounts of some of the dissociation products in water-soluble and water-insoluble meat proteins.

(3) That the title of the method be changed from "Nitrates" to "Nitrates and Nitrites (calculated as sodium nitrate)".

No report on meat extracts was made by the associate referee for the year ending November, 1918.

REPORT ON MEAT EXTRACTS.

By C. R. MOULTON (Agricultural Experiment Station, Columbia, Mo.), Associate Referee1.

Nothing definite has been accomplished during 1919.

It is recommended

(1) That an attempt be made to determine the relative amounts of some of the dissociation products in water-soluble and water-insoluble meat proteins. This probably can best be accomplished by studying certain groups of amino acids, or other protein derivatives, in meat and meat extracts, in collaboration with other referees to be appointed by the association.

1 Associate referee for the year ending November, 1919.

(2) That the work on the separation of some of the amino acids. derived from meat proteins be continued.

(3) That the associate referee be not bound to a single method, but be left to choose as circumstances dictate and the collaborators accept.

REPORT ON EGGS AND EGG PRODUCTS1.

By C. E. MARSH (State Department of Health, Boston, Mass.), Referee. The work of the last two years consisted of the following:

(1) Testing methods for the determination of decomposition in eggs. This included a comparison of the Folin and the Hendrickson and Swan method for the determination of ammoniacal nitrogen3, and the comparison of the United States Department of Agriculture method for the determination of dextrose with that of Klein.

(2) Analyses showing the composition of both fresh and decomposed eggs.

(3) Methods for the detection of decomposition in dried eggs.

(4) Methods for the determination of heavy metals in dried eggs. Later, it was suggested by R. W. Hilts (U. S. Food and Drug Inspection District, U. S. Appraiser's Stores, San Francisco, Calif.) that work be done on Juckenack's method on lecithin-phosphoric acid' with a view to reaching a suitable official method. This suggestion was adopted, and the following methods sent out to the collaborators:

FOLIN METHOD FOR AMMONIA3.

Weigh about 20 grams of the well-mixed sample into a cylinder, add 5 cc. of saturated sodium carbonate, 2 cc. of a saturated solution of potassium oxalate, and some mineral oil to prevent frothing. Close the cylinder with a stopper containing two tubes, one of which reaches to the bottom of the cylinder, the other being of the distillation bulb and trap type to prevent any liquid passing over. The lower end of the second tube should pass into a 100 cc. flask containing about 50 cc. of water and 2 cc. of N/10 acid. If the outlet tube from the cylinder is slightly larger than the inlet, frothing will be reduced. Now blow a current of air (freed from ammonia by being passed through a sulphuric acid bottle) through the eggs, any ammonia carried over being absorbed by the acid. About 2 hours is usually required for this part of the process, but the exact time should be determined by experimentation in each laboratory. The cylinders found most convenient by the Massachusetts State Department of Health are 111 inches tall and inch in diameter, inside measure.

After the complete distillation of the ammonia, dilute 5 cc. of Nessler's solution with 25 cc. of water. Add this in three portions to the distillate, and dilute with water to 100 cc. Compare the colored solution, in a Duboscq colorimeter, with that produced

1 Presented by H. C. Lythgoe.

J. Biol. Chem. 1912, 11: 493.

'J. Ind. Eng. Chem., 1918, 10: 614.

Z. Nahr. Genussm., 1900, 3: 13.

J. Biol. Chem., 1912, 11: 493.

from a known amount of ammonium sulphate (usually 1 mg. per 100 cc.) treated in the same way with the Nessler reagent, and calculated as mg. per 100 grams. The standard ammonium sulphate is conveniently made of such strength that 5 cc. contain 1 mg. of nitrogen.

Preparation of the standard.-As ordinary C. P. ammonium chlorid contains pyridin and other bodies which interfere with the reaction of the Nessler solution, it is necessary to treat some of it with sodium carbonate in an apparatus similar to that described on page 507, and blow into C. P. dilute sulphuric acid until it is neutralized. Precipitate the ammonium sulphate with an equal volume of alcohol, filter, and dry. To obtain a standard solution of which 5 cc. contains 0.001 gram nitrogen, 0.471 of the purified product should be dissolved in sufficient water to make 500 cc. of solution. When a blank is distilled with this standard, at least 95% of the ammonia should be recovered; with ordinary C. P. ammonium chlorid only about 80% can be recovered.

HENDRICKSON AND SWAN METHOD FOR THE DETERMINATION OF AMMONIACAL

NITROGEN1.

Weigh 25 grams of the well-mixed sample into a tared dish, and pour into the aeration cylinder, transferring the egg adhering to the sides of the weighing vessel with the aid of four successive 25 cc. portions of ammonia-free water. Add 75 cc. of alcohol, mix, and let stand for 15 minutes. Then add 10 grams of sodium fluorid, 2 cc. of 50% potassium carbonate, and 1 cc. of kerosene. Connect the apparatus, and aerate strongly until no more ammonia comes over, then titrate at once with N sodium hydroxid. The apparatus used is essentially that of Folin, except that an aeration cylinder 50 mm. in diameter and 350 mm. high is used. Ordinary glass tubing sealed at the bottom and with small holes punctured according to the method of Folin and Farmer is used in place of the special ammonia absorption tubes. It is recommended that a blank containing 1 mg. of nitrogen be run at the same time as the sample.

UNITED STATES DEPARTMENT OF AGRICULTURE METHOD FOR DEXTROSE IN EGGS3. After thoroughly mixing the sample, weigh 25 grams into a 100 cc. lipped beaker. Wash the sample into a 200 cc. graduated flask, using 70 cc. of distilled water. (Add about 40 cc. first, and mix the sample with the water by stirring with a rubber-tipped glass rod. After the contents of the beaker have been poured into a graduated flask, use a 20 cc. and finally a 10 cc. portion of distilled water to thoroughly wash the beaker.) Then add 2 cc. of 5% acetic acid to the sample if it be egg white, or 1 cc. of the acid if the sample is mixed egg or egg yolk; mix thoroughly by shaking the flask, and place the flask in a water bath at 100°C. Egg should coagulate in 10 minutes. (There is danger of foaming during the first 5 minutes of heating.) After the egg material has been coagulated, place the flask in cold water until the contents are of room temperature. Then make up to the mark with alumina cream that has been washed several times to take out the dissolved salts. Shake the sample vigorously for 1 minute, allow it to stand about 5 minutes, and then shake for 1 minute.

The egg material should then filter readily, especially if folded filters are used. The filtrate is clear and nearly colorless, and the reducing sugars determined in an aliquot should be calculated as dextrose.

Fresh egg white yields about 0.44% of dextrose;

Fresh egg yolk yields about 0.22% of dextrose; and

Fresh mixed egg yields about 0.34% of dextrose.

1 J. Ind. Eng. Chem., 1918, 10: 614.

2 J. Biol. Chem., 1912, 11: 493.

Personal communication from U. S. Food and Drug Inspection Station, U. S. Appraiser's Stores, Boston, Mass.

The results were obtained from composite samples, and variations of as much as 0.03 per cent seldom occur. As the egg material deteriorates, the dextrose content decreases. If the liquid egg has an excess of white or of yolk, the dextrose content can readily be calculated if a moisture or a fat determination is made.

KLEIN'S MODIFICATION OF THE BENEDICT AND LEWIS METHOD FOR THE DETERMINATION OF DEXTROSE IN EGGS1.

ESTIMATION OF REDUCING SUBSTANCES IN FROZEN AND FRESH EGGS.

Weigh out 5 grams of eggs and wash into a 100 cc. sugar flask with about 25 cc. of water and fill up to the mark with a saturated aqueous picric acid solution. Shake the mixture thoroughly and allow it to stand for about 10 minutes. Filter the clear, yellow, supernatant liquid through a dry, double-folded filter paper. Introduce 10 cc. of the filtrate into a 50 cc. volumetric flask to which 3 cc. of saturated picric acid, 2 cc. of sodium carbonate solution (10 grams of anhydrous sodium carbonate to 100 cc. of water), and a few glass beads are added. Heat the flask on a sand bath until the solution is evaporated nearly to dryness. Care must be taken not to char the organic matter. A color will develop, varying in shade from yellow to dark red, depending on the amount of reducing matter present. Wash the neck and the sides of the flask with a few cc. of hot water, and boil the solution for about 3 minutes. Add warm water to dissolve the evaporated mass. Cool the flask to room temperature, and make up the contents to volume. If the solution is turbid, filter it through a cotton plug, rejecting the first few cc. of the filtrate.

Introduce the clear liquid into a Duboscq colorimeter chamber, and compare with a standard. The standards are made up as follows:

Prepare a solution having a color intensity equivalent to 0.004% of dextrose by dissolving 1 gram of C. P. dextrose in 500 cc. of water, diluting 20 cc. of this solution with 140 cc. of aqueous saturated picric acid solution, and making up to 200 cc. with water. Treat 10 cc. of this solution, containing 0.002 gram of dextrose, in the same way as described above. This standard is satisfactory for whites and whole eggs. For yolks and decomposed eggs, a weaker standard should be used. If the original sample contains 0.2%, or less, of reducing matter as dextrose, it is advisable to compare it with a standard equivalent to 0.2% of dextrose, or, if it contains less than 0.1% of reducing matter as dextrose, with a standard of 0.1% of dextrose. It is advisable in all cases to have about the same concentration of free picric acid in the standards as is present in the unknown solutions.

Calculations.-Dilute 5 grams of the sample to 100 cc.; finally dilute 10 cc. to 50 cc. The sugar standard with which it is compared contains 0.002 gram of dextrose in the same volume. Therefore Reading of standard × 0.002 × 200 Reading of unknown

Per cent of reducing matter as dextrose in sample =

Later in the year a sample of dried egg was sent to each collaborator for the determination of lecithin-phosphoric acid, as described by Leach2. Although few of the collaborators sent in any report, some gave very complete ones. The following suggestions and methods are taken from them:

1 Personal communication from David Klein, Division of Foods and Dairies, State Department of Agriculture, Chicago, Ill.

2 A. E. Leach. Food Inspection and Analysis. 3rd ed., 1913, 349.