heating not carried beyond 90° C., little or no color is given by formaldehydefree milk; but if, on the other hand, the acid is in excess or the heating is carried too near the boiling point, the proteid reaction, becomes a factor increasing with the excess of acid and with the temperature.

Applying these results to the method referred to, it would appear to be desirable to replace the expression "about" [line 1 (e), p. 185, Bul. 107, Rev.] with the specification that equal (measured) quantities of the strong acid reagent and milk must be used, and to warn the analyst against the excessive use of either acid or heat, since either may produce a color hardly distinguishable from that given when formaldehyde is present.

The fact that the color given by formaldehyde develops much more quickly than that given by proteids alone may also be taken as a rough guide, but is of little value when the acid is in great excess.

SULPHUROUS ACID.

A great deal of attention has been given during the last year by the Division of Foods of the Bureau of Chemistry and the branch laboratories in San Francisco and New Orleans to the determination of sulphurous acid in dried fruit and molasses. In connection with the work, various methods for the determination of sulphurous acid were carefully studied in all three laboratories. In the New Orleans laboratory the work was done by A. Hugh Bryan with the assistance of C. O. Dodge and C. M. Boyles; in the San Francisco laboratory the work was done by Ralph A. Gould, E. J. Lea, and others; in the Bureau of Chemistry at Washington by M. C. Albrech, F. W. Liepsner, P. B. Dunbar, and C. P. Wilson.

It was found that the most satisfactory results were obtained with a longnecked, round-bottomed Kjeldahl flask of 500 cc capacity. Twenty grams was the maximum amount of dried fruit which could be used advantageously. On the addition of water the fruit swelled up so that a larger amount caused difficulty in boiling. In the case of molasses, 50 grams was the maximum amount that could be advantageously distilled. The use of larger samples in correspondingly larger flasks was found to be unsatisfactory.

Foaming, which occurs in both classes of products, appears to be best controlled with paraffin. Sodium chlorid deters the foaming with dried fruit to a certain extent, but the benefit derived from its use does not appear to be uniform. A current of carbon dioxid when introduced above the liquid materially decreases foaming, but when it enters at the bottom of the flask foaming seems to be increased.

It has been suggested by C. S. Ash that the volumetric method be modified by distilling into a normal solution of potassium hydroxid instead of into a standard iodin solution as is customary. The experiments by Messrs. Gould and Lea do not indicate that this method is advantageous. The average of the results obtained by it are very slightly higher than those obtained by distilling into iodin, but such results are somewhat irregular and duplicates are not altogether satisfactory. If it is impossible to titrate immediately after distillation the potassium hydroxid method has an advantage, as the oxidation of the sulphite occurs very slowly. Some delay may, therefore, follow the distillation in such case. It is essential, however, that titration follow immediately the acidification of the distillate. In case of distilling into iodin, the distillate should be titrated immediately.

Objections to the volumetric method have been repeatedly made, especially by Horne, because of the hydrogen sulphid said to be eliminated from molasses

a U. S. Dept. Agr., Bureau of Chemistry, Bul. 105, p. 125.

on boiling with acid. It has been recommended that the hydrogen sulphid be eliminated by passing the distillate through a trap containing cadmium chlorid or copper sulphate. The results obtained by the use of the trap with both dried fruit and molasses were found to be unsatisfactory. The efficiency of the apparatus was often somewhat reduced, although such reduction did not appear to be due to the presence of hydrogen sulphid, as no deposit of sulphid was found. A slight black deposit was sometimes found in the case of the molasses samples, but examination showed that it did not consist of copper sulphid. It therefore appears to be definitely proven that the amount of the hydrogen sulphid eliminated in the determination of sulphurous acid in dried fruits and molasses is so slight as not to interfere with the accuracy of the operation.

Zerban (page 77) has found that satisfactory results in the determination of sulphur dioxid in molasses can only be obtained by diluting 50 or 100 grams of the sample to 1,000 cc and distilling 800 cc. Even then an additional amount of distillate would contain some sulphur. Bryan and his associates found it unnecessary to employ such dilution or to distil so great a volume. His method was to dilute 50 grams of molasses with 100 cc of water, distil until the foam turns darker, add by means of a separatory funnel 3 portions of water of 50 cc each, and continue the distillation as long as possible after each addition. was found that practically complete results were obtained by this method. In the case of dried fruit, Gould found that satisfactory results could be obtained by treating 16 grams of the sample with 175 cc of water and distilling to a small volume. From the consequent concentration more complete results are obtained than from the distillation of a much larger but less concentrated volume.

It

Practically complete results were obtained in Washington by treating 20 grams of dried fruit with 300 cc of water and distilling 150 cc. Almost all of the sulphur dioxid was contained in the first 100 cc of the distillate, and the amount contained in portions of the distillate following the first 150 ce contained sulphur dioxid in negligible quantity, if at all.

It was demonstrated in all three laboratories that the greatest care must be exercised to prevent charring, especially if the volumetric method is employed. Charring evidently produces a reducing substance which gives a false indication regarding the amount of sulphur dioxid present. Bryan suggests guarding against this by placing the flask upon an asbestos board and exposing but a small surface to the flame. In all three laboratories, and especially in San Francisco and New Orleans, a careful and exhaustive comparison was made of the reliability, efficiency, and accuracy of the volumetric with the gravimetric method. The results obtained with the gravimetric method are slightly higher in the presence of a small amount of sulphur dioxid. In the presence of larger amounts the results are comparative in both molasses and dried fruits. Comparative results with the two methods were obtained in New Orleans with molasses containing 380 milligrams and more of sulphur dioxid per kilogram.

Gould and Lea studied carefully the sources of inaccuracy in the volumetric method which depends on receiving the distillate in iodin and titrating the residual iodin. They found that the chief source of inaccuracy lay in the volatilization of the iodin which is considerable when a current of carbon dioxid is employed. This volatilization was most pronounced when a beaker was used as a receiver, but was excessive even when a flask was employed. Traps were ineffective when attached to an ordinary flask, as cork stoppers were found to absorb quite an amount of iodin and rubber stoppers were still more objectionable.

The best results by the volumetric method were obtained with 8-ounce Drechsel wash bottles, attached to a trap provided with 5 cc of N/50 thiosulphate

solution. By this means the loss was reduced to 0.2 cc of N/50' iodin solution. The efficiency of the gravimetric method with both peaches and molasses is much greater in the presence of a large amount of sulphur dioxid than in the presence of a small amount. According to the results obtained in Washington, in the presence of 200 milligrams of sulphur dioxid per kilogram of fruit, the efficiency amounts to but 45 per cent; with 500 milligrams, to 70 per cent; with 1,000 milligrams, to from 70 to 75 per cent, and with 2,000 milligrams to about 85 per cent of the sulphur dioxid present. This was as large a percentage as could be recovered regularly with dried fruit. In the New Orleans laboratory the efficiency ranged from 83 to 89 per cent in molasses whose content of sulphur dioxid varied from 100 to 3,300 milligrams per kilogram. As with the dried fruit, the greater efficiency was secured in the presence of the larger amount of sulphur dioxid.

According to the results obtained both at San Francisco and New Orleans, the use of carbon dioxid may be greatly reduced. It can be advantageously employed to remove the air from the flask before beginning the distillation, but the current may then be stopped without sacrifice. Mr. Bryan found that equally good results were obtained by dispensing with the current of carbon dioxid and using instead a solution of sodium bicarbonate, the acidity being increased correspondingly. The purity of the reagent should be tested by making blank determinations for sulphur trioxid, as some blanks will run as high as 50 to 60 mg per kilogram. In the New Orleans laboratory blanks were made daily and the results subtracted from the determinations for that particular day.

LEGISLATION ON PRESERVATIVES IN FOOD.

By H. L. HARRIS, Pacific Coast Borax Company.

When William H. Moody was Attorney-General he said: "A thing may be within the statute but not within the letter, or within the letter and not within the statute. The intent of the lawmaker is the law." The pure food law was enacted for the purpose of protecting consumers from being defrauded or injured by adulterated food products, and to compel merchants to truthfully label their goods. Among the matters it aims to regulate is the use of preservatives in food. By authority of this law Food Inspection Decision 76 says: "It has been determined that no drug, chemical, or harmful or deleterious dye or preservative may be used. Common salt, sugar, wood smoke, potable distilled liquors, vinegar, and condiments may be used." It is evident that the food inspectors consider salt, sugar, smoke, alcohol, vinegar, etc., innocent, wholesome preservatives. I do not suppose that they would have us believe that these substances may not, under some conditions, be injurious. In regard to this latter point various authorities express themselves as follows:

SALT.

The United States Dispensatory, page 1249: "Sodium chlorid in small doses acts as a stomachic tonic and anthelmintic, in larger ones as a purgative and emetic."

Food and Dietetics, Hutchison, page 291: "It has been asserted, for instance, that the addition of salt to the food aids digestion (Ogata), but more recent and exact experiments have shown that in health, at least, and in moderate doses salt has very little real influence on digestion at all, while in large quantities it actually delays the process."

Practical Hygiene, Harrington, page 209: “In the process of salting, the soluble organic constituents of meat and fish are removed in large part, and the fibers become hardened. The nutritive value and digestibility therefore are diminished correspondingly. Brine salting of fish is one of the oldest processes of preservation known."

Farmers' Bulletin 183, page 29: "Salt is an astringent, and when applied alone to meat renders it very hard and dry. Its action is first to draw out the meat juices. In a few days it will contract and harden the muscle fibers, thus shrinking the volume of meat."

Salt is a natural constituent of the blood. In small quantities it is, without question, beneficial and even necessary to health. When it is used, however, in large quantities to cure or preserve meats, fish, etc., it undoubtedly lessens the flavor, diminishes the food value, and renders food thus preserved or cured more difficult to digest. Unless its use is properly controlled it may be distinctly injurious to health.

SUGAR.

* * **

Food and Dietetics, Hutchison, page 275: "In strong solution sugar is an irritant to the tissues. In contact with the skin it is apt to set up superficial inflammation. This is familiar in the form of eczema, which is apt to appear in diabetics from the contact of the sugar-containing urine with the skin, and from the similar condition occurring on the arms of grocers and other persons who have frequently to handle sugar, and it is on account of its irritating properties that sugar can not be used as a subcutaneous aliment. The same is true of the stomach. Brandl, experimenting on dogs, found that a 5.7 per cent solution of sugar produced reddening of the mucous membrane; if the concentration was increased to 10 per cent the mucous membrane became dark red, while a 20 per cent solution produced pain and great distress. This irritating effect on the mucous membrane is accompanied by the production of much mucus and the pouring out of a highly acid gastric juice."

The above evidence clearly indicates that sugar may be injurious to the cuticle or mucous membrane.

SMOKE.

Practical Hygiene, Harrington, page 209: "Smoking consists in exposing the meat or fish to the action of the smoke of wood fires, after, as a rule, a preliminary salting. The exposed material, already deprived of part of its natural moisture, becomes dried still further, and is partly penetrated by acetic acid, creosote, and other preservative elements of smoke."

* * *

Preservatives in Food and Food Examination, Thresh and Porter, page 9: "Several articles of food are frequently preserved by being exposed to the smoke from smoldering wood or sawdust. During this process they are partially dried and the material absorbs certain antiseptic substances from the smoke. Creosote is probably one of the active antiseptic agents. It is a very poisonous substance, and doubtless a great outery would be raised were anyone to attempt to use it for preserving food, but so long as it is introduced into the food in an old-fashioned manner, no objections are raised. It is only when some one wishes to improve upon ancient methods that the effect of prejudice and conservatism makes itself felt. It has never been alleged, so far as we are aware, that smoked meat is unwholesome, though its digestibility is almost certainly impaired. Any modern system of preserving which affected the digestibility to a similar degree would be strongly condemned.”

50056-Bull. 116-08- -2

ALCOHOL.

Food and Dietetics, Hutchison, page 343: "The bad effects of alcohol taken in quantities sufficient to produce intoxication are too apparent to require to be insisted upon. It must be remembered, however, that the habitual consumption of alcohol in quantities which, though insufficient to produce any outward and visible signs of intoxication, are yet beyond the immediate oxidizing power of the cells, may end by playing havoc with the tissues. Here, again, the brain seems specially liable to suffer, probably owing to its being one of the most highly organized and delicate tissues of the body. Throughout the body generally the presence of even a slight amount of undecomposed alcohol leads to a diminution of the chemical energy of the cells, which interferes with the ordinary course of metabolism, and may result in chronic disease.”

VINEGAR.

66

* *

Food and Dietetics, Hutchison, page 284: Although the acetic acid which vinegar contains is ultimately oxidized in the body, with the production of alkaline compounds, there is still reason to believe that it has an unfavorable influence in gout, and may even precipitate an attack if freely indulged in."

Preservatives in Food and Food Examination, Thresh and Porter, page 93: "Vinegar is a very popular condiment and preservative. Taken in excessive quantities it interferes with the digestive processes, and its use in such quantities, if persisted in, ultimately causes emaciation. Used in moderation, however, it is not likely to produce injurious consequences; nevertheless, if it were not one of the oldest preservatives in use, objections would be raised to its introduction. The effect of excessive quantities on adults and children and its potential effect on invalids would be dilated upon, and its use probably condemned."

It follows from the above facts that the preservatives deemed innocent are, under certain conditions, capable of producing distinct injury to the digestive system. The use of certain other preservatives is not permissible under FoodInspection Decision 76. Among these the boron preservatives are included. In the effort to eliminate harmful substances from food much has been said about the use of boron preservatives, and the conclusion has been reached by some that they are actually harmful. After a most careful, and, as far as possible, unprejudiced consideration of the facts in the case, and after advice with many professionally competent to form an opinion upon this question, it is my honest conviction that boron preservatives are less injurious to health than the substances permitted by Food-Inspection Decision 76. If this is true, the fact will in time be recognized. When it is recognized we will want to make use of the available means that are most efficient. The boron preservatives far outweigh, in their preserving properties, the substances permitted by Decision 76. True, if the question of quantity is ignored, and if conditions not existing in preserved foods are considered, facts may be arrayed against boron preservatives precisely as we have found them in the case of common salt, sugar, wood smoke, potable distilled liquors, and vinegar. But if such facts are not prohbitive against these preservatives of the ancients, why should they be given greater weight against our modern preservatives? While it is true reports have been circulated that boric acid and borax have been injurious to health, when such reports are scientifically investigated the facts invariably show that it was not food preserved with boron compounds, but that excessive doses had been administered medicinally, Boron compounds should not be condemned as food