Digitized by the Internet Archive in 2007 with funding from- IVIicrosoft Corporation http://www.archive.org/details/digestsulphurousOOunitrich Main Lib. Agric. Lcpt. '^ f ,6V %X'J' Issued November 22, 1907. United States Department of Agriculture, BUREAU OF CHEMISTRY— Circular No. 37. H. W. WILEY, Chief of Bureau. GENERAL RESULTS OF THE INVESTIGATIONS SHOWING THE EFFECT OF SULPHUROUS ACID AND SULPHITES UPON DIGESTION AND HEALTH.a INTRODUCTION. The relations of sulphurous acid to health are perhaps of greater importance than those of the preservatives already studied — namely, boron compounds and salicylic acid and its salts. The reason of this is found in the fact that the use of sulphurous acid at the present time is more general, and in certain classes of food products, according to the statements of manufacturers, more nearly approaches a necessity than is the case with boron or salicylic acid compounds. Sulphurous acid in some form is extensively employed in many technical operations in the preparation of foods. This is especially true in the production of wine, in the preparation of evaporated or desiccated fruits, and in the manufacture of molasses. The problem presents itself under two aspects — namely, the use of sulphurous acid or its compounds for technical purposes in the preparation of foods and its application to the finished products as a preservative. In the preparation of foods, sulphurous acid is chiefly employed in the form of the fumes of burning sulphur, applied either to the food products themselves in the course of manufacture or to the con- tainers in which the food products are held. In the ripening of the wines in cellars it is customary to fumigate the barrels with burning sulphur each time the wines are racked. In this manner it often happens that the wine before it is finally ready for sale on the market may have been placed in five or more freshly sulphured containers. By this treatment the wine absorbs a varying quantity of the sulphur- a By reason of the restrictions placed by law upon the printing and distribu- tion of bulletins exceeding 100 pages, it is not possible to supply the demand for Bulletin 84, Influence of Food Preservatives and Artificial Colors on Digestion and Health, from the regular edition. In order to give as wide a circulation as possible to the results of the experimental work, it has been deemed advisable, in the case of Part III, on Sulphurous Acid and Sulphites, as in the case of Part I, on Boric Acid and Borates, and Part II, on Salicylic Acid and Salicylates (Cir- culars 15 and 31), to publish the results in the form of a circular for general distribution. 16108— No. 37—07 1 ous acid, depending to some extent upon the amount of sulphur used in fumigating. Wlien sulphurous acid is used as a preservative for food products after the manufacture has been completed, it is usually employed in the form of bisulphite of lime or some similar preparation. Sulphur- ous acid has the property of uniting with certain organic radicals, such as aldehydes and some sugars, to form compounds which are more or less stable, and in this form it is known as combined sulphurous acid. IVlien it exists in the form of an absorbed gas or in combination with an ordinary metallic base, such as soda, potash, or lime, it is said to be in a free state. Combined sulphurous acid is set free from the or- ganic combination by treatment with an acid with the aid of heat or with a dilute alkali in the cold. In the accompanying report the effects of the combined sulphurous acid are not to be considered, except in so far as the combination takes place with the foods with which the sulphurous acid may be mixed after entering the stomach. The purpose of the investigation is, therefore, to determine practically the effect of free sulphurous acid — that is, sulphurous acid in a gaseous state absorbed by water or united with a base — rather than the effects of combined sulphurous acid. In no case has any question been considered in these investi- gations relating to the food value of the organic sulphur existing in proteids and other foods. t It is true that probably in the process of digestion complete saponi- fication of the combined sulphur compounds takes place, so that finally they appear in the small intestines in a free state — that is, as sulphurous acid or sulphites — and are then oxidized to sulphuric acid, as is the free sulphurous acid, during the metabolic processes. Practically, in the technical use of sulphurous acid in the manu- facture of food products only the fumes of burning sulphur are employed. Desiccated fruits, pared or unpared, are subjected, after the removal of the pit or core, to the fumes of burning sulphur in what is known as a " sulphur box." In the manufacture of wines a piece of so-called " sulphur candle " — that is, a piece of cloth which has been dipped in melted sulphur^s burned. This candle is attached to a wire, ignited, placed in the barrel, the bung inserted, and the candle allowed to burn until the whole of the sulphur is con- sumed. Previous to the sulphuring it is the custom to thoroughly wash the barrel so that the interior thereof at the time of sulphuring is moist. The moist surface of the wood absorbs the sulphurous acid more freely than does the dry wood. The ostensible object of the sulphuring is to keep the barrels sweet; in other words, to destroy any yeasts or other ferments which may adhere to the surface of the [Cir. 37] wood or be present within it. The barrels are often sulphured some days, or even weeks, before they are filled ; at other times the filling of the barrel with wine takes place immediately after the sulphuring. In both, cases notable quantities of sulphurous acid become diffused throughout the wine itself. It is evident that some care must be exercised in the use of sulphur in wine making for two very impor- tant reasons. In the first place, if too much sulphur be used, red wines would to a certain extent be bleached. In the second place, if the wines become entirely saturated with sulphurous acid the sec- ondary fermentations which produce the ripening of the wine would not take place. In such cases the wines apparently appear to be per- fectly mature within one or two years, whereas the proper maturation of a wine requires a much longer time. In the manufacture of non- fortified sweet wines much larger amounts of sulphur are used than in the manufacture of dry wines. This is an important fact, since it shows that the large quantities of sulphur are not necessary for the preservation of dry wines, because it is well known that red wines, which are generally very dry, are quite as well preserved as white, although containing much less sulphurous acid. It is claimed that in the manufacture of sweet wines — that is, those in which the natural sugars coming from the juice of the grape are not entirely fer- mented— larger quantities of sulphur are necessary to prevent fer- mentation after the wine is mature. If the sweet wine be made from a suitable kind of grape — that is, one w^hich is so rich in sugar that it gives a certain maximum quantity of alcohol and still leaves some unfermented sugar — it is evident that no excess of sulphurous acid will be necessary. In such a case the wine would be preserved by its natural alcoholic content. If, on the other hand, a sweet wine be made from a must so poor in sugar that it is necessary to add an additional quantity, the product can not be regarded as a natural wine, and hence there seems to be no necessity for providing for its manufacture. In the manufacture of sirups and molasses it is quite customary to expose the freshly expressed juices of the cane to the fumes of burn- ing sulphur. The " sulphur box " used in this case is so constructed that the juice, falling over shelves by gravity, absorbs the fumes of the burning sulphur rising from the box, which to this extent serves as a chimney. The sulphur dioxid becomes incorporated with the components of the juice, forming more or less stable compounds which are not entirely broken up by subsequent boiling. The sulphur in this form, as well as that which may still be present in the free state- — that is, either as an absorbed gas or in combination with metallic bases — passes into the finished product. When sugar is made the sulphur compounds are concentrated in the molasses and this con- [Cir. 37] centration becomes greater in proportion to the number of crops of sugar crystals removed. In very low grade molasses the sulphur naturally occurs in extraordinarily large quantities. In the preparation of evaporated apricots, peaches, pears, and man- darins sulphuring is practiced for the following reasons : 1. To produce as clear arid intense a yellow color as possible. 2. To conceal decayed portions of the fruit which have been over- looked in trimming. 3. To prevent fermentation and decay during the drying of fhe fruit. 4. To protect the fruit during drying from flies and other insects the larva? of which would otherwise develop after the fruit was stored. 5. To kill the cells of the fruit and thus make the texture more porous, which expedites drying. In the application of the fumes of burning sulphur in the prepara- tion of evaporated apples the principal object appears to be the pres- ervation of the color of the finished product. Fruits which have been sulphured before evaporation seem to have a lighter color than those which are dried without sulphuring. At the same time it is well known that highly sulphured fruits are preserved with a lower degree of desiccation than those not sulphured, and for this reason a greater weight of fruit is produced from a given weight of the raw material when sulphur is used. It is not difficult to preserve a water content of 30 per cent or over in the finished product when liberal sulphuring is practiced. The use of sulphurous acid also makes it easier to protect the finished product from mold and fungous growths in general after manufacture. That excessive quantities of sulphur are not necessary for the production of evajDorated fruits of pleasing appearance is well attested by analytical data obtained by the exam- ination of fruits purchased in the open market having a light and pleasing color and at the same time containing only a small quantity of sulphurous acid. On the other hand, it is quite easy by certain forms of treatment during the process of manufacture to obtain a product in which sulphurous acid is present in excessively large quantities. The analytical data also show that a portion of the sulphurous acid used in the preparation of such products becomes oxidized into sulphuric acid after a certain time, thus artificially increasing the small amount of sulphates naturally present in some food products, which does not appear to be a desirable practice. As sulphurous acid in some form is almost universally employed in the manufacture of wines, molasses, and sirups, and in the prepara- [Cir. 37] tion of desiccated fruits, it is evident that the prohibition of its use would necessitate a radical change in methods of manufacture. This fact, however, it might be stated, has nothing whatever to do with the purposes of the present investigation. Assuming that in the manufacturing processes certain added bodies are used which are found on investigation to be mjurious to health, the rational conclu- sion of such an investigation would be not to excuse or overlook the use of such bodies, but to institute investigations looking to their sup- pression. If, therefore, the results of the present study indicate that sulphurous acid, even in small quantities, is a deleterious substance when added to foods, it would be reasonable to expect that manufac- turers, as well as investigators, would immediately take steps looking to the early suppression of the injurious substance. While it is not likely that such an event could be accomplished within a year or two, it is reasonable to suppose that it could be eventually brought about without any disturbance to manufacture and without any diminution in the output of the article. In matters of this kind it is advisable to proceed when possible with conservative steps and to avoid any attempt at sudden and revolutionary changes in methods of manufacture. In all such cases, however, it will be found not only possible and desirable to make the food product in question without the use of the deleterious substance, but there is evidence to show that the products thus manufactured will be more palatable, more wholesome, and more valuable than those made according to the methods commonly used at present. Practical experiments have shown, for instance, the possibility of pro- ducing a high grade sirup from cane juice and other saccharine saps without the use of the fumes of burning sulphur. Analytical data show the presence on the market of considerable quantities of desic- cated fruits of good appearance in which the quantity of sulphur is so small as to be ascribed rather to the conversion of the natural sul- phur content of the product than to the addition of the sulphur in its manufacture. At the present time considerable quantities of wine are made without the addition of sulphur of any description, and these wines are of fine appearance, excellent flavor, and of noted purity and Avholesomeness. In so far as the mere tint of the food product is concerned, it is not a difficult matter to familiarize the public with a tint of a dif- ferent kind from that which would be produced by the use of sul- phur. The only arguments of any force favoring the use of sul- phurous acid in food products are those which relate either to the preservation of the food product or to its color. As the preservation of the product can be easily secured, and a slight change in color [Cir. 37] rendered familiar without working any hardship, these arguments seem to have no force whatever in justifjang the continuation of the use of sulphurous acid in foods. It may be the part of wisdom in the administration of food laws to tolerate existing methods of manu- facture for a certain length of time looking to their amelioration or change, but that is a question with which this investigation is not concerned. There is reason to believe, therefore, as a result of the present studies, which have shown that the use of sulphurous acid in foods is deleterious, that a rapid change will be made in the processes of manu- facture, looking to the complete and somewhat speedy suppression of its employment. The use of sulphurous acid and sulphites never adds anything to the flavor or quality of a food, but renders it both less palatable and less healthful. Every fact which has been brought out, therefore, in the investigation tends to accentuate the justness of the conclusion, nameh^, that the use of sulphurous acid in foods should be suppressed. ORGANIZATION OF THE EXPERIMENT. The organization of the work in general was practically identical with that of the previous investigations as reported in Parts I and II of Bulletin 84 and summarized in Circulars 15 and 31. The experiments were conducted on twelve young men from the Department of Agriculture and a local medical school, who voluntarily assumed the obligations imposed by work of this kind. They pledged themselves to abide by the rules and regulations guiding their conduct during the period of the observation, to indulge in no unusual exer- cise or study, to pursue the ordinary tenor of their daily lives without any more variation than is incident to regular habits. They further undertook to eat onty the food which was given them at the hygienic table, to collect and deliver for analysis the excreta of their bodies, to observe regular hours respecting sleep and work, and to report the quantity of water w^hich was drunk away from the hygienic table. The young men were not placed under surveillance, but simply were trusted with their pledge that they would not violate any of the rules of conduct prescribed. The diet was varied so as to give a choice of meats, vegetables, fruits, and cereals, with bread, butter, milk, and coffee. Food of the best quality was purchased, free of any added preservative or coloring matter and in a perfect state of preservation, and every precaution Avas used to have the food and all the appurte- nances of the table perfectly sanitary. [Cir. 37] ADMINISTRATION OF THE PRESERVATIVE. SCHEDULE OF ADMINISTRATION. The fore period in Series VII began on February 1, 1904, and the after period closed on March 11. The fore period extended over a period of ten days, the preservative period lasted twenty days, and the after period ten days, a total of forty days under observation. The divisions of the periods are shown in Table I. Table I. — Dates of periods and suhperiods, Series VII. Periods and subperlods. Date of begin- ning. Date of ending. Fore period First subperiod . . . Second subperiod . Preservative period. . . First subperiod . . . Second subperiod. Third subperiod . . Fourth subperiod . After period First subperiod . . . Second subperiod . 1904. Feb. 1 ....do... Feb. 6 Feb. 11 ....do... Feb. 16 Feb. 21 Feb. 26 Mar. 2 ....do... Mar. 7 1904. Feb, 10 Feb. 5 Feb. 10 Mar. 1 Feb. 15 Feb. 20 Feb. 25 Mar. 1 Mar. 11 Mar. 6 Mar. 11 Series XI and XIII, mentioned in the following pages, are special studies conducted at a later date. The purpose of these studies was to develop certain points in regard to the effect of the preservative on the blood and the distribution of the nitrogenous elements of the urine, to which the results obtained in Series VII had pointed as being of special interest and calling for further elaboration. The salt used for the administration of the sulphurous acid was sodium sulphite, and the quantity of SOo contained therein was cal- culated. About one-fourth of the weight of crystallized sulphite (NaoSOg 7 HoO) is composed of sulphurous acid (SOo). The total and average amounts of the preservative administered and all indi- vidual variations in the quantities taken may be found in Table II. Table II. — Schedule of administration of preservative. Series VII. Period and date. Sodium sulphite as SOo (capsules). - Sulphurous acid as SO2 (aqueous solu- tion). No. 1.- No. 2. No. 3. No. 4. No. 5. No. 6. No. 7. No. 8. No. 9. No. 10. No. 11. No. 12. 1904. First subperiod: Feb, 11 gms. 0.113 .240 .254 .254 .254 gms. 0.113 .240 .254 .254 .254 gms. 0.113 .240 ,254 .254 ,254 gms. 0.113 .240 .254 .254 .254 gms. 0.113 .240 .254 .254 .254 gms. 0.113 .240 .254 .254 .254 gms. 0.078 .178 .200 .200 .200 gms. 0.078 .178 .200 .200 .200 gms. 0.078 .178 .200 .200 .200 gms. 0.078 .178 .200 .200 .200 gms. 0.078 .178 .200 .200 .200 gms. 0 078 12 178 13 200 14 15 .200 200 Total 1.115 .223 1.115 .223 L115 .223 1.115 .223 L115 .223 L115 ,223 .856 .171 .856 .171 .856 .171 .856 .171 .856 .171 856 Average .171 [Cir. 37] Table II. — Schedule of administration of preservative, Series VII. — Cont'd. Period and date. Sodium sulphite as SO2 (capsules). Sulphurous acid as SO2 (aqueous solu- tion). No. 1. No. 2. No. 3. No. 4. No. 5. No. 6. No. 7. No. 8. No. 9. No. 10. No. 11. No. 12. 1904. Second subperiod: Feb. 16 gms. 0.508 .508 .508 .508 .508 gms. 0.608 .508 .508 .508 .508 gms. 0.508 .508 qms. 0.508 508 qms. 0.508 .508 .508 .508 .508 0.508 gms. 0 4(10 gms. 0.400 .400 .400 .400 .400 gms. 0.400 .400 .400 .400 .400 gms. 0.400 .400 .400 .400 .400 gms. 0.400 .400 .400 .400 .400 gms. 0 400 17 .508 .400 .508 1 .400 . 508 0 . 508 . 400 .400 400 18 508 rin« 19 .508 , .508 .508 ! .508 400 20 .400 Total... 2.540 .508 2.540 ;2.540 .508 1 .508 2.540 .508 2 540 '"> ?>4n 1 600 i'> noo 2.000 .400 2.000 .400 2.000 .400 2 000 Average .508 .508 .320 .400 .400 Third subperiod: Feb. 21 22 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 7fi2 .762 .762 .762 .254 0 .762 .762 .762 .762 .762 .400 .400 .400 .400 .200 .400 .400 .400 .100 .400 .400 .400 .400 .400 400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 400 23 400 24 ,25 .400 0 Total 3.810 .762 3.810 .762 3 810 i S mo 2.540 3.810 .508 1 .762 1.800 .360 2 000 1*^ (Vio 2.000 .400 2.000 .400 1 600 Average .762 .762 .400 .400 .320 Fourth subperiod: Feb. 26 .762 .762 .762 .762 .762 .762 .762 .762 .762 .762 .381 0 0 0 0 1.020 1.020 1.020 1. 020 1.020 ooooo ooooo ooooo .400 .400 .400 .400 ,400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 .400 0 27 28 0 0 29 0 Mar. 1... 0 Total 3.810 .762 3.810 .762 .381 .076 5.100 1.020 0 0 0 0 0 0 2.000 .400 2. 000 .400 2.000 .400 2.000 .400 0 Average 0 Entire preservative period- Total 11.275 .564 11.275 , .564 7.846 .392 12.565 .628 6.195 7 4fi5 !, ^ --^ V \ y V y t / / \ / \ / \ / \ A / s , / At — ■— __ / \ /\ y •^ / \ -'' T "7^ V -z \ ^ h-J- p- — ; ^^ ^ — P^ara ^ _ ^ -"^ ^1 ^~ ^^r- r / ' ' as^ ^^xT ".,. "."■- ■^- 1 — '~ T-[/ / \ 1 / \ ' tNio; 5 \ / \ / ^ / 5 735000 5635000 5 535000 ~—~~ -~^ 1 1 1 \ INIO^ -^-^^Ar- Ln,^^ — — ^ \ 5 335000 5235O00 5/35000 5035000 4 935000 4835000 5 535000 5435000 5 335000 5 23500O 5 135000 5035000 4935000 4835000 4 735000 4635000 4535000 4435000 5/27889 5027889 4927889 M /- '^^ /- \ "~" *"" — '^ ?.— 7" .^. H"" ^^-f--' ■-^^ '^ — ^ ^= =^-_- __ p_ __ \ 1 / T^ T^ \ / s. / s s, / N / A__ / __ ' — ' ■ ' ' ' — ' \ 1 h M*?5 ^ ^ ^ / ^ , ^i L__ ^^ r^ s^ r^' F-T- 7^- U— -; p^ .i^dk •^ kwj "■^ -4^ ;— —"1 r-^ ""S L"^* !\ / A — -"' ■ / \ \ \ / \ / J\ V \ •^ L. ^_j t 1 ! — L^ 1 _ ^ 1 \ / —^ 7^ r~~ — ' ^ \ / \ y \ ^ ' 1 ^ 1 1 { 1 . ____ __^ ™— 1 1 J 1 1 SUMMARV N°.s 1-2-3 RECEIVED SODIUM SULPHITE .— — - •-Kt— — L-U^4-a_l— UI-4-J-U.J-J — I— — 1 522/250 5 /2/ 250 502/250 492/250 i ] 1 I 1 ^^^^ 1 i 1 _- \ 1 1 I 1 i 1 1 ^^ SUMMARY Nos-4^5 RECEIVED SULPHUROUS ACID I.. - 1 1 _„ . 1 1 ^-L^ t^ — L_ ' 7 \ ~ t — ) ~i PRESERVAXIve PERIOD AFTER PERIOD (Reo BLOOD CfLLS • ^„^ ^ y white: blooo C£lls {f\/£fi4&£- iVM/rer SLOOO cells acw peRioo* Fl(3. 1. -Individual and summarized data, showing the effect of the preservative on the red and white blood corpuscles, Series XIII. [Cir. 37] 15 METABOLig PROCESSES. Nitrogen Metabolism. The general effect of the preservative upon the assimilation and excretion of nitrogen, as shown by the balance sheets, is not strongly marked. It is evident, however, that there is some disturbance of nitrogen metabolism, especially in inhibiting the absorption of nitro- gen in the intestines, inasmuch as both summaries agree in showing an increase of nonmetabolized nitrogen during the preservative period. There was a much more marked disturbance in the case of the subjects receiving sodium sulphite, those receiving sulphurous acid (representing a smaller ingestion of SO2) showing but little vari- ation from normal conditions. Phosphokic-Acid Metabolism. The summaries show that there is quite a marked tendency on the part of the preservative to derange in a measurable degree the metab- olism of phosphoric acid. Sulphur both as sulphite and as free sulphurovis acid tends to increase the quantity of phosphoric acid excreted in the feces and to decrease the quantity excreted in the urine. It may, therefore, be said to have a decidedly inhibiting effect upon the phosphoric-acid metabolism. Sulphur Metabolism. The most important point brought out by an inspection of the sulphur balance sheets is the increased elimination of sulphur over that ingested as preservative. There is an increase in both the urine and feces, the increase in the urine during the preservative period alone, in the case of the subjects receiving sodium sulphite, being greater than the amount of preservative sulphur ingested, while in the case of sulphurous acid the increase corresponds almost exactly to the amount of preservative sulphur ingested. The increase in the feces, considering the same tendency shown in the nitrogen and phosphoric-acid balances, can hardly be attributed to an elimination of preservative sulphur through this channel, but rather, as is before mentioned, to a decrease in assimilation and absorption from the ingested food. This fact, together with the probable increase in katabolic activities shown as regards the sulphur, indicates that the administration of the preservative produced decid- edly unfavorable effects. These tendencies are more marked in the case of sodium sulphite, though the variations in the conditions of the experiment must be considered in making this statement. [Cir. 37] 16 Table III. — Comparative summary of principal determinations made — Series VII. Sodium sulphite (Nos. 1-6). a Data. Body weight (kilos) Composition of feces: Weight (grams) Water content (per cent) Dry matter (grams) Urine: Volume (cc) Microscopic sediments (per cent of relative occurrence) c Albumin (arbitrary values for relative occurrence) d Sulphur (as SO3) : Neutral Inorganic Ethereal Total Metabolism (percentage results) : Nitrogen — Nonmetabolized (feces) Metabolized (urine) Phosphoric acids: Nonmetabolized (feces) Metabolized (urine) Sulphur: Nonmetabolized (feces) — Food sulphur only Including S in preservative Metabolized (urine)— Food sulphur only Including S in preservative Fore period. 63.71 82.00 72.50 23.00 1,092.00 54.50 0 .312 2.164 .165 2.642 7.50 85.10 29.93 60.03 11.20 82.55 Preserv- ative period. 62.78 103.00 76.15 25.00 1,139.00 66.70 13 .419 2.729 .167 3.316 8.54 87.17 36.34 58.82 12.13 10.16 106.66 After period. 62.28 85.00 75.40 21.00 1,076.00 65.50 7 .372 2.104 .156 2.631 7.47 88.17 29.91 57.60 10.05 85.32 Sulphurous acid (Nos. 8-11). 6 Fore period. 87.00 74.97 22.00 1,195.00 .281 1.943 .140 2.364 8.04 80.55 32.81 53.66 11.05 74.09 Preserv- ative period. 62.00 102. 00 76.60 24.00 1,402.00 .371 2. 249 .155 2.774 8.78 79.10 37.13 52.85 11.85 10.42 78.52 After period. 62.07 115.00 77.63 26.00 1,415.00 .409 2.016 .142 2. 567 9.26 81.13 36.66 51.01 11.73 80.31 " Received an average of 0.472 gram per day of SO-.. ^ Received an average of 0.343 gram per day of SO^." ^Nos. 1 to 12. <* Calculated only for subjects who showed no albumin in fore period, to 12. including Nos. 1 GENERAL CONCLUSIONS. From a careful consideration of the data in the individual cases, and the summaries of the results, it appears that the administration of sulphurous acid in the food, either in the form of sulphurous-acid gas in solution or in the form of sulphites, is objectionable and pro- duces serious disturbances of the metabolic functions and injury to digestion and health. This injury manifests itself in a number of dif- ferent v^ays, both in the production of clinical symptoms which indi- cate serious disturbances, malaise, or positive suffering, and also by inducing certain changes in the metabolic processes which are not manifested in the way of ordinary clinical symptoms, and are only detected by careful chemical and microscopical study of the excretory products. It can be safely said from the evidence adduced that the administration of sodium sulphite and sulphurous acid, as above indi- cated, produces a marked influence of an unfavorable character on metabolism. As a result of this action, an assimilation of food mate- rials containing organic phosphorus is retarded, while there is evi- dence of increased sulphur katabolism. The sulphur balance sheets [Cir. 37] 17 show what an immense burden has been added to the already over- worked kidneys, which are called upon in this case to remove nearly all, if not quite all, of the added sulphur from the body, previously converted, in great part, to sulphuric acid. It is not possible that placing upon the kidneys this increased work of excreting sulphur can result in anything but injury. The fact that the microscopic crystal- line and amorphous bodies in the urine are increased in number under the influence of the added sulphur, is another indication of the extraordinary demands made upon the kidneys in such circumstances. This increase is interesting in respect of the effect which the con- tinued exhibition of sulphurous acid must eventually have upon the structure of the kidney. It is reasonable to suppose that the con- tinued use of a body Avhich produces such results would cause lesions of a histological character that eventually would develop conditions Avhich would give serious apprehension. In the nature of these exper- iments it was not possible to examine the organs of the body histolog- ically and hence the above conclusion is only based upon experience of a similar character where the organs in question have been subject to such examinations. "V^Hiile there might be no distinguishable lesion of the kidneys produced during a period of twenty or thirty days, or even longer, it is plain that, sooner or later, lesions of a very serious character, producing organic diseases, possibly of an incurable type, Avould be induced. The further observation that there is a marked tendency to the production of albuminuria, although of an incipient character, is an indication of the unfavorable results of the adminis- tration of the sulphurous acid. It is, therefore, evident that by increasing the burden upon the excretory organs, the administration of sulphur in the form mentioned is highly detrimental to health. All of these tendencies can not be interpreted as being other than of a decidedly harmful nature. Another effect which the administra- tion of the sulphur produced, and one of a more serious character still, is found in the impoverishment of the blood in respect of the number of red and white corpuscles therein. The administration of a sub- stance which diminishes by a notable percentage these important component particles of the blood must be regarded in every sense as highly prejudicial to health. Some of the most important functions of the blood, as has been well established by careful physiological studies, are intimately connected with the number and activity of both the red and white corpuscles. The bleaching effect of the sul-. phurous acid upon the color of the blood is a matter of less conse- quence and no great effect is produced upon the hemoglobin, but the diminution of the number of red and white corpuscles is a matter of serious concern. [Cir. 37] 18 The variations of the metabolic processes, from the normal, as indi- cated in this series of experiments, were never of a character favora- ble to a more healthy condition of the system, but, on the other hand, all these variations, in so far as the effect of the changes could be dis- tinguished, are of a prejudicial character. There is no evidence what- ever that the sulphur added to the foods in the form of sulphurous acid or sulphites takes any part in the nutrition of the tissues of the body containing sulphur, namely, the proteids; hence no claim of food value can be established for these bodies. The evidence all points to the fact that they are purely drugs, devoid of food value, having no favorable effects upon the metabolic processes, but, on the other hand, exerting deleterious and harmful effects. The conclusion, therefore, is inevitable that as a whole the changes produced in metabolic activ- ity by the administration of sulphur in the forms noted above in the comparatively short time covered by the experiments are decidedly injurious. The verdict which must be pronounced in this case is decidedly unfavorable to the use of this preservative in any quantity or for any period of time, and shows the desirability of avoiding the addition of any form of sulphurous acid to products intended for human food. [Cir. 37] RETURN MAIN CIRCULATION TO^ ALL BOOKS ARE SUBJECT TO RECALL " " RENEW BOOKS BY CALLING 642-3405 DUE AS STAMPED BELOW FEB 01 U 96 RECEIVED NOV 0 2 1995 CIRCUUTION DEF - FORM NO. 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