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teresting chemical and metallurgical plants could be visited in and around St. Louis. The papers of the Symposium on Potash were then read. The paper by J. C. W. Frazer, W. W. Holland and E. Miller of the Johns Hopkins University on “A New Method for the Recovery of Salts of Potassium and Aluminum from Mineral Silicates” gave the results of experiments in which finely ground feldspar was treated with caustic soda solution a t zoo to 300’ C. One molecule of SiOz was extracted from the feldspar. The resulting product is readily acted upon by dilute acid producing a salt of potassium, the silica and aluminum remaining undissolved. On treating this residue with sulfuric acid, aluminum sulfate would be produced, the silica being filtered off. The caustic soda is regenerated by treatment with lime and can be used again. As a very pure silica is obtained by this process as well as aluminum sulfate and potash salts, it may prove profitable even after the war. The paper on “Potash from Waste Liquors of Beet Sugar Factories” by H. E. Zitkowski was then read. This paper gave a n analysis of the total amount of potash in the sugar beets produced in the United States. A considerable amount of the potash is being utilized a t present as a constituent of cattle food or fertilizers in various forms. The waste waters contain both nitrogen and potash. The method a t present being experimented upon consists in evaporating the waste water and incinerating to recover the potash. The paper on “The Possibilities of Developing an American Potash Industry,” by Richard K. Meade, gave a general discussion of the various methods being used and more particularly the methods by which potash is recovered as a by-product in the cement and iron and steel industry. The very interesting conclusion was reached that about two-thirds of the requirement of the American market could be supplied from this source. A short paper on “The Potash Industry of Canada” was read by E. B. Biggar, of the Canadian Chemical Journal. I n the course of the discussion the problem of evaporation of dilute solutions was taken up by Hugh K. Moore and the methods
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in use in California for the recovery of potash from kelp were given a t considerable length by H. 0. Chute of Los Angeles. After luncheon the party proceeded by automobile to Niagara Falls stopping a t the Curtiss aviation field to observe aeroplane flights. A t Niagara Falls the gorge ride was taken in a special car after which the party proceeded by the automobiles to Goat Island where light refreshments were served and then returned by automobile to Buffalo. Friday evening the subscription dinner was held at the Hotel Statler. About 60 covers were laid, the dinner being a joint dinner of the Buffalo Engineering Society and the American Institute of Chemical Engineers. President G. W. Thompson acted as toastmaster. hlaximilian Toch gave a good many interesting instances of important war service rendered by American chemists. At the conclusion of his remarks, he proposed a toast to President Wilson which was heartily responded to. Professor A. W. Smith of Case School of Applied Science spoke of the war service rendered by the schools and colleges. Professor Wm. P. Mason, of Rensselaer Polytechnic Institute was introduced as the water expert who would speak on prohibition as a war measure. F. A. Lidbury was introduced as the newly elected president of the Buffalo Engineering Society, and spoke of the attempt being made in Buffalo of having but one technical society, including in its membership all branches of engineering as well as chemists and chemical engineers. Mr. David C. Howard who hadwelcomed the Society to Buffalo was then called upon t o say a fitting parting word. The dinner ended with the singing of The Star Spangled Banner. Saturday morning a few of the members visited the plant of the J. P. Devine Co. The attendance a t the meeting was excellent throughout, about IOO being present a t the various sessions. The entire meeting was marked by a patriotic spirit of desire to be of the greatest service to the country and Government during the present crisis. COOPI~R UNION July 1 1 , 1917
J. C. OLSEN,Secretary
NOTES AND CORRESPONDENCE ON THE SUBSTITUTION OF PERCHLORIC ACID FOR CHLORO-PLATINIC ACID IN THE DETERMINATION OF POTASSIUM Editor of the Journal of Industrial and Engineering Chemistry: Your recent editorials in THISJOURNAL prompt me to suggest that the chemist, himself, may directly aid in the conservation of our platinum supply, by the substitution of perchloric acid for chloro-platinic acid in the determination of potassium. I have made inquiries in regard to the reliability of this method and find that it is coming into general use quite rapidly. Among my informants are a number of the instructing staff of the Massachusetts Institute of Technology, and several soap and fertilizer manufacturers who are using the perchloric acid method in preference t o the more expensive platinum method. This question of cost is well brought out when it is noted that the cost of chloro-platinic acid for the determination of one gram of potassium is approximately $8.00 at the current market price, while the cost of sufficient perchloric acid for the same determination is slightly over 3 cents. Including the loss of platinum, cost of recovery, and the money tied up in a small bottle of this reagent, it is seen that the platinum method is overwhelmingly more expensive than the perchlorate method. It should also be borne in mind that the German Fertilizer Chemists have adopted the method as official. It is to be regretted t h a t our own soil and fertilizer methods are so slow in being revised.
Mr. P. L. Hibbard recently published the results of an inand made vestigation on the two methods in THISJOURNAL, a n error in the price of the acid. The following quotations from a chemical supply house make this evident: “No. 1 Perchloric acid C . P. (60%) 5 pounds.. .............................. $33.00 1 pound.. 7.20 I ounce.. ............................... 0.75(a) (a) As this is for experimental purposes, only one order for this amount will be filled.”
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Mr. Hibbard’s conclusions are not entirely borne out by my experience in regard t o the ease of manipulation and the length of time required, as I find the perchlorate method quite rapid. Clarence Scholl published an article in the Journal of the American Chemical Society, 36 (1g14),208j, which confirms my experience. EDWARD c. WALKER, 3 R D BATAVIA,N. Y.
THE CHEMICAL COMPOSITION OF COMMERCIAL GLUCOSE AND ITS DIGESTIBILITY-A REJOINDER Probably no paper that has appeared in recent numbers of THIS JOURNAL has aroused a greater amount of unfavorable discussion among a certain class of its readers than the one in the November issue of 1916,upon “The Chemical Composition of Commercial Glucose and Its Digestibility,” by J. A. Wesener and G. L. Teller.
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One of the first difficulties experienced in reading the paper of \\-esener and Teller is that of reconciling the experimental part of their paper with the final “Summary and Conclusions.” The inconsistencies between these two parts are so pronounced that the reader is forced to suspect that “Summary and Conclusions’’ has no connection with the rest of the paper, but is only a sort of tag which can be attached or detached a t the authors’ pleasure. This suspicion has, indeed, considerable outside evidence for substantiation. The “Summary and Conclusions” of LVesener and Teller‘s paper w a s presented, exactly as printed on pages 1019 and I O Z O of Vol. 8 of THIS JOURNAL, before a meeting of the Illinois State Food Standards Commission, which was held in Chicago in June, 1916. This meeting, according to the statement by its Chairman, mas called by one of the large producers of commercial glucose for the purpose of revising the standards of certain foods “so that there might be a more liberal use of corn syrup, commercial glucose, in them.” Wesener and Teller were two of the witnesses to appear a t this hearing. For some unknown reason these authors neglected to add 1.0 their paper, when printed in THISJOURNAL, the customary note that it had been previously presented either by summary or title. Whatever the reasons may be for this omission, the fact remains that four months before its publication in THISJOURNAL, the “Summary and Conclusions” of Wesener and Teller’s paper was printed verbatim in the American Food Journal (July, 1916, pp. 300 and 301). It is curious to note that after the publication of Wesener JOURNAL, “Summary and Conclusions” and Teller’s paper in THIS was again detached and once more printed in the American Food Journal (December, 1916, p. 6 2 3 ) , this time with the rather naive Editorial Statement that it was reprinted through the courtesy of T h e Journal of Industrial and Engineering Chemistry. This attachable and detachable tag, through the courtesy, no doubt, of the American Food Journal in which it first appeared, has also been reprinted in various other trade publications. The main thesis which U‘esener and Teller attempt to establish is that when used as a food commercial glucose “pound for pound of dry weight, will furnish a t least as much energy as does cane sugar.” But in studying the authors’ experiments to demonstrate this, the reader is first puzzled to know whether raw or refined cane sugar is meant. The dry matter of commercial glucose, according to the authors’ own analysis, contains about 0 . j per cent of mineral matter and this might seem to indicate that they had in mind a raw cane sugar containing a n equivalent amount of mineral impurities. The reference (p. 1011) which the authors make to the molecular equivalents of cane sugar and dextrose shows, however, that pure sucrose or refined sugar was the intended basis of comparison and this helps to explain the efforts of the authors to conjure away the mineral impurities of commercial glucose in their “Summary and Conclusions.” I n the experimental part of their paper (p. IOIO) we find for example, 0,34 per cent of ash in the liquid glucose, while in the detachable “Summary and Conclusions” on p. 1019, this amount dwindles to “a trace” and then to “mere traces.” Half a per cent of ash in thedry matter of cane sugar is regarded by refiners as something more than “mere traces.” There is a device in music by which discordant tones are sometimes made to diminish in intensity until they completeiy vanish, but it has remained for the authors to employ the diminuendo as a method of chemical research. But i t is in the fallacious conclusions which the :authors draw from their fermentation experiments that we are chiefly concerned. The error due to the employment of impure yeasts in separating fermentable from non-fermentable carbohydrates has long been recognized. The authors state themselves that “the amount of gas ordinarily produced from j g. of cane sugar, when 15 g. of compressed yeast were used, varied from 1050
to I roo cc.” or in other words, a variation of some 4.5 per cent. Herzfeld found mako-dextrin to be completely fermented by yeast, whereas Brown and Morris found the dextrin and maltodextrin of starch conversion to be unfermented by a pure culture of Saccharomyces ccreviseae but to be strongly attacked by Saccharomyces ellipsoideus and Saccharomyces Pastorianus.1 The percentages of dextrin, maltose and dextrose which Wesener and Teller calculate from results obtained with ordinary bakers’ yeast have absolutely no scientific value. These authors very correctly express their percentages in Table I, as apparent percentages but in the detachable “Summary and Conclusions” the qualifying adjective apparent has for some reason been omitted. Still more unconvincing is the experimental evidence by which the authors attempt to disprove the existence of isomaltose or gallisin in the unfermentable residues of commercial glucose. It has long been known that the unfermentable residues from the acid or diastatic conversion of starch could be largely hydrolyzed into dextrose by means of acids and it is somewhat strange that Wesener and Teller failed to mention the work of previous investigators along this line. If they had carefully reviewed the literature upon the subject they would have discovered why heating the unfermented residues of commercial glucose with hydrochloric acid never produces complete conversion of the products into dextrose. T i e authors, for example, in their experiments with pancreatin and taka-diastase (p. 1015, Table 9), after boiling the unfermented matter of commercial glucose with 2 .j per cent hydrochloric acid, neutralizing and again fermenting, obtained a non-protein organic residue of 0.440 g. from 6 g.2of commercial glucose in case of pancreatin and 0.380 g. from 6 g. of commercial glucose in case of taka-diastase-results which are equivalent t o 7.33 and 6.33 per cent, respectively, of the original glucose or, when calculated to a moisture-free basis, about 9 and 8 per cent, respectively, of the commercial glucose solids. A parallel fermentation experiment upon 5 g. of sucrose gave a final nonprotein organic residue of 0.09 g. or 1.8 per cent. Wesener and Teller state that the remaining unfermented matter of their glucose experiments in their opinion “may be justly attributed to organic acids produced in one or both of the fermentations.” If we take the 1.8 per cent of residue in the sucrose experiment, as the amount of organic acids, glycerol, etc., etc., formed by the action of yeast, there still remains over 5 per cent of matterS unaccounted for. It is difficult, therefore, to understand the statement of the authors (p. 1015) “that all the products of glucose are accounted for and that there does not remain any substance which was a constituent of th; glucose and which cannot by the process used be converted into substances fermentable by yeast.” If Wesener and Teller had only consulted the previous work of Gatterbauer they might have spared themselves the necessity of making so unwarranted an assumption. Gatterbauer4 obtained from the unfermentable residue of a sample of commercial glucose, by purification with alcohol and ether, a preparation of so-called gallisin, which, after fermenting away the traces of dextrose and maltose, gave a well characterized osazone, corresponding to the formula, CaH32N409, of a disaccharide. The osone from this preparation was hydro1 For a review of these experiments see Sykes and Ling, “The Principles and Practice of Brewing.” 1907, p. 159. 2 M y attention has been called to a slight error in this calculation. The 6 grams were taken by mistake from the data given a t the top of Table 9. Calculation of the results to 4.8 grams glucose would increase the unfermentable non-protein organic residue to 9.17 per cent and 7.92 per cent, respectively, of the original glucose, or about 11 per cent and 10 per cent, respectively, of the commercial glucose solids. 8 Actually 6.7 per cent on the basis of the average of the figures as corrected in the above footnote. & F o r a review of Gatterbauer’s work see Wichelhaus, “Der Starkezucker,” 1913, p. 92.
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lyzed with hydrochloric acid into dextrose. The disaccharide thus corresponds in properties t o the unfermentable sugar isomaltose. Gatterbauer then attempted t o hydrolyze his preparation of gallisin directly into dextrose by heating IOO cc. of a 14.7 per cent solution with 50 cc. of 0.75 per cent hydrochloric acid for three-quarters of an hour upon the water bath, but a small percentage of material failed to undergo hydrolysis. Instead of assuming, however, that all his products were accounted for, Gatterbauer next tried the effect of using stronger acid when he found t h a t he was further away from complete hydrolysis than he was before. Reversion of the dextrose, which had been formed, had taken place, and gallisin, or isomaltose, was being regenerated. The complete hydrolysis of the unfermentable residues of starch conversion into dextrose by means of hydrochloric acid was thus shown to be impossible, for the reaction, as first pointed out by Wohl,’ in 1890, is reversible. Ost2 has also shown that with Sacchse’s method of hydrolysis with 2 . 5 per cent hydrochloric acid, the theoretical factor of 0.90, for converting dextrose to starch, is several per cent too low on account of the formation of reversion products. Wesener and Teller, by boiling the unfermented residues of commercial glucose with 2.5 per cent hydrochloric acid, were, therefore, producing the very compound or compounds, whose existence they have attempted t o explain away. The statement of these authors in their detachable “Summary and Conclusions” (p. 1020) that “the claim for the presence in glucose of unfermentable reducing bodies as reversion products brought about by the action of the acids a t a high heat is untenable,” is thus contradicted by their own experiments. But the strangest perversion of the paper by Wesener and Teller upon “The Chemical Composition of Commercial Glucose and I t s Digestibility” is the one contained in the final word of the title, for in their long list of experiments they have not submitted a single one which has any bearing upon digestibility. To draw conclusions, as the authors have done, from fermentation experiments as to the digestibility of commercial glucose is hardly permissible. Indeed, if we assume the combined action of amylolytic enzymes and yeasts to correspond to the process of animal digestion, the only conclusion which can be drawn from Wesener and Teller’s experiments is that commercial glucose contains over I O per cent of indigestible matter. The authors employed diastase and pancreatin to help hydrolyze the carbohydrates of commercial glucose into fermentable sugars, yet the action of such enzymes, according to the authors’ own experiments, was far from complete. There always remained a considerable amount of unfermentable matter which, in the two experiments with malt diastase (p. 1013, Table 4), was 15.4 and 16.4 per cent and, in the experiments with pancreatin and taka-diastase (p. 1015, Table 9) was 15.3 and 9.5 per cent, respectively, of the original commercial glucose. I n order to make this unfermentable and hence apparently indigestible matter fermentable the authors boiled the filtered solution for two and one-half hours with 2 . 5 per cent hydrochloric acid and then, after neutralizing, fermented again with yeast. The question naturally suggests itself, if the combined action of diastatic enzymes and yeasts be accepted as indicative of digestibility, what operation in the digestive tract of the animal corresponds t o the treatment with boiling 2 . 5 per cent hydrochloric acid? The percentage of hydrochloric acid in the gastric juice of man is less than 0.5 per cent, while the temperature of the human stomach is over 60 centigrade degrees below the boiling point. The authors state (p. 1013) that the heating with 2.5 per cent hydrochloric acid was performed “in the usual manner, followed in determining starch.” The method of Sacchse, however, is an analytical and not a physiological process, and the results obtained by this method are no more an indication 1 Wohl, f
Ber., 1890, 2084. Ost, Chem. Ztg.. 19, 1.501.
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of digestibility than the conversion of cellulose into fermentable dextrose is an indication of the digestibility of sawdust. I n the final paragraph of the detachable “Summary and Conclusions,” Wesener and Teller make the following statement: “The fact that commercial glucose, when it is treated with diastase and then subjected to yeast fermentation, is almost wholly converted into alcohol and carbon dioxide, goes to prove that it consists of products that are wholly assimilable.” But according to the authors’ experiments “commercial glucose when it is treated with diastase and then subjected to yeast fermentation” leaves an unfermentable residue of over I O per cent. If commercial “glucose from such results be considered to be “almost wholly converted” then, by a simple use of the already familiar diminuendo, we may, perhaps, arrive a t the conclusion “that it consists of products that are zlholly assimilable.” I n a paper professing to deal with the digestibility of commercial glucose it is strange that no mention was made of the results obtained by feeding commercial glucose to bees. Some years ago commercial glucose was advertised extensively for the winter feeding of bees, but the experience of bee-keepers with this new substitute for cane sugar was most unfortunate. If attempts were made t o coerce the bees, by withholding other supplies of food, they would feed upon the glucose, but would then sicken and die. Experiments conducted by the U. S. Department of Entomology, upon the digestibility of various sugars by bees, also showed that bees would sicken and die of dysentery if restricted to a diet of commercial glucose. The conclusion of Wesener and Teller that when used as a food commercial glucose “pound for pound of dry weight will furnish at least as much energy as does cane sugar,” is accordingly contradicted by their own experiments. The combined action of diastatic enzymes and yeast, without the outside help of boiling hydrochloric acid, was able t o ferment cane sugar almost completely, yet under similar conditions was able to ferment only between 80 and 90 per cent of the dry solids of commercial glucose. What enzymes and yeast do not ferment and what honey bees reject may possibly be completely assimilated in the digestive tract of man, but most food chemists will retain their doubts upon this point until more conclusive experiments than those of Wesener and Teller are forthcoming. THE NEW YORKSUGAR TRADELABORATORY c . A BROWNE 80
ST., NEW June 8, 1917
SOUTH
YORK
A REPLY TO THE ABOVE “REJOINDER” Manuscript of a rejoinder by C. A. Browne to our paper “The Chemical Composition of Commercial Glucose and Its Digestibility,” which appeared in THIS JOURNAL, November, 1916, is before us for reply. With reference t o C. A. Browne’s statement of our appearing before the Illinois State Food Standards Commission, June, 1916, and reading a brief on “The Chemical Composition of Commercial Glucose and Its Digestibility” we beg to state that this is correct. A t that time we had finished our work, and as many witnesses appeared before the Illinois State Food Standards Commission, we confined our brief almost entirely to the conclusion of our article. The American Food Journal published the proceedings, for the most part, in detail. Then when our the American article was finally published in THISJOURNAL, Food Journal again made it a point to review our article and publish a n extract of it. REPLY TO CRITICISMS
I-Our critic endeavors t o put it forth as a fault that the body of our somewhat lengthy paper and detailed report of investigations is accompanied by a brief, comprehensive and readable summary of work done and conclusions indicated by same. 2-He criticises and later attempts to ridicule our statement that “ I n this respect, glucose, pound for pound of dry weight will furnish a t least as much energy as does cane sugar.”
