THE HYDROLYSIS OF SUCROSE BY THE 
 GASTRIC JUICE 
 
 BY 
 
 ROBERT McCLAUGHRY HILL 
 B. S., Carthage College, 
 1915 
 
 THESIS 
 
 Submitted in Partial Fulfillment of the Requirements for the 
 
 Degree of 
 
 MASTER OF SCIENCE 
 IN CHEMISTRY 
 
 IN 
 
 THE GRADUATE SCHOOL 
 
 OF THE 
 
 UNIVERSITY OF ILLINOIS 
 
 1921 
 
Digitized by the Internet Archive 
 in 2015 
 
 https://archive.org/details/hydrolysisofsucrOOhill 
 
YVs*^ 
 
 UNIVERSITY OF ILLINOIS 
 
 THE GRADUATE SCHOOL 
 
 Hay 24 , I 92 l_ 
 
 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY 
 SUPERVI SION BY Robert McQlaughry Hi 1JL 
 
 ENTITLED T he Rvd rol ysis of Sucrose by the Gastric ju lo e» 
 
 BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR 
 
 THE DEGREE OF 
 
 Master of Scienoe 
 
 
 In Charge of Thesis 
 
 Head of Department 
 
 Recommendation concurred in 
 
 
 Committee 
 
 on 
 
 Final Examination* 
 
 *Required for doctor’s degree but not for master’s 
 
 4 
 
 o <rj> 
 
 c'C 
 

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INDEX 
 
 Page 
 
 I. 
 
 Introduction . 
 
 
 1 
 
 II. 
 
 Methods. 
 
 
 
 5 
 
 III. 
 
 The Action 
 on Sucrose 
 
 of 
 
 in 
 
 Hydrochloric Acid 
 Vitro. 
 
 6 
 
 IV. 
 
 The Action 
 on Sucrose 
 
 of 
 
 in 
 
 Gastric Juice 
 Vivo. 
 
 7 
 
 V. 
 
 The Action 
 on Sucrose 
 
 of 
 
 in 
 
 Gastric Juice 
 Vitro. 
 
 10 
 
 VI. 
 
 The Retention of Glucose and 
 Sucrose in the Stomach. 
 
 12 
 
 VII. 
 
 Summary. 
 
 
 
 14 
 
 
 Bibliography. 
 
 
 15 
 
 
 Tables. 
 
 
 
 17 
 

 
 
 
 
 
 
 
 
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 ' 
 
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I, Introduction. 
 
 The question of the opportunity for and extent 
 of hydrolysis of cane sugar in the stomach normally is 
 still an open one. While it is generally conceded that the 
 acidity of the gastric juice is sufficiently high to permit 
 of a considerable degree of hydrolysis over a prolonged per- 
 iod of time, the actual extent to which this acid hydrolysis 
 may proceed under normal conditions of diet in man has 
 never been the subject of careful experimental study. Such 
 a study has been attempted in the present instance. 
 
 Robner (l) in 1859 and Claude Bernard (2) stated 
 that gastric juice had the power of inverting cane sugar. 
 Experiments carried out by Hoppe-Seyler (3) in 1856 and 
 
 n . . 
 
 Kuiz (4) 1874 indicate that the gastric juice has no such 
 power when the sugar is fed in moderate quantities. Hoppe — 
 Seyler, however, found appreciable inversion when large 
 quantities of sugar were fed. In 1887 Seegan (5) carried 
 out sugar feeding experiments on dogs. The dog9 were fed 
 100 g. of cane sugar daily for from 7 to 8 days and at the 
 end of that period were killed and examinations made of the 
 contents of the stomach and duodenum. Since glucose was 
 found in the stomach and no sucrose was found in the duo- 
 denum, Seegan came to the conclusion that sucrose is com- 
 pletely inverted in the stomach. Three years later, Voit 
 (6) carried out very similar experiments with rabbits, to 
 which were administered 30 g. of suorose. Six and a half 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
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3 
 
 hours later they were killed and examinations made of the 
 different portions of the alimentary tract. Analysis showed 
 that of the 3Ugar remaining in the stomach 90$ was hydrolyz- 
 ed and only 3 mg. of sucrose in the duodenum, an amount 
 thought to he within the experimental error of the methods 
 employed. The conclusion drawn wa3 the same as that of 
 Seegan, that inversion was practically completed in the 
 stomach. Voit was able, however, to recover from the entire 
 alimentary tract only 16$ of the sucrose fed. In consider- 
 ation of this fact and of the short time that carbohydrates 
 are now known to remain in the stomach, it seems that the 
 evidence on which the conclusion is based is insufficient. 
 
 In 1898 Ferris and Lusk (7) carried out a series of hydrolysis 
 experiments, in vitro, with 1$ to 5$ of sucrose solutions to 
 see whether the normal gastric concentration of hydrochloric 
 acid (0.3-0, 3$) was sufficient to account for the inversion 
 found in Voit* 3 experiments. While the inversion in 6.5 
 hours wa3 10$ to 30$ lower than that found by Voit in rab- 
 bits, they concluded that the inversion in the stomach could 
 be completely accounted for by the concentration of free 
 acid. In 1902 Widdicombe (8) reported the presence of an 
 active sucrase in the gastric juice of dogs and pigs, but 
 Lusk (9) in 1904 repeated these experiments and was unable 
 to corroborate his findings. 
 
 In regard to the action of gastric juice on sucrose 
 the statements in the current textbooks are very contradictory. 
 Some of the authors recognize the unsettled state of the 
 
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 question but others make positive statements, - hardly just- 
 ified by our present knowledge - the contradictory nature of 
 which has given rise to considerable confusion. The follow- 
 ing quotations illustrate the widely varying treatment of the 
 subject: " — the hydrolysis of the carbohydrates of the food 
 may be continued, to some extent at least, by the hydrochloric 
 acid of the stomach. This chemical hydrolysis, however, if 
 it occurs, is of less importance than the action of the gastric 
 enzymes upon proteins, milk and fats.” (Bainbridge and Menzies 
 (10)). "While proteids are practically the only nutrients 
 digested in the stomach, it is also true that none of the 
 
 preparatory actions on other nutrients take place here. 
 
 Sugar and certain salts may also be dissolved here by the 
 water and acid of the gastric juice." (Eddy (11)). "Gastric 
 juice has no direct action on carbohydrates." (Huxley (is)). 
 
 In contrast to these we have --"By the action of the hydro- 
 chloric acid (of the gastric juice) certain changes are in- 
 duced in the food stuffs. Cane sugar is inverted to glucose 
 and fructose." (Starling (13)). "It (gastric juice) inverts 
 cans sugar into glucose and fructose." (Halliburton (14)). 
 According to Mathews (15) "To what extent cane sugar is in- 
 verted in the stomach will depend on the length of time it 
 remains there after free acid appears. This time is normally 
 so short that probably little inversion occurs, " and Hammer- 
 sten (IS) "The statements in regard to the ability of gastric 
 juice to invert cane sugar are very contradictory. At least 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
this action of the gastric juice is not constant, and if it is 
 present at all it is probably due to the action of acid. " 
 
 Those who have held that the hydrochloric acid of 
 the gastric juice was the active agent in the hydrolysis of 
 sucrose in the stomach have based their belief on experiments 
 carried out in vitro with sucrose in acid solutions of the 
 strength assumed to be present in the stomach. Based on this 
 assumption the inversion could not be very great if the 3hort 
 time that sucrose remains in the stomach under normal conditions 
 is considered. Those who have believed that there are other 
 factors concerned have argued that on postmortem examinations 
 after sucrose feeding, sucrose and reducing sugar are found 
 in the stomach whereas only invert sugar is found in the 
 duodenum. Thi3 seemed to prove that the sucrose was all hydro- 
 lyzed before it passed the pylorus. 
 
 All of our knowledge of the extent of inversion of 
 sucrose in the stomach has been obtained from hydrolysis by 
 hydrochloric acid in vitro and from postmortem examinations 
 after sucrose feeding. At best the results of such postmortem 
 examinations are very doubtful indices of the actual physio- 
 logical processes under normal conditions. For these reasons 
 it was thought that it would be profitable to carry out a 
 series of direct experiments on the inversion of sucrose in 
 
 the human stomach. The Rehfuss stomach tube makes such an 
 
 » ?* 
 
 examination especially feasible, not only because the exam- 
 ination is made under normal conditions of digestion, but 
 because it is possible to follow the course of the inversion 
 by making use of the "fractional" method of analysis. 
 

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 - 5 - 
 
 II. Methods. 
 
 The Benedict -Osterberg (17) modification of the 
 Benedict blood sugar method was used for the determination of 
 the glucose in these experiments. The picric acid employed 
 was purified according to the procedure of Folin and Doisy (18). 
 Picramic acid purified by the method of Egerer (19) was used 
 as the color standard. The sucrose used in these experiments 
 was purified from the best commercial granulated sugar. The 
 method of purification wa3 the following: A thick syrup was 
 
 made by dissolving the sugar in water which, to avoid any 
 hydrolysis, was not heated. The syrup wa3 then poured slowly 
 into 95 $ alcohol from which sucrose precipitated out in very 
 fine crystals. A second precipitation was made and the sugar 
 then dried with suction on a Buchner funnel and finally in a 
 vacuum desiccator. The sucrose purified in this way which we 
 used in our experiments when tested in the polar imeter showed 
 a purity of 99.98$. 
 
 The possibility was suggested that the picrate- 
 picric acid reagent might invert some of the sucrose and thus 
 cause high results. To test this, known amounts of sucrose 
 were added to a standard solution of glucose containing one 
 mg. of glucose in 4.0 cc. The glucose was then determined 
 in the solutions made up in the same way. The results given in 
 Table I show that the glucose content is not altered by the 
 presence of sucrose and that the picrate-picric acid reagent 
 does not invert any of the sucrose present. 
 

 
 
 
 
 
 
 
 
 
 
 
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- 6 - 
 
 III. The Action of Hydrochloric Acid 
 on Sucrose in Vitro. 
 
 In order to determine to what extent hydrochloric 
 acid in the concentrations found in gastric juice would invert 
 sucrose, hydrolysis experiments in vitro were run. Ferris and 
 Lusk (7) have carried out such determinations. We repeated 
 these experiments using essentially the same procedure, the 
 details of which are indicated in Table II. Erlenmeyer flasks 
 containing 2Q.0 cc, of 0.5 $ and 1.0$ sucrose solution with 
 the desired hydrochloric acid concentration were incubated for 
 two hours at 37° C. and samples withdrawn at stated intervals 
 for analysis. The samples were immediately neutralized exactly 
 to methyl red-methyl blue, made up to definite volume, and 
 the glucose determined in aliquots. The results of these analyses 
 are shown in Table II. Our figures agree in general with the 
 results of similar experiments of Ferris and Lusk (7), following, 
 as they point out, Wilhelmy* s law of chemical change. As the 
 action of the acid continues, the concentration of the sucrose 
 decreases so that the rate of the reaction becomes les3 a3 it 
 proceeds. In the case of the 1.0$ sucrose in 0.7$ hydrochloric 
 acid if the rats of the reaction remained the same the inversion 
 would be 8,4$ at the end of one hour and IS. 8$ at the end of 
 two. Actually the inversion at the end of these periods is 
 8.3$ and 15.3$ showing the progressive decrease in the rate of 
 inversion. 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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7 
 
 IV. The Action of Gastric Juice on Sucrose 
 
 in Vivo. 
 
 The general procedure used by Okey (30) in her invest- 
 igation of the hydrolysis of inulin in the stomach wa3 followed 
 in these experiments. The subjects were healthy men and women, 
 students in the laboratory. The experiments were carried out 
 on the fasting subject, no food having been consumed since the 
 evening meal of the previous day. In the earlier experiments 
 a "meal” was given consisting of the whites of three eggs 
 cooked "soft". As an experiment (Table III) carried out with 
 the egg white meal without sucrose showed that the egg white 
 contained an appreciable amount of glucose, for which corrections 
 had to be made, in the later experiments 50 g. of cottage 
 cheese were used as the test meal. The cottage cheese was 
 repeatedly triturated with water (7-10 times) and drained 
 through cheesecloth until 5 cc. of the wash water gave no 
 appreciable reduction with 10 cc. of Fehling* s Solution. About 
 fifteen minutes after the meal was eaten the stomach tube was 
 taken, and after five minutes 5.0 g. of sucrose in 150 cc. of 
 distilled water were given through the tube and the tube rinsed 
 with 50 cc. of distilled water. In the later experiments lOOcc. 
 of the distilled water were given before the sucrose and after 
 five minutes a sample withdrawn to test for reducing substances. 
 After the introduction of the sugar, three samples were removed 
 at twenty minute intervals for examination. The "free" and 
 "total" acid were titrated against standard sodium hydroxide 
 using diraethylaminoazobenzene and phenolphthalein as indicators. 
 

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An aliquot was neutralized, immediately and the protein precip- 
 itated by adding the picrate-picric acid reagent with which 
 it was made to 25 cc. The glucose was then determined by the 
 Benedict -Osterberg modification of the Benedict method. These 
 results represent the amount of reducing sugar present due to 
 the normal action of the gastric juice. A second aliquot was 
 incubated at 37° C. for two hours and the reducing sugar deter- 
 mined in the same way. The results in this case showed the 
 amount of inversion possible if the normal gastric juice 
 were afforded the opportunity for prolonged action on the suc- 
 rose. To a third portion hydrochloric acid was added to give 
 a final concentration of 1.0 °]o hydrochloric acid and the mix- 
 ture was hydrolyzed by boiling for one hour. The boiling in 
 acid solution should completely invert the sucrose and the 
 subsequent determination of the reducing sugar would then show 
 the total carbohydrate, sucrose plus invert sugar, present. 
 Since regurgitation from the intestine, at intervals, is now 
 known to accompany gastric digestion normally, it was thought 
 that the sucrase of the intestinal juice might have an appreci- 
 able effect in inverting sucrose in the stomach. To test 
 this a sample was withdrawn from the stomach before the sucrose 
 was introduced, and neutralized. Sucrose was added and the 
 mixture incubated for two hours. Any hydrolysis in this test 
 would indicate the presence of sucrase since other hydrolyzing 
 factors were eliminated. In none of these was there any 
 hydrolysis, showing the absence of active sucrase. 
 

 
 
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- 9 - 
 
 Five experiments were carried out with the egg-white 
 meal and three with the cottage cheese. In all seven subjects 
 were studied. Early in the experiments where the egg-white 
 meal was ingested (Table IV) there is apparently a considerable 
 hydrolysis which the free acid present cannot completely 
 account for. However, when these figures are corrected for the 
 glucose content of the egg-white (Table III) the hydrolysis 
 represented by the corrected figure can be easily accounted 
 for by the free acid concentration. This corrected figure also 
 correspond very closely to that obtained with the cottage 
 cheese meal which contained only a negligable amount of glucose. 
 After two hours incubation there is obtained a hydrolysis closely 
 parallel with the hydrolysis due to hydrochloric acid alone 
 in similar concentrations as shown in the experiments recorded 
 in Table II, The total sugar present, as shown by the com- 
 pletely hydrolyzed samples, indicates that the sugar has 
 almost completely left the stomach at the end of one hour. Even 
 though the per cent of hydrolysis is comparatively large, it is 
 in reality of little consequence because of the small quantity 
 of sugar remaining in the stomach at that time. 
 
 These experiments show a slight hydrolysis of the 
 sucrose in the sample taken from the stomach twenty minutes 
 after ingestion and a small increase in the hydrolysis in the 
 samples taken later. The extent of hydrolysis in the stomach 
 can be of no practical importance because of the short time 
 the sugar remains there and in every case it can be almost 
 completely accounted for by the action of the free acid present. 
 

 
 
 
 
 
 
 
 
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- 10 - 
 
 V. The Action of Gastric Juice on Sucrose 
 
 in Vitro. 
 
 To confirm our findings in the feeding experiments 
 a series of tests were carried out on the action of gastric 
 juice on sucrose in vitro. The egg-white meal was fed in all of 
 these and only one sample of gastric juice was withdrawn. This 
 was removed 40 minutes after the meal which is the average time 
 of maximum acidity under the conditions of these experiments. 
 
 In one portion the acidity of the gastric juice was determined, 
 in a second reducing sugar was analyzed for. The latter figure 
 shows the amount of glucose in the gastric contents and was 
 used as a correction to he applied in the following inversion 
 tests. To each of four 10 cc. aliquots 50 mg. of sucrose were 
 added. The first portion was incubated two hours. This is 
 comparable with the similar tests in the feeding experiments, 
 and gave similar results as may be seen by comparing the fig- 
 ures obtained with the incubated samples in Tables IV, and V. 
 Since the attempt, described in Section IV, , to demonstrate 
 the activity of regurgitated intestinal sucrase in the stomach 
 did not give positive results, a further test was made. For 
 this purpose the second portion of gastric juice was heated to 
 boiling before any sucrose was added. On cooling, 50 mg. of 
 sucrose were added and it was then incubated for two hours. The 
 heating would kill any enzyme that might be present and the 
 inversion should be due solely to the free acid concent ra.t ion. 
 The third aliquot was not heated but was neutralized before the 
 addition of the sucrose and then incubated. If any inversion 
 

 
 
 
 
 
 
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- 11 - 
 
 occurred in this case it would necessarily be due to factors 
 other than the acidity and would indicate the presence of en- 
 zymes. The fourth aliquot was both boiled and neutralized 
 before the sucrose was added. This was run as a control and no 
 inversion would be expected. 
 
 Inspection of Table VI. shows that the results of this 
 series of experiments bear out the findings in the feeding 
 tests. Boiling the gastric juice without neutralization has 
 no effect on its power to invert sucrose while neutralization 
 alone completely takes away that power. This shows that no 
 enzyme action is concerned in the inversion and that the pre- 
 sence of free acid is necessary for it to take place. Com- 
 parison with the results recorded in Table II. show that the 
 inversion is practically identical with that in aqueous sol- 
 utions of the same hydrochloric acid concentration, and there- 
 fore that the free acid concentration of the gastric juice is 
 sufficient to explain all of the hydrolysis. of sucrose that 
 takes place in the stomach. These experiments further show 
 that if any sucrase is carried into the stomach by regurgitat ion 
 from the intestine it does not remain active long enough to 
 have any effect in the gastric hydrolysis of sucrose. 
 

 
 
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- 12 - 
 
 VI. The Retention of Glucose and. Sucrose in the Stomach. 
 
 During the course of our investigation the question 
 arose as to whether glucose and sucrose leave the stomach at 
 the same rate. If glucose leaves more rapidly than sucrose 
 it is evident that analysis of the gastric contents alone will 
 give figures that are too low for the per cent of inversion. 
 
 Five grams of glucose were given under the same conditions as 
 in the sucrose experiments and samples removed at twenty min- 
 ute intervals were neutralized immediately to methyl red — meth- 
 ylene blue. The glucose was then determined as in the previous 
 experiments. The results of this test are shown in Table VII. 
 
 In Table VIII the average speed of evacuation of sucrose from 
 the stomach in all the sucrose feeding experiments is compared 
 with the speed of evacuation of glucose. As a basis of com- 
 parison we have taken the analysis of 5 cc. aliquots of the 
 first sample, withdrawn twenty minutes after the meal was eaten. 
 The figures in the table show the percentage of sugar still 
 present in the stomach, after forty and sixty minutes, comput- 
 ed on this basis. The table also shows the free acidity of 
 the glucose feeding experiment compared with the average free 
 acidities of the sucrose experiments. The glucose appears to 
 be leaving the stomach more rapidly in the first period but 
 the free acidity in the case of the glucose is correspondingly 
 higher and this would lead us to expect a more rapid evacuation. 
 It is recognized that in these experiments very close agree- 
 ment cannot be expected because of the varying extent of dil- 
 
' 
 
 
 
 
 ■ 
 
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- 13 - 
 
 ution of the sugar solutions by the gastric juice, and further 
 since only one subject was studied the tendency to individual 
 variation must be considered. However, we believe that this 
 shows clearly that there is no material difference in the rate 
 at which glucose and sucrose leave the stomach under the 
 conditions of our experiment. 
 

 
- 14 - 
 
 VII. Summary. 
 
 (1) Hydrochloric acid of the strength normally 
 found in the stomach has the power of inverting sucrose in 
 appreciable quantities in from one to two hours. 
 
 (2) The inversion of sucrose in the human stomach 
 may be explained solely by the action of the hydrochloric 
 acid present. This inversion is too small to be of any 
 consequence in the short time that the sucrose remains in 
 the stomach. 
 
 (3) The inverting action of human gastric juice 
 
 in vitro is essentially the same as that of hydrochloric acid 
 solutions of the 3ame concentration. 
 
 (4) We were unable to demonstrate the presence 
 of any sucrase of either gastric or intestinal origin in 
 gastric juice. 
 
 (5) Sucrose and glucose leave the stomach at 
 essentially the 3ame ra.te. 
 

 
 
 
 
 
 
 
 
 
 ™ V w l : I . ppiMfr 
 
 
 
 
 
 
 
 
 
15 
 
 Bibliography. 
 
 (I) Robner, discuis de sacher cannae in tractu cibario 
 mutat ionibus, dis3. insug. Breslau 1859; cited by 
 Carl Voit, Zeit. f. Biologie, 1891, Vol. 38, p. 268. 
 
 (3) Bernard, Claude, Physiologie experimental, Paris, 
 
 1855 Vol II p. 402. 
 
 (3) Hoppe-Seyler, Felix, Virch. Arch. 1856 Vol. 10, p. 
 144. 
 
 (4) Killlz, E., Beitr. Z Path. u. Therapie des Diabetes 
 Mellitus, Marburg 1874, p. 147; cited by Carl Voit, 
 Zeit. f. Biologie, 1891, Vol. 38, p. 268. 
 
 (5) Seegan, J. , Archio. f. d. ges. Physiol. 1887, Vol. 
 40, p. 41. 
 
 (S) Voit, Carl, Zeitschr. f. Biologie, 1891, Vol. 38, 
 p. 3S8 . 
 
 (7) Ferris, S. J. and Lusk, Graham, Am. Jour, of Physiol 
 ogy, 1898, Vol. 1, p. 277. 
 
 (8) Widdicombe J. H. , Jour, of Physiology, 1903 Vol. 28, 
 p. 175. 
 
 (9) Lusk, Graham, Proc. of the Am. Physiol. Soc.,Am. 
 Jour, of Physiology 1904, Vol. 10, p. xxi. 
 
 (10) Bainbridge and Menzies, Essentials of Physiology, 
 Longmans, Green and Co. London, 1914, p. 302. 
 
 (II) Eddy, A Textbook in General Physiology and Anatomy, 
 American Book Company New York, 1907, p. 116. 
 
 (13) Huxley, Lessons in Elementary Physiology, The Mac- 
 millan Company, New York, 1918, p, 248. 
 

 
- 16 - 
 
 (13) 
 
 (14) 
 
 (15) 
 (IS) 
 
 (17) 
 
 (18) 
 
 (19) 
 
 (30) 
 
 Starling, Principles of Human Physiology, Lea and 
 Febiger, New York, 1912, p. 788. 
 
 Halliburton, Handbook of Physiology, 13th Edition, 
 P. Blaki3ton’ s Son and Co. Philadelphia, 1917, p. 
 
 513. 
 
 Mathews, Physiological Chemistry, William Wood and 
 Company, New York, 1916, p. 350. 
 
 Hammarsten, A Textbook of Physiological Chemistry, 
 John Wiley and Sons, New York, 1913, p. 449. 
 Benedict, S. R. and Osterberg, E.,J. B, C., 1918, 
 Vol. 34, p. 195. 
 
 Folin, Otto and Doisy, F. A., J. B. C., 1916, Vol. 
 
 28, p. 349. 
 
 Egerer, Grete, J. B. C., 
 
 1918, Vol. 35, 
 
 Okey, Ruth, J, B. C., 
 
 1919, Vol. 39, p. 
 
 p. 565. 
 149. 
 
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26 
 
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 The Rate of Evacuation of the Stomach. 
 Comparison of Glucose and Sucrose. 
 
 Time After 
 
 Ingestion. Free Acidity * 
 cc.N/10 acid 
 
 Per cent Remaining in Stomach 
 
 
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 26 
 
 * The amount of carbohydrate 
 
 present 
 
 at the end of twenty rain- 
 
 utes is taken as a basis for the calculation of the per cent of 
 sugar remaining in the stomach in the later periods. 
 
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