Class JZli d^-tJ- >a/ it Book. >-y cy _ Copiglit]^'- COC^RIGHT DEPOSIT. WORKS OF ANDREW L. WINTON. PUBLISHED BY JOHN WILEY & SONS, Inc. A Short Course in Food Analysis. ix + 252 pages, 6 by 9, 107 figures. Cloth. $1.50 net. The Microscopy of Vegetable Foods. With Special Reference to the Detection of Adul- teration and the Diagnosis of Mixtures. By Andrew L. Winton, Ph.D., with the Collabora- tion of Dr. Josef Moeller, Professor of Pharmacognosy, and Head of the Pharmacognos- tical Institute of the University of Vienna, and Kate Barber Winton, Ph.D. xiv +701 pages, 6f by 10, 635 figures. Cloth, $6.50 net. Translation: The Microscopy of Technical Products, By Dr. T. F. Hanausek. Revised by the author and translated by Andrew L. Winton, Ph.D., with the collaboration of Kate Barber Winton, Ph.D. xii+471 pages , 6i by 10, 276 figures. Cloth, $5.00 net. Revision: Food Inspection and Analysis. By Albert E. Leach, S.B.,Late Chief of the U. S. Food and Drug Laboratory at Denver. Revised and enlarged by Andrew L. Winton, Ph.D. xxi + 1001 pages, 61 by 10, 120 figures, 40 full-page half-tone plates. Cloth, $6.50 net. A COURSE IN FOOD ANALYSIS BY ANDREW L; WINTON, Ph.D. AUTHOR OF THE MICROSCOPY OF VEGETABLE FOODS; REVISER OF leach's FOOD INSPECTION AND ANALYSIS; TRANSLATOR OF HANAUSEK'S microscopy of TECHNICAL PRODUCTS FIRST EDITION NEW YORK JOHN WILEY & SONS, Inc. London: CHAPMAN & HALL, Limited 1917 -T^ Copyright, 1917 BY ANDREW L. WINTON / MAY 10 1917 pRtBS or BRAUNWORTH II CO. BOOK MANUFACTUnERI BROOKLYN. N. Y. /S'a n^ .. / PREFACE The purpose of this book is first to start the chemical student on the right road to the intelligent use of more extensive works and thereby become a professional food analyst, and second, to meet the needs of the general student who takes up food analysis partly for mental and manual discipline and partly because of its bearing on subjects such as agriculture, food manufacture, nutrition, and household economics. Although the detailed instructions may seem more adapted to the wants of the student of the second class, whose training may have been limited to class room and laboratory work in general chemistry, it is believed that no one will find them too explicit. The fact that a course in quahtative analysis requires a full semester of laboratory work and an abridged course in quanti- tative analysis another semester deters many who would other- wise avail themselves of the excellent systematic training these subjects afford. Such students may find that an introductory course in food analysis, requiring but forty laboratory periods such as this book contemplates, furnishes not only the requisite discipline, but also a general insight into the composition and microscopic structure of products needed in everyday life. While inorganic methods have a certain degree of sameness, being largely based on precipitation or titration, the methods of food analysis include extraction, polarimetric, colorimetric, centrifugal, and distillation? processes, thus furnishing training in versatility. Although the methods selected are but a few of those in the Hterature, they are the ones most generally used and least Uable to become obsolete through change in trade practices or official rulings. After they have been thoroughly -aN iv PREFACE mastered the analyst should be able to undertake at once the bulk of the work of most food laboratories. In order that he may have a clear conception of the whole subject and be able to use intelHgently the literature, the principles of other impor- tant methods are briefly considered. As some of the apparatus is not ordinarily found in the analytical laboratory care has been taken in describing it so that it can be accurately specified in ordering from the dealer. Lists of apparatus, reagents, and materials for analysis, required for the course, are given in the appendix. While the chapters are arranged in their logical sequence, thus seeking gradually to develop the subject and bring out clearly general principles, a rigid adherence to this order by all the members of a large class would necessitate the duplication of expensive apparatus. To meet this difficulty the matter has been so arranged that it can be divided into five sections, each of which can be assigned to a group of six students, and thus one saccharimeter, one refractometer, one Westphal balance, one tintometer, one calorimeter, one polarizing microscope, six ordinary microscopes, and certain pieces of multiple apparatus be made to do duty for a class of thirty students. Although the laboratory work may seem at first sight more than can be carried out in the time allowed, the author knows from experience that with reasonable diligence on the part of the student it can be accomplished in a satisfactory manner pro- vided he is not called upon to prepare reagents or standardize solutions. As an example in ethics too often neglected, if for no other reason, care has been taken in describing methods to give the names of authors and original references, although unnecessary foot notes have been avoided. Analyses of typical foods have been drawn from the compilations of Atwater and Bryant, Doane and Lawson, Farrington and Woll, Jenkins and Winton, and Koenig, also from the bulletins of Frear, Given, and Broomell, Merrill and Mansfield, and others. The constants of fats and oils are largely those given by Lewkowitsch. PREFACE V Grateful acknowledgment is also due the author's friends Dr. C. A. Browne, Prof. E. M. Chamot, Prof. T. F. Hanausek, Prof. Josef Moeller, and others for the use of cuts. Free use has been made of matter in Leach's Food Inspection and Analysis, both that inserted by Mr. Leach during his lifetime and by the author in his revisions. The efforts of friends are thus again joined in the same cause. Wilton, Conn., March, 191 7. CONTENTS The star designates sections devoted -to laboratory work. CHAPTER I PAGE Introduction 1-9 Foods: Animal, i; Vegetable, 2; Mineral, 4; Calories, 4. Food Analysis: Province; Limitations; Literature, 5; Laboratory Worli, 7; Division of Class, 8. CHAPTER II Dairy Products ". . . .11-31 Milk: Composition, II ; Colostrum; Value; Standards, 12; Sampling, 13; *Practice Material; * Specific Gravity, 14; Solids, *Dish Method, 15; *Asbestos Method, 16; Fat; *Babcock Test, 18; * Formaldehyde, 20; *Ether Extraction, 21; *Calcula ted Solids; * Boric Acid; Protein; Lactose, 25. Butter: Composition; *Preparation of Sample, 26; *Water; *Fat; *Curd; *Ash, 27; Gooch Crucible, 28. Cheese: Composition, 29; Analysis, 30. Condensed Milk : Analysis, 30. Ice Cream, 30; Analysis, 31- CHAPTER III Meat and Fish 33-40 Meat, Fish, and Eggs: Constituents, S3', Composition, 34. Meat Extracts, 34. Preservatives, 36. *SidpIiur Dioxide, 38. CHAPTER IV Natural Vegetable Foods and Mill Products 41-81 Groups of Constituents, 41; Criticism of Methods; *Practice Material, 42. Composition: Cereals; Legumes; Oil-seeds, 44; Vegetables; Fruits; Nuts, 45; Spices, 46. Sample: *Drawing, 46; *Preparation, 48; *Care of, 49. Moisture: Variation; Consideration of Methods, 50; ♦Drying in Hydrogen, 52; Method for Spices, 55. Fat: Constituents, 55; Principles of Methods; *Ether Extraction, 56; Method for Spices, 59. Crude Fiber: Nature, 59; *Henneberg Method, 60. Protein: Nature, 63; *Kjeldahl Method, 65; Standard Acid and Alkali, 70; Gunning- Arnold Modification, 72. Ash: Constituents, 72; *Method, 73. *Nitro- gen-free Extract, 74. Starch: Chemical Properties, 74; *Method, 75. vii viii CONTENTS Pentosans, 77. Flour: Testing, 77. Yeast, 78. Baking Powder: Constituents, 78; Reactions; *Practice Material, 79; Tests for *Sul- phalcs; * Phosphates; *Almnimim Salts, 80; *Starch, 8i. CHAPTER V Microscopic Examination of Vegetable Foods 83-125 Introduction: Province, 8.3; Microscope, 84; Microscopic Accesso- ries, 85; *Calibration of Micrometer, 86; Mounting, 87; Observation, 88. Microscopy of Starches: Nature of Starch Grains, 88; *Wheat Starch; *Oat Starch; *Bean Starch; *Com Starch; *Potato Starch; *Cassava Starch, 92. Typical Foods: *Practice Material, 93; *Wheat, 04; *Rye, 99; *Oats, 100; *Corn, loi; *Buckwheat, 103; *Peas, 105; *Cotton Seed, 106; *Flax Seed, no; *Black Pepper, 112; *Cayenne Pepper, 114; *Cinnamon, 115; *Ginger, 116; *CoflEee, 118; *Cocoa, 120; *Tea, 122. *Mixtures, 122. CHAPTER VI Saccharine Products 127-138 Sugar: Characters, 127; Saccharimeter, 128; * Polarization, 130. Molasses, S3Tups, and Honey: Composition; *Practice Material, 133; *Sucrose by Polarization, 134; '''Solids by Refraction, 135. Maple Prod- ucts, 135. Fruit Syrups: Artificial Colors; *Practice Material, 136; *Wool Test, 137; *Cochineal Test, 138. CHAPTER VII Fats and Oils 139-161 Constitution; Oxidation and Halogen Addition, 139; Saponification, 140; SolubiUty and Volatility of Fatty Acids, 141. Edible Fats and Oils: Constants, 141; *Practice Material, 142; *Spccific Gravity with Westphal Balance, 144; ^Refractive Index; Refractometer, 146; *Hal- phen Reaction, 150; *Baiidouin Reaction, 151; *Iodine Number, 152; '''Saponification Numb r, 155; ''''Volatile Fatty Acids, 157; Polenske Number; Other Constants, 159; Hydrogenation, 161. CHAPTER VIII Fruits, Fruit Products, Liquors, and Vinegars 163-178 Constituents: Sugars; Acids, 163; Starch; Oil; Fiber; Alcohol; Solids, 164; *Practice Material. 165. Fruit Juices: '^Solids, 166; '''Sugar, 167; '''Acidity, 168. Wine, Cider, and Other Liquors: Fermen- tation, 168; Analysis, 170; Composition, 171; *Alcohol, 172; '''Solids; * Acidity, 174. Vinegar: Kinds, 174; Manufacture, 175; Composition, 176; *Solids; *Acidity, 177. Various Fruit Products: Analysis, 177; Preservatives, 177. CONTENTS ix CHAPTER IX PAGE Flavoring Extracts 179-201 Spices vs. Extracts, 179; Nature of Methods, 180. Vanilla Extract and Substitutes : Vanilla Beans, 180; Faw///?w; Tonka Beans; Coiimarin; Vanilla Extract, 181; Substitutes; *Practice Material, 183; *Hess and Prescott Vanillin and Coumarin Method, 184; *Coumarin Melting-point, 188; *Leach Coumarin Test; Tintometer; *Color Values, 189; *Normal Lead Number, 191; *Folin and Denis Colorimetric Vanillin Method, 192; Colorimeter, 193; Other Constituents, 196. Lemon Extract: Lemon Oil, 196; Terpeneless Lemon Extract; *Practice Material, 197; Lemon Oil, ^Centrifugal Method; *Polariscopic Method; *Citral, 198; Other Con- stituents, 200. Orange, Almond, Wintergreen, Peppermint, and Spice Extracts, 200. CHAPTER X Coffee, Tea, and Cocoa 203-210 Food Value; Stimulating Principles; Caffeine; Theobromine; 203; Microscopic Structure, 204. Coffee: Composition, 204; Substitutes; *Gorter Caffeine Method, 205; Other Constituents, 206. Tea: Composi- tion; Coloring; Facing, 207; Foreign Leaves; Spent Leaves; Analysis, 208. Chocolate and Cocoa: Composition, 209; Analysis^ 210. APPENDIX Calculation Tables 211-230 Temperature Correction of Lactometer Readings, 211. Calculation of Total Solids of Milk from Lactometer Reading and Fat, 212. Cal- culation of Sugars from Cuprous Oxide, 213. Equivalents of Refractom- eter Readings, 222. Calculation of Dry Substance from Refractive Index, 224. Temperature Correction for Preceding, 225. Calculation of Alcohol from Specific Gravity, 226. Lists 231-238 Apparatus, 231. Reagents, 235. Practice Material, 237. A COURSE IN FOOD ANALYSIS CHAPTER I INTRODUCTION Foods are classified as animal, vegetable, and mineral, and are divided into subgroups according to their source or method of manufacture, factors which are intimately correlated with their chemical composition. Animal Foods. The Natural Animal Foods include milk, eggs, meat, and fish. All of these contain (i) Water, or moisture, (2) Crude Fat (or more correctly Ether Extract), (3) Protein (nitrogenous substances such as casein of milk, albumin of eggs, and myosin of meat), (4) Ash, or mineral matter (chiefly sodium, potassium, calcium, magnesium, and iron, combined as phos- phates, sulphates, chlorides, and carbonates or in organic com- binations), and (5) Carbohydrates (lactose of milk, glycogen of meat, etc.). Except in a few foods such as milk and liver, the amount of carbohydrates is so small that for ordinary purposes it is negligible. Minor constituents, such as Citric Acid of milk. Lecithin (phosphorized fat) of eggs. Zoosterols (cholesterol, etc.) of fats. Creatine, Creatinine, and Xanthine Bases of meat, although of great interest to the physiological chemist, are of comparatively small importance to the food analyst engaged in nutrition or inspection work. Manufactured Animal Foods. Of the dairy products, cream is milk with extra fat, cheese is milk with most of the lactose (milk sugar), the albumin (soluble protein), and part of the water and mineral matter eliminated and salt added, and butter 2 INTRODUCTION is the fat of milk with some water, a trace of casein and mineral matter, and added salt. Eggs are usually bought for the con- sumer in the shell, although the shell contents, dried or frozen, and egg albumin are prepared in considerable amount from the cracked and otherwise damaged eggs which accumulate at shipping centers. Meat products include sausage and other minced foods, lard and edible tallow, which for convenience are usually treated in connection with vegetable fats and oils, gela- tin, a substance related to the proteins obtained from hoofs, hides, etc., and meat extracts consisting in large part of flavoring and stimulating substances. Fish products are relatively unim- portant. Salt and wood smoke are time-honored preservatives for meat and fish. Chemical preservatives (formaldehyde, borax, boracic acid, sulphites, and sodium benzoate) of late years, have come into use, not only in meat and fish, but also in milk and dairy products. Artificial colors and in the case of canned goods metallic contamination are also met with. Vegetable Foods. The Natural Vegetable Foods are classi- fied as cereals, leguminous seeds, oil seeds, nuts, vegetables, fruits, spices, and alkaloidal products (tea, coffee, and cocoa). The constituents of these are divided into six groups: (i) Water, (2) Crude Fat (ether-extract), (3) Crude Fiber (cellulose, lignin, etc.), (4) Crude Protein, (5) Ash, and (6) Nitrogen-free Extract (starch, sugars, gums, organic acids, etc.). All the groups but the third are common to both animal and vegetable foods although the nitrogen-free extract, which forms the bulk of the cereals, leguminous seeds, and many other vegetable foods, is a minor constituent of most animal foods excepting milk. The third group, crude fiber, is characteristic of vegetable organ- isms. It forms the frame work of vegetable cells consisting in the young or active tissues of Cellulose and in hardened or woody parts of cellulose and " infiltrated " substances such as Lignin (woody substance), Suberin (cork substance), Cutin (cuticle substance), etc. More or less satisfactory methods are available for the deter- mination of certain of the individual compounds present in each INTRODUCTION 3 of the six groups as, for example, the different acids and bases of the ash, the individual proteins and the Amido Compounds of the crude protein, the volatile and non- volatile acids, the non-saponifiable matter, including Phytosterols (sitosterol, etc.) of the ether extract, and the Starch, Sugars, Pentosans, Dextrin, and Organic Acids of the nitrogen-free extract. Some of the most important of these methods are described in the chapters which follow. Spices contain all the six groups of substances enumerated but are valuable only for certain Essential Oils or other flavoring constituents. Although soluble in ether essential oils are not grouped with the fixed (non- volatile) or fatty oils. Being vola- tile they pass off with the water on heating, although more slowly. Alkaloidal foods, unlike spices, are valuable partly for their flavoring constituents but chiefly for their stimulating principles, Caffeine and Theobromine, which like essential oils can be quan- titatively determined. Manufactured Vegetable Foods are grouped as (i) cereal products (flour, meal, and other mill products), (2) leguminous products (pea meal and peanut butter), (3) oil cakes (cotton seed, linseed, and other cakes used chiefly as cattle foods), (4) vegetable products (pickles, catsup, and canned vege- tables), (5) fruit products (jams, jeUies, fruit juices, dried and canned fruits), (6) oils and fats, (7) saccharine products (sugar, syrup, honey, and confectionery), (8) alcoholic hquors (fruit juices, cereal extracts, or other saccharine liquids which have been fermented and in certain cases distilled), (9) vinegars (alcoholic liquors subjected to acetous fermentation, whereby alcohol oxidizes to acetic acid), and (10) flavoring extracts (alco- holic solutions of essential oils and other substances). In the cereal, leguminous, oil seed, vegetable, and certain fruit products determinations of the six groups of constitu- ents already dwelt on are of chief importance; in oils and fats the so-called chemical and physical constants, including Iodine Number, Saponification Number, Volatile Fatty Acids, Specific Gravity, Refraction, etc., are determined for purposes 4 INTRODUCTION of identification; in saccharine products determinations of sugars are made by polariscopic and chemical methods; in alcoholic liquors and vinegars Alcohol and Acetic Acid respect- ively are most often estimated; and in flavoring extracts the amounts of essential oil, Vanillin, or other aromatic constitu- ents are of importance. In addition to the chief constituents certain others of minor importance are often determined solely as a means of detecting foreign admixture. Added colors, preservatives, and metallic impurities must often be looked for. Chemical analyses of ground or pulped vegetable substances serve only to a limited extent in determining their identity or purity. Microscopic examination supplies this deficiency. Each seed, fruit, root, bark, leaf, and flower consists of more or less characteristic tissues and cell contents which can be found under the microscope no matter how finely the material may be pul- verized. Mineral Foods. Although there are a number of mineral substances essential for animal life most of these are present in sufficient amount in animal and vegetable foods. Salt is the one exception. Baking powders are semi-mineral foods. They are not, however, used for any purpose but to generate carbon dioxide gas, which passes off in baking, leaving behind the fixed prod- ucts of the reaction. Calculation of Calories. The function of foods is partly to repair the tissues, for which purpose proteins and mineral salts are of chief importance, and partly to furnish fuel for muscular energy and animal heat. The fuel value is expressed in calories, the unit being the heat required to raise one kilogram of water i°C. The calories of a given food may be determined by actual combustion in a delicate piece of apparatus known as the Bomb Calorimeter, or else by calculation from the analysis. Rubner uses in his calculations for one gram of each of the three classes of nutrients, carbohydrates, proteins, and fats, the factors 4.1, 4.1, and 9.3, respectively. Calculated to a pound (453.6 l! INTRODUCTION 5 grams), the fuel value of the carbohydrates and proteins is i860 calories each and of the fats is 4218 calories. Further details with regard to calories and protein require- ments will be found in the works on human nutrition and cattle feeding mentioned on p. 6). Province and Limitations of Food Analysis. Notwithstand- ing the endless number of chemical compounds contained in foods, the accurate determination of only a limited number is possible with our present knowledge. These limitations of food analysis do not seriously detract from its value in the study of nutrition, in the identification and commercial valuation of foods, and in the detection of adulteration. A few determina- tions such as crude fat, crude fiber, crude protein, ash, nitro- gen-free extract, sugar, alcohol, acids, chemical and physical constants, flavoring principles, and alkaloidal substances are sufficient for most practical purposes, while the estimation of a limited number of minor constituents serves for finer distinc- tions. For example the determination of the fat (total glycerides) of milk enables the student of dietetics or nutrition to form his estimate of the food value due to fats, the dairyman to estimate the amount of butter obtainable from the milk, and the food inspector to decide whether or not the milk has been skimmed. Again the chemical and physical constants of a fat or oil enable the commercial or inspection chemist to establish its identity or purity without a detailed analysis giving the percentages of the different glycerides, were such an analysis possible. Literature of Food Analysis. Food analysis has come into special prominence in the past generation. During this time scientific journals have been established in the leading coun- tries, numerous articles have been published in these and other journals, and standard works have been written which in some cases have gone through several revisions. Foods in General. The following works in the English language deal especially with the composition and analysis of all classes of food: Blyth, " Foods, Their Composition and Analysis"; Leach, "Food Inspection and Analysis"; Leff- 6 INTRODUCTION maim and Beam, " Select Methods of Food Analysis "; Wood- man, " Food Analysis, Typical Methods and Interpretation of Results." Allen's " Commercial Organic Analysis " (Edited by Leffmann and Davis) devotes sections to the analysis of different classes of foods such as, for example. Dairy Products, (Leffmann, Revis and Bolton, Van Slyke); Meat and Meat Products (Richardson); Fats and Oils (Mitchell, Archbutt, Revis and Bolton); Sugars, Starch and its Isomers (Armstrong) ; and Alcoholic Liquors (Baker, Jones, Schhchting, Leffmann). The Association of Official Agricultural Chemists publishes from time to time the methods of analysis adopted by that body. Dairy Products. Farrington and Woll, " Testing Milk and Its Products"; Richmond, "Dairy Chemistry"; Van Slyke, " Modern Methods of Testing Milk and Milk Products." Oils and Fats. Gill, " A Short Handbook of Oil Analysis "; Lewkowitsch, " Chemical Technology and Analysis of Oils, Fats and Waxes." Saccharine Products. Browne, " A Handbook of Sugar Anal- ysis"; Long's translation of Landolt, "Optical Rotation of Organic Substances "; Rolfe, " The Polariscope in the Chem- ical Laboratory "; Weiclmiann, " Sugar Analysis." Works on Food Technology. Food analysis is but a hand- maiden of more comprehensive subjects, such as food technology, nutrition, and food inspection. Of special value to the student interested in the agricultural, manufacturing, commercial, and sociological aspects of foods are the following: Bailey, " The Source, Chemistry, and Use of Food Products "; Tibbies, " Foods, Origin, Manufacture, and Composition." ' Works on Nutrition. Among the works dealing especially with human nutrition are the following: Jordan, " Principles of Human Nutrition"; Lusk, "The Science of Nutrition"; Sherman, "Chemistry of Food and Nutrition"; Snyder, " Human Foods and Their Nutritive Value." The nutrition of farm animals is treated in Armsby's " Principles of Animal Nutrition." Analyses of Foods will be found in Atwater and Bryant's " Chemical Composition of American Food Materials " and INTRODUCTION 7 Jenkins and Win ton's " Compilation of Analyses of American Feeding Stuffs," both published by the Ofhce of Experiment Stations of the U. S. Department of Agriculture. Outline of the Laboratory Work. The pages which follow give general information as to the composition of the principal foods, explicit instructions for determining the most important constituents which can be carried out in 40 laboratory periods of 4 hours each, and brief statements as to other methods which, because of their unimportance or complicated nature, need not be undertaken by the novice. The subjects considered are arranged in 8 chapters, the practical laboratory work in each chapter requiring from 2 to 8 laboratory periods. Chapter II (4 periods) describes the determination of solids and fat in milk by different methods and tests for preservatives, the methods being those commonly followed in valuation and inspection. Methods for water, fat, salt, and curd in butter are also taken up. Cheese analysis is discussed. Chapter III (2 periods) considers briefly the analysis of meat products and describes a method of determining the preservative sulphurous acid. In Chapter IV (8 periods) the determination of water, fat, crude fiber, ash, and nitrogen-free extract in ground vegetable substances, also of starch in flour are treated at some length and the detection of the ingredients of baking powder is considered. The microscopic identification of ground vegetable substances is taken up in Chapter V (8 periods) . Chapter VI (4 periods) describes the polariscopic method of determining sucrose and other sugars in saccharine products and takes up the detection of adulterants in maple products and of colors in confectionery. The practical work in Chapter VII (4 periods) includes the determination of the principal constants of fats and oils, namely specific gravity, refractive index, iodine number, saponification niunber, and volatile fatty acids. It also describes the qualita- tive tests for cotton seed and sesame oils. Chapter VIII (2 periods) traces analytically the transition of 8 INTRODUCTION sugar in fruit juices to alcohol and finally into vinegar and con- siders the general analysis of fruit juices, alcoholic liquors, and vinegar. Chapter IX (5 periods) is devoted to the analysis of flavoring extracts, the practical work including the determination of vanillin, coumarin, normal lead number, and color of pure and imitation vanilla extract, also lemon (essential) oil and citral (the oxygenated flavoring constituent) of lemon extract. Finally, Chapter X (3 periods) takes up the determination of caffeine in coffee, which is also the active principle of tea and, together with theobromine, of cocoa products. It also discusses other constituents of alkaloidal foods and their determination. Suggestions for Division of Class. As has been noted in the preface it may be desirable to divide the subject matter and the class into groups, thus avoiding duplication of expensive apparatus. No little thought has been devoted to this feature of the book. In the author's experience, multiple pieces of apparatus, such as Kjeldahl digestion and distilling stands, water determination apparatus, and centrifugal machines are most convenient when arranged for twelve determinations, that is, for duplicate deter- minations of six students. That number of students can also to best advantage use on the same day apparatus such as the polariscope, refractometer, Westphal balance, etc. Accordingly it has seemed wise to provide for the division of the class into five groups of six students each and for the division of the laboratory work also into five groups of methods, taking care that each group requires the same number of laboratory periods, namely, 8. This plan is readily carried out by assigning to the first group of students, Chapters II and VII, to the second group. Chapters III, VI, and VIII, to the third, Chapter IV, to the fourth. Chap- ter V, and to the fifth. Chapters IX and X, At the end of the eighth laboratory period each group of students is assigned a new group of methods and so on. If more than one student is assigned to a balance there will be less interference if each is from a different group. Use of Balance, Burettes, etc. No attempt has been made to go into the details of construction or the method of using INTRODUCTION 9 the pieces of apparatus found in every analytical laboratory. If the student is not familiar with them it is assumed that the instructor will arrange for extra periods devoted to such details which will naturally extend the time somewhat beyond that allowed for the course. It is also assumed that reagents and standard solutions will be prepared, and the latter also standardized for the class. Those who have taken a course in quantitative analysis will have had this experience. Sections Devoted to Laboratory Work. The subject matter of the book is of two kinds: (i) detailed instructions for labora- tory Work and (2) general information bearing on the nature, composition, and analysis of foods, including brief statements of principles involved in methods other than those carried out by the student. One without the other would be of Uttle value. The chemist who merely learns the mechanical details of analyt- ical methods can hardly hope to rise above the grade of a routine subordinate; on the other hand the human encyclopoedia of chemical knowledge with untrained hands is of even less credit to the profession. Notwithstanding the equal importance of the two kinds of subject matter it has seemed desirable to indicate exactly what sections deal with details of laboratory practice to guide both the instructor and the student in arranging their time to best advantage. For this purpose a five-pointed star (■*■) at the left of the sideheading is used. Matter other than that starred can be made the subject for recitations. CHAPTER II DAIRY PRODUCTS Milk Composition of Milk. Milk, as it is the sole means of sus- tenance of the young animal,, must be a perfect food, that is, it must contain all the food elements essential for life and in the proper proportion. That different animals are furnished by nature with different proportions of the different food elements appears from the following table: Average Composition of the Milk of Different Animals (Konig) Woman's Milk. Cow's Milk. Goat's Milk. Fat Casein Albumin Ash 3-78 1.03 1 .26 0.31 6.21 3-64 3.02 0-53 0.71 4.88 4-78 3.20 I .09 0.76 4.46 Lactose Total solids 12.59 87-41 12.78 87.22 14.29 85-71 Water 100.00 100.00 100.00 The variation in the milk of different breeds of cows is shown in the following table : Average Composition of the Milk of Different Breeds of Cows (Collier) Holstein- Friesian. Ayrshire. Devon. American Holder- ness. Jersey. Guernsey. Fat Casein and albumin. . . Ash 3 46 3-39 0.73 4-84 3-57 3-43 0.69 5-33 4-15 3-76 0.76 5-07 3-55 3-39 0.70 5-01 5-61 3-91 0.74 5-15 5-12 3.61 0.75 5-II Lactose Total solids 12.42 87.58 13.02 86.98 13-74 86.26 12.65 87-35 15-41 84-59 14-59 85-41 Water 100.00 100.00 100.00 100.00 100.00 100.00 11 12 DAIRY PRODUCTS Colostrum. The foregoing tables of composition do not take into account the abnormal milk, known as colostrum, produced for two or three days after the birth of the young animal. Colos- trum is very high in albumin and consequently in total soHds, but is somewhat deficient in lactose (milk sugar) as shown in the following analyses of colostrum from twenty cows : Average Composition of Colostrum (Engling) Fat 3.37 Casein 4 . 83 Albumin iS-8s Ash 1 . 78 Lactose 2 . 48 Total solids .• 28 . 3 1 Water 7169 Milk also varies in composition according to the period of lactation, the percentage of fat increasing toward the end of the period, " Strippings " are also richer in fat than " fore milk " or that drawn first from the udder. Commercial Value of the Constituents of Milk. While in meat the proteins are the most expensive constituents, the fat being less highly prized and often wasted, in the case of milk the reverse is true, the commercial value being largely deter- mined by the amount of fat present. In the form of butter, milk fat is worth two or three times as much as other animal fats, while skim milk, which differs from whole milk only in that the fat is largely removed, is a proverbially cheap food. Because of the high commercial value of the fat the determination of this constituent is the most important of the analytical processes which have been devised and in the buying and selHng of milk is ordinarily the only one undertaken. Milk Standards. In order to prevent the watering and skimming of market milk, as well as to exclude the product unduly poor in composition due to breed, individual character- istics, and other causes, standards have been fLxed by Federal, SAMPLING OF MILK 13 MHIM State and municipal authorities. The Federal standard, which has been adopted by various States and cities, excludes milk drawn fifteen days before and ten days after calving and requires not less than 8.5 per cent of solids not fat and not less than 3.25 per cent of milk fat. Sampling of Milk. Proper sampling is very simple but too often neglected. An analysis of a sample taken from the bottom or the top of milk that has stood long enough for the cream to rise is worse than useless. The milk first drawn from the udder, like skim milk, is poor in fat, while the last of the milking is really cream. Whether the lot of milk be large or small, it should be well mixed before sampling. This is accomplished by thorough stirring with a dipper, by pouring three times from one pail or bottle to another, or, if the quantity is small, by shaking in a bottle. Immediately before the sample is divided or portions are removed for analysis this mixing must be repeated. Composite Samples. It is obviously im- practicable to mix together the contents of several cans and still more so of all the cans of a large shipment. In such cases a composite sample accurately representing the whole lot may be secured by mixing small portions obtained from each can after thorough stirring. If the cans all contain approximately the same amount the portions can be of the same size, otherwise to be strictly accurate they should be propor- tional to the amount. This latter end is secured without calculation by using a sampling tube or " milk thief," which takes out a column equal in height to the height of the milk in the can. The Scovell sampler, shown in Fig. i , has holes in a cap at the bottom end which should be opened by pushing down before using. The tube is then slowly lowered to the bottom of the can, allowing the milk which enters through the holes to rise to the same level as outside. The holes are closed by pushing the Fig. I. — Scovell Milk-sampling Tube. 14 DAIRY PRODUCTS cap against the bottom of the can and the milk is delivered into the sample bottle. A composite sample of the milk furnished from day to day- may be secured in the same manner, adding a small amount of potassium bichromate as a preservative. Such a sample may be tested at the end of a week or even a month, ^Material for Laboratory Practice. For the analytical work, a quart of milk, a half pint of cream (not over 25 per cent fat), and a pint of skim milk should be provided. To the sample of milk add 2 to 3 drops of 40 per cent formaldehyde solution so that i part of the gas will be present in about 20,000 parts of the cream. To the sample of skim milk add i gram of borax. These preservatives will be tested for by well-known methods; they will not in- terfere with the quantitative determinations undertaken. ^Determination of Specific Gravity of Milk by the Lactometer. Thoroughly mix the sample of whole milk as described. Transfer to a glass cylinder, insert a Quevenne lactometer (Fig. 2), and after the temperature becomes constant let each student read the density on the Quevenne scale and the temperature on the Fahrenheit scale. Correct to 60° F., using the table on page 211. The readings on the Quevenne scale are the figures in the hundredth and thousandth place of the specific gravity expressed as whole num- bers. For example the reading 31 corresponds to the specific gravity i .03 1 . Accordingly to convert Quevenne readings into specific gravity prefLx i.o. After determining the specific gravity again mix the whole milk sample and transfer to as many two-ounce bottles as there ■¥■ See page 9 for explanation of the use of this star. J Fig. 2. — Quevenne Lactometer. TOTAL SOLIDS OF MILK 15 are students. Stopper each bottle with a clean cork. As only fat by the Babcock method will be determined in the cream and skim milk samples these need not be divided. The specific gravity of milk of standard quality, which ranges between 1.02 and 1.035, i^ lowered by watering and raised by skimming. While the lactometer may detect one or the other fraud, unfortunately it may show a normal reading if both forms of adulteration have been practiced. It is accordingly necessary to determine, in addition to the specific gravity, the fat and cal- culate the total solids or else the total solids and calculate the fat. A more certain procedure is to determine both the fat and total solids by analysis, using the calculated amounts as a check. Duplicate Determinations. The maxim '' Eine Analyse ist Keine Analyse" should ever be kept in mind. No analyst, however experienced, is infallible. Even the agreement of the results by the same analyst is no proof of their accuracy, as the same error may have been made in both cases. It is therefore desirable in important work that different chemists make the determinations, using different reagents or even dif- ferent methods. The author strongly recommends that all analyses, except such few as are specially noted, be carried out by the student in dupHcate. If two methods are used for the same constitu- ent, as is true of the total solids and fat of milk, one deter- mination by each method will suffice. ^Determination of Total Solids of Milk in an Open Dish. The dish should be of thin metal, with a flat bottom. If made of platinum the ash can be determined after weighing the soHds in the same |i|f||{|^ ^iMiiBlIllk dish by heating at dull redness in a '^f^f'^^ muffie furnace. Owing to the expense ^--:!!1]Jn^^^^ : ; ; ■ j j i i|||||||p^ of platinum it is recommended to ^ ^. , , , ^. , . 1 . . Fig. 3. — Tinned Lead Dish, use tmned lead dishes, 22 m. m diameter and ly^ in. high, such as are made for capping wide- mouth bottles; these cost less than two cents each and can be thrown away after using (Fig. 3). Aluminum or nickel dishes are suitable but cost more. Tin box covers answer the purpose. 16 DAIRY PRODUCTS Weigh accurately the dish — the use of a desiccator at this stage is unnecessary — mix the sample by shaking, and by means of a 5 cc. pipette transfer to the dish 5 grams, which will be slightly less than the contents of the pipette filled to the mark. Although the results are equally as good if any amount from 4 to 6 grams is used, still in practical work a great amount of figuring and possible mathematical error will be avoided by using exactly 5 grams, and with little additional labor. An error of two or three milligrams in weighing the milk will not appreciably affect the result — in fact evaporation, if too long a time is taken up in the weighing, will cause a more serious error. Evaporate on a boiling water bath, using a ring with an open- ing only slightly smaller than the bottom of the dish. At the end of two to three hours wipe the bottom of the dish dry, place in a desiccator while hot, cool fifteen minutes, and weigh. Calculate the per cent of soHds from this weight. The desiccator for food analysis (Fig. 4), should be of good size (inside diameter at least 6 in.), so as to hold several dishes with a diameter of 2^ in. These can be supported on a circular piece of wire gauze, cut to fit the desiccator, or on a perforated porcelain plate. Three dishes can be arranged in a triangle and one placed in the mid- dle on top of these. While the evaporation is going on proceed according to the following method. * Determination of Total Solids of Milk by the Asbestos Method. This method, devised by Babcock, is really prelimi- nary to the extraction of the fat with ether (p. 21). The deter- mination of total solids is accordingly incidental and furnishes for our purpose a check on the open-dish method. When the percentage of fat is obtained by the Babcock centrifugal method, Fig. -Desiccator with Gauze Disk. Wire TOTAL SOLIDS OF MILK 17 the open-dish method furnishes the readiest means of determin- ing the total soHds. Process. Heat for a minute or two in the flame of a Bunsen burner 2 to 2.5 grams of woolly asbestos (free from fine and brittle material), and introduce into a hollow cyHnder of perforated sheet brass 60 mm. high and 20 mm. in diameter, closed 5 mm. from the bottom with a disk of the same material Fig. 5. Fig. 6. Fig. 5. — Perforated Metal Cylinder for Milk Analysis. Fig. 6. — Water Oven. (Fig. 5). The perforations should be 0.7 mm. in diameter and about 0.7 mm. apart. Cool in a desiccator and weigh. Shake the whole milk sample, measure out 5 cc. with a pipette, allow to deliver slowly on to the asbestos in the cylinder and weigh. As there is no means of removing any of the milk after it has been added to the asbestos, it is easier to use 5 cc. than exactly 5 grams. Dry in a boiling water or steam oven (Fig. 6), for about four hours, cool in a desiccator, and weigh. During the first part 18 DAIRY PRODUCTS of the drying, the door of the oven should be opened from time to time to allow escape of the water vapor. Half of the drying can be carried out on the day the portion is weighed out, the remainder on the next day before extracting with ether. While the milk in the open dish and in the perforated cylinder is drying make single determinations of fat in the whole milk, skim milk, and cream by the Babcock test. * Determination of Fat of Whole Milk, Skim Milk, and Cream by the Babcock Centrifugal Method ("Babcock Test"). The apparatus consists of a 17.6 cc. pipette for measuring the milk (Fig. 7), test bottles with different diameter of neck for milk (Fig. 8), skim milk (Fig. 9), and cream (Fig. 10), a cyHnder of 17.5 cc. capacity for measuring the acid (Fig. 11), and a centrifugal machine. The skim-milk bottle has a double neck consisting of a larger tube for introducing the milk, acid, and water, and a smaller tube for measuring the fat. The centrifugal machine may be obtained in different sizes holding from 2 to 40 test bottles, and arranged for hand, steam, or electric power. A 12-bottle hand machine (Fig. 12), answers very well for laboratory use. Process. Mix the samples and pipette 17.6 cc. (whole milk and skim milk), or weigh 18 grams (cream) into the appropriate test bottle. The pipette should be rinsed with a few cc. of the milk to be tested before measuring out the por- tion for analysis. The pipetted portions of the whole milk and skim milk will weigh sufficiently near 18 grams for practical purposes. Cream, Mik~p" ^t*^*''^ however, varies greatly in specific gravity accord- ing to its thickness, furthermore it froths and clings to the sides of the pipette. In order to insure accurate results the test bottle should be weighed before introducing the cream and enough cream added to increase its weight 18 BABCOCK TEST 19 grams. The chemical balance may be used, but weighing closer than 0.05 gram (about one drop) is unnecessary. Fig. 8. Fig 9. Fig. 10. Fig. 8.— Babcock Milk Test Bottle. Fig. 9. — Wagner Skim Milk Test Bottle Fig. 10. — Winton Cream Test Bottle. Fig. II. — Babcock Acid Measure. Fig. ii. Fig. 12. — Babcock Centrifuge. Introduce 17.5 cc. of commercial sulphuric acid (sp.gr. 1.82 to 1.84). 20 DAIRY PRODUCTS 3£2A/'>V^ In the sample containing formaldehyde note that a violet color appears at the juncture of the two liquids, whereas in the other samples only a dirty brown color is evident. The violet color is dependent on the presence of iron salts in the commer- cial acid. The same color is obtained if a portion of the milk containing formaldehyde is heated with an equal volume of of concentrated hydrochloric acid containing in one liter 2 cc. of 10 per cent ferric chloride solution. Immediately after adding the acid mix the milk and acid thoroughly by a vigorous rotatory motion, holding the test bottle by the neck at a slight angle away from the body. Much heat is developed and the lirnips of curd, which at first form, gradually dis- appear on shaking. After shaking each bottle place in a pocket of the centrifugal machine. If all the pockets are not used arrange the bottles symmetrically to avoid excessive vibration. If the machine is cold it should be heated by a quart or more of boiling water. When the machine is full, whirl at the rate of 800 to 1000 revolutions per minute, according to the diameter of the frame, for five minutes. Fill each bottle to the neck with boiling water from a wash bottle and whirl two minutes longer. Add Fig. 13.— Neck of Milk boiling water nearly up to the top gradua- Test Bottle, Showing . , . , • ,- , • , 1 • Top and Bottom of ^^^^' ^hirl agam for two mmutes, and im- Fat Column. merse the bottles nearly to the top of the neck in a tank of water at about 60° C. Remove one at a time for reading the fat column. Read the top of the top meniscus (Fig. 13, 6) and immediately after the bottom of the bottom meniscus (Fig. 13, a). The difference between the two readings is the percentage of fat. Empty the bottles while hot, shaking continually, and clean with hot water. Although both the milk and the fat are measured the results are in percentage by weight. As already stated 17.6 cc. of milk FAT OF MILK 21 weigh approximately i8 grams. The volume corresponding to lo per cent of fat on the neck of the test bottle is 2 cc. As the specific gravity of the liquid fat is 0.9, 2 cc. corresponds to 1.8 grams of fat and, therefore, to 10 per cent of 18 grams of milk- After the milk or cream is pipetted into the test bottle the remainder of the process may be postponed a day or two, as souring does not affect the results. When these tests are fin- ished the total soHds by the open-dish method can be cooled in a desiccator and weighed. ^Determination of Fat by Extraction with Ether. On the next day, while the drying of the milk by the asbestos method is being finished, preparations should be made for the extraction of the fat with ether. Ether extraction, whether of fat in milk or of the crude fat in animal or vegetable products, is carried out in a so-called con- tinuous extractor, i.e., an apparatus in which the ether, after dissolving a portion of the fat of the material and discharging into the extraction flask, is volatilized, condensed, and again allowed to act on the material, the steps in the process being repeated automatically and continuously until the extraction is complete. The Soxhlet Extractor^ shown in Fig. 14, depends on the inter- mittent action of a glass syphon. The ether gradually condenses into the extraction tube containing the material until it rises to the top of the siphon, when it is discharged into the extraction flask. This ingenious apparatus, although well adapted for certain purposes, is not thoroughly satisfactory for the deter- mination of fat or ether extract, as it is fragile, expensive, employs a large quantity of ether, and requires too large an extraction flask for accurate weighing. The Johnson Extractor ^ (Fig. 15) obviates all these defects. The extractor proper E consists of a vertical tube 175 mm, long and 26 mm. in diameter (inside measurement), provided with a bulge at the bottom, to prevent trapping of the condensed ether, and a delivery tube attached at an angle of about 45°, so that the condensed ether strikes the neck of the extraction flask ^ S. W. Johnson, Amer. Jour. Sci., 1877. p. 196. 22 DAIRY PRODUCTS Fig. 14. Fig. IS- ^ ^ , ^^«- 14-— Soxhiet Extractor. Fk. .j.-Johnson Fa. Extractor with Perforated Cylinder for Milt Analysis, FAT EXTRACTORS 23 F, thus avoiding spattering. The extraction flask has a capac- ity of 30 to 35 cc. and is attached to the dehvery tube by a carefully bored cork. The reflux condenser C is merely an ordinary Liebig condenser, set up in a vertical position and attached by a bored cork at its delivery end to the extractor. The same condenser can be used both for distillation and reflux- ing, according to the way it is set up. A support with a suitable Fig. 16. Fig. 16. — Cork Borers. Fig. 17. — Cork Borer Sharpener. Fig. 17. clamp serves to hold the condenser firmly in position; the extractor and extraction flask hang suspended with no support other than the corks by which they are attached. The flask is heated by a Bunsen flame impinging against a piece of sheet metal which rests on a ring attached to the condenser support. Instructions. Although only a single extraction of fat in milk need be made, the duplicate determination having been carried out by the Babcock centrifugal method, two extractors cormected with Liebig condensers should be set up, as both will 24 DAIRY PRODUCTS be needed later in the determination of the crude fat in vege- table products. In boring holes in the corks (which should first be rolled until soft), be sure that the borer (Fig. i6) has a keen edge, secured by means of a " cork borer sharpener " (Fig. 17), and that it bores a smooth hole into which the tube fits without danger of leaking. Do not use a rat-tail file; it will be found that one of the borers in a good set, properly sharp- ened, will cut a hole into which, without further treatment, a given tube will fit accurately When the apparatus is set up, place an identification mark on the extraction flask. This is best done with a lead pencil on an etched or ground spot. The etching fluid, known as " diamond ink," applied with a brush, or a few strokes with the flat surface of a file moistened with water, gives the desired surface. In using any hydrofluoric acid preparation be careful not to get any on the skin, as it makes serious wounds. Weigh the flask without drying in a desiccator, and without a stopper. If special accuracy were important a counter- poise flask of the same size but slightly less weight could be used, thus obviating the slight error due to the variable amount of moisture which condenses on the surface. Attach the flask to the lower end of the extractor and place the dried and weighed perforated cylinder with asbestos and milk solids in the extractor. Pour 8 to 10 cc. of anhydrous alcohol-free ether through the cylinder, attach the extractor to the condenser, run water through the latter, and heat the flask cautiously. Ether free from water and alcohol is required, as these would extract sugars and other substances from the residue. The ether in the form of vapor passes up through the extractor, is liquefied in the condenser, and is returned drop by drop through the asbestos into the extraction flask. The fat gradually ex- tracted from the milk solids remains in the flask, but the vaporiza- tion and condensation of the ether continue without intermis- sion as long as the heat is applied. After two hours — the end of the laboratory period — the extraction is complete. Turn out the lamps, remove the flask, and allow to stand until the next day, when the ether should be BORAX IN MILK 25 driven off over a register or in some other warm place and the flask, with the fat, dried in the boiling water oven for two hours. Cool, weigh, and calculate the percentage of fat. Compare with the percentage obtained by the Babcock test, also compare the percentages of solids obtained by the two methods. The percentages of fat by the extraction method are accurate to the second place of decimals, while those by the Babcock test vary from one- to two-tenths of a per cent. For ordinary purposes the shorter method is suffi- ciently accurate. Practically all the milk and cream sold for butter and cheese making in the United States are now valued by the Babcock test. ^Calculation of the Total Solids from the Specific Gravity and Fat. Given these data a close approximation to the true percentage of total solids may be obtained from the table on page 212 or by the use of the Richmond shde rule (Fig. 18). Compare the results thus secured with those by direct drying. ^Testing Milk for Borax and Boric Acid. Test the whole milk and skim milk by the fol- lowing method: To 10 cc. of the sample in a watch-glass, add 6 drops of concentrated hydrochloric acid and mix thoroughly with a glass rod. Moisten a strip of turmeric paper with the mixture and dry on a clean watch-glass heated over a water bath. If borax or boric acid is present the paper will turn brick red, changing to a greenish color with a drop of ammonia water. Brief Statements of Methods for the Deter- Fig mination of Other Constituents of Milk. The Protein, including casein and albumin, is obtained ToT 18. — Richmond Milk Scale. by determin- 26 DAIRY PRODUCTS ing the total nitrogen by the Kjeldahl method (p. 65), and multiplying by the factor 6.38. Lactose or milk sugar is esti- mated by copper reduction, following the same method as is used in the estimation of dextrose (p. 76), but taking into account the difference in the reducing power of two sugars. Before applying the method it is necessary to remove the proteins and fat by precipitation with copper sulphate. The proteins form copper compounds which entangle the fat mechanically, thus permitting the removal of both classes of interfering substances by one filtration. Butter Composition of Butter. Butter consists of the fat of milk mechanically mixed with water, a small amount of casein or curd, and added salt. Traces of lactic acid resulting from the fermentation of the sugar are also present. The average com- position of 350 samples analyzed by Farrington ^ at the Chicago World's Fair, is as follows: Water 1 1 • 57 Fat 84.70 Curd (casein) .95 Ash (including salt) 2 . 78 ^Preparation of Sample of Butter for Analysis. Place a half pound of butter in a pint fruit jar, fasten the cover securely in place, and keep in a warm place or in hot water until the butter is melted. As lumps of the butter may remain unmelted for some time, care should be taken to heat long enough to melt completely the whole mass. Without opening, cool the jar and contents under a stream of cold water, shaking continually. When the mass of butter has solidified, dry off the outside of the jar and keep in a refrigerator until needed. The sample thus prepared (previous to the exercise) will be homogeneous and sufficient for the duplicate analyses of over fifty students. * Farrington and WoU: Testing Milk and its Products, 23d ed., p. 259. BUTTER 27 ^Determination of Water, Fat, Curd, and Ash of Butter in One Weighed Portion. Weigh two tinned lead dishes, such as were used for the determination of total solids in milk (p. 15), and place in each dish 2 grams of the butter sample. Dry in a boiling water-oven for two and one-half hours, cool in a desic- cator, and calculate the loss in weight as percentage of moisture. While the dishes are in the oven prepare two porcelain Gooch Fig. 19. — Filtering Apparatus for Gooch Crucibles with Chapman Pump. crucibles, diameter 35 mm. (Fig. 19 G'), as follows: Connect the crucible G by means of a piece of large, thick rubber tubing with the filter tube T, the stem of which passes through the rubber cork of the tubulated Erlenmeyer flask F, made of thick glass so as to resist a vacuum. Connect the tubulature with the filter pump P and pour on the crucible a quantity of pulped asbestos, suspended in water, sufficient to form a blanket about i in. thick. 28 DAIRY PRODUCTS The asbestos used should have previously been chopped into small pieces, digested with hydrochloric acid (sp.gr. 1.125) on a water bath for an hour or two, and washed by decantation. When needed it is shaken with water and removed to the crucible while in suspension, using suction. Asbestos prepared for filter- ing copper suboxide in sugar analysis may also be used (p. 76). Wash once with water and, to facilitate drying, with a little alcohol. Dry cautiously over a piece of asbestos paper, finally raising the heat to a scorching temperature. Allow to cool, at first in the air, finally in a desiccator and weigh. To each of the dried residues obtained in the water deter- mination add enough gasoline from a wash bottle to about half fill the dish and stir carefully with a short glass rod. By means of the rod form a lip on the edge of the dish. Pour the gaso- lene and any suspended matter onto one of the Gooch crucibles connected with the suction apparatus. Repeat the treatment several times until the fat appears to have been dissolved, then transfer to the crucible all the insoluble matter, using a " poUceman," or the ball of the little finger, and a stream of gasolene to remove any that may adhere to the dish. When the dish is clean, wash down the sides of the Gooch crucible with gasolene and continue the washing with several more portions, allowing the crucible to empty after each addition. Dry the crucible in a boiling water oven for one to two hours, cool in a desiccator and weigh. The increase in weight is ash (including salt) and curd. Ignite cautiously on a piece of asbestos paper, or in a muffle furnace, at a dull red heat until the residue is white or gray. Cool (finally in a desiccator) and weigh. The loss since the preceding weighing is curd (casein), the difference between the final weight and the weight of the crucible as first prepared is ash, including salt. Calculate both curd and ash in percentages of the butter sample. The characters of butter fat, as compared with other fats, will be considered in Chapter VII. The Gooch Crucible used in the preceding and many other methods of analysis is a great labor saver in the analytical CHEESE 29 laboratory. Before its invention it was customary to perform all nitrations on filter paper, which not only required more time, but necessitated drying of the paper with its contents at ioo° C, or else, when the nature of the precipitate permitted, igniting in a crucible of the ordinary t>^e until the paper was destroyed. In the latter case a correction for the ash of the filter was necessary. The Gooch crucible is really a combination of a filter and a crucible. It may be obtained made of either platinum or porcelain. Cheese Composition of Cheese. Cheese is prepared by the action of rennet (a preparation from calf's stomach) on milk. The casein is coagulated and the fat is mechanically held by the casein, while the whey, containing the sugar, albumin, and cer- tain ash constituents, is drained off. The cheese is finally salted, pressed, and cured. The numerous varieties of cheese owe their characteristics to the kind of milk used (cow's, sheep's, goat's, etc.), the process of manufacture, and the nature of the organ- isms introduced. The following table of analyses taken from Doane and Lawson's compilation,^ shows the composition of common European and American cheese: Composition or Cheese Brie Camembert Cheddar (American) Edam . . . Gorgonzola Limburg (American).. . . . Neufchatel (American) . . . Pineapple (American). . . . Roquefort Swiss (EmmentaD 1 U. S. Dept Analyst. E « am 2 !) ^ \^ . n 2> TYPICAL FOODS 93 found. Finally, with the polarization microscope observe the distinctness of the crosses and their place of intersection. To study the action of iodine on the grains place a drop of the reagent on one side of the mount and draw it under the cover glass by means of a piece of filter paper held on the opposite side so as to suck out a portion of the water. The chief characters are shown in figures 43 to 48, inclusive, or are given in the following table: Wheat Oat Bean Maize Potato Cassava Form Lenticular Polygonal Elliptical or Bean- shaped Polygonal Pear- shaped Truncated Maximum Size 50M lOfl 60/X 35m ICO/U 35m Hilum Central, small Central, small Elongated, large Central, large Eccentric in small end of grain Central, distinct Rings None or in- distinct None or in- distinct Distinct None or in- distinct Distinct Indistinct Aggre- gates None Numerous, up to 100 grains None None None Present, mostly 2 to 3 grains Polariza- tion Crosses Indistinct Distinct Distinct Distinct Distinct Distinct Microscopy of Typical Foods ^Materials for Laboratory Practice. The following unground crude products should be provided: Wheat, rye, corn (maize), oats, buckwheat, peas, cotton seed, linseed (flax seed), black pepper, cayenne pepper, cinnamon (cassia) bark, ginger root, coffee beans, cocoa beans, and tea; also the following ground products for use in practice mixtures: Wheat flour, ground wheat 94 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS bran, ground rye bran, corn (maize) meal, ground oatmeal, buck- wheat flour, ground peas, cotton seed meal, linseed meal, ground black pepper, ground cayenne pepper, ground cinnamon, ground ginger, ground coffee, and cocoa. All of the ground products should be fine enough to pass at least a i mm. (2V in.) sieve. Naturally the three kinds of flour and the cocoa will be impal- pable powders. Six laboratory periods should be given up to studying the general structure of the crude products. After this prac- tice a day may be devoted to the identification of the ground products, both singly and in mixtures, submitted by the in- structor. ■^Wheat. All of the true cereals are dry, one-seeded fruits Fig. 49. — Wheat. Grain in Longitudinal Section and Entire. X8. (Schumann.) consisting largely of the starchy seed, the fruit coat or Pericarp being represented only by the outer bran layers. If a wheat kernel is examined with the naked eye it will be seen that on one side is a deep cleft extending the entire length of the kernel while on the other side at the base is a depression marking the location of the embryo or germ beneath. At the apex is a beard of fine hairs visible under a lens. If a kernel is cut with a penknife into halves, through the cleft (Fig. 49), it will be seen from an examination of the cut surface with the naked eye, that the hard mass within the bran coats consists in large part of the Endosperm which, tested with a drop of iodine in potassium iodide solution, turns deep blue, showing that it is rich in starch. This starch is reserve WHEAT 95 food for the plantlet while beneath the soil. White flour is made from the endosperm. The Embryo {e) does not contain starch, but is rich in oil and proteins, the latter being different from the gluten of the endosperm. It consists of a minute plantlet with a cluster of leaves above, a radicle or embryo root below and, at the side next to the endosperm, a kind of sucker {Scutellum) for drinking in the sugar solution formed by the action of the enzyme diastase on the starch during germination. These details of structure will not, perhaps, be evident in the Fig. 50. — Wheat. Cross section through bran coats and outer endosperm. F pericarp consists of cut cuticle, epi epicarp, hy hypoderm, tr cross cells, and tu tube cells; S spermoderm consists of two brown layers; P perisperm; 5 endosperm consists of al aleurone cells and am starch cells. X160. (MOELLER-TSCHIRCH.) student's section, but he will note the absence of starch as demonstrated by the iodine test. Histology. Fig. 50 shows the outer part of a cross section through the center of a wheat kernel magnified 160 diameters. Such a section is cut with a plano-concave razor or a mechanical section-cutter known as a microtome, after softening the kernel by soaking in water. As it requires considerable practice to secure good cross sections of grains and seeds, the student in the limited time allowed for this course should depend either on permanent mounts or else on the illustrations. 96 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS F is the fruit coat or Pericarp, consisting of three layers, not including the cuticle which is not cellular; S is the seed coat or Spermoderm, corresponding to the skin of an almond or bean; ..--r^^ £ P is the Perisperm or remains of the body of the ovule ; E is the Endosperm, consisting of Aleurone Cells [al) and Starch Cells {am). While cross sections are of great value for a scientific study of a vegetable product, especially in deciding as to the number WHEAT 97 and arrangement of the layers, they are neither so Interesting nor so valuable in identification as surface preparations, that is, the layers removed by scraping the kernel, previously soaked for a time in water, with a penknife. In ground products cross sections are seldom found, the layers being largely in surface sections and, therefore, are seen through the microscope in surface view. Fig. 51 shows the successive layers of the wheat kernel in surface view, although not all of these are readily found or are of value in identification. The student should find all the important layers in water mounts of his own prepara- tion. The outer layer (Epicarp) consists for the most part of Fig. 52. — Wheat. Surface view of cross cells. X300. (K. B. Winton.) elongated, distinctly beaded cells, so arranged as to " break joints" (Fig. 51 epi); at the apex of the kernel, however, the cells are polygonal and from among them arise the hairs of the beard. The Hairs (t) are broad at the base, pointed at the end, and have a distinct cavity the breadth of which is less than the thickness of the walls. They seldom, if ever, exceed looo/x in length. A second and often a third layer of elongated cells, practically the same as those of the epicarp, are also present. The next layer (ir) consists of Cross Cells, so-called because they cross those of the preceding layers at right angles. Fig. 52 shows a group of cross cells more highly magnified. The cross cells are highly characteristic because they are arranged side by side in rows and, therefore, do not break joints. It should also be noted that both the thick side walls and the thin end 98 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS walls of the cells are distinctly beaded, whereas in rye the side walls are indistinctly beaded and the end walls are often swollen. The curious cells of the Intermediate Layer {in) are not likely to be encountered and would not be mentioned were it not that the beginner often runs across the imusual. The Tube Cells (tu) which occur in all the cereals are remarkable in that they do not form a continuous layer, but occur isolated or only here and there in contact with one another. Such a forma- tion is known as Spongy Parenchyma, and the spaces between such cells as Intercellular Spaces. In cross section (Fig. 50 tu), the tube cells appear as rings. All the layers thus far enumerated, together forming a thin skin, make up the fruit coat or Pericarp corresponding to the flesh and stone (excluding the kernel) of the peach or the pod of the pea. None of the cells contains visible contents. The two crossing layers of the seed coat or Spermoderm (Fig. 51, i and 0), are still thinner, the cell walls appearing like mere lines. Were it not for their brown color they would be hardly noticeable. The Perisperm (P), is not evident without special treatment. The Aleurone Cells [at) forming the outer layer of the endo- sperm, although conspicuous because of their thick walls and abundant contents of proteins and fat, are of little value in identification, as they occur in all the cereals and some other grains. By far the greater part of the kernel consists of the thin- walled Starch Cells, also known as flour cells. These contain the Starch Grains {am), which we have already studied (p. 89, Fig. 43), imbedded in two proteins, Gliadin and Glutinin. These latter form with water Gluten, which gives wheat flour its peculiar dough-making properties and contributes so markedly to its nutritive value. The gluten, being a colloid, is not visible in a water mount except on special treatment. The large lenticular starch grains are characteristic not of wheat alone, but of the group wheat, rye, and barley. The RYE 99 experienced microscopist can distinguish the three from one another by the size of these grains. In rye the grains often exceed 50M in diameter, in wheat they practically never reach 50/X, while in barley they seldom exceed 35/1. Characteristic Elements, (i) The hairs (Fig. 51, /; Fig. 54, T), distinguished with difficulty from rye hairs but readily from oat hairs (Fig. 54, A), by their shorter length (less than looo/x) and broad base; (2) the cross cells (Fig. 52), distinguished from rye cross cells (Fig. 53), by their more distinct beads and their thin beaded (not swollen) end walls; (3) the large lenticular starch Fig. 53. — Rye. Surface view of cross cells. X300. (Winton.) grains (Fig. 43), not exceeding 50/x (distinction from rye), but often exceeding 35/^ (distinction from barley). ■*"Rye. The structure is throughout analogous to that of wheat. Study the layers noting the distinctions given in the foregoing paragraph. The difference in the Cross Cells (Figs. 52 and 53) serves to distinguish rye bran and other products containing the bran from the corresponding products of wheat. The difference in the size of the starch grains and the difference in the fragments of cross cells, obtained by special treatment to remove the starch, enable a skilled microscopist to distinguish rye flour from wheat flour. A more certain and often the only ready means of distinction is the following test: Bamihl Test. This test, as modified by the author, consists 100 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS A n r\ Fig. 54. — Hairs from wheat (T) and Oats (J). Xi6o. (Winton.) in mounting 1.5 milligrams of the flour in a drop of water containing in each liter 0.2 gram of water- soluble eosin. Before releasing the cover glass move it back and forth over, the liquid, taking care that none of the flour escapes from be- neath it. By this treatment the gluten of wheat flour and of a mix- ture containing a considerable part of wheat flour forms into rolls which greedily absorb the red dye and are readily seen with the naked eye. Rye flour, since it contains no appreciable amount of gluten, does not yield gluten rolls suflicient to be visible with the naked eye. ■*Oats. Both common barley and oats are known as chaffy cereals to distinguish them from naked cereals, such as common wheat, rye, and maize. It should be noted, however, that there are naked varieties of barley and chaffy species of wheat, although they are not of so common occurrence. The Chaff which closely invests the kernel is strongly silici- fied, as is also true of the stems or stalks of all cereals. The kernel after removal of the chaff is more slender than wheat or rye. Histology. The structure of the chaff of oats and barley is highly interesting and of special impor- tance to the food analyst, but need not be taken up in this short course. CORN 101 Suffice it to say that the two can be readily distinguished under the microscope. None of the layers of the kernel up to the aleurone layer is at all conspicuous. The Hairs of the beard, however, are both striking and characteristic (Fig. 54, ^). They often reach 2000/i in length and are, therefore, twice as long as wheat hairs. They taper not only toward the apex but also toward the base, A^hich is so narrow as to appear almost pointed. The base of wheat hairs is broad. The aleurone layer is striking, but not appreciably different from the corresponding layer of other cereals. The Starch Grains (Fig. 44) of the starch or flour cells resem- ble those of rice, but are unlike those of any other cereal. They are small (seldom over iom), polygonal, and occur in rounded aggregates of from 2 to 100 individuals. As rice does not have hairs, at least on the kernel freed from the chaff, these furnish a ready means of distinguishing oat from rice products. From all other cereal products the starch grains as well as the hairs are valuable means of distinc- tion. Characteristic Elements, (i) The hairs narrowed at the base (Fig. 54, ^); (2) the polygonal starch grains in aggregates (Fig. 44)- *Com (Maize). A longitudi- nal section of the Indian corn or maize kernel (Fig. 55) shows very strikingly the division into oily embryo and starchy endo- sperm. The plantlet of the embryo (at the right), has a distinct Plumule or group of leaves at the top {k) and a Radicle or embryonic root below {w) Fig. 55. — Corn. Longitudinal section, c pericarp; eg horny and ew floury endosperm; sc and 55 scutellum of embyro; k plumule; w primary root. X6. (Sachs.) 102 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS At the center it is connected with the Scutellum {ss and sc), which draws the dissolved starch from the endosperm during sprouting. The Endosperm is partly floury {ew) and partly m K E Fig. 56. — Corn. Cross section of bran coats and outer endosperm. Pericarp consists of ep epicarp; m mesocarp, p spongy parenchyma, and sch tube cells; h spermoderm; is perisperm; endosperm consists of A' aleurone cells and £ starch cells. X160. (Moeller.) Fig. 57. — Corn. Bran coats in surface view, m mesocarp; sch tube cells; p spongy parenchyma; /^ perisperm; A aleurone layer. X160. (Moeller.) horny {eg) the latter condition being due to the protein Zein in which the starch grains are embedded. The bran coats (c), including the aleurone layer, surround the endosperm. Histology. The bran coats are shown in cross section and surface view in Figs. 56 and 57. The cells of the Outer Layers BUCKWHEAT 103 {ep and m) in surface view remind us of the outer layers of wheat, but they are not so distinct, owing partly to the several layers which do not readily separate, and hairs are absent. The appearance of these layers in the yellow, white, or red skin will soon be learned by experience. The Tube Cells (sch), the loose or Spongy Parenchyma (p), and the Aleurone Cells {K) are not of special value in identification. The highly characteristic Starch Grains (Fig. 45) distinguish corn from all other economic products excepting the sorghums, which are not commonly milled. They range from 15 to 35ju in diameter and have a very distinct Fig. 58. — Buckwheat. Cross section. F pericarp with B bundles; derm; £ endosperm; £/» embryo. X16. (Winton.) S spermo- hilum. In the horny endosperm most of the grains are polygonal ; in the floury endosperm most of them are rounded. Characteristic Elements, (i) The outer bran coats con- sisting of several layers of beaded cells; (2) the polygonal starch grains (Fig. 45) up to 35^ in diameter, with distinct hilum. Hairs are absent on the kernel although present in the chaff which, for the most part, remains with the cob in shelling. ■^Buckwheat. Although not a true cereal, buckwheat yields flour and by-products that are put to the same use as those of the cereals. The triangular grain is a dry fruit. Unlike the 104 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS cereals the black hull or Pericarp is readily removed from the seed. The Spermoderm or seed coat is thin and papery of a brown or green-brown color. The Embryo is embedded in the Endosperm and so folded as to appear in cross section under a lens S-shaped (Fig. 58). ♦ Histology. The brown elements of the black hulls need not be studied. The tissues of the seed coat are shown in Fig. 59. Especially noteworthy are the wavy-walled cells of the Outer Fig. 59. — Buckwheat. Bran coats in surface view. Spermoderm consists of outer epidermis, m spongy parenchyma, and ep inner epidermis; al aleurone cells. X300. (MOELLER.) Epidermis (0) which, if indistinct in a water mount, are brought out clearly by drawing a small drop of 5 per cent sodium hydrox- ide under the cover glass. The Spongy Parenchyma (m), with greenish or brownish cell contents, is also worthy of notice. Aleurone Cells like those of the cereals are present. Buckwheat Starch (Fig. 60), is shghtly larger than oat starch, ranging up to over 1 5/i in diameter, but the grains are not so sharply polyg- onal and, although often united to form rod-shaped bodies, do not occur in rounded aggregates. PEAS 105 Fig. 6o. — Buckwheat Starch. X300. (MOELLER.) Characteristic Elements, (i) The wavy- walled cells of the epidermis (Fig. 59, 0) and (2) the spongy parenchyma {m) usually suffice for identification. The absence of rounded aggre- gates distinguishes the starch from oat and rice starch. ■^Peas. Beans and peas are true seeds. They consist of an outer skin or Spermoderm and an Embryo with large Cotyledons containing reserve starch. No endosperm is present in the mature seed, the food for the young plantlet having been eaten, but not digested as it were, during its development. Histology. Fig. 61 shows a cross section of the seed coat or spermoderm and cotyledon. The outer layer of the seed coat con- sists of high (6o-ioom) but narrow cells forming a so-called Palisade Layer (pal). The cavity of these cells is narrow except at the base, where it is somewhat broadened. A curious "Light Line'' (/) follows just within the outer surface of the layer. The next layer is of cells shaped like columns or hour glasses {suh). Both the paUsade cells and Column Cells are isolated by heat- ing a fragment of the skin, mounted in 5 per cent sodium hydroxide solution, and gently pressing the cover glass. After this treatment the palisade cells fall down on their sides while the column cells assume various positions. The relative height of the cells of the two layers aids in distinguishing the different Fig. 61. — Pea. Outer layers in cross section. S spermoderm consists of pal palisade cells with / light line, siih column cells, and p par- enchyma. C cotyledon with am starch cells. X160. (Winton.) 106 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS legumes. In beans each of the cells, corresponding to the column cells of peas, contains a beautiful crystal of calcium oxalate. The Starch Grains {am) of the pea are ellipsoidal, irregularly swollen, or bean shaped, varying in length up to 40^. The hilum is elongated, but not so distinct as in beans or lentils. Many legumes contain starch, some, such as the soy bean and lupine, do not. Characteristic Elements, (i) The palisade cells 60 to loo/x high (Fig. 61, pal); (2) hour-glass or column cells up to I II Fig. 62. — Cotton Seed. / cross section. // longitudinal section. 5 spermoderm; NE perisperm and endosperm; C cotyledons; R radicle. X4. (Winton.) 20/X high {sub)\ (3) irregularly ellipsoidal starch grains up to 40ju {am). ^Cotton Seed. A considerable number of economic seeds are characterized by the presence of oil instead of starch as reserve material. These " oil seeds " yield by pressure or extraction commercial oils, such as cotton seed, linseed, rape, sesame, cocoanut, palm, hemp seed, and poppy seed, which are used for foods, drugs, and various technical purposes, while the residual cake is commonly utilized for feeding cattle. Oil cakes contain a considerable amount of fatty oil which it is impracticable to remove and very high percentages of pro- COTTON SEED 107 tein because of which they are known as " concentrated feeds." lep- FiG. 63.— Cotton Seed. Cross section. S Spermoderm consists of ep epidermis with h liair, br outer brown coat with R raphe, w colorless cells, pal palisade cells, and a, b, c layers of inner brown coat; N perisperm; E endosperm; C cotyledor with aep outer and iep inner epidermis; s resin cavity surrounded by z mucilag cells; al aleurone grains; k crystal cells; g procambium bundle. X160. (WiNTON.) Cotton seed, like the pea, contains its reserve material in its Cotyledons, but the starch is replaced by oil. A seed cut in 108 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS half with a jack-knife shows the thick black hull, seed coat, or spermoderm, and the gray-yellow much-folded cotyledons with minute resin cavities appearing as minute black spots (Fig. 62). Histology. Fig. 63 shows a cross section through the seed coat and cotyledon and Fig. 64, the elements in surface view. Two layers are highly characteristic, viz., the Outer Epidermis (ep) of the seed coat and the Palisade Layer (pal). Fig. 64. — Cotton Seed. Surface view of outer layers, ep epidermis of spermo- derm with h^ hair and sto^ stoma; br outer brown cells; w colorless cells; pal^ and pal^ palisade cells (see Fig. 63); a, b, c layers of inner brown coat of spermoderm; iV perisperm; £ endosperm; af/) outer epidermis of cotyledon with h"^ multicellular hair and sto^ stoma. X 160. (Winton.) The epidermal cells (Figs. 63 and 64, ep), obtained for study by scraping the outer surface of the seed, are of irregular shape with dark contents. Among them are the bases of the Hairs (Fig. 63, A; Fig. 64, // ^) which remain attached to the seed after removing the major part by ginning. These hairs, the cotton fiber of commerce, are strap shaped, more or less twisted, and have a broad cavity or lumen. The palisade cells (Fig. 63, pal) can be secured in suitable form for examination either by cutting thin cross sections of COTTON SEED 109 the hull, using a section razor or a Gillette razor blade, or else by scraping the hull in a plane at right angles to the surface. They are remarkable for their great height (150^1) and their division into an outer part of pure cellulose with a distinct cavity, about 50M from the end, and an inner lignified part with no evi- dent cavity. The other layers of the seed coat are of no especial interest. The Endosperm (E) is reduced to a single layer of cells resem- bling the aleurone cells of the cereals in form and contents. The Perisperm (N), or remains of the body of the ovule, also consists of but one cell layer. The cell walls are curiously fringed. Since both endosperm and perisperm together form only a thin colorless coat neither tissue is prominent. The bulk of the seed consists of the starch-free oily Embryo. In addition to Oil, which has no structure, Aleurone Grains (al) and occasional rosette crystals of Calcium Oxalate (k) are pres- ent. The aleurone grains are only 2 to Sf^ in diameter and can be clearly seen only after removal of the fat from a section with a solvent such as ether and mounting in glycerine or else mounting directly in olive oil. As this involves considerable labor and with rather unsatisfactory results, the student may well reserve his study of aleurone grains until he examines flax seed in which they are large and quite distinct. The Resin Cavities (Fig. 63, s), contain a secretion which dissolves in strong sulphuric acid, the solution being blood-red. In preparing and examining a mount in sulphuric acid take every possible precaution not to get any of the acid on the objectives or other parts of the microscope. Use only the low power objective and be sure it does not come in contact with the cover glass. Characteristic Elements. The microscopic elements which serve for identification of cotton seed meal are (i) the epi- dermal cells of the hull, with yellow walls and dark contents (Fig. 64, ep); (2) the palisade cells (Fig. 63, pal); and (3) the resin cavities (s), the contents of which dissolve in sulphuric acid to a blood-red liquid. 110 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS *Fiax Seed or Linseed. In this oil seed part of the reserve material is in the Endosperm (Fig. 65, £), and part in the Em- bryo (C). Figs. 66 and 67 show the seed coat and endosperm in cross section and surface view. The Epidermis (Fig. 67, ep ^) of the seed coat consists of Fig. 65. Fig. 66 Fig. 65. — Linseed in Cross section. 5 spermoderm or seed coat; E endosperm; C cotyledons. (Moeller.) Fig. 66. — Linseed. Cross section of 5 spermoderm and E endosperm, ep outer epidermis; p round cells; / fiber layer; Ir cross cells; g pigment cells. (Moeller.) transparent, glassy cells. More readily found are the longi- tudinally arranged Fibers (/) with thick walls and ragged cavity, the thin- walled Cross Cells (tr), and the Round Cells (r). Often these three layers may be seen in the same fragment of the hull, by careful focusing. Equally striking are the more or less square Tannin Cells (pig). These have indistinctly beaded walls and brown contents. It should be noted that none of FLAX SEED 111 the cells is perfectly square, but rather five or six sided with one or two of the walls much reduced in length. A perfectly- square vegetable cell is physiologically as impossible as a square honey-comb cell. A razor section of the seed mounted in olive oil, or some other f^QuJi)^ Fig. 67. — Linseed. Elements in surface view, cp^ epidermis of spermoderm; r round cells; / fiber layer; x middle lamellae of fiber layer; Ir cross cells; pig pigment cells; E endosperm with al aleurone grains; ep^ epidermis of cotyledon with slo immature stoma; nics mesophyl. X300. (K. B. Winton.) fatty oil, or else in turpentine or glycerine (one of which will serve for the class) shows the large Aleurone Grains, of the endosperm and embryo (Fig. 66, E). They range up to 20^ in length. Aleurone grains are not, like starch grains, homogeneous in chemical composition. Each grain consists of a ground sub- stance in which are usually embedded one or more Crystalloids 112 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS or protein crystals, one or more Globoids (compounds of lime and magnesia with phosphoric acid and an organic acid), and often crystals or crystal rosettes of Calcium Oxalate. In the aleurone grains of linseed only one globoid and one indistinct crystalloid are present. Characteristic Elements, (i) Fragments consisting of fibers (Fig. 67,/), cross cells (tr), and round cells (r); (2) nearly square tannin cells with brown or yellow contents (pig). "^Black Pepper. The chief characters of four of the prin- cipal spices — black pepper, cayenne pepper, cinnamon, and gin- ger — can be observed in a single exercise; the detailed struc- ture, which could scarcely be mastered in a week, would for our purpose be of little more value. Black pepper is the dried immature berry of a vine growing in the Orient. White pepper is the mature berry from which the hull has been re- moved. The reserve material is in the form of starch and is contained, not in the endosperm as in wheat or in the embryo Fig. 68.— Black Pepper, ^s in the pea, but in the Perisperm (Fig. ongi u ina sec ion ^g^ ^^^ ^-^^ robustly developed body of sperm; N perisperm; the ovule which in most plants largely dis- FS pericarp and appears on ripening. spermoderm. X 3- Histology. Fig. 69 shows the elements (MOELLER.) ^ 1,1, T 1 , 1 of ground black pepper. Just below the Epicarp or epidermis of the berry is a layer {ast) consisting largely of Stone Cells, a kind of cell with thick lignified walls and branching cavities, widely distributed through the vege- table kingdom. The small but hard granules encountered in eating a pear or quince are groups of stone cells and the tough character of raspberry and strawberry " seeds " is due to a protective stone cell layer. Stone cells make up the bulk of nut shells (cocoanut, walnut, etc.), fruit stones exclusive of the kernel (peach, olive, etc.), the woody part of maize cobs, and various hardened tissues, but not of true wood. Stone cells of different products vary in form and size and in the thickness BLACK PEPPER 113 and color of the walls and the nature of the cell contents. Because of these differences the trained microscopist can detect in ground pepper the presence of adulterants such as ground cocoanut shells and ground olive stones, which were formerly added in large quantities. A second layer of stone cells (ist) occurs in the inner portion a/u ist--- ¥ 9 <^ Fig. 69. — Black Pepper. Elements of powder, ep epicarp; ast hypodermal stone cells; bf bast fibers; hp bast sclerenchyma; sp vessels; p oil cells; ist endo- carp; is and as layers of spermoderm; am starch masses. X160. A starch grains, X 600. (Moeller.) of the hull. This portion is not removed in decortication, hence the stone cells occur in white as well as black pepper. As only the inner and side walls are thickened they are known as Beaker Cells. This character is not evident in surface view of the stone- cell groups, but only when individual cells become detached as shown at the right of the group shown in the figure. 114 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS The bulk of the pepper corn consists of a mass of Starch Cells. The ground product contains groups of cells with contents intact {am) , also the starch separated from the cells as individual grains or groups of grains (A). The individual grains are among the smallest found in economic products, being usually 2 to 4 M in diameter and never ejiceeding 6/i. Needle-shaped crystals of Piperine are often evident in ground pepper. Fig. 70. Fig. 71. Fig. 70. — Cayenne Pepper. Epicarp in surface view. X160. (K. B. Winton.) Fig. 71. — Cayenne Pepper. Epidermis of seed in surface view. X160. (K. B. Winton.) Characteristic Elements, (i) The stone cells (Fig. 69, ast) of the outer layer; (2) the beaker-shaped stone cells {ist); (3) the starch cells {am)\ (4) the Hberated starch (A) with minute grains. ■^^Cayenne Pepper. The highly pungent chillies, or fruits of a small podded species of Capsicum grown in Africa, are known in commerce as cayenne pepper or cayenne. The mild fruits of a large podded variety of the garden pepper grown in Hungary yield paprika. Histology. Both kinds of red pepper are non-starchy and CINNAMON 115 contain in the pod tissues drops of Oil which take on an orange- red coloring matter also formed in the cells. Mounted in concentrated sulphuric acid the oil drops become indigo blue. The tissue characteristic of cayenne alone is the Epicarp, or outer epidermis of the pod, consisting of more or less rectangular cells with wavy walls (Fig. 70). The Epidermis of the seed consists of remarkable cells with curious, wrinkled walls resembling the convolutions of the intestines (Fig. 71). As seen in surface view these cells are much alike in cayenne and paprika, but no such cells occur in any other common food product. The seed tissues containing oil and aleurone grains are not remarkable. Characteristic Elements, (i) The more or less rectangular cells of the epicarp with wavy walls (Fig. 70) ; (2) the orange- red oil drops becoming indigo blue with sulphuric acid; (3) the intestine cells of the seed (Fig. 71). ^Cinnamon. The moderately thick bark which in import trade is designated cassia when ground is known to the house- wife as cinnamon. True or Ceylon cinnamon is a very thin bark used chiefly in medicine. Histology. The scientific study of barks involves a knowl- edge of the so-called Fibro-vascular Bundles, forming the con- ductive system of plants. Such a study, although highly interesting, would carry us beyond the limits of our work. For diagnostic purposes we need consider only such elements as are most conspicuous in the powdered material, namely the bast fibers, the stone cells, the cork cells, and the starch grains. The Bast Fibers (Fig. 72, bf) resemble stone cells in general structure and chemical composition, but are elongated, pointed at both ends, and have a smooth (not branching) cavity. The flax fibers used in making linen fabrics are bast fibers. The St07ie Cells are either thickened on all sides (st) or only on one side (stp). Cork Cells (P) are present if the bark has not been deprived of its outer layers by scraping. The cork of commerce is the highly developed cork layer of an oak grown in 116 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS Spain. Owing to the infiltrated Suberin, cork cells repel water and form a protective coat for the tree or plant. All the pre- ceding elements are best seen after treating a water mount with sodium hydroxide; the starch, however, must be examined in the water mount. The Starch Grains (B) range usually from lo to 20^1 in diam- eter, and occur mostly in aggregates of 2 to 4 individuals. They Fig. 72. — Cinnamon. A elements of powder: bf bast fibers; st and stp stone cells; pr and bp parenchyma; P cork. X160. B starch grains, X600 (MOELLER.) have rounded or flat sides according to their location in the aggregates. A distinct hilum is evident. Characteristic Elements, (i) Bast fibers (Fig. 72, bf); (2) stone cells (st, stp); (3) starch grains (B), 10 to 20/i, with distinct hilum, occurring mostly in aggregates of 2 to 4. ■^Ginger. The dried underground stem or root of the ginger plant comes into the market simply washed or else scraped. A coating of chalk is added to some varieties the prod- uct thus limed, being, it is claimed, less susceptible to the attacks of insects. Histology. The rootstock consists in large part of paren- GINGER 117 chyma cells filled with Starch Grains which are characteristic because of the rounded angle at one end (Fig. 73, am). Most of Fig. 73. — Ginger. Elements of powder, p parenchyma with starch grains and ol oil masses; am starch grains; / bast fibers; sea vessels; pig pigment; su cork. X160. (K. B. Winton.) 7>/s. Mk Em II Fig. 74. — Coffee. I cross section of berry, natural size. Pk outer pericarp; Mk endocarp; Ek spermoderm; Sa hard endosperm; Sp soft endosperm. // longitudinal section of berry, natural size; Dis bordered disc; Sc remains of sepals; Em embryo. Ill embryo, enlarged: cot cotyledon; rad radicle. (TscHiRCH and Oesterle.) the grains are egg shaped and 2'o to 30/1 long, although smaller and larger grains (up to 50/x) occur sparingly. The fibrous 118 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS material of the rootstock contains Vessels (sea) with reticulated thickenings and Bast Fibers (/) with rather thin walls and broad cavities. Characteristic Elements. (i) Starch grains with rounded angle at one end (am); (2) reticulated vessels (sea); (3) bast fibers (/) with thin walls and broad cavity. ^Coffee. In a laboratory period the student can not only Fig. 75. — Co£fee. Spermoderm in surface view, st stone cells; p parenchyma X160. (MOELLER.) learn the general structure of coffee and cocoa, but also the use of the section razor in studying these products. Fig. 74, I and II, shows cross and longitudinal sections of a coffee berry or " bean " natural size. The shelled bean consists of the hard endosperm in which is embedded a minute embryo (III). Histology. The papery fragments of the spermoderm or seed coat, which will be found in the cleft of a coffee bean, COFFEE 119 should first be examined. Scattered here and there over the skin are remarkable Stone Cells of various shapes with porous walls and broad cavities (Fig. JS, st). Often two or more of the cells are in groups. The structure of the endosperm is best seen in a cross sec- tion. Such sections can be secured by holding a coffee bean, which has been softened by soaking or boiling in water, between the thumb and first finger of the left hand and cutting the thin- nest possible shavings with a section razor or Gillette blade held with the right hand. Considerable experience is required for cutting satisfactory sections of certain seeds, but a little practice should enable the student to prepare sections of the coffee bean thin enough to show the general character of the cells. It will be noted that the cell walls (Fig. 76) are not only thick, but have a beaded ap- pearance due to the pits or pores which pierce them, thus furnishing communication from one cell to another. The thickened cell walls con- stitute the chief reserve material which, instead of being in the form of starch or oil, is in the form of cellulose or re- lated carbohydrates. Sec- tions can be cut of small fragments if held between flat pieces of cork. In this manner ground coffee can be distinguished from common adulterants and substitutes, such as peas and wheat. As a preliminary test, a teaspoonful of the sample should be stirred in a glass of cold water. Peas, cereals, and chicory will sink at once, while coffee floats. Chicory quickly imparts to the water a dark color. Characteristic Elements, (i) Stone cells of the papery seed Fig. 76. — Coffee. Cross section of outer layers of endosperm showing knotty thickenings of cell walls. X160. (MOELLER.) 120 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS coat (Fig. 75, st); (2) reserve cellulose in the form of knotty thickened or beaded walls of the endosperm (Fig. 76). •*Cocoa Bean. The seed of the cocoa or cacao tree, known as the cocoa bean (Fig. 77), consists of a leathery hull or shell and an embryo with folded but fleshy cotyledons containing the reserve material, which is partly starchy and partly oily, the latter predominating. Cocoa beans yield after roasting, shelling, and grinding, the chocolate of commerce. The heat Fig. 77. — Cocoa. 7 entire fniit, Xi; // fruit in cross section. Ill seed (cocoa bean), natural size; IV seed deprived of spermoderm ; V seed in longitudinal section, showing radicle (germ); VI seed in cross section. (Winton.) of the grinding melts the fat or cocoa butter, and as a con- sequence, the product which runs from the mill is a thick paste, which hardens on cooling to a waxy mass known as plain or bitter chocolate or chocolate liquor. Cocoa is the cake remaining after pressing out about half of the fat, reduced to a powder. Histology. Fragments scraped from the shell of a cocoa bean should first be examined. In these will be seen numerous spirals, like spiral springs, which are the thickenings of Spiral Vessels. These give rigidity to the vessels, serving the same COCOA 121 purpose as the spiral iron wires in the flexible pipes for gas drop lamps. Spiral vessels occur also, but sparingly, in black pepper (Fig. 69, sp). Cross sections should then be cut of the cotyledons without soaking, the high percentage of fat being sufhcient to make them soft, yet firm. These sections may be examined directly in water, but the fat will greatly interfere with the observation. It is better to remove the fat from the section, previous to Fig. 78. — Cocoa. Cross section of outer portion of cotyledon, sho\ving hairs and starch parenchyma. (Moeller.) mounting in water, by treating with several successive portions of ether or chloroform in a watch-glass, or else to mount in turpentine. In either case the starch grains will be evident, but the water mount of the extracted sections has the advantage that the iodine test can be applied. Cocoa Starch (Fig. 78) resembles that of cinnamon. The grains are 4-1 2/x in diameter, and occur in aggregates of two to four individuals. Because of their grouping into aggregates, they often have both rounded and angular outlines. 122 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS Characteristic Elements, (i) Numerous spiral vessels in the shells; (2) starch grains 4-1 2/i in diameter with evident hilum, occurring in small aggregates. *Tea. Both black and green tea consist of the dried leaves of Thea Chinensis, the difference in color being due to the process of drying. The leaves (Fig. 79), as may be seen by spreading out the moist residue after preparing the beverage, are rather thick, glossy on the upper sur- face, short-toothed, and veined in such a manner that the main veins branching off from the midrib form near the margin loops, connecting them with adjoining veins. Histology. The structure of leaves bears an obvious relation to their function, namely, Photosynthesis, the formation of carbohydrate matter from carbon dioxide of the air and water of the soil in the sunlight through the agency of chlorophyl grains. Fig. 80 is a cross section of a tea leaf through a Stoma. Beneath the stoma there is an air space surrounded by loosely arranged cells containing Clilorophyl Grains, and often crystals of Calcium Oxalate. It is here that photosynthesis takes place. A large curiously formed Stone Cell extends from one epidermis to the other. Other forms of stone cells are seen at the right {st). A surface section of the lower epidermis (Fig. 81) shows several stomata {sp), also a Hair (//) bent near its base like a cane handle. Characteristic Elements. All of the elements named may be found in the debris obtained by scraping a moist tea leaf. The curious stone cells and the hairs are characteristic. ■^^Examination of Mixtures in Powder Form. Various mix- tures should be made of the following: wheat flour, buckwheat Fig. 79. — Tea. Leaf, nat- ural size. (MOELLER.) MIXTURES 123 flour, maize flour, ground wheat bran, ground rye bran, ground oat meal, ground peas, cotton seed meal, linseed meal, ground oep Fig. 8o. — Tea. Cross section of leaf, icp lower epidermis with / hair and sio stoma; mes mesophyl with chlorophyl grains, large stone cell, and cr calcium oxalate rosette; hit intercellular space; oep upper epidermis; st isolated stone cells. Xi6o. (Winton.) Fig. 8r. — Tea. Leaf seen from below, showing epidermis, with h hair and sp stoma, and m mesophyl. Xi6o. (Moeller.) black pepper, ground cayenne pepper, ground ginger, ground cinnamon, and cocoa. Mixtures of more than two of the materials seem inadvisable, at least if only a day can be de- 124 MICROSCOPIC EXAMINATION OF VEGETABLE FOODS voted to the work of identification. In order that the color may not furnish a clue to the ingredients, pigments such as yellow ochre, burnt sienna, and lampblack may be added to some of the mixtures. Only such mixtures should be pre- pared as correspond to products now or formerly on the market. Ground coffee, pure and mixed with roasted ground peas or roasted wheat, may also be used for practice material. An examination should first be made of a water mount, before and after staining with iodine, to determine whether or not starch is present and, if so, the kind. A drop of sodium hydroxide can then be drawn under the cover glass and the tissues examined. Reference should be made to the para- graphs of the preceding descriptions, giving the " Character- istic Elements " of the products, in interpreting the results of the observations. The following hints may be useful: If lenticular starch grains 30 to 50/i and hairs with broad bases are found, wheat or rye is present. If further search discloses a considerable number of starch grains over 50/x, these are doubtless from rye. In any event cross cells should be looked for, and the char- acters distinguishing wheat from rye noted. As the small starch grains of wheat and rye resemble buckwheat starch, search should be made for the tissues of the buckwheat seed coat, especially the wavy-walled cells and green-brown spongy parenchyma. Oat starch might also be confused with the small grains of wheat and rye or buckwheat starch, were it not for the presence of aggregates of numerous individuals; furthermore the long oat hairs with narrow, almost pointed, bases are characteristic. Bean-shaped starch grains with elongated hilum indicate peas (knowing other leguminous seeds to be absent) and large (up to 35^) polygonal grains are evidence of maize. Pea hulls in the ground product will be indicated by the presence of isolated palisade cells and hour-glass cells. Cotton seed and linseed meals contain no starch, but the tissues of the seed coat leave no doubt as to their identity. Of the spice starches, that of pepper is minute, of cinnamon MIXTURES 125 larger and in small aggregates, and of ginger large with a rounded angle at one end. Cayenne contains no starch but the orange oil drops, the epicarp, and intestine cells are char- acteristic. The stone cells of pepper and the bast fibers as well as the stone cells of cinnamon should be noted. Broad bast fibers and curious vessels are present in ginger. An added cereal or oil seed product may be looked for in spices, also wheat or maize flour in cocoa. Roasted peas, or wheat if present in ground coffee, sink in cold water. The presence and characters of the starch and the elements of the hulls or bran furnish more specific information. Chicory also sinks in cold water-imparting a brown color. CHAPTER VI SACCHARINE PRODUCTS Sugar Characters of Sucrose. Since, at the present time, the world's product of commercial sugar is obtained in about equal quan- tities from the sugar cane and the sugar beet, and further- more, the same sugar is also produced by the sugar maple tree, the frequent use of the term cane sugar as a synonym for sucrose is confusing. Sucrose is a disaccharide with the empirical formula C12H22O11. It is dextrorotatory, that is, a water solution turns a ray of polarized light to the right. Treatment with 2.5 to 4 per cent hydrochloric acid at 69° C. for five to fifteen minutes or at 20° C. for one or two days inverts sucrose, causing it to spUt up into one molecule each of Dextrose ((^-glucose) and Levulose ((/-fructose) as shown by the following equation: Cl2H220ll+H20=C6Hi206+C6Hi206. Although the two cleavage products have the same em- pirical formula, dextrose is an aldehyde (aldose) and dextro- rotatory, while levulose is a ketone (ketose) and levorotatory. The fact that both dextrose and levulose reduce Fehling's copper solution, while sucrose does not, is explained by the hypothesis that the two radicles in the latter are so combined as to destroy the aldehyde group of the one and the ketone group of the other. This difference in configuration is brought out strikingly by the following structural formulae of the three sugars: L27 128 SACCHARINE PRODUCTS CH2OH I HOCH HOCH HCOH HOCH CHO Dextrose (d-glucose) CH2OH HOCH HOCH HCOH C=0 CH2OH Levulose (d-fructose) Sucrose The copper-reducing power of dextrose is slightly greater than that of levulose; on the other hand, the levorotatory power of levulose at ordinary temperatures is considerably more than the dextrorotatory power of dextrose, consequently Invert Sugar, the mixture of equal molecules of dextrose and levulose, is levorotatory. The characters which have been briefly stated are the basis of the most important analytical methods used in sugar analysis. Sucrose is calculated from the figures obtained by polariza- tion, both before and after inversion, while dextrose, levulose, and invert sugar are commonly determined by copper reduc- tion. The Polariscope. The instrument used in sugar analysis known as the Saccharimeter is graduated in terms of per- centages of sucrose, using definite amounts of the material and diluting the solutions to definite volumes. A full consid- eration of the construction of the different types of saccharimeter and the optical principles involved would more than fill the pages of this volume. As is also true of the microscope, there is no more necessity of the student understanding fully the detailed construction or optics of the instrument, than for an artist to understand the anatomy, physiology, and optics of his own eyes. The following brief statements may add interest to the work. SACCHARIMETER 129 Fig. 82, taken from Browne's Ha?idhook of Sugar Analysis, is a diagram of the simplest form of polariscope. The light from the lamp L is polarized by the Nicol prism P, known as the polarizer, that is, the light vibrations which are normally in different planes are reduced to one plane. Another Nicol prism, A, known as the analyzer, is so arranged that it can be rotated about the longitudinal axis of the instrument. With sf I ^ Fig. 82. — Diagram of a Simple Polariscope. the sugar tube T empty, the light polarized by P, as seen by the eye at E, is not altered by A when the axes of the two prisms are parallel; when, however, the axes are crossed, the light is extinguished. If with crossed prisms, a sugar solu- tion is placed in T, the ends being closed by circular glasses, the Ught is no longer extinguished, but passes through with greater or less intensity, dependent on the nature and amount of the sugar. On turning the analyzer so that the field is again black, the amount of rotation due to the sugar solution can be read on the circular scale S. The chief difficulty with an instrument of this simple con- struction would be to determine the point where the field is darkest. To obviate this defect a half-shadow device with a double-field is employed, whereby the left half of the field is dark and the right half is light when the analyzer is crossed with the left half of the field (Fig. 83, /), while the reverse is true when the analyzer is crossed with the right half of the field (Fig. 83, II). The zero point, when the tube is empty. I n III Fig. 83.— Double Field of Half-shadow Saccharimeter. 130 SACCHARINE PRODUCTS and the end point, when an analysis is being made, is shown by the exact correspondence of the two halves of the field (Fig. 83, III). A further improvement is the double-wedge system, in which both analyzer and polarizer are fixed, and the end point is obtained by sliding one quartz wedge alongside of an- other until the thickness of the two is such that the quartz Fig. 84. — Double- wedge Soleil-Ventzke Saccharimeter with Bock Stand and Electric Lamp. rotates the light to the same degree as the sugar solution. The reading is taken on the scale or scales with which the wedge device is provided. Fig. 84 shows a modern instrument with double-field and double-wedge device. * Polarization of Granulated Sugar before and after In- version. The best granulated sugar is practically pure sucrose. It contains only traces of water, ash, and reducing sugars. Weigh out in a nickel sugar dish (Fig. 85) the normal quan- SUGAR 131 tity of sugar for the type of saccharimeter used (26 grams for the Soleil-Ventzke saccharimeter), transfer through a funnel to a loo-cc. graduated flask, rinsing out any that may adhere to the funnel with water. Add enough water to dissolve the sugar and make up to the mark and shake. Direct Polarization. Remove the cap and cover-glass from one end of a 200-mm. observation tube (Fig. 86) , fill with the sugar solu- tion, slide the cover glass into place, and attach the cap. If the tube has one end enlarged as shown in Fig. 86, it is not necessary to avoid an air bubble in the tube, as this will rise, when the tube is in a horizontal position, into the ex- panded part of the tube and thus be out of the line of vision; if, however, both ends are the same size (Fig. 87) the tube Fig. 85.- -Nickel Sugar-weighing Dish and Counterpoise. Fig. 86. — Saccharimeter Tube with Enlarged End. Fig. 87. — Saccharimeter Tube, Simple Form. must be completely filled and the cover glass slid into place in such a manner as to exclude any air bubble. Place the tube in the polariscope, light the lamp, adjust one scale at o, and move the other until the end point is reached. The reading should vary only sHghtly from -f 100. Polarization after Inversion. Pipette 50 cc. of the sugar solution and 25 cc. of water into a loo-cc. graduated flask, add 5 cc. of concentrated hydrochloric acid, mix, place a ther- 132 SACCHARINE PRODUCTS mometer in the solution, and heat in a water bath at 72° to 73° C, so that the solution reaches 69° in 2^ to 5 minutes. Maintain at 69° C. for five minutes, remove the flask, cool rapidly to 20° C. under a stream of cold water, and dilute to 100 cc. Polarize in a 200-mm. tube as before inversion, but multiply the reading, which will be to the left (expressed by the minus sign), by 2 to compensate for the dilution from 50 cc. to 100 cc. Immediately after taking the reading, plunge a ther- mometer in the solution to determine the exact temperature. If the polarization is determined at exactly 20° C, the reading multiplied by 2 should vary only slightly from —32.7. We are now in a position to understand the Herzfeld-Clerget formula, as follows: ' plummet is hung in the air. Distilled water at 15.5^ C, by the thermometer in the plummet, should show a specific gra\'ity of exactly i.ooo. The specific gravity of the liquid sliov/n in the cut is 1.1267, two of the largest size riders being used, one at the end and the other at i on the beam. The specific gravity of the oils (except cocoanut) should be taken within a few degrees of 15.5^ C. and the readings calcu- lated to that temperature by the formula: G =G"H-o.ooo64fr — 15.5), in which G is the specific gravity at 15.5^, G' the specific gravity at T°. Although the factor varies somewhat for the different oils the average (0.00064^ is sufliciently accurate if the tem- perature does not varv- greatly from 15.5°- The fats, also cocoanut oil which at ordinar}- temperatures is a soft fat, should first be melted in a tall beaker over a piece of asbestos, using a low flame. Keeping the temperature as near constant as possible and only slightly above the melting- point, determine the specific gravity and note at the same time the exact temperature. Care must be taken that the melted fat is kept thoroughly mixed and consequently of uniform tem- perature throughout during the observation. As the melting temperature of hard fats must var>' considerably from 15.5^, the factor peculiar to each fat must be used instead of 0.00064 in calculating to the standard temperature as follows: Factors for Correcting Specific Gravity (.\llex) Butter fat o . 00061 7 Tallow 000675 Lard 000650 Cocoa butter 000717 146 FATS AND OILS The specific gravity may also be determined in a pycnometer or by accurate spindles, but for practical work the Westphal balance is to be preferred. The temperature of boiling water, using a special heating apparatus, is often employed and the observed reading compared with the limits obtained on samples of known purity at that temperature. Fig. 89. — Zeiss Butyro-refractometer. ^Determination of the Refractive Index. Two forms of refractometer both made by Carl Zeiss, Jena, are suitable for the examination of fats and oils. One of these, the butyro- refractometer (Fig. 89), has an arbitrary scale on which the degree of refraction is observed directly through the eyepiece, the other, the Abbe refractometer (Fig. 90), gives readings in REFRACTIVE INDEX 147 terms of refractive index on the sector 5 after rotating the tele- scope F until the border line of total reflection passes through the point of intersection of two crossed Hnes. Both employ two Abbe prisms, A and B, on the lower one of which, when open (Fig. 89), a drop of the fat or oil is placed forming, when closed (Fig. 90), a thin film through which the light passes after being Fig. 90. — Abbe Refractometer. reflected upward from the mirror. Both also are arranged to permit the passage of a stream of water of constant temperature through the two prisms, the temperature being indicated by a delicate thermometer. The Abbe instrument, notwithstanding its more complicated construction and more cumbersome scale, is to be preferred for 148 FATS AND OILS general work, as it has a wider range, thus permitting its use for the examination of essential oils and the determination of the total solids of molasses, honey, and syrups from the refractive index. The scale reading obtained with one form of refractometer may be converted into the equivalent of the scale of the other form by calculation or reference to the table on p. 222. Fig. 91. — Zeiss Immersion Refractometer. A third form, known as the immersion refractometer (Fig. 91), used in the examination of milk serum, in the detection of methyl alcohol in liquors, etc., has a prism P, at the end of the tube which, for ordinary use, is plunged in a beaker containing the liquid under examination kept at a constant temperature in a glass-bottomed tank. At the left in Fig. 91, is shown a sec- ABBE REFRACTOMETER 149 tion of the tube with a special metal beaker at the bottom for the examination of liquids excluded from the air. ^Manipulation of the Abbe Instrument. Place the instru- ment in front of a window but not in the direct sunHght. Pro- vide a large tank elevated about 2 ft. above the desk with a suitable arrangement for heating the water and a cock or siphon connected with a rubber tube for conducting a slow stream of the warm water to the refractometer. The tank should be large enough to hold water sufficient for the group of students using it on the same day. Heat the water to 40° C. for the examina- tion of the more solid fats. Afterward water can be added and the temperature lowered to 25° C. for taking the readings on butter fat and the oils. The stream of water enters the lower prism (Fig. 90) at C, passes into the upper prism through the rubber tube and out of the latter at E. When the temperature, as shown by the thermometer in the upper prism, becomes con- stant release the lower prism by opening the screwhead v and allow it to swing into the position shown in Fig. 89. Smear a drop of the oil or melted fat on the glass surface, close, and again fasten in position with v. Rotate the tube with attached sector on the alidade until the border line appears in the field, then by means of the screwhead M, so adjust the compensator that the band of colors, due to dispersion, disappears and a sharp line of demarkation is obtained. Next rotate the tube until this Hne passes exactly through the intersection of the crossed lines of the instrument, making sure the temperature has become constant. Finally read the refractive index through lens L and record both this and the temperature. If the temperature varies from 40° or 25° (T), as the case may be, correct the reading R' a.t T' to a reading of R by the formula R=R' —0.000365 (T — T'). Leach and Lythgoe have devised a slide rule (Fig. 92), which not only converts the reading at one temperature to the reading at another, but also shows the butyro-refractometer readings corresponding to different refractive indices. The refractometer furnishes the simplest means of dis- 150 FATS AND OILS 3-4 3J i- ---n Ak Fig. 92. — Leach and Lythgoe Slide Rule for Refractom- eter Calculations. tinguishing olive oil, butter, and lard from imitations. The limits given in the table on p. 143 serve to distinguish olive oil from cotton seed and sesame oil. Wolny finds that the refractive index of the fat of pure butter at 25° C. ranges from 1.4590 to 1.4620 and of oleomargarine containing no real butter from 1.4650 to 1.4700. Lard, as given in the table on p. 143, has a refractive index at 40° C. of 1.4584 to 1. 460 1, while compound lard as found by the author shows a range of from 1.4606 to 1.4639. ^Detection of Cotton Seed Oil by the Halphen Test. Olive oil was formerly extensively adulterated with cotton seed oil. Compound lard and other lard substitutes commonly con- sist largely of cotton seed oil and oleo- margarine often contains cotton seed oil in addition to other fats. The Halphen test ^ is carried out as follows: Place in a test-tube about 5 cc. of the oil or melted fat and the same volume of Halphen reagent, con- sisting of a mixture of equal volumes of carbon bisulphide, containing in solution I per cent of sulphur, and amyl alcohol. Mix and heat in a bath of boiling saturated brine for fifteen minutes. If cotton seed oil is present a deep red color is formed. The constituent of the oil that gives the color, the identity of which has ^Analyst, 1897, p. 326. SESAME OIL BY THE BAUDOUIN TEST 151 not yet been established, is destroyed or driven off by heating at 2^ to 270° C. (Holde and Pelgry, Fulmer), but oil thu treated is not likely to be used. The amyl alcohol is useful because it contains pyridin (Gastaldi). ^ ^ ^ .- t. Another quahtative testis that first proposed by Bechi. It depends on the reduction of silver on heating the oil with a solu- tion of silver nitrate in a mixture of alcohol and ether acidulated with nitric acid. This test is not entirely satisfactory as rancid and overheated oils and fats not containing cotton seed oil often give a slight reduction. MiUiau obviates this difficulty by apply- ing the test to the fatty acids separated by saponification %Detection of Sesame Oil by the Baudouin Test. Sesame oil is used as a substitute for and adulterant of ohve oil. ^ The addition of a small amount of sesame oil to oleomargarine is required by the laws of certain European countries so that the food inspector will readily be able to distinguish the product from butter by means of a sunple quahtative test. Apply the Baudouin test^ to samples of oUve and sesame oil as follows: . 4. 4.^ a Dissolve 0.1 gram of cane sugar in 10 cc. of concentrated hydrochloric acid in a test-tube, add 20 cc. of the oil to be tested, and shake thoroughly for one minute. Allow to stand until he oil rises. If sesame oil is present to the amount of i per cent, the aqueous solution will become deep red. , , . f Certain pure African oUve oils are said to give a color,but o a different shade from that obtained with sesame oil. In doubtful cases the test may be applied to the fatty acids. The test depends on the reaction of a minor constituent of the oil with the furfural formed by the action of the acid on the sugar. ViUavecchia and Fabris^ employ an alcoholic solution of furfural instead of sugar. ^ Other Qualitative Tests. Tolman's modification of Renard s test for peanut oil,^ based on the separation of arachidic acid, is iZtschr. angew. Chem., 1892, p. SOQ- 2 Jour. Soc. Chem. Ind., 1894, P- i3- 3 U. S. Dept. Agr., Bur. Chem., Bui. 77- 152 FATS AND OILS useful in the examination of olive oil. Palm oil used as a coloring for oleomargarine is detected by tests devised by Crampton and Simon. 1 Various tests are in use for detecting artificial colors, such as sulphur, annatto, carotin, and oil-soluble coal-tar dyes, in butter. Beef stearin, a common ingredient of lard substi- tutes, is detected by modifications of Belfield's microscopic test. ^Determination of Iodine Number by the Hanus Modifica- tion of the Hiibl Method. The formation of halogen addition compounds of the glycerides of the unsaturated acids occurring in fats has already been noted (p. 140). The determination of the iodine number serves to measure the degree of unsaturation. Two factors, involving the constitution of the fat, influence the results, (i) the nature of the unsaturated acids present, those with two double bonds absorbing a greater percentage than those with the same number of carbon atoms but with only one double bond, and (2) the molecular weight of the glycerides, those with low molecular weights absorbing a greater per- centage than those of the same degree of saturation with high molecular weights. Of these factors the former is by far the most important. For example linseed oil has a very high iodine number (about 175), due to the presence of a considerable amount of linolic acid with two double bonds, while cocoanut oil, which consists largely of saturated acids, has a very low number (less than 10). The original method of determining iodine number devised by Hiibl, which for many years was exclusively used, employed a solution of iodine and mercuric chloride in 95 per cent alcohol. This solution deteriorated so rapidly in strength that after a few days it was useless, furthermore it acted so slowly on the fat that three hours' standing was required for the absorption of the iodine. Both of these defects are obviated by the solutions proposed by Hanus ^ and by Wijs, the former now being more generally used in the United States and the latter in England. The Wijs solution consists of iodine chloride dissolved in glacial 1 Jour. Amer. Chem. Soc, 1905, 27, p. 270. ^Ztschr. anal. Chem., 1901, 4, p. 913. IODINE NUMBER 153 acetic acid. Hanus in his modification of the Wijs solution employs iodine bromide. Reagents: (i) Iodine Solution. Dissolve 13.2 grams of pure iodine in i liter of pure 99 per cent acetic acid and when the solution has cooled add 3 cc. of bromine. After the addition of the bromine the halogen content, as determined by titration against thiosulphate solution, should be nearly but not quite doubled. (2) Decinormal Sodium Thiosulphate Solution. Dissolve exactly 24.8 grams of the c. p. crystallized salt in water and make up to I liter in a graduated flask. Unless the salt is impure or moist, which has never happened in the author's experience, the solution will be of the proper strength and further standardizing will be merely confirmatory. The solution may be standardized by iodine, by potassium iodate, or by potassium bichromate. The iodine method, which is the oldest and in the author's experience the most accurate, is as follows: Tare a short glass tube, such as is used for weighing out the fat (Fig. 93), together with a microscopic cover glass; place in the tube about 0.2 gram of c. p. resublimed iodine, heat cautiously until the iodine melts, close with the cover glass, cool in a desiccator, and weigh. Dissolve the iodine in 15 cc. of 10 per cent potassium iodide solution, dilute with water, and add thiosulphate solution from a burette with stirring until only a yellow color remains, then add a little starch paste and con- tinue the addition until the blue color is discharged. One cc. of the iodine solution should be equivalent to 0.0127 gram of iodine. (3) Starch Paste. Mix i gram of starch with 200 cc. of water, boil for ten minutes, and cool. (4) Potassium Iodide Solution. Dissolve 100 grams of the salt in water and make up to i liter. Manipulation. Weigh a flat-bottomed glass cylinder about 10 mm. in diameter and 15 mm. high (Fig. 93). Transfer to the cylinder by means of a glass tube from 0.15 to i.o gram of the oil or melted fat, the quantity used being such as to absorb not more than 40 per cent of the iodine present in 30 cc. of the 154 FATS AND OILS iodine solution. Use about (but no more than) 0.15 gram of olive, cotton seed, peanut, sesame, or rape oil, 0.25 gram of lard, 0.3 gram of beef or mutton tallow, 0.4 gram of butter fat or cocoa butter, and i .0 gram of cocoanut oil. Weigh the cyhnder containing the oil or fat, in the latter case after cooling to room temperature. Because of the small quantities em- ployed the weighing of the cylinder, both before and after adding the material, should be performed with the highest degree of accuracy which is possible because of the small size of the cylin- ders and the non-hygroscopic character of the fatty ma- terials. No desiccator need be used. By means of a pair of for- ceps carefully introduce the cylinder and contents into a glass-stoppered bottle of about 300-cc. capacity, add 10 cc. of chloroform and, after complete solution is effected, introduce 30 cc. of the iodine solution with great care by means of a pipette. Shake gently and allow to stand in a dark place with occasional shaking for thirty minutes. Add 15 cc. of potassium iodide solution and 100 cc. of water, then titrate slowly with standard thiosulphate solution, depend- ing for an indicator first on the yellow color of the Hquid and finally, when that has nearly disappeared, on the blue color obtained by adding a little starch paste. When the titration is nearly finished, stopper the bottle after each addition of thiosulphate, and shake to remove the iodine from the chloro- FiG. 93. — Iodine Number Apparatus. In- troducing cylinder with fat into bottle. Cylinder natural size at right. SAPONIFICATION NUMBER 155 form. In addition to duplicate analyses two blank determina- tions should be performed in exactly the same manner, using only the reagents. In calculating the results subtract from the average number of cubic centimeters of thiosulphate solution, obtained in closely agreeing blank determinations, the number of cubic centimeters obtained in each actual analysis, and multiply the difference by 0.0127, thus obtaining the grams of iodine absorbed. To obtain the percentage of iodine absorbed, which is the iodine number, multiply the grams of iodine absorbed by 100 and divide by the weight of material employed. ^Determination of the Saponification Number by the Koetts- torfer Method. This number ^ is a measure of the average molecular weight of the mixed glycerides constituting a given fat or oil. Although the range is not nearly so great as that of the iodine number, the saponification number is an important constant, particularly in distinguishing rape, mustard, and other cruciferous oils from most of the other edible oils, in identifying cocoanut oil, and in an exhaustive examination of butter sus- pected of sophistication. Reagents, (i) Alcoholic Potassium Hydroxide Solution. Dis- solve 30 grams of c. p. potassium hydroxide in i liter of 95 per cent alcohol, previously purified by standing some days with potassium hydroxide and distillation. The solution is approx- imately half-normal. (2) Standard Half-Normal Hydrochloric Acid Solution. — Prepare in the usual manner and standardize as described on p. 70. Process. Weigh accurately an Erlenmeyer flask of about 200-cc. capacity, introduce 2 to 2.5 grams of the oil or melted fat (1.5 to 2 grams of butter or cocoanut fat), and weigh again. Add 25 cc. of the alcoholic potassium hydroxide solution, con- nect with a reflux condenser, and boil gently, by heating over a piece of asbestos paper, for thirty minutes (Fig. 94). Cool, add a few drops of phenolphthalein solution as an indicator, and 'Ztschr. anal. Chem., 1879, p. 199. 156 FATS AND OILS titrate the excess of alkali with standard half-nonnal acid solu- tion. Conduct two actual analyses, then two blanks in exactly the same manner. It is immaterial whether the quantity of potash solu- tion discharged from the pipette is exactly 25 cc, but of great importance that the quantity is the same in all cases. Care must, therefore, be taken to use the same pipette and allow it always to drain for exactly the same length of time. In calculating the re- sults subtract from the average number of cubic centimeters of half-nor- mal acid, obtained in closely agreeing dupli- cates, the number ob- tained in each actual analysis, multiply the re- sult by 28.06 (the number of milligrams of KOH corresponding to each cubic centimeter of half- normal acid), and divide the product by the weight of material em- ployed. The Koettstorfer or saponification number thus cal- culated represents the number of milligrams of potassium hydroxide necessary to saponify completely i gram of the material. Fig. 94. — Saponification Number Apparatus. VOLATILE FATTY ACIDS 157 ^Determination of the Volatile Fatty Acids by the Leffmann and Beam Modification ^ of the Reichert-Meissl Method. This process is used chiefly in distinguishing oleomargarine from butter. It depends on the presence in butter fat of a consid- erable amount of glycerides of the fatty series with low carbon content, notably butyric acid (C4HSO2), whereas the fats and oils used in butter substitutes, known collectively as oleomar- garine, contain only small amounts if any. These acids are volatile on distillation with steam and are also quite soluble in water. Reichert was the first to make use of these facts in a method for detecting oleomargarine. The process was later improved by Meissl and later still by Leffmann and Beam, the latter employing for saponification a mixture of glycerol and sodium hydroxide instead of alcoholic sodium hydroxide solution. Polenske,^ in 1904, further modified the process so as to determine the volatile acids insoluble, as well as those soluble, in water, thus differentiating cocoanut oil, which contains a considerable amount of glycerides of these insoluble volatile acids, from butter. The following figures illustrate the value of both determinations: Butter fat, 31 samples, (Polenske). Cocoanut oil, 4 samples (Polenske) Oleomargarine fat (Arnold) Lard (Arnold) Tallow (Arnold) Reichert-Meissl Number. 23 ■ 3-30 ■ I 6.8- 7.7 0-3S 0.55 Polenske Number. i-s- 30 16. 8-17. 8 0-S3 o-S 0.56 By referring to the table on p. 140, it will be noted that butter contains acids with four to fourteen atoms of carbon and cocoanut oil, acids with six to fourteen atoms, both inclusive. It should be further noted that butter fat contains a consider- able amount of the acid with four atoms of carbon (butyric), ^ Analyst, 1891, p. 153. 2 Arbeit a. d. Kaiserl. Gesundheitsamte, 1904, p. 545. 158 FATS AND OILS which is not found in cocoanut oil, while cocoanut oil contains considerable amounts of acids with twelve and fourteen atoms (lauric and myristic) which occur only in small quantities in butter fat. Since the solubility decreases as the number of carbon atoms increases, it is obvious why butter fat gives a high Reichert-Meissl number and cocoanut oil a high Polenske number As cocoanut oil is not so commonly used in American oleomargarine as that made in Europe, only the soluble volatile acids or the Reichert- Meissl number need be determined by the stu- dent. Single determina- tions should be made on both butter fat and oleo- margarine fat prepared as described on p. 142. Method. Weigh accu- rately a 300-cc. Jena flask, introduce as much of the melted fat as will be delivered by a clean, dry 5-cc. pipette, and enough more to bring the weight up to about 5 grams. Allow to cool and weigh accurately flask and fat. Add 20 cc. of glycerine and 2 cc. of a solution prepared by dissolving 100 grams of c. p. sodium hydroxide, free from carbon- ates, in 100 cc. of boiled water. Heat cautiously on a piece of asbestos paper until the fat is saponified, which requires about five minutes and is indicated by the clearing up of the boiling Fig. 95.- -Distillation Apparatus for Volatile Fatty Acids. POLENSKE NUMBER 159 liquid. While still hot add very cautiously, at first, drop by drop, to prevent foaming, 90 cc. of boiled water and shake until the soap is dissolved. The solution should be perfectly clear and nearly colorless. Rancid or oxidized fats that yield a brown soap should not be examined. To the soap solution add 50 cc. of dilute sulphuric acid (25 cc. to I liter), and about 0.5 gram of granulated pumice stone with grains i mm. in diameter, then connect with a condenser, such as shown in Fig. 95, and distill at a rate sufficient to give a dis- tillate of no cc. in about twenty minutes, using a stream of water that will cool the condensed liquid to about 20° to 30°. Cool in water of about 15°, make up to the mark, mix by invert- ing the flask four or five times, filter through an 8-cm. dry filter, and pipette 100 cc. of the filtrate into a beaker. Titrate with tenth-normal alkali, using a few drops of phenolphthalein solu- tion as an indicator. If exactly 5 grams of fat were used the number of cubic centi- meters of standard alkali required multiplied by i.i is the Reichert-Meissl number, otherwise calculate to that amount. Determination of the Polenske Number. In this determina- tion (which for reasons already stated may be omitted), the condenser tube, flask, and filter, after obtaining the Reichert- Meissl number, as described in the preceding section, are washed with three 15-cc. portions of water and the insoluble volatile acids dissolved by the same treatment, using 15-cc. portions of neutral 90 per cent alcohol. The united alcohoUc washings are finally titrated as in the determinations of the soluble acids. Other Constants of Fats and Oils. The Melting-point of Fats ^ is determined in a capillary tube similar to that used for crystalHne substances except that it is open at both ends, the melted fat being drawn up into the tube and allowed to soUdify (Fig. 96). After twelve hours' cooling the tube is attached by a rubber band to the bulb of a delicate thermometer and both are suspended in a test-tube of water supported in a flask also containing water (Fig. 96). 1 Leach's Food Inspection and Analysis, p. 480. 160 FATS AND OILS The flask is gradually heated until the fat melts. The Maumene Test ^ is the measure of the rise of heat with sulphuric acid, which is highest with oils containing the greater percentages of unsaturated acids and, therefore, having the highest iodine numbers. The Bromination Test is similar to the last in principle, bromine being used instead of sulphuric acid. Another physical test is the solidifying point of the fatty acids, known as the Titer Test, determined by the Dalican method. Most of the tests designed primarily for the oils or fats them- selves may also be determined on the fatty acids liberated by a min- eral acid after saponification. Nat- urally the results are not the same as those obtained by the direct determination. Among the chemical tests is the estimation of the Soluble and In- soluble Fatty Acids. In the method for the determination of the Reichert-Meissl number the separation of the insoluble acids as an oily liquid, after addition of sulphuric acid to the saponified fat, is evident. The method for determining the soluble and insoluble acids also involves saponification and sep- aration of the acids with a mineral acid. The soluble acids are determined by titration; the insoluble acids by direct weighing of the washed and cooled oily layer. The method is now of comparatively small importance. The method for estimating the Acetyl Value, first proposed by Benedict and later modified by Lewkowitsch, depends on the substitution of the hydrogen of the alcoholic hydroxyl group ' Comptes rendus, 1852, 35, p. 572. Fig. 96. — Melting-point Appa- ratus for Fats. HYDROGENATION OF OILS 161 by the acetic acid radicle on heating with acetic anhydride, the acetylated fat being subsequently saponified and the acetic acid separated and titrated. Fats and oils contain, in addition to glycerides, very small amounts of U nsaponifiable Matter such as Cholesterol and Si- tosterol. The former is found m animal, the latter in vegetable fats. Hydrogenation of Oils. The hardening of the oils by hydro- genation, using nickel or some other metalHc catalyzer, is now- practiced on a commercial scale, cotton seed and other vege- table oils being thus changed into hard fats by the conversion of the olein into a saturated glyceride such as stearin. This treatment takes the place of adding to oils a hard fat such as stearin for the purpose of imitating the consistency of lard and other semisolid fats. It also adds to the list of edible oils, whale oil, which is not only hardened, but freed from rank-tasting impurities. This process changes materially the constants of the oil, thus increasing greatly the difficulties in interpreting the results of analvses. CHAPTER VIII FRUITS, FRUIT PRODUCTS, LIQUORS, AND VINEGAR In ascertaining the food value of fruits and vegetables, as well as their products, the percentages of water, fat, fiber, pro- tein, ash, and nitrogen-free extract, determined by practically the same methods as are used for grain, seeds, and their products, are of first importance. Sugars. Determmations of sugars are of special value in the examination of fruits as sucrose and invert sugar, the former being largely transformed into the latter during ripening, are usually present, contributing to the immediate food value and furnishing the material for alcohoUc fermentation of the fruit juices in the manufacture of wines and ciders and for the subse- quent acetous fermentation in the manufacture of vinegar. Sweetened fruit products, such as preserves, jeUies, and fruit syrups, contain sucrose and invert sugar as their chief constit- uents, which are determined by the same methods as are used in the analyses of sugar, molasses, and other cane and beet products. Acids. As all succulent fruits contain one or more organic acids, such as malic, citric, and tartaric, which, in the case of vinegars, are supplemented by acetic acid, no analysis of a fruit product is complete that does not include the amount of acidity. Estimating this acidity by titration with a standard alkali solution does not differentiate between the different acids, although, in many cases, the chemist knows the acid present in a given product to the practical exclusion of all others, thus permitting the use of the proper factor for the calculation of the percentage of that acid from the volume of standard alkali solution employed. For example, the acidity of vinegar would 163 164 FRUIT PRODUCTS, LIQUORS, AND VINEGAR be calculated as acetic, disregarding the small amount of malic acid in cider vinegar and of tartaric acid or cream of tartar in wine vinegar, and the acidity of lime juice would be calculated as citric acid. Starch, Oil, and Fiber. A few fruits, notably the Danana, are distinctly starchy, although at full maturity the starch passes largely into sugar, and one common fruit, the olive, is very oily. Most fruits, however, contain only small amounts of these constituents. Fruit juices are not only free from starch and oil, but also from crude fiber, therefore the analysis of the juices and of the liquors and vinegars made from them would not include determinations of these three constituents. Alcohol and Other Constituents. The labor saved in omitting analyses for starch, oil, and fiber in liquid products is offset by the need of determining alcohol in alcoholic liquors and acidity in most fruit products as well as of a number of substances present in small amount in liquors and vinegars which, although of little or no food value, serve as indications of strength and purity. The calculation of the alcoholic strength of liquors from the specific gravity of the distillate is of great value in industrial work and in the enforcement of excise and adulteration laws. Solids. While in dry products such as flour, meal, and cattle foods there is no ocular indication of the presence of moisture, in liquid fruit products there is no appearance of solid matter. We accordingly give the results in the former case in terms of mois- ture, in the latter in terms of total solids or extract. In juices the extract consists largely of sugar, which disappears almost en- tirely on fermentation. "^Laboratory Practice. The purpose of the two laboratory exercises which follow is partly to aid the student in a practical understanding of a few important analytical processes and partly to show how these processes are applied in scientific and technical investigations, having in mind the formation of alcohol from sugars and of acetic acid from alcohol with the consequent disappearance of most of the solid matter. PRACTICE MATERIAL 165 Material for Practice. As representative fruit juices either sweet cider or grape juice may be selected, both products being obtainable bottled and sterilized. Fermented cider sampled after the escape of carbon dioxide has ceased or an unsweetened wine, such as claret, will serve as a suitable alcoholic beverage, and either cider or wine vinegar as an acetified liquid. The most interesting sets of samples are those made from the same lot of apple or grape juice, the sterilized juice, the cider or wine, and the vinegar being bottled at the suitable time. Lacking these the ordinary commercial products will answer. It is recommended that products of the same fruit, either apple or grape, be analyzed by the same student. In most sections of the United States the apple series will be most readily obtainable and the three products can be kept in bottles for years. The student should carry on determinations of solids and acidity, also tests for sugar, in the three products of the series, on the first day. On the second day he can give his attention largely to the determination of alcohol. All the results should be calculated as grams per loo cc, which is approximately the same as grams per loo grams or true percentage by weight. The average of several analyses of each of the three products follows: Average Composition of Apple Juice, Fermented Cider, AND Cider Vinegar .dumber of Analy- ses Aver- aged. Solids. Total Sugar as Invert. Malic Acid. Acetic Acid. Alcohol. Ash. Apple juice (Browne) . . Fermented cider (Browne) lO 4 22 13.21 2.46 2.49 11.72 0.40 0.25 0.73 0.25 0. II 0.34 4.84 5-40 0.28 0.26 Cider Vinegar (Lythgoe) 0.34 166 FRUIT PRODUCTS, LIQUORS, AND VINEGAR Fruit Juices ^Determination of Total Solids. The determinations of chief importance are of sohds, sugars, and acidity. As the solids consist largely of sugars, fruit juices may be regarded as dilute sugar syrups and the solids may be approximately estimated from the specific gravity or the refraction, using certain tables which have been prepared for the purpose. These methods have the advantage of rapidity, and the inaccuracy, due to the presence of solids other than sugar such as organic acids, is offset by the inaccuracies of a gravimetric determination due to the difficulty of removing all the water on the one hand and the decomposition of levulose during heating on the other. This latter error is obviated by drying in vacuo at 70° C, but the process is tedious and requires special apparatus. For many purposes drying in an open dish at 100° for a conventional time is satisfactory, the decomposition not being sufficient to affect the general conclusions. In this connection it may be stated that a method may not have the highest degree of scientific accuracy and yet be quite as useful for certain purposes as if it were absolutely exact. This is because it is often the relative rather than the absolute results that are desired, and also because by experience the analyst learns to interpret his analyses in terms of yield of alcohol or acetic acid by the commercial process. Method. Weigh a flat-bottom tinned lead or aluminum dish such as is used in determining milk sohds (p. 15), introduce 5 cc. of the juice measured from a pipette, evaporate on a water bath to dryness, making sure that the liquid is distributed over the bottom of the dish, and dry in a water oven at the temper- ature of boiling water for two and one-half hours. Cool in a desiccator and weigh. All this can be done in a single labor- atory period. Calculate the weight of sohds in 100 cc. of the juice. If drying dishes or oven capacity are insufficient for duplicate determinations, one will answer. The process is so simple that errors of manipulation are not probable, further- SUGAR IN FRUIT JUICES 167 more the results of the diflferent students should check each other. Carry along determinations on the fermented cider and vinegar by the same method and at the same time. ■^Determination of Sugar. The sugar in a fruit juice freshly expressed is usually a mixture of sucrose and invert sugar, the latter being formed from the former during ripening. Further change of the sucrose to invert sugar goes on in the juice during storage and is accelerated during sterilization, consequently the sugar in the samples of sweet cider and grape juice used for laboratory practice, especially if sterilized, may consist entirely of invert sugar. In order to be certain of complete inversion, treatment with acid is necessary preliminary to copper reduc- tion, but for our purpose it will be sufi&cient to boil for two minutes i cc. of the fruit juice directly with 50 cc. of water and 25 cc. each of copper sulphate and alkaline Rochelle salts solutions (p. 76), noting that a copious precipitate of copper suboxide is formed. Should the student have opportunity the quantitative determination may be carried out as follows: Method. Pipette 5 cc. of the cider or grape juice into a loo-cc. graduated flask, dilute with about 50 cc. of water, and add lead subacetate solution (p. 133), drop by drop, until with shaking a precipitate no longer forms. Dilute to the mark, shake, and filter through a dry filter into an Erlenmeyer flask. To the filtrate add dry powdered potassium oxalate with shaking until all the lead is precipitated. Filter through a dry filter into a small Erlenmeyer flask. Pipette 50 cc. of the filtrate and 25 cc. of water into a graduated loo-cc. flask, add 5 cc. of concen- trated hydrochloric acid, and invert in a water bath kept at 72° to 73°, exactly as described on p. 131. Cool, add sodium hydroxide solution until shghtly alkaline to litmus paper, then add hydrochloric acid drop by drop until the paper turns red, make up to the mark, and shake. If the solution is not entirely clear, filter through a dry filter. Determine the copper-reducing power of 50 cc. of the solu- 168 FRUIT PRODUCTS, LIQUORS, AND VINEGAR tion by the Munson and Walker method as described on p. 76, except that the weight of invert sugar, corresponding to the copper suboxide, should be found in the table (pp. 213 to 221), and the weight of this sugar in 100 cc. of the original cider or juice calculated. A comparison should be made of the results obtained for solids and sugars. ^Determination of Acidity. Of the non-sugar solids, organic acids and ash are the chief constituents. Determine the acidit}' by titrating 25 cc. of the cider or juice with tenth-normal sodium hydroxide solution. For the cider use as indicator a few drops of phenolphthalein solution (i gram in 100 cc. of alcohol), for the grape juice, so-called neutral litmus paper. Titrate also the fermented cider or wine and the vinegar at the same time, using for the vinegar only 10 cc. Wine, Cider, and Other Liquors Fermentation. Grape must, cider, and other fruit juices ferment through the action on the invert sugar of the enzyme Zymase of the wild yeast plants Saccharomyces ellipsoideus, S. apiculatus, etc., which naturally occur on the outside of the fruit and find their way into the expressed fruit juices, the reaction being as follows: C6Hi206 = 2C2H60-F2C02. Dextrose or Alcohol Carbon levulose dioxide In the manufacture of malt liquors the conversion of starch into the soluble carbohydrate Maltose is first effected by means of Diastase, the enzyme of malt, then the maltose is hydrolized by means of an enzyme in yeast, known as Maltase or maltoglucase, with the formation of dextrose as follows : 2C6Hio05+H20 = Cl2H220ll Starch Maltose C12H22O11 +H2O = 2C6H12O6. Maltose Dextrose FERMENTATION 169 For the fermentation of malt liquors yeast of the species Saccharomyces cerevisicE is added. In making lager beer a strain known as bottom yeast (Fig. 97) is used while for ale top yeast (Fig. 98) is necessary. Liebig regarded fermentation as a purely chemical process Fig. 97,. — Bottom or Beer Yeast. Budding plants. (Lindner.) and ignored the biological theories of Pasteur and others which have since been accepted. Krober by his classical researches has more recently shown that the ferments of yeast may act without the intervention of the growth of the cells, Fig. 98. — Top, Ale, or Distillery Yeast. Budding plants. (Lindner.) thus returning in a sense to the purely chemical theories of Liebig. The carbon dioxide formed during fermentation is either allowed to escape or else, as in the case of malt liquors and 170 FRUIT PRODUCTS, LIQUORS, AND VINEGAR effervescent wines, is confined, at least in part, by tight casks or corked bottles. Natural wines cannot contain more than i8 per cent of alco- hol, as the yeast plant ceases to grow after that strength has been reached. By adding alcohol, fortified wines, such as sherry and port, are obtained and by distillation any desired alcoholic strength can be secured. Cognac or French brandy is the distillate from wine, cider brandy, from fermented cider, whiskey and gin, from fermented grain infusions, and rum, from diluted and fermented molasses. Theoretically over 51 per cent of invert sugar is obtainable as alcohol, but practically under the most favorable conditions the yield is less than 49 per cent, the remainder going to form glycerol, succinic acid, and various higher alcohols which make up the fusel oil of distilled liquors. Analysis of Liquors. In addition to alcohol, the character- istic constituent of all fermented and distilled liquors, the fol- lowing minor constituents are determined: Wines and Ciders. Extract or sohds, sugars, acids (fixed and volatile), tartaric and malic acids (free and combined), glycerol, potassium sulphate (used in plastered wines), sodium chloride, nitrates, tannin, preservatives, and colors. Malt Liquors. Extract, sugars, dextrin, glycerol, acids (fixed and volatile), protein, phosphoric acid, added bitter principles and preservatives, and arsenic (introduced in glucose made with impure acid). Distilled Liquors. Extract, acids, esters, aldehydes, fur- fural, fusel oil, added wood alcohol, and caramel (added for coloring) . The complete analysis of a liquor is a laborious task, but such an analysis is not ordinarily necessary except in special cases as in detecting adulteration, in tracing the cause of certain defects, or as a guide in special manufacturing problems. The Composition of the most important wines, malt liquors, and distilled hquors appears in the following tables: COMPOSITION OF WINE AND OTHER LIOUORS 171 Average Composition of European Wines (Koenig) Results expressed as grams per loo cc. Alcohol. Extract. Total Acidity as Tartaric. Volatile Acids as Acetic. Sugar. Gly- cerol. Ash. Phos- phoric Acid. Claret. 8.16 8.12 9.48 16.09 10.42 2.42 2.91 3 03 4.06 2.36 0.58 0.77 0.66 0.41 0.61 0. 10 0.05 0.09 0.23 0.23 0.84 2.40 053 0-73 0.8s 0.97 0.71 0.25 0. 20 0.25 0.46 0. 14 0.029 0.045 0.032 0.028 Rhine wine Sauterne Sherry Champagne (dry) Average Composition of Malt Liquors (Koenig) Alcohol by Weight. Extract. Acid as Lactic. Gly- cerol. Ash. Phos- phoric Acid. Nitro- genous Sub- stances. Sugar as Maltose. Lager beer Bock beer Ale Porter 3-93 4.69 4-75 4.70 5-79 7. 21 5.6s 6-59 015 0.17 0.28 0.28 0.17 0.18 0.23 0.26 0.31 0.36 0.077 0.089 0.086 0.093 0.71 0-73 0.61 0.65 0.88 I. 81 I .07 2.62 Composition of Distilled Liquors Whiskey : Scotch, 8 yrs. old. . Irish, 7 yrs. old . . . Rye, 4 yrs. old .... Bourbon, 4 yrs. old Imitation rye Cognac, 10 yrs. old. . Rum Gin Neutral spirits Analyst. vasey Vasey Crampton and Tolman Ladd Vasey Vasey Vasey Ladd ftoJ < Grams per 100 Liters of Proof Spirits. 185.0 151-9 S06 . 1 1 Acids. 6S S8 7J 37-2 14.0 0.0 3.8 44.8 5 69 -3 53-5 5-7 54-6 199.5 18.7 14.0 5.6 13.9 II .0 trace 8.3 4.2 o.g 3-2 100. o 102.0 125.1 123.9 46.9 62. 1 45.3 22.3 14.8 ' Includes caramel color. 172 FRUIT PRODUCTS, LIQUORS, AND VINEGAR ■^Determination of Alcohol. The method of determination is the same for all kinds of alcoholic liquors except that the addi- tion of O.I to O.I 2 gram of calcium carbonate or standard alkali to neutral reaction is necessary if the wine or cider has partly turned into vinegar and only 25 grams or cc. of distilled liquors and cor- dials are employed. Method. The distilla- tion apparatus used for de- termining the volatile fatty II Fig. 99. Fig. 100. Fig. 99.-=—/ Pycnometer; // Delivery Tube. Fig. 100. — Alcohol Distillation Apparatus. acids (Fig. 95) is suitable except that a delicate pycnometer (Fig. 99, /), is substituted for the wide-mouthed receiving flask and the condenser tube is connected at the lower end by means ALCOHOL IN LIQUORS 173 of a rubber tubing with a delivery tube (Fig. 99, 77), the lower part of which is of such a size that it readily passes through the neck of the pycnometer. The height of the pycnometer should be such that it can stand erect on the balance pan and the inside of the neck should be 5 mm. It is calibrated to contain 100 grams of water at 15.5° C. Fig. 100 shows the complete apparatus for alcohol determination set up ready for use. If the liquor is effervescent pour from one glass to another until no more bubbles of carbon dioxide escape. Weigh the clean, dry pycnometer, introduce the delivery tube, and attach the latter to the condenser tube. Pipette 100 cc. of the sample into a 300-cc. flask, add 50 cc. of water and a little tannic acid to prevent frothing. Attach to the condenser, turn on the water, heat cautiously to boiling, and continue to boil until the pyc- nometer is filled nearly to the bottom of the neck. Detach the delivery tube, rinse with a few drops of water, and mix by shak- ing. Add water nearly to the graduation mark and place in a bath of water at 15.5°, taking care that the water covers the pycnometer to the height of the liquid within. After standing in the bath at least fifteen minutes, remove the pycnometer, without delay add water at 15.5° by means of a small pipette until the lower meniscus is exactly at the mark, dry off the out- side surface, and weigh. Subtract from the total weight the weight of the empty pyc- nometer, thus obtaining the weight of the distillate, which divided by 100 gives its specific gravity. In the table on pp. 226 to 230 find the grams of alcohol per 100 cc. corresponding to the specific gravity, which is the common way of expressing the result in wine analysis, also the percentage of alcohol by vol- ume and by weight in the distillate. As the volume of the sample and of the distillate are both 100 cc, the grams of alcohol per 100 cc. and the percentage by volume in both are the same. To obtain the percentage by weight multiply the weight of the distillate by the percentage of alcohol by weight contained in it and divide by the weight of the sample obtained either by a direct weighing of 100 cc. or from the specific gravity. 174 FRUIT PRODUCTS, LIQUORS, AND VINEGAR ^Determination of Solids (Extract). As is true of fruit juices the extract in sweet wines (sherry, port, etc.), cannot be determined with absolute accuracy by drying at ioo°, owing to the decomposition of levulose. In the case of claret, Rhine wine, and others containing less than 3 per cent of extract, 50 cc. may be evaporated to dryness in a fiat-bottomed dish 85 mm. in diameter and dried for two and one-half hours at 100° C, as prescribed by the German ofl&cial method. In the analysis of the fermented cider or light wines selected for laboratory practice satisfactory results may be obtained by evaporating ic cc. of the wine or cider in a tinned lead or alum- inum dish 65 mm. in diameter, such as is used for milk soHds, and drying two and one-half hours at 100° C. This work is carried out in connection with the determination of solids in the juice and the vinegar. "^Determination of Acidity. Total acidity is found by the same method as is used for sweet cider or grape juice and vinegar. Volatile Acidity is valuable in wine analysis, as it is a measure of souring or incipient acetous fermentation. The process con- sists simply in distilling a portion of the wine and titrating the distillate. This need not be carried out by the student. Vinegar Kinds of Vinegar. Any alcoholic liquor of suitable dilution may be subjected to acetous fermentation for the manufacture of vinegar. On the Continent Wine Vinegar is commonly made from white or red wine, the former being the better. In Eng- land Malt Vinegar is preferred, while in the United States Cider Vinegar is regarded as the standard product. Owing to the high price of cider vinegar and the increased demand, large quantities of Distilled Vinegar are now made from dilute alcohol, the process being carried on in conjunction with the manufacture of compressed yeast. While the distilled product is quite as strong as cider vinegar, it is lacking in ethers and other flavoring constituents and contains only a very small VINEGAR 175 amount of sugar, phosphates, and other solids, glycerol and other constituents characteristic of vinegar made from fer- mented liquors. Sugar Vinegar or Molasses Vinegar and Glucose Vinegar are made in considerable quantities. Dilute acetic acid obtained by purifying pyroligneous acid from the dry distillation of wood is not regarded as suitable for food. Analyses of different kinds of vinegar appear in the table on p. 176. Process of Manufacture. Mycoderma aceti, the bacterium which converts the alcohol into acetic acid (Fig. loi), is widely distributed and the spores are likely to find their way into the barrels of cider or other liquor stored with open bungholes in the farmer's cellar. The proc- ^^^ ,^,._vinegar Bacteria, Mycoderma aceti. ess is commonly accel- (Fischer.) erated by adding the slimy growth known as " mother of vinegar" from a barrel containing vinegar already made or in process of making. Farmer's or barrel-fermented vinegar requires two or three years for developing its full acid strength, owing partly to unfa- vorable temperatures, but chiefly to insufficient contact with the oxygen of the air, acetous fermentation, unlike alcoholic fermen- tation, being an oxidation process, as shown by the following equations : (1) C2H60-fO = C2H40+H20 Alcohol Aldehyde Water (2) C2H40+0 = C2H402. Aldehyde Acetic acid Quick-process or generator vinegar is made by allowing the cider to drip through beech shavings, previously soaked in old vinegar, contained in a cask or vat through which passes a current of warm air. By carefully regulating the conditions the vinegar is formed in a few days. 176 FRUIT PRODUCTS, LIQUORS, AND VINEGAR Composition of Vinegar. The following table gives the average composition of cider, wine, malt, and distilled vinegar: Average Composition or Different Kinds of Vinegar Kind of Vinegar. Number Samples Ana- lyzed. Acidity as Acetic Acid. Organic Acid other than Acetic. Total Solids. Sugars. Ash. Phos- phoric Acid (P2O6). Cider (Lythgoe) Wine (Koenig) Malt (Hehner) Distilled (Paris Munici- pal Lab.) 22 17 7 4.84 5-57 4 23 6.34 O. II 0.13 2.49 1.89 2 . 70 0.35 0,25 0-35 trace 0-34 o. 27 0-34 0.04 0035 0053 0.105 ' Malic, free and combined. - Tartaric, free and combined. From the figures in the table it is evident that distilled vin- egar is readily distinguished from cider, wine, and malt vinegars by the low percentages of total solids and ash. As a safeguard against adulteration with distilled vinegar, as well as dilution, the Federal standard and the laws in certain states require that cider vinegar contain at least 4 grams of acetic acid and 1.6 grams of solids in 100 cc. But a minimum figure for solids alone does not suffice, as boiled sweet cider can readily be added in sufficient amount to bring the percentage of solids above the limit. To prevent this fraud, the standard requires that the sohds contain not more than 50 per cent of reducing sugars, and also fixes the minimum percentages of ash, phosphoric acid, and alkalinity of ash. To illustrate, i part of sweet cider containing over 13 per cent of sohds, the average of Browne's results (p. 165) mixed with 7 parts of distilled vinegar would contain over 1.60 per cent of solids, but the amount of sugar in the solids would greatly exceed 50 per cent; furthermore the minimum limits for ash, phosphoric acid, and alkahnity of ash would not be reached. Frear, who suggested the ratio of sugars to total solids as required in the above standard, also pointed out the importance of the SOLIDS AND ACIDITY IN VINEGAR 177 ratio of ash to total solids. Naturally this ratio is much less in sweet cider or in distilled vinegar mixed with sweet cidei than in cider vinegar. A certain amount of glycerol is also a char- acteristic of cider and wine vinegar as well as of the fermented liquors from which they are made. The analyses made by Ross, by Bender, and by Goodenow have established 0.24 per cent of glycerol as the minimum for generator vinegar. The distinction of wine and malt vinegars from other kinds is not so important in the United States as in Europe. Wine vinegar is characterized by the presence of tartaric acid, free and combined as cream of tartar (potassium bitartrate) or in other combination, whereas the non- volatile acid of cider vine- gar is largely malic. Malt vinegar usually contains more solids and phosphoric acid than cider or wine vinegar and is also char- acterized by the presence of dextrin and maltose. Glucose vinegar and molasses or sugar vinegar are relatively of small importance. The former is dextro-rotatory both before and after inversion, the latter is dextro-rotatory before but levo- rotatory after inversion. Cider vinegar is invariably levo- rotatory. ^Determination of Solids and Acidity in Vinegar. See pp. 166 and 168. The determination of other constituents need not be taken up in this short course. They are of interest chiefly in food inspection. Various Fruit Products A great variety of food products formerly prepared only in the household are now made and put up in suitable containers in large establishments. Among the best known are canned fruits, dried fruits, preserves, jellies, catsup, and mince-meat. Methods of Analysis. The products named may be anal- yzed by the methods described in Chapter IV and on the foregoing pages of this chapter, introducing slight modifica- tions when needed. Preservatives. Only two chemical preservatives are now used to any considerable extent in fruit products made in the 178 FRUIT PRODUCTS, LIQUORS, AND VINEGAR United States. These are, (i) Sulphur Dioxide, employed in bleaching as well as preserving dried fruits, and (2) Sodium Benzoate, added to preserves, jellies, catsup, and mince-meat. Sulphur dioxide is determined by the method described for meat products containing sulphites (p. 38), sodium benzoate by Dunbar's modification of the La Wall and Bradshaw method. The latter method depends on the extraction of the benzoic acid by chloroform after adding common salt to hold back certain interfering substances. The benzoic acid is weighed and in addition may be titrated in an alcoholic solution. CHAPTER IX FLAVORING EXTRACTS Food, in the restricted sense, includes only such products as furnish the body with materials for the production of mus- cular energy, heat, or the repair of tissues; in the broader sense it includes products used solely for their flavor, such as spices and flavoring extracts, or for their flavor and stunulating properties, such as tea and coffee. Proteins and fat in a state of purity have little or no flavor and the same is true of starch and dextrins of the carbohydrate group. Sugars are the exception among the nutritive substances in that they have pronounced flavors. The flavor of most natural or manufactured foods is due to minor constituents produced in the animal or vegetable organism^ or else developed by roasting or other method of preparation. When the flavor is lacking or needs modifying, spices, extracts, or similar materials are used. Distinction of Spices from Extracts. Spices are natural products used solely for their flavoring constituents. Although they consist chiefly of the substances belonging to the six groups considered in Chapter IV, their flavoring power, due to minor constituents, is so great that they are used in quantities too smafl to aid appreciably in nutrition. The valuable ingredients are essential oils and other pungent or aromatic bodies. Often the flavor is a blend resulting from the presence of two or more constituents. Most flavoring extracts are alcohoHc solutions (tinctures) of essential oils such as oil of lemon, orange, almond, clove, cinnamon," nutmeg, peppermint, or wintergreen. Vanilla extract, however, contains vanillin, a crystalline substance, and various other aromatic substances derived by direct extraction of the dried fruit. 179 180 FLAVORING EXTRACTS Nature of the Analytical Methods. In the determination of the essential oil in lemon and orange extract a centrifugal method, employing the Babcock apparatus, and a polariscopic method, involving the technique described in the chapter on sugars (p. 131), are used. Vanillin and coumarin are determined gravimetrically in vanilla extract and substitutes by extraction with immiscible solvents and vaniUin is also estimated color- imetrically. Citral, one of the flavoring constituents of lemon and orange extract, is also determined by a colorimetric method. The analysis of extracts accordingly furnishes varied experience and the methods are typical of many others devised for the analysis of various materials including, not only foods but drugs and other technical products. The experience of carrying on two processes at the same time is also valuable. In this connection it should be reiterated that the purpose of this book is not to describe a great number of tedious processes regardless of variety or importance, but rather a carefully selected number illustrative of types, striving at the same time to give a general idea of the subject of food analysis and the composition of foods. Too often the student is staggered by page after page of dry description and fails to grasp the subject as a whole or to appreciate its absorbing interest and practical importance. Vanilla Extract and Substitutes Vanilla Beans. The term bean is a misnomer, as the product is not the seed of a legume, but the fruit of an orchid {Vanilla planifolia). The narrow pods when taken from the plant are green and about the size and length of a lead pencil, but on drying become black and much shriveled (Fig. 102). They con- tain great numbers of black seeds so minute that they form a powder. The world's supply comes chiefly from Mexico, the insular possessions of France off the coast of Africa (Bourbon or Reunion, Madagascar, etc.). South America, and Tahiti, the market value diminishing in the order named. The better sorts sell for several dollars a pound. They contain, according to analyses by Win ton and Berry, from 1.50 to 3.50 per cent of VANILLA EXTRACT AND SUBSTITUTES 181 vanillin, also other aromatic constituents not yet isolated which although present in small amount, contribute materially to the delicate flavor. Vanillin (CgHgOs) is the methyl ether of protocatechuic aldehyde. It may be obtained as white crystalline needles either by extraction of vanilla beans with ether or other solvents, or synthetically by the oxidation of the eugenol of oil of cloves with alkaline potassium perman- ganate. The synthetic product has sold as low as 35 cents per ounce, whereas if made from vanilla beans it would cost ten to twenty times that amount. In other words only from one- tenth to one-twentieth of the cost of vanilla beans can properly be attributed to their vanillin content, the remainder being paid for the other flavoring constit- uents. Tonka Beans (Fig. 103) are the seeds of a tree {Dipterix odoratd) native to Guiana. As the tree belongs to the Leguminosce the seeds are appropriately termed beans." They resemble almonds in size and shape. The chief flavoring constituent is coumarin. Coumarin (C9HCO2) is the anhydride of coumaric acid. Coumarin is also found in sweet grass {Anthoxanthum odoratum) much used in Indian basket work, sweet clovers of the genus Mellilotus, and sweet woodruff (Aspenda odoratd). It is prepared synthetically from salicylic alde- hyde, sodium acetate, and acetic anhydride. The flavor of coumarin, although somewhat similar to that of vanillin, is less agreeable. Vanilla Extract. Tincture or extract of vanilla contains the Tonka Fig. 102. — Vanilla Bean. 182 FLAVORING EXTRACTS ingredients of the vanilla bean soluble in 60 per cent alcohol and added cane sugar. It is, therefore, quite complicated in its composition and belongs in a different class from most flavoring extracts such as almond, peppermint, wintergreen, cinnamon, cassia, cloves, and nutmeg, which are merely alcoholic solutions of essential oils. In addition to vanillin, vanilla extract contains brown coloring matter and other substances forming a flocculent precipitate with normal lead acetate solution, resin, organic acid, and certain ash constituents. The formula of a former edition of the United States Phar- macopoeia for the preparation of vanilla extract is as fol- lows : " Vanilla, cut into small pieces and bruised, 100 grams. " Sugar, in coarse powder, 200 grams. " Alcohol and water, each, a sufficient quantity to make 1000 cc. " Mix alcohol in the proportion of 650 cc. of alcohol to 350 cc. of water. Macerate the vanilla in 500 cc. of this mixture for twelve hours, then drain off the liquid and set it aside. Transfer the vanilla to a mortar, beat it with the sugar into a uniform powder, then pack it in a percolator, and pour upon it the reserved liquid. When this has disappeared from the surface, gradually pour on the menstruum, and continue the percola- tion, until 1000 cc. of tincture are obtained." Vanilla extract prepared according to this formula varies according to Winton and Berry between the following limits: Vanillin, o.io to 0.35 gram per 100 cc. Normal lead number, 0.40 to 0.80. Per cent of color in lead filtrate, not more than 10 per cent red or 1 2 per cent yellow. Ratio of red to yellow in the extract, not less than i : 2.2. Color insoluble in amyl alcohol, not more than 40 per cent. The range in acidity and ash was found by Winton, Albright, and Berry to be as follows: Total acidity, 30 to 52 cc. N/io alkah per 100 cc. PRACTICE MATERIAL 183 Acidity, other than vanillin, 14 to 42 cc. N/ 10 alkali per 100 cc. Total ash, 0.220 to 0.432 gram per 100 cc. Substitutes for Vanilla Extract. Synthetic vanillin, tonka beans, and synthetic coumarin are much used in the preparation of flavoring solutions designed as substitutes for or imitations of vanilla extract. As both vanillin and coumarin are colorless, caramel is commonly added to these solutions in sufficient amount to impart a deep coffee color to the liquid. Such preparations, although often containing percentages of vanillin within the limits for vanilla extract, are characterized by their low normal lead number, low acidity other than vanil- lin, low ash, low ratio of red to yellow color in the extract, high percentages of color, both in the lead filtrate and insoluble in amyl alcohol. Coumarin, which is absent in vanilla extract, is often present. ■^^Materials for Laboratory Practice. The analysis of a genuine vanilla extract and a substitute, consisting of a solution of vanillin and coumarin colored with caramel, will give the student sufficient experience for an understanding of the most important methods and the interpretation of results. The vanilla extract can either be prepared in the laboratory accord- ing to the U. S. P. formula or may be obtained of a reputable manufacturer. The substitute may be prepared by dissolv- ing 2 to 4 grams of vanillin, 0.4 to i.o gram of coumarin, and 200 grams of sugar in a mixture of equal parts of 95 per cent alcohol and water, adding sufficient caramel to impart a deep coffee color, and making up to i liter with the same menstruum. Care should be taken that the amount of caramel added is not sufficient to impart a color too deep to be conveniently measured by the Lovibond tintometer. The composition of the vanilla extract can be learned only by analysis, whereas the precentages of vanillin and coumarin in the substitute will be known, at least to the instructor, from the quantities used. At least 57 cc. of each preparation should be available for each student, 50 cc. for the gravimetric analysis, 184 FLAVORING EXTRACTS 5 cc. for the volumetric determination of vanillin, and 2 cc. for determining the color value. Only single determinations need be made on each material by the methods described. The results for vanillin by the two methods should check each other, thus serving as duplicates, and the single gravimetric analysis in the case of the vanilla extract will demonstrate the absence of coumarin quite as well as duplicates. The estimation of the color value involves such simple manipulation as to preclude the probabihty of error. The single result for coumarin in the vanilla substitute and the single results for normal lead number in both materials ordinarily would require checking, if only a single analyst were involved, but for our purpose a comparison of the results of the different students will suffice. It may here be reiterated that agreeing results by the same analyst are often not conclusive, as he is liable to make the same error in both determinations. In important work it is desirable that the duplicates be made by different analysts and if possible with different reagents and apparatus, thus elimi- nating the personal equation. ^Determination of Vanillin and Coumarin by the Modified Hess and Prescott Method. This process, in its original form devised by Hess and Prescott, has been modified by the author, collaborating with Silverman, Bailey, Lott, and Berry, in order to prevent loss of coumarin, detect the presence of acetanihde (formerly much used as an adulterant of vanillin), and permit the determination of normal lead number in the same weighed portion.^ It depends on the principle that ammonia water, acting on the ether solution of vanillin and coumarin, forms with the aldehyde vanillin a compound soluble in water, but does not affect the coumarin, which remains in solution in the ether. Extraction with Immiscible Solvents. This method is par- ticularly instructive, as it is a type of numerous methods involv- ing the extraction of one or more constituents from an aqueous ' Jour. Amer. Chem. Soc, 1899, 21, p. 256; U. S. Dept. Agr., Bur. Chem., Bui. 152, p. 147 VANILLIN AND COUMARIN 185 liquid with an immiscible solvent such as ether, chloroform, or carbon bisulphide. Various forms of apparatus for the con- tinuous extraction of one liquid with another have been devised, but for ordinary purposes shaking in a separatory funnel, as here described, is preferable. Care must be taken to avoid too violent shaking with ether, as otherwise an emulsion will be formed which is not easily broken up. The ether should always be poured out of the neck of the funnel after drawing off the Fig. 104. — Squibb Separatory Funnel. aqueous liquid through the stopcock, thus obviating contamina- tion with the water-soluble constituents such as the sugar of the extract or the ammonium chloride formed by the neutrali- zation of ammonium hydroxide. Fig. 104 shows the pear-shaped or Squibb form of separatory funnel, which is well adapted for the analysis of vanilla extract. The support has holes with slots for inserting the separatory funnels, but may be used also for ordinary funnels. Process. Pipette 50 cc. of the extract directly into a tared 250-cc. beaker with marks made with diamond ink showing vol- 186 FLAVORING EXTRACTS umes of 80 and 50 cc; dilute to 80 cc. with water boiled until free from carbon dioxide, and evaporate to 50 cc. in a pan of water kept at 70° C. by a Bunsen burner. Dilute again to 80 cc. and evaporate to 50 cc. as before. Transfer to a loo-cc. grad- uated flask, rinsing the beaker with hot carbon dioxide-free water, taking care not to use more than 25 cc; add 25 cc. of standard lead acetate solution (80 grams of chemically pure crystallized lead acetate dissolved in water and made up to i liter), make up to the mark, shake, and place in a bacteriological incubator, in a water bath provided with a thermostat, or in other suitable apparatus, kept at a temperature of from 37° to 40° C. Two laboratory periods of four hours each will be required for the work up to this point. During the first of these periods, while the dealcoholizing is proceeding, there will be time to determine vanillin by the Folin and Denis method (p. 192). The color value of the vanilla and vanilla substitute (p. 189) can be determined during the second period; the glass dishes for the vanillin and the coumarin can also be weighed. On the third day, after the flask has been kept at 37° to 40° for eighteen to twenty hours, filter through a small dry filter and pipette off 50 cc. of the filtrate into a Squibb separatory funnel of 125 cc. capacity. For the determination of normal lead number, pipette off 10 cc. of the filtrate into a beaker and precipitate as described on p. 191. Use the remainder of the lead filtrate for the deter- mination of color value (see p. 190). This can be carried out while the vanillin and coumarin are being shaken out with ether. If kept until the next day a cloudiness, due to absorption of carbon dioxide and precipitation of lead carbonate, is liable to appear. To the 50 cc. of the filtrate in the separatory funnel add 20 cc. of ether and shake cautiously several times. Draw off carefully through the stopcock the aqueous liquid, together with any ether emulsion, and then pour the clear ether solution from the mouth into a beaker. Return the aqueous solution to the separatory funnel and shake out as before using, however, VANILLIN AND COUMARIN 187 15 cc. of ether. Repeat this treatment twice. Reject the extracted aqueous hquid and rinse the separatory funnel. Pour the combined ether solutions into the rinsed separatory funnel, add 10 cc. of 2 per cent ammonium hydroxide solution, and shake several times. Draw off the ammoniacal solution into a beaker, taking care not to allow any of the ether solution to pass through with it. Shake out with three more portions of the ammonium hydroxide solution exactly as before, except that 5 cc. are used. Transfer the ether solution, containing the coumarin if present and from which the vanillin has been removed in the ammoniacal solution, to a weighed low- form, glass crystallizing dish, 60 mm. Iflljjl^ jlH in diameter, with an etched circle on which is placed an identification mark with a lead pencil (Fig. 105). Add to the combined ammoniacal _ _^=^„^„_^ solutions with stirring 10 per cent hydro- chloric acid until it is slightly acid to test ^^' ^°^' Y)- P^ ^ '^'^"^ paper. This should be done without delay, as the ammoniacal solution on standing grows slowly darker with a loss of vanillin. Cool, transfer to the separatory funnel and shake out the vanilUn with four portions of ether, as described for the first ether extraction, removing the ether solution each time to a weighed crystallizing dish. Allow the ether in this crystallizing dish, as well as that in the crystalliz- ing dish containing the ethereal solution of the coumarin, to evaporate at room temperature until the next day. Do not attempt to hasten the evaporation of the ether by heating or by an air current, as this will cause condensation of moisture in the dishes, owing to the lowering of the temperature. On the following day (the fourth of the work on extracts), place the crystallizing dishes in a sulphuric acid desiccator, then finish the determination of normal lead number as described on P- 191- On the fifth day weigh the dishes containing the vaniUin 188 FLAVORING EXTRACTS and coumarin and calculate the weight per loo cc. of each. The genuine vanilla extract will, of course, contain no coumarin. although a very small amount of resinous material may be obtained which, were it crystalline and present in considerable amount, would be considered coumarin. In the vanilla substitute the crystals of coumarin are recog- nized by their needle shape and characteristic odor. Deter- mine the melting-point as described below and subject the re- mainder to the Leach test (p. 189). The identification of the coumarin is essential, as its presence constitutes an adulteration in a preparation purporting to be pure vanilla extract. At one time synthetic vaniUin was often adulterated with acetanilide, which, by the process above described, would be' largely weighed with the coumarin but could be subsequently separated. ^Determination of the Melting-point of Coumarin. The melting-point, so often determined in the organic laboratory, serves for the identification of many crystalline substances. The required apparatus is the same as that used for deter- mining the melting-point of fats (Fig. 96), except that the flask and tube are smaller and the capillary tubes are closed at the lower end. Instead of water, concentrated sulphuric acid is used. Introduce a crystal or two of the substance into a capillary tube closed at one end and place this against the bulb of the thermometer where it adheres owing to the viscosity of the acid. Slowly heat the acid in the flask over a Bunsen burner. The heat is communicated to the acid in the inner tube and finally to the substance in the capillary tube. Note the temperature at which the crystal melts. To make capillary tubes suitable for melting-point deter- minations, heat the middle part of a test-tube and draw down to the size of the lead in a pencil, cut into lengths of about i| in., and close one end of each, by fusing. The melting-point of pure coumarin is 67° C. That obtained in the analysis may melt slightly below that temperature, as any impurity depresses the melting-point. The variation from 67° should, however, not be more than a degree or two. COUMARIN TEST; COLOR VALUES 189 Leach Test for Coumarin. To the portion of the crystals remaining in the crystaUizing dish (p. i88), add a few drops of water, warm gently, and add a few drops of a solution of iodine in potassium iodide. In the presence of coumarin a brown precipitate will form which, on stirring with the rod, will soon gather in dark-green flocks. ^Determination of Color Value of Vanilla Extract and Sub- FiG. 1 06. — Lovibond Tintometer. stitutes. The Lovibond Tintometer (shown in Fig. 106), is a simple instrument so arranged that light is reflected from a square of opal glass R, through a cell with glass sides C, con- taining the liquid under examination, and at the same time through standard colored glass slides S, added, one by one, to a carrier until the colors, as seen through an eyepiece 0, match. The standard slides used in general work are red, yellow, and 190 FLAVORING EXTRACTS blue in even graduation from .006 to 20 tint units, which can be combined so as to produce any desired tint or shade of any color. The results are expressed in terms of standard dominant colors (red, yellow, and blue), subordinate colors (orange, green, and violet), obtained by combining equal values of two dominant colors, and neutral tint (black), obtained by combining equal values of the three dominant colors. Thus o.6i? + 5.67=o.60+5.oF, o.o8i?+i.5F+o.25 = o.o8iV+o.i2G+i.3F, i.2R-\-i.oB = i.oVi-o.2R in which R=red, F= yellow, 5= blue, 0= orange, G= green, V = violet, and N = neutral tint or black. For vanilla extract work only the following 17 slides are needed : Red, 5.0, 2.0, 2.0, i.o, 0.5, 0.2, 0.2, 0.1, Yellow, lo.o, 5.0, 2.0, 2.0, 1.0, 0.5, 0.2, 0.2, 0.1. It is recommended, however, that a set of blue slides of the denominations given for the red be provided for the highly instructive study of colors and color combinations. Process. Pipette 2 cc. of the extract into a 50-cc. graduated flask and make up to the mark with a mixture of equal parts of 95 per cent alcohol and water. Determine the color value of this diluted extract in terms of red and yellow by means of a Lovibond tintometer, using the i-in. cell. To obtain the color value of the original extract multiply the figures for each color by 25. For example, a reading of 0.6 red and 2.1 yellow obtained on the diluted extract corresponds to a color value of 15 red and 52 yellow calculated to the original extract. ^Determination of Residual Color after Precipitation with Lead Acetate. As soon as possible after filtration determine the color value, in terms of red and yellow, of the filtrate from the lead acetate precipitate, obtained in the determination of NORMAL LEAD NUMBER 191 vanillin and coumarin (p. i86), using the i-in. Lovibond cell. Multiply the reading by 2, thus reducing the result to the basis of the original extract. In case the actual reading of the solution is greater than 5 red and 15 yellow, as may happen if the extract is highly colored with caramel, the |- or i-in. ceU should be employed and the readings multiplied respectively by 4 or by 8; or else 10 cc. of the solution should be diluted to 50 cc. in a graduated flask, mixed, examined in the i-in. cell, and the readhig multiplied by 10. Divide the figures for red and yellow respectively, by the corresponding figures of the original extract and multiply the quotients by 100, thus obtaining the percentages of the two colors remaining in the lead acetate filtrate. For example, if the color value of the original extract is 15 red and 52 yellow and the color value of the lead acetate filtrate, also measured in the i-in. cell, is 0.6 red and 2.4 yellow, then the residual color, after precipitation with lead acetate, calculated to the basis of the original extract, is 1.2 red and 4.8 yellow or 8 per cent of the red and 9.2 per cent of the yellow. ^Determination of Normal Lead Number by the Winton and Lett Method. Mix the 10 cc aliquot of the filtrate from the lead acetate precipitate, obtained in the determination of vanil- lin and coumarin (p. 186), with 25 cc. of water, boiled until free from carbon dioxide, and a moderate excess of sulphuric acid. Add 100 cc. of 95 per cent alcohol and mix again. Let stand overnight, collect the lead sulphate on a weighed Gooch crucible, wash with six portions of 95 per cent alcohol, filling the crucible each time and allowing it to empty before adding the next portion, dry at a moderate heat on a piece of asbestos paper, ignite at low redness for three minutes, takmg care to avoid the reducing flame, cool, and weigh. The normal lead number is calculated by the following formula: 5 192 FLAVORING EXTRACTS in which P = normal lead number, 5 = grams of lead sulphate corresponding to 2.5 cc. of the standard lead acetate solution as determined in blank analyses, and IF = grams of lead sul- phate obtained in 10 cc. of the filtrate from the lead acetate precipitate as above described. The standard of the lead acetate solution is determined by- blank analyses and does not change appreciably on standing in a well-stoppered bottle. The beginner probably will not find time to determine the standard and can accept the figures obtained by the instructor or the more advanced student. The normal lead number of the genuine extract should vary between the limits given (p. 182), while that of the substitute will be practically zero, ^Determination of Vanillin by the Folin and Denis Method. This method^ is based on the fact that vanillin (as well as other mono-, di-, and tri-hydric phenol compounds), when treated in an acid solution with phosphotungstic-phosphomolybdic acid, gives on addition of an excess of sodium carbonate, a beautiful deep blue color. It yields accurate results, requires but 5 cc. of the material, and is exceedingly rapid. An analyst familiar with the process can make ten or twelve determinations in an hour, whereas, working under favorable conditions, he would not be able to make the same number of determinations by the Hess and Prescott method in less than three days. For inspec- tion purposes the latter method has the advantage that the vanillin and coumarin are obtained in crystalline form for sub- sequent tests; furthermore coumarin, normal lead number, and color value of the lead filtrate are determined in one weighed portion. Given the reagents, the student will have no difficulty in making determinations of vanillin in the practice samples (p. 183), by the Folin and Denis method, while waiting for the dealcoholizing required in the Hess and Prescott method. It may here be mentioned that it is often necessary for the analyst, in order to use his time to the best advantage, not only to carry ^ Jour. Ind. Eng. Chem., 1912, 4, p. 670. CALORIMETRIC ANALYSIS 193 along together determinations by the same method on dif- ferent samples, but also in the intervals to have in progress analyses by entirely different methods. Nature oj Colorimetric Methods. The Folin and Denis method is typical of nmnerous colorimetric methods in that it depends on the formation of a colored compound with the sub- stance to be determined, the amount present being estimated from the intensity of the coloration of the solution as compared with that of a solution containing a known amount of that substance treated in the same manner. The solution of the unknown may either be compared with several solu- tions, prepared with different amounts of a standard solution, selecting for the calculation the one that matches in shade, or else it may be compared with a single solution, varying the height of the column of one or the other until the colors reflected through the two columns match and calcula- ting the result by the rule of three. The former procedure is used in de- termining the free and albuminoid ammonia in potable water by a process known as " Nesslerizing," while the latter is more commonly employed in food analysis. The comparison of the solution of the unknown with the standard may be made in two tubes, each provided with a stopcock at the bottom whereby a portion of the darker solution may be drawn off until the two columns match in tint or else a colorimeter may be used. The Schreiner Colorimeter is well adapted for our purpose, being inexpensive, of simple construction, and accurate. This apparatus, shown in Fig. 107, consists of two graduated tubes Fig. 107. — Schreiner Colorimeter. 194 FLAVORING EXTRACTS B, containing the standard and unknown colorimetric solutions, the height of the column of liquid in both tubes being changed by two immersion tubes A, which remain stationary while the graduated tubes are raised or lowered in the clamps C. The mirror D reflects the Hght through the tubes, and the mirror E reflects it again to the eye of the operator at F. In making the comparisons the tube containing the solution of either known or unknown strength is set at a definite point, and the other tube is raised or lowered until the colors match. If R is the reading of the standard solution of the strength 5, and r the reading of the colorimetric solution of unknown strength s, then R^ r If desired, standard slides of colored glass, such as accom- pany the Lovibond tintometer, may be used at G for matching the solution of unknown strength, the value of these slides being determined by comparison with a standard solution. Suggestions. The student should not be discouraged if at first he has difficulty in securing concordant readings in the comparison of the two solutions in the colorimeter. Some expe- rience is required before the eye can detect slight differences in shade and arrive at the exact point where the two solutions match in color intensity. The following hints may prove helpful : Choose a soft but sufficient Hght, best at a north window or reflected from the north sky; never use direct sunlight. Prac- tice at first with the same solution in both tubes. Do not use too high columns, as it is difficult to match deep colors. Avoid straining the eyes; adjust the tubes rapidly until the colors match approximately, then look away and when the eyes have rested a moment make the final adjustment in about five sec- onds. Do not attempt colorimetric work when the light is poor, when the eyes are tired, or when you are hurried or other- wise mentally disturbed. VANILLIN BY COLORIMETRIC METHOD 195 Reagents, (i) Standard Vanillin Solution. Dissolve o.i gram of pure vanillin in water and make up to i Uter. (2) Phosphotungstic-phosphomolybdic Acid Reagent. To 100 grams of pure sodium tungstate and 20 grams of phospho- molydic acid (free from nitrates and ammonium salts) add 100 grams of syrupy phosphoric acid (containing 85 per cent H3PO4) and 700 cc. of water. Boil over a free flame for one and one-half to two hours, cool, filter, if necessary, and make up with water to I liter. An equivalent amount of pure molybdic acid may be substituted for the phosphomolybdic acid. (3) Sodium Carbonate Solution. Prepare a solution of the c.p. salt, saturated at room temperature. (4) Lead Solution. Dissolve 50 grams each of basic and neutral lead acetate in water and make up to i Uter. Process. Pipette 5 cc. of the extract or substitute into a graduated loo-cc. flask, add about 75 cc. of cold tap water and 4 cc. of lead solution, make up to the mark with water and shake. Filter rapidly through a folded filter paper and pipette 5 cc. of the filtrate, corresponding to 0.25 cc. of the extract, into a 50-cc. graduated flask. Into another 50-cc. graduated flask pipette 5 cc. of the standard vanillin solution, which volume contains 0.0005 gram of vanillin. To each flask add from a pipette 5 cc. of the phosphotungstic-phosphomolybdic reagent, directing the stream against the neck in such a manner as to wash down any adhering vanilUn. Shake the flasks by a rotary motion, allow to stand for five minutes, then fill to the mark with sat- urated sodium carbonate solution. Thoroughly mix the con- tents of the flasks by inverting several times and allow to stand for ten minutes in order that the precipitation of sodium phos- phate may be complete. Filter rapidly through folded filters and compare the color of the deep-blue solutions, which must be clear, in the colorimeter. In this, as in all colorimetric methods, a slight cloudiness of the solution of the unknown, by cutting off more light than the standard, gives a low reading and correspondingly high result. 196 FLAVORING EXTRACTS Calculate the grams of vanillin per loo cc. as follows: P = ^ = — o.2sr 5r in which P is the grams of vanillin per loo cc, R is the reading of the standard solution and r is the reading of the unknown solution in the colorimeter. Determination of Other Constituents. Sucrose is calculated from the polariscopic readings (p. 133), and Alcohol from the specific gravity of the distillate obtained by direct distillation as in the case of a liquor (p, 172). The amount of neither of these constituents throws any light on the genuineness of an extract; on the other hand, the percentage of Ash and the Acidity other than vanillin, as shown by Winton, Albright, and Berry, bear a striking relation to the normal lead number and are valuable in distinguishing genuine vanilla extract from solutions of vanillin and coumarin. The solubility and alkalinity of the ash serve to detect the presence of added alkali in vanilla extract. The total acidity is determined by titration, using phenol- phthalein as an indicator, the acidity due to vanillin by calcu- lation from the percentage of that constituent. Total ash is determined by evaporation and incineration at a dull red heat. Lemon Extract Lemon Oil is the essential oil obtained from lemon peel. The chief regions of production are Sicily and adjoining parts of the ItaHan mainland, where the manufacture of oil from the peel and citrate of hme from the pulp are carried on in the same factories. Commercial citric acid is obtained by heating citrate of lime with sulphuric acid. Limonene (CioHie), a dextro-rotatory terpene with a strong flavor, makes up about 90 per cent of lemon oil; Citral (CioHieO), an aldehyde with a delicate flavor and the characteristic odor of lemon peel is present to the extent of 4 to 5 per cent. Both LEMON EXTRACT 197 of these substances occur in the peel of other citrus fruits, and citral is also present in lemon grass. Commercial citral is obtained from lemon grass or artificially by the oxidation of geraniol. Limonene is soluble in strong alcohol, but insoluble in dilute alcohol, while citral is soluble in both. Lemon Extract as recognized by Federal and State standards, as well as by the trade, is a solution in strong alcohol of at least 5 per cent by volume of lemon oil, with or without the coloring matter and other extractive substances of lemon peel. When diluted with water, it becomes cloudy, due to the precipitation of the limonene. The flavor, aside from that of the alcohol, which evaporates in cooking or is lost by dilution, is a combina- tion of the strong taste of limonene and the delicate aroma of citral. Terpeneless Lemon Extract is a solution prepared by shaking lemon oil with dilute alcohol or dissolving so-called terpeneless lemon oil in that solvent and should contain at least 0.2 per cent, by weight, of citral. It is used for flavoring soda water and other liquids to which lemon extract would impart a turbidity. As under ordinary market conditions the cost of a lemon extract is due more to the alcohol than to the lemon oil, the cheaper ter- peneless extract is often sold for family use and has not always been labeled so as to show its true character. ^Material for Laboratory Practice. A lemon extract con- taining from 5 to 8 per cent of lemon oil dissolved in 95 per cent alcohol and a terpeneless extract containing 0.20 to 0.30 per cent of citral, prepared by dissolving i gram of terpeneless lemon oil in 300 cc. of 50 per cent alcohol, are suited for analytical practice. These may either be prepared in the laboratory or obtained from the manufacturer or grocer. Dilute a portion of the terpeneless extract with an equal volume of water. No cloudiness should appear, showing that lemon oil is not present and that a quantitative determination of this substance is unnecessary. Arrangement of Time. On the day when the vanillin and coumarin, obtained in the analysis of vanilla extract and sub- 198 FLAVORING EXTRACTS stitute, are weighed (p. 187), time will be found to determine lemon oil by Mitchell's two methods ^ in the lemon extract. As the polarization method involves no manipulation other than direct polarization and the centrifugal method serves as a check, a single determination by each method will suffice. Citral can be determined in both samples on the following day, after the extraction of caffeine from coffee has been started (p. 205). ^Determination of Lemon Oil by the Mitchell Polariscopic Method. Polarize the extract, without dilution, in a 200-mm. tube in the same manner as is described in Chapter VI. Divide the reading obtained in degrees Ventzke on the sugar scale by the factor 3.2. If sugar or other optically active substances are not present, as is almost always the case, the quotient will be the per cent of lemon oil by volume. ^Determination of Lemon Oil by the Mitchell Centrifugal Method. Pipette 20 cc. of the extract into a Babcock milk- test bottle (p. 19), add i cc. of dilute hydrochloric acid (1:1) and 25 to 28 cc. of water previously warmed to 60° C, mix, and let stand in water at 60° C. for five minutes, whirl in a centrif- ugal machine five minutes, as in milk analysis, fiU with water at 60° nearly to the 10 per cent graduation, and whirl again for two minutes. Immerse in water at 60° nearly to the top of the neck for a few minutes and finaUy read the length of the column exactly as in the Babcock test. When the result is over 2 per cent add 0.4 per cent to correct for lemon oil retained in the solution, when less than 2 per cent but more than i per cent, add 0.3 per cent. The result thus corrected should agree with that by the polarization method within 0.2 per cent. A marked disagreement by the two methods would indicate the presence of a foreign essential oil, such as oil of citronella, in which case the oil layer obtained in the test bottle should be examined as to its refractive index and other properties. For- tunately such addition is rarely, if ever, practiced. ^Determination of Citral by the Hiltner Method. This 'Jour. Amer. Chem. Soc, 1899, 21, p. 1132. CITRAL IN LEMON EXTRACT 199 colorimetric method ^ measures the strength of terpeneless lemon extracts and also detects the substitution in lemon extract of " washed lemon oil," the residual oil after shaking with dilute alcohol in the manufacture of terpeneless extracts, for natural lemon oil. A lemon extract made from washed lemon oil will naturally be deficient in citral. Reagents, (i) Metaphenylene Diamine Hydrochloride Solution. Prepare a i per cent solution in 50 per cent ethyl alcohol. Decolorize by shaking with fuller's earth or animal charcoal, and filter through a double filter. The solution should be bright and clear, free from suspended matter, and practically colorless. It is well to prepare only enough for the day's work, as it darkens on standing. The color may be removed from old solutions by shaking again with fuller's earth. This reagent gives a yellow color with citral but no appreciable color with the other aldehydes present in lemon extract or lemon oils. (2) Standard Citral Solution. Dissolve 0.25 gram of c.p. citral in 50 per cent ethyl alcohol and make up the solution to 250 cc. (3) Alcohol. For the analysis of lemon extracts 90 to 95 per cent alcohol should be used, but for terpeneless extracts 40 to 50 per cent strength is sufficient. Filter to remove any suspended matter. If not practically colorless, render sHghtly alkahne with sodium hydroxide and distill. Purification from aldehyde is unnecessary. Process. All the operations are carried out at room temper- ature. Weigh into a 50-cc. graduated flask 25 grams of the extract, make up to the mark with alcohol, and mix thoroughly. This diluted extract can be used by the whole class. Pipette into a 50-cc. graduated flask 2 cc. of the diluted extract (equiva- lent to I gram of the original extact), add 10 cc. of metaphenylene diamine hydrochloride solution, make up to the mark with alco- hol, and shake. Into another 50-cc. flask pipette 2 cc. of the standard citral solution (containing 0.002 gram of citral), add 10 cc. of metaphenylene diamine hydrochloride solution, make 1 Jour. Ind. Eng. Chem., 1909, i, p. 798. 200 FLAVORING EXTRACTS up to the mark with alcohol, and shake. Compare at once the color of the two solutions in the Schreiner colorimeter (p. 193). Calculate the result by the following formula: jj_0.002RXlOO _o.2R J-- _ ^ r r in which P is the per cent by weight of citral, R is the reading of the standard solution, and r is the reading of the unknown solution in the colorimeter. Determination of Other Constituents. Alcohol is deter- mined in a portion of the extract from which lemon oil has been removed by dilution, shaking with magnesium carbonate, and filtration. The oil which is precipitated by dilution is mechan- ically held by the magnesium carbonate, thus affording a clear filtrate. The alcohol is obtained from an aliquot of the filtrate by distillation and its amount calculated from the specific gravity. Total Aldehydes are estimated by a method devised by Chace, depending on the amount of color developed in a solution of the dye fuchsin, which has been decolorized by sulphur dioxide. Practically all the aldehyde content of lemon extract or terpeneless lemon extract is citral. Other aldehydes are present in orange extract. Neither the alcohol nor the total aldehydes need be determined by the student. Coloring Matter if of coal-tar origin is detected by the usual methods, if from lemon peel by Albrech's method. Analysis of Other Extracts. Orange Extract is analyzed by practically the same methods as lemon extract. Denis and Dunbar ^ have devised a method for the deter- mination of benzaldehyde, the chief constituent of Almond Extract, based on its precipitation as hydrozone with phenyl hydrazine. Hortvet and West - oxidize it to benzoic acid. Wintergreen oil is determined in Wintergreen Extract by the Hortvet and West method ^ depending on its conversion first ^ Jour. Ind. Eng. Chem., 1909, i, p. 256. 2 Ibid., p. 84. VARIOUS EXTRACTS 201 into potassium salicylate by boiling with potassium hydroxide and hydrogen peroxide solution and finally into salicylic acid by treatment with hydrochloric acid. Peppermint oil is determined in Peppermint Extract by C. D. Howard's modification ^ of Mitchell's centrifugal method. The essential oils in various Spice Extracts are estimated by methods devised by Hortvet and West ^ and CD. Howard.^ 'Jour. Amer. Chem. Soc, 1908, 30, p. 608. -Jour. Ind. Eng. Chem., 1909, i, p. 84. CHAPTER X COFFEE, TEA, AND COCOA Food Value of Alkaloidal Beverages. Coffee and tea are valuable solely because of their flavoring and stimulating prop- erties. A cup of either beverage has practically no food value except what is due to added milk, cream, and sugar. The quan- tity of the material used per cup is itself small and of this only a portion goes into solution in the water with which it is boiled or steeped; the remainder contained in the coffee grounds or spent tea leaves is rejected. Chocolate, as such, and after removal of a portion of the fat, in which form it is known as cocoa, on the other hand, is not merely a flavor and stimulant, but a concentrated food, rich in fat and protein and valuable also for its starch. The Stimulating Principles of alkaloidal beverages, Caf- feine and Theobromine, the former being present in all these, the latter only in cocoa and chocolate, have been shown by Emil Fischer to be purin derivatives, closely related to xan- thine. Their structural formulae, which follow, show them to be respectively tri- and di-methyl xanthine. NCCHs)— CO NH CO II II CO C— N(CH3)s. CO C— N(CH3)\ I II >CH I II ^CH NCCHs)— C W N(CH3)— C W Caffeine Theobromine NH— CO I I CO C— NH\ I II >CH NH— C W Xanthine 203 204 COFFEE, TEA, AND COCOA These bases are also grouped with the alkaloids. Formerly the principle of tea was known as theine, but more recently it has been shown to be identical with the caffeine of coffee. Caffeine is present in chocolate and cocoa in smaller amounts than theo- bromine. It is a remarkable fact that these stimulants are associated with flavors which are particularly acceptable to the human race and that of the tens of thousands of other plants not con- taining a stimulant none yields an infusion that attracts the appetite like these three " cups that cheer." Flavors by a strange psychological association lead man not only to the true elements of nutrition he needs, but also to the stimulants he craves. The Microscopic Structure of the three products (pp. ii8 to 122) should be kept constantly in mind in considering the analyses given in this chapter. The study of structure and chemical composition of natural vegetable products should always go hand in hand, one throwing light on the other. Coffee Composition of Coffee. The following table is based on analyses by Lythgoe ^ obtained on roasted samples of Santos, Porto Rico, Rio, Mocha, and Java coffees: Moisture Fat (petroleum ether extract Crude fiber Protein Caffeine Ash Nitrogen-free extract Hot water extract ^ . Average. 2 . 16 13-75 13 03 12 .00 1 . 20 403 53 83 100.00 25.80 Maximum. 3-44 15 18 14 75 13 75 I 34 4 38 55 72 27 70 Minimum. 1.26 12.28 II .02 10.50 I . 10 3-74 49.29 24.60 ^ Technology Quarterly, 1905, 18, p. 236. Other constituents were also deter- mined. 2 Calculated from the 10 per cent extract obtained by boiling one hour accord- ing to McGill's method. CAFFEINE IN COFFEE 205 From the above figures it will be seen that only about one- quarter of the coffee was extracted by boiling with water, the remainder being of no value to the consumer. In addition to the constituents given in the table coffee contains a tannic acid known as caffetannic acid. C. D. Howard found 1 1. 1 7 per cent of this acid in a sample of Java and Mocha coffee and Shanley 9.47 to 9.96 per cent in samples of Java, Mocha, and Rio coffee. Coffee Substitutes. Chicory, the root of a plant related to the dandelion, is frequently mixed with coffee, imparting a sweetish taste and a deep-brown coloration. It yields more extractive matter when boiled with water than coffee. Other Substitutes are made by roasting Barley, Malt, Wheat, Rye, Peas, Figs, Dried Bananas, Dried Beet Root, and various other products. Most of the substitutes sink when stirred with cold water, whereas coffee floats. Microscopic examination will usually dis- close the nature of the material provided it has not been roasted beyond recognition. Cereal products, peas, and bananas are rich in starch; chicory, figs, bananas, and beet root are rich in sugar. Neither starch nor an appreciable amount of sugar is present in coffee. ^Determination of Caffeine in Coffee by the Goiter Method. Material for Laboratory Practice. Powder a sample of coffee so it will pass a 25-mesh sieve. On this material determine caffeine in duplicate. The work requires three laboratory periods of four hours each, but during the first period, after the extraction has been started, there will be sufficient time to determine citral in the samples of lemon and terpeneless lemon extract (p. 198). No other analytical work need be done on coffee, tea, or cocoa, as most of the methods are those already used in the analysis of other products or are such as can be understood from a brief description. Process} Mix 11 grams of the powdered coffee with 3 cc. * Liebig's .\nnalen, 1908, 358, p. 327. 206 COFFEE, TEA, AND COCOA of water, allow to stand for thirty minutes, and place in the inner tube of a Johnson extractor. Should the tube be too small to hold the moistened coffee, use proportionately less of both the coffee and water. Connect an extraction flask (not weighed) and pour through the coft"ee sufficient chloroform to penetrate the mass and half fill the flask. Extract, as described on p. 56, for three hours. At the end of the extraction or on the next day, evaporate off the chloroform from the flask, taking care to avoid too \iolent ebullition with consequent mechanical loss. Treat the residue in the flask with 5- to lo-cc. portions of boiling water, filtering each time through a plug of cotton con- tained in the stem of a fmmel into a 55-cc. graduated flask. Cool to room temperature, make up to the mark, mix by invert- ing several times and pipette off 50 cc. (equivalent to 10 grams of the coffee) into a 125-cc. separatory funnel. Shake with four portions of 15 cc. each of chloroform, as described for vanilla extract (p. 1S6). As the chloroform, unlike ether, forms a layer below the aqueous liquid, it may be drawn off each time through the stopcock. Use for collecting the four portions of chloroform a weighed tinned lead, aluminum, por- celain, or glass dish, which can be kept at a gentle heat so that while shaking with one portion, the preceding portion can be evaporating. Finish the evaporation and dry in a boiling water oven for one hour, cool in a desiccator, and weigh. Repeat the heating for one hour and weigh again. If the weight is constant, calculate the percentage of dry residue, which should be practically pure caffeme. In very exact work the nitrogen in the residue should be determined and the caffeine calculated, using the factor 3.464, but for our purpose the result obtained from the weight of the residue is sufficiently accurate, pro\'ided due care has been taken in the manipulation. Other Methods for the Analysis of Coffee. The methods for the determination of Water, Fat, Crude Fiber, Total Xitrogen, and Ash are those described in Chapter IV. The per cent of Nitrogen as Calcine is obtained by multiplying the per cent of caffeine by the factor 0.2SS6. To obtain the per cent of Pro- TEA 207 tein subtract the caffeine nitrogen from the total nitrogen and multiply by 6.25. Cafetannic Acid is extracted by 90 per cent alcohol, precip- itated with lead acetate, and weighed, after drying at icx)° C. as lead caffetannate, by Krug's method.^ Tea Composition of Tea. Koenig - has compiled the results of 158 analyses of tea by different chemists with the following results: Average. Maximum. Moisture Nonvolatile ether extract. Essential oil Crude fiber Protein Theine (caffeine) Ash Tannin Nitrogen-free extract other than tannin 8.46 8.24 0.68 10.61 24- 13 2.79 5-93 12.35 26.81 Minimum. II 97 15 15 15 50 38 65 4 67 8 03 25 20 3 93 3 61 8 51 18 19 I 09 4 10 4 48 Kenrick ^ in the analysis of 53 samples of Chinese, Japanese, and Indian teas found that from 23.37 to 38.53 per cent of soHds were extracted by a ten-minute infusion. Coloring and Facing. Formerly green tea was colored by a blue pigment such as Prussian blue, ultramarine, or indigo, often with the addition of turmeric or some other yellow color, but the practice has now been largely discontinued. The pig- ments are readily seen in the siftings examined under a lens and their identity is established by simple micro-chemical tests. 1 U. S. Dept. Agr., Div. Chem., Bui. 13, p. 908. * Chemie der RIenschlichen Nahrungs- und Genussmittel. ' Canada Inland Revenue Dept., Bui. 24. 208 COFFEE, TEA, AND COCOA Facing of green tea with talc or clay and of black tea with plumbago and other black powders is also now seldom prac- ticed. Foreign Leaves and Spent Tea Leaves at one time were added to tea in the country of production. If a small handful of tea is brought to boiling with water and the leaves thus soft- ened are spread out on paper, the form, size, and dentation of the leaves can be noted (Fig. 79). At the present time such an examination will seldom, if ever, disclose foreign leaves, but it will serve to bring out the size and maturity of the leaves, and the presence of stems and similar impurities. The percentage of hot-water extract, as determined by a conventional method, was used to detect spent leaves. Analysis of Tea, The methods described in Chapter IV are applicable to tea. Caffeme is determined by direct weighing, as in the case of coflfee, but the details of the process are different due to the pres- ence of tannin and other interfering substances. One of the best processes is that of Stahlschmidt, as modified by AUen,i in which the tannin is precipitated from a water infusion by lead acetate and the excess of lead in the filtered solution is removed by precipitation with sodium phosphate previous to extraction of the caffeine. Tannin is estimated by oxidation with a standard solution of potassium permanganate, using indigo carmine as an indicator, as first proposed by Lowenthal and afterwards modified by Proctor.- Since other oxidizable substances are present it is necessary to make two titrations, one of the infusion directly to obtain the total oxidizable substances and another, after removal of the tannin by precipitation with gelatin. The difference be- tween the two titrations represents the tannin. ' Commercial Organic Analysis, 4th ed., Vol. VI, p. 607. ^ Jour. Soc. Chem. Ind., 3, p. 82. CHOCOLATE AND COCOA 209 Chocolate and Cocoa Composition of Cocoa Products. A summary of analyses of 17 varieties of unground Chocolate {Cocoa Nibs), made by Winton, Silverman, and Bailey ^ appears in the following table: Composition of Chocolate Average. Maximum. Minimum. Water Fat Crude fiber 2.72 50.12 2.64 1.04 0.40 12. 12 3-32 8.07 1957 3.18 52.25 3.20 1.32 0.73 13.06 4-15 8.99 21 .07 2. 29 48.11 2. 21 Theobromine Caffeine Protein 0.82 0. 14 II .00 Ash Starch Nitrogen-free extract other than starch 2.61 6.49 17.69 100.00 The composition of Cocoa is the same as that of the chocolate from which it was made allowing for the fat removed and, in the case of so-called Dutch cocoa, for the alkali added to aid in forming a more complete emulsion in the preparation of the beverage. Compounds of chocolate and cocoa with starch or flour are now unusual. Formerly they were sold fraudulently. Cocoa Shells are used for preparing a mild beverage. When ground to an impalpable powder they are said to be added to cocoa. Sweet Chocolate and Sweet Cocoa are mixtures containing sugar and often vanilla, vanillin, spices, or other flavors. Milk Chocolate contains milk powder and usually also sugar and flavoring. ' Conn. Agrl. Expt. Sta. Rept., 1902, p. 282. 210 COFFEE, TEA, AND COCOA Analysis of Chocolate and Cocoa. All the methods employed in the analysis of cereals and other natural vegetable foods, as described in Chapter IV, may be used for cocoa products. It should be noted, however, that the filtrations in the determina- tion of fat and fiber are very slow and the method for starch requires preliminary extraction of the fat by ether or gasohne and of sugars (if present) by water. Theobromine and Caffeine are determined by the Decker method.^ The material, together with calcined magnesia, is boiled with water and the liquid filtered. The filtrate is evap- orated to dryness and the residue extracted with chloroform. On evaporation of the chloroform a nearly pure mixture of the two alkaloids is obtained, which is weighed. Caffeine is removed from the mixture by benzol, in which theobromine is insoluble at room temperature. If a direct determination is desired the theobromine in the residue is treated according to Kunze's ^ method, based on the formation of silver theobromine when silver nitrate is added to an ammoniacal solution of the alkaloid. ' Schweiz, Wchshr. Pharm., 1902, 40, pp. 527, 541, 553. "Ztschr. anal. Chemie, 1894, 33, p. i. APPENDIX CALCULATION TABLES VIETH'S TABLE FOR CORRECTING QUEVENNE LACTOMETER READ- INGS FOR TEMPERATURE E egrees Degrees of Thermometer (Fahrenheit). of L actom- eter. 45 46 47 48 49 so 51 S2 S3 S4 55 S6 57 58 S9 60 20 »9-c 19.0 19. 1 19. 1 19.2 19.2 19-3 19.4 19.4 19-5 19.6 19.7 19.8 19.9 19.9 — 21 ...... 19-9 20.0 20.0 20.1 20.2 20.2 20.3 20.3 20.4 20.5 20.6 20.7 20.8 20.9 20.9 — 32 ...... 20. g 21. a 21.0 21. 1 21.2 21.2 21.3 21-3 21,4 21-5 21.6 21.7 21.8 21.9 21.9 — 23 21. 9 22.0 22.0 22.1 22.2 22.2 22.3 22.3 22.4 22.5 22.6 22.7 22.8 22.8 22.9 ' — 24 22-9 22.9 23.0 23.1 23.2 23-2 23-3 23-3 23-4 23-5 23.6 23.6 23-7 23.8 23-9 — 35 23.8 23-9 24.0 24.0 24.1 24.1 24.2 24-3 24.4 24-5 24.6 24.6 24-7 24.8 24-9 — 26 - 24^8 24.9 24.9 25.0 25-1 25-1 25-2 25-2 25-3 25-4 25-5 25.6 25-7 25-8 25-9 — 27 25-« 25-9 25-9 26.0 26.1 26.1 26.2 26.2 26.3 26.4 26.S 26.6 26.7 26.8 26.9 — 28 26.7 26.8 26.8 26.9 27-0 27.0 27.1 27.2 27-3 27-4 27-5 27.6 27-7 27.8 2.7.9 — 29 27.7 27.8 27.8 27.9 28.0 28.0 28.1 28.2 28.3 28.4 28.5 28.6 28.7 28.8 28.9 — 30 28. f 28.7 28.7 28.8 28.9 29.0 29.1 29.1 29.2 29.3 29-4 29.6 29-7 29.8 29-9 — 31 29-5 29.6 29.6 29-7 29.8 29-9 30.0 30.1 30.2 30-3 30-4 30-S 30.6 30.8 30-9 — 32 30-4 30.5 30-5 30.6 30-7 30-9 31.0 3I-I 31-2 31-3 31-4 31-5 31.6 31-7 31-9 — 33 31-2 31-4 31-4 31-5 31.6 31.8 31-9 32-0 32-1 32.3 32.4 32. S 32.6 32^7 32-9 — 34 32.2 32-3 32-3 34-4 32-5 32-7 32.9 33-0 33-1 33-2 33-3 33-5 33-6 33-7 33-9 — 35 iS-"^ 33-1 33-2 33-4 33-5 33-6 33-8 33-9 34-0 34-2 34-3 34-5 34-6 34-7 34-9 ~ 61 62 63 64 6s 66 67 68 69 70 71 7» 73 74 75 20 20.1 20.2 20.2 20.3 20.4 20.5 20.6 20.7 20.9 21.0 21. 1 21.2 21.3 21-5 21.6 21 21. 1 21.2 21-3 21.4 21-5 21.6 21.7 21.8 22.0 22.1 22.2 22.3 22.4 22.5 22.6 22 22.1 22.2 22,3 22.4 22.5 22.6 22.7 22.8 23.0 23-1 23-2 23.3 23-4 23-5 23-7 23 23-1 23.2 23-3 23-4 23-5 23.6 23-7 23-8 24.0 24.1 24.2 24-3 24.4 24.6 24.7 24 24.1 24.2 24-3 24-4 24-5 24.6 24-7 24-9 25.0 25-1 25.2 25-3 25 -5 25.6 25-7 *5 25-1 25.2 25-3 25-4 25-5 25-6 25-7 25-9 26.0 26.1 26.2 26.4 26.5 26.6 26.8 26 26.1 26.2 26.3 26.5 26.6 26.7 26.8 27.0 27.1 27.2 27-3 27-4 27-5 27-7 27. S *7 27.1 27-3 27-4 27-5 27.6 27-7 27.8 28.0 28.1 28.2 28.3 28.4 28.6 28.7 28.9 28 28.1 28.3 28.4 28.5 28.6 28.7 28.8 29.0 29.1 29.2 29.4 29-5 29.7 29.8 29-9 29 29.1 29-3 29.4 29-5 29.6 29:8 29.9 30-1 30.2 3°-3 30-4 30-S 30-7 30-9 31-0 30 30-1 30-3 30-4 30-S 30-7 30.8 30-9 31-1 31-2 31-3 31-5 31.6 31.8 31-9 32-1 31 31-2 31-3 31-4 31-5 31-7 31-7 31.8 32.0 32-2 32.4 32-5 32.6 32.8 33-° 33-^ 32 32-2 32-3 32.-5 32-6 32-7 32.9 33-° 33-2 33-3 33-4 33-6 33-7 33-9 34-0 34-2 33 33-2 33-3 33-5 33-6 33-8 33-9 34-0 34-2 34-3 34-5 34.6 34-7 34.9 35-1 35-2 34 34.2 34-3 34-5 34-6 34-8 34-9 3S-0 35-2 35-3 35-5 35.6 35-8 36 36.1 36.3 35 35-2 35-3 35-5 35-6 35.8 35-9 36-1 36.2 36.4 36.S 36.7 36.8 37.0 37-2 37.3 211 212 APPENDIX LEACH'S TABLE FOR CALCULATING TOTAL SOLIDS IN MILK BY BABCOCK'S FORMULA FROM QUEVENNE LACTOMETER READ- ING AND FAT. Per Cent of Fat. Lactoqjeter Reading at 15.3° C. 32 23 24 35 26 27 28 29 30 3t 32 33 34 35 36 o.o 5.50 5-75 6.00 6:2s 6. SO 6.75 7.00 7-25 7.50 7-75 8.00 8.25 8-So 8.75 9.00 O. I S.62 5.87 6.12 6.37 6.62 6.87 7.12 7-37 7.62 7-87 8.12 8.37 8.62 8.87 9.1 r o.a 5-74 5-90 6.24 6.49 6.74 6.99 7-24 7-49 7-74 7-90 8.24 8.40 8.74 8.99 9.24 0.3 5.86 6. II 6.36 6.61 6.86 7. II 7-36 7.61 7.86 8.11 8.36 8.61 8.86 9. II 9.36 0.4 SQ8 6.23 6.48 6.7.^ 6.98 7.23 7.48 7.73 7-98 8.23 8. 48 8.73 8.90 9.23 9.48 o.s 6.10 6.35 6.60 6.8s 7.10 7.35 7.60 7.8s 8.10 8.35 8.60 8.85 9.10 9-35 9.60 0.6 6.32 6.47 6.72 6.97 7.22 7.47 7.72 7-97 8.22 8.47 8.72 8.97 9.22 9-47 9.72 0.7 6.34 6.59 6.84 7.09 7.34 7*-S0 7-84 8.00 8.34 8.50 8.84 9.00 9-34 9-59 9.84 0.8 6.46 6.71 6.96 7.21 7.46 7.71 7-96 8.21 8.46 8.71 8.96 9.21 9.46 9.71 9.96 0,9 6.58 6.83 r.o8 7.33 7.58 7.83 8.08 8-33 8.58 8.83 9.08 '9-33 9-58 9.83 10.08 I.O 6.70 6.05 7.20 7-45 7.70 7.95 8.20 8 45 8.70 8.95 9. 20 9-45 9.70 9.95 to. 20 I.I 6.82 7-07 7.*2 7-57 .7.82 8.07 8.32 8-57 8.82 9.07 .9.32 9-57 9.82 10.07 10.32 1.3 6.04 7.10 7.44 7.60 7 -94 8.06 8.10 8.44 8.60 8.04 9.19 9.44 9.60 9.94 10.19 10.44 10. SO 1.3 7.06 7.31 7.56 7.8. 8.3. 8.56 8.81 9. 06 9-31 9-S6 9.81 10.06 10.31 1-4 7.18 7.4J 7.68 7.03 8.18 8.43 8.68 8.03 9.18 9-43 9.68 9.93 10.18 10.43 10.68 I-S 7 -30 7-55 7.80 8.0s 8.30 8.55 8. So 9.05 9 30 9-55 9.80 10.05 10.30 10.55 10.80 1.6 7.42 7.67 7.92 8.17 8.42 8.67 8.92 9.17 9-42 9.67 9.82 10.17 10.42 10.67 10.93 1.7 7-54 7-70 8.04 8.20 8.54 8.79 9.04 9.20 9-54 9-70 10.04 10. 20 10.54 ro.79 II .04 1.8 7.66 7-91 8.16 8.41 8.66 8.91 9.16 9,-41 9.66 ,9-91 1 . 1 (, 10.41 1(3.66 10.91 11.17 1.9 7.78 8.03 8.28 8.5.^ 8.78 9.03 9.68 .9-53 9.78 10.03 10.28 10.55 10.78 11.04 II . 29 3.0 7.90 8,15 8.40 8.65 8.90 9-15 9.40 9.65 9.03 9.38 9.63 9. 83 10.13 10.38 10.63 10.88 11.14 11-39 1 1 .64 11-89 a-S 8.50 8.75 9.00 9-25 9.50 9.75 10.00 10.25 10.50 10.75 1 1 .00 11. 26 11-51 11.76 12.01 3.6 8.60 8.87 9.12 9.37 9.62 9.87 10.12 10.37 10.62 10.87 II .12 11.38 11-63 11.88 12. 13 3.7 8.74 8.09 9.24 9-40 9.74 9.90 10.24 10.49 10.74 10.90 II .24 1 1. -SO 11.75 12.00 12 35 3.8 8.86 9. II 9.36 9.61 9.86 10.11 10.36 10.6! 10.86 1 1 . 1 1 ".37 11.62 fi.87 12.12 12.37 3.9 8.98 9-23 9.48 9.73 9.98 10.23 10.48 10.73 10. oS 11.23 11.49 11.74 1 1 .99 12.24 12.49 30 9.10 9.35 9.60 9.85 10. 10 10.35 10.60 10.85 11.10 11.36 11. 61 11.86 12.11 12.36 12.61 31 9.22 9-47 9.72 9.97 lo. 22 10.47 10.72 10.97 11.23 11.48 11.73 11.98 12.23 12.48 12.74 3-3 9.34 9-50 9.84 10.09 10.34 10. SO 10.84 11.09 11.35 II .60 11.85 12.10 12 35 12.61 12.86 3-3 9.46 9.71 9.96 10. 21 10.46 10.71 10.96 11.22 11.47 11.72 11.97 12. 22 12.48 12.73 12.85 12.98 3-4 9.58 9.8j 10.08 10.33 10.58 .0.83 II .09 11.34 11.59 11.84 12.09 12.34 12.60 13.10 3-S 9.70 9-05 10. 20 10.45 10.70 10.95 11.21 1 1 .46 II. 71 11 .96 12.21 12.46 12.72 12.97 13-23 3-6 9.82 10.07 10.32 10.57 10.82 11.08 11-33 11.58 11.83 12.08 12.33 12. sS 12.84 13.09 13-34 3-7 9-94 10. 29 10.44 10.79 10.94 1 1 . 20 II-4S 11.70 11-05 12. 20 12.45 12.70 12.96 13.21 13-46 3-8 10.06 10.31 10.56 10.81 11.06 ii.3> 11-57 11.82 12.07 12.32 12.57 12.82 13.08 13-33 13-58 3-9 10.18 10.43 10.68 10.93 II. 18 11.44 11.69 11.94 12.19 13.44 12.69 12.94 13-- 20 13-45 13.70 4.0 10.30 10.55 10.80 11.05 11.30 11.56 11-81 12.06 12.31 12.56 12. 81 13.06 13-32 13-57 13-83 4-1 10.42 10.67 10.92 11.17 11.42 11.68 ir.93 12.18 12.43 12.68 12.93 13-18 13-44 13.69 13-95 4.2 10. 54 10.70 II .04 1 1 . 29 11 .54 11.80 12.05 12.30 12.55 12.80 13.05 13-31 13-56 13-82 14-07 4-3 10.60 10.01 1 1. 16 11.41 11 .66 11 .92 12.17 12.42 12.67 12.92 13.18 13-43 13-68 13-64 14-19 4-4 10.78 11.03 11. 28 11.53 1 1 .78 12.04 12.29 12.54 12.79 13.04 13.30 13-55 13-80 14.06 14.31 4-S 10.90 11.15 11.40 n .6s 11.90 12.16 12.41 12.66 12.91 13.16 13.42 13.67 13-92 14.18 14-43 4.6 1 1 .02 11.27 11.52 11.78 12.03 12.28 12.53 12.78 13.03 13.28 13.54 13.79 14.04 14-30 14-55 4-7 II. 14 11.40 II. 6s 11. 90 12.15 1 2.40 12.6s 12.90 IJ.IS 13-40 13.66 13.91 14.16 14.42 14.67 4.8 11.27 11.52 11.77 I2.02 12.27 12.52 12.77 13-02 13.27 13.52 13.78 14-03 14.28 14-54 14.79 4.9 11.39 11.64 11.89 12.14 12.39 12.64 12.89 13.14 13-39 13-64 13.90 14. IS 14-40 14.66 14-91 S-O II .51 11.76 12.01 12.26 12. SI 12.76 13.01 13.26 13-51 13-76 14-02 14.27 1452 14.78 1S.03 S-> II .63 11.88 12.13 12.38 12.63 12.88 13-13 13.38 13-63 13-89 14.14 14.39 14.64 14.90 15. »S S-2 II .7'; 12.00 12.25 12.50 12.75 13.00 13-25 13-50 13-75 14.01 14.26 14-51 14.76 15.02 15.37 S-3 11.87 12.12 12.37 12.62 12.87 13.12 13-37 13-62 13-87 14.13 14.38 14.63 14.88 15.14 15.39 5-4 II 99 12.24 12.40 12.74 12.99 13.24 13-40 13-71 14-00 14-25 14.50 14.76 IS. 01 IS. 26 15. SI S-5 12. II 13.36 12.61 12.86 13. II 13.36 13-61 13.86 14.12 14-37 14.62 14.88 IS. 13 15.38 IS. 63 5-6 12.23 12.48 13.73 12.98 13.23 13.48 13-73 13.99 14.24 14-40 14.75 IS. 00 IS. 35 15.30 IS.7S S-7 12.35 12.60 12.85 13.10 13.35 13-60 13-85 14.11 14.36 14-61 14.87 IS. 12 IS. 37 IS. 62 15.87 5.8 12.47 13.72 13.07 13-22 13.47 13-72 1307 14.22 14.48 14.74 14.99 IS.24 IS.49 IS. 74 15-99 5-9 I2.S9 13.84 13.09 13.34 13-59 13-84 14-10 14-35 14.60 14.86 IS. II 13.36 IS.6i 15.86 16. IZ 6.0 13.71 13.96 13.31 13.46 13.71 13.96 14.32 14.47 i4-7i 14.98 iS-23 IS. 48 15-73 IS. 98 16.34 TABLES 213 MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE (Weights in Milligrams) i Invert Sugar and Sucrose. Lactose. Malt ose. s CJ, S 0. t a i i a 3 ft rt c5 i s w + 1 a + a X a a + a X a i Q 6 " CJ 10 8.9 4.0 A-S i>6 3j8 3.5 4.0 !•' 6.3 10 II 9.8 45 5.0 3.1 4is .4.6 4.7 6.7 7.0 It la 10.7 4.9 54 95 S.I 53 5-4 7.5 7.9 13 13 II .s 5-3 5.8 J.O S.8 1? 6.1 8.3 8.7 13 K I3.4 57 6.3 3 4 6.4 6.6 6.8 9.1 9.5 14 IS 1 3. "3 6.3 6.7 3.9 4.3 7.1 7.3 7.5 -9.9 10.4 «5 i6 14.3 6.6 7.3 7.8 8.0 8.2 10. 6 II. 3 16 17 IS-I 7.0 7.6 4.8 8.4 8.6 8.9 11.4 13.0 17 i8 16.0 7-5 8.1 5-3 9.1 9.3 9-5 13.3 13.9 t8 19 16.9 7-9 8.S 5-7 9.7 10. 10.3 13.0 13.7 19 30 17.8 8.3 8.9 6.1 10.4 10.7 10.9 13.8 14.6 30 31 18.7 8.7 9.4 6.6 II. II. 3 II. 6 14.6 IS 4 21 33 195 9.3 9.8 7-0 11.7 12.0 12.3 15.4 16.3 33 *3 30.4 9.6 10.3 7.5 12.3 12.7 13.0 16.3 17. 1 »J 94 31.3 10. 10.7 7.9 13.0 13.4 i3.7 17.0 17.9 24 as 33.3 10, S It .3 8.4 13.7 14.0 14.4 17.8 18.7 '! 36 33.1 10. 9' II. 6 8.8 14.3 14.7 IS. I 18.6 19.6 36 37 34.0 11-3 12.0 9.3 15.0 IS. 4 IS. 8 19.4 30.4 'I 38 34.9 tl.8 13. S 9.7 IS. 6 16. 1 16. S 20.3 31.2 28 39 35. 8 13.3 13.9 10.3 16.3 16.7 17. 1 31. 32.1 39 30 36.6 12.6 13.4 10.7 4.3 16.9 17.4 17.8 31.8 22.9 30 31 37. S 13. I 13.8 II. I 4.7 17.6 18. 1 18. S 33.6 23.7 3X 3' 38.4 13. S 14.3 11.6 s? 13.3 18.7 19.3 33.3 24.6 3» 33 393 13-9 14.7 13. S.6 18.9 19.4 19.9 34.1 »S.4 33 34 30.3 14.3 IS. 3 13. S 6.1 19.6 20.1 20.6 34.9 36.3 34 35 31. 1 14.8 IS. 6 13.9 6.S 20.2 30.8 21.3 3S.7 27.1 ^1 36 33.0 IS. 3 16. » 13-4 7.0 20.9 21.4 22.0 26. s 37.9 36 37 33.9 IS. 6 16. s 13.8 7.4 21. S 22.1 22.7 27. 3 38,7 n 38 33.8 16. 1 16.9 14.3 7.9 22.2 22.8 23.4 38.1 39.6 39 34.6 16. s 17-4 14.7 8.4 22.8 23. S 24.x 38.9 30.4 39 40 355 16.9 17.8 IS.i 8.8 23. S 34.1 24.8 39.7 31.3 40 41 364 17.4 18.3 IS. 6 9.3 24.2 34.8 2S.4 «o.s 33.1 41 43 37.3 17.8 18.7 16. t 9.7 24.8 ss.s 20.2 26.1 31.3 '*-2 4* 43 38.3 18.3 19.3 16.6 10.3 2S.S 26.8 32.1 33.8 4) 44 39.1 18.7 ig.o 17. 10. 7 36.1 36.8 27. S 33.9 34.6 44 45 40.0 19. 1 30.1 17. 5 II. t 26.8 27. S 28.2 33.7 35. 4 *l 46 40.9 19.6 20. s 17.9 II. 6 27.4 28.2 28.9 34.4 36.3 46 47 41-7 30. 21 .0 18.4 13 .0 28.1 28.9 29.6 35-3 37.1 *l 48 43.6. 30.4 31.4 18.8 I3.S 28.7 39. s 30.3 ^!S 32S 48 49 43 S 30.9 31.9 19.3 13.9 29.4 30,2 31.0 36.8 38.8 49 SO 44-4 31.3 33.3 19.7 13. 4 30.1 30.9 31.7 37.6 39.6 50 SI 453 31.7 33.8 30.3 13.9 30.7 31. s 32.4 38.4 40.4 51 51 46.3 32.3 33.3 30.7 14.3 31.4 32.2 33.0 39.3 41.3 5* 53 47.1 33.6 33.7 31. I 14.8 3i.i 32.9 33.7 40.0 43.1 53 54 48.0 33.0 34-t 31.6 IS. 3 32.7 33.6 34.4 40.8 43.9 54 SS 48.9 33.5 34.6 33.0 IS. 7 33.4 34.3 35.1 41.6 43.8 S| S6 49-7 339 35.0 22. S 16.2 34-0 34.9 3S.8 43.4 44.6 56 57 50.6 34.3 35.5 22.9 16.6 34-7 3S.6 36. S 43. a 45-4 11 S8 Si-S 34.8 359 23-4 17.1 35.4 36.3 37.2 44 46.3 S9 S3. 4 3S.3 36.4- 33.9 «7.S 36,0 37.0 37.9 44.8 47.x 59 6o S3. 3 3S.6 36.8 34. 3 18.0 36.7 37.6 38.6 4S.6 48.0 60 6i 54.3 36.1 37.3 34.8 18. S 37.3 38.3 39.3 46.3 48.8 61 63 SSI 36. s 37.7 2S.3 18.9 38.0 39 40.0 47.1 49-6 63 63 S6.6 370 38.3 35.7 19.4 33.6 39.7 40.7 47.9 50. S 63 64 .56.8 a7.4 38.6 36,1 19.8 ».3 40.3 41.4 48.7 51.3 64 214 APPENDIX MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— (Coniimied) (Weights in Milligrams) q Invert Sugar and Sucrose. Lactose. Maltose. d 3 3 c^ L) t) "rt „ Q d 4) 1 1 1 ^ 1 > 2 s, 2 6S, + 6 + s 3 + 6 •0 3 3 1 i 0^ 2^ c5w n X £3 a a S a 3 O Q d " 6 6$ 57-7 27.8 29.1 26.6 20.3 40.0 41.0 42.x 49-5 52.1 6s 66 58.6 28.3 29-5 27.1 20.8 40.6 41.7 42.8 SO. 3 53 66 67 S9S 28.7 30.0 27-5 21.2 41.3 42.4 43. s SI. I 53.8 67 68 60.4 29.2 30.4 28.0 21.7 41.9 43.1 '44.2 . 51.9 54.6 68 69 61.3 29.6 30.9 28. S 22.2 42.6 43.7 .44-8 52.7 55. 5 69 70 62.1 30.0 31.3 28.9 22,6 43-3 44.4 45. S 53-5 56.3 70 7« 63.1 30. 5 31.8 29.4 23.1 43.9 45.1 46.2 54.3 57-1 71 7* 64.0 30.9 32.3 29.8 23. s 44.6 45.8 46.9 55-1 58.0 72 73 64. S 31-4 32.7 30.3 24.0 45.2 46.4 47.6 SS-9 58.8 73 74 65.7 31.8 33-2 36.8 24.5 45-9 47.1 48.3 56.7 59.6 74 7S 66.6 32.2 33.6 31.2 24.9 46.6 47.8 49.0 57. S 60.5 75 76 67.5 32.7 34.1 31.7 25.4 47.2 48. 5 49.7 S8.2 61.3 76 'Z 68.4 33 1 34-5 32.1 2S.9 47.9 49.1 50.4 590 62.1 77 78 69 -3 33.6 3SO 32.6 26.3 48.5 49.8 51. 1 1'! 63.0 78 79 70.2 34-0 35-4 33-1 26.8 49.2 SO. 5 SI. 8 60.6 63.8 79 8o 71. 1 34-4 35-9 33-5 27-3 49-9 SI. 2 52. S 61 .4 64.6 80 8t 71.9 34-9 36.3 34.0 27.7 50.5 51.9 53.2 62.2 6s.S 81 82 72.8 35-3 36.8 345 28.2 51.2 52. 5 53.9 63.0 66.3 82 83 73-7 35-8 37-3 34-9 28.6 51.8 53-2 54.6 63.8 67.1 83 84 74.6 36.2 37.7 35-4 29. 1 52-5 53-9 55-3 64-6 68.0 84 8S 75 -S. 36.7 38.2 35.8 29.6 53- 1 54.6 56.0 65.4 68.8 8S 86 76.4 37.1 38.6 36.3 30.0 53.8 55-2 56.6 66.2 69 -7 86 87 77-3 37-5 391 36.8 30. S 545 55.9 57. 3 67 .0 70.5 87 88 78.2 38.0 39-5 37.2 31.0 55.1 S6.6 58.0 67.8 71.3 88 89 79.1 38.4 40.0 37.7 31.4 55.8 57.3 S8.7 68.5 72.2 89 90 79-9 38.9 40,4 38.2 31.9 S6.4 58.0 59.4 69 -3 73.0 90 9' 80.8 39-3 40.9 38.6 32.4 57. 1 58.6 60.1 70.1 73.8 91 92 81.7 39.8 41-4 391 32.8 57.8 59-3 60.8 70.9 74. V 92 93 82.6 40.2 41.8 39-6 33.3 58.4 60.-0 61.5 71-7 75. S 93 94 83.5 40.6 42.3 40.0 33.8 59. 1 60.7 62.2 72. S 76.3 94 95 84.4 41. 1 42.7 40. 5 34.2 59.7 61:3 62.9 .73.3 77.2 9| 96 85.3 41-5 43-2 41.0 34.7 60.4 62.0 63.6 74.1 78.0 96 97 86.2 42.0 43.7 41.4 35-2 61. 1 62.7 64.3 74.9 78.8 97 98 87.1 42.4 44 I 41.9 3S-6 61.7 63.4 65.0 75.7 79.7 98 99 87.9 42.9 44 .-6 42.3 36.1 62.4 64.0 65.7 76. 5 80. S 99 Too ' .88.8 43-3 45.0 42.8 36.6 63.0 64.7 66.4 77.3 81.3 ibo lOI 89.7 43-8 45-5 43.3 37.0 63.7 65.4 67.1 78.1 82.1 lOI lOJ 90.6 44.2 46.0 43-8 37. 5 64.4 66.1 67.8 78.8 83.0 loa 103 91S 44.7 46.4 44.2 38.0 65.0 66.7 68.5 79.6 83.8 103 104 92.4 45.1 46.9 44.7 38.5 65.7 67.4 69. 1 80.4 84.7 104 los ,93 -3 45-5 47-3 45. > 38.9 66.4 68.1 69.8 81.2 85. s los 106 94.2 46.0 47-8 45.6 39.4 67.0 68.8 70. 5 82 .0 86.3 106 107 95 46.4 48.3 46.1 39-9 67.7 69 S 71.2 82 .8 87.2 107 108 95-9 46.9 48.7 46.6 40.3 68.3 70.1 71.9 83.6 88.0 108 109 96.8 47-3 49-2 47.0 40.8 69.0. 70.8 72.6 84.4 88.8 100 JIO 97-7 47.8 49-6 47-5 41-3 69.7 71. 5 73.3 85.2 89.7 no III 98.6 48.12- 50.1 48.0 41.7 70.3 72.2 74.0 86.0 86.8 87.6 88.4 90. 5 III 112 99-5 48.7 50.6 48.4 42.2 71.0 72.8 74.7 91.3 112 113 100.4 49- 1 51.0^ 48.9 42.7 71.6 73.5 75.4 92 .2 113 114 loi .3 49-6 5I-S 49.4 43-2 73.3 74-2 76.1 930 114 "S 102.2 SO.O SI. 9 49-8 43.6 73-0 ■74.9 76.8 89.2 93.9 IIS 116 103.0 ' 50.5 52.4 50.3 44.1 73.6 75.6 77. S 90.0 94.7 116 117 103.9 SO -9 52.9 SO. 8 44.6 74.3 76.2 78.2 90.7 95. 5 117 118 104.8 51-4 53-3 51.2 45-0 7S.0 76.9 78.9 91-5 96.4 118 119 105.7 St. 8 53.8 51.7 45. S 75.6 77.6 79.6 93-3 97.2 119 TABLES 215 MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— {Conlinued) (Weights in Milligrams) o 3 Invert Sugar and Sucrose. Lactose. Maltose. 1 d 6 ■o u . 5 S X K w 1 •R "a 00 t- H + + + O 1 u ■0. a. £ a 3 W > h ,03 h i i 1 6 d a d " c u X30 X06.6 52-3 54.3 52-2 46.0 76.3 78.3 80.3 93-1 98.0 98.9 120 131 10-7.5 108.4 109-3 IXO. I 52 .7 54-7 52.7 46.5 76 - 9; 79-0 81.0 93.9 I2X 133 53-2 55.2 53-1 46.9 77.6 79-6 81.7 94-7 99.7 X22 123 "4 . S3 - 6 54-1 55.7 S6.i 53-6 54.1 47-4 47-9 78.3 ,78.9 80.3 61.0 82.4 83.1 9S-5 96.3 100. 5 101.4 123 124 126 III .0 54. S. 56.6 54. 5 48.3 79.6 81.7 83.* 97.1 ioa.2 12s 126 XIX .9 112. 8 55.0 57.0 55-0 48.8 80.3 82.4 84-S 97-9 loslo 127 128 55-4 57-5 55-5 49-3 80.9 830 85-2 98.7 103.9 127 128 II3-7 XI4-6 55-9 58.0 55-9 49-8 81.6 83-7 85-9 99-4 104-7 <39 56.3 58.4 56-4 50.2 82.2 84-4 86.6 XO0.3 105-5 T29 130 131 132 133 134 iiSS 116. 4 XI7-3 X18.X 56-8 57.2 58. f 58.9 59-4 59-8 60.3 56-9 57-4 57-8 58.3 SO. 7 51.2 51.7 52. X 82.9 83.6 84.2 84.9 85. 1 85.7 86.4 87-1 87-3 88.0 88.7 89-4 xoi .0 101.8 X02.6 103.4 106.4 107.2 108.0 108.9 130 I3< 132 133 119. S8.6 60.8 58.8 S2.6 85. S -87.8 90. 1 X04.3 X09.7 U4 I3S 136 138 139 XT9.9 59.0 61.2 59-3 S3. 1 86.2 88. S 90.8 XOJ.O xio.s I3S 136 120.8 59-5 61.7 59-7 53.6 86.9 89. 1 91. S X0S.8 III. 4 121. 7 X22 .6 60.0 62.2 60.2 54-0 87. S 89.8 92.1 106.6 112.2 X38 60.4 62.6 60.7 54. S 88.3 90. S 92.8 107.4 113 -0 123.5 60.9 63.x 61.2 SS-o 88.9 91.3 93. S X08.2 113.9 139 X40 124.4 61.3 63.6 61.6 55. S 89. S 91.9 94.2 109.0 109. 8 114.7 X40 141 X2S . 3 61.8 64.0 62.x 559 90.2 92. S fl4-9 115-5 116.4 141 142 X26.-I 62.2 64.5 62.6 S6-4 90.8 93.2 95-6 110.5 X42 X43 127.0 62.7 65.0 63.x SO -9 91-S 93 9 94-0 96.3 III. 3 X17-2 X18.0 143 144 X27.9 63.1 65.4 63. S 57.4 92.2 97.0 112. I 144 145 X28.8 63.6 65-9 64.0 57. 8 92.8 958 97-7 XX2.9 T18.9 145 X46 146 147 129. 7 64.0 66.4 64-S S8.3 93-5 959 98.4 113.7 119-7 130.6 64-5 66.9 65.0 58.8 94.2 96.6 99-1 114-S 120.5 147 148 148 i3f.S X33-4 65.0 67.3 65.4 59-3 94-8 97.3 99-8 115-3 121 .4 149 65.4 67.8 65-9 59-7 95. S 98.0 100. 5 X16. X X22 .2 149 150 133 -2 65.9 68.3 66.4 60.2 96.1 98.7 101.2 116. 9 123.0 ISO 151 IS2 153 '54 134- 1 66.3 68.7 66.9 60.7 96.8 99.3 I0I.9 X17-7 123-9 151 135 -O 66.8 69.2 67-3 61.2 97 -S 100. 102.6 ii9.S 124. 7 152 135.9 67.2 69.7 67.8 61.7 98.1 100.7 103.3 X19-3 12S-5 126.4 153 136.8 67.7 70.1 68.3 62.x 98.8 ipi.4 104.0 X20.0 154 15s 156 157 158 137 . 7 68.2 70^6 68.8 62.6 99- S 102. 1 104.7 120.8 127.2 128.0 128.9 129-r is's 156 138.6 68.6 71. 1 69.2 63-1 100. 1 102.8 10S.4 121 .6 1395 140.3 69.1 69. s 71.6 72.0 69-7 70.2 63-6 64-1 100.8 lOI.S 103.4 104. 1 106. 1 106.8 122.4 X23.a 157 158 159 141. 2 70.0 72. S 70.7 64. S 102. I 104.8 107. S X24.0 130. 5 159 160 161 142. X 143 .0 70.4 70.9 73.0 73-4 71.6 65.0 65-5 102.8 103-4 105. S 106.2 108.2 108.9 124.8 H5-6 131-4 132.2 160 161 i6» 163 164 162 163 164 143-9 144.8 X4S-7 71-4 71.8 n-3 73-9 74-4 74-9 72.1 72.6 73 -X 66.0 66.5 66.9 104. t 104.8 IOS.4 106.8 107. 5 108.2 109.6 no. 3 Ilt.O 126. 4 X27.» 128.0 133 133 9 134-7 j6s 166 J46.6 147 . 5 72.8 73 • 2 75-3 75-8 73-6 74.0 67-4 67.9 106. T 106.8 108.9 i09.6 III. 7 112.4 128.8 129.6 135 5 136.4 x6s 166 167 x68 169 167 148.3 73-7 76-3 74-5 68.4 107.4 110.3 1131 113. 8 114-S 130.3 1J7- 2 168 169 149.2 150.1 74-6 76.8 77-2 75-0 75-5 68.9 69-3 108.. 108.8 110.9 III. 6 131-1 13IJ9 13..- 138.9 X70 ISI -o 75- 1 77.7 76.0 69.8 109.4 112. 3 11S.2 132-7 139-7 170 171 172 xsi .9 75-5 78.2 76.4 70.3 110. I 113. 115-9 133-S 140- S X71 152 .8 76.0 78.7 76.9 70.8 no. 8 113-7 116. 6 134-3 141-4 I7» 173 174 153.7 154-6 76.4 76.9 79-1 79-6 77-4 77-9 71-3 71-7 III. 4 113. I 114-3 115. 117. 3 118. 135-1 1359 142.2 143.0 »7J 174 216 APPENDIX MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— {Contiftiied) (Weights in Milligrams) o Invert Sugar and Sucrcse. Lactose. Malt ose. 3 3 <^ i •a o 3 3' 3 d ■5 a + 6 <2 + 6 d d + d 4) a p 1 u ■s a u> it n u n n o 1 C 3 (5w K s d W S K 0. z) I7S ISS-S 77-4 80.1 78.4 72.2 112. 8 IIS. 7 118.7 136.7 143-9 17^ 176 156.3 77-8 S(X>6 78-8 72.7 113. 4 116.4 119. 4 137.5 144-7 176 177 157-3 78.3 81.0 79-3 73-a 114. 1 117. 1 120.1 138.3 145-5 177 178 158. 1 78.8 81.5 79-8 73-7 114. 8 117. 8 120.8 139. 1 146.4 17S 179 159.0 79.3 83.0 80.3 74-3 IIS. 4 118.4 121. s 139-8 147.2 179 180 159. 9 79-7 83.5 80.8 74.6 116. 1 119. 1 122.2 140.6 148.0 180 181 160.8 80. 1 82.9 81.3 75-1 116.7 119.8- 122.9 141. 4 148.9 181 182 161 .7 80.6 83.4 81.7 75-6 II7-4 120.5 123.6 142.3 149-7 182 183 162.6 81. 1 83 -9 82.3 76.1 118. 1 121 . 2 124.3 "143.0 I SO -5 183 184 163.4 81.5 84.4 83.7 76.6 118.7 121. 8 125.0 143.8 151-4 184 l8s 164.3 83.0 84.9 83.3 77.1 H9-4 122. s 125.7 144.6 152-2 185 186 165.3 83.5 85-3 83-7 77.6 120. 1 123.2 126.4 145.4 153-0 186 187 166. 1 83.9 85.8 84.2 78.0 120.7 123.9 127.1 146. 3 1S3-9 187 1 83 167.0 83.4 86.3 84.6 78.5 121. 4 124.6 127.8 147-0 154-7 188 189 167.9 83.9 86.8 8s. 1 79.0 122. 1 12s. 3 128 S 147-8 iSS-S 189 190 168.8 84.3 87.3 85-6 79. S 122.7 125.9 129.2 148.6 156.4 190 191 169.7 84.8 87.7 86.1 80.0 123.4 126.6 129.9 149-3 1S7.2 191 193 170.5 85-3 88.2 86.6 80. 5 124. 1 127.3 130.6 ISO- 1 158-0 19? 193 l1l-4 85-7 88.7 87.1 81.0 124-7 128.0 131.3 150.9 158.9 19., 194 173.3 86.3 89.3 87.6 81.4. 125-4 128.7 132.0 151-7 159.7 194 19$ »73.a 86.7 89.6 88.0 81.9 126. 1 129.4 132.7 152-5 160. 5 I9S 196 174. 1 87.1 90. 1 88.5 82.4 126.7 130.0 133.4 IS3-3 161 .4 196 197 175.0 87-6 90.6 89-0 83.9 127.4 130.7 134.1 IS4-I 162 .2 197 198 J7S.9 88.1 91-1 89-5 83.4 128. 1 131. 4 134.8 154-9 l6j.o 198 199 176.8 88.5 91 .6 90.0 83.9 128.7 132. 1 • 135. S lSS-7 163.9 199 300 177.7 89.0 92.0 90.5 84.4 129.4 132.8 136.2 156.5 164.7 300 aoi 178.5 89-S 92. S 91 .0 84.8 130.0 133. S 136.9 157.3 165.5 30I 303 179-4 89.9 930 91-4 85. 3 130.7 134.1 137.6 158. 1 166.4 3oa 303 180.3 90.4 J>3-5 91.9 85.8 131.4 134.8 138.3 158.8 167.3 303 304 181. 3 90.9 94.0 93.4 86.3 132.0 I3S.S 139.0 159-6 168.0 304 305 18]. I 91.4 94. S 93.9 86.8 132.7 136. 2 139.7 160.4 168.9 305 ao6 183.0 91.8 94.9 93-4 87.3 133-4 136.9 140.4 161 . 3 169-7 300 307 183.9 93-3 95-4 93-9 87.8 134-0 137.6 141. 1 162.0 170.5 307 308 184.8 93-8 95-9 94-4 88.3 134-7 138.3 141.8 162.8 171.4 208 309 185.6 93 -a 96.4 94.9 88.8 135-4 138.9 142. S 163.6 173.3 209 aio 186. 5 93-7 96.9 9$. 4 89-3 136 ."0 139.6 143.2 164.4 173 210 311 187.4 94 3 97.4 95-8 89.7 136.7 140.3 143.9 165.3 173.8 2H 313 188.3 94-6 97-8 96.3 90.3 137-4 141.0 144.6 166.0 174.7 313 313 f89.2 95-1 98-3 96.8 90.7 138.0 141.7 14s. 3 166.8 175-5 213 314 J90. 1 95-6 98.8 97-3 91.3 138.7 142.4 146.0 167.5 176.4 314 ais 191 .0 96.1 99>i 97.8 91-7 13* .4 143.0 146.7 168.3 177.3 3I| 316 191 9 96.5 99.8 98.3 93.3 140.0 .143.7 147.4 169. 1 178.0 3l6 317 193.8 97.0 100 .3 98.8 93.7 140.7 144.4 148.1 169.9 178.9 317 3l8 193-6 97-5 100.8 99-3 93. a 141.4 145.1 148.8 170-7 179.7 2l3 319 194 -S 98.0 loi .3 99 8 93.7 143.0 143-8 149. S 171. 5 180.5 319 330 I9S-4 98.4 101.7 100-3 94.* 142.7 146- S 150.2 173.3 181.4 320 331 196.3 98.9 103.3 100.8 94.7 143.4 147-2 150.9 173.1 182.3 331 333 197-3 99-4 I03 .7 lOI .3 95.1 144.0 147-8 151.6 173-9 183.0 333 333 198. I 99-9 103.3 101.7 95-6 144.- 7 148. S isa.3 174-7 183.9 333 334 199-0 100.3 103-7 103.3 96. 1 14s -4 149.2 153.0 175-5 184.7 334 335 199 9 100.8 104.3 103.7 96.6 146.0 149.9 153.7 176.3 *!l-5 335 336 300.7 iqi-3 104.6 103.3 97.1 146-7 150.6 154-4 177.0 186.4 326 337 30I .6 101.8 105. 1 103.7 97.6 147.4 ISI.3 155-1 177.8 187.3 227 338 303. 5 103 .3 105.6 104.3 98. 1 148.0 152.0 155.8 178.6 188.0 228 339 303.4 103.7 106. 1 104.7 98.6 148.7 152.6 156-S 179.4 188.8 339 TABLES 217 MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— {Conlinued) (Weights in Milligrams) i Invert Sugar and Sucrose Lactose. Maltose. i o. _ d d d u e i BO 5 •3 1 X •*> (2 •4 X ■R 9 H + + + o 0, 0. 8 g 3 1 is 11 a X 1 9 3 3 53 a a 3 9 cS Q c 6 « 6 230 204 -3 103.3 106.6 105.3 99:1 149-4 153.3 157-2 180.2 189.7 230 231 205 .2 10^.7 107 - ' 105.7 99-6 150.0 1540 1579 181 .0 1 90.- 5 231 232 206.x 207 .0 104- 1 107 .6 106.2 100. 1 150.7 154-7 158.6 181. 8 191-3 232 233 234 J04.6 108. 1 106.7 100.6 151.4 155-4 159.3 183.6 193.3 233 207.9 105. 1 108-6 107.3 101 . 1 152.0 156. 1 160.0 183.4 193-0 334 23s 236 237 238 239 208.7 105.6 109. 1 107.7 rot. a 152.7 156.7 160.7 184.2 193-8 "1 309.6 106.0 109.5 108.2 103. 1 153. 4 157.4 161. 4 184.9 194-7 236 210. 5 106. 5 IIO.O 108.7 102 .6 154-0 158. 1 162.1 185.7 195-5 237 211 .4 107.0 110.5 109.2 103.1 154-7 158.8 162.8 186.5 196.3 238 312.3 107-5 III.O 109.6 103.5 155-4 159. S 163. S 187.3 197.2 239 240 241 213.2 2M.I 108.0 111. 5 IlO.l 104.0 156. 1 j6o;2 164.3 188.1 198.0 240 108.4 113. 110.6 104. 5 156.7 160:9 165.0 188.9 198.8 241 242 243 215.0 215.8 108.9 113.5 III .1 105.0 157.4 161.S. 16S-7 189-7 199-7 242 109.4 113-0 iir.6 105. i 158.1 162.2 166.4 190.5 200.5 243 244 216.7 109-9 113-S 112. 1 106.0 158.7 162.9 167. 1 191.3 201.3 244 245 246 247 217.6 no. 4 114.0 112. 6 106.5 159. 4 163.6 167.8 192. 1 202.2 24s 218.5 no. 8 114.5 1I3-I 107.0 160.1 164.3 168. S 192.9 203 .0 246 319.4 III .3 115.0 113-6 107.5 160.7 165.0 169.2 193-6 203.8 247 3 48 248 320.3 m -8 115-4 114-1 108.0 161.4 165.7 169.9 194-4 204.7 249 231.2 112. 3 liS-9 114.6 108. 5 162.1 166.3 170.6 195-2 205.5 ?49 250 2SI 253 253 3 3 2.1 112. 8 116. 4 itS-i 109.0 162.7 167.0 171-3 196.0 206.3 3 50 333.0 323-8 324. 7 113. 2 116.9 115-6 109.5 163.4 167.7 172.0 196.8 207.2 351 113-7 117.4 116. 1 IIO.O 164. 1 168.4 172.7 197-6 208.0 352 114-2 117.9 116.6 110.5 164.7 169.1 173. 4 198.4. 208.8 253 254 325.6 114-7 118.4 117.1 III .0 165.4 169.8 174-I 199.2 209.7 254 256 257 226. s 327.4 228.3 IIS-2 118. 9 117.6 iii.S 166. 1 170. s 174-8 300.0 210.5 '^1 115.7 119.4 118. 1 112 .0 166.8 171. 1 17S-S 300.8 211 ,3 356 116.1 119.9 118.6 112.5 167.4 171. 8 176.2 201.6 212. 2 258 259 329.3 116. 6 130.4 119. 1 113-0 168. 1 172. S 176.9 202.3 213,0 330. 1 117. 1 120.9 119.6 113. S 168.8 173-2 177-6 203.1 313.8 259 360 331 .0 it7.6 131. 4 120. t 114.0 169.4 173.9 178.3 203.9 314.7 260 36x 231 .8 118. 1 131. 9 120.6 114.5 170. 1 174-6 179.0 204.7 215-S 261 262 363 2^2 . 7 118. 6 133 .4 121. 1 115.0 170.8 175-3 179.8 205.5 216-3 361 233 .6 119. 122.9 121 .6 1155 171. 4 176.0 180.5 206.3 217-2 263 264 234-5 119. 5 123.4 122. 1 116.0 172. 1 176.6 181. 3 207.1 218.0 264 26s 266 235-4 336.3 130.0 123.9 123.6 116. S 172.8 177.3 181. 9 207.9 218.8 26s I30.5 124.4 123.1 117.0 173. S 178.0 182.6 208.7 219-7 266 367 368 369 367 337.3 121 .0 124.9 123.6 117-S 174-1 178.7 183.3 209. 5 330-5 368 238.1 131 .5 135.4 124.1 118.0 174.8 179.4 184.0 210.3 331.3 269 238.9 132. 125.9 124.6 118. S 175-S 180.1 184-7 211.0 222.1 270 239.8 122. S 126.4. 125.1 119.0 176. 1 180.8 185-4 211.8 233.0 37a 27L 372 273 274 240. 7 122.9 126.9 125.6 119-S 176.8 181. 5 186.1 212.6 233.8 27)1 341 .6 123.4 127.4 136.2 120.0 177. S 182. 1 186.8 213-4 224.6 37« 343.5 343-4 123-9 124.4 127.9 128.4 136.7 137.2 120.6 121.1 178.1 178.8 182.8 183.5 187. S 188.3 214.2 215.0 225-5 326.3 273 274 276 244-3 245.2 124-9 135.4 138.9 139.4. 127.7 128.2 121. 6 133. I 179. S 180.2 184-2 1849 188.9 189.6 215.8 216.6 227.1 228-0 238-8 339.6 »7S 276 277 278 246.1 246.9 135-9 136.4 139.9 130.4 138.7 139.2 133.6 123.1 180.8 181. S 18S.6 18^.3 190.3 19IJO 217-4 318.2 277 278 279 247.8 136.9 130.9 129.7 123.6 183.2 187.0 191-7 318.9 330. 5 2 7» 280 248.7 137.3 131-4 130.2 124. t 182.8 187.7 192.4 219.7 231.3 280 281 281 28J 284 38t 249.6 137.8 131 .9 130-7 124.6 183. s 188.3 193.1 220.5 232.. I 282 250^5 138.3 133 .4 131-2 125.1 .184.2 189.0 193.9 194.6 221.3 233.0 233.8 383 251 ,4 138.8 133.9 131.7 125.6 184.8 189.7 233.1 284 252.3 139.3 133-4 .133.2 126.1 I8s-S 190.4 195-3 332,9 234,6 218 APPENDIX MUNSON AND WALKER'S TABLE FOR C.\LCULATING SUGARS FROM CUPROUS OXIDE— (Continued) (Weights m Milligrams) q Invert Sugar and Sucrose. Lactose. Maltose. 1 3 (3 V 'ti _ d d •o O 3 c H- 1 0^ 6 u X 6 =5 X 1 s a 3 285 253-2 129.8 133.9 132.7 126.6 186.2 191. 1 196.0 223.7 235.5 285 J 86 254.0 130.3 1 344 133 2 127. 1 186 9 191. « 196 7 224.5 236.3 286 287 2549 130.8 134.9 133 7 127.6 187.5 192. s 197.4 225.3 237-1 287 288 255-8 131. 3 135.4 134-3 128. 1 188.2 193 2 198 I 226.1 238.0 288 389 256.7 131.8 135-9 134-8 128.6 1.88 9 193-8 198 8 226.9 238.8 289 290 257.6 132-3 136.4 135-3 129.2 189 S 194-5 199 5 227.6 239,6 290 291 258.5 132.7 136.9 135-8 129.7 190 2 195-2 20'0 2 228.4 240 5 291 292 2594 133.2 137.4 136-3 130.2 190.9 195-9 200 9 229 2 241 .3 292 293 260.3 133.7 137.9 136.8 130.7 191. 5 196.6 201 6 230 242. 1 293 294 261 .2 134-2 138.4 137-3 131.2 192 2 197.3 202 3 230.8 242.9 294 29s 262.0 134-7 138 9 137-8 131.7 192 9 198.0 203.0 231 6 243-8 29s 2?6 262 .9 135-2 139 4 138.3 132 2 193 6 198.7 203 7 232.4 244-6 296 297 263.8 135-7 140.0 138.8 1^2.7 194 i 199.3 204 4 233 2 245-4 297 298 264.7 136.2 140.5 139.4 133 2 194 9 200.0 20s I 234 246.3 298 299 26s. 6 136.7 141 .0 139-9 133.7 195 6 200. 7 20s 8 234 8 247. 1 299 300 266.5 137.2 141 .5 140.4 1^4.2 196 2 201.4 206.6 235.5 247-9 300 301 267.4 137.7 142 .0 140.9 134 8 196.9 202 . I 207 3 236.3 248.8 301 302 268.3 138.2 142.5 141. 4 135 3 197.6 202.8 208 237 1 249 6 302 303 269.1 138.7 143 141.9 135.8 198 3 203. S 208 7 ^37 9 250.4 303 304 270.0 139-2 143-s 142.4 136.3 198 9 204.2 209 4 238 7 251-3 304 305 270.9 139.7 144-0 142.9 136.8 199.6 204 9 210. I 239 5 252.1 30s 306 271.8 140. 2 144.5 143-4 137 3 200 3 20s 5 210 8 240.3 252 9 306 307 272.7 140.7 145.0 144 137.8 201 206. 2 211 S 241 I 253 8 307 308 273.6 141. 2 145-5 144-5 138.3 201 6 206.9 212. 2 241 9 254 6 308 309 274-5 141-7 146. 1 1450 138 8 202 3 207 6 212.9 242 7 255-4 309 310 275-4 142.2 146.6 145-5 139.4 203.0 208.3 213 7 243 5 256.3 310 311 276.3 142.7 147 I 146.0 139.9 203 6 209 214 4 244-2 257 I 311 3«2 .277-1 143-2 147.6 146. 5 140.4 204.3 209.7 215 1 245 257-9 312 3'3 278.0 143-7 148. 1 147-0 140.9 205 210.4 215 8 245-8 258 8 313 3>4 278.9 144-2 148 6 147 6 141.4 205 7 211 I 216. S 246 6 259 6 J14 31S 279.8 144.7 149 I 148. 1 141 .9 206.3 211. 8 217 2 247-4 260 4 31s 316 280.7 145 2 149 6 I48.6 142 .4 207 212. S 217 9 248.2 261, 2 316 317 281.6 145.7 150.1 149.1 143 207 7 213 I 218 6 249 262 I 317 318 282. s 146 2 150.7 149 6 143 5 308 4 213.8 219 3 249 8 262.9 318 319 283 4 146,7 151.2 150.1 144.0 209 214 S 220 250 6 263.7 319 350 284.2 147.2 151. 7 150.7 144.5 209.7 2IS.2 220.7 251 3 264 6 320 321 285 I 147.7 152 2 151.2 145.0 210 4 215.9 221.4 252 I 265 4 321 322 286 J48.2 152,7 151. 7 145.5 aii.o 2X6.6 222.2 252:9 266 2 322 323 285.9 148.7 153.2 152.2 146.0 211. 7 217-3 222 9 253 7 267 1 323 324 287 8 149-2 IS3-7 152 7 146.6 212.4 218 223 6 254-5 267 9 324 32s 288 7 149.7 154-3 153 2 147.1 213. 1 218.7 224 3 255 3 26?. 7 32s 326 289.6 150.2 154-8 153. « 147.6 213.7 219 4 225 256 I 269 6 326 3^1 290.5 150.7 155 3 154.3 148. I 214.4 220 I 225 7 256.9 270 4 327 328 291 4 151.2 155-8 154 8 148.6 21S.1 220. 7 226 4 257 7 271.-2 328 329 292.2 151-7 156.3 155-3 149. 1 31S.8 221.4 227 I 258.5 272.1 329 330 293 I 152.2 156.8 1^5 8 149.7 216 4 222. 1 227.8 259. 3 272.9 330 331 294.0 152.7 157.3 156.4 150. 2 217. 1 222 8 228 5 260 273.7 331 332 294.9 153.2 157-9 156.9 150.7 217.8 223 S 229 2 260 8 274.6 332 333 295.8 153.7 158 4 157-4 151.2 218.4 224. 2 230 261 6 275.4 333 334 296.7 154. 2 158 9 157.9 151.7 219. 1 224.9 230 7 262 4 276.2 334 335 297.6 154.7 159-4 158.4 152.3 219.8 225.6 231.4 263 2 277.0 33S 336 298. s 155.2 159-9 159.0 152.8 220.5 226.3 2 2.1 264.0 277.9 336 337 299.3 155 8 160. s 159. 5 1 53 . 3 221 I 227. 232 8 264.8 278 7 337 338 300. 2 156 3 161 .0 160 153. 8 221.8 227.7 233 S 265.6 279 5 338 339 301 I 156 8 161 .5 160. s 154.3 222. s 228.3 234.2 266.4 280.4 •339 TABLES 2ig MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— (Continued) (Weights est Milligrams) 342 343 344 34S 346 347 348 349 350 351 353 353 354 355 356 357 3S8 359 360 361 36a 363 364 36s 366 367 368 369 370 371 37a 373 374 375 375 377 378 379 380 381 38» 383 38s 386 387 388 389 390 391 39» 393 394 3oi.o 3039 303-8 304-7 305-6 306. 5 307-3 308.1 309.1 310.0 310.9 3II-8 312-7 313-6 314-4 315-3 316-2 317-I 318.0 318.9 319-8 320.7 321.6 322.4 3233 3242 325-1 326.0 326.9 327.8 328.7 3295 330.4 3313 332-2 333-1 3340 334-9 335-8 336.7 337-5 338.4 339-3 340.2 34I-I 342.0 342.9 343-8 344-6 345-5 346.4 347.3 348.2 349." 350.0 57-3 57-8 58.3 58.8 59-3 59.8 60.3 60.8 61 .4 61 .9 62.4 62 .9 63.-4 63 -9 64.4 64.9 65.4 66.0 66. S 67.0 67. 5 68.0 68. S 69.0 69.6 73-7 74.2 74.7 76.3 76.8 77-3 77-9 78.4 78.9 79-4 80.0 80. S 81..0 81. S 82.0 82.6 83.1 83.6 84.1 84.7 85.2 Invert Sugar and Sucrose. Lactose. 6j .0 62.5 63.1 63.6 64-. t- 64.6 65.1 65-7 66.2 66.7 67.2 67.7 68.3 68.8 69.3 69.8 71-4 71.9 74.0 75-1 75.6 76.1 76.7 77-2 77-7 78.3 78.8 79-3 79.8 80.4 80.9 B1.4 82.0 82. 5 83.0 83.6 84.1 84.6 85.2 85.7 86.2 86.8 87.3 87.8 88.9 61 .0 61.6 62.1 62.6 63.1 63-7 64.2 64.7 65.2 65-7 66.3 66.8 67-3 67.8 68.4 68.9 69.4 70.0 70. S 71.0 71-5 72.1 72 .6 73.1 73.7 74.2 74.7 75-2 75-8 76.3 76.8 78.4 81.6 82.1 82.7 83.2 83.8 84.3 84.8 85.4 85-9 86.4 87.0 87. 5 89-7 6 rt 54.8 55-4 55-9 56.4 56.9 ■57'- 5 58.0 58.5 59-0 59-5 60. 1 60.6 61. 1 61:6 62.3 62 .7 63.2 63-7 64-3 64.8 65.3 65.8 66.4 06. 9 67.4 67.9 68.5 69.0 69. s 70.0 70.6 71. 1 74-8 75-3 75-9 76.4 76.9 77. 5 78.0. 78.5 79-' 79-6 80.1 80.6 81.2 81.7 82.3 82.8 83-3 O 223-2 223.8 224-5 22s. 2 225-9 226. 5 227.2 227.9 228. S 229.2 229.9 230.6 23I-2 231.9 232.6 233-3 233-9 234-6 235- 3 236.0 236.7 237.3 238.0 238.7 239.4 240.0 240.7 24I-4 242. I 242.7 243.4 244.1 244.8 245.4 246. 1 246.8 247.5 248. I 248.8 249. S 250. 2 250.8 351.5 252.2 252.9 253.6 254-2 254-9 255-6 256.3 256.9 2Sf7.6 258.3 259.0 2S9.6 229.0 229.7 230.4 231. 1 231.8 232. 5 233.2 233.9 234.6 235.3 235.9 236. 6 2-37 . 3 238.0 238.7 239.4 240. I 240.8 241 -5 242.2 242.9 243.6 244-3 245 -o 245.7 246.4 247.0 247.7 248.4 249.1 249.8 250.5 251.2 251.9 252.6 253.3 254-0 254-7 255-4 256. I 256.8 257-5 258. I 258.8 259.5 260.2 260.9 261 . 6 262.3 263.0 263.7 264.4 265. 1 265.8 366. S 234-9 235.6 236.3 237. (^ 237-8 238. S 239.2 239.9 240.6 241.3 242.0 242.7 243.4 244.1 244.8 245.6 246.3 247.0 247.7 248.4 249.1 249.8 2505 251.2 252.0 252.7 253.4 254-1 254-8 255-5 256.2 256.9 257-7 258.4 259.1 259 8 260. 5 261.2 261.9 262.6 263.4 264.1 264.8 265. S 266.2 266.9 367.6 268.3 269.0 269.8 370. s 371.3 271.9 273.6 273.3 o 267. 1 367.9 368.7 C69.S 270.3 271. 1 271.9 272.7 273-5 274.3 37S-0 375-8 276.6 277.4 278.2 279.0 279-8 280.6 281.4 283.2 282.9 283.7 284. 5 385.3 386.9 287.7 390.0 290.8 391 .6 2^2.4 293.2 394-0 294-8 295-6 296.4 397-2 297.9 298.7 299-5 300.3 301 . 1 301.9 303.7 303-5 304-2 3050 305-8 306.6 307-4 308.3 309.0 309-8 281. 2*2. 283. 283. 285.4 286.2 287.0 287.9 288.7 389.5 290.4 291 .3 293 .0 292.8 293-7 394-S 395-3 296. 2 297-0 297.8 298.7 399-5 ioo-3 301 .3 303.0 303.8 303-6 304-5 305-3 306.1 3070 307-8 308.6 309-5 310.3 3II-I 312.0 313.8 313-6 314-5 315 3 316.1 316.9 317-8 318.6 319-4 320.3 321. 1 321.9 322.8 3236 324.4 325.3 326.1 340 341 343 343 344 345 346 347 348 349 350 351 35* 353 354 35S 356 357 358 359 360 361 363 36J 364 36S 366 36* 369 370 371 37» 373 374 "I 370 378 379 380 381 381 383 384 38s 386 387 388 389 390 39« 391 393 394 220 APPENDIX MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIBE— (Continued) (Weights in Milligrams) Q Invert Sugar and Sucrose. Lactose. Maltose. q 3 3 o d ^^ V a ^rt j2 + 'S O "5 1 ^ & ^ + + 1 tn w Su W iT 3 a a a 2 3 u Q 1 gs B S 3 o. 3 0. 2§" 1 n K a n a a n a 3 O Q d « C u CJ 395 350. 9 185.7 191 .0 190.2 183-9 26a. 3. 267.2 274-0 310.6 336.9 395 396 351. 8 186.2 191 .6 190.7 184.4 261.0 267.9 274.7 311.4 327.7 396 397 352.6 186.8 192.x 191.3 184.9 261.7 268.6 275.5 312. 1 328.6 397 398 353-5 187.3 192.7 191.8 185. s 262.3 269.3 276.2 312.9 3294 398 399 354.4 187.8 193-3 192.3 186-0 263.0 269.9 276.9 313.7 330.2 399 400 335-3 188.4 193-7 192.9 186. s 263.7 270.6 277.6 314-5 331-1 460 401 356.2 188.9 194.3 194.8 193-4 187.1- 264.4 271-3 278.3 315-3 331-9 401 40J 357-1 189.4 194.0 187.6 265.0 272. 279.0 316-1 332.7 402 403 358.0 189.9 195-4 194-5 188.1 265.7 272.7 279.7 280.4 3i*-9 333.6 403 404 358.9 190.5 195-9 19S-0 188.7 266.4 273.4 317-7 334-4 404 40s 359.7 191. 196-4 195-6 189.2 267.1 274.1 281. I 3x8.5 335-2 40s 406 360.6 191. 5 197-P 196.1 189-8 267.8 274.8 281.9 319-2 336.0 406 407 361. S 192 . 1 197-5 196.7 190.3 268.4 275.5 282.6 320.0 336.9 407 408 362.4 192.6 198.1 197-3 190.8 269. 1 276.2 283.3 320.8 337-7 40S 409 363.3 193. 1 198.6 197-7 191.4 269.8 276.9 284.0 321. 6 338.5 409 410 364.2 193.7 199. 1 198.3 191.9 270. s 277.6 284.7 322.4 339.4 410 411 365-1 194.2 199.7 198.8 193. s 271.2 278.3 285.4 323-2 340.2 411 412 366.0 194.7 200.2 199.4 193.0 271.8 279,0 286.2 324.0 341.0 413 413 366.9 195-2 200.8 199.9 193-5 272. s 279.7 286.9 3248 341.9 413 414 367.7 I9S.& 201.3 aoo.s I94-I 273-2 280.4 287.6 325-6 343.7 414 415 368.6 196.3 30I.8 30I.0 194-6 273.0 281.1 288.3 326.3 343-5 41S 416 369-5 196.8 302.4 201 .6 195-3 274-6 281.8 289.0 337-x 344-4 416. 417 370.4 197.4 303 .9 202 . 1 195-7 275-2 282.5 289.7 327-9 345-2 417 418 371.3 197.9 303.5 202.6 196.2 275-9 283.2 290.4 328.7 346.0 418 419 372-3 198.4 204.0 203.3 196.8 276.6 283.9 291-2 329-5 346.8 419 4JO 373-1 199.0 204.6 303.7 197.3 277-3 284.6 291.9 330.3 347.7 420 421 374-0 199-5 205. 1 204.3 197.9 277.9 285.3 292.6 331-1 348. 5 421 422 374-8 aoo. I 205.7 204.8 198.4 278.6 286.0 293.3 331.9 349-3 422 423 375-7 200.6 206.2 205.4 198.9 279.3 286.7 294.0 332-7 350-2 423 424 376.6 201. 1 306.7 205.9 199.5 280.0 287.4 294.7 333-4 351.0 424 42s 377-5 201 .7 207.3 206.5 200.0 280.7 288.1 29S.4 334-2 351.8 425 426 378.4 202 .2 207.8 207.0 200.6 281 3 288.8 296.2 335.0 352.7 426 427 379-3 202.8 208.4 207.6 201 . 1 282.0 289,4 296.9 335.8 353-5 427 428 380.2 203.3 208.9 208.1 201.7 282.7 290. 1 297.6 336.6 354.3 438 429 381. 1 203.8 309. S 208.7 202 .3 283.4 290.8 298.3 337.4 355.1 439 430 382.0 204.4 210.0 209.2 202.7 284.1 291. S 299.0 338.2 356.0 430 431 382.8 204.9 210.6 209,8 203.3 284.7 292. 2 299-7 3390 356.8 43X 432 383.7 205.5 211 . I 210.3 203.8 285.4 292.9 300. s 339-7 357-6 433 433 384.6 206.0 211. 7 210.9 204.4 286.1 293.6 301.2 340. 5 358. 5 433 434 385.5 206. S 213.2 211.4 204.9 286.8 294.3 301.9 341-3 359-3 434 43 S 386.4 207. t 212.8 2ii .0 205. 5 287.5 295.0 302^.6 343.1 360. 1 436 436 387.3 207.6 213-3 313. 5 206.0 288.1 295.7 303.3 343.9 361.0 ••^z 388.2 208.2 313-9 313. I 206.6 288.8 296.4 304.0 343.7 361.8 ^^l 438 389-1 208.7 214-4 313-6 207.1 289. s 297- I 304.7 344. 5 362.6 438 439 390.0 209.3 215.0 214.3 i07.7 290.2 297.8 30s. S 345.3 363-4 439 440 390.8 209 8 •215.5 314.7 208. 3 290.9 298.5 306.2 346.x 364-3 440 441 391.7 310.3 216. 1 315-3 208.8 291. S 299. 2 306.9 346-8 365-1 441 442 392.6 210.9 216.6 315-8 209-3 192.3 299.9 367.6 347.6 365-9 443 443 393 -S 211 .4 217.3 216.4 209.9 292.9 300.6 308.3 348.4 366.8 443 444 394-4 212. 217.8 216.9 210.4 293.6 301.3 309.0 349-3 567-6 444 44S 395-3 212. S 218.3 217-5 211 .0 294-2 302.0 309.7 3SO.O 368.4 445 446 396.2 313. I 218.9 218.0 211. s 204 9 302.7 310.5 350.8 369 3 446 447 397-1 213-6 219.4 218.6 212 . 1 29S-6 303-4 311. B 351. 6 370.1 447 448 397-9 214 I 220.0 219. 1 212.6 296.3 304.1 3IJ.9 352.4 370.9 448 449 398.8 214.7 220.$ 319.7 313-.3 297-0 304.8 3X2.6 353 -3 371-7 44» TABLES 221 MUNSON AND WALKER'S TABLE FOR CALCULATING SUGARS FROM CUPROUS OXIDE— (Cotitimied) (Weights in Milligrams) q Invert Sugar and Sucrose. Lactose. Maltose. 3 3 y _ d ■8 ■a o 1 i 2 3 a. 0" ,+ d + V •0 ■a it si t. > a^ § S 6 d s a 3 0. s a ■ a X a 1 a o Q 6 " 450 399-7 215.2 221 . I 220.2 313.7 297.6 30s. s 313.3 353. 9 372.6 45a 451 400.6 215-8 221.6 220.8 214.3 298.3 306.2 314.0 354.7 373.^ 451 45» 401. 5 216.3 333. 2 321 -i 214..8 299.0 306.9 314.7 355. 5 374.3 452 453 402.4 316.9 222.-8 221 .9 215.4 299.7 307.6 315.5 356.3 375.1 453 4S4 403 -3 217.4 333.3 223. S 215.9 300.4 308.3 3l6.2 3S7-I 375.9 454 455 404.3 218.0 233.9 223.0 216. s 301. J 309.0 316.9 357-9 376.7 45S 456 405.1 218. s 324.4 223.6 217.0 301.7 309.7 317.6 358.7 377.6 456 457 405.9 219. 1 225.0 324.1 217.6 302.4 310.4 318.3 359. 5 378.4 457 458 406.8 219.6 225^5 334.7 318. 1 303.1 311. 1 319.0 360.3 379.2 458 459 407.7 220.3 226.1 335.3. 218.7 303.8 311. 8 319.8 361 ,0 380.0 459 460 408.6 220.7 226.7 225.8 219.2 304. s 312. S 320. s 361,8 380.9 460 461 409.5 221.3 227.2 226.4 219.8 30s -I 3Ii^2 321.2 362.6 381.7 461 46a 410.4 221.8 227.8 336.9 '!20.3 30s -8 313.9 321.9 363.4 382.5 462 463 411 -3 222.4 228.3 227.5 220 9 . 306. 5 314-6 322.6 364.2 383.4 463 464 412.2 323 .9 328 9 328.1 221.4 307.2 31S.3 323.4 365.0 384.2 464 46s 4130 223. 5 339. 5 228.6 222.0 307.9 316.0 324.1 365.8 385.0 46s 466 413-9 224,0 030:0 329.3 222.5 308.6 316.7 324.8 366.6 385.9 466 467 414-8 224.6 ' 330.6 339.7 223.1 309.2 317.4 32s- s 367.3 386.7 467 468 4IS-7 225 -t 231.2 230.3 223:7 309.9 318. 1 326.2 368.1 387-s 468 469, 416.6 335.7 ?3I.7 230.9 224.2 310.6 318.8 326.9 368.9 388.3 469 470 417. s 226. 2 232.3 231.4 434.8 311. 3 319, S 327.7 369.7 389-2 470 471 418.4 226.8 232.8 232.0 225-3 312.0 320.2 328.4 370.5 390.0 471 472 419-3 227.4 233.4 232.5 225-9 312.6 320.9 329.1 371.3 390.8 472 473 420.2 227-9 234.0 233-1 226.4 313-3 321 .6 329.8 372.1 391.7 473 474 421 .0 228 5 234. S 233.7 227.0 314.0 322.3 330. s 372,9 392. s 474 475 42 r . 9 229 ;23S.i 234.2 227.6 314.7 323.0 331.3 373.7 393-3 A^i 476 422.8 229.6 235.7 234.8 228.1 31S.4 323.7 332,0 374.4 394-2 476 477 423.7 230.1 236.2 235. 4 ,228.7 316. t 324.4 332.7 375.2 39S-0 477 478 424.6. 230.7 236.8 ' 235-9 229.3 316.7 32s. I 333.4 376.0 395-8 478 479 425 5 231.3 237-4 236. 5 229.8 317.4 325,8 334.1 376.8 396.6 479 480 426.4 T23I.8 237.9 237-1 230.3 318. 1 326. S 334.8 377.6 397.5 480 481 427-3 232.4 338.5 237-6 230.9 318.8 327.2 335.6 ■ 378.4 398.3 481 483 428.1 232 9 239.1 238.2 231. S 319 -S 327:9 336.3 3 79-2 399- > 483 483 429.0 233.5 239.6 238.8 232.0 320.1 328.6 337,0 380.0 400.0 483 484 429 9 234 I 240.3 239.3 232.6 320.8 329.3 337.7 380.7 400.8 484 48s 430.8 234.6 240.8 339.9 233.2 321. s 330.0 338.4 381. S 401 .6 *li 486 431 7 235.2 241.4 240.5 2337 322.2 30.7 Zi9.l 382.3 402.4 486 487 433.6 235.7 241.9 241 .0 234.3 322.9 331.4 339.9 383 . 1 403.3 *ll 488 433. 5 266.3 242.5 241 .6 234.8 323-6 332.1 340.6 385.9 404.1 488 489 434-4 236.9 243. « 243.2 ?35.4 324.2 332,8 341-3 384.7 404 -9 489 490 435 -3 237-4 243.6 242-7 236.0 324 9 333. S 342.0 385.5 405.8 490 222 APPENDIX EQUIVALENTS OF INDICES OF REFRACTION AND BUTYRO-REFRAC- TOMETER READINGS Refrac- Fourth Decimal o« tin tive - Index. "Z5. 1 2 3 4 5 6 7 8 9 SCALE READINGS 1.422 0.0 0.1 0.2 0.4 0-5 0.6 0.7 0.9 I.O I.I 1.423 1.2 1-4 1-5 1.6 1-7 1-9 2.0 2.1 2.2 2.4 1.424 2.5 2.6 2.7 2.8 3-0 3-1 3-2 3-3 3-5 3-6 1.425 3-7 3-8 4-0 4.1 4-2 4-3 4-5 4-6 4-7 4.8 1.426 5-0 S-i 5-2 5-4 S-S S-6 5-7 5-9 6.0 6.1 1.427 6.2 6.4 6-5 6.6 6.8 6.9 7.0 7-1 7-2 7-4 1.428 7-5 7-6 ■7-7 7-9 8.0 8.1 8.2 8.4 8-5 8.6 1.429 8,7 8.9 9.0 9.1 9-2' 9-4 9-5 9.6 9.8 9-9 1.430 10. 10. 1 10-3 10.4 lo.s 10.6 10.7 10.9 n.o 11.J I-43I 11-3 II. 4 "■5 ,11.6 II. 8 1 1.9 12.0 12.2 12-3 12.4 1.432 12.5 12.7 12.8 12.9 13-0 13-2 13-3 ^3-5 13.6 13.7 1-433 13-8 14.0 14. 1 14.2 14.4 14-5 14.6 14-7 14-9 15.0 1-434 .15.1 15-3 15-4 15-5 15-6 15-8 15-9 16.0 16.2 16.3 1-435 x6.4 16.6 16.7 16.8 17.0 17-1 17.2 17-4 17-5 17.6 1.436 17.8 17.9 18.0 18.2 18.3 18.4 18.5. 18.7 18.8 18.9 1-437 19. 1 19.2 19-3 19-S 19.6 19-7 19.8 20.0 20.1 20.3 1.438 ?o.4 20.5 20.6 20.8 20.9 21. 1 21.2 21.3 21.4 21.6 1-439 21.7 21.8 22.0 22.1 22.2 22.4 22.5 22.6 ■ 22.7 22.9 1.440 23.0 23.2 23-3 23-4 23-5 23-7 23.8 23-9 24.1 24.2 1. 441 24-3 24-5 24.6 24-7 24.8 2t;.o 25-1 25-2 25-4 25.5 1.442 25.6 25-8 25-9 26.1 26.2 26.3 26.S 26.6 26.7 26.9 1-443 27.0 27.1 27-3 27-4 27-5 27-7 27.8 27-9 28.1 28.2 1.444 28.3 28.S 28.6 28.7 28.9 29.0 29.2 29-3 29-4 29.6 1-445 29.7 29.9 30.0 30.1 30-3 30-4 30.6 30-7 30.8 30.9 1.446 31 -i 31.2 31-4 31-5 31.6 31-8 31-9 32-1 32.2 32-3 1.447 32-5 32.6 32.8 32-9 33-0 33-2 33-3 33-5 33-6 33.7 1.448 33 -J9 34-0 34-2 34-3 34-4 34.6 34-7 34-9 3S-0 35.1 1.449 35-3 35-4 35-6 35-7 35-8 36.0 36.1 36.3 36.4 36.5 1.450 36-7 36.8 37-0 37-1 37-2 37-4 37-5- 37-7 37-8 37-9 1.451 38.1 38-2 38-3 38.S 38-6 38.7 38-9 39-0 39-2 '39- 3r 1.452 39.-5 39-6 39-7 39-9 40.0 40.1 40.3 40.4 40.6 40.7 1-453 40.9 41.0 41. 1 41-3 41.4 41-5 41.7 41.8 42.0 42.1 1.454 42.3 42.4 42.5 42.7 42.8 43-0 ^^■1 43-3 ■ 43-4 43-6 I -455 43-7 43-9 44.0 44-2 44-3 44-4 44.6 44-7 44-9 45.0 1.456 45-2 45-3 45-5 45-6 45-7 45-9 46.0 46.2 46.3 46.4 1.457 46.6 46.7 46.9 47-0 47-2 47-3 47-5 47-6 47-7 47-9 1.458 48.0 48.2 48.3 48.5 48.6 48.8 48-9 49-1 49-2 49 4 1. 459 .49-5 49-7 49.8 50.0 SO. I 50.2 50.4 50.5 50-7 50.8 1.460 51.0 51.1 51-3 51-4 51.6 51-7 51-9 52-0 52.2 52-3 1.461 52-S 52.7 52-8 53-0 53-1 53-3 53-4 53-6 53-7 53-9 1.402 S4-0 54.2 54-3 54-5 54-6 54.8 55-0 55-1 55-3 55.4 1.463 55-6 55-7 55-9 56.0 56.2 56-3 56-5 56.6 56.8 56.9 1.464 57-1 57-3 57-4 ■ 57-6 57-7 57-9 58.0 58-2 58.3 58.5 i.465 58.6 58.8 58-9 59-1 59-2 59-4 59-5 59-7 59-8 60.0 1.466 60.2 60.3 60.5 60.6 60.8 60.9 61. 1 61.2 61.4 61.5 1,467 61.7 61.8 62.0 62.2 62.3 - 62.5 62.6 62.8 62.9 63.1 1.468 63.2 63-4 63 S 63-7 63.8 64.0 64.2 64-3 64-5 64.7 1.469 64.8 65.0 65.1 65-3 65.4 65.6 65-7 65-9 66.1 66.3 TABLES 223 EQUIVALENTS OF INDICES OF REFRACTION AND BUTYRO-REFRAC- TOMETER READINGS— {ConUnued) Refrac- Fourth Decimal of n^_ tive Index. *>D. 1 2 3 4 5 6 7 8 9 SCALE READINGS 1.470 66.4 66-5 66.7 66.8 67.0 67.2 67-3 67-5 67.7 67.8 1. 471 68.0 68.1 68.3 68.4 68.6 68.7 68,9 69.1 69.2 69.4 1.472 69-5 69.7 69.9 70.0 70.2 70-3 70.5 70.7 70.8 71.0 1-473 71. 1 71-3 71-4 71.6 71-8 71.9 72 I 72.2 72.4 72.5 1.474 72.7 72.9 73-0 73-2 73-3 73-5 73 7 73-8 74.0 74-1 I.47S 74-3 74-5 74.6 74-8 7.S-0 7S-I 75 i 75-5 75-6 75-8 1.476 76.0 76.1 76.3 76-S 76.7 76.8 77 77-2 77-3 77-S 1-477 77-7 77-9 78.1 78.2 78.4 78.6 78 7 78.9 79.1 79.2 1.478 79-4 79-6 79-8 80.0 80. 1 80.3 80 5 80.6 80.8 81.0 1.479 81.2 81.3 81.5 81.7 81.9 82.0 82 2 82.4 82.5 82.7 1.480 82.9 83.1 83-2 83-4 83.6 83.8 83 9 84.1 84-3 84-5 1. 481 84.6 84.8 85.0 85.2 85-3 85-5 85 7 85-9 86.0 86.2 1.482 86.4 86.6 86.7 86.9 87.1 87-3 87 5 87.6 87.8 88.0 1.483 88.2 88.3 88-5 88.7 88.9 89.1 89 2 89-4 89.6 89.8 1.484 90.0 90.2 9°-3 90-5 90.7 90.9 91 I 91.2 91.4 91.6 1,48s 91.8 92.0 92.1 92-3 92-5 92.7 92 9 93-0 93-2 93-4 1.486 93-6 93-8 94.0 94-1 94-3 94-5 94 7 94-8 95-0 95-2 1-487 95-4 9S-6 95-8 96.0 96.1 96-3 96 6 96.7 96.9 97.0 1.488 97-2 97-4 97-6 97.8 98.0 98.1 98 3 98.5 98.7 98-9 1.489 99.1 99.3 99.4 99.6 99.8 lOO.Q 224 APPENDIX GEERLIG'S TABLE FOR CALCULATING DRY SUBSTANCE OF SAC- CHARINE PRODUCTS FROM REFRACTIVE INDEX AT 28° C. Find in the table the refractive index which is next lower than the reading actually made. and note the corresponding whole number for the per cent of dry- substance. Subtract the refractive index obtained from the table from the observed reading; the decimal corresponding to this difference, as given in the column so marked, is added to the whole per cent of dry substance as first obtained. Per Per Refrac- Cent Decimals to be Added for Refrac- Cent Decimals to be Added for tive Dry Fractional Readings. tive Dry Fractional Readings. Index. Sub- stance. Index. Sub- stance. 1-3335 I 0.0001=0.05 0.0010=0.75 1.4083 45 0.0004 = 0.2 0.0015 = 0.75 1-3349 2 0.0002 = 0.1 0.0011 = 0.8 1.4104 46 0.0005 = 0.25 0.0016 = 0.8 1-3364 3 0.0003 = 0.2 0.0012 = 0.8 I. 4124 47 0.0006 = 0.3 0.0017 = 0.85 1-3379 4 0.0004 = 0.25 0.0013 = 0.85 I. 4145 48 0.0007 = 0.35 0.0018 = 0.9 1-3394 5 0.0005 = 0.3 0.0014 = 0.9 I. 4166 49 0.0008 = 0.4 0.0019=0.95 1-3409 6 0.0006 = 0.4 0.0015=1.0 1.4186 50 0.0009 = 0.45 0.0020=1.0 1.3424 7 0.0007 = 0.5 1.4207 51 0.0010 = 0.5 0.002I = I.O 1-3439 8 0.0008 = 0.6 1.4228 52 0.0011 = 0.55 1-3454 9 0.0009=0.7 1.4219 53 1.3469 10 1.4270 54 1.3484 11 0.0001 = 0.05 1.4292 55 0.0001 = 0.05 0.0013 = 0.55 1-3500 12 0.0002 = 0.1 1-4314 56 0.0002 = 0.1 0.0014=0.6 1-3516 13 0.0003 = 0.2 1-4337 57 0.0003 = 0.1 0.0015 = 0.65 1-3530 14 0.0004 = 0.25 1-4359 58 0.0004 = 0.15 0.0016 = 0.7 1-3546 IS 0.0005 = 0.3 1.4382 59 0.0005 = 0.2 0.0017 = 0.75 1-3562 16 0.0006 = 0.4 I -4405 60 0.0006 = 0.25 0.0018 = 0.8 1-3578 17 0.0007 = 0.45 1.4428 61 0.0007 = 0.3 0.0019 = 0.85 1-3594 18 0.0008 = 0.5 1-4451 62 0.0008 = 0.35 0.0020=0.9 1.3611 19 0.0009 = 0.6 1.4474 63 0.0009 = 0.4 0.0021=0.9 1.3627 20 0.0010 = 0.65 1.4497 64 0.0010 = 0.45 0.0022 = 0.95 1.3644 21 0.0011 = 0.7 1.4520 65 0.0011 = 0.5 0.0023=1.0 1.3661 22 0.0012 = 0.75 1-4543 66 0.0012 = 0.5 0.0024=1.0 1.3678 23 0.0013 = 0.8 1.4567 67 1-3695 24 0014 = 0.85 I -4591 68 I. 3712 25 0.0015 = 0.9 _ I. 4615 6^ 1-3729 26 0.0016 = 0.95 1.4639 1.4663 1.4687 70 71 72 1-3746 1-3764 27 28 0.0001 = 0.05 0.0012 = 0.6 0.0013 = 0.65 0.0002 = 0.1 1.3782 29 0.0003 = 0.15 0.0014=0.7 1.4711 73 0.0001 = 0.0 0.0015=0.55 1 . 3800 30 0.0004 = 0.2 0.0015 = 0.75 1-4736 74 0.0002 = 0.05 0.0016 = 0.6 1.3818 31 0.0005 = 0.25 0.0016 = 0.8 1.4761 75 0.0003 = 0.1 0.0017 = 0.65 1-3836 32 0.0006 = 0.3 0.0017 = 0.85 1.4786 76 0.0004 = 0.15 0.0018 = 0.65 1-3854 33 0.0007 = 0.35 0.0018 = 0.9 1.4811 77 0.0005 = 0.2 0.0019=0.7 1-3872 34 0.0008 = 0.45 0.0019=0.95 1.4836 78 0.0006 = 0.2 0.0020=0.75 1-3890 35 0.0009 = 0.4 0.0020=1.0 1.4862 79 0.0007 = 0.25 0.0021=0.8 1-3909 36 0.0010 = 0.5 0.0021 = 1.0 1.4888 80 0.0008 = 0.3 0.0022 = 0.8 1.3928 37 0.0011 = 0.55 1.49x4 81 0.0009=0.35 0.0023 = 0.851 1-3947 38 1.4940 82 0.0010=0.35 0.0024 = 0.9 1-3966 39 1.4966 83 0.0011 = 0.4 0.0025 = 0.9 1-3984 40 1.4992 84 0.0012 = 0.45 0.0026=0.95 1-4003 41 1.5019 85 0.0013 = 0.5 0.0027= 1.0 I - 5046 86 0014 = 0.5 0.0028=1.0 1-5073 87 1.4023 42 0.0001 = 0.05 0.0012 = 0.6 1.5100 88 1-4043 43 0.0002 = 0.1 0.0013 = 0.65 1.5127 89 1.4063 44 0.0003 = 0.15 0.0014 = 0.7 1.5155 90 • TABLES 225 TEMPERATURE CORRECTIONS FOR USE WITH GEERLIG'S TABLE, PAGE 224 Tempera- Dry Substance. ture of the Prisms in 5 xo •5 20 25 1 30 1 40 ! so 60 70 80 90 "C. Subtract — 20 0-53 0.54 55 0.56 0.57 0.58 0.60 0.62 0.64 0.62 0.61 0.60 0.58 21 .46 • 47 4« • 49 •50 •51 .52 • 54 •Sb •54 •S3 •52 •50 22 .40 -41 42 • 42 .43 .44 .45 ■47 .48 •47 .40 • 45 • 44 23 .33 •33 34 •35 .3f •37 •38 •39 .40 •39 .38 •38 •38 24 .26 .26 27 .28 .28 .29 •30 •31 •32 •31 •31 •30 -30 "5 .20 .20 21 .21. .22 .22 •23 .23 • 24 •23 •23 •23 .22 26 .12 .12 13 .14 .14 • 15 • 15 .16 -lO .16 • 15 • 15 • 14 27 .07 .07 07 .07 •07 -07 .08 .08 .08 .08 .08 .08 .07 Add— 29 0.07 D.07 07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.07 30 .12 .12 13 • 14 .14 • 14 •IS •15 ^16 .16 .16 .15 ■14 31 ■.20 .20 21 .21 .22 .22 •23 •23 • 24 •23 •23 .23 .22 32 .26 .26 27 .28 .28 .29 •30 •31 •32 •31 •31 •30 -30 33 •33 •33 34 -35 •30 •37 •38 •39 .40 •39 •3« -38 .38 34 .40 • 41 42 • 42 •43 • 44 •45 -47 .48. •47 .40 -45 -44 35 .46 •47 .48 -49 •50 •51 -52 •54 ■50 ■ 54 .53 -52 •50 226 APPENDIX HEHNER'S TABLE FOR CALCULATING ALCOHOL FROM SPECIFIC GRAVITY — Absolute Alcohol. Spec. Absolute Alcohol. Spec. Absolute Alcohol. Spec. Grav. at Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Eei Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams 15.6° C. by Weight by Vol- ume. per 100 cc. by Weight by Vol- ume. per too cc. by Weight by Vol- ume. per 100 cc. I. 0000 0.00 0.00 0.00 0.9999 0.05 0.07 0.05 a- 9959 2.33 2-93 2.32 0.9919 4.69 5-86 4-65 8 O.II 0.13 O.II 8 2-39 3.00 2-38 8 4-75 5-94 4.71 7 o.t6 0.20 0.16 7 2.44 3-07 2-43 7 4.81 6.02 4-77 6 0.21 0.26 0.21 6 2.50 3-14 2-49 6 4-87 6.10 4-83 5 0.26 0.33 Q.26 5 2.56 3-21 ^-55 5 4-94 6.17 4.90 4 0.32 0.40 0.32 4 2.61 3-28 2.60 4 5.00 6.24 4-95 3 0.37 0.46 0-37 3 2.67 3-35 2.6s 3 5.06 6.32 5-OI 2 0.42 0-S3 0.42 2 2.72 3-42 2.70 2 5-12 6.40 5-07 I 0.47 0.60 0.47 I 2.78 3-49 2.76 I 5-19 6.48 5.- 14 0-53 0.66 0-53 2-83 3-55 2.81 s-25 6-55 5.20 0.9989 0.58 0-73 0-58 0-9949 2.89 3.62 2.87 0.9909 5-3' 6.63 5.26 8 0.63 0.79 0.63 8 2.94 3-69 2.92 8 5-37 6.71 5-32 7 0.68 0.86 0.68 7 3.00 3.76 2.98 7 5-44 6.78 5-39 6 0.74 0.93 0.74 6 3.06 3-83 3-04 6 5-50 6.86 5-45 S 0.79 0.99 0.79 5 3.12 3-90 3.10 5 5-56 6.94 5-51 4 0.84 1.06 0,84 4 3-18 3-98 3.16 4 5.62 7.01 5-57 3 0.89 I -13 0.89 3 3-24 4-05 3.22 3 5-69 7.09 5-64 3 0.95 1. 19 0-9S 2 3-29 4.12 3-27 2 5-75 7.17 5-70 I 1. 00 1.26 1. 00 ■I 3-35 4.20 3-33 1 5-81 7-25 5-76 1.06 1-34 1.06 3-41 4.27 3-39 5-87 7-32 S-8i 0.9979 1. 12 1.42 1. 12 0.9939 3-47 4-34 3-45 0.9899 5-94 7.40 5-88 8 1.19 1.49 1. 19 8 3-53 4-42 3-51 8 6.00 7.48 5-94 7 1. 25 1-57 1-25 7 3-59 4-49 3-57 7 6.07 7-57 6.01 6 1-31 1.65 1-31 6 3-65 4-56 3-63 6 6.14 7.66 6.07 5 1-37 1-73 1-37 5 3-71 4-63 3.69 5 6.21 7-74 6.14 4 1-44 1. 81 1-44 4 3-76 4.71 3-74 4 6.28 7-83 6.21 3 1.50 1.88 1.50 3 3-82 4.78 3-80 3 6.36 7-92 6.29 2 1.56 1.96 1-56 2 3-88 4-85 3-85 2 6.43 8.01 6.36 1 1.62 2.04 i.6t I 3-94 4-93 3-91 I 6.50 8.10 6.43 1.69 2.12 1.68 4.00 5.00 3-97 6-57 8.18 6.50 0.9969 I-7S 2.20 1-74 0.9929 4.06 5-08 4-03 0.9889 6.64 8.27 6.57 8 1.81 2.27 1.80 8 4.IZ 5-16 4.09 8 6.71 8.36 6.63 7 1.87 2-35 1.86 '7 4.19 S-24 4.16 7 6.78 8.45 6.70 6 1.94 2-43 1-93 6 4-25 5-32 4.22 6 6.86 8.54 6.78 5 2.00 2-51 1-99 5 4-31 5-39 4.28 5 6-93 8.63 6.8s 4 2.06 2.58 2.05 4 4-37 5-47 4-34 4 7.00 8.72 6.92 3 2. II 2.62 2.10 3 4-44 5-55 4.40 3 7.07 8.80 6-99 2 2.17 2.72 2.16 2 4-50 5-63 4.46 2 7-13 8.88 7-05 I 2.22 2-79 2.21 I 4-56 5-71 4-52 I 7 20 8.96 7.12 2.28 2.86 2.27 4.62 5-7^ 4-58 7.27 9.04 7.19 TABLES 227 HEHNER'S TABLE FOR CALCULATING ALCOHOL FROM SPECIFIC GRAVITY— (Continued) Spec. Absolute AlcohoL Spec. Absolute Alcohol. Spec. Absolute AlcohoL Grav. at Per Cent Per Cent Grams Grav. at IS.6°C Per Cent Per Cent Grams Grav. at Per Cent Per Cent Grams 15.6° C. by by Vol- per by by Vol- per 100 c6. iS-^'C by by Vol per Weight ume. 100 cc. Weight ume. Weight ume. 100 cc 0.9879 7-33 9-13 7.24 0.9829 10.92 13-52 10-73 0.9779 14.91 18. 3« 14-58 8 7.40 9.21 7-31 8 n.oo 13.62 ^0.81 8 15.00 18.48 14.66 7 7-47 9.29 7-37 7 11.08 13-71 10.89 7 15.08 18.58 14-74 6 7-53 9-37 7-43 6 II. 15 13-81 10.95 6 15-17 18.68 14-83 5 7.60 9-45 7-50 5 11.23 13.90 11.03 5 15-25 18.78 14.90 3 7.67 9-54 7-57 4 II. 31 13-99 II. 11 4 15-33 18.88 14.98 7-73 9.62 7-63 3 11.38 14.09 11.18 3 15-42 18.98 15-07 2 7.80 9.70 7.70 .2 11.46 14.18 11.26 2 15-50 19.08 15-14 I 7.87 9.78 7-77 'i 11-54 14.27 11-33 I IS-58 19.18 15.21 7-93 9.86 7-83 11.62 14-37 II. 41 15-67 19.28 15-30 0.9869 8.00 9-95 7-89 0.9819 11.69 14.46 11.48 0.9769 15-75 19-39 IS -38 8 8.07 10.03 7.96 8 11.77 14.56 11.56 8 15-83 19.49 15-46 7 8.14 10.12 8.04 7 11.85 14.65 11.64 7 15-92 19-59 15.54 6 8.21 10.21 8.10 6 11.92 14-74 11.70 6 i6;Oo 19.68 15.63 s 8.29 10.30 8.17 5 12.00 14.84 11.78 5 16.08 19.78 15-70 4 8.36 10.38 8.24 4 12.08 14-93 11.85 4 16.15 19.87 15-76 3 8.43 10.47 8.31 3 12.15 15.02 11.92 3 16.23 19.96 15-84 2 8.50 10.56 8.38 2 12.23 15.12 12.00 2 16.31 20.06 15-90 I 8-57 10.65 8.45 I 12.31 15.21 12.08 I 16.38 20.15 15-99 8.64 10-73 8-52 12.38 ;i5-30 12.14 16.46 20.24 16.06 0.9859 8.71 .10.82 8.58 0.9809 12.46 15-40 12.22 0.9759 16.54 20.33 16.13 8 8.79 10.91 8.66 8 12.54 15-49 12.30 8 16.62 20.43 16. 21 7 8.86 11.00 8.73 7 12.62 15-58 12.37 7 16.69 20.52 16.28 6 8-93 11.08 8.80 6 12.69 15.68 12.44 6 16.77 20.61 16.35 5 9.00 11.17 8.87 5 12.77 15-77 12.51 5 16.85 20.71 16.43 4 9.07 11.26 8-93 4 12.85 15.86 12-59 4 16.92 *o.8o 16.50 3 9.14 "-35 9.00 3 12.92 15.96 12.66 3 17.00 20.89 16.57 9.21 11.44 9.07 2 13.00 16.05 12.74 2 17.08 20.99 16.65 I 9.29 11.52 9.14 I 13.08 16.15 12.81 I 17.17 21.09 16.74 9-36 II. 61 9.22 13-15 16.24 12.89 17-25 21.19 16.81 0.9849 9-43 11.70 9.29 0.9799 13-23 »6.33 12.96 0.9749 17-33 21.29 16.89 8 9-50 11.79 9-35 8 13-31 16.43 13-03 8 17.42 21.39 16.97 7 9-57 11.87 9.42 7 13-38 16.52 13.10 7 17-50 21.49 17-05 6 9.64 11.96 9-49 6 13-46 16.61 i3-;i8 6 17.58 21-59 17.13 5 9.71 12.05 9-56 5 13-54 16.70 13.26 5 17.67 21.69 17.20 4 9-79 12.13 9.64 4 13.62 16.80 ^3-33 4 17-75 21.79 17.29 3 9.86 12.22 9.71 3 13.69 16.89 13-40 3 ^7-83 21.89 17 37 17-46 3 9-93 12.31 9-77 2 13-77 16.98 13-48 2 17.92 21.99 I ro.oo 12.40 9-84 I 13-85 17.08 13-56 I 18.00 22.09 17-54 10.03 12.49 9-92 13.92 17.17 13-63 18.08 22.18 17.61 0.9839 10.15 12.58 9-99 0.9789 14.00 17.26 ;3-7i 0.9739 18.15 2^.27 17.68 17-76 17.82 8 10.23 12.68 10.06 8 14.09 17-37 13-79 8 18.23 22.36 7 10.31 12.77 10.13 7 14.18 17-48 13.88 7 18.31 22.46 6 10.38 12.87 10.20 6 14.27 17-59 13.96 6 18.38 22.55 17.90 5 10.46 12.96 10.28 5 14.36 17.70 14.04 5 18.46 22.64 17-97 18.05 18.13 18.19 18.27 18.34 4 10.54 13-05 10.36 4 14-45 17.81 14-13 4 18.54 22.73 3 10.62 13-15 10.44 3 14-55 ir.92 14-23 3 18.62 22.82 2 ro.69 13-24 10.51 2 14.64 18.03 '4-32 2 18.69 22.92 I ip.77 13-34 IO-59 •1 14-73 18.14 ^4-39 1 18.77 23.01 10.85 13-43 10.67 14.82 18.25 14.48 18.85 2I.I<5 228 APPENDIX HEHNER'S TABLE FOR CALCULATING ALCOHOL FROM SPECIFIC G1^\\ITY— {Continued) Absolute Alcohol. Spec. Absolute Alcohol. Spec. Absolute Alcohol. Spec. 1 Grav. at Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams ts.e'C. by by Vol- per by by Vol- per by by Vol- per Weight ume. 100 cc. Weight ume. 100 cc. Weight vune. 100 cc. 0.9729 18.92 23-19 18.41 0.9679 22.92 27-95 22.18 0.9629 26.60 32.27 25.61 8 19.00 23.18 18.48 8 23.00 28.04 22.26 8 26.67 32-34 25.67 7 19.08 23-38 18.56 7 23-08 28.13 22.33 7 26.73 32.42 35-73 6 19.17 23-48 18.65 6 23-15 28.22 22.40 6 26.80 32-50 25-79 S 19-25 23-58 18.73 5 23-23 28.31 22.47 5 26.87 32-58 35-85 4 19-33 23.68 18.80 4 23-31 28.41 22.54 4 26.93 32-65 25-91 i 19-42 , 23-7» 18.88 3 23.38 28.50 22.61 3 27.00 32-73 25.98 2 19-5° 23.88 18.95 2 23.46 28.59 22.69 2 27-07 32..81 26.04 I 19-58 23.98 19-03 I 23-54 28.68 22.76 I 27.14 32-90 26,10 19.67 24.08 19.12 23.62 28.77 22.83 27.21 32.98 26.17 0.9719 19-75 24.18 19.19 0.9669 23.69 28.86 22.90 0.9619 27-29 33-06 36.25 8 19-83 24.28 19-27 8 23-77 28.95 22.97 8 27-36 33-15 26.31 7 19.92 24-38 19-36 7 23-85 29.04 23-05 7 27-43 33-23 26.37 6 20.00 24-48 19.44 6 23-92 29-13 23.11 6 27-50 2,3-3^ 26.43 5 20.08 ^4-58 19-51 5 24.00 29.22 23-19 S 27-57 33-39 26.51 4 20.17 24.68 J9-59 4 24.08 29.31 23-27 4 27.64 33-48 26.57 3 20.25 24-78 19.66 3 24-15 29.40 23-33 3 27.71 33-56 26.64 2 20.33 24.88 19-74 2 24-23 29-49 23-40 2 27-79 33-64 26.71 I 20.42 24.98 19.83 I 34-31 29-58 23-48 I 27.80 33-73 26.78 20.50 25.07 19.90 24-38 29.67 23-55 27-93 33-81 26.84 0.9709 20.58 25-17 19.98 0.9659 24.46 29.76 23.62 0.9609 28.00 33-89 26.90 8 20.67 25-27 20.07 • 8 24-54 29.86 23-70 8 28.06 33-97 ^6.96 7 20.75 25-37 20.14 7 24.62 29-95 23-77 7 28.12 34-04 27.01 6 20.83 25-47 20.22 6 24-69 30.-04 23.84 6 28.19 34-11 27-07 5 20.92 25-57 20.30 5 24-77 30-13 23-91 5 28.25 34.18 27-13 4 21.00 25-67 20.33 4 24-85 30.22 23-99 4 28.31 •34-25 27.18 3 21. oS 25-76 20.46 3 24.92 30-31 24-05 3 28.37 34-33 27.24 2 21.15 25-86 20.52 2 25.00 30.40 24.12 2 28.44 34-40 27-3J I 21.23 25-95 20.59 1 25-07 30.48 24.19 I 28.50 34-47 27.36 21.31 26.04 20.67 25-14 30-57 24.26 28.56 34-54 37-43 0.9699 21.38 26.13 20.73 0.9649 25.21 30.65 24-32 0.9599 28.62 34-6i 37-47 8 21.46 26.22 20.81 8 25.29 30.73 24-39 8 28.69 34-69 27-53 7 21.54 26.31 20.89 7 25-36 30.82 24-46 7 28.75 34-76 37-59 6 21.62 26.40 20.96 6 25-43 30.90 24-53 6 28.81 34-83 27.64 5 21.69 26.49 21.03 5 25-5° 30.98 24-59 5 28.87 34-90 27.70 4 21.77 26.58 21.11 4 25-57 31-07 24.66 4 28.94 34-97 27.76 3 21.85 26.67 21.18 3 25.64 i^'-^z 24.72 3 29.00 35-05 27.82 2 21.92 26.77 21.25 2 25-71 iT--^i 24.79 2 29.07 35-12 27.89 I 22.00 26.86 21-33 I 25-79 Zi^-3^ 24.86 1 29-^3 35-20 27-95 22.08 26.95 21.40 25.86 31.40 24-93 29.20 35-28 28.00 D.9689 22.15 27.04 21.47 0.9639 25-93 31-48 24.99 0.9589 29.27 35-35 28.07 8 22.23 27-*'3 21-54 8 26.00 31-57 25.06 8 29-33 35-43 28.12 7 22.31 27.22 21.61 7 26.07 31-65 25.12 7 29-40 35-51 28.18 6 22.38 27-31 21.68 6 26.13 31-72 25.18 6 29-47 35-58 28.24 5 22.46 27.40 21.76 5 26.20 31.80 25-23 S 29-53 35-66 28.30 4 22.54 27.49 21.83 4 26.27 31.88 25-30 4 29.60 35-74 38.36 3 22.62 27-59 21.90 3 26.33 31.96 25-36 3 29.67 35-81 28.43 2 22.69 27.68 21.96 2 26.40 32-03 25-43 2 29-73 35-89 28.48 I 22.77 27-77 22.01 1 26.47 32.11 25-49 I 29.80 35-97 28.54 22.85 27.86 22.12 26.53 32.19 25-55 29.87 36.04 28.61 TABLES 229 HEHNER'S TABLE FOR CALCULATING ALCOHOL FROM SPECIFIC GRAVITY— iConti7ttied) Spec. Grav. at i5 56 vegetables, 45, 55, 56 Fats, see Oils. Fatty acids, see Acids, fatty. Fehling solution, 75, 76 Fiber, crude, constituents, 59 determination, 60 in cocoa products, 210 coffee, 206 fruit products, 162 fruits, 45, 59, 60 mill products, 44, 59, 60 nuts, 45, 59, 60 spices, 46, 59, 60 tea, 208 vegetable foods, 2, 41, 59, 60 vegetables, 45, 59, 60 Fibro-vascular bundles, 115 Fish, I, ss composition of, 34, 35 Flavoring extracts, 179 Flax seed, see Linseed. Flour, absorption of, 77 acidity of, 77 analysis of, 77 baking tests of, 77 buckwheat, composition of, 44 microscopy of, 103, 124 composition of, 44 graham, composition of, 44 rye, composition of, 44 Flour, rye, microscopy of, 99, 124 wheat, color value of, 77 composition of, 44 fat, chlorine in, 77 iodine number of, 77 gluten in, 77, 99 microscopy of, 99, 124 nitrites in, 77 starch in, 44, 75 Folin and Denis vanillin method, 192 Food analysis, limitations, 5 literature, 5 province, 5 chopper, 48 technology literature, 6 Foods, animal, i microscopy of, 83 mineral, 4 vegetable, 2, 41 Force, composition of, 44 Fore milk, 1 2 Foreign leaves in tea, 208 Formaldehyde in milk, 20 Fowls, composition of, 35 Fructose, d, see Levulose. Fruit juices, acidity of, 168 solids in, 164, 166 sugar in, 163, 167 products, 162 analysis of, 164, 177 preservatives in, 177 syrups, colors in, 137, 138 Fruits, 2, 43, 45, 162 analysis of, 43, 163 canned, 177 composition of, 45 dried, 177 Funnel, separatory, 185 Furfural in liquors, 1 70 Fusel oil in liquors, 1 70 G Gasoline color value of flour, 77 Gelatin, 33 Ginger, composition of, 46 microscopy of, 116, 125 Gliadin, 98 INDEX 245 Globoids, 112 Glucose, commercial, 133 d, see Dextrose. Gluten, 77, 98 Glutinin, 98 Glycerol in fats, 139 liquors, 170 Glycogen, i, 33 Gooch crucible, 27, 28 Graham flour, composition of, 44 Grape nuts, composition of, 44 Grapes, composition of, 45 Green corn, composition of, 45 Grits, composition of, 44 Guanine, ^s Gums, 2, 74 Gunning -Arnold-Kjeldahl method, 72 H Hairs, 97, loi, 108, 122 Halibut, composition of, 35 Halphen cotton seed oil test, 150 Hanus iodine number method, 152 Henneberg crude fiber method, 60 Hess and Prescott vanillin and cou- marin method, 184 Hiltner citral method, 198 Hominy, composition of, 44 Homogenized oils, 31 Honey, invert sugar in, 133 polarization of, 134 solids in, 135 Hiibl iodine number method, 152 Hypogaeic acid, 140 Ice cream, 30 analysis of, 31 colors in, 31 fat in, 31 homogenized oils in, 31 preservatives in, 31 thickeners in, 31 Insoluble fatty acids, 160 Intercellular spaces, 98, 122, 123 Inversion of sucrose, 131, 134 Invert sugar, copper reduction by, 128, 167 determination, 131, 161, 213 Iodine number, 3, 152 Iso-oleic acid, 140 Jellies, 177 Johnson fat extractor, 21, 22, 56, 57 Kjeldahl apparatus, 65, 66 KJeldahl nitrogen method, 65 Koettstorfer saponification number method, 155 La Wall and Bradshaw benzoate method, 178 Lactic acid, 29 Lactometer, 14 Lactose determination, 26, 213 in milk, i., 26 Lard, 143, 145, 150 Laurie acid, 140 Leach coumarin test, 189 Lead number, 136 Leaves, foreign, in tea, 208 spent, in tea, 208 Lecithin, i Leffmann and Beam volatile fatty acids method, 157 Legumes, 2, 64 Lemon extract, 196 alcohol in, 200 aldehydes in, 200 citral in, 198 colors in, 200 composition of, 197 lemon oil in, 197, 198 practice material, 197 terpeneless, 197 oil, 196 in lemon extract, 197, 198 terpeneless, 197 Lettuce, composition of, 45 Levulose, 127, 128 246 INDEX Lignin, 2, 59 Lignoceric acid, 140 Limonene, 196 Linolic acid, 140 Linseed meal, composition of, 44 microscopy of, no, 124 microscopy of, no oil, 140, 152 Liquors, 162 distilled, composition, 170, 171 malt, composition, 170, 171 preservatives in, 170 wood alcohol in, 170 Lists, apparatus, 231 practice material, 237 reagents, 235 Lobster, composition of, 35 Lovibond tintometer, 189 M Mace, composition of, 46 Maize, see Corn. Malic acid, 162 Malt liquors, see Liquors. Maltase, 168. Maltose, 75, 168, 213 Maple products, 135 Material, practice, 237 alkaloidal products, 42, 93, 205 baking powders, 79 dairy products, 14, 26 fats and oils, 142 flavoring extracts, 183, 197 fruit products, 165 list, 237 meat, 38 microscopic, 92, 93 mill products, 42, 93 saccharine products, 133, 136 spices, 42, 93 starches, 92 Maumene test for oils, 160 Meal, corn, composition of, 44 microscopy of, 102, 124 cotton seed, composition, 44 microscopy of, 106 linseed, composition of, 44 Meal, linseed, microscopy of, no oat, composition of, 44 microscopy of, loi, 124 Meat, I, S3, 34, 35 analysis, 34 composition of, 34, 35 extracts, 34 Melting-point of coumarin, 188 fats, 159 Methods, see Determination and Test. Micrometer, 85 calibration of, 86 Microscope, 84 Chamot polarizing, 85 construction of, 84 Microscopic accessories, 85 mount, 87, 88 Microscopy of bean starch, 93 buckwheat, 103, 124 cassava starch, 93 cinnamon, 115, 124, 125 cocoa, 120, 125 coffee, 118, 125 corn, loi starch, 93, 103, 124 cotton seed, 106 ginger, 116, 125 linseed, no oat starch, 93, 1 24 oats, 100 peas, 105, 124, 125 pepper, black, 112, 124, 125 Cayenne, 114, 125 white, 112, 124, 125 potato starch, 93 rye, 99, 124 starches, 88 tea, 122 vegetable foods,, 83, 93 wheat, 94, 124 starch, 93, 98, 124 Milk, n analysis, 14, 15, 16, 18, 21, 25 boron compounds in, 25 chocolate, 209 composition, colostrum, 12 cow's, II INDEX 247 Milk, composition, goat's, ii woman's, ii condensed, see Condensed milk. fat in, 18, 21 fore, 12 formaldehyde in, 20 lactose in, 26 preservatives in, 20, 25 protein in, 25 sampler, 13 sampling, 13 specific gravity, 14 standards, 12 strippings, 12 total solids in, 15, 16, 25 MiU products, 41 ash in, 72, 73 composition of, 44 crude fiber in, 59, 60 fat in, 55, 60 nitrogen-free extract in, 74 pentosans in, 77 protein in, 63, 65 starch in, 75 water in, 50, 52 Mince meat, 177 Mineral foods, 4 Mitchell lemon oil methods, 198 Moisture, see Water. Molasses, analysis of, 133 solids in, 135 sucrose in, 133 Mortar, iron, 49 Mounting, 87 Munson and Walker sugar method, 76 table, 213 Muscle fiber, ^^ Mustard oil, 140, 155 Mutton, composition of, 35 tallow, 143 Mycoderma acdl, 1 75 Myosin, 33 Myristic acid, 140 N Nitrates in wine, 170 Nitrites in flour, 77 I Nitrogen, see Protein. Nitrogen-free extract, constituents, 2 determination, 74 in cocoa products, 210 coflfee, 206 fruit products, 162 fruits, 45, 74 miU products, 44, 74 nuts, 45, 74 tea, 208 vegetable foods, 2, 41, 44, 45, 74 vegetables, 45, 74 Normal lead number of vanilla extract, 191 Nutmegs, composition of, 46 Nutrition, 6 literature, 6 Nuts, 2, 43, 45 analysis of, 43 composition of, 45 O Oat meal, composition of, 44 microscopy of, loi, 124 starch, 90, 93, loi, 124 Oats, microscopy of, 100, 124 Oil, cocoanut, 140, 143, 157 cotton seed, 106, 140, 143, 150, 161 lemon, 196 terpeneless, 197 linseed, 106, 140, 152 mustard, 140, 155 olive, 140, 143 palm nut, 140, 152 peanut, 140, 143, 151 poppy seed, 140 rape, 140, 155 seed products, 42, 44, 106 analysis of, 42 composition of, 44 seeds, 2, 106 sesame, 140, 143, 151 sunflower, 140 whale, 161 Oils and fats, 139 acetyl value of, 160 248 INDEX Oils and fats, acids of, 140 Baudouin test, 151 bromination test, 160 cholesterol in, i, 161 constants of, 141, 143 constituents of, 139 cotton seed oil in, 150 halogenation of, 139, 152 Halphen test, 150 Hanus number of, 152 hydrogenation of, 161 insoluble fatty acids in, 160 iodine number of, 3, 152 Koettstorfer number of, 155 literature of, 6 Maumene test, 160 melting-point of, 159 oxidation of, 139 Polenske number of, 159 practice material, 142 qualitative tests, 150, 151 refractive index of, 3, 146 Reichert-Meissl number of, 157 saponification number of, 3, 155 saponification of, 140 sesame oil in, 151 sitosterol in, 3, 161 soluble fatty acids in, 160 specific gravity of, 144 titer test of, 160 unsaponifiable matter in, 161 volatile fatty acids in, 3, 31, 157 Oils, essential, see Essential Oils. Oleic acid, 139, 140 Olive oil, 140, 143 Onions, composition of, 45 Orange extract, 200 Oranges, composition of, 45 Oven, water, 17 Oysters, composition of, 35 Palisade cells, 105, 108 Palm nut oil, 140, 152 test for, 152 Palmitic acid, 139, 140 Pancreatin, 75 Patrick test for ice cream thickeners, 31 Paul method for ice cream fat, 31 Peaches, composition of, 45 Peanut butter, composition of, 44 oil, 140, 151 constants of, 143 test for, 152 Peanuts, composition of, 45 Peas, microscopy of, 105, 124, 125 green, composition of, 45 Pecans, composition of, 45 Pentosans, 3, 75, 77 Pepper, black, composition of, 46 microscopy of, 112, 124, 125 Cayenne, composition of, 46 microscopy of, 114, 125 white, composition of, 46 microscopy of, 112, 124, 125 Peppermint extract, 201 Pericarp, 94, 98, 103 Perisperm, 96, 109, 112 Phosphates in baking powder, 78, 80 Phosphoric acid in liquors, 170 Photosynthesis, 122 Phytosterols, 3 Piperine, 56, 72, 114 Plumule, loi Polariscope, 128 Polarization of honey, 133 Karo syrup, 133 light, 85, 129 molasses, 133 sucrose, 130 Polenske number, 159 Poppyseed oil, 140 Pork, composition of, 35 Potassium sulphate in wine, 170 Potato starch, 89, 91, 93 Potatoes, composition of, 45 sweet, composition of, 45 Preservatives, 31, 36, 38, 177 in fruit products, 177 ice cream, 31 liquors, 170 milk, 20, 25 wines, 170 Preserves, 177 INDEX 249 Protein determination, 25, 30, 65, 72, 206, 208, 210 standard solutions, 70 in animal foods, i, 35 butter, 26, 27 cheese, 29, 30 cocoa products, 210 coffee, 206 eggs, 34, 35 fish, 34, 35 fruit products, 162 fruits, 45, 65 liquors, 170 meat, 34, 35 milk, 10, 25 mill products, 44, 65 nuts, 45, 65 pepper, 72 spices, 46, 72 tea, 208 vegetable foods, 2, 41, 44, 45, 46, 65, 72 vegetables, 45, 65 nature of, 63 Proteins, see Protein. Ptyalin, 75 Quevenne lactometer, 14 R Radicle, loi Rape oil, 140, 155 Rapic acid, 140 Raspberries, composition of, 45 Reagent list, 235 Refractive index, 3, 146 Refractometer, 146 Reichert-Meissl number, 157 Renard peanut oil test, 151 Resin cavities, 109 Rice, composition of, 44 Richmond milk scale, 25 Robin cochineal test, 138 Roese-Gottlieb fat method, 30 Rye, bran, composition of, 44 Rye, bran, microscopy of, 99, 124 flour, composition of, 44 microscopy of, 99, 124 microscopy of, 99 Saccharimeter, 1 28 Saccharine products, 127 analysis of, 128, 133, 135 literature of, 6 Saccharomyces, 78, 168, 169 Sachsse starch conversion method, 75 Salicylic acid, 36 Salmon, composition of, 35 Sample, care of, 49 drawing, 13, 46 preparing, 26, 48 Sampling, 13, 46 tube, 13, 47 Saponification number, 3, 155 Sarcolemma, 33 Saturated fatty acids, 139, 140 Scallops, composition of, 35 Schreiner colorimeter, 193 Scovell milk sampler, 13 Scutellum, 95, 102 Sesame oil, 140, 143, 151 test for, 151 Shad, composition of, 35 Short method for fat in cheese, 30 Sieve for samples, 48 Sitosterol, 3, 161 Slides, microscopic, 86 Sodium benzoate, 36, 178 chloride, 170 Solidifying point of fatty acids, 160 Solids, total, calculation, 25 determination, 15, 16 in fruit products, 164, 166 liquors, 174 milk, 15, 16 calculation, 25 saccharine products, 135 vinegar, 177 Soluble fatty acids, 160 Soxhlet fat extractor, 21, 22 250 INDEX Specific gravity determination, 14 of fats and oUs, 144 milk, 14, 25 Spermoderm, 96, 104, 105, 107, no, ill Spice extracts, 201 Spices, 2 analysis of, 43, 55, 59, 72 composition of, 46 ether extract of, 59 protein in, 72 water in, 55 Spongy parenchyma, 98, 104 Squibb burette, 67 Starch, 2, 3, 41, 74, 75. 88 bean, 89, 93 buckwheat, 104 cassava, 92, 93 chemical properties of, 74 cinnamon, 116 cocoa, 121 com, 90, 93, 124 curcuma, 89 determination, 75 ginger, 118, 125 grains, 88 aggregates of, 92, 93 form of, 90, 93 hilum of, 9I; 93 polarization crosses of, 92, 93 rings of, 91,93 size of, 92, 93 table of, 93 in baking powder, 78, 81 chocolate, 121, 209 flour, 75 vegetable products, 93 microscopic characters of, 88 nature of, 74, 88 oat, 90, 93 pea, 106 pepper, 114, 124 potato, 89, 91, 93 properties of, 74, 88 rye, 99 wheat, 89, 93, 98 Starches, microscopy of, 188, 124 Stearic acid, 139, 140 Stone cells, 112, 115, 119, 122 Strawberries, composition of, 45 Strippings, milk, 12 Suberin, 2, 59, 116 Sucrose, characters of, 127 constitution of, 127 in condensed milk, 30 fruit products, 162, 167 molasses, 133 sugar, 130 syrup, 133 vanilla extract, 196 inversion of, 127, 131 polarization of, 130 Sugar, analysis of, 130 invert, see Invert sugar, polarization of, 130 sucrose in, 130 Sugars, 2, 3, 33, 74, 127, 161, 167 in liquors, 1 70 Sulphates in baking powder, 78, 80 Sulphur dioxide, 36, 37, 38, 178 determination, 38 in fruit products, 178 meat, 37, 38 Sulphurous acid, see Sulphur dioxide. Sunflower oil, 140 Sweet potatoes, composition of, 45 Syrup, fruit, 136 colors in, 137, 138 Karo, 133 solids in, 135 sucrose in, 133 maple, 135 analysis of, 135 Table, alcohol from specific gravity, 226 dry substance from refractive index, 224 lactometer temperature corrections, 211 refractometer readings, 222 sugars from cuprous oxide, 213 temperature corrections for dry sub- stance from refractive index, 225 INDEX 251 Table, total solids from lactometer readings and fat, 212 Tables, calculation, 211 Tallow, 143 Tannin in tea, 208 wine, 170 Tartaric acid, 162 Tea, 2, 207 analysis of, 208 caffeine in, 207, 208 colors in, 207 composition of, 42, 207 facing of, 207 foreign leaves in, 208 microscopy of, 122 spent leaves in, 208 tannin in, 208 Test, baking, for flour, 77 Baudouin for sesame oil, 151 Bechi, for cotton seed oil, 151 bromination, for oils, 160 Crampton and Simon, for palm oil, 152 Dalican's titer, 160 for aluminum salts in baking powder, 80 beef stearin, 152 borax in milk, 25 boric acid in milk, 25 colors in butter, 152 fruit products, 137, 138 ice cream, 31 lemon extract, 200 tea, 207 \\'ine, 170 cotton seed oil, 150 coumarin, 189 facing of tea, 207 foreign leaves in tea, 208 formaldehyde in milk, 20 homogenized oil in ice cream, 31 palm oil in butter, 152 peanut oil, 152 phosphates in baking powder, 80 preservatives in fruit products, 177 ice cream, 31 liquors, 170 Test for preservatives in milk, 20, 25 wines, 170 sesame oil, 151 spent leaves in tea, 208 starch in baking powder, 80 vegetable products, 93 sulphates in baking powder, 80 thickeners in ice cream, 31 wood alcohol in liquors, 170 Halphen, for cotton seed oil, 150 Leach, for coumarin, 189 Maumene, 160 Patrick, for ice cream thickeners, 31 Renard, for peanut oil, 151 titer, 160 Theobromine, 3, 203 in cocoa products, 209, 210 Thickeners, ice cream, 31 Tintometer, Lo\abond, 189 Titer test, 160 Tomatoes, composition of, 45 Tonka beans, 181 Trout, composition of, 35 Tube cells, 98, 103 Turnips, composition of, 45 U Unsaponifiable matter of fats, 161 Unsaturated acids, 139, 140 Vanilla beans, 180 extract, 180, 181 acidity of, 196 adulteration of, 188 alcohol in, 196 ash of, 196 color value of, 189 composition of, 182 coumarin in, 184 normal lead number of, 191 practice material, 183 preparation of, 182 substitutes for, 183 vanillin in, 184 Vanillin, 4, 181 colorimetric method, 192 252 INDEX Vanillin, gravimetric method, 184 in vanilla beans, 180 extracts, 182, 184, 192 substitutes, 184, 192 Veal, composition of, 35 Vegetable foods, 2, 41 microscopy of, 83, 93 Vegetables, 2, 43, 45 analysis of, 43 composition of, 45 Vessels, 113, 118, 120 Villavecchia and Fabris sesame oil test, 151 Vinegar, 162 acidity of, 177 cider, 174 composition of, 176 distilled, 174 glucose, 17s malt, 174 manufacture of, 175 molasses, 175 solids in, 177 sugar, 17s wine, 174 Volatile fatty acids, 3, 31. ^57 W Wagner skim milk test bottle, 19 Walnuts, composition of, 45 Water determination, 34, 50, 52 in animal foods, i, 34, 35 butter, 26, 27 cheese, 29, 30 cocoa products, 210 coffee, 206 eggs, 34, 35 fish, 34, 35 fruit products, 162 fruits, 45 meat, 34, 35 milk, II, 15 mill products, 44, 50, 52 nuts, 45 saccharine products, 135 spices, 46, 55 Water in tea, 208 vegetable foods, 41, 44, 45, 46, 50. 52 vegetables, 45, 47 oven, 17 Watermelons, composition of, 45 Weighing bottle, 60 Westphal balance, 144 Whale oil, 161 Wheat bran, composition of, 44 microscopy of, 99, 124 flour, composition of, 44 microscopy of, 99, 1 24 starch in, 75, 99 microscopy of, 94, 1 24 starch, 89, 93, 98, 124 White fish, composition of, 35 pepper, composition of, 46 microscopy of, 112, 124, 125 Wine, 168 colors in, 1 70 composition of, 171 constituents of, 1 70 fermentation, 168 preservatives in, 170 Wintergreen extract, 200 Winton and Lott normal lead number method, 191 cream test bottle, 19 Wood alcohol, test for, 170 X Xanthine, 33 bases, i, 33, 34 Xylan, 77 Xylose, 77 Yeast, 78 plants, 73, 168, 169 Zein, 102 Zoosterols, i Zymase, 168