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Titles included in this collection are listed in the volumes published by the Comell University Press in the series The Literature of the Agricultural Sciences, 1991-1996, Wallace C. Olsen, series e^tor. THE MICROSCOPY OF VEGETABLE FOODS WITH SPECIAL REFERENCE TO THE DETECTION OF ADULTERATION AND THE DIAGNOSIS OF MIXTURES BY ANDREW L. WINTON, Ph.D. In Charge of the Analytical Laboratory of the Connecticut Agricultural Experiment Station Instructor in Proximate Organic Analysis in the Sheffield Scientific School of Yale University WITH THE COLLABORATION OF Dr. JOSEF MOELLER Professor of Pharmacology, and Head of the Pharmacological Institute . University of Graz WITH 589 ILLUSTRATIONS FIRST EDITION FIRST THOUSAND NEW YORK JOHN WILEY & SONS London: CHAPMAN & HALL, Limited 1906 Al W Copyright, iqo6 BY ANDREW L. WINTON Entered at Stationers' Hall ROBERT DFUMMOND, PRINTBR, NEW YORV PREFACE. The development of vegetable histology, both as a pure and an applied science, has been largely in the hands of continental investi- gators. A generation ago Sachs, De Bary, and other histologists labored on the purely scientific problems; since then Vogl, Moeller, TschircK, T. F. Hanausek, Oesterle, Planchon, ColKn, Hohnel, Mace, and other technical microscopists, without neglecting research problems, have developed microscopical methods for the diagnosis of foods, drugs, and fibers which rank with chemical methods in practical importance. The extensive Uterature in the German and French languages on the microscopy of foods includes several comprehensive works devoted exclusively to the subject, a still greater number covering either the wider range of foods and drugs or limited to special fields, such as cereal products and cattle foods, as well as numerous papers in botanical, phar- maceutical, and technical journals. In Enghsh the dearth of literature on a subject of such scientific and technical importance is noteworthy. No single work devoted exclu- sively to food microscopy has hitherto appeared, although Hassall, Leach, and some other analysts, have described microscopical as well as chem- ical methods, and other authors, notably Greenish, Kraemer, and Jel- lifle, have treated on the microscopy of both foods and drugs. The present work is designed for the use of the food analyst, the agricultural chemist, the pharmacist, and others engaged in the exami- nation of foods, as well as the physician who may be called upon to identify vegetable substances in stomach contents and fasces. It aims to be comprehensive, covering the important vegetable foods for man and cattle, and at the same time sufficiently concise for ready reference. The idea that a scientific grounding is essential for practical work is paramount throughout. Only by a systematic study of each product IV PREF/ICE. from the morphological and physiological standpoint can one hope to develop keen observation and secure lasting impressions. The work is closely affiliated with the second edition of Moeller's "Mikroskopie der Nahrungs- und Genussmittel," which appeared a few months since with the collaboration of the writer. The descriptions of the individual leaves, flowers, barks, roots, and edible fungi, with few exceptions, are translations of Professor Moeller's text, and no less than 350 cuts are also his. It is with the deepest gratitude that the writer acknowledges this generous cooperation of his honored teacher and friend. Had it not been for Professor Moeller's unselfish aid, the writer would never have undertaken investigations in this field, much less a comprehensive treatise. Valuable cuts have been borrowed from the following well-known authors: Berg, Collin and Perrot, Frank, Gilg, Hager, Halstrom, T. F. Hanausek, Hartig, HassaU, Kny, Leach, Luerssen, Malfatti, A. Meyer, Mez, R. Miiller, Nees, Nobbe, Planchon and Collin, Sachs, Schimper, Schumann, Tschirch, Tschirch and Oesterle, Tulasne, Villiers and Col- lin, Vogl, Warburg, and Wittmack and Buchwald. Numerous cuts, made from the writer's drawings for publications of the Connecticut Agricultural Experiment Station, are reproduced with the kind permission of that institution. Acknowledgment for the use of cuts is also due the following pubhshers: Julius Springer, Berlin (publisher of Moeller's Mikroskopie); The Clarendon Press, Oxford; Octave Doin, Paris; Wm. Engelmann, Leipsig; Ferdinand Enke, Stuttgart; Gustav Fischer, Jena; Carl Gerold's Sohn, Vienna; H. Haessell, Leipsig; Alfred Holder, Vienna; A. Joanin & Cie., Paris; Longmans, Green, & Co., London; Paul Parey, Berlin; Chr. Herm. Tauchnitz, Leipsig; Urban & Schwarz- enberg, Berlin and Vienna; J. J. Weber, Leipsig; Weidmannsche Buch- handlung, Berlin. Permission to reproduce Fig. 16 was kindly granted by Mr. E. Goodwin Clayton, F.I.C., F.C.S., consulting chemist, 32 Holbom Viaduct, London, England. The larger part of Professor Moeller's and the writer's drawings were reproduced on wood by F. X. Matolony of Vienna. In the preparation of the text the works of the leading authors have been consulted, and credit has frequently been given for important dis- coveries, although so far as possible the writer has based his descriptions on his own observations. The descriptions of cucurbitaceous fruits and three excellent cuts illustrating the structure of the pumpkin were con- tributed by Miss Kate G. Barber. PREFACE. V The bibliographies throughout the work and the glossary are largely the work of my wife, who has devoted much time and thought to other details. Professor Moeller's analytical key to commercial starches will be found a reliable guide in diagnosis. It is hoped the writer's keys to cereals, cruciferous seeds, umbelliferous fruits, legumes, and spices will also prove of value, although they are not universally applicable since many materials lack certain histological elements present in the original prod- uct. The indulgence of the reader is asked for omissions of which the writer is painfully aware, and for errors which doubtless will be detected. New Haven, Conn., November i, 1905. CONTENTS. PART I. PRELIMINARY: EQUIPMENT, METHODS, AND GENERAL PRINCIPLES. PAGB INTRODUCTION 3 APPARATUS 6 REAGENTS 8 COLLECTIONS ii PREPARATION OF MATERIALS FOR EXAMINATION 12 Mechanicai, Preparation 12 Treatment with Reagents 15 THE PRINCIPAL HISTOLOGICAL ELEMENTS 20 Tissues , 20 Ceu,-contents 23 MORPHOLOGY OF ORGANS 28 The Leaf 28 The Flower 30 The Fruit 33 Pericarp 33 Seed ■ 35 The Stem 38 Bark 40 Wood 41 The Root. 44 PART II. GRAIN: ITS PRODUCTS AND IMPURITIES. GRAIN ■ 49 Flour and Meal 49 Impurities and Adulterants .' 49 Methods of Examination 52 vii viii CONTENTS. PAGB Bread 56 Cattle Foods 57 Methods of Examination 59 Cereals (Graminea) 60 Microscopic Characters 62 Analytical Keys 63 Wheat (Triticum) 65 Spelt (Triticum, sativum var. Speltd) 73 Emmer {Triticum. sativum var. dicoccum) 75 One-grained Wheat (Triticum monococcum) '(> Rye (Secale cereale) 77 Barley (Hordeum sativum) 80 Maize (Zea Mays) 86 Broom Com (Andropogon Sorghum var. technicus) 97 Sugar Sorghum (Andropogon Sorghum var. saccharatus) 103 Kaffir Corn (Andropogon Sorghum) 104 Durrha (Andropogon Sorghum var. durra) 104 Rice (Oryza sativa) 105 Oats (Avena sativa) iii Common Millet (Panicum miliaceum) 116 German Millet (Setaria Italica=S. panis) 118 Green Foxtail (Setaria viridis = Chmtochloa viridis) 118 Yellow Foxtail (Setaria glauca = Chmtochloa glauca) 1 24 Darnel (Lolium temulentum) 125 Chess (Bromus secalinus) 1 30 Buckwheats (Polygonacea) 132 Common Buckwheat (Fagopyrum esculentum) 1 32 Tartary Buckwheat (Fagopyrum Tartaricum) 138 Black Bindweed (Polygonum Convolvulus) 138 Other Polygonaceous Seeds 144 WEED SEEDS 145 Screenings 145 European 145 American 1 46 Analyses 147 Methods of Examination 148 CaryophyllacEOUs Seeds (Caryophyllacece) 148 Cockle (Agrostemma Githago) i ^S Cow Herb (Vaccaria parviflora = Saponaria Vaccaria) 151 Soapwort (Saponaria officinalis) 151 Spurrey (Spergula arvensis) 152 Ranunculaceous Seeds (Ranuncutacece) 1^2 Buttercup Fruit (Ranunculus arvensis) 153 Adonis Fruit (Adonis eestivalis, A. Flammea)' j^. Larkspur Seed (Delphinium Consolida) 1^5 Louse Seed (Delphinium Staphysagria) ij^ Black Caraway (Nigella arvensis) 1 56 Miscellaneous Weed Seeds ,56 Cow Wheat (Melampyrum arvense) 1^6 Bindweed (Convolvulus arvensis) j^y CONTENTS. IX PAGE Wild Carrot (Daucus Caroia) 158 Hollow Seed {Bijora radians) 159 Cornflower (Centaurea Cyanus) 160 Cleavers {Galium) 161 Plantain (Plantago major, P. lanceolata) 163 FUNGUS IMPURITIES 164 Ergot {Claviceps purpurea) 1 64 Smuts {UsUlago, Tilletia, etc.) 165 PART III. OIL SEEDS AND OIL CAKES. OIL SEEDS .■ 169 Oil-seed Products i6g Methods of Examination 1 70 Cruciferous SEEds {Crucijem) 172 Microscopic Characters 1 73 Analytical Key 174 White Mustard (Sinapis alba) : 1 76 Black Mustard (Brassica nigra) 1 80 Sarepta Mustard (Brassica Besseriarm) 1 83 Charlock (Brassica Sinapistrum= Sinapis arvensis) 184 Common Rape (Brassica Napus) 185 German Rape (Brassica Rapa) 187 Indian Colza (Brassica campestris var. Sarsori) 187 Brown Indian Rape (Brassica Napus var. dichotoma) 188 Indian Mustard (Brassica juncea) 188 Palai Rape (Brassica rugosa) 188 Dissected Mustard (Brassica dissecta) 1 89 Eruca (Eruca saliva) 1 89 False Flax (Camelina saliva) 189 Hedge Mustard (Sisymbrium officinale, S. Sophia, etc.) 191 Shepherd's Purse (Capsella Bursa-Pasloris) 191 Wild Peppergrass (Lepidium campestre, L. sativum) 192 Field Pennycress (Thlaspi arvense) 1 92 Treacle Mustard (Erysimum orientale) 192 Wild Radish (Rapkanus Raphanistrum) 193 Winter Cress (Barbarea vulgaris) 193 Composite Oil Fruits (CompositcB) '. 193 Sunflower (Helianlhus annuus) 194 Madia Seed (Madia saliva) 197 Niger Seed (Guizotia Abyssinica = G. oleifera). 2CO MiscELi-ANEous Oil Seeds 202 Linseed (Linum usitatissimum) 202 Cottonseed (Gossypium herbaceum) 205 Kapok Seed (Ceibo pentandra = Eriodendron anfracluosum) 211 CONTENTS. PAGE Hemp Seed [Cannabis saliva) 212 Sesame Seed (Sesamutn Indicum) 217 Castor Bean (Ridnus communis) 220 Candlenut {Aleurites triloba = A. Moluccana) 222 Poppy Seed {Papaver somnijerum) 223 Olive (Olea Europea) 226 PART IV. LEGUMES. LEGUMES (Leguminosm) 233 Microscopic Characters 233 Analytical Key 235 Common Bean {Phaseolus vulgaris) 238 Spanish Bean {Phaseolus multiflorus) 240 Adzuki Bean {Phaseolus Mungo, var. glaber) 241 Lima Bean {Pliaseolus lunatus) 241 Pea {Pisum arvense, P. sativum) 242 Lentil {Lens esculenta — Ervum Lens) 245 China Bean {Vigna Catjang= V. Sinensis = Dolichos Sinensis) 247 Soy Bean {Glycine hispida =Soja hispida) 248 Egyptian Bean {Dolichos Lablab = Lablab vulgaris) 249 Horse Bean {Faba vulgaris = Vicia Faba) 250 Spring Vetch {Vicia saliva) 251 Winter Vetch {Vicia villosa) 252 Hairy Vetch {Vicia hirsute) 252 Yellow Lupine {Lupinus luteus) 253 White Lupine {Lupinus albus) 255 Blue Lupine {Lupinus angtistifolius) 255 Chick Pea {Cicer arietinum) 256 Soudan Coffee {Parkia Africana, P. Roxburgii) 257 Jack Bean {Canavalia ensiformis, C. obtusifolia) 258 Fenugreek {Trigonella Fcenum-Grmcum) 259 Coffee Cassia {Cassia occidentalis) 262 Astragalus {Astragalus bcsticus) 264 Lucerne {Medicago saliva) 265 Peanut {Arachis hypogcza) 266 Tonka Bean {Coumarouna odorata = Dipteryx odorata, etc.) 273 Carob Bean {Ceratonia Siliqua).' 2yc CONTENTS. XI PART V. NUTS. PAGE NUTS 281 Palm Fruits (Palmce) 281 Cocoanut (Cocos micifera) 281 Palm-nut {Elceis Guineensis) 290 Wax-palm (Corypha cerijera = Copernica cerifera) 292 Ivory-nut {Phytelephas macrocarpa, etc.) 293 Polynesian Ivory-nut (Coclococcus) 295 Walnuts (Juglandacece) 295 European Walnut (Juglans regia) 295 Black Walnut (Juglans nigra) : 298 Butternut {Juglans cinerea) 298 Pecan Nut {Carya olivcejormis) 298 Hickory -nut (Carya alba) 299 Cup Nuts {CupulijertB) 299 Chestnut (Castanea saliva, etc.) 299 Acorn {Quercus) 302 Beech-nut (Fagus syhatica, F. jerruginea) 307 Hazelnut (Corylits) 309 Miscellaneous Nuts 312 Brazil-nut (Bertholletia excelsa) 312 Pistachio-nut {Pistacia vera) ^ 315 Pine-nut {Pinus Pinea, P. Cembra) 316 PART VI. FRUIT AND FRUIT PRODUCTS. FRUIT 319 Fruit Products 319 Adulterants 319 Methods of Examination 320 Rosaceous Fruits (Rosacece) 323 Apple (Pyrus Malus) 323 Pear (Pyrus communis) 328 Quince (Cydonia vulgaris = Pyrus Cydonia) 331 Almond {Prunus amygdalus) 333 Peach {Prunus Persica) 337 Apricot {Prunus Armeniaca) 339 Plum {Prunus domesiica, P. tri flora) 3^.0 Cherry {Prunus avium, P. cerasus) 341 Rose Fruit {Rosa canina) 342 Strawberry {Fragaria) 343 Xll CONTENTS. PAGE Red Raspberry {Rubus Id/zus, etc.) 349 Black Raspberry {Rubus occidentalis) 354 Blackberry {Rubus jruiicosus, etc.) 354 Saxifragaceous Fruits (Saxifragacece) 357 Red Currant (Rites rubrum) 357 Black Currant (Ribes nigrum) 362 Gooseberry {Ribes Grossularia, etc.) 363 Ericaceous Fruits {Ericaceoe) 366 Cranberry {Vaccinium macrocarpon, etc.) 366 Blueberry {Vaccinium Myrtillus, etc.) 370 Huckleberry {Gaylussada resinosa) 373 Citrus Fruits {Rutacece) 376 Orange {Citrus Aurantium) 376 Lemon {Citrus medica, var. Limon) 381 Citron {Citrus medica, vslT. genuina) 381 Miscellaneous Fruits 382 Grape {Vitis vinifera) 382 Fig {Ficus Carica) 386 Date {Phcenix dactylifera) 390 Banana {Musa sapientum) 393 Pineapple {Ananassa sativa) 395 PART VII. VEGETABLES. VEGETABLES 401 Cucurbit Fruits {Cucurbitaces) 401 Pumpkin {Cucurbita Pepo) .02 Squash {Cucurbita maxima) . q5 Cucumber {Cucumis sativus) .06 Muskmelon {Cucumis Melo) .q- Watermelon {CitruUus vulgaris) -og Solanaceous Fruits (Solanacetz) . ,q Tomato {Solanum Lycopersicum — Lycopersicum esculentum) jio Tubers and Roots , , , Potato {Solatium tuberosum) .j. Japanese Potato {Stachys Sieboldii) . j ,. Jerusalem Artichoke {Helianthus tuberosus) . jg Beet {Beta vulgaris) _ Carrot {Daucus Carota) . jg Turnip {Drassica Rapa) . j„ Fungi 4,^ Truffles {Tuber) ^^^ Morels {Morchella, Cymttra, Helvella) -22 Mushrooms {Psalliota, Boletus) ■ .j. CONTENTS. XIU PART VIII. ALKALOIDAL PRODUCTS AND THEIR SUBSTITUTES. PAOB ALKALOIDAL PRODUCTS 427 Coffee {Cofjea Arabica) 427 Liberian Coffee (Coffea Liberica) 438 Chicory (Chicorium Intybus) 438 Dandelion {Leontodon Taraxacum) 440 Cocoa Bean (Theobroma Cacao) 442 Guarana {Pauttinia sorbilis) 451 Kola Nut {Cola acuminata) 452 Tea {Camellia Tliea) 452 Gromwell Leaves {Lithospermum officinale) 458 Willow Herb Leaves {Epilobium angustijolium = Chamaenerium angusii- joliuni) 459 Willow Leaves {Salix) 461 Ash Leaves {Fraxinus sp.) 462 Rowan Leaves {Sorbus Aucuparia = Pyrus Aucuparia) 463 Mulberry Leaves {Morus alba, M. nigra) 464 Coffee Leaves {Coffea Arabica) 466 Camellia Leaves {Camellia Japonica) 467 Cherry Leaves {Prunus avium) 468 Sloe Leaves {Prunus spinosa) 469 Rose Leaves {Rosa canina, etc.) 470 Strawberry Leaves {Fragaria vesca) 47 1 Meadowsweet Leaves {Spiraea Ulmaria) 473 Wistaria Leaves {Wistaria Sinensis = Kraunkia floribunda) 475 Hydrangea Leaves {Hydrangea Hortensia) 476 Maple Leaves {Acer Negundo =Negundo fraxinilolium) 477 Oak Leaves {Quercus pedunculata, Q. sessiliflora) 477 Akebia Leaves {Akebia quinata) 478 Blueberry Leaves {Vaccimum Myrtillus) 480 Caucasian Tea {Vaccinium Arctostaphylos) . , 481 Other Tea Substitutes 483 Mate {Ilex Paraguariensis) 483 Coca {Erythroxylon Coca) 485 Tobacco {Nicotiana Tabacum, N. rustica) 486 xii CONTENTS. PAGB Red Raspberry (Ruhus Idtmis, etc.) 349 Black Raspberry (Rubus occidentalis) 354 Blackberry {Rubus fruticosus, etc.) 354 Saxifragaceous Fruits (JSaxifragacea) 357 Red Currant (Ribes rubrum) 357 Black Currant (Ribes nigrum) 3^2 Gooseberry (Ribes Grossularia, etc.) 3^3 Ericaceous Fruits (Ericacece) 3^6 Cranberry (Vaccinium macrocarpon, etc.) 3^6 Blueberry (yaccinium Myriillus, etc.) 37° Huckleberry (Gaylussacia resinosa) 373 Citrus Fruits {RulacecB) 376 Orange {Citrus Aurantium) 37^ Lemon (Citrus medica, var. Limon) 381 Citron (Citrus medica, var. genuina) 381 Miscellaneous Fruits 382 Grape (Vitis vinifera) 382 Fig (Ficus Carica) 386 Date (Phoenix dactylifera) 390 Banana (Musa sapientum) 393 Pineapple (Ananassa saiiva) 395 PART VII. VEGETABLES. VEGETABLES 401 Cucurbit Fruits (Cucurbitacete) 401 Pumpkin (Cu^urbita Pepo) 402 Squash (Cucurbita maxima) 406 Cucumber (Cucumis sativus) 406 Muskmelon (Cucumis Melo) 407 Watermelon (Citrullus vulgaris) 408 Solanaceous Fruits (Solanacece) 410 Tomato (Solanum Lycopersicum=Lycopersicum esculentum) 410 Tubers and Roots 414 Potato (Solanum tuberosum) 414 Japanese Potato (Stachys Sieboldii) 415 Jerusalem Artichoke (Helianthus tuberosus) 416 Beet (Beta vulgaris) 417 Carrot (Daucus Caroia) 418 Turnip (Brassica Rapa) 419 Fungi 419 Truffles (Tuber) 420 Morels (Morchella, Cymitra, Helvetia) 422 Mushrooms (Psalliota, Boletus) 423 CONTENTS. xm PART VIII. ALKALOIDAL PRODUCTS AND THEIR SUBSTITUTES. PAOB ALKALOIDAL PRODUCTS 427 Coffee (Coffea Arabica) 427 Liberian Coffee {Coffea Liberica) 438 Chicory {Chicorium Intybus) 438 Dandelion {Leontodon Taraxacum) 440 Cocoa Bean (Theobroma Cacao) 442 Guarana {Paullinia sorbilis) 451 Kola Nut {Cola acuminata) 452 Tea {Camellia Tliea) 452 Gromwell Leaves {Lithospermum officinale) 458 Willow Herb Leaves {Epilobium angustijolium = Chamaenerium angusti- jolium) 459 Willow Leaves {Salix) 461 Ash Leaves {Fraxinus sp.) 462 Rowan Leaves {Sorbus Aucuparia = Pyrus Aucuparia) 463 Mulberry Leaves {Morus alba, M. nigra) 464 Coffee Leaves {Coffea Arabica) 466 Camellia Leaves {Camellia Japonica) 467 Cherry Leaves {Prunus avium) 468 Sloe Leaves {Prunus spinosa) 469 Rose Leaves {Rosa canina, etc.) 470 Strawberry Leaves {Fragaria vesca) 47 1 Meadowsweet Leaves {Spircea Ulmaria) 473 Wistaria Leaves {Wistaria Sinensis = Kraunhia floribunda) 475 Hydrangea Leaves {Hydrangea Hortensia) 476 Maple Leaves {Acer Negundo =Negundo jraxinilolium) 477 Oak Leaves {Quercus pedunculata, Q. sessilifiora) 477 Akebia Leaves {Akebia quinata) 478 Blueberry Leaves {Vaccinium Myrtillus) 480 Caucasian Tea {Vaccinium Arclostaphylos) . 481 Other Tea Substitutes 483 Mate {Ilex Paraguariensis) 483 Coca {Erythroxylon Coca) 485 Tobacco {Nicotiana Tabacum, N. rustica) 486 xiv CONTENTS. PART IX. SPICES AND CONDIMENTS. PAGB SPICES AND CONDIMENTS 493 Impurities 493 Adulterants 494 Methods of Examination 496 Analytical Key 49^ Condimental Cattle and Poultry Foods 499 Methods of Examination 500 PiPERACEOus Fruits {Piperacex) 502 Pepper {Piper nigrum) 502 Long Pepper {Piper officinarum, P. longum) 511 Cubebs {Piper Cubeba) 513 SoLANACEOus Fruits {Solanacece) 515 Paprika {Capsicum) 515 Cayenne Pepper {Capsicum fastigiatum, etc.) 523 Myrtaceous Fruits {Myrtacece) 526 Allspice {Pimenta officinalis, etc.) 526 Nutmegs and Mace {Myristicacem) 531 True Nutmeg and Mace {Myristica jragrans) 531 Macassar Nutmeg and Mace {Myristica argentea) 540 Bombay Mace {Myristica Malabarica) 540 Cardamoms {Zingiberacece) 542 Malabar Cardamom {Elettaria Cardamomum, Amomum Cardamomum, etc.) 542 Ceylon Cardamom {Elettaria Cardamomum) 547 Umbelliferous Fruits {Umbellifer(E) 545 Comparative Histology of Umbelliferous Fruits 550 Analytical Key 551 Fennel {Fceniculum capillaceum) 552 Caraway {Carum Carvi) '. j^j Anise {Pimpinella Anisum) ccg Cumin {Cuminum Cyminum) ego Coriander {Coriandrum sativum) C62 Dill {Anethum graveolens) C64 Celery Seed {Apium graveolens) -gc Miscellaneous Fruits and Seeds -66 Star-anise {lllicium verum) -gg Shikimi {lllicium religiosum) ,72 Vanilla {Vanilla planifolia) ,,, Vanillon {Vanilla pompona) c^g Bayberry {Laurus nobilis) --„ Juniper Berry {Juniperus communis) 1-82 Barks -gc Cassia {Cinnamomum) -g, Cassia Buds {Cinnamomum Cassia) -gj Ceylon Cinnamon {Cinnamomum Ceylonicum) cn^ CONTENTS XV PAGE Clove Bark {Dicypellium caryophyllatum) 594 Canella Bark (Canella alba) 597 Rhizomes 599 Ginger {Zingiber officinale, etc.) * 599 Turmeric {Curcuma longa) 602 Zedoary {Curcuma Zedoarid) 605 Galangal {Alpinia ofjicinarum, A. calcarata) 606 Sweet Flag {Acorus Calamus) 608 Leaves 610 Sage {Salvia officinalis) 610 Marjoram {Origanum Majorana) 612 Savory {Satureja hortensis) 613 Thyme {Thymus vulgaris) 615 Hyssop {Hyssopus officinalis) 615 Bay-leaf {Laurus nobilis) 616 Tarragon {Artemisia Dracunculus) 617 Wormwood {Artemisia vulgaris) 619 Sorrel {Rumex scutatus) 62 1 Flowers 622 Saffron {Crocus saiivus) 623 Marigold Flowers {Calendula officinalis) 627 Safflower {Carthamus tinctorius) 629 Cape Saffron {Lyperia crocea) 631 South African Saffron {Tritonia aurea = Crocosma aurea—Babiana aurea). 632 Maize Silk {Zea Mays) 632 Cloves {Eugenia caryophyllata = J ambosa Caryophylltis = Caryophyllus aromaticus) 632 Clove Stems 636 Clove Fruit 637 Capers {Capparis spinosa) 639 PART X. COMMERCIAL STARCHES. COMMERCIAL STARCHES 643 Analytical Key 649 Maize Starch {Zea Mays) 651 Rice Starch {Oryza saiiva) 652 Wheat Starch {Triticum sativum) 653 Buckwheat Starch {Fagopyrum esculentum) 654 Leguminous Starches {Leguminosce) 655 Chestnut Starch {Casianea vesca) 656 Horse-chestnut Starch {Msculus Hippocastanum) 657 Bean-tree Starch {Castanospermum Australe) 658 Banana Starch {Mu^a) 658 XVI CONTENTS. PAGS Bread-fruit Starch (Ariocarptis incisa) 659 Potato Starch (Solatium tuberosum) 659 Maranta Starch or West India Arrowroot {Maranta arundinacea) 660 Curcuma Starch or East India Arrowroot (Curcuma) 662 Canna Starch or Queensland Arrowroot (Canna) 662 Yam Starch or Guiana Arrowroot (Dioscorea) 663 Cassava Starch (Manihot utilisHma, M. aipi) 664 Sweet-potato Starch or Brazilian Arrowroot (Batatas edulis=IponuBa Batatas) 665 Arum Starch or Portland Arrowroot (Arum) 666 Tacca Starch or Tahiti Arrowroot (Tacca pinnatifida) 667 Sago (Metroxylon, Sagus, etc.) 667 Miscellaneous Starches 669 GENERAL BIBLIOGRAPHY 671 GLOSSARY 675 INDEX 685 PART I. PRELIMINARY: EQUIPMENT, METHODS AND GENERAL PRINCIPLES. THE MICROSCOPY OF VEGETABLE FOODS. INTRODUCTION. The Microscopy of Vegetable Foods is an applied analytical science having for its purpose the identification of food products of vege- table origin by the microscopic structure and microchemical reactions of their tissues and cell-contents. It is a branch of Analytical Vegetable Histology, other important branches being the Microscopy of Drugs, or Microscopic Pharmacognosy, and the Microscopy of Fibers. Preliminary Study. As the microscopy of foods, like the allied branches of analytical histology, is a department of applied botany, it cannot be properly taken up until after a course of instruction in the parent science, especially that part relating to the histology or microscopic anatomy of phanerogamic plants. To omit this is as irrational as to undertake the study of analytical chemistry v^rithout previous knowledge of general chemistry. This training in botany need not, however, be more than is given in a good high-school course with practical histological work, although a sup- plementary course in the histology of phanerogams is highly desirable. The student should begin his work in food microscopy with a sys- tematic study of the most important seeds, fruits, leaves, flowers, roots, and barks used as foods or food adulterants. This work should include: (i) the macroscopic anatomy; (2) the histology as studied in transverse (less often longitudinal or tangential) sections ; (3) the histology as studied in surface preparations of the successive layers obtained by scraping or stripping; and (4) the microscopic characters of the powdered, pulped, or macerated material. Macroscopic preparations show the general nature and relative size of the parts; cross-sections, the number of layers, order of arrangement, and certain details of structure; surface mounts, the details of cell structure most useful in practical work; and mounts of the powdered material, much that is learned from surface mounts and in 3 4 PREUMINy4RY. addition the characters of the isolated cell-elements and cell-contents. The student who has not the time, apparatus, or technique for cutting careful sections can use permanent mounts of a collection, or can even depend on illustrations of such sections, but he should prepare his own mounts for the study of each material in surface view or powder form. After this general work, which is analogous to the study of the reac- tions of the several bases and acids in his course in analytical chemistry, the student is prepared to undertake the diagnosis of mixtures. In this work he will find that of some materials, such, for example, as ground coffee, he can pick out fragments large enough for cutting sections, or preparing surface mounts by scraping, but as a rule he must depend entirely on the microscopic appearance of the powder. His knowledge gained by his study of sections and surface mounts of standard material will, however, be invaluable to him in interpreting the results of his exami- nations of powders. The object of this book is to aid both the student and the practical worker, assuming that both are familiar with the general principles of elementary botany, vegetable histology, and microtechnique, or at least are in a position to use inteUigently reference works on these subjects. Relation to Chemical Analysis. Although the work of microscopic examination is distinctly botanical, its chief value is in conjunction with chemical analysis, and for this reason is more often undertaken by the analyst with a moderate knowledge of vegetable histology than by the professional botanist. Only in large institutions can the work be divided among specialists. Both analytical chemistry and analytical histology, although widely unhke in their processes, are used in solving problems relating to the nature or purity of powdered foods, drugs, and other products of vegetable origin. Sometimes one line of investigation alone is useful, sometimes the other, but often each throws some light on the problem, thus furnishing an indisputable chain of evidence. Analytical chemistry determines the amount of fiber, starch, protein, oil, etc. ; analytical histology, the shape, size, reactions, and other char- acteristics of the cells and cell-contents. Analytical chemistry usually stops with the mere determination of the amount of chemical constituents • analytical histology goes further, and names the seeds, roots, barks, or other vegetable products from which the material was prepared. Ana- lytical chemistry answers a question in scientific terms ; analytical histology in terms which all can understand. INTRODUCTION. 5 In many cases a satisfactory idea of a material is gained only by fol- lowing out both lines of investigation. By chemical analysis we learn the percentage of protein, fiber, starch, etc., but not the ingredients from wliich they were derived; by microscopic analysis we learn the ingredients, but gain little idea of their proportion; but given the results of botli analyses, we may often calculate approximately the percentage of the different materials present. If, for example, we find in ground cloves 5 per cent instead of 15 per cent of essential oil, and 40 per cent instead of 8 per cent of fiber, we know it is not pure cloves ; if we find under the microscope a large amount of stone cells and other tissues of the cocoanut shell, we learn the adulterant. Knowing all this, and knowing the average percentage of volatile oil in cloves and of fiber in both cloves and cocoanut shells, we have the data for calculating roughly the percentage of each in the mixture. Mineral salts and other inorganic constituents of a mixture are iden- tified by chemical or microchemical tests, and the amounts present deter- mined by chemical methods. BIBLIOGRAPHY. 1 Elementary Botany. Bergen: The Foundations of Botany. Boston, 1903. Bessey: Botany for High Schools and Colleges. New York, 1880. Leavitt: Outlines of Botany. New York. Structural Botany. Gray: Structural Botany. New York, 1880. Vegetable Histology. See p. 25. Microscopy oj Drugs. Greenish: Foods and Drugs. London, 1903. Jelliffe: Introduction to Pharmacognosy. Philadelphia, 1904. Kraemer: a Course in Botany and Pharmacognosy. Philadelphia, 1902. Microscopy oj Fibers. Mathews: The Textile Fibers. New York, 1904. Chemistry oj Foods. Battershall: Food Adulteration and its Detection. New York, 1887. Bell: The Chemistry of Foods. London, 1881. Blyth: Foods, their Composition and Analysis. London, 1903. Hassall: Food, its Adulteration and the Methods for their Detection. London, 1876. Leach: Food Inspection and Analysis. New York, 1904. Leffmann and Beam : Select Methods of Food Analysis. Philadelphia, 1905. U. S. Dept. Agr., Bur. Chemistry, Bulletins 13, 46, and 65. ' AVorks in English. APPARATUS. It is beyond the province of this work to describe the construction of the microscope and microscopic apparatus, or give instructions for their care and use. Those who desire information of this nature are referred to the works named on p. 19 and the pamphlets issued by the leading makers of instruments. The list of apparatus which follows is designed merely as a guide for the purchaser. Essential Apparatus. The apparatus described under this head is essential for the most elcmentan,- work in food microscopy; on the other hand, it is sufficient for verifying nearly all the descriptions in this volume, and for undertaking most of the problems encountered in practical work. Compound Microscope. The stand should be of the Continental type, and should be provided with two objectives, a double nose-piece, two eye-pieces, an eye-piece micrometer, and a substage diaphragm. A satisfactory range in magnification is secured by f and | objectives and I- and 2-inch eye-pieces, of English and American makers, or Nos. 2 and 6 objectives and II and IV eye-pieces of Continental makers. A simple form of eye-piece micrometer is suited for our purpose. It may be calibrated by means of a stage micrometer. The double nose-piece, enabling the worker instantly to change from one objective to the other, is an inexpensive convenience that adds so much to the utility of the instrument that it may be regarded as a necessity. For ordinary work the only substage attachments needed are the mirror and a simple diaphragm, but the substage should be of such a construction as to permit the introduction of a substage condenser and an iris diaphragm. Simple Microscope. A pocket lens will answer the purpose, but an instrument with a stage and adjustable arm for the lenses is much more convenient. Turn-table with centering pins for ringing permanent mounts. Section Razor. This should be plano-concave and have a keen APP/IRATUS. 7 thin edge for cutting soft tissues. Another razor with a stronger edge is useful for cutting hard materials. Hone. Strop. Dissecling-needle Handles with interchangeable needles. Scalpel. Forceps with fine points. Slides of the usual size (3X1 inch) may be obtained either of thick or thin glass, as prefer'-ed. Cover-glasses. No. 2 round cover-glasses J inch in diameter are recommended for both temporary and permanent mounts. Reagent Bottles with stopper pipettes ground into the neck. Watch-glasses. Supplementary Apparatus. The following accessories, although not essential for ordinary work, should be in every well-appointed microscopi- cal laboratory. A Substage Condenser with an iris diaphragm attached is valuable in securing sufficient illumination on dark days. Polarizing Apparatus.^ This apparatus is useful chiefly in the exami- nation of starch grains, crystals, and thickened cell-walls. It consists of two Nicol prisms, one (the polarizer) mounted in the substage, the other (the analyzer) in the tube or above the eye-piece. Selenite plates for use with the polarizing apparatus may be mounted either in a revolving disk in the substage, or in a metal shp for use on the stage under the object-slide. A Mechanical Stage is of service in examining systematically every portion of a mount. A detachable form is recommended, as there are many times when this attachment is a hindrance rather than a convenience. Microtome. This instrument is of value in preparing uniformly thin sections, particularly of soft tissues. In preparing a series of sections it is invaluable. It is, however, an instrument for special investigation, and not for practical food examination. Parafjine Bath. For use in paraffine embedding. Camera Lucida. Useful in making drawings. Photomicro graphic Apparatus. This is especially useful in preparing exhibits for court cases. ' A convenient micropolariscope, arranged for instantly changing from plain to polarized light and vice versa, has been described by the writer. Jour. Apjil. Micros. 1899, 1, SI. REAGENTS. The following reagents comprise all that are needed for practical work. Others which are useful in special investigations are described in Strasburger's and Zimmerman's works. (See Bibhography, p. 19.) Acetic Acid. Glacial or 99 per cent acetic acid diluted with 2 parts of water. Alcohol. In dehydrating preparations for mounting in xylol balsam, absolute alcohol is used, but for preserving, hardening, and most other purposes ordinary 95 per cent alcohol meets every requirement. Alcanna Tincture. Macerate 20 grams of alkanet root for several days with 100 cc. of water. Dilute with an equal volume of water as used. Ammonia Water. The concentrated solution containing about 30 per cent of ammonia gas is used in making Schweitzer's reagent and for some other purposes. For the turmeric test the concentrated solution should be diluted with 10 parts of water. Canada Balsam in Xylol. The solution prepared ready for use may be obtained of all dealers in microscopic supplies. Chloral Hydrate Solution. Dissolve 8 parts of chloral hydrate in 5 parts of water. Chloroform. Chlorzinc Iodine Solution. Treat an excess of zinc with hydrochloric acid, evaporate to a specific gravity of 1.8, and filter through asbestos. As needed, saturate a small portion of the sirupy Hquid first with potas- sium iodide and finally with iodine. The solution may also be prepared by dissolving 30 grams of zinc chloride, 5 grams of potassium iodide, and 0.89 gram of iodine in 14 cc. of water. The solution should be freshly prepared, and kept in a dark place. Ether. Ferric Chloride. Dissolve i part of the salt in 100 parts of water. Fehling Solution. I. Dissolve 173 grams of crystallized Rochclle salts and 125 grams of caustic potash in water and make up to 500 cc. II. Dissolve 34.64 grams of crystallized copper sulphate in water and make up to 500 cc. Mix equal parts of I and II as needed. RE/t GENTS. 9 Glycerine. For use as a mounting medium, dilute with an equal volume of water. Glycerine Jelly (Kaiser's). Soak i part of finest French gelatine 2 hours in 6 parts of distilled water. Add 7 parts of glycerine, and to each 100 grams of the mixture, i gram of strongest carboUc acid. Warm for 10 to 15 minutes with constant stirring, until the flakes from the car- bolic acid disappear. Filter through previously moistened glass wool. Warm as needed, and remove with a glass rod. Glycerine jelly is sold by all dealers. Glycerine Gum. Dissolve 10 grams of gum arable and 2 grams of glycerine in 10 cc. of water. Hydrochloric Acid, Concentrated. Iodine in Potassium Iodide. Dissolve 0.05 gram of iodine and 0.2 gram of potassium iodide in 15 cc. of water. Iodine Tincture. Dissolve in 95 per cent alcohol sufficient iodine to make a fight coffee- colored solution. All iodine solutions deteriorate on keeping, particularly if exposed to the fight. Labarraque's Solution (chlorinated soda). Thoroughly triturate 75 grams of fresh chlorinated lime (bleaching-powder) with 600 cc. of water, added in two or three successive portions, and filter. To the filtrate add a solution of 150 grams of crystallized sodium carbonate in 400 cc. of water, mix thoroughly, warm if the solution gelatinizes, and again filter. The solution gradually loses strength on standing, and should be kept in stoppered bottles in a cool, dark place. Javelle Water (chlorinated potash) may be prepared in the same manner, substituting 58 grams of potassium carbonate for the sodium carbonate. This reagent is used for the same purpose as Labarraque's solution. Millon's Reagent. Dissolve metaUic mercury in an equal weight of concentrated nitric acid and dilute with an equal volume of water. The solution should be freshly prepared. Nitric Acid, Concentrated. Olive Oil. Paraffine. ' Phoroglucin Tincture. Dissolve o.i gram in 10 cc. of 95 per cent alcohol. The solution deteriorates on keeping. Potash Solution. Dissolve 5 grams of caustic potash (potassium lo PREUMIN/1RY. hydrate) in ico cc. of water. If desired, caustic soda may be substituted for caustic potash. The term "alkali " as used in this work refers to one or the other of these solutions. Sajranin Solution. Prepare a saturated water solution, and dilute as needed. Schultze's Macerating Mixture. Mix a few crystals of potassium chlorate with concentrated nitric acid immediately before using. Schweitzer's Reagent ("ammoniacal copper solution," "cuprammonia," "cuoxam"). Precipitate cupric oxyhydrate from a solution of copper sulphate by adding a sUght excess of caustic soda or ammonia, filter and thoroughly wash. Dissolve the moist precipitate in strong ammonia with the aid of heat, cool, and filter from the precipitate which forms. It should be freshly prepared, and kept in the dark. Soda Solution. Five per cent solution of caustic soda (sodium hydrate) may be substituted for potash solution as a clearing agent. In the crude- fiber process, and for removing dark coloring matters, ij per cent solu- tion is used. Sulphuric Acid. The concentrated acid is employed in several tests. It should be diluted to ij per cent for use in the crude-fiber process. Turpentine (spirits or oil of turpentine). Xylol. COLLECTIONS. A collection of the vegetable materials used as foods or food adulterants and mounts of such materials are as indispensable to the food microscopist as is an herbarium to a systematic botanist. Many points of structure and special reactions can be learned with the aid of such collections which cannot be properly described in words or illustrated by figures. Standard Materials. The collection should include not only the fruits, seeds, barks, leaves, rhizomes, flowers, and other whole materials, but also the various products prepared from them. Many of these may be obtained from grain dealers, grocers, seedsmen and pharmacists, others may be collected in the field or garden. Powders are conveniently stored in screw-top bottles, which have the 'advantage over glass- or cork- stoppered bottles that they more completely exclude dust. Fruits, vege- tables, and other succulent materials are preserved in alcohol or formalde- hyde. Especially useful is the collection of economic seeds prepared under the direction of Frederick V. Coville, Botanist of the United States Depart- ment of Agriculture, by Gilbert H. Hicks, also the cabinet of materia medica specimens supplied by Parke, Davis and Company, Detroit, Mich., U. S. A. Microscopic Mounts. Powders such as flour, meal, and starch are best mounted in water as occasion demands, but sections and other difli- cultly prepared specimens should be at hand in permanent form. The collection of mounts may be prepared either by the microscopist himself, or by a skilled worker from material of his selection. At present suitable collections of mounts are not on the market PREPARATION OF MATERIALS FOR EXAMINATION. MECHANICAL PREPARATION, Cross-sections. In studying standard material cross-sections are indispensable, as they show the number and arrangement of the cell layers and certain details of structure. Longitudinal and tangential sec- tions are of lesser importance. Sections are also useful in the examina- tion of coarsely ground commercial products, such as ground coffee and other materials containing fragments large enough for cutting. It should be remembered, however, that sections play a comparatively unimpor- tant r61e in diagnosis, as most of the materials which the microscopist is called upon to examine are fine powders and other preparations in which the tissues have been torn one from another, and can only be studied in surface view or as isolated elements. Considerable discretion is required in the treatment prehminar}- to the cutting of sections. As a rule, dried materials are best cut after soaking in water for some hours or until thoroughly softened, although cruciferous seeds and some other materials are best cut dry. Succulent fruits and other fresh materials should be hardened in 50 per cent alcohol. Only in the investigation of very delicate tissues is it desirable to resort to the tedious process of impregnating with paraffinc or collodion. Large objects are held between the thumb and first finger during cut- ting, small objects between pieces of elder pith, sticks of soft wood, or in a hand vise, or else they are embedded in paraffine or glycerine gum. Wood for holding materials during cutting should be sawed across the grain into sticks so that the razor or microtome knife will cut with the grain. Glycerine gum is used not merely to embed the object, but also to attach it to a piece of elder pith. The sections are cut after the ^um has hardened. Paraffine may be used not only for dry materials, whether or not impregnated with paraffine as described below, but also for fresh material or material softened in water, provided the outer surface is carefuHv dried PREPARATION OF MATERIALS FOR EXAMINATION. 13 to insure contact. It should have a melting-point of 54° or 74° C, and is conveniently molded into sticks by melting at the lowest possible temperature and pouring slowly into a glass or metal tube. The stick may be loosened from the tube by gentle heating. The object is introduced into a cavity in the end of the stick, and the parafhne melted about it with a hot wire or needle. The section razor used for cutting soft objects should have a keen, thin edge, but for cutting nut shells and other hard tissues another razor with a beveled edge should be in readiness. Both are kept in order by honing and stropping. The microtome is a convenience but not a necessity, being used almost exclusively in preparing permanent mounts for the collection or in diffi- cult investigations. Many food microscopists use only a razor. Impregnating and Embedding with Paraffine or Collodion is best carried out with material preserved while fresh in 50 per cent alcohol, although dry material may be soaked in water until the tissues are softened and then transferred to 50 per cent alcohol. To facilitate the process, seeds and small fruits should be cut in half, and other materials in as small pieces as practicable. In carrying out the paraffine process the object is immersed successively in the following : 65, 80, and 95 per cent alcohol, absolute alcohol, a mix- ture of equal parts of xylol and absolute alcohol, xylol, a mixture of xylol and paraffine (melting at 43° C), 43° paraffine kept at 50°, and finally 54° paraffine kept at 60°. The time required for permeation in each of these varies, according to the size and nature of the object, from one to several days. Finally the object is removed from the paraffine to a suit- able mold, covered with melted paraffine, and allowed to cool. If the collodion process is followed, the object is treated with 50, 65, 80, and 95 per cent alcohol and absolute alcohol as above described, but is removed from the latter to absolute ether, then to a mixture of ether and collodion, and finally to pure collodion. It is then transferred to a paper mould, covered with collodion, and, when the latter has solidified, the whole is placed in 80 per cent alcohol, where the collodion in some hours forms a cartilaginous mass enveloping the object. Sections of fruit stones and nutshells are cut with a fine saw and after being attached to a slide by hot Canada balsam are ground down to the desired thickness on a whetstone. They are finally mounted in balsam. Surface Sections are useful in studying epidermal tissues, fruit and seed coats, and other cell aggregates forming distinct layers. They are much 14 PRELIMIN/IRY. easier to prepare than cut sections. Dried materials should be soaked in water, after which the layers may usually be removed by scraping or stripping. The separation of the coats from very small seeds is often facilitated by soaking for some hours in dilute {i\ per cent) caustic soda. Boiling with dilute soda is sometimes desirable, particularly if the layers contain coloring matters which render them opaque. The epidermal layers of fruits can often be separated by plunging into boihng-hot water. The bran coats of cereals, the seed coats of legumes, and oil seeds, and the various layers of spices and other materials may be studied in fragments picked out from the coarsely ground products with forceps or separated by sifting. Even in quite finely ground products one often finds large enough fragments for studying in surface view not only the characters of the individual cells, but also the arrangement of the cells in the layers. The different layers in surface sections may become separated from one another or they may remain in their original position one on top of another. In the latter case it is often possible by careful focusing not only to study successively the layers, but also to determine their order of arrangement. This is greatly facilitated by noting in preparing the mount whether the outer or the inner surface is uppermost, and also by comparison with cross-sections. Some materials which have no ven- characteristic single layer can be identified by the combination of several cell layers and their order of arrangement. Powders. Since the food microscopist is called upon to examine powders more often than any other class of products, he should familiarize himself with the microscopic characters of standard materials in powder form. Tissues in definite layers, such as epidermal cells, the bran coats of cereals, and the coats of various seeds, have much the same appear- ance in the ground material as in surface preparations ; except that in fine powders the fragments are smaller, and radially elongated elements, such as the palisade cells of legumes and cotton seed, often fall on their sides, presenting the same appearance as in cross-section. Cells not in layers, such as make up the endosperm of cereals and the cotyledons of legumes, do not present a striking appearance in powder form, although the contents of their cells, being liberated by the rupture of the cell-walls, may be studied to advantage. Stone cells, vessels, and other detachable elements are also striking objects in powders. Commercial Powders should first be examined under a simple micro- scope, either before or after separation into grades by sifting, and fragments PREPARATION OF MATERIALS FOR EXAMINATION. 15 picked out for subsequent examination under the compound microscope. Mounts representing the whole material should also be made. If the powder is too coarse for mounting directly, it may be reduced to an im- palpable powder in an iron mortar, or a small portion may be crushed on the slide with a scalpel. Special instructions for the examination of flour are given on p. 54, of cereal cattle foods on p. 59, of ground oil cakes on p. 171, and of ground spices on p. 497. ' Pulps. The flesh of ripe fruits may be examined as a pulp, hard elements, such as vessels and stone cells, being especially distinct in such preparations. The same method is used for commercial jams, jellies, pastes, etc. Maceration by Schultze's method is useful in reducing hard materials to a pulp, thus isolating the elements. The process consists in cautiously heating a small amount of the material in a capsule with concentrated nitric acid and a few crystals of potassium chlorate. As soon as the tissues are sufficiently disintegrated, the solution is diluted with water and the fragments washed thoroughly by decantation. TREATMENT WITH REAGENTS. Mounting in Water. Although water is usually regarded as an inert substance, it serves in microscopic work as the most important of all reagents ; in fact, if we had no other we would still be able to carry on our work with reasonable success. Water dissolves sugars, gums, certain proteids, and other cell-contents, and in addition swells and partially dissolves constituents of the cell-walls. Most of these soluble substances have no marked microscopic characters, whereas the insoluble constituents, including starch and calcium oxalate among cell-contents, and cellulose, lignin, suberin, and cutin of cell-wall constituents, occur in striking and often highly characteristic forms. For these reasons water is especially suited as a microscopic medium, although it cannot of course be used for permanent mounts. In the water mount we first observe whether starch is present, and if so, note the characters of the grains. Addition of iodine solution dif- ferentiates the starch grain from other bodies. We next turn our atten- tion to the other elements, particularly the tissues. Starch, if present in considerable amount, obscures the tissues, but can be converted into a paste and thus rendered transparent by heating the mount to boihng 1 6 PRELIMINARY. over a lamp, replacing the water lost by evaporation. This boiling, which takes the place of treatment with alkah, chloral, or other clearing agents, also renders the tissues more distinct by swelling the cell-walls. Air bubbles may be removed from a section by soaking in a considerable amount of recently boiled water. Treatment with Iodine colors the starch grains of water mounts blue, proteid matter yellow-brown, and cellulose, hgnin, and other cell-wall substances various shades of yellow. The solution in potassium iodide acts more rapidly than the tincture, ' coloring the starch grains a deeper shade of blue. If the tincture is added directly to the dry or alcohol material, starch grains are colored brown-yellow, changing to blue on dilution with water. Treatment with iodine and then with strong sulphuric acid colors cellulose blue, lignified, suberized, and cuticularized tissues yellow. Chlor- zinc iodine gives much the same color reactions as iodine and sulphuric acid, and is more convenient. The best results are secured if the prepara- tion is first soaked in water. Treatment with Oil Solvents. Products containing a large amount of fat, oil, or essential oil can be studied to advantage only after treatment with chloroform, ether, turpentine, or some other oil solvent. Sections may be soaked in the solvent in a covered watch-glass, and powders may be extracted on a filter or in a fat extractor. More convenient methods, provided subsequent treatment with reagents is not needed, are to mount the section or powder directly in turpentine, which dissolves the oil, or else in olive or almond oil which mix with the oil of the product. These methods are especially useful in the study of aleurone grains. Clearing. Alkalies (potassium or sodium hydrate) are the most serviceable clearing agents for general use. The treatment may be per- formed on the slide either by mounting directly in dilute alkali or by adding a small drop of 5 per cent alkali to a water mount, or in the case of dark- colored tissues by boiUng with i^ per cent caustic soda. Alkali dissolves starch, proteids, various coloring matters and other cell-contents. It also swells the cell-walls, and to some extent expands compressed tissues. Chloral Hydrate acts more slowly than potash and soda, but has the advantage that it does not distort greatly the tissues. Labarraque Solution (chlorinated soda) and Javelle Water (chlorinated potash) are admirable reagents for bleaching tissues and expanding com- pressed cells- Thev are particularly adapted for sections, but owing to PREPARATION OF MATERIALS FOR EXAMINATION. 17 the difficulty of removing the bubbles, are less suited for powders. Sec- tions should be soaked in the reagents (diluted if necessary) until the desired result is attained, and then washed in water and finally in very dilute acetic acid. They become so transparent by this treatment that staining with safranin or some other dye is usually essential. Crude Fiber Method. This process serves not merely for the quan- titative determination of crude fiber, but also for clearing the tissues for microscopic examination. After weighing the crude fiber a small quantity may be removed for examination without introducing a per- ceptible error in the subsequent determination of ash. The action is so energetic as to destroy dehcate tissues; but is valuable in clearing stone cells and other sclerenchyma elements. The process (which may be abbreviated if used merely for clearing) is as follows: Extract 2 grams of the finely ground material with ether, place in a 500 cc. Erlenmeyer flask, and add 200 cc. of boiling 1.25 per cent sulphuric acid. Loosely cover the flask, heat at once to boiling, and boil gently thirty minutes. Filter on a paper, wash with hot water, and rinse back into the same flask with 200 cc. of boihng 1.25 per cent sodium hydroxide solution nearly free from carbonate. After boihng, as before, for thirty minutes, collect the fiber on a weighed paper, thor- oughly wash with hot water, and finally with a little alcohol and ether. Dry to constant weight at 100° C, and weigh. Deduct the amount of ash in the fiber, as determined by incineration, from the total weight. Staining. Great numbers of stains have come into use for staining cell-walls and cell-contents. Safranin, a stain strongly recommended by Strasburger, has the advan- tage over most other stains in that it differentiates very beautifully the tissues, and does not, hke most coal-tar colors, fade in glycerine mounts. The best results are secured by soaking the section for some time in a rather dilute water solution. Overstaining, with subsequent removal of the excess with alcohol, is often advantageous. Treatment with Other Reagents is carried on in a watch-glass, or on the shde, as occasion demands. In the latter case the material is either treated directly with a drop of the reagent, or it is first mounted in water, and a drop of the reagent is drawn under the cover-glass by means of a piece of filter-paper placed on the opposite side. Sections of impregnated material are attached to a slide by means of Meyer's albumen fixative, then soaked in chloroform or xylol until l8 PRELIMINARY. the paraffine is dissolved, and finally treated with reagents and stains ad libitum. Permanent Mounting. The technical microscopist, as well as the investigator, often has occasion to mount in permanent form objects of special interest. If the material contains a large amoimt of oil, or if it has been impregnated with paraffine, these should be removed by treatment with chloroform, xylol, or other oil solvent. Objects which have been cleared with alkah or Labarraque's solution should be washed thoroughly in water and finally in very dilute acetic acid. Most other reagents can be removed by water or alcohol. Staining is advisable if the tissues are both colorless and transparent, and is essential if Canada balsam is employed as the mounting medium. Air bubbles may be re- moved by boihng or allowing to soak in a considerable bulk of freshly boiled water. Slides and cover-glasses must be scrupulously clean and free from finger prints. The process of mounting is quite simple. A suitable sized drop of the mounting medium is placed in the center of the sHde, the object is transferred to this, and the cover-glass is placed in position by means of forceps. If too much of the medium is used, the excess is removed with a piece of filter-paper; if too little, more is added from one side. The mount is finally ringed with two or more coats of cement. It is well to keep the slide on the turn-table not only during ringing, but also while mounting, thus facihtating the centering of both object and cover-glass. Mounting in Glycerine. A mixture of equal parts of glycerine and water is the best single medium for our purpose, since wet objects may usually be mounted directly without staining or dehydrating, and can be removed at any time for further treatment with reagents. The mounting is greatly facihtated by so gauging the size of the drop that it exactly fills the space beneath the cover-glass. If more is added, or an excess removed, care should be taken to clean thoroughly the slide about the cover-glass with a filter-paper, otherwise the cement will not stick to the glass. The mount should be ringed two or three times with a good cement, allowing it to dry at least 24 hours between the coats.i Mounting in Glycerine Jelly requires less skill than mounting in glyc- erine, but the heating necessitated by the process injures some materials, ' The writer uses "King's Transparent Cement" for the first coat, and "King's Lacquer Cell and Finish" (red or blue) or "White Zinc Cement" for the finishing coats, the three colors being used to distinguish respectively cross, surface, and longitudinal sections. PREPARATION OF MATERIALS FOR EXAMINATION. 19 and, furthermore, the objects are not so readily removed should occasion demand. A small cube of the solid or a drop of the melted jelly is placed on the slide and heated gently until fluid throughout. The object, which may be taken from water or glycerine, is then introduced, and the cover-glass, previously warmed to prevent introduction of air bubbles, is placed in position. After cooling, the excess of the jelly should be carefully removed, and the mount ringed, as described for glycerine mounts. Mounting in Canada Balsam can be carried out only with objects freed from water. Dehydration is effected by soaking in 95 per cent alcohol, absolute alcohol, and finally in xylol, chloroform, or oil of cloves. Stain- ing is essential for objects with colorless tissues. A drop of the xylol balsam is placed in the center of the slide, the object is introduced, and the whole is covered with a slightly warmed cover-glass. More balsam is added if, after standing, the space under the cover-glass is not entirely filled. After the balsam has thoroughly hardened, the excess may be removed and the mount ringed with colored cement; this, however, is not essential, for the mount is permanent with- out it. BIBLIOGRAPHY.l Behrens: Guide to the Microscope in Botany (Trans, by Hervey). Boston, 1885. Chaaiberlain: Methods in Plant Histology. Chicago, 1901. Lee: The Microtomist's Vade Mecum. Philadelphia, 1900. Steasburger and HiLLHOusE : Handbook of Practical Botany. London, 1900. Zimmermann: Botanical Microtechnique (Trans, by Humphrey) New York, 1901. ' Works in English. ' ' THE PRINCIPAL HISTOLOGICAL ELEMENTS. TISSUES. Parenchyma (Fig. i) is a general tenii for the simpler forms of tissues, with thin walls composed usually of cellulose. The common types of parenchyma cells are either isodiametric or somewhat elongated, and may or may not have intercellular spaces at the angles. If the walls are Fig. I. Parenchyma from the stem of maize, gw double wall between two cells; s inter- cellular space produced by splitting of the double wall. (Sachs.) of cellulose, chlorzinc iodine colors them blue and Schweitzer's reagent dissolves them. Spongy Parenchyma (Fig. 2) is a loose spongy tissue with numerous intercellular spaces of considerable size. Collenchyma (Fig. 3) is characterized by conspicuous thickenings at the angles of the cells. The cell-wall is composed of cellulose, or a modi- fication known as coUenchym. This form of tissue occurs most com- monly in subepidermal layers. Sclerench3nna includes a great variety of tissues with thickened walls composed chiefly of lignin. The walls of these cells as . first formed are pure cellulose, lignin being deposited on the inner surface of the walls during subsequent growth. Chlorzinc iodine colors the walls yellow THE PRINCIPAL HISTOLOGICAL ELEMENTS. 21 or yellow- brown ; phloroglucin and hydrochloric acid, pink; aniline sul- phate, deep yellow. Stone Cells (Fig. 4) are isodiametric, or moderately elongated scleren- chyma elements, with thickened walls and conspicuous pores. They occur either singly or in groups in parenchyma, or form dense tissues, such as the shell of the cocoanut and the stone of the peach. RG. 2. Spongy Parench3'ma from the hull (spermoderra) of the common pea. (MOELLER.) Fig. 3. Epidermis and CoDenchyma from the petiole of Begonia, v thickened wall of collenchyma; chl chlorophyl grains. (Sachs.) Sclerenchyma Fibers (Fig. 5) occur in various parts of plants. Those found in fibro-vascular bundles are known as Bast Fibers. Other sclerenchyma tissues are found in stems, leaves, the coats of fruits and seeds, and in various organs. Epidermal Tissues have certain characteristics pecuHar to their posi- tion. They are usually covered by a membrane known as the " cuticle, " composed of cutin, a substance related to hgnin and suberin. Wax, silica, calciiun carbonate, and calcium oxalate also occur as epidermal incrustations. Stomata are made up of pecuharly differentiated epidermal cells. (See pp. 28-30.) Hairs and Glands, including many beautiful and characteristic forms, are unicellular or multicellular outgrowths of epidermal layers. 22 PRELIMINARY. Cork Cells form protective layers on stems and other parts. The cells are arranged in radial rows, and are polygonal in surface view, quadri- lateral in section. Suberin, the characteristic constituent, is repellent of water. Fibro-vascular Bundles (Figs. 6 and 25). The conducting elements of plants are commonly grouped into vascular or fibro-vascular bundles, of which the nerves of leaves and the strands of stems and roots are examples. Fig. 4. Stone Cells from the shell of the cocoanut. (Winton.) Fig. 5. Bast Fibers from the bark of Sambitcus nigra. (VoGL.) A bundle is made up of two distinct parts: (i) the xylem, wood or had- rome, consisting of vessels, tracheids, and other lignified elements, and (2) the phloem, bast or leptome, consisting of sieve tubes, cambiform cells, and other non-lignified elements. Groups of bast fibers usually accompany the bundles. For details as to the arrangement of xylem and phloem see pp. 39-45. The Vessels of the xylem, also known as ducts and tracheae, are thin- walled tubes with annular, spiral, scalariform or reticulated thickenings, or thick- walled tubes with pits or pores. Tracheids resemble vessels in their markings, but consist of rows of cells placed end to end, not open tubes. THE PRINCIPAL HISTOLOGICAL ELEMENTS. 23 Sieve Tubes, the characteristic elements of the phloem, are thin-walled, elongated cells, with perforated transverse partitions known as sieve plates. These sieve plates also occur to some extent on the longitudinal walls. Both the sieve tubes and the accompanying cambiform cells are com- posed of cellulose. Bast Fibers (Fig. 5) are long, pointed cells with lignified walls. Pores through which pass diagonal, crossing fissures are usually evident. Fig. 6. Fibro-vascular Bundle from the mesocarp of the cocoanut, in longitudinal section. ste stegmata; Si silicious body; / bast fibers; t tracheids with small pits; t' tracheids with large pits; sp spiral vessel; r reticulated vessel; sc scalariform vessel; i sieve tube; c and c' cambiform cells. (Winton.) Latex Tubes (Fig. 341). These are branching tubes containing milky secretions, found in various stems and roots, and occasionally in fruits. CELL-CONTENTS. Protoplasm, the living matter of the vegetable cell, includes : (i) cyto- plasm, which in the growing stage is a viscous, stringy, more or less granu- lar substance, but in the dried material has no marked characters; (2) the cell nucleus, a rounded body differentiated by staining and often evident without; and (3) the plastids or chromatophores, including the chloro- plasts, leucoplasts, and chromoplasts. Chloroplasts, or chlorophyl grains, occur in all green parts, and play an important r61e in assimilation (p. 29.) Leucoplasts are inconspicuous, colorless bodies instrumental in the formation of starch (p. 644). 24 PRELIMINARY. Chromoplasts are orange or yellow bodies of various shapes to which certain organs owe their distinctive color. Proteids occur either in amorphous form or as aleurone grains. On heating with Millon's reagent they form a reddish deposit; on treatment with iodine solution they are colored yellow or brown. Aleurone Grains (Fig. 7) are found in the perisperm, endosperm, and embryo of seeds, particularly oil seeds, and like starch grains have marked Fig. 7. Aleurone Grains; in the center two cells filled with aleurone grains. (T. Hartig.) microscopic characters, which are often characteristic of the species or genus. These grains vary in size from less than i // to over 50 [i. Among the numerous shapes are round, oval, irregularly swollen, angular, and warty forms. They are colored yellow or brown by iodine solution and take up readily certain aniline dyes, hasmatoxylin, and other stains. Being partly soluble in water, they should be mounted either in glyc- erine after extraction of the oil in which they are often embedded, or directly in oil or turpentine. Each grain consists of a ground substance, in which are usually embedded one or more crystalloids, one or more globoids, and often a crystal rosette of calcium oxalate, the whole being inclosed in a thin membrane. 1. The ground substance consists of amorphous proteid matter, and is usually soluble in water, although after previous standing in alcohol it dissolves slowly. It is also soluble in dilute alkali, acids, and various reagents, but is not affected by oil or oil solvents. 2. Crystalloids are proteid crystals belonging to the isometric or hex- agonal system. In some species they are so large that a single crystalloid makes up the bulk of the grain, in others they are very minute. For the most part they are insoluble in cold water, but dissolve in very dilute alkali (less than i per cent), dilute acetic or hydrochloric acid. They are insol- THE PRINCIPAL HISTOLOGICAL ELEMENTS. 25 uble in saturated solution of picric acid (distinction from globoids ) and in saturated solution of sodium phosphate (distinction from all other con- stituents of the grains). 3. Globoids, according to Pfefifer, consist of lime and magnesia combined with phosphoric acid and an organic acid. They are usually globular, of uniform transparent structure, and are not colored by iodine solution. They are insoluble in both cold and hot water, but unlike crystalloids are soluble in saturated solutions of picric acid and sodium phosphate and insoluble in dilute potash. 4. Calcium oxalate occurs as single crystals or as crystal rosettes. These are insoluble in water, alkali, and acetic acid, but dissolve readily in dilute hydrochloric acid. Alkaloids are nitrogenous substances, often with marked stimulating or toxic properties. Some, such as morphine and piperine, are crystalline solids, others, such as nicotine, are liquids. Caffein and theobromin are often classed as alkaloids. Starch. See pp. 643-650. Sugars occur in solution in certain stalks, roots, and fleshy fruits, and in the form of crystals in dried fruits. Crystals are readily seen in alcohol or glycerine mounts of raisins, figs, dates, etc. Cane-sugar crystalUzes in monoclinic prisms. It does not reduce Fehling solution. Invert-sugar consists of equal parts of dextrose and levulose, and is formed by the spUtting up or "inversion" of cane-sugar. In many fruits both cane- and invert-sugar are present, although as a rule the large fruits contain much more cane-sugar than the small fruits. As both dextrose and levulose are reducing sugars, they are detected by heating the dry object to boiling in a drop of FehUng solution diluted with two drops of water. The red precipitate of copper suboxide thus formed is often evident to the naked eye. Other sugars occurring in plants are rafinose, maimit, dulcit, mehtose, etc. Inulin is a water-soluble carbohydrate found in the roots of the dande- lion and other composite plants. In alcohol material it forms sphaero- crystals ; in dried material, colorless, irregular lumps. Gums. These include various mucilaginous substances, some of which are formed in the cell, others are derived from the cell-walls. They swell in water and are precipitated by alcohol. Glucosides are compoimds of sugars with organic acids. Some of 26 PRELIMINARY. them, such as hesperidin, form needle-shaped crystals insoluble both in water and dilute adds. Tannins are themselves colorless, but are usually associated with brown coloring substances. In the fresh material they are in solution, but on drying they impregnate the tissues or form brown deposits. With iron salts they become dark blue or green. Fats and Fatty Oils rank with carbohydrates and proteids in impor- tance. They occur in all parts of the plant, but are especially abimdant in certain seeds, where they serve as reserve material. The fats may form amorphous masses, or beautiful crystals, while the oils occur as globules. Both are soluble in ether, chloroform, benzine, turpentine, and xylol, and form soaps with alkalis. With few exceptions they are insoluble in alco- hol. On treatment for some hours with alcanna tincture, all fatty sub- stances, as well as resins and essential oils, take on a beautiful red color. Waxes are closely related to fats. Essential Oils and Resins are formed in glands or secretory cavities, and are distinguished from fats and fatty oils by their solubility in alcohol. Fig. 8. Crystals of Calcium Oxalate, a large single crystal; c crystal rosette or cluster ; b intermediate form. (Kny.) Calciiun Oxalate. Lime is one of the elements essential for plant growth, its chief function being to render poisonous oxalic acid harmless by conversion into insoluble calcium oxalate. MonocUnic, or rarely tetragonal, crystals of this salt occur in certain tissues, and are often of great service in diagnosis. Four distinct forms deserve special mention: (i) crystal clusters or rosettes (Fig. 8, b and c), (2) large single crystals (Fig. 8, a), (3) raphides or needle-shaped crystals (Fig. 9), and (4) crystal sand or deposits of numerous minute crystals (Fig. 10). THE PRINCIPAL HISTOLOGICAL ELEMENTS. 27 Calcium oxalate is distinguished from all other crystalline substances by its insolubility in water, alkali, and acetic acid, its solubility without Fig. 9. Raphides of Calcium Oxalate from the flesh of the pineapple. (WiNTON.) Fig. 10. Crystal Sand of Calcium Oxalate from the leaf of belladonna. (Winton.) effervescence in dilute hydrochloric acid, and the formation of crystals of calcium sulphate with sulphuric acid. Calcium Carbonate is present in certain plants as concretions or cystoliths (Fig. 169, cy), less often as crystals. It dissolves in dilute hydrochloric acid with effervescence. Silica forms an incrustation on certain epidermal tissues, and less often occurs as warty bodies in peculiar cells known as stegmata (Fig. 6, Si). BIBLIOGRAPHY.^ De Bary: Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns (Trans, by Bower and Scott). London, 1884. GooDALE : Physiological Botany. I. Outlines of the Histology of Phaenogamous Plants. New York, 1885. Strasburger, Noel, Schenck, and Schimper: A Text-book of Botany (Trans. by Porter and revised by Lang). London, 1903. ' Works in English. MORPHOLOGY OF ORGANS. ' THE LEAF. Leaves are specially developed for carrying on three processes: (i) assimilation (photosynthesis), or the formation of organic matter through the agency of light from carbonic acid and water, v^rith exhalation of oxygen; (2) respiration, or the oxidation of organic matter, with exhala- tion of carbonic acid; and (3) transpiration, or exhalation of water drawn up from the soil. As a rule they expose a large surface to the air, and have Fig. II. Leaf in Cross Section of Marshmallow (Althaa officinalis), e upper epidermis; p palisade cells and p' spongy parenchyma of the mesophyl; e' lower epidermis; h hairs; d glandular hairs; st stomata; K calcium oxalate rosette. (VoCL.) special adaptations for facilitating or preventing communication with the air, according to the needs of the plant. A cross-section of a leaf (Fig. 11) shows that it is made up of a middle layer or mesophyl of green tissues with a network of veins, between two colorless cuticularized epidermal layers. 28 MORPHOLOGY OF ORGANS. 29 The Lower Epidermis (Fig. 12) consists of ground cells interspersed with stomata, and often with hairs or glands. The ground cells in surface view differ greatly in character according to the species. Some are sharply polygonal, or quadrangular, with straight walls, others have ill-defined angles and wavy walls, and others still are irregular in outline. The walls may be thin or thick, porous or non-porous; the cuticle smooth or wrinkled. Stomata are slits between two hemi-elliptical guard cells, which when open allow free access of air to the mesophyl. In some leaves two or more modified cells, known as accompanying cells, adjoin the guard cells. The Fig, 12. Epidermis with Stomata from the leaf of Hydrangea Hortensia, in surface view. (MOELLER.) guard cells of the stomata are the only cells of the epidermis containing chlorophyl grains. In addition to ordinary or air stomata a larger form known as water stomata occurs on some leaves. Hairs and Glands (secretory hairs) present an endless variety of beau- tiful and characteristic forms. All hairs whether unicellular or multi- cellular are epidermal outgrowths, but Emergences are made up of tissues belonging both to the epidermis and the mesophyl. The Mesophyl in the under part of the leaf forms a spongy parenchyma, (Fig. II, p') thus facilitating assimilation, respiration and transpiration, but in the upper part it is a close tissue, often consisting of one or more layers of palisade cells (p.). Chlorophyl grains are present in all the mesophyl cells, but are most abundant in palisade cells of the upper layers (Fig. 11, p). They are rounded bodies varying up to 12 // in diameter. They consist of granules (some green, others colorless) , proteid matter and starch grains, embedded in a ground substance and surrounded by a membrane. During assimila- 30 PRELIMIN/IRY. tion starch is continually being formed in these grains, but is soon dis- solved and translocated to other parts of the plant. In dried leaves the chlorophyl grains are more or less brown in color, and lack distinct char- acters. The Fibro-vascular Bundles of leaves are strongly developed in the midribs and main branches, but in the smaller branches are rudimentary. Spiral vessels are particularly abundant. Other elements which may occur in the mesophyl are stone ceUs, crystal cells, resin cavities, oil cells, latex tubes, etc. The Upper Epidermis may or may not be similar to the under epidermis in structure, but as a rule stomata are less abundant or absent. Preparation of Materials. Sections are cut with a razor, holding the leaf between pieces of pith. In the case of thin leaves it is advisable to cut into several strips, place one on the other, and section aU together. Pieces of the epidermis are readily stripped ofi from moist leaves with forceps. In powdered leaves the elements are isolated by squeezing under the cover-glass. THE FLOWER. Although the four parts of the flower — sepals, petals, stamens, and pistils — are metamorphosed leaves, usually only the sepals, less often both sepals and petals, resemble leaves in outward appearance and structure. Cal3rx. The sepals, like leaves, consist of mesophyl between two epidermal layers. Stomata and often hairs are developed on one or both epidermal layers. The mesophyl parenchyma usually contains chlorophyl, but a well-developed pahsade layer is seldom present. Bundles are more or less strongly developed. Corolla. The petals are of various colors and commonly of delicate texture. Each consists of two epidermal layers and a middle tissue of elongated parenchyma (corresponding to the chlorophyl parenchyma of leaves) through which pass delicate bundles. Stomata are usually lack- ing, but hairs and papillae are often present. Spiral vessels, and less often crystal fibers, are present in the bundles. The coloring matter of the fresh petal is usually dissolved in the cell-sap, seldom in the form of chro- moplasts. The perfume of flowers is due to essential oils present in the cell-sap, in special cavities (nectaries), or in glands MORPHOLOGY OF ORGANS. 31 Stamens. Each consists of a slender, cylindrical (less often flattened, leaf-like) filament, bearing at the apex an anther with a pair of pollen sacs on each side of the central bundle (Fig. 13). On ripening, the sacs Fig. 13. Anther of Datura Stramonium in cross section, c connective tissue with fibro- vascular bundle; a outer pollen sacs; p inner pollen sacs. (FranKi) of each pair unite, and finally the wall opens by a slit or pore, liberating the pollen grains. The walls of the anthers (Fig. 14) are composed of an outer layer Fig. 14. Anther Wall in cross section showing the outer epidermis and the endothe- cium with reticulated walls. (Sachs.) Fig. 15. Pollen Grains, i, 2 heath; 3, 4 linden; S blueberry; 6, 7 marjoram; 8, g lavender; lo, II sage; 12, 13 balm; 14, 15 rosemary; 16, 17 flax; 18 white mullein; 19, 2omelilot; 21 willow herb; 22, 23 composite plants. (Villiers and Collin.) or epidermis, sometimes hairy, and an endothecium or inner layer of char- acteristic cells with narrow radial ribs forming reticulations. 32 PRELIMIN/IRY. Pollen Grains (Fig. 15) are mostly globular, rounded, or tetrahedral, either smooth or else covered with warts, bristles, or pits. They consist of single cells clothed with two membranes ; the outer thick, forming a kind of cuticle; the inner thin, forming the cell-wall proper. The con- tents consist of protoplasm, often with granules in suspension. When the ripe pollen is deposited on the stigma the protoplasmic contents burst Fig. 16. Pollen Grains and Crystals of Cane-sugar irom Honey, a pollen grains of furze; h of heath; c of some composite flower. (Hassall.) out through clefts, or more commonly through pores, forming tubes which penetrate through the tissues of the stigma and style into the ovule, effect- ing fertilization. The shape, size, and markings of pollen grains are often so characteristic as to permit the identification of the species, not only in powders, but also in honey, thus furnishing evidence as to the flowers visited by the bee (Fig. 16). The Pistil (Fig. 19) consists of stigma, style, and ovary, the latter enclosing the ovules. The stigma is clothed with clammy papillae, on which the pollen grains lodge. The style is long or short, with a central MORPHOLOGY OF ORGANS. 33 channel. It is made up of elongated elements. The ovary walls are of quite simple structure, but the fruits into which they ripen are often complex. THE FRUIT (PERICARP AND SEED). A fruit in its simplest form is a ripened pistil, consisting of pericarp or matured ovary wall, and one or more seeds or matured ovules. In some fruits, notably the apple and other pomes, the fruit flesh is developed from Fig. 17. Cocoanut Fruit. 5 lower part of axis forming the stem; A upper end of axis with scars of male flowers. Pericarp consists of Epi epicarp, Mes mesocarp with fibers, and End endocarp or hard shell; T portion of spermoderm adhering to endo- sperm; Alb endosperm surrounding cavity of the nut; K germinating eye. (Winton.) receptacle and ovary wall. If the flower has several ovaries, these on ripening form an aggregate fruit. A compound or multiple fruit consists of the united fruits of several flowers. The receptacle of aggregate and compound fruits is sometimes fleshy, forming the bulk of the fruit. Ex- amples are the strawberry, an aggregate fruit with nudets on the outside of a fleshy receptacle, and the fig, a compound fruit with nutlets on the inside of a hollow receptacle. PERICARP. The mature pericarp may be dehiscent (e.g. legumes, crucifers), or inde- hiscent, and in the latter case may be entirely fleshy (e.g. grape, banana, 34 PRELIMINARY. and other berries), entirely dry (e.g. acorn and other nuts), or partly fleshy and partly dry (e.g. peach and other drupes). It may be distinct from the seed or seeds (e.g. peach, legxunes), or united with the seed (e.g. cocoanut, wheat, and other cereals). Mes End Fig. i8. Coats of Bayberry {Laurus nobilis) in cross section. Pericarp or fruit coat consists of Epi epicarp, Mes mesocarp, and End endocarp; S spermoderm, testa, or seed coat. (Moeller.) Since the pericarp is the ripened pistil and the pistil is a metamorphosed leaf, all three are analogous in structure, each consisting of a middle layer between two epidermal layers. The mesocarp, or middle layer of fruits, is often however more complex in structure than the mesophyl of leaves. MORPHOLOGY OF ORGANS. 35 The Epicarp (Figs. 17 and 18, Epi), or epidermis of the pericarp, consists of a single layer of cells, often interspersed with hairs and rarely with stomata. The Mesocarp (Figs. 17 and 18, Mes) in some fruits forms a layer several centimeters or even decimeters thick, in others is scarcely thicker than a sheet of writing-paper. The hypoderm, consisting of one or more layers adjoining the epicarp, is often different in structure from the layers further inward. The remainder of the mesocarp may be homogeneous throughout except for fibro-vascular bundles, or may consist of several forms of cells (stone cells, oil cells, etc.) irregularly distributed in a homogeneous ground tissue, or arranged in distinct layers. The visible cell-contents include starch, sugar, oil, tannin, chlorophyl, calcium oxalate, and other substances. The Endocarp (Figs. 17 and 18, End), strictly speaking, consists of the innermost cell-layer,- but in the case of nuts, dupes, and other fruits the hard shell made up of numerous layers of stone cells is commonly desig- nated by this term. SEED. In order to understand the structure of the seed it is essential to con- sider the structure of the ovule from which it was developed, and the changes this undergoes after fertilization. An ovule (Fig. 19) consists of the body or Nucellus {s) in which is embedded the Embryo sac (t), the whole being enclosed by one, or more often two, coats or Integuments (p, q) with an opening at one end known as the Foramen (m). The Chalaza (0) is the base of the ovule where the integuments unite with the nucellus : the Hilum is the place of attach- ment with the support or Funiculus. In orthotropous and campylotro- pous ovules the chalaza is also the hilum, in anatropous and amphitro- pous ovules they are more or less separated, and are joined by a ridge known as the Raphe («). The pollen grains soon after they are deposited on the stigma of the flower send off tubes (klm) which penetrate through the style into the cavity of the ovary, and through the foramen into the nucellus, finally entering the embryo sac and effecting fertilization. As a result of this fertihzation the Embryo and the Endosperm are formed in the embryo sac, and these together with the Perisperm, consisting of the developed, or more commonly, degenerated nucellus, the Spermoderm, consisting of 36 PRELIMINARY. the matured integuments, and occasionally certain appendages, make up the seed. Either the embryo, the endosperm or the perisperm of the mature Fl&. 19. Flower of Simple Type in Longitudinal Section. Stamens consist of c filaments and a, b anthers (a cross section, b after dehiscence show- ing pollen grains). Pistil consists of h stigma with i pollen grains sending off tubes, one of which {klm) has reached and penetrated the ovule, g style, and / ovary, the walls of which later develop into the pericarp. Ovule consists of n funiculus (below) and raphe (above), o chalaza, p outer integument, q inner integument, m micropyle, s nucellus or body of the ovule, and t embryo sac in which] through the agency of « antipodal cells, v synergidee, and z oosphere, are developed the endosperm and the embryo. d bases of sepals; e nectaries. (Sachs.) seed may form the chief reservoir of reserve material, or, on the other hand may be reduced to a rudiment. MORPHOLOGY OF ORGANS. 37 This reserve material may consist chiefly of starch (e.g. cereals), of oil (e.g. cottonseed, linseed), or of cellulose (e.g. coffee, ivory nut). A B Fig. 20. Cardamom Seeds. A longitudinal section, X 3. B transverse section, X 5. p perisperm; e endosperm; em embryo. The reserve material in the perisperm is largely starch, in the endosperm and embryo it is oil and proteids. (Luekssen.) The Spermoderm, Testa, or Seed Coat, includes all the layers developed from the integuments of the ovule.^ It may be simple or complex, thin or thick, soft or hard. In some seeds it con- sists of but one or two thin layers (e.g. cereals), in others of five or six distinct layers, some of the layers being several cells thick (e.g. cucurbits). Among the common elements are thick- and thin- walled paUsade cells, stone cells, crystal cells, spongy parenchyma, and ordinary parenchyma. The "Nutritive Layer" found in some seeds is a parenchymatous tissue containing in the early stages of development reserve material, but later forming an ill-defined tin sue of empty compressed cells. The hilum, chalaza, and raphe of the ovule preserve their characters in the seed, while the foramen becomes more or less indistinct, forming the Micropyle. The raphe (present in anatropous and amphitropous seeds) is a bundle of vascu- lar elements with more or less distinct branches. The appendages of the Spermoderm include the Arillus or seed mantle, ' Some authors apply the term "testa" only to that portion of the seed coat developed from the outer integument of the ovule, the portion developed from the inner integument (if present) being termed "tegmen." This usage leads to confusion owing to the difficulty of tracing the origin of each layer. Fig. 21. tinseed in cross section. 5 spermoderm or seed coat ; E endo- sperm ; C cotyledons. The reserve material, consisting of oil and pro- teids, is partly in the endosperm and partly in the embryo. (Moeller.) 38 PRELIMINARY. the thickened (MOELLEE.) cell an outgrowth from the hilum, the Arillode, an outgrowth from the micro- pyle, and the Caruncle, a wart-Hke body formed on the micropyle, also bristles, wings, and other appendages which aid in disseminating the seeds. The Perisperm or Nucellar Tissue is usually a thin layer, often without cell struc- ture, but in black pepper and cardamom (Fig. 20, p) it forms the larger part of the seed and contains the store of reserve starch. The Endosperm constitutes the bulk of many seeds (e.g. cereals), but is almost ^ , , -, entirely absent in others (e.g. bean, crucifers). Fig. 22. Endosperm of Date •' v o > / Stone with reserve material in In the cereals the outer layer or layers of ^^ ^' the endosperm consist of aleurone cells, the remainder, of starch cells; in linseed the endosperm (Fig. 21, -E), which constitutes about half of the seed, con- tains aleurone grains and oil, but no starch; in coffee and the date stone (Fig. 22) the bulky endosperm contains reserve material in the form of thick- ened cell-walls. The Embryo is a young plant with Cotyledons or seed leaves. Radicle or young root, and Plumule or bud. It may be embedded in the center or one side of the endosperm (e.g. cereals, coffee), or it may constitute the bulk of the seed (e.g. legumes, crucifers, cottonseed). In the latter case the reserve material, which may be largely starch or oil, is located chiefly in the thickened cotyledons and radicle (Fig. 23). THE STEM (BARK AND WOOD). The stem is the axis connecting the leaf and root systems. It may be aerial or subterranean, simple or branched, herbaceous or woody. In some herbaceous plants it is exceedingly short, the leaves appearing to spring directly from the root, while in many herbaceous and all woody Fig. 23. Mustard Seed in cross sec- tion. Embryo consists of c folded cotyledons and r radicle. Reserve material, consisting of oil and pro- teids, is entirely in the embryo. (TSCHIRCH.) MORPHOLOGY OF ORG/INS. 39 plants it consists of an elongated trunk with or without a system of branches. Not only does the stem serve to mechanically support the leaves, but also, by means of the bundles, to distribute over the plant solutions of salts absorbed by the roots, of carbohydrates assimilated by the leaf, and of other organic substances formed in various parts of the plant. During the resting season large amounts of reserve material are stored in stems. AERIAL STEMS. The fibro-vascular bundles of phenogamous stems are collateral, that is, the phloem and xylem of each are in the same radial plane. Usually the phloem is entirely on the outer side of the xylem, but in some stems it is partly on the inner side (bicoUateral). In the stems of exogenous plants (dicotyledons and gymnosperms) the bundles with the parenchyma separating them are arranged in a zone between the pith and the cortex. The outer ring of the bundle zone con- tains the bast fiber groups, the middle ring, the phloem groups, the inner ring, the xylem groups. If the plant is perennial a ring of active cells or cambium soon forms between the phloem and xylem rings, adding each year new tissues to the inner side of the former and the outer side of the latter. The layers outside of the cambium constitute the bark, those between the cambium and pith constitute the wood. The bundles of endogenous plants (monocotyledons) are irregularly distributed through a parenchymatous ground tissue. There is no cam- bium and no differentiation into bark and wood. The following descriptions of annual and perennial stems apply only to exogenous plants: Annual Stems. The stems of herbaceous plants and the young stems of woody plants consist of at least four distinct zones : 1. Epidermis. This resembles the epidermis of the leaf. Stomata and hairs are often present. 2. Cortex. The tissue is largely parenchyma, often with outer layers of coUenchyma and inner layers containing either bast fibers or stone cells, or both. 3. Endodermis. This consists of a single layer of cells with thin but suberized walls. Starch grains are usually found in the cells. 40 PRELIMINARY. All the tissues inside of the endodemiis form the central cylinder or Stele. 4. Bundle Zone. The Phloem strand of each bundle consists of sieve tubes, cambiform cells, and parenchyma; the Xylem strand, of vessels (tracheae), tracheids (distinguished from vessels by the cross partitions), and parenchyma. The bundles are separated from each other by paren- chyma, developing in perennial stems into the medullary rays. Groups of bast fibers are commonly present in the outer parenchyma, or Pericycle. 5. Pith. This consists entirely of typical parenchyma. Perennial (Woody) Stems. The structure of perennial stems (Figs. 24 and 25) is much more com- plicated than that of annual stems, owing to the formation of secondary bark and wood by the cambium, also of cork and secondary cortex by the phellogen. The Bark includes all the outer part of the stem up to the wood. It is readily stripped off from the latter, especially during the spring, the separa- tion being through the deUcate cells of the cambium. Although many barks are used in medicine (e.g. cinchona, slippery elm, cascarilla), and in the arts (e.g. oak, hemlock), only cinnamon and its substitutes are of importance as foods. 1. Cork. With the increase in diameter of the stem the epidermis is ruptured and finally disappears entirely. In its place cork is formed by an active (meristematic) layer known as the Phellogen. As the cells of the phellogen divide by tangential partitions, the rectangular cork cells, as seen in cross sections, are in radial rows. They usually have suberized walls, and often contain dark contents with the reactions of tannin. As the stems continue to grow the primary cork often suffers the same fate as the epidermis, and is replaced by a secondary layer formed in the cortex by a new phellogen. This secondary cork may later be replaced by a tertiary, and so on. 2. Secondary Cortex, a thin-walled tissue hardly distinguishable from the primary cortex, is formed from the phellogen on the inner side. 3. Primary Cortex. The parenchymatous ground tissue often contains starch and crystals of calcium oxalate. Stone cells and bast fibers may also be present. The endodermis of old stems is not usually distinguishable from the other layers. 4. Pericyle. This may consist of parenchymatous ground tissue with MORPHOLOGY OF ORGANS. 41 isolated groups of bast fibers, or of a "mixed ring" composed chiefly of stone cells and bast fibers. 5. Bast. Like the phellogen, the cambium forms one kind of tissue on the outside, another kind on the inside. These are respectively the phloem and the xylem, a layer of each being produced each year. The phloem layers of different years' growth, together with the separating K^ ^-t 'T-'-i ■ "'-"r ■ '-r>-... '^--m Fig. 24, Branch of the Linden, in cross section, showing the bark and three annual layers of wood. (Kny.) partitions or medullary rays, form the bast ring. In addition to sieve tubes, cambiform cells, and parenchyma, the bast may contain oil cells, mucilage cells, latex tubes, and other elements. Starch is often present. Microscopic Elements of Barks. The elements of chief importance in diagnosis are bast fibers, stone cells, starch grains, and cork. The other elements have less striking characters. Wood. The wood elements, like the phloem elements, are in radial rows, separated by medullary rays, and also in annual layers. The ele- ments include vessels and tracheids of numerous types, wood fibers, parenchyma, and medullary parenchyma. The parenchyma cells often 42 PRELIMINARY. contain starch and calcium oxalate, and all the tissues may contain or be impregnated with resins, essential oils, etc. Woods are not used as foods, but sawdust and red sandalwood powder are common adulterants. u b c d e f g h i k I Fig. 25. Elements of a Dicotyledonous Fibro-vascular Bundle in longitudinal section, a parenchyma of pith; 6 annular vessel passing into spiral vessel; c spiral vessel; <£ reticu- lated vessel; e wood parenchyma; / wood fiber; g pitted vessel; ft wood parenchyma; i cambium layer; k cambiform cells; I sieve tubes; m sieve parenchsrma; n bast fibers; parenchyma. (Kny.) The Microscopic Characters of woods of angiosperms and gymnosperms as given by Moeller are as follows: The Wood of Angiosperms is characterized by the vessels with numerous small pits (Fig. 26, g). More abundant than these are the wood fibers (/) occurring mostly in bundles, accompanied often by wood parenchyma (/>), and crossed by medullary parenchyma {m). Simple crystals of calcium oxalate in crystal fibers occur in many tropical woods (Fig. 28, k). Determination of the species or even the genus by the characters of the powder is very difficult. Chief dependence must be placed on the structure of the vessels. The Wood of Gymnosperms consists in large part of tracheids with single rows of bordered pits (Fig. 27, t), which, except in the spring wood, where they occur sparingly, are on the sides adjoining the medullary rays. These are most striking in radial sections. Well-formed oxalate crystals MORPHOLOGY OF ORGANS. 43 are absent. The wood of certain European species may be distinguished by the characters of the medullary rays. Fig. 26. Sawdust of an Angiospermous Wood, p wood parenchyma; I wood fibers; g vessels with numerous pits; m medullary rays in radial and tangential view; K crystal cells. X 160. (MOELLER.) SUBTERRANEAN STEMS. To this class belong Rhizomes or root-stalks (e.g. ginger), Tubers (e.g. potato), and Corms (e.g. cyclamen). Rhizomes in common parlance Fig. 27. Sawdust of a Coniferous Wood, t tracheids with single rows of pits; m medul- lary rays; p parenchyma. X 160. (Moeller.) are classed with roots. Bulhs (e.g. onion) are subterranean stems covered with leaf scales. 44 PRELIMINARY. Many subterranean stems are reservoirs of starch, sugar, inulin, and other reserve materials, and are important foods. Their tissues are much A B -TO ,m Fig. 28. Red Sandalwood (Pterocarpus sanlalinus). A radial section; B tangential sec- tion, k crystal fibers; I wood fibers; p wood parenchyma; g bundle; m medullary rays. X 160. (Moellee.) simpler than those of aerial stems, consisting chiefly of parenchyma with a thin covering of cork and relatively few bundles. In the rhizomes of dicotyledons the bundles, hke those of aerial stems, are collateral ; in those of monocotyledons they start as collateral, but later often become con- centric, with the xylem encircling the phloem. Mechanical elements, being unnecessary, are usually few or entirely lacking. THE ROOT. The root fixes the plant in the soil and absorbs the water and mineral matters essential for life and growth. In certain plants the root is fleshy, serving as a storehouse for reserve material. The roots used as foods include the turnip, beet, carrot, parsnip, chicory, and others. Annual Root. The general structure resembles that of dicotyledonous stems, but the elements of the epidermis and the arrangement of the bundles are quite different. MORPHOLOGY OF ORGANS. 45 1. Epidermis. Root hairs, consisting of blunt, thin- walled outgrowths from the center of epidermal cells, are found on young roots. Hairs such as occur on aerial parts, as well as stomata, are never present. 2. Cortex. This is a parenchyma tissue similar to that of stems. Chlorophyl is absent. 3. The Endodermis is characterized by the suberized and often thickened walls. 4. Bundle Zone. The outer layer (pericycle or pericambium) is of parenchyma. The bundles proper are of the radial type the phloem and xylem being side by side, not one in front of the other, as in the collateral bundles. The groups of xylem and phloem elements alternating with one another form a chain about the center of the root. 5. Pith. This may or may not be evident. Certain fleshy annual roots, such as the beet, show concentric rings similar to those of wood. These are formed by a series of new cambium layers which appear one after another in the parenchyma, each producing a ring of phloem and xylem. Perennial (Woody) Roots. The secondary changes in the roots of monocotyledons are not impor- tant, but in dicotyledons the structure finally becomes much the same as that of the stem. The epidermis with root hairs is replaced by cork, and the bundles change from radial to collateral. The cambium forms out- side of the xylem and inside of the phloem of each bundle, and conse- quently is at first sinuous in cross section. As the thickening proceeds the radial arrangement disappears, and the cambium finally forms a ring like that of stems. BIBLIOGRAPHY. See p. 27. PART II. GRAIN: ITS PRODUCTS AND IMPURITIES. GRAIN. Grain, in the ordinary acceptance of the term, includes such fruits of the cereals {GraminecB) and buckwheats (Polygonacea) as are valuable as food for man and cattle. The impurities of grain include weed seeds, ergot, spores of smuts, straw, dirt, and other matters (p. 145 el seq.). Weed seeds belonging to the GraminecR and Polygonacece are described with the economic species of these families. The nature and purity of grain is readily determined by macroscopic examination, although a thorough understanding of the microscopic structure of the whole grain is essential for the diagnosis of products. Flour and Meal. In the examination of mill products with respect to their purity and wholesomeness, the following points call for consideration: (i) Is added mineral matter present? (2) Is it or has it been infested by insects or other forms of animal life ? (3) Has the product or the grain from which it was made been damaged by rusts, moulds, or bacteria? (4) Was it made from sprouted grain? (5) Are starch or tissues of weed seed present in appreciable amount ? (6) Are foreign flours or other vegetable adulter- ants present ? _ Mineral Adulterants. Calcium sulphate (gypsum), calcium carbonate (chalk), clay, and even sand were formerly added to flour and meal, but at the present time are seldom if ever used in any cereal product, although calcium sulphate in considerable amount has been frequently detected in cream of tartar and baking-powder, and powdered rock (talc and tremo- lite) to the extent of 25 per cent has been found in one brand of baking- powder examined at the Connecticut Experiment Station. Foreign mineral matter is best detected by determinations of ash, supplemented by an ash analysis, although the chloroform test (p. 53) furnishes valuable indications. 49 so GRAIN. Insect and other Animal Contamination. According to Chittenden ^ the insects which most commonly infest grain and flour are cosmopolitan, having been distributed by commerce to all quarters of the earth. The following common species are described : The granary-weevil (Calandra granaria L.), the rice-weevil {Calandra oryza L.), the Angoumois grain-moth {Sitotroga cerealella 01.), the wolf- moth {Tinea granella L.), the Mediterranean flour-moth (Ephestia Kueh- niella Zell.), the Indian (maize) meal moth (Plodia inter punctella Hbn.), the meal snout-moth (Pyralis jarinalis L.), the confused flour- beetle {Tribolium confusum Duv.), the rust-red flour-beetle (Tribolium jerrugi- neum Fab.), the slender-homed flour-beetle {Echocerus maxillosus Fab.), the broad-homed flour-beetle (Echocerus cornutus Fab.), the small-eyed flour-beetle {Palorus ratzeburgi Wissm.), the yellow meal-worm (Tenebrio molitor L.), the dark meal-worm (Tenebrio obscurus L.), the saw-toothed grain-beetle (Silvanus surinamensis L.), the red or square-necked grain- beetle (Cathartus gemallatus Duv.), the European grain-beetle (Cathartus advena Waltl.), and the cadelle (Tenebroides mauritanicus L.) Among the creatures found only in the ground products are the sugar- mite (Lapisma sacckarina), the common flour-mite (Acarus farina), and the feathered mite (Acarus plumiger). The figures and descriptions given by Chittenden, Bohmer,^ and other authors aid in the identification of the foregoing species. In cases where the live insects are no longer present evidences of previous infection are often furnished by the wings or other parts of dead insects, also by the excrement, webs and other remains, seen either with the naked eye or under the microscope. Wheat is often infested by the wheat- worm (TylenchusscandensSc\m., Anguillula tritici Need.) a nematode related to Trichina. So-called "cockle-wheat" (Fig. 29) consists of wheat kernels entirely transformed by the ravages of this disgusting, but probably harmless, creature. The more or less distorted kernels are from 3-7 mm. long, and often forked at the apex. The tough shell, consisting of rather thick- walled porous sclerenchyma elements with intercellular spaces, inclose a tangled mass of worms, which, as may be seen with a low power, become active when thrown into water. The worms are upward of i mm. long, pointed at ' Some insects injurious to stored grain. U. S. Dept. Agr. Farmer's Bulletin No. 45, Washington, 1896. ' Kraftf uttermittel, pp. 65-68. FLOUR AND MEAL. 51 both ends, and appear to be filled with a granular substance. They are easily recognized in water mounts. The Cryptogamic Plants which attack the inflorescence of cereals often render the grain unfit for flour-making. To this class belong the smuts (p. 165) and ergot (p. 164). Molds, yeast plants, algas and bacteria are also developed in the flour itself, especially after exposure to dampness, and as a consequence the n Fig. 29. Cockle \\'heat. / whole grains somewhat enlarged. II cross section: ep epidermis; p thick-walled parenchyma. (Vogl.) flour becomes "off color," lumpy, and offensive both in odor and taste. Fungus hyphae, spores and other ciyptogamic elements furnish microscopic evidence of such contamination. Bohmer ^ gives analytical keys and systematic descriptions for the identification of these and other microorganisms. Sprouted Grain. As a consequence of improper storage, grain some- times begins to sprout, and thus loses in a greater or less degree its value for flour-making. Under the microscope the starch grains have a char- acteristic appearance due to their partial solution by the diastatic ferments developed during germination. The concentric rings are unusually dis- ' Loc. cit. 52 GRAIN. tinct, and branching channels resembling burrows of worms occur in many of the grains (Fig. 30). Weed Seeds. See pp. 145-163. Foreign Flour. In Europe, wheat flour is sometimes adulterated with rye, barley, buckwheat, rice, bean, potato, or acorn flour, while in America it is frequently mixed with maize flour. Rye flour, according to the German authorities, is much oftener adul- terated by inferior wheat flour than wheat flour by rye flour. Buckwheat flour is often mixed with wheat, maize, barley, or rice Fio. 30. Starch Grains from Sprouted Cereals. Left, large grains from wheat; right, from rye. (X'OC.L.) flour, sometimes with the intent of cheapening the product; less often to meet the demands of consumers. Rice flour is liable to the same forms of adulteration as buckwheat flour, while maize flour, because of its cheapness, is seldom adulterated. Sawdust, Maize Cob, and other similar waste products cannot be reduced to a sufficiently fine powder to be used in fine flour, but are some- times mixed with coarse meal, and cattle foods. They are detected by their high percentage of crude fiber and low percentage of starch and protein, as well as by their characteristic tissues. Methods of Examination. Preliminary Examination. The color, odor, taste, and other physical characters should first be noted and compared with samples of known purity. Flour or meal that is damp, mouldy, foul-smelling, or infested by insects, is obviously unfit for food whatever may be the results of chemical or microscopic examination. Color Test. In German mills and custom-houses since 1894, the color of flour has been determined by "pekarizing" (pekarisircn) as follows :i ' Vereinbarungen zur einheitlichen Untersuchung u. Beurthcilung von Nahrungs- u. Genussmittel. Berlin II, 1899, iS. FLOUR y4ND ME/1L. S3 Spread two teaspoonfuls (15-20 grams) of the flour on a glass plate or thin board, so as to form a parallelopiped 5 cm. long, 3 cm. broad and 2 mm. high. Cover with a glass plate and press until the surface is smooth. In this way the color of different samples may be much more accurately compared than when loose. The differences in color are brought out still more strikingly by care- fully placing the plate in a sUghtly inclined position under water and keep- ing in that position for about one minute. Caillettefs Chloroform Test, designed chiefly to furnish indications of mineral adulteration, consists in shaking in a test-tube about 2 grams of the flour with 25 cc. of chloroform. If on standing, any considerable amount of deposit collects at the bottom of the tube, the presence of mineral matter is indicated, as the flour particles, being for the most part hghter than chloroform, rise to the surface. This residue may be examined chemically, but the test should always be corroborated by an accurate determination of ash in the original material and an analysis of the ash. Beneke's Chloroform Test} This test serves not only to detect mineral powders but also to distinguish rye flour from wheat flour, or to detect the presence of one in the other. It is as follows : Place 100 grams of the flour in a 500-600 cc. flask and add enough chloroform to fill the flask two thirds full; cork and shake carefully until no lumps remain; then fill nearly full, shake vigorously, and allow to stand. A brown deposit of dirt soon settles, and gradually a further deposit, consisting largely of aleu- rone cells forms a layer over the last. After about 24 hours, this latter deposit should be examined with the naked eye and under the microscope, noting especially the color. The aleurone cells of rye are blue or olive- green, those of wheat yellow-brown. VogVs Alcohol-Hydrochloric Acid Test^ furnishes indications of the presence of foreign flour or ground weed seed. Shake violently 2 grams of the flour in a test-tube with 10 cc. of a solu- tion containing 5 per cent of hydrochloric acid and 70 per cent of alcohol ; warm finally at a gentle heat and allow to settle. Note the color in reflected Ught of the column of solution, the meniscus, and the deposit. Wheat flour entirely free from impurities yields both a colorless solu- tion and a colorless deposit, and wheat flour with a small amount of im- ' Landw. Vers.-Stat. i88g, 36, 337. ' Die wichtigsten vegetabilischen Nahrungs- u. Genussmittcl, p. 24. 54 GRAIN. purity, also common rye, oat, and barley flour, yield a pale yellow or pale yellow-red solution. A decided coloration of the solution, particularly at the meniscus, indicates a considerable amount of weed seed. Cockle (Agroslemma) and darnel {Lolium) color the solution orange- yellow; leguminous seeds, rose-red, violet or purple; cow wheat {Melam- pyrum), blue-green or green; ergot, flesh-red to blood-red. Gluten Test. Make a handful of the flour into a dough with the smallest possible amount of water and wash with continual kneading imder a stream of water. Wheat flour yields by this treatment an elastic mass of gluten while the flour of other cereals is gradually but completely washed away. Chemical Examination. Determination of the usual proximate con- stituents in the flour often aids in the diagnosis. For example, wheat flour is moderately rich in protein but poor in fat, com flour is somewhat poorer than wheat flour in protein but much richer in fat, while buckwheat and rice flour are poor in both of these constituents. Microscopical Examination. In 1882, the Association of German Millers offered a prize of a thousand marks for an essay describing a simple process for detecting admixtures in wheat and rye flour. Wittmack won this prize, and the motto of his essay was : " Das Mikroskop ist der beste Leitstem." Not only is it true that the microscope is the most valuable means for the examination of flour, but in many cases it is the only means. The following methods of preparing the material for examination will be found useful: Direct Examination. The points of special importance are the size and shape of the starch grains, the presence or absence of aggregates, the size of the hilum, and the distinctness of the rings. With the aid of the key on p. 64 and the descriptions under each cereal identifica- tion of the group and often of the particular starch is readily accom- plished. Among the more difficult problems are the distinction of the grains of wheat, rye, and barley; of rice, oats, and darnel; and of maize and sorghum. Polarized light is useful in determining the locations and form of the hilum through which the crossed lines seen with crossed Nicols always pass. In cereal starches the hilum is central, and in potato and various other starches eccentric. The hilum of leguminous starches is elongated (see Fig. 572). The crossed lines differ greatly in intensity, being scarcely evident FLOUR AND MEAL. 55 in wheat, rye, and barley, but distinct in maize, sorghum, rice and many other kinds. The brilliancy of the starch grains and their crosses when viewed with polarized Ught also aids in detecting them in the presence of fat globules and aleurone grains, although the addition of iodine solution accomplishes the same end. Heating the water mount to boiling or Addition of Alkali (potassium or sodium hydrate) dissolves at once the starch and proteid matter and thus clears the tissues. Usually, however, this treatment, which is so valuable in the case of materials with considerable bran tissues, is of less service in the examination of flour than one of the following methods for accumulating the bran tissues from a large amount of the material. Schimper^s Scum Method.^ Mix thoroughly 3 grams of the flour with 100 cc. of water and heat without further stirring until the boiling- point is reached. The scum which rises to the surface contains the greater part of the hairs and other bran tissues, and may be transferred to a slide and examined both directly and after treating with chloral or alkali. Steinbusch's Diastase Method.^ Make 10 grams of the flour into a paste with 40 cc. of water and add with constant stirring 150 cc. of boiling water. Cool to 55°-6o° C. and add 30 cc. of malt extract (pre- pared by digesting at room temperature for 3 hours 1 part of freshly ground malt and 10 parts of water and filtering) and keep at 55°-6o° for 15-30 minutes. Dilute, allow to settle, decant off the Hquid, wash the residue once or twice by decantation, and finally treat with i per cent sodium hydrate. This method is more laborious than the two following methods and has no advantage except in the case of delicate tissues. If quantitative determinations of starch are made, the residue after the malt digestion may be used for microscopic examination. Hydrochloric-acid Method.^ Mix 5 grams of the flour in a casserole with 500 cc. water, heat to boiling, add 5 cc. concentrated hydrochloric acid and boil for 15 minutes. After allowing to settle, decant off the super- ' Schimper, Anleitung zur mikroskopischen Untersuchung der vegetabilischen Nahr- ungs- u. Genussmittel. Jena igoo, 17. = Ber. d. deutsch. Chem. Ges. 14, 2449. ' Various modifications of this method have been described by Moeller, Schimper, and other authors. 5 6 GRAIN. natant liquid and mount the deposit of bran elements either in water, chloral or dilute alkali. Lauck's Method ^ is the same as the crude-fiber method (p. 1 7) except that 2.5 per cent sodium hydrate is used and the solution is boiled but 5 minutes. The treatment dissolves completely the starch, proteids and fat, thus making the tissues very transparent, but it also distorts the hairs by swelling the walls, and for that reason is not suited for the detection of wheat flour in rye flour, or vice versa. Of the processes for accumulating and clearing the tissues, Schimper's scum method has the least action on the cell-walls, Steinbusch's diastase method somewhat more, the hydrochloric-acid method still more, while Lauck's method is most energetic of all. The methods are arranged according to the intensity of their action. Vogl's Naphthylene-hlue Method? Thoroughly mix 2 grams of the flour with a small quantity of a solution of o.i gram of naphthylene blue in a mixture of 100 cc. absolute alcohol and 400 cc. water. Transfer to a slide, allow to dry and examine in sassafras oil or some other essen- tial oil or else in creosote or guaiacol. After this treatment the pericarp coats and contents of the aleurone cells and germ tissues appear bright blue or violet-blue, and the walls of the aleurone cells light blue, while the tissues and contents of the starch cells remain colorless and are ren- dered transparent by the mounting medium. BamihVs Test (p. 70). BIBLIOGRAPHY. See Bibliography of Wheat. Bread. Bread, in the broad sense of the word, including biscuit, cakes and other cereal oven products, is made either from the flour of one cereal or of several cereals. It is raised commonly either with yeast, baking-powder (or an equivalent), or eggs. The examination of bread is much more difficult than that of flour, partly because other vegetable materials arc present, and partly because the starch grains of the flour are much distorted by baking. ' Vereinbaningen zur einheitlichen Untereuchung u. Beurtheilung von Nahnings- u. Genussmitteln. Berlin, Heft 11, 1899, 23. ' Die wicht. vegetab. Nahr.- u. Genussm. Berlin and Wien 1899, 17. BREAD. CATTLE FOODS. 57 The histological elements include the distorted starch grains (Fig. 31), more or less bran tissues, and if yeast was used as the leavening agent, cells of the yeast plant. Of the methods of examination described under ilour, the diastase method, the hydrochloric-acid method, and the crude fiber process, are Fig. 31. Starch Grains from Wheat Bread, a typical forms, little altered; 6 broken and swollen forms. (MoELLER.) also suited for the examination of bread, provided the material is first dried and ground to a moderate degree of fineness. Chemical examination includes determinations of the usual proximate constituents, tests for alum and other baking chemicals, and, in the case of highly colored products, tests for artificial color. Cattle Foods. Mill Products. The mill products of wheat, rye, barley, rice and buckwheat, are more commonly consumed by the human family, only the by-products being cheap enough for cattle foods. Among the most important mill products designed especially for cattle, are maize meal, ground oats, and provender (a mixture of maize meal and ground oats). Of lesser importance are meals made from the chaffy wheats, sorghum, millet, and other cereals. These products are much coarser than flour designed for human use, and are invariably prepared from the whole kernel without separation of the bran or adhering chaff. Mill By-products include the offals of flour mills, breakfast-food factories and some other industries. Among the most important materials are screenings, bran, and middlings, from wheat, rye, barley, maize, buck- wheat, and rice, also more or less analogous materials designated by special 58 GRAIN. names, such as hominy feed, oat feed, etc. These products, with the excep- tion of screenings, which is treated in a separate chapter (pp. 145, 163), are described under the different cereals. All of these materials contain starch grains in their original form. By-products from the Manufacture of Starch and Glucose. In Europe starch and glucose are made chiefly from wheat or potatoes, in the United States almost exclusively from maize. In the American factories, whether starch or glucose is the final product, the germ is first separated from the remainder of the grain and subjected to pressure to remove the oil. The oil-cake is similar to the cake of true oil seeds in that it contains no starch, but a high percentage of pro- teid and a considerable amount of residual oil. Starch is separated mechanically from the remainder of the grain in a wet way and is purified for cooking and laundry purposes, or is con- verted by acid into glucose. The dried residues from the processes are known as gluten meal, gluten feed, starch feed, etc. (p. 96). As they are dried at a rather high temperature the starch grains are distorted or entirely disorganized. Brewery and Distillery By-products include malt sprouts, brewery grains and distillery grains. Malt sprouts are the worm-like radicles removed from sprouted barley. They are quite simple in structure, and contain no starch in any form fp. 86). Malt and distilled liquors may be made from any of the cereals. In Europe barley, rye and wheat are chiefly employed; in the United States, barley, rye and maize; in Japan, China, and India, rice and to some extent sorghum. As the starch originally present in the grain is converted successively into sugar and alcohol, the residue or "grains" contain no appreciable amount of starch. Both wet and dry grains are used for feeding. Chaff of oats, barley, rice, and weed seeds, also maize cob and buck- wheat hulls, although of httle value except for packing or fuel, are used for cattle foods, especially when mixed with more valuable material. Oat and barley hulls are obtained in the factories where oatmeal and pearl barley are made and are ingredients of certain proprietary cattle foods containing, in addition to cereal constituents, some concentrated food, such as cottonseed meal or linseed meal. Rice hulls, maize cob, peanut shells, and coffee hulls, notwithstanding their lack of valuable nutrients and their harsh woody structure, are not infrequently met with in cattle foods, especially as adulterants of bran. CATTLE FOODS. S9 Methods of Examination. Preliminary Examination. The material should first be spread out on a paper and fragments of a suspicious nature picked out with forceps. This search is usually facilitated by separating the material by means of a series of sieves into several portions of different degrees of fineness. Many times impurities, such as chaff, insect remains, mouse excrement, etc., may be identified with the naked eye or under a lens, although more often positive identification is not possible without recourse to the microscope. In bran the black hulls of cockle or of black bindweed are often present, the former being characterized by the rough outer surface, the latter by the smooth but dull surface and the regular shape of the larger fragments. Foxtail (Seiaria) is recognized by the mottled color and the transverse wrinkles on the flowering glumes and other weed seeds by the characters learned from the descriptions, as well as by comparison with standard specimens. Rice hulls or chaff, even in quite small pieces, are recognized under a lens by their rough surface and straw-yellow color; oat hulls by the smooth convex surface; barley hulls by their smooth but ribbed surface; corn- cob by the hard fragments of the woody zone and the hard glumes, also by the papery thin glumes, often of a red color. The bran coats of wheat and rye are rather soft, of a reddish or buff color; those of maize tough and homy, either white, yellow or red (rarely blue) ; those of oats and rice, thin and delicate, of a brownish-yellow color. These are but a few of the macroscopic characters which either furnish positive evidence, or serve as a guide for microscopic examinations. The eye of the microscopist as well as his senses of taste, smell, and touch soon becomes trained to note very shght pecuharities, which often leads him to form an opinion before he has looked in his microscope. The Chemical Analysis of fodders commonly includes the determina- tion of water, ash, protein (NxdJ), crude fiber, nitrogen-free extract (by difference) and fat. Determinations of starch, sugars, pentosans and albuminoid nitrogen are rarely desirable. Microscopic Examination. As the cereal products and by-products used for cattle food are for the most part coarsely ground, and contain considerable amounts of the bran coats or chaff, their identification is usually easier than that of flour and other products consisting largely of starchy matter in the form of a fine powder. Direct Examination. For the identification of starch grains an ex- 6o GRAIN. amination is made in water either of the fine powder separated from the coarse by sifting, or of a finelytround sample of the wtiole material: Coarse fragments of a starchy nature picked out with the forceps arc crushed, scraped or sectioned and likewise examined in water. Exami- nation AVitH the aid of polarizing apparatus is often useful. Treatment with Reagents. Fragments of bran or chaff may also be examined directly in water, but much better results are secured after first dissolving the starch and other interfering substances, either by boiling for a moment in water on the slide (always under a cover-glass), or by mounting in dilute alkah or in chloral hydrate. It is often convenient to examine the finely-ground material or iso- lated fragments, first in cold water, then after treatment with a small drop of iodine tincture, again after boiling, and still again after treatment with a small drop of 5 per cent potash or soda solution. Crude-fiber Process. As most cattle foods contain a considerable amount of the bran coats and other tissues, there is commonly no need of resorting to the methods described under flour, as a means of accumu- lating the tissues from a rather large quantity of the material, although as a means of clearing the tissues, some of these methods, particularly Lauck's method, or what is practically the same thing, the crude-fiber process, are occasionally useful. After weighing the fiber a portion obtained in the quantitative determination of crude fiber may be used for microscopic examination, as the subsequent determination of ash in this fiber is not appreciably affected by the removal of the small quan- tity necessary for the purpose. CEREALS {Graminece^. Most grasses are hermaphrodite, the organs essential to fertilization being in the same blossom, although in some blossoms either the male or female element is abortive. Maize is, however, monoecious, the flowers of the tassels being entirely male, those of the ear entirely female. The inflorescence is in panicles, racemes, or spikes, made up of spike- lets (Fig. 32, A), each consisting of two lower scales {empty glumes) on opposite sides of the axis, and one or more flowers (5), each usuallv inclosed by two scales, the one {flowering glume) situated on the outer side, the other {palet) two-veined and two-keeled, situated on the inner side with its back toward the axis. Sometimes the flower is CEREALS. 01 inclosed by only one scale, in which case it is the palet that is lacking. Two minute hyaline scales {lodicules) are commonly present at the base of the flower and rarely a third occurs within the palet. The beard