5 Saar rea Pe ee ake cannes Raat THIS BOOK |S THE GIFT OF ae es ‘Surkingharm, N asnion gt ox a at XA : ee Digitized by Microsoft® UT P08 Digitized by Microsoft® This book was digitized by Microsoft Corporation in cooperation with Cornell University Libraries, 2007. You may use and print this copy in limited quantity for your personal purposes, but may not distribute or provide access to it (or modified or partial versions of it) for revenue-generating or other commercial purposes. Digitized by Microsoft® Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archiye.org/details/¢u31924051101008 iCros Digitized by Microsoft® HOW CROPS GROW. A TREATISE ON THE é CHEMICAL COMPOSITION, STRUCTURE, AND LIFE OF THE PLANT, FOR ALL STUDENTS OF AGRICULTURE. WITH NUMEROUS ILLUSTRATIONS AND TABLES OF ANALYSES. BY SAMUEL W. JOHNSON, M. A., PROFESSOR OF ANALYTIOAL AND AGRICULTURAL CHEMISTRY IN THE SHEFFIELD SCLENTIFIO SCHOOL OF YALE COLLEGE; OHEMIST TO THE CONNEC- TIOUT STATE AGRICULTURAL SOCIETY; MEMBER OF THE NATIONAL ACADEMY OF SCIENCES, NEW YORK: ORANGE JUDD & COMPANY, 245 BROADWAY. LL, Digitized by Microsoft® Entered according to Act of Congress, in the year 1868, by ORANGE JUDD & CO., At the Clerk’s Office of the District Court of the United States for the Southern District of New-York, Lovresoy, Son & Co., ELEctrroryrers & STEREOTYPERS, 15 Vandewater Street, N. ¥. Digitized by Microsoft® PREFACE. —+ For the last twelve years it has been the duty of the writer to pronounce a course of lectures annually upon Agricultural Chemistry and Physiology to a class in the Scientific School of Yale College. This volume is a result of studies undertaken in preparing these lectures. It is intended to be one of a series that shall cover the whole subject of the applications of Chemical and Physiological ' Science to Agriculture, and is offered to the public in the hope that it will supply a deficiency that has long existed in English literature. The progress of these branches of science during recent years has been very great. Thanks to the activity of numerous English, French, and especially German inves- tigators, Agricultural Chemistry has ceased to be the monopoly of speculative minds, and is well based on a foundation of hard work in the study of facts and first principles. Vegetable Physiology has likewise made re- markable advances, has disencumbered itself of many useless accumulations, and has achieved much that is of direct bearing on the art of cultivation. The author has endeavored in this work to lay out a groundwork of facts sufficiently complete to reflect a true and well-proportioned image of the nature and needs of the plant, and to serve the student of agriculture for thoroughly preparing himself to comprehend the whole 3 ; Digitized by Microsoft® Iv HOW CROPS GROW. subject of vegetable nutrition, and to estimate accurately how and to what extent the crop depends upon the at- mosphere on the one hand, and the soil on the other, for the elements of its growth. It has been sought to present the subject inductively, to collate and compare, as far as possible, all the facts, and so to describe and discuss the methods of investigation that the conclusions given shall not rest on any individual authority, but that the student may be able to judge him- self of their validity and importance. In many cases ful- ness of detail has been employed, from a conviction that an acquaintance with the sources of information, and with the processes by which a problem is attacked and truth ar- rived at, is a necessary part of the education of those who are hereafter to be of service in the advancement of agri- culture. The Agricultural Schools that are coming into operation should do more than instruct in the general re- sults of Agricultural Science. They should teach the subject so thoroughly that the learner may comprehend at once the deficiencies and the possibilities of our knowl- edge. Thus we may hope that a company of capable in- vestigators may be raised up, from whose efforts the science and the art may receive new and continual im- pulses. In preparing the ensuing pages the writer has kept his eye steadily fixed upon the practical aspects of the subject. A multitude of interesting details have been omitted for the sake of coniprising within a reasonable space that informa- tion which may most immediately serve the agriculturist. It must not, however, be forgotten, that a valuable principle is often arrived at from the study of facts, which, consid- ered singly, have no visible connection with a practical result, Statements are made which may appear far more curious than useful, and that have, at present, a simply speculative interest, no mode being apparent by which the farmer can increase his crops or diminish his labors by help Digitized by Microsoft® PREFACE, Vv of his acquaintance with them. Such facts are not, how- ever, for this reason to be ignored or refused a place in our treatise, nor do they render our book less practical or less valuable. It is just such curious and seemingly useless facts that are often the seeds of vast advances in industry and arts. For those who have not enjoyed the advantages of the schools, the author has sought to unfold his subjects by such regular and simple steps, that any one may easily master them. It has also been attempted to adapt the work in form and contents to the wants of the class-room by a strictly systematic arrangement of topics, and by di- vision of the matter into convenient paragraphs. To aid the student who has access toa chemical labor- atory and desires to make himself practically familiar with the elements and compounds that exist in plants, a number of simple experiments are described somewhat in detail. The repetition of these will be found extremely useful by giving the learner an opportunity of sharpening his perceptive powers, as well as of deepening the impres- sions of study. The author has endeavored to make this volume com- plete in itself, and for that purpose has introduced a short section on The Food of the Plant. In the succeeding vol- ume, which is nearly ready for the printer, to be entitled “How Crops Feed,” this subject will be amplified in all its details, and the atmosphere and the soil will be fully discussed in their manifold Relations to the Plant. A third volume, it is hoped, will be prepared at an early day upon Cultivation ; or, the Improvement of the Soil and the Crop by Tillage and Manures. Lastly, if time and strength do not fuil, a fourth work on Stock Feeding and Dairy Produce, considered from the point of view of chemical and physiological science, may finish the series. It is a source of deep and continual regret to the writer that his efforts in the ficld of agriculture have been mostly Digitized by Microsoft® VI HOW CROPS GROW. confined to editing and communicating the results of the labors of others. He will not call it a misfortune that other duties of life and of his professional position have fully employed his time and his energies, but the fact is his apology for be- ing a middle man and not a producer of the priceless com- modities of science. He hopes yet that circumstances may put it in his power to give his undivided attention to the experimental solution of numerous problems which now perplex both the philosopher and the farmer; and he would earnestly invite young men reared in familiarity with the occupations of the farm, who are conscious of the power of investigation, to enter the fields of Agricul- tural Science, now white with a harvest for which the reapers are all too few. Digitized by Microsoft® “ACKNOWLEDGMENTS. The author would express his thanks to his friend Dr. Peter Collier, Professor of Chemistry in the University of Vermont, for a large share of the calculations and re- ductions required for the Tables pp. 150-6. Of the illustrations, fig’s 3, 4, 5, '7, 47, 63, and 64, were drawn by Mr. Lockwood Sanford, the engraver. For oth- ers, acknowledgments are due to the following authors, from whose works they have been borrowed, viz. : ScHLEIDEN.—Fig’s 10, 13, 17, 19, 30, 48, 49, and 50, Physiologie der Pflanzen und Thiere. Sacus.—Fig’s 56 and 65, Sitzwngsberichte der Wiener Akademie, XX XVII, 1859, and fic’s 22, 38, 40, 41, 42, 43, 59, 66, 69, 70, and 71, Haperimental-Physiologie der Pflanzen. Pavren.—Fig’s 11, 12, and 23, Precis de Chimie Indus- trielle. Ducuartre.—TFig’s 60 and 61, Lléments de Botanique. Ktun. — Fig’s 18, 21a, 29, and 34, Erndhrung des Rindviehes. Hartic.—Fig’s 20, 21b, 32, Entwickelungsgeschichte des Pflanzenkeims, Unerr.—Fig. 26, Sitzungsberichte der Wiener Akade- mie, XLII, and fig. 55, Anat. u. Phys. der Pflanzen. Scoacut.—Fie’s 33, 37, 44, Anatomie der Geweschse, fig’s 51, 53, 54, and. 62, Der Bawm, and fig’s 52, 57, and 58, Die Kartoffel und thre Krankheiten. Henrrry.—Fig’s 86 and 39, Jour. Roy. Ag. Soc. of Hingland, Vol. XTX, pp. 488 and 484, ve Digitized by Microsoft® TABLE OF CONTENTS. ENTRODUOTION cicad ci siaausedinaiadduacdise smtarare occen sia maas Te Ret ere <3 DIVISION I.—CHEMICAL COMPOSITION OF THE PLANT. Cap. I.—THE VOLATILE PART OF PLANTS......+---eeeeeeees sists ae Jeowseins (28 § 1. Distinctions and Definitions... . 28 § 2. Elements of the Volatile Part of Plants. Carbon, Hydrogen, Oxygen, Nitrogen, Sulphur, Phosphor- 4 us, Ultimate Composition of Organic Matter............. 3. Chemical AMADIUY 55 cecvccsence, seca one oros sa meade eee aoe 46 4. ea lige Organic Compounds or Proximate Elements....... a D,WaAters cciisis;: sa deseeeeaeneseses aaweeaeas ataistsinie ave prcsslgisis 5 2. ehalons GROUP es nssi er saraewes oases seas eessins telesales 55 3. Pectose aeeer aissSja/digre alee srea tie VMs aaNe aie disies 81 4. aeeeule AGIOS. nc sncaiccsuinsise ceethsis Sen sencung seam 85 De. RATS 56 s:4: “aisiaiaigio:a nw nin seiovese)a(e sinsewiaieie’ei stestion OD 6. Albuiiinoid Sy wise sic esa aye: ays fate evens aS an f0im aegigier ek ppendix, Chlorophyll, OU Civice:s.aracaie oialarnie deaesen ecole lection coeieds 109 Cuap, I.—TsE ASH OF PLANTS.........0cceeee cece erences ovesvecodd L §1. Trerements of the Ash. carataig Wie aise i 111 Non-metallic Elements............--...-0+6+ osteo Carbon and its Compo aise tari lale ay she .. 113 Sulphur Be pad S eralnavearaiiyy .114 Phosphorus ‘+ ‘* ae . ee 1 Silicon sey ae se 119 Metallic Elements................ 123 Potassium and its Compoun' 124 Sodium 124 Calcium eee wee ee 125 Magnesium and its Compound 126 Tron «127 Manganese “ “ “LL eee ee +128 SAMOS ies biases a scinsins gaiagiginianina 08 oo @asulnese oo eeniensen sae 129 Cardonates., tanesca siwseers sxemense rere seueess 130 Sulphates cc. siscsawas vemsece nee cocinenses vaiovie -132 Pospoates: Radia anatase Mee area oe ne SAREE SERS -133 Chlorides... 135 NU EPR CS 5. ister ciacsisiecsis Tosiaungbnranv’cl= .136 § 2. Quantity, Distribution, and Variations of the Ash.. +138 Table of Proportions of Ash in Vegetable Matter....... 139 § 3. Special Composition of the Ash of an Plants... . Constant Sec uaee ee mo WH Qa so . 3 ss ° B &. fae, ° a x] AVEMIDS vasatecisas ‘* Function of. -.. 197 | Azote. MAO: BALI Es, cnesifoted aiatesparee ced = 26) Alum, decomposed by diffusion... 364 ML ee eee - 380 Pee Slater acsed ia ysl cacia huis’ acd cia tah 129 | Barley, Focnpets Gnu .150, 153, 160, 37S minum. ay roxi B87 Pe aoaTRCer ot a roximate analyses ea diaein serrectt S87 Root-cap of... clio ncaa ; ” " Toccaue of. ' arley-Sugar......... Amyloids 4 Baryta in ‘plants. 22 Transformation of........ %8 | Bases, Definition of. Anhydrous phosphoric acid........ 117 | Bassorin.. ais ae BILICIC ACID: ss sieaienarecaie 5 Digitized by Microsoft® INDEX. xT Bicarbonate of potash. eieaivratein ’ Bicarbonate of soda............ Biennial plants...... dat eicie 251 Bitartrate of potash................ 88 plestings of vine..... +250, oe Blight......... Blood-fibrin. Bone-black.. Bons-phosphate Bread grains, Detailed analyses... 388 Bretschneider, Study of oat-plant.. os Bromine.... PWG jineces medias exdeodaaetaaae iat Buds, Structure of. Bulbs. Development under pressur ae 26 ffein ie Caffeotanic acid .............06 - 110 Caleim issssmae esos) tases soneants 125 CAN GOB) sivisis:siecicicinyy sie eieiviesaicieiees 342 CAL yi a isssioaiarecoise:¢ siaraietasaunto,eipPiatcaere’s) ea 292 Cambium . 2271, 272, 276, a Cane SULB sve cccs cavecnes rescence Capillary attraction.........2. 0.065 319 Cara el ve cisys scr states arestyeiers sareraate 3 Carbon, Properties of............+- 31 Heo Uns able sasidanaes Yacie sa ee 2 113 Carbotlate ses 2c ciciesies sesnecws sacnece 130 Carbonate of lime.............6.5-. 131 Me potash........e...00ee 130 oe SHBOGH si6'sigcaeusielars Fsewseins 131 Carbonic CLG sencictars sata eid oid tcajary pieieets 113 ‘* as food of plant..... 328 AG ‘* in ash-analyses....... 149 Garbonization..........0+0ece sees 32 Carrot, Ash-analyses....... 155, 156, 3877 Casein... 100 Cassava .. soda... Canto tree.. Cell-contents. . ‘“* membrane, Thickening of,. se multiplication. lacsearate crastaisiven ge ‘* Structure of.. iad Cells, alee ote “Size Cellular lenis “ tissue.. Cellulose. Cellulose, ‘oe eae tishaaletes 60 Estimation.. a 9G MOSCsseorennassaeeece seins sowess 364, Chemical combination.. st decomposition... Chemistry.............66- CHOPPY? BUM s.-aonsiieis susrersinas Chlorhydric acid.. CHILOVIGES saci cocces eee dicucs s'56 Chloride of ammonium, decompos- OG: DY PAD be. sicisissoisns odin se oe 171 Chloride of Magnesium oe °° Potassium. Saja e way se ** Sodium. . ‘ Chlorine.......... ‘* essential to crops? ‘© function in plant... ‘© in strand plants Chlor rophyll.. req sissb a eeevass Church, on apeciie yrs of seeds. ue Circulation of BAD, spade tianenaion CUTIC ACL vice ss:a.-csieis.oies ogrermiatensioe gikcbys 33 Clr ates iss is caetns ac se wegecedsicoe 136 Classes. 3. masanaucamddisubaretaoe 298 Classification........ ......55 + 298 Clover, Ash Of............ce eee eeee 376 “« “soluble and insoluble ash-in- CCLCMU Be bccice ined baveinaeaoeeiete 194 Clover, washed by rain... Coagulation........... ceeeeseeeees BUA csccsiciste oesiviosiann ag Heese ee 87 Colloids..... vee 802 Combustion... . 35 Common Salt.. ++. 136 Composite plants Ldaiolebinyays Si stetaueta gree 300 Concentration of plant-food.. eure Concretions in plant............... 190 Coniferous plants... eee B00 Copper in maria 129, 196 CORK 5 scistsargcres 276, 277 COrM-Stareh s.« siesisrceisisiws wad. cise oe 00 63 Corolla. cceseade sascaawes ons saesiaeen 292 Cotton, ash-analyses..............- 156 fiber, fig.... 1, 22 “seed cal Cotyledon. ... is, 303 Crops, compos: Coniferous plants... Crude celluloge.. Cryptogams..... Crystalloid aleurone 0% Crystalloids......... aed Crystals in plant... 190, 192 Cubic centimeter..............e eee 58 CUIDIBS ce scpdisie yaad eeue-sanindeneei 262 CYAN Gs hairs dicag ah niedynaina Moknedeeiaie 114 CYON0SON ass aiaauen cadena nese 14 Digitized by Microsoft® XII Cyanophyll,.......e cece eee eee Pree 9) Darwin on insect-fertilization......295 ‘©. Hypothesis of.......... Decimal system of weights. Deflagration. ae Definite Proportions, Law of... ... 47 Deliquescent......... 0.00008 ceeeee 135 Density of seeds.. : Depth of sowing. 816 Dextrin.. . 69 Diastase.. 32 Dicalcic phosphate... 134 Dicotyledonous seed: Diffusion of names Diffusion-rates.. 352 Dicecious plants. ee 294 Direction of growth. 870 Disodic phosphate... 134 Double flowers ASUTYA siecopsis aia tratencreiearere Savamiateearse es Elements of Matter. Elm roots.. Embryo.. Emulsin.. Endogens.......... Endogenous plants Endosmose....... Endosperm .. Epidermis........ eo of leaf. : HQuisetam..ec0ss 02g sve genesene Equivalent replacement of bases. ..201 Eremacausis. Estimation of Albuminoids. Cellulose. eS Sugar. 6 Se “Water . 54 Etherial oils...................0006 90 Excretion of mineral matters from JONES. xis airs Cemmtermn ees 192 Excretions from roots. ... ........ 5 Exogenous plants Exogens Aeon apeecs Experiment-Stations of Germany... 24 Extension of roots. Extractive Matters.. Exudation of ash-ingr iS. Eyes of potato....... srpaspsdeyiciate Families....... Pi. acids. . Ferments . Fertilization. . FUDGE anisms sees meueanna HOW CROPS GROW. Fiber in oat crop. 210, a Fibrin... . .ccc ete cess pee sceenes Field-beet, ash- 55, 176. ant a SS... SDE eee BOE Flax fiber, fig..... -.. 56, 227 Flesh fibrin.. Fleshy roots.. Flower....... 291 Flow Of sap.... 2.20. seeeeeseeee eens Fluorine in plants soins 119, 195 Fodder plants, Ash of. pre) Foliage, Offices Of....-...+..++20++- 290 ee white in absence of iron. .199 Food of Plant. . + B27 Force... 25 IP ORC ES eawiaecasieaos 26 Formative layer.. Formulas, Chemical. Fructification Tructose....... 13 FRU ois! Secasis 300 Fruits, Ash Oh ee 379 oe * Composition of. Fruit sugar.... ....... Fuchsia, fig. of flower. wa BUN Chess srcrcronsaqe a seinen nial nyeieaeacierd 223 Gases, how pris buted throughout the plan Bee Gallic acid......... Gallotannic acid.... Gelatinous Silica. Genus; Genera.. 98 Germ........... - B02 310 Conditions of.......... 312 re Chemic’l Physiology of.318 311 ts Phenomena of......... Temperature ob saeeees 312 Girdlin gies x secede vanes 344 Glass .. 121 Glauber’s Sa. 132 Gliadin ..... 101 Globulin. . 2 OT GIN COSC iis cathe cua trette ceieAe zine Th Glucosides.. 7%, 110 Gluten...... .. 99 Gluten-Casein. -100 Glycerin... - 93 Gourd fruits. Downward and upward Gum, Amount of, in plants......... Gum Arabic..... ees. eee ae Gum Tragacanth.. Gun Cotton. . GY PSII si crizsod-oieuaseracarn eed Gyde, Exp. on root-excretion.. i Haberlan t, on Vitality of secds. ...306 Hemoglobin......... 0.0.0.0 cl 97 Hallett’s pedigree wheat............ 144 Digitized by Microsoft® INDEX, Hallier, Exp’s on absorption of pig- ments by Piso Bi Hazel leaves, oss by solution Heavy metal Henrici’s Exp. Herbaceous stems Honey-dew........csccceeee neces 6 Hooibrenk, artificial fecundation, | .295 Horse- chestnut, Ash-analyses of....159 Hybrid, Hybridizing sia Riais evans ale Gaaess 295 Hydrated phosphoric ic acid Sk BUTCH ccotscesaanpveinetee oo ee sulphuric acid........ Hydrate OL UMES:. c. asia sccieses $8. F8 MAONESIO ieee nee se AE potash siesta ns ee-eterers Hydration of membranes..... Hydrochloric acid............ Hydrogen aE in Germination.. IMbIiDItion. .. sce ee ese Imbibing power, Imbricated..... Introduction................5 Inorganic matter.... ........ Intercellular spaces JMterMOUeR ces o saa vemes crassa ee Iodine in plants. Solution Jerusalem Artichoke, Cell of. Juices of the Plant........ .. Kernel ess cssansaies svar Lactose..... Latent buds Laurus Canariensis, Air-roots of.. WATT oo is cies boaters ayece’sioce aipyeisivreia mares apa plants Mehatceuabuinties Leaf-gr ee “of trees, Ash ce “* under artificial pressure... .369 TCWG css scaicievajoiss eins eratessonta ere eitasieue eae 301 Legumin 101 Leguminous plants Legumes, ash-analyses... 152, 157, 379 se POR oe a cocctecoes oieigmate Lencopay Ml esaccae ns saccatracatciesersrsie 110 Levulose 13 Liebig on small seeds..........-... 308 “ " * relations between N and Pig! O1F io aoiasa a aeieg ga eeramyere Leis 202 Light, effect on direction of growth.375 ey ee Pate ones . 814 Light seeds, Plants from.. Lignin 00.0... cee ceeeee tenner necees DAM Cs nyesrasnenaiine oa esa veisieig Laevenaie ‘essential to vegetation ....... 172 LiMG- Water... eiisicsckons yok ceses 5 126 Hin olen ss cswaessicseiean’ ais aeae 90 Liquid Diffusion. Lithia, Lithium. “in ae Litter, Ash: Of... ccs ccs -.00s Londet, on witli of seeds... Madder CLOP eines esis fd biaoasonstees Magazine, Root as,........... Magnetic oxide of iron....... Magnesia 385d SIRs Balas oes aNGRANS mu _ Movements of, in oat.. a “Tare Section of... a stalls, be we Malizena-.32: cexexeavdeeere someueiads Malates..... a Malate of lime. “re Malic acid............ Malt, Cheaistie al of.. Maltose Ware Matter.. Meadow Medullary rays. Membrane-diffusio: Membranes, Influen on OF JUICER esis naeed es sees eae Metalic... sisicicie ‘ Metapectic acid. Metarabic Bats : Milk ducts.. Millon’s test... Moicaule: Weightsi.s..cncaessscsns 48 Moleenlesiciu.c.ces 48 Moneecious plants..............+65- 294 Monocotyledonous seeds........... 303 Monocalcic phosphate.............. 134 Motion caused by adhesion... ....350 MOU dsc jesse sic cinsgenhe ti4ges wee dares 223, Mucidin........... 101, 321 Multiple Proportions,.............- Mummy wheat... ...c cece ceeeeee Muriate of soda. Mustard, aie hairs Of........04065 244 MYyCOSC sass « Myristin... Nasiurtium, “Cells Of... csc cceccsaes 227 WNICOUD cece oi tects ssideca- sie 110 Niter, nitrate of potash............ 36 Nitrates in plants 105, 186 Nitrocellulose.. ig Nitrogen, Prop in ash.. pal “ Germi re relation to phosphoric AO Meas riuayeliaea Eadie enieesaapisisie 3 Digitized by Microsoft® xIV Nobbe & Siegert, Exp. on buck- 188 Non-Metal 112 Norton’s eae of oat-plant..141, 204 Notation, oe Spagalefeps cis dpateceseysveiais 49 Nucleus... asatevidrs 5 Nucleolus.. 300 Nutrieat mattersin plant, Motion of. ne Nutrition ep seedling ‘ Sf prox. ** ia +h “ee ‘* crop, weight per acre.. 222.387 ss at Composition and growth ara (ae audi gfatalnteincsieln cfc 7, 214, 217 Oat, onion of ash in its differ- ent PATHS revssesovesire ass in-Stercnchaysyars 4.Gbore 141 Oats, weight per bushel. ; ffices of organs of plant Oil in seeds, rete Organic matter. Organism..... Organs. . Osmometer . Ovaries.. Ovules.... Oxalates Oxalate of ammonia. we ** ** essential to plants. ss « ¢ State of, in Poe “ * manganese in ash.. QORADCS) ccicase sisinre eddie ec esaserntees ‘* of iron, described............ 127 CP Ee manganese, described... .128 Oxygen, Properties of.............. 33 “ oceurrence in ash......... 113 ‘¢ in Assimilation............ 326 “ ** Germination...G | 968) 68 | OF | 9S 198 | OOF] r : BOPZOW ” 8 ” OT | LG 88 | WL] $0 | ST | 8F ae Geo | Ls BIOM Aq T puv ‘qyooy-zpnyos Aq ” Lu oy gg |s'0 ee | Ust] 40 | PT [oe | FO | 199] Th ‘sosA[vay 6g Jo osvIoaVl| L's | OT OL 1Ssrloo 1FG 19h TYE 16091 °° ‘URC OL OLVLOd “adoge papnpour jou Srarjzoqy Aq stsdyouy pio|| 0 | e IE] ss | o-et | Fs | oes | OL | 9'ET | O'eT | °° y o oe JSOUSTH]| GEL | OEE] OL | CFE] OB | LSS] O'OT | SSS | SSG | SL “sasA(VUY 6 UL aovjuooI1ed JsaMo0T!! 0'0 oT oo |21°0 | 90 | v6 | e's GOT | Ps T9 “m0s5O sp AVM ., ” g ” SL | 9D Le jhe | TL | ews] ug | Ver} ewe] rye ‘doug oyLy Aq . 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YsD oo, | Danes etnyd|a2coyd BUT | DpOs | fo UN) ange | sou (PPO boy OL 199 er [penrq09 I-D.LA ‘SLONGOUd ANY SLINVTd TVUALTAOIYSV ANOS AO HSV AHL AO NOILISOdIOO d by Microsoft® igitize THE ASH OF PLANTS, ia JSOUSTH|| 9'F | 8°9 TOE) #9 | 9T | SIL] ost | Ges | Les | ste ‘soskiouy put aSuyroo10d ySoMOT|] TG | PT 6h | LP }So |} ’s | as | vst] o6 | ore BOM Aq stsdteay]} T¢ | 979 | Lor] og | OL | Sir] eer | Ter | wee | sre ‘wosso yAeM sq, og ” STS} Ts | so | Ss jor | se | se | oes] oe | or ‘sosd[eay F Jo osvzaay|| O'LT | ere Gu | Pa ek 186 | FOES SOs l Teel "SdOL LAGA ATIAIA 61 » SOUSTH|| SSE] O'S | CLT] GOT | St | sor] Fo | gos | ees] COs "a 20qItD jo aATSn[oxo soskjeny 6E UL aseyuodI0d ysoMoT]] oT | 00 96 |89 |00 | oS | LT | 00 | g'98 |] 09 Pstoyjo ,, ” G ” OL | OT 9 | FOF] FO | GET] OS | Ge 9°09 | ok “VOCED 35 ” To ” Tg | 00 PO} s6 | 00 |S erp art | ro Les | 69 “W0jssO FY AVAA ,, ” H) ” Vg 106 LPL] SIL] GO | SL) oe | Ler] ese | on ‘uOsIOpUy ,, an G ‘iy ¢9 160 Ter] @ or; 80 | OO) Lh | Fer} Aer] SIE srapunad Aq ” 9 7 oe | OT PIL| SPE | Ot | 06 | FR | 96 GOOF | SOT ‘sosdeuy gp Jo osuraay]] 19 | 40 SOE | OOF | FO TORI 9S 148 OSPiTs “LOOW dINadagL IWOUSTH|| FO | Ob WIL] OST | O'’ | GOT] Te | ste | 6:09 | GOL Seana ul oSeyuoor1ad PoOMOT!] T'S | 60 ee | 68 | 00 | 99 | St | Tor] our] 1¢ 4'S19q]}0 4, ” Z ” OF | Gs 8g | Ter} 90 | OIL] 9'¢ | OTe | Oss | e's ‘m0jssQ FY AAA Sq 8 Sr | PT GL | SOT] St | LOL] 8h | P08 | Teg | 9°9 “sosk[vay ar poostiaayl| 6% los | e9 letlor |oorles | Loe ou | on ‘LOOM LOWUVO eL qsousin]| sre | 9°6 | eer] er] te | sos | ter | eee | e769 er ‘sosdpeuy a Ul aSvjusorod 4ySaMOT!] O'S | 30 T@ | 6T 100 | 8s | Ts | se | oes} ose x S1IYIO ,, ” Bi s OL | T'S oP | Ph 60 | 86 | 8°¢ | 6 et | Gor] T's BOM + ” ay ” Or | TS 6S | O'eT OT | gg |6'e | e9 9 LG | ot “WOSUBY INL ” ” g 39 09 | Ls Te | L°0r 90 | 8'¢ | #9 TST | PIS | °g “m04ssQ 3 Av Ay Aq & eis | os Fp | 8s | 40 | Fs | 9S 9°c8 | 3°08 | 96 “goa seuy GE jo oSvioaAy 66 |OF ve 188 180 !e9a Usp |Pprerl oop] * ‘LOOU LAXG ATAIA |. poy |-nor | . yep | UST aunt |. d q\ "UOAT |. 2 Ys 3 moves \onenydyatoy' aulgT| ° Dpos |. fo OU) sang |-soyer |222%O boyy 40 99 ar d by Microsoft® igitize HOW CROPS GROW. 156 ‘uosiopuy ‘inweN ¢ “LoplouTosjorg ‘(@) S1oquioay | “(%) aoprouypsjorg ‘ayo Aq ‘uUBMYOH » (3000p ‘Tp y susmils, [eo ler lero lrelserlemirve lewlet ‘aHaIT NOLLOO “LOS “d ‘[onULTT 8,1oJULTY T0WOD sroUINT, “TPIT Y sues 90 beste Up | (aera | 90 | 39 aa | Ut | 0°98 | OF (4) “oop ‘yoojrodumt sisAjvuy “dowung yi] gp loown| ee | reel ee |oor! gorl ae | s2z%] se “daHs NOLLOO “‘eeeT Vong ‘Awopvoy wgdiopeyyd ssmpoooorg ‘rowung “ep y!] ¢0 Jo's | Ut | eer] se fees} oo un |Pree lo “GIG “d 'seBT ‘ooudI0g Jo UoNBpossy “WY ssuIpacoorg “ppue-o|| 2-0 | ee | ae | ere] ler we | | oem] re ‘OFST 008 LEV ALO AUg_ of wodoy “yg oouowmvg | TT | | et oerloo |relrs to bares loo "SHIVLIS NOLLOO ” ” ” ras ” JSOU5ITT|! 6ST | $°6 SOT | TST | 99 | 9°68 | TOT | 6'6E | Le | L'6T ‘soqdteD Jo oarsnjoxo ‘soxdquary gf Uy aSujusord ysoarog|! o's} 0'0 | 079 | 0'@ [oo fen lor lop | rerl oe Fsromo ,, 9h 109 LOT) 9k | OT | 0°08 | LUE | BL | 92s] EOL: ‘Teqdury ,, Sh |00 | eer] t9 |o0 |orelor | apr | coe | #6 “TODUDAL 5 9L | OF g8 |T6 | &e | 8 ee] os | 19 | ses | E'er “m0js8Q Y AvAy Aq Get | OF 96 | SL | OL | Fee | Se | Fel | OT | OST US 1Gt Ser 149 180 18! Ss 109 | Ss! 6 OT INUNGL 9 ” qsousty|| 3°9T | 97s TIL] F'9 | 6b | 8H] eh | 06s | 6:08 | Ets ‘sosA[eUy 9 UL ostius.10d ysomo7q|| LS | O'T 69 | PT 190 | Te) os | 6 OL] As | ost ms +'S10T]}0 4, ” € .o4y OTE] OT 26 (Gr | TL | 4s] r9 | Sat | ese | eer “moyssO AB AA Aq ” g 86 | 9g fh | 0G | 6G | L 6s} 9 | Be] us | eer “sosA[vUY 9 Jo OSvIBAW|| SOL | Le PS ibs 106 1 Leelos | seri oars “S$dOL LOUUVO » Pp ee ysoystA|| BL | 9g 68 [66 | 8s | oes | e6r | ste | oe | sez S3ale s/S8a ESozdle Clo 83/2. lls 2238/2, °jos2 SASVslosdleeslescls SBSIESTIR US SOSSSlStES/SSSIS-EzIS SSS/SF elses BzSSEIS S/ZRS|S S/S S88|8 5/288 Seek he = rej in i .|Period IIL.| Period IV. | Period V. Beginning - Blossomed.| toripen. |. Ripe. 5 564.8] 105.1) 545.0] Loss| 550.6] Loss 8} 82. | 89. . [matters $2.9 14 8) Loss itrogenous 916.7} 292.1/1242.6) 325.9/1340.0) 97.4. chews naaawaeas 202 43.9] 317.8] 115.0) 351.6] 34.2 Organic matter........... 419.2 |1292.2] 873,0/1767.21 475.1/2203.0! 435.8/2331.61 128.6 Silica ........ nine eieaiessvigied 6.39 | 15,82) 9.43) 23.45] 9.63] 34.66) 9.21) 36.32) . 1.66 Sulphuric acid 1.06 2.71) 1.65) 2.63] 0 | 483) 2.121 ° 5. 0.41 Phosphoric aci 3.27 5.99) 2.72) 10.32] 4.33) 12.90} 2.58) 14.23] 1.33 Oxide of iron 0.20 0.46} 0.26] 0.61) 0.15} 0.83)" 0.22] 0.58] Loss LUNG sseande 4.43 8.50} 4.02] 11.60] 3.10} 14.49] 2.89] 14.71] 0.22 Magnesia. . 1.53 Q.7t) 1.18) 8.71}. 1.01] 5.42) 1.71) 6.45] 1. Chlorine 2.28 3.62] 1.34] 5.32) 1.70] 5.95) 0.64) 5.78] Loss 0.86 1.28} 0.42) 1.47] 0.19) 1.12} Loss] 0.87] Loss 17.05 | 31.11] 14,06) 40.20} 9.09) 44.53) 4,13) 43.76] Zoss 36.60 | 70.08} 33,45/100.41] 80-2 ow 8 = iS Co t ~w 5 oo . rx) 8 oO 8 Pe a wo 455.8 1508.6 907.811867.6 504.012523.8! 456.2/2458.5] 134.7 Dry Matter is 1, The plane increases in total weight, (dry matter,) through all its growth, but to unequal degrees in different periods. The greatest growth occurs at the time of head- ing out; the slowest, within ten days of maturity. We may add that the increase of the oat after blossom takes place mostly in the seed, the other organs gaining but little. The lower leaves almost cease to grow after- the 2d period. 2. Fiber is produced most largely at the time of head- ing out, (2d period.) When the plant has finished blos- soming, (end of 3d period,) the formation of fiber entirely ceases. Afterward there appears to occur a slight diminu- ? The weights in this table are grams. One gram = 15.434 grains, As the weights have mostly a comparative value, reduction to the English sean is unnecessary Digitized by Microsoft® COMPOSITION IN SUCCESSIVE STAGES. 215 tion of this substance, probably due to unavoidable loss of lower leaves, but not toa resorption or ai saa in the plant. 3. Fat is formed most largely at the time of blossom. It ceases to be produced some weeks before ripening. 4, The formation of Albuminoids is irregular. The greatest amount is organized during the 4th period, (after blossoming. The gain in albuminoids within this period is two-fifths of the total amount found in the ripe plant, and also is nearly two-fifths of the entire gain of or dance substance in the same period. The absolute amount or- ganized in the 1st period is not much less than in the 4th, but in the 2d, 3d, and 5th periods, the quantities are con- siderably smaller. Bretschneider gives the data for comparing the produc- tion of albuminoids in the oat crop examined by him with Arendt’s results. Taking the quantity found at the con- clusion of the Ist period as 100, the amounts gained during the subsequent periods. are related as follows: PERIODS. - 2% I UL te iit) iv. 1, m& Iv, v. Avendt..........100 67. 46 (113) 120 (238) 36 Bretschneider ...100 ? ? (165) 62 (227) 35 We perceive striking differences in the comparison. In Bretschneider’s crop, the increase of albuminoids goes on most rapidly i in the 8d period, and sinks rapidly during the time when in Arendt’s plants it attained the maximum. | Curiously enough, the gain in the 2d, 3d, and 4th periods, : taken together, is in both cases as good as identical, (233 and 227,) and the gain during the last period is also equal.’ This coincidence is doubtless, however, merely accidental. Comparisons-with other crops of oats,examined,though very incompletely, by Stéckhardt, (Chemischer Ackersmant, 1855,) and Wolff, (Die Erschipfung des Bodens durch die Cultur, 1856,) demonstrate that the rate of assimilation is not related to any special times or periods of development, Digitized by Microsoft® 216 HOW CROPS GROW. but depends upon the stores of food accessible to the plant and the fuvorableness of the weather to growth. The following figures, which exhibit for each period of both crops a comparison of the gain in albuminoids with the increase of the other organic matters, further demon- strate that in the act of organization, the nitrogenous prin- ciples have no close quantitative relations to the non-ni- trogenous bodies, (amyloids and fats.) The quantities of albuminoids gained during each period being represented by 10, the amounts of amyloids, etc., are seen from the subjoined ratios: PERIODS. Ratio in I, II & Ill. IV. Me Ripe Plant. Arendt......... 10: 84 10: 114 10: 28 10. 25 10 : 66 Bretschneider..10: 30 10: 50 10:46 10: 120 10: 51 5. The Ash-ingredients of the oat are absorbed through- out its entire growth, but in regularly diminishing quan- tity. The gain during the Ist period being 10, that in the 2d period is 9,in the 38d, 8, in the 4th, 54, in the 5th, 2 nearly. The ratios of gain in ash-ingredients to that in entire dry substance, are as follows, ash-ingredients being as- sumed as 1, in the successive periods : 12 12hy 1s OY, Ve 16, 1 2 83) Te 19, Accordingly, the absorption of ash-ingredients is not pro- portional to the growth of the plant, but is to some degree accidental, and independent of the wants of vegetation. Recapitulation.— Assuming the quantity of each proxi- mate element in the ripe plant as 100, it contained at the end of the several periods the following amounts: Fiber. Fat. Amyloids. Albuminoids. Ash. I. Period, 18°, 20° |p 15°, 27° | 29 |g i oe 81 ‘* 50 “ 47 45 55“ i 100 ‘ 85 “ 70‘ 57 79 “ Iv. « 100 ‘« 100 92 «° 90 “ 95“ Vi. Oe 100 ‘“ 100 ‘ 100 “ 100 “* - 100 * Digitized by Microsoft® COMPOSITION IN SUCCESSIVE STAGES. 217 The gain during each period was accordingly as fol- lows: Fiber. Fat. Amyloids. Albuminoids. Ash. I, Reread 18° |o: 20° |o 15° [, 27 9 29° |o II. 63“ 380‘ 82 “6 16% i Tit. 8 19 “¢ 35 ee hf in* 24“ Iv. « i 15“ aa 33 * 16 * Vv. “ce 0 (Ts 0 “ 8 “a 10 ce 5 ae 100 ‘ 100 ‘* 100 ‘“ 100 ‘ 100 ‘ 6.—As regards the individual ingredients of the ash, the plant contained at the end of each period the follow- ing amounts,—the total quantity in the ripe plant being taken at 100. Corresponding results from Bretschneider enclosed in () are given for comparison. Sulphuric Phosphoric Acid, cid, Silica. Lime. Magnesia. Potash, Percent. Percent. Percent. Percent. Percent. Percent. EPeriod, 18 (22) 20 (42) 8B 2B) 8 (31) ACBL) 89. 42) ee atc aD Boa BR 63) #5 fC 88) A} C3) Bf ( 89) IV, “ — 93°(7) 9) (89) ML C74) 99° CT) BL CTT) 100 (100) Ve 100 (100) 100 (a0) 400 (400) 100 (100) 100 (100) 100 (95%) The gain (or loss, indicated by the minus sign —) in these ash-ingredients during each period is given below. Sitica, Suparic Phosphoric Time. Magnesia. Potash. Percent. Percent. Per cent. Percent. Percent. Per cent. pi Period, 38 (22) 20 (42) "2B. 23) BW CSL) BA (31) BC 4B) ur «= gots «Fhe a hea Bhcaey BRC ay BRC az) IV) 83°( 45) 88 (—5#) 18 (19) 20 (9) 2H (4) C11) ve “© "F ¢28) 10 (55) 9 CMT) 1 CAT) 18 08) 5) 100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 100 (100) These two independent investigations could hardly give all the discordant results observed on comparing the above figures, as the simple consequence of the unlike mode of conducting them. We observe, for example, that in the last period Arendt’s plants gathered less stéiea than in any other—only 7°|, of the whole. On the other hand, Bret- schneider’s crop gained more silica in this than in any * In these instances Bretschneider’s later cropscontained less sulphuric acid, lime, and patash, than the earlier. This result may be due to the washing of the crop by rains, but is probably caused by unequal development of the several plots. 10 Digitized by Microsoft® 218 HOW CROPS GROW. other single period, viz.: 28°|, A similar statement is true of phosphoric acid. It is obvious that Bretschnei- der’s crop was taking up fixed matters much more vigor- ously in its last stages of growth, than were Arendt’s plants. As to potash we observe that its accumulation ceased in the 4th period in both cases. It is, on the whole, plain that we cannot safely draw from these interesting researches any very definite conclusions as to the rate and progress of assimilation and growth in the oat plant, beyond what have been already pointed out. €.—Translocation of substances in the Plant,—The translocation of certain matters from one part of the plant to another is revealed by the analyses of Arendt, and since such changes are of interest from a physiological point of view, we may recount them here briefly. It has been mentioned already that the growth of the stem, leaves, and ear, of the oat plant in its later stages probably takes place to a great degree at the expense of the roots. It is also probable that a transfer of amyloids, and certain that one of albuminoids, goes on from the leaves through the stem into the ear. Silica appears not to be subject to any change of posi- tion after it has once been fixed by the plant. Chlorine likewise reveals no noticeable mobility. On the other hand phosphoric acid passes rapidly from the leaves and stem towards or into the fruit in the earlier as well as in the later stages of growth, as shown by the following figures: 1,000 ‘plants contained in the various periods, quantities (grams) of phosphoric acid as follows: 1st Period, 2d Period. 3d Period. 4th Period. 5th Period. 3 lower joints of stem 0.47 0.20 0.21 0.20 0.19 2middle ‘ * — 0.39 Lt 0.46 0.18 Upper joint sh _ 0.66 1.73 0.81 0.39 3 lower leaves ee 1.05 0.70 0.69 0.51 0.35 2upperleayes 1.75 1.67 1,18 0.74 0.59 Ear — 2.36 5,36 10.67 12,52 Digitized by Microsoft® COMPOSITION IN SUCCESSIVE STAGES. 219 Observe that these absolute quantities diminish in the stem and leaves after the 1st or 3d period in all cases, and increase very rapidly in the ear. Arendt found that sulphuric acid existed to a much greater degree in the leaves than in the stem, throughout the entire growth of the oat plant, and that after blos- soming the lower stem no longer contained sulphur in the form of sulphuric acid at all, though its total in the plant considerably increased. It is almost certain, then, that sulphuric acid originates, either partially or wholly, by oxidation of sulphur or some sulphurized compound, in the upper organs of the oat. Magnesia is translated from the lower stem into the upper organs, and in the fruit, especially, it constantly in- creases in quantity. There is no evidence that /iéme moves upward in the plant. On the contrary, Arendt’s analyses go to show that in the ear during the last period of growth, it dimin- ishes in quantity, being, perhaps, replaced by magnesia. As to potash, no transfer is fairly indicated except from the ears. These contained at blossoming (period III) a maximum of potash. During their subsequent growth the amount of potash diminished, being probably displac- ed by magnesia. The data furnished by Arendt’s analyses, while they in- dicate a transfer of matters in the cases just named and in most of them with great certainty, do not and cannot from their nature disprove the fact of other similar changes, and cannot fix the real limits of the movements which they point out. Digitized by Microsoft® DIVISION IL. THE STRUCTURE OF 'THE PLANT AND OFFICES OF ITS ORGANS. CHAPTER IL GENERALITIES. We have given a brief description of those elements and compounds which constitute the plant in a chemical sense. They are the materials—the stones and timbers, so to speak—out of which the vegetable edifice is built. It is important in the next place to learn how these building materials are put together, what positions they occupy, what purposes they serve, and on what plan the edifice is constructed. It is impossible for the builder to do his work until he has mastered the plans and specifications of the architect. So it is hardly possible for the farmer with certainty to contribute in any great, especially in any new degree, to the upbuilding of the plant, unless he is acquainted with the mode of its structure and the elements that form it. It is the happy province of science to add, to the vague and general information which the observation and experience of generations has taught, a more definite and particular knowledge,—a knowledge acquired by study purposely and carefully directed to special ends. : An acquaintance with the parts and structure of the plant is indispensable for understanding the mode by which 220 Digitized by Microsoft® ORGANS OF THE PLANT. 221 it derives its food from external sources, while the ingen- ious methods of propagation practiced in fruit and flower culture are only intelligible by the help of this knowledge. ORGANISM OF THE Piant.— We have at the outset spoken of organic matter, of organs and organization. It is in the world of life that these terms have their fittest application. The vegetable and animal consist of numer- ous parts, differing greatly from each other, but each essen- tial to the whole. The root, stem, leaf, flower, and seed, are each instruments or organs whose co-operation is need- ful to the perfection of the plant. The plant (or animal), being thus an assemblage of organs, is called an Organism; it is an Organized or Organic Structure. The atmos- phere, the waters, the rocks and soils of the earth, are mineral matters ; they are inorganic and lifeless. In inorganic nature, chemical affinity rules over the transformations of matter. A plant or animal that is dead, under ordinary circumstances, soon loses its form and characters; it is gradually consumed by the atmospheric oxygen, and virtually burned up to air and ashes. In the organic world a something, which we call the Vital Principle, resists and overcomes or modifies the af- finities of oxygen, and ensures the existence of a con- tinuous and perpetual succession of living forms. The organized structure is characterized and distinguish- ed from mineral matter by two particulars: 1, It builds up and increases its own mass by appropri- ating external matter. It assimilates surrounding sub- stances. It grows by the absorption of food. 2. It reproduces itself It comes from, and forms again a seed or germ. ULTmMaTE anp Complex Orcans.—In our account of the Structure of the Plant we shall first consider the ele- ments of that structure—the Primary Organs or Vegetable Cells—which cannot be divided or wounded without ex- Digitized by Microsoft® 222 HOW CROPS GROW. tinguishing their life, and by whose expansion or multipli- cation all growth takes place. Then will follow an account of the complex parts of the plant—its Compound Organs —which are built up by the juxtaposition of numerous cells. Of these we have one class, viz.: the Roots, Stems, and Leaves, whose office is to sustain and nourish the Indi- vidual Plant. These may be distinguished as the Vege- tative Organs. The other class, comprising the Flower and Fruit, are not essential to the existence of the individ- ual, but their function is to maintain the Race. They are the Reproductive Organs. CHAPTER IL. THE PRIMARY ELEMENTS OF ORGANIC STRUCTURE. g 1. i THE VEGETABLE CELL. One of the most interesting discoveries that the micro- scope has revealed, is, that all organized matter originates in the form of minute vesicles or cells. If we examine by the microscope a seed or an egg, we find nothing but a cell-structure—an assemblage of little globular bags or vesicles, lying closely together, an more or less filled with solid or liquid matters. From these cells, then, comes the frame or structure of the plant, or of the animal. In the process of maturing, the original vesicles are often greatly modified in shape and appearance, to suit various purposes; but still, it is always easy, especially in the plant, to find cells of the same essential characters as those occurring in the seed, Digitized by Microsoft® OE ELEMENTS OF ORGANIC STRUCTURE. 223 Cellular Plants.—In those classes of vegetation which depart structurally to the least degree from the seed, and which belong to what are called the “lower orders,* we find plants which consist entirely of cells throughout all the stages of their life, and indeed many are known which are but a single cell, The phenomenon of red snow, frequently observed in Alpine and Aretie regions, is due to a microscopic one-celled plant which propagates with great rapidity, and gives its color to the surface of the snow. In the chem- ist’s laboratory it is often observed that, in the clearest solutions of salts, like the sulphates of soda and Fig. 27. magnesia, a flocculent mould, some- times red, sometimes green, most often white, is formed, which, under the microscope, is seen to be a vegetation consisting of single cells. Brewer's yeast, fig. 27, is nothing more than a mass of one or few-celled plants. In the mushrooms and sea-weeds, as well as in the moulds that grow on damp walls, or upon bread, cheese, etc., and in the brand or blight which infests many of the farmeyr’s crops, we have examples of plants formed exclusively of cells. All the plants of higher orders we find likewise to con- sist chiefly of globular or angular cells. All the growing parts especially, as the tips of the roots, the leaves, flowers, and fruit, are, for the most part, aggregations q of such minute vesicles. If we examine the pulp of fruits, as that © aS of a ripe apple or tomato, we are able, by ™ means of a low magnifier, to distinguish the cells of which it almost entirely con- sists. Fig. 28 represents a bit of the flesh of a ripe pippin, * Viz.: the Cryptogams, including Moulds, and Mushrooms, (Fungi,) Mosses, Ferns, and Sea-Weeds, (Alge@). Digitized by Microsoft® 224 HOW CROPS GROW. magnified 50 diameters. ‘The cells mostly cohere together, but readily admit of separation. Structure of the Cell.—By the aid of the microscope it is possible to learn something with regard to the inter- nal structure of the cell itself. Fig. 29 exhibits the ap- pearance of a cell from the flesh of the Jerusalem Arti- choke, magnified 230 diameters; externally the membrane, or wall of the cell, is seen in section. This membrane is filled and distended by a transparent liquid, the sap or free water of vegetation. Within the cell is observed a round body, b b, which is called the nwcleus, and upon * this is seen a smaller nucleolus, e. Lining the interior of the cellmembrane and E ea connected with the nucleus, is a yellowish, ae turbid, semi-fluid substance of mucilagi- Fig, 29. nous consistence, @, which is designated the protoplasm, or formative layer. This, when more highly magnified, is found to contain a vast number of excessively minute granules. By the aid of chemistry the microscopist is able to dis- sect these cells, which are hardly perceptible to the unas- sisted eye, and ascertain to a good degree how they are constituted. On moistening them with solution of iodine, and afterward with sulphuric acid, the outer membrane— the cell-watl—shortly becomes of a fine blue color. It is accordingly cellulose, the only vegetable substance yet known which is made blue by iodine after, and only after, the action of sulphuric acid. At the same time we observe that the interior, halfliquid, protoplasm, has coagulated and shrunk together,—has therefore separated from the ~ cell-wall, and including with it the nucleus and the smaller granules, lies in the center of the cell like a collapsed bladder. It has also assumed a deep yellow or brown color. If we moisten one of these cells with nitric acid, the cell-wall is not affected, but the liquid penetrates it, Digitized by Microsoft® ELEMENTS OF ORGANIC STRUCTURE. 225 coagulates the inner membrane, and colors it yellow. In the same way this membrane is tinged violet-blue by chlorhydric acid. These reactions leave no room to doubt that the slimy inner lining of the cell is chiefly an albuminoid. It has been termed by vegetable physiol- ogists the protoplasm or formative layer, from the fact that it is the portion of the cell first formed, and that from which the other parts are developed. The protoplasm is not miscible with or soluble in water. It is contractile, and in the living cell is constantly changing its figure, while the granules commonly suspended in it move and circulate as in a stream of liquid. ; If we examine the cells of any other plant we find al- most invariably the same structure as above described, provided the cells are young, i. e., belong to growing parts. In some cases cells consist only of protoplasm and nucleus, being destitute of cell-walls during a portion or the whole of their existence. In studying many of the maturer parts of plants, viz.: such as have ceased to enlarge, as the full-sized leaf, the perfectly formed wood, etc., we find the cells do not cor- respond to the description just given. Jn external shape, thickness, and appearance of the cell-wall, and especially in the character of the contents, there is indefinite variety. But this is the result of change in the original cells, which, so far as our observations extend, are always, at first, formed closely on the pattern that has been explained. Vegetable Tissue.—It docs not, however, usually hap- pen that the individual cells of the higher orders of plants admit of being obtained separately. They are attached together more or less firmly by their outer surfaces, so as to form a coherent mass of cells—a tisswe, as it is termed. In the accompanying cut, fig. 30, is shown a highly magnified view of a portion of a very thin slice across a young cabbage stalk. It exhibits the outline of the ir- 10* Digitized by Microsoft® 226 HOW CROPS GROW. regular empty cells, the walls of which are, for the most part, externally united and appear as one, @. At the points indicated by 8, cavities between the cells are seen, called intercellular spaces. A slice across the potato-tuber, (see fig. 52, p. 277,) has a similar appearance, except that the cells are filled with starch, and it would be scarcely possible to dissect them apart; but when a pota- to is boiled, the starch- grains swell, and the cells, in. consequence, separate from each other, a practi- eal result of which is to make the potato mealy. A thin slice of vegetable ivory (the seed of Phy- telephas macrocarpa), under the microscope, dry or moistened with water, pre- sents no trace of cell-structure, the cells being united as one; however, upon soaking in sulphuric acid, the mass softens and swells, and the individual cells are at once revealed, their surfaces separating in six-sided outlines. Form of Cells.—In the soft, succulent parts of plants, the cells lie loosely together, often with considerable inter- cellular spaces, and have mostly a rounded outline. In denser tissues, the cells are crowded together in the least possible space, and hence often appear six-sided when seen in cross-section, or twelve-sided if viewed entire. A piece of honey-comb is an excellent illustration of the appear- ance of many forms of vegetable cell-tissue. The pulp of an orange is the most evident example of cell-tissue. The individual cells of the ripe orange may be easily separated from each other, as they are one-fourth of an inch or more in length. Being mature and incapa- ble of further growth, they possess neither protoplasm nor Digitized by Microsoft® ELEMENTS OF ORGANIC STRUCTURE. 227 nucleus, but are filled with a sap or juice containing citric acid and sugar. In the pith of the rush, star-shaped cells are found. In common mould the cells are long and thread-like. Jn the so-called frog-spittle they are cylindrical and attached end to end. In the bark of many trees, in the stems and leaves of grasses, they are square or rectangular. Cotton-fiber, flax and hemp consist of long and slender cells, fig. 831. Wood is mostly made up of elongated cells, tapered at the ends and adhering together by their sides. Fig. 49, ¢. A., p. 271. Each cotton-fiber is a single cell which forms an external appendage to the seed-vessel of the cot- * ton plant. When it has lost its free water of vegetation and become air-dry, its sides collapse and it resembles a twisted strap. A, in fig. 31, exhibits a portion ofa cotton-fiber highly magnified. The flax-fiber, from the inner bark of the flax- stem, 0, fig. 31, is a tube of thicker walls and smaller bore than the cotton-fiber, and hence is more durable than cot- ton. It is very flexible, and even when crushed or bent short, retains much of its original tenacity. Hemp-fiber closely resembles flax-fiber in appearance. Thickening of the Cell-Membrane.—The growth of the cell, which, when young, always has avery delicate outer membrane, often results in the thickening of its walls by the interior deposition of cellu- lose and lignin. This thickening may take place regularly and uniform- ly, or interruptedly. The flax-fiber, b, fig. 31, is an example of nearly uniform thickening. The irregular deposition of cellulose is shown in fig. 32, which exhibits a section from the seeds (cotyledons) of the com- mon nasturtium, (Zrope@olum majus). The original membrane is coated interiorly with several distinct and successively-formed linings, which are not continuous, but are irregularly developed. Seen in section, the Digitized by Microsoft® 228 HOW CROPS Ghkow. thickening has a waved outline, and at points, the original ecll-mem- brane is bare. Were these cells viewed entire, we should see at these points, on the exterior of the cell, dots or circles appearing like orifices, but being simply the unthickened portions of the cell-wall. The cells in fig. 32 exhibit cach a central nucleus surrounded by grains of aleurone, Cell Contents. — Besides the protoplasm and nucleus, the cell usually contains a variety of bodies, which have been, indeed, noticed already as ingredients of the plant, but which may be here recapitulated. Many cells are al- together empty, and consist of nothing but the cell-wall. Such are found in the bark or epidermis of most plants, and often in the pith, and although they remain connected with the actually living parts, they have no proper life in themselves. All living or active cells are distended with liquid. This consists of water, which holds in solution gum, dextrin, inulin, the sugars, organic acids, and other less important vegetable principles, together with various salts, and constitutes the sap of the plant. In oil-plants, droplets of oil oceupy certain cells, fig. 17, p. 90; while in numerous kinds of vegetation, colored and milky juices are found in certain spaces or channels between the cells. The water of the cell comes from the soil, as we shall hereafter see. The matters, which are dissolved in the sap or juices of the plant, together with the semi-solid proto- plasm, undergo transformations resulting in the production of solid substances. By observing the various parts of a plant at the successive stages of its development, under the microscope, we are able to trace within the cells the formation and growth of starch-grains, of crystalloid and granular bodies consisting chiefly of vegetable casein, and of the various matters which give color to leaves and flowers. The circumstances under which a cell developes deter- mine the character of its contents, according to laws that are hidden from our knowledge. The outer cells of the potato-tuber are incrusted with corky matter, the inner Digitized by Microsoft® ELEMENTS OF ORGANIC STRUCTURE. 229 ones, most of them, are occupied entirely with starch, fig. 52, p. 277. In oats, wheat, and other cereals, we find, just within the empty cells of the skin or epidermis of the grain, a few layers of cells that contain scarcely anything but albuminoids, with a little fat; while the interior cells are chiefly filled with starch; fig. 18, p. 106. Transformations in Cell Contents.—The same cell may exhibit a great variety of aspect and contents at different periods of growth. This is especially to be observed in the seed while developing on the mother plant. Hartig has traced these changes in numerous plants under the mi- croscope. Accor ding to this observer, the cell-contents of the seed (cotyledons) of the common nasturtium, (Zrop- eolum majus,) run through the following metamorphoses. Up to a certain stage in its development the interior of the cells are nearly devoid of recognizable solid matters, other than the nucleus and the adhering protoplasm. Shortly, as the growth of the seed advances, green grains of chlorophyll make their appearance upon the nucleus, completely covering it from view. At a later stage, these grains, which have enlarged and multiplied, are seen to have mostly become detached from the nucleus, and lie near to and in contact with the cell-wall. Again, in a short time the grains have lost their green color and have assumed, both as regards appearance and deportment with iodine, all the characters of starch. Subsequently, as the seed hardens and becomes firmer in its tissues, the micro- scope reveals that the starch-grains, which were situated near the cell-wall, have vanished, while the cell-wall itself has thickened inwardly—the starch having been convert- ed into cellulose. Again, later, the nucleus, about which, in the meantime, more starch-grains have been formed, undergoes a change and disappears ; then the starch-grains, some of which have enlarged while others have vanished, are found to be imbedded in a pasty matter, which has the reactions of an albuminoid. From this time on, the Digitized by Microsoft® 230 HOW CROPS GROW. starch-grains are gradually converted from their surfaces inwardly into smaller grains of aleurone, which, finally, when the seed is mature, completely occupy the cells, In the sprouting of the seed similar changes occur, but in reversed order. The nucleus reappears, the aleurone dis- solves, and even the cellulose stratified upon the interior of the cell, fig. 32, wastes away and is converted into soluble food (sugar?) for the seedling. The Dimensions of Vegetable Cells are very various. A creeping marine plant is known—the Cauwlerpa prolifera, x \ Y \ SN : i \ Mh , ‘\\ . Fig. 33. fig. 33,—which consists of a single cell, though it is often a foot in length, and is branched with what have the ap- pearance of leaves and roots. The pulp of the orange con- sists of cells which are one-quarter of an inch or more in diameter. Every fiber of cotton is a single cell. In*most Digitized by Microsoft® ELEMENTS OF ORGANIC STRUCTURE 231 cases, however, the cells of plants are so small as to re- quire a powerful microscope to distinguish them,—are, in fact, no more than 1-1200th to 1-200th of an inch in diam- eter; many are vastly smaller, Growth.—The growth of a plant is nothing more than the aggregate result of the enlargement and multiplication of the cells which compose it. In most cases the cells at- tain their full size ina short time. The continuous growth of plants depends, then, chiefly on the constant and rapid formation of new cells. Cell-multiplication.—The young and active cell always contains a nucleus, (fig. 84, 6.) Such a cell may produce a new cell by dzvision. In this process the nucleus, from which all cell-growth appears to originate, is observed to re- solve itself into two parts, then the protoplasm, @, begins to contract or in- fold across the cell in a line correspond- ing with the division of the nucleus, until the opposite infolded edges meet—like Fig 34, the skin of a sausago where a string is tightly tied around it,—thus separating the two nuclei and inclosing each within its new cell, which is completed by a further external growth of cellulose. In one-celled plants, like yeast, (fig. 35,) the new cells thus formed, bud out from the side of the parent-cell, and before they obtain full size become entirely detached from it, or, as in higher plants, the new cells remain adher- ing to the old, forming a tissue. In free cell-formation nuclei are observed to develope in the protoplasm of a parent cell, which enlarge, surround themselves with their own protoplasm and cell-membrane, and by the resorption or death of the parent cell become independent of the latter. Fig. 85. Digitized by Microsoft® 232 HOW CROPS GROW. The rapidity with which the vegetable cells may multi- ply and grow is illustrated by many familiar facts. The most striking cases of quick growth are met with in the mushroom family. Many will recollect having seen on the morning of a June day, huge puff-balls, some as large as a peck measure, on the surface of a moist meadow, where the day before nothing of the kind was noticed. In such sudden growth it has been estimated that the cells are produced at the rate of three or four hundred millions per hour. Permeability of Cells to Liquids, Although the high- est magnifying power that can be brought to bear upon the membranes of the vegetable cell fails to reveal any apertures in them,—they being, so far as the best-assisted vision is concerned, completely continuous and imperforate, —they are nevertheless readily permeable to liquids. This fact may be elegantly shown by placing a delicate slice from a potato-tuber, immersed in water, under the microscope, and then bringing a drop of solution of iodine in contact with it. Instantly this reagent penetrates the walls of the unbroken cells without perceptibly affecting their appearance, and being absorbed by the starch-grains, at once colors them intensely purplish-blue. The particles of which the cell-walls and their contents are composed, must be separated from each other by distances greater than the diameter of the particles of water or of other liquid matters which thus permeate the cells, § 2. THE VEGETABLE TISSUES. As already stated, the cells of the higher kinds of plants are united together more or less firmly, and thus consti- tute what are known as VEGETABLE Tissurs. Of these, a large number have been distinguished by vegetable anat- Digitized by Microsoft® ELEMENTS OF ORGANIC STRUCTURE. 233 omists, the distinctions being based either ou peculiarities of form or of function. For our purposes it will be neces- sary to define but a few varieties, viz., Cellular Tissue, Woody Tissue, Bast-Tissue, and Vuseular Tissue. Cellular or Cell-Tissue is the simplest of all, being a mere aggregation of globular or polyhedral cells whose walls are in close adhesion, and whose juices commingle more or less in virtue of this connection. Cellular tissue is the groundwork of all vegetable structure, being the only form of tissue in the simpler kinds of plants, and that out of which all the others are developed. The term parenchyma is synonymous with cell-tissue. Wood-Tissue, in its simplest form, consists of cells that are several or many times as long as they are broad, and that taper at each end to a point. These spindle-shaped cells cohere firmly together by their sides, and “break joints” by overlapping each other, in this way forming the tough fibers of wood. Wood-cells are often more or less thickened in their walls by depositions of cellulose, lignin, and coloring matters, according to their age and position, and are sometimes dotted and perforated, as will be explained hereafter, fig. 53, p. 278. Bast-Tissue is made up of long and slender cells, similar to those of wcod-tissue, but commonly more delicate and flexible. The name is derived from the occurrence of this tissue in the bast, or inner bark. Linen, hemp, and all textile materials of vegetable origin, cotton excepted, con- sist of bast-fibers. Bast-cells occupy a place in rind, corres- ponding to that held by wood-cells in the interior of the stem, fig. 49, p. 271. LProsenchyma is a name applied to all tissues composed of elongated cells, like those of wood and bast. Parenchyma and prosenchyma insensibly shade into each other. Vascular Tissue is the term applied to those unbranched Tubes and Ducts which are found in all the higher orders Digitized by Microsoft® 234 HOW CROPS GROW. of plants, interpenetrating the cellular tissue. There are several varieties of ducts, viz., dotted ducts, ringed or an- nular ducts, and spiral ducts, of which illustrations will be given when the minute structure of the stem comes under notice, fig. 49, p. 271. : The formation of vascular tissue takes place by a simple alteration in cellular tissue. A longitudinal series of ad- hering cells represents a tube, save that the bore is ob- structed with numerous transverse partitions. By the removal or perforation of these partitions a tube is devel- oped. This removal or perforation actually takes place in the living plant by a process of absorption. CHAPTER IIL THE VEGETATIVE ORGANS OF PLANTS. SL: THE ROOT. The Roots of plants, with few exceptions, from the first moment of their development grow downward, in obe- dience to the force of gravitation. In general, they require amoist medium. They will form in water or in moist cot- ton, and in many cases originate from branches, or even leaves, when these parts of the plant are buried in the earth or immersed in water. It cannot be assumed that they seek to avoid the light, because they may attain a full development without being kept in darkness, The Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 235 action of light upon them, however, appears to be unfavor- able to their functions. The Growth of Roots occurs mostly by lengthening, and very little or very slowly by increase of thickness. The lengthening is chiefly manifested toward the outer extremities of the roots, as was neatly demonstrated by Wigand, who divided the young root of a sprouted pea into four equal parts by ink-marks. After three days, the first two divisions next the seed had scarcely lengthened at all, while the third was double, and the fourth eight times its previous length. Ohlerts made precisely similar observations on the roots of various kinds of plants. The growth is confined to a space of about *|, of an inch from the tip. (Linnea, 1837, pp. 609-631.) This peculiarity adapts the roots to extend through the soil in all direc- tions, and to occupy its smallest pores, or rifts. It is likewise the reason that a root, which has been cut off in transplanting or otherwise, never afterwards extends in length. Although the older parts of the roots of trees and of the so-called root-crops acquire a considerable diameter, the roots by which a plant feeds are usually thread-like and often exceedingly slender. Spongioles.—The tips of the rootlets have been termed spongioles, or spongelets, from the idea that their texture adapts them especially to collect food for the plant, and that the absorption of matters from the soil goes on exclu- sively through them, In this sense, spongioles do not exist. The real living apex of the root is not, in fact, the outmost extremity, but is situated a little within that point. Root-Cap.—The extreme end of the root usually consists of cells that have become loosened and in part detached from the proper cell-tissue of the root, which, therefore, shortly perish, and serve merely as an elastic cushion or Digitized by Microsoft® 236 HOW CROPS GROW. cap to protect the true termination or living point of the root in its act of penetrating the soil. Fig. 36 represents a magnified section of part of a barley root, showing the loose cells which slough off from the tip. These cells are filled with air in- stead of sap. Amost strik- ing — illustra- tion of the root- cap is furnished by the air-roots of the so- called Screw Pine, (Panda- nus odoratis- simus,) exhibited in natural dimen- sions, in fig. 87. These air-roots issue from the stem above the ground, and, growing downwards, enter the soil, and become roots in the ordinary sense. When fresh, the diameter of the root is quite uniform, but the parts above the root-cap shrink on drying, while the root-cap itself retains nearly its original dimensions, and thus reveals its different structure. Distinction between Root and Stem,.—Not all the subterranean parts of the plant are roots in a proper Fig. 37. sense, although commonly spoken of as such. The tubers of the potato and artichoke, and the fleshy horizontal parts of the sweet-flag and pepper-root, are merely underground stems, of which many varieties exist. - These and all other stems are easily distinguished from Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 237 true roots by the imbricated buds, of which indications may usually be found on their surfaces, ¢. g., the eyes of _ the potato-tuber. The side or secondary roots are indeed marked in their earliest stages by a protuberance on the primary root, but these have nothing in common with the structure of true buds. The onion-bulb is itself a fleshy bud, as will be noticed subsequently. The true roots of the onion are the fibers which issue from the base of the bulb. The roots of many plants exhibit no buds upon their surface, and are incapable of developing them under any conditions. Other plants may produce them when cut off from the parent plant during the growing season. Such are the plum, apple, poplar, and hawthorn. The roots of the former perish if deprived of connection with the stem and leaves. The latter may strike out new stems and leaves for themselves. Plants like the plum are, therefore, capable of propagation by root-euttings, 7. e, by placing pieces of their roots in warm and moist earth. Tap-Roots.—All plants whose seeds readily divide into two parts, and whose stems increase externally by addi- tion of new rings of growth—the so-cailed dicotyledonous plants, or Hxogens, have, at first, a single descending axis, the tap-root, which penetrates vertically into the ground. From this central tap-root, lateral roots branch out more or less regularly, and these lateral roots subdivide again and again. In many cases, especially at first, the lateral roots issue from the tap-root with great order and regu- larity, as much as is seen in the branches of the stem of a fir-tree or of a young grape vine. In older plants, this order is lost, because the soil opposes mechanical hindrances toregular development. In many cases the tap-root grows to a great length, and forms the most striking feature of the radication of the plant. In others it enters the ground but a little way, or is surpassed in extent by its side branches. The tap-root is conspicuous in the Canada thistle, dock, (Rumex,) and in seedling fruit trees. The Digitized by Microsoft® 238 HOW CROPS GROW. upper portion of the tap-root of the beet, turnip, carrot, and radish, expands under cultivation, and becomes a fleshy, nutritive mass, in which lies the value of these plants for agriculture. The lateral roots of other plants, as of the dahlia and sweet potato, swell out at their ex- tremities to tubers. Crown Roots.—Monocotyledonous plants, or Endogens, z.é., plants whose seeds do not split with ease into two nearly equal parts, and whose stems increase by inside growth, such as the cereals, grasses, lilies, palms, etc. have no single tap-root, but produce crown roots, 7. e., a number of roots issue at once in quick succession from the base of the stem. This is strikingly seen in the onion and hyacinth, as well as in maize, Rootlets.—This term we apply to the slender roots, usually not larger than a knitting needle, and but a few inches long, which are formed last in the order of growth, and correspond to the larger roots as twigs correspond to the branches of the stem. Tur Orrices oF THE Root are threefold: 1. To fix the plant in the earth and maintain it, in most cases, in an upright position, 2, To absorb nutriment, from the soil for the growth of the entire plant, and, 3. In case of many plants, especially of those whose terms of life extend through several or many years, to serve as a store-house for the future use of the plant. 1, The Firmness with which a Plant is fixed in the Ground depends upon the nature of its roots. It is easy to lift an onion from the soil, a carrot requires much more force, while a dock may resist the full strength of a pow- erful man, A small beech or seedling apple tree, which has a tap-root, withstands the force of a wind that would prostrate a maize-plant or a poplar,which has only side roots. In the nursery it is the custom to cut off the tap-root of Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 239 apple, peach, and other trees, when very young, in order that they may be readily and safely transplanted as occa- sion shall require. The depth and character of the soil, however, to a certain degree influence the extent of the roots and the tenacity of their hold. The roots of maize, which in a rich and tenacious earth extend but two or three feet, have been traced to a length of ten or even fifteen feet in a light, sandy soil. The roots of clover, and espe- cially those of lucern, extend very deeply into the soil, and the latter acquire in some cases a length of 30 feet. The roots of the ash have been known as many as 95 feet long. (Jour. Roy. Ag. Soc., VI, p. 342.) 2, Root-absorption—The Office of absorbing Plant food from the Soil is one of the utmost importance, and one for which the root is most wisely adapted by the fol- lowing particulars, viz.: a. The Delicacy of its Structure, especially that of the newer portions, the cells of which are very soft and absor- bent, as may be readily shown by immersing a young seedling bean in solution of indigo, when the roots shortly acquire a blue color from imbibing the liquid, while the stem, a portion of which in this plant extends below the seed, is for a considerable time unaltered. It is a common but erroneous idea that absorption from the soil can only take place through the ends of the roots —through the so-called spongioles. On the contfary, the extreme tips of the rootlets cannot take up liquids at all. (Ohlerts, Joc. cit., see p. 249.) All other parts of the roots which are still young and delicate in surface-texture, are constantly active in the work of imbibing nutriment from the soil. - In most perennial plants, indeed, the larger branches of the roots become after a time coated with a corky or oth- erwise nearly impervious cuticle, and the function of ab- sorption is then transferred to the rootlets. This isdemon- Digitized by Microsoft® 240 HOW CROPS GROW. strated by placing the old, brown-colored roots of a plant in water, but keeping the delicate and unindurated ex- tremities above the liquid. Thus situated, the plant with- ers nearly as soon as if its root-surface were all exposed to the air. b. Its Rapid Extension in Length, and the vast Sur- face which it puts in contact with the soil, further adapts the root to the work of collecting food. The length of roots in a direct line from the point of their origin is not, in- deed, a criterion by which to judge of the efficiency where- with the plant to which they belong is nourished; for two plants may be equally flourishing—hbe equally fed by their roots—when these organs, in one case, reach but one foot, and in the other extend two feet from the stem to which they are attached. In one case, the roots would be fewer and longer; in the other, shorter and more numer- ous. Their aggregate length, or, more correctly, the ag- gregate absorbing surface, would be nearly the same in both. The Medium in which Roots Grow has a great influence on their extension. When they are situated in concen- trated solutions, or in a very fertile soil, they are short, and numerously branched. Where their food is sparse, they are attenuated, and bear a comparatively small num- ber of rootlets. Illustrations of the former condition are often seen. Bones and masses of manure are not infre- quently found, completely covered and penetrated by a fleece of stout roots. On the other hand, the roots which grow in poor, sandy soils, are very long and slender. Nobbe has described some experiments which com- pletely establish the point under notice. (Vs. S¢., IV, p. 212.) He allowed maize to grow in a poor clay soil, con- tained in glass cylinders, each vessel having in it a quan- tity of a fertilizing mixture disposed in some peculiar man- ner for the purpose of observing its influence on the roots. When the plants had been nearly four months in growth, Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 241 the vessels were placed in water until the earth was soft- ened, so that by gentle agitation it could be completely removed from the roots. The latter, on being suspended in a glass vessel of water, assumed nearly the position they had occupied in the soil, and it was observed that where the fertilizer had been thoroughly mixed with the soil, the roots uniformly occupied its entire mass. Where the fertilizer had been placed in a horizontal layer at the depth of about one inch, the roots at that depth formed a mat of the finest fibers. Where the fer- tilizer was situated in a horizontal layer at half the depth of the vessel, just there the root-system was spheroidally expanded. In the cylinders where the fertilizer formed a vertical layer on the interior walls, the external roots were developed in numberless ramifications, while the interior roots were comparatively unbranched. In pots, where the fertilizer was disposed as a central vertical core, the inner roots were far more greatly developed than the outer ones. Finally, in a vessel where the fertilizer was placed in a horizontal layer at the bottom, the roots extended through the soil, as attenuated and slightly branched fibers, until they came in contact with the lower stratum, where they greatly increased and ramified. In all cases, the principal development of the roots occurred in the immediate vicinity of the material which could furnish them with nutriment. " It has often been observed that a plant whose aerial branches are symmetrically disposed about its stem, has the larger share of its roots on one side, and again we find roots which are thick with rootlets on one side, and nearly devoid of them on the other. Apparent Search for Food.—It would almost appear, on superficial consideration, that roots are endowed with a kind of intelligent instinct, for they seem to go in search of nutriment. 11 Digitized by Microsoft® 242 HOW CROPS GROW. The roots of a plant make their first issue independently of the nutritive matters that may exist in their neighbor- hood. They are organized and put forth from the plant itself, no matter how fertile or sterile the medium that surrounds them. When they attain a certain develop- ment, they are ready to exercise their office of collecting food. If food be at hand, they absorb it, and, together with the entire plant, are nourished by it—they grow in consequence. The more abundant the food, the better they are nourished, and the more they multiply. The plant sends out rootlets in all directions; those which come in contact with food, live, enlarge, and ramify; those which find no nourishment, remain undeveloped or perish. The Quantity of Roots actually attached to any plant is usually far greater than can be estimated by roughly lifting them from the soil. To extricate the roots of wheat or clover, for example, from the earth, completely, is a matter of no little difficulty. Schubart has made the most satisfactory observations we possess on the roots of several important crops, growing in the field. He sepa- rated them from the soil by the following expedient: An excavation was made in the field to the depth of 6 feet, and a stream of water was directed against the vertical wall of soil until it was washed away, so that the roots of the plants growing in it were laid bare. The roots thus ex- posed in a field of rye, in one of beans, and in a bed of gar- den peas, presented the appearance of a mat or felt of white fibers, to a depth of about 4 feet from the surface of the ground. The roots of winter wheat he observed as deep as 7 feet, in a light subsoil, forty-seven days after sowing. The depth of the roots of winter wheat, winter rye, and winter colza, as well as of clover, was 3-4 fect. The roots of clover, one year old, were 3} feet long, those of two- year-old clover but 4 inches longer. The quantity of roots in per cent of the entire plant in the dry state was found to be as follows. (Chem. Ackersmann, I, p. 193.) Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 243 Winter wheat—examined last of April......... 40,|° ee He ce OO Mayes sate sxe 20.6 «rye i fh SE Bias ae ta 3B“ Peas examined four weeks after sowing........ 44% as es at the time of blossom..... hae Ok Hellriegel has likewise studied the radication of barley and oats, (off, Jahresbericht, 1864, p. 106.) THe raised plants in large glass pots, and separated their roots from the soil by careful washing with water. He observed that directly from the base of the stem 20 to 30 roots branch off sideways and downward. These roots, at their point of issue, have a diameter of*|,, of an inch, but a little lower the diameter diminishes to about *|,,, of an inch: Retaining this diameter, they pass downward, dividing and branching to a certain depth. From these main roots branch out innumerable side roots, which branch again, and so on, filling every crevice and pore of the soil. To ascertain the total length of root, Hellriegel weighed and ascertained the length of selected average portions. Weighing then the entire root-system, he calculated the entire length. He estimated the length of the roots of a vigorous barley plant at 128 feet, that of an oat plant at 150 feet.* He found that a small bulk of good fine soil sufficed for this development ; *|,, cub. foot, (4% 4*2°|, in.,) answered for a barley plant; *|,, cub. foot for an oat plant, in these experiments. Hellriegel observed also that the quality of the soil in- fluenced the development. In rich, porous, garden-soil, a barley plant produced 128 feet of roots, but in a coarse- grained, compacter soil, a similar plant had but 80 feet of roots. Root-Hairs.—The real absorbent surface of roots is, in most cases, not to be appreciated without microscopic aid. The roots of the onion and of many other bulbs, i. e., the fibers which issue from the base of the bulbs, are perfectly © Rhenish feet. Digitized by Microsoft® 244 HOW CROPS GROW. smooth and unbranched throughout their entire length. Fig. 88. Other agricultural plants have roots which are not only visibly branched, but whose finest fibers are more or less thickly covered with minute hairs, scarcely perceptible to the un- assisted eye. These root-hairs consist always of tubular elongations of the external root-cells, and through them the actual root-surface exposed to the soil becomes something almost incal- culable. The accompanying figures illustrate the appearance of root-hairs. Fig. 38 represents a young, seed- ling, mustard-plant. A is the plant, as carefully lifted from, the sand in which it grew, and B the same plant, freed from adhering soil by agitating in water. The entire root, save the tip, is thickly beset with hairs. In fig. 89 a minute portion of a barley- root is shown highly magnified. The hairs are seen to be slender tubes that proceed from, and form part of, the outer cells of the root. The older roots lose their hairs, and suffer a thickening of the outermost layer of cells by the deposition of cork. These dense-walled and nearly imper- vious cells cohere together and constitute a rind, which is not ( found in the young and active roots. As to the development of ( 4 the root-hairs, they are more Fig. 89, Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 245 abundant in poor than in good soils, and appear to be most numerously produced from roots which have other- wise a dense and unabsorbent surface. The roots of those plants which are destitute of hairs are commonly of con- siderable thickness and remain white and of delicate tex- ture, preserving their absorbent power throughout the whole time that the plant feeds from the soil, as is the case with the onion. The Silver Fir, (Ades pectinata,) has no root-hairs, but its rootlets are covered with a very delicate cuticle highly favorable to absorption. The want of root-hairs is further compensated by the great number of rootlets which are formed, and which, perishing mostly before they become superficially indurated, are continually replaced by new ones during the growing season. (Schacht, Der Baum, p. 165.) Contact of Roots with the Soil.—The root-hairs, as they extend into the soil, are naturally brought into close contact with its particles. This contact is much more in- timate than has been usually supposed. If we carefully lift a young wheat-plant from dry earth, we notice that each rootlet is coated with an envelope of soil. This ad- heres with considerable tenacity, so that gentle shaking fails to displace it, and if it be mostly removed by vigor- ous agitation or washing, the root-hairs are either found to be broken, or in many places inseparably attached to the particles of earth. Fig. 40 exhibits the appearance of a young wheat- plant as lifted from the soil and pretty strongly shaken. S, the seed; 6, the blade; e, roots covered with hairs and enveloped in soil, Only the growing tips of the roots, w, which have not put forth hairs, come out clean of soil. Fig. 41 represents the roots of a wheat-plant one month older than those of the previous figure. In this instance not only the root-tips are naked as before, but the older / Digitized by Microsoft® 246 : HOW CROPS GROW. Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 247 parts of the primary roots, e, and of the secondary roots, n, no longer retain the particles of soil; the hairs upon them being, in fact, dead and decomposed. The newer parts of the root alone are clothed with active hairs, and to these the soil is firmly attached as before. The next il- lustration, fig. 42, exhibits the appearance of root-hairs with adhering particles of earth, when magnified 800 di- ameters—A, root-hairs of wheat-seedling like fig. 40; B, of oat-plant, both from loamy soil. Here is plainly seen the intimate attachment of the soil and root-hairs. The Digitized by Microsoft® 248 HOW CROPS GROW. latter, in forcing their way against considerable pressure, often expand around, and partially envelope, the particles of earth. Imbibition of Water by the Root.—The degree of force with which active roots imbibe the water of the soil is very great, is, in fact, sufficient to force the liquid upward i into the stem and to exert a con- tinual pressure on all parts of the plant. When the stem of a plant in vigorous growth is cut off near the root, and a pressure-gauge is attached to it as in fig. 43, we have the means of observing and measuring the force with which the roots absorb water. The pres- sure-gauge contains a quantity of mercury in the middle reservoir, 6, and the tube, ¢. It is attached to the stem of the plant, p, by a stout india-rubber pipe, g.* For accurate measurements the space, a and 6, should be filled with wa- ter. Thus arranged, it is found that water will enter @ through the stem, and the mercury will rise in the tube, e, until its pres- Fig. 43. sure becomes sufficient to balance the absorptive power of the roots. IJlales, who first ex- perimented in this manner 140 years ago, found in one instance, that the pressure exerted on a gauge attached in spring-time to the stump of a grape vine, supported a column of mercury 324 inches high, which is equal to a column of water of 364 ft. Hofmeister obtained on other plants, rooted in pots, the following results: * For experimenting on small plants, a simple tube of glass may be adjusted to the stump vertically by help of a rubber connector, Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 249 Bean (Phaseolus multiflorus) 6 inches of mercury. Nettle - - - - 4 « Vine - - - - 29 s Seat of Absorptive Force.—Dutrochet demonstrated that this power resides in the surface of the young and active roots. At least, be found that absorption was ex- erted with as much force when the gauge was applied to near the lower extremity of a root, as when attached in the vicinity of the stem. In fact, when other conditions are alike, the column of liquid sustained by the roots of a plant is greater, the less the length of stem that remains attached to them. The stem thus resists the rise of liquid in the plant. While the seat of absorptive power in the root lies near the extremities, it appears from the experiments of Ohlerts that the extremities themselves are incapable of imbibing water. In trials with young pea, flax, lupine, and horse- radish plants with unbranched roots, he found that they withered speedily when the tips of the roots were immers- ed for about one-fourth of an inch in water, the remaining parts being in moist air. Ohlerts likewise proved that these plants flourish when only the middle part of their roots is immersed in water. Keeping the root-tips, the so-called spongioles, in the air, or cutting them away alto- gether, was without apparent effect on the freshness and vigor of the plants. The absorbing surface would thus appear to be confined to those portions of the root upon which the development of root-hairs is noticed. The absorbent force is manifested by the active rootlets, and most vigorously when these are in the state of most rapid development. Jor this reason we find, in case of the vine, for example, that during the autumn, when the plant is entering upon a period of repose from growth, the ab- sorbent power is trifling. The effect of this forcible en- trance of water into the plant is oftentimes to cause the if Digitized by Microsoft® 250 HOW CROPS GROW. exudation of it in drops upon the foliage. This may be noticed upon newly sprouted maize, or other cereal plants, where the water escapes from the leaves at their extreme tips, especially when the germination has proceeded under the most favorable conditions for rapid development, The bleeding of the vine, when severed in the spring- time, the abundant flow of sap from the sugar-maple, and the water-elm, are striking illustrations of this imbibition of water from the soil by the roots. These examples are, indeed, exceptional in degree, but not in kind. Hofimeister has shown that the bleeding of a severed stump is a gen- eral fact, and occurs with all plants when the roots are active, when the soil can supply them abundantly with water, and when the tissues above the absorbent parts are full of this liquid. When it is otherwise, water may be absorbed from the gauge into the stem and large roots, un- til the conditions of activity are renewed. Of the external circumstances that influence the absorp- tive power of the root, may be noticed that of tempera- ture. By observing a gauge attached to the stump of a plant during a clear summer day, it will be usually no- ticed that the mercury begins to rise in the morning as the sun warms the soil, and continues to ascend for a num- ber of hours, but falls again as the sun declines, Sachs found in some of his experiments that at a temperature of 41° F., absorption, in case of tobacco and squash plants, was nearly or entirely suppressed, but was at once renewed. by plunging the pot into warm water. The external supplies of water,—in case a plant is sta- tioned in the soil, the degree of moisture contained in.this medium,—obviously must influence, not perhaps the im- bibing force, but its manifestation. The Rate of Absorption is subject to changes depend- ent on other causes not well understood. Sachs observed that the amount of liquid which issued from potato stalks Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 251 cut off just above the ground, underwent great and con- tinual variation from hour to hour (during rainy weather) when the soil was saturated with water and when the thermometer indicated a constant temperature. Hofmeister states that the formation of new roots and buds on the stump is accompanied by a sinking of the water in the pressure-gauge. Absorption of Nutriment from the Soil.—The food of the plant, so far as it is derived from the soil, enters it in a state of solution, and is absorbed with the water which is taken up by the force acting in the rootlets. The absorp- tion of the matters dissolved in water is in some degree independent of the absorption of the water itself, the plant having, to a certain extent, a selective power. 3. The Root as a Magazine.—In fleshy roots, like those of the carrot, beet, and turnip, the absorption of nutriment from the soil takes place principally, if not en- tirely, by means of the slender rootlets which proceed abundantly from all parts of the main or tap-root, and es- pecially from its lower extremity ; while the fleshy portion serves as a magazine in which large quantities of pectose, sugar, etc., are stored up during the first year’s growth of these, (in our latitude,) biennial plants, to supply the wants of the flowers and seed which are developed the second year. When one of these roots is put in the ground for a second year and produces seed, it is found to be quite exhausted of the nutritive matters which it pre- viously contained in so large quantity. - In cultivation, the farmer not only greatly increases the size of these roots and the stores of organic nutritive ma- terials they contain, but by removing them from the ground in autumn, he employs to feed himself and his cat- tle the substances that nature primarily designed to nour- ish the growth of flowers and seeds during another sum- mer. Digitized by Microsoft® 252 HOW CROPS GROW. Soil-Roots; Water-Roots: Air-Roots,—We may dis- tinguish, according to the medium in which they are formed ~ and grow, three kinds of roots, viz.: soil-roots, water-roots, and air-roots. Most agricultural plants, and indeed by far the greater number of all plants found in temperate climates, have roots adapted exclusively to the soil, and which perish by drying, if long exposed to air, or rot, if immersed for a time in water. Many aquatic plants, on the other hand, die if their _ roots be removed from water, or from earth saturated with water. Air-roots are not common except among tropical plants. Indian corn, however, often throws out roots from the lower joints of the stem, which extend through the air several inches before they reach the soil, The Banyan of India sends out roots from its branches, which penetrate the earth in like manner. Many tropical plants, especially of the tribe of Orchids, emit roots which hang free in the air, and never come in contact with water or soil. A plant, known to botanists as the Zamia spiralis, not only throws out air-roots, ¢ ¢, Fig. 44, from the crown of the main soil-root, but the side rootlets, 0, after extending some distance horizontally in the soil, send from the same point, roots downward and upward, the latter of which, d, pass into and remain permanently in the air. A is the stem of the plant. (Schacht, Anatomie der Gewcichse, Bd. II, p. 151.) Some plants have roots which are equally able to exist and perform their functions, whether in the soil or sub- merged in water. Many forms of vegetation found in our swamps and marshes are of this kind. Of agricul- tural plants, rice is an example in point. Rice will grow in a soil of ordinary character, in respect of moisture, as the upland cotton-soils, or even the pine-barrens of the Carolinas. It flourishes admirably in the tide swamps of Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 253 the coast, where the land is laid under water for weeks at a time during its growth, and it succeeds equally well in fields which are flowed from the time of planting to that of harvesting. (Russell. Morth America, its Agriculture and Climate, p. 176.) The willow and alder, trees which grow on the margins of streams, send a part of their roots into soil that is constantly saturated with water, or into Fig, 44, the water itself; while others occupy the merely moist or even dry earth. Plants that customarily confine their growth to the soil, occasionally throw out roots as if in search of water, and sometimes choke up drain-pipes or even wells, by the pro- fusion of water-roots which they emit. At Welbeck, England, a drain was completely stopped by roots of horseradish plants at a depth of 7 feet. At Thornsby Park, a drain 16 feet deep was stopped en- Digitized by Microsoft® 254 HOW CROPS GROW. tirely by the roots of gorse, growing at a distance of 6 feet from the drain. (Jour. Roy. Ag. Soc., 1, 364.) In New Haven, Conn., certain wells are so obstructed by the aquatic roots of the elm trees, as to require cleaning out every two or three years. This aquatic tendency has been repeatedly observed in the poplar, cypress, laurel, turnip, mangel-wurzel, and grasses, Henrici surmised that the roots which most cultivated plants send down deep into the soil, even when the latter is by no means porous or inviting, are designed especially to bring up water from the subsoil for the use of the plant. The following experiment was devised for the purpose of testing the truth of this view. On the 13th of May, 1862, a young raspberry plant, having but two leaves, was transplanted into a large glass funnel filled with gar- den soil, the throat of the funnel being closed with a paper filter. The funnel was supported in the mouth of a large glass jar, and its neck reached nearly to the bottom of the latter, where it just dipped into a quantity of water. The soil in the funnel was at first kept moderately moist by occasional waterings. The plant remained fresh and slowly grew, putting forth new leaves. After the lapse of several weeks, four strong roots penetrated the filter and extended down the empty funnel-neck, through which they emerged, on the 21st of June, and thenceforward spread rapidly in the water of the jar. From this time on, the soil was not watered any more, but care was taken to maintain the supply in the jar. The plant continued to develope slowly; its leaves, however, did not acquire a vivid green color, but remained pale and yellowish; they did not wither until the usual time late in autumn. The roots continued to grow, and filled the water more and more. Near the end of December the plant had 7-8 leaves, and a height of 8 inches. The water-roots were vigorous, very long, and beset with numerous fibrils and Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 255 buds. In the funnel tube the roots made a perfect tissue of fibers. In the dry earth of the funnel they were less extensively developed, yet exhibited some juicy buds. The stem and the young axillary leaf-buds were also full of sap. The water-roots being cut away, the plant was put into garden soil and placed in a conservatory, where it grew vigorously, and in May bore two offshoots. The experiment would indicate that plants may extend a portion of their roots into the subsoil chiefly for the pur- pose of gathering supplies of water. (Henneberg’s Jour. Sir Landwirthschaft, 1863, p. 280.) This growth towards water must be accounted for on the principles asserted in the paragraph—Apparent Search for Food, (p. 241). The seeds of many ordinary land plants—of plants, in- deed, that customarily grow in a dry soil, such as the bean, squash, maize, etc..—will readily germinate in moist cot- ton or saw-dust, and if, when fairly sprouted, the young plants have their roots suspended in water, taking care that the seed and stem are kept above the liquid, they will continue to grow, and if duly supplied with nutriment will run through all the customary stages of development, producing abundant foliage, flowering, and perfecting seeds, without a moment’s contact of their roots with any soil, (See Water- Culture, p. 167.) If plants thus growing with their roots in a liquid me- dium, after they have formed several large leaves, be care- fully transplanted to the soil, they wilt and perish, unless frequently watered ; whereas similar plants started in the soil, may be transplanted without suffering in the slight- est degree, though the soil be of the usual dryness, and receive no water. The water-bred . seedlings, if abundantly watered as often as the foliage wilts, recover themselves after a time, and thenceforward continue to grow without the need of watering. It might appear that the first-formed water-roots are in- Digitized by Microsoft® 256 HOW CROPS GROW. capable of feeding the plant from a dry soil, and hence the soil must be at first profusely watered; after a time, however, new roots are thrown out, which are adapted to the altered situation of the plant, and then the growth proceeds in the usual manner. The reverse experiment would seem to confirm this view. If a seedling that has grown for a short time only in the soil, so that its roots are but twice or thrice branch- ed, have these immersed in water, the roots already form- ed mostly or entirely perish in a short time. They indeed absorb water, and the plant is sustained by them, but im- mediately new roots grow from the crown with great ra- pidity, and take the place of the original roots, which become disorganized and useless. It is, however, only the young and active rootlets, and those covered with hairs, which thus refuse to live in water. The older parts of the roots, which are destitute of fibrils and which have nearly ceased to be active in the work of absorption, are not af- fected by the change of circumstance. These facts, which are due to the researches of Dr. Sachs, ( Vs. Sé., 2, p. 18,) would naturally lead to the conclusion that the absorbent surface of the root undergoes some structural change, or produces new roots with modified characters, in order to adapt itself to the medium in which it is placed. It would appear that when this adaptation proceeds rapidly, the plant is not permanently retarded iu its growth by a gradual change in the character of the medium which surrounds its roots, as may happen in case of rice and marsh-plants, when the saturated soil in which they may be situated at one time, is slowly dried. Sudden changes of medium about the roots of plants slow to adapt them- selves, would be fatal to their existence. Nobbe has, however, carefully compared the roots of buckwheat, as developed in the soil, with those emitted in water, without being able to observe any structural differ- ences. The facts detailed above admit of partial, if not Digitized by Microsoft® . THE VEGETATIVE ORGANS OF PLANTS. 257 complete explanation, without recourse to the supposition that soil and water-roots are essentially diverse in nature. When a plant which is rooted in the soil is taken up so that the fibrils are not broken or injured, and set into wa- ter, it does not suffer any hindrance in growth, as Sachs has found by late experiments. (Hxperimental Physi- ologie, p. 177.) Ordinarily, the suspension of growth and decay of fibrils and rootlets is due, doubtless, to the mechanical injury they suffer in removing from the soil. Again, when a plant that has been reared in water is planted in earth, similar injury occurs in packing the soil about the roots, and moreover the fibrils cannot be brought into that close contact with the soil which is necessary for them to supply the foliage with water; hence the plant wilts, and. may easily perish unless profusely watered or shielded from evaporation. , The issue of water or soil-roots, either or both, from the same plant, according to the circumstances in which it is placed, finds something analogous in reference to air- roots. As before stated, these chiefly occur on tropical plants, or in shaded, warm, and very moist situations. Schacht informs us that in the dark and humid forest ra- vines of Madeira and Teneriffe, the Laurus Canariensis, a large tree, sends out from its stem during the autumn rains, a, profusion of fleshy air-roots, which cover the trunk with their interlacing branches and grow to an inch in thick- ness. The following summer, they dry away and fall to the ground, to be replaced by new ones in the ensuing au- tumn. (Der Baum, p. 172.) The formation of air-roots may be very easily observed by filling a tall vial with water to the depth of half an inch, inserting therein a a of a common house-plant, the Tradescantia zebrina, so that the cut end of the stem shall stand in the water, and finally corking the vial air-tight. The plant, which is very tenacious of life, and usually grows well in spite of all neglect, is not checked in its vegetative development by the treatment just described, but immediately begins to adapt itself to its new circumstances. Ina few days, if the temperature be 70° or there- about, air-roots will be seen to issue from the joints of the stem. These Digitized by Microsoft® \ 258- HOW CROPS GROW. are fringed with a profusion of delicate hairs, and rapidly extend toa length of from one to two inches. The lower ones, if they chance to penetrate the water, become discolored and decay; the others, however, remain for a long time fresh, and of a white color. As already mentioned, Indian corn frequently produces air-roots. The same is true of the oat, of buckwheat, of the grape-vine, and of other plants of temperate re- gions when they are placed for some time in tropical con- ditions, i. e., when they grow in a rich soil and their over- ground organs are surrounded by a very warm and very moist atmosphere. It has been conjectured that these air-roots serve to ab- sorb moisture from the air and thus aid to maintain the growth of the plant. This subject has been studied by Unger, Chatin, and Duchartre. The observers first named were led to conclude that these organs do absorb water from the air. Duchartre, however, denies their absorptive power. It is probably true that they can and do absorb to some extent the water that exists as vapor in the at- mosphere. At the same time they may not usually con- dense enough to make good the loss that takes place in other parts of the plant by evaporation. Hence the re- sults of Duchartre, which were obtained on the entire plant and not on the air-roots alone. (Zléments de Botanique, p. 216.) It certainly appears improbable that organs which only develope themselves in a humid atmos- phere, where the plant can have no lack of water, should be specially charged with the office of collecting moisture from the air. Root-Excretions,—It has been supposed that the roots of plants perform a function of excretion, the reverse of absorption—that plants, like animals, reject matters which are no longer of use in their organism, and that the re- jected matters are poisonous to the kind of vegetation from which they originated. De Candolle, an eminent French botanist, who first advanced this doctrine, founded Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 259 it upon the observation that certain plants exude drops of liquid from their roots when these are placed in dry sand, and that odors exhale from the roots of other plants. Numerous experiments have been instituted at various times for the purpose of testing this question. The most extensive inquiries we are aware of, are those of Dr, Al- fred Gyde, (Zrans. Highland and Agr. Soc., 1845-7, p. 273-92). This experimenter planted a variety of agricul- tural plants, viz., wheat, barley, oats, rye, beans, peas, vetches, cabbage, mustard, and turnips, in pots filled either with garden soil, sand, moss, or charcoal, and after they had attained considerable growth, removed the earth, ete., from their roots by washing with water, using care not to in- jure or wound them, and then immersed the roots in ves- sels of pure water. The plants were allowed to remain in these circumstances, their roots being kept in darkness, but their foliage exposed to light, from three to seventeen days. In most cases they continued apparently in a good state of health. At the expiration of the time of experi- ment, the water which had been in contact with the roots was evaporated, and was found to leave a very minute amount of yellowish or brown matter, a portion of which was of organic and the remainder of mineral origin. Dr. Gyde concluded from his numerous trials, that plants do throw off organic and inorganic excretions similar in com- position to their sap; but that the quantity is exceedingly small, and is not injurious to the plants which furnish them. In the light of newer investigations touching the struc- ture of roots and their adaptation to the medium which happens to invest them, we may well doubt whether agri- cultural plants in the healthy state excrete any solid or liquid matters whatever from their roots. The familiar excretion of gum, resin, and sugar,* from the stems of * From the wounded bark of the Sugar Pine, (Pinws Lambertiana,) of Cali- fornia, Digitized by Microsoft® 260 HOW CROPS GROW. trees appears to result from wounds or disease, and the matters which in the experiments of Gyde and others were observed to be communicated by the roots of plants to pure water, probably came either from the continual pushing off of the tips of the rootlets by the interior growing point—a process always naturally accompanying the growth of roots—or from the eens of the absorbent root-hairs. - Under certain circumstances, small quantities of mineral salts may indeed diffuse out of the root-cells into the water of the soil. This is, however, no physiological action, but a purely physical process. Vitality of Roots.—It appears that in case of most plants the roots cannot long continue their vitality if their connection with the leaves be interrupted, unless, indeed, they be kept at a winter temperature. Hence weeds may be effectually destroyed by cutting down their tops; al- though, in many cases, the process must be several times repeated before the result is attained. The roots of our root-crops, properly so-called, viz, beets, turnips, carrots, and parsnips, when harvested in au- tumn, contain the elements of a second year’s growth of stem, etc., in the form of a bud at the crown of the root. If the crown be cut away from the root, the latter cannot vegetate, while the growth of the crown itself is not thereby prevented. As regards internal structure, the root closely resembles the stem, and what is stated of the latter on subsequent pages, applies in all essential points to the former. § 2. THE STEM. Shortly after the protrusion of the rootlet from a ger- minating seed, the Stem makes its appearance. It has, in general, an upward direction, which in many plants is per- Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 261 manent, while in others it shortly falls to the ground and grows thereafter horizontally. All plants of the higher orders have stems, though in many instances they do not appear above ground, but ex- tend beneath the surface of the soil, and are usually con- sidered to be roots. While the root, save in exceptional cases, does not de- velop other organs, it is the special function of the stem to bear the leaves, flowers, and seed, of the plant, and even in certain tribes of vegetation, like the cacti, which have no leaves, it performs the offices of these organs. In gen- eral, the functions of the stem are subordinate to those of the organs which it bears—the leaves and flowers. It is the support of these organs, and only extends in length or thickness with the apparent purpose of sustaining them either mechanically or nutritively. Buds.—In the seed the stem exists in a rudimentary state, associated with undeveloped leaves, forming a bud. The stem always proceeds at first from a bud, during all its growth is terminated by a bud at every growing point, and only ceases to be thus tipped when it fully accom- plishes its growth by the production of seed, or dies from injury or disease. In the leaf-bud we find a number of embryo leaves and leaf-like scales, in close contact and within each other, but all attached at the base, to a cen- tral conical axis, fig. 45. The open- ing of the bud con- sists in the lengthening of this axis, which is the stem, and the consequent separation of the leaves from each Digitized by Microsoft® Fig. 45. 262 HOW CROPS GROW. other. If the rudimentary leaves of a bud be represented by a nest of flower-pots, the smaller placed within the larger, the stem may be signified by a rope of India- rubber passed through the holes in the bottom of the pots. The growth of the stem may now be shown by stretch- ing the rope,whereby the pots are brought away from each other, and the whole combination is made to assume the char- acter of a fully developed stem, bearing its leaves at regular intervals; with these important differences, that the por- tions of stem nearest the root extend more rapidly than those above them, and the stem has within it the material and the mechanism for the continual formation of new buds, which unfold in successive order, In fig. 45, which represents the two terminal buds of a lilac twig, is shown not only the external appearance of the buds, which are covered with leaf-like scales, imbricated like shingles on a roof; but, in the section, are seen the edges of the undeveloped leaves attached to the conical axis. All the leaves and the whole stem of a twig of one summer’s growth thus exist in the bud, in plan and in miniature. Subsequent growth is but the development of the plan. In the flower-bud the same structure is manifest, save that the rudimentary flowers and fruit are enclosed within the leaves, and may often be seen plainly on cutting the bud open. Culms; Nodes; Internodes.—The grasses and the com- mon cereal grains have single, unbranched stems, termed culms in botanical language. The leaves of these plants clasp the stem entirely at their base, and at this point is formed a well-defined, thickened knot or node in the stem. The portions of the stem between these nodes are termed internodes. Branching Stems,—Other agricultural plants besides those just mentioned, and all the trees of temperate cli- Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 263 mates, have branching stems, originating in the following manner: As the principal or main stem elongates, so that the leaves arranged upon it separate from each other, we may find one or more side or axillary buds at the point where the base of the leaf or of the leaf-stalk unites with the stem. From these buds, in case their growth is not checked, side-stems or branches issue, which again sub- divide in the same manner into branchlets. In perennial plants, when young, or ,in their young shoots, it is easy to trace the nodes and internodes, or the points where the leaves are attached and the intervening spaces, even for some time after the leaves, which only endure for one year, are fallen away. The nodes are mani- fest by the enlargement of the stem, or by the sear covered with corky matter, which marks the spot where the leaf- stalk was attached. As the stem grows older these indi-— cations of its early development are gradually obliterated. In a forest where the trees are thickly crowded, the lower branches die away from want of light; the scars resulting from their removal are covered with a new growth of wood, so that the trunk finally appears as if it had always been destitute of branches, to a great height. When all the buds develop normally and in due propor- tion, the plant, thus regularly built up, has a symmetrical appearance, as frequently happens with many herbs, and also with some of the cone-bearing trees, especially the balsam-fir. Latent Buds,—Often, however, many of the buds re- | main undeveloped either permanently or for a time. Many of the side-buds of most of our forest and fruit trees fail entirely to grow, while others make no progress until the summer succeeding their first appearance. When the active buds are destroyed, either by frosts or by pinching off, other buds that would else remain latent, are pushed into growth. In this way, trees whose young leaves are de- stroyed by spring frosts, cover themselves again after a Digitized by Microsoft® 264 HOW CROPS GROW. time with foliage. In this way, too, the gardener molds a straggling, ill-shaped shrub or plant into almost any form he chooses; for by removing branches and buds where they have grown in undue proportion, he not only-checks excess, but also calls forth development in the parts before suppressed, Adventitious or irregular Buds are produced from the stems as well as older roots of many plants, when they are mechanically injured during the growing season. The soft or red maple and the chestnut, when cut down, habitu- ally throw out buds and new stems from the stump, and the basket-willow is annually polled, or pollarded, to induce the growth of slender shoots from an old trunk. Elongation of Stems.—While roots extend chiefly at their extremities, we find the stem elongates equally, or nearly so, in all its contiguous parts, as is manifest from what has already been stated in illustration of its devel- opment from the bud. Besides the upright stem, there are a variety of prostrate and in part subterranean stems, which may be briefly no- ticed. Runners and Layers are stems that are sent out hori- zontally just above the soil, and coming in contact with the earth, take root, forming new plants, which may thence- forward grow independently. The gardener takes advan- tage of these stems to propagate certain plants. The strawberry furnishes the most familiar example of runners, while many of the young shoots of the currant fall to the ground and become layers. The runner is a somewhat peculiar stem. It issues horizontally, and usually bears but few or no leaves, The layer does not differ from an ordinary stem, except by the circumstance, often accident- al, of becoming prostrate. Many plants which usually send out no layers, are nevertheless artificially layered by bending their stems or branches to the ground, or by at= Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 265 taching to them a ball or pot of earth. The striking out of roots from the layer is in many cases facilitated by cut- ting half off, twisting, or otherwise wounding the stem at the point where it is buried in the soil. The ¢illering of wheat and other cereals, and of many grasses, is the spreading of the plant by layers. The first stems that appear from these plants ascend vertically, but, subsequently, other stems issue, whose growth is, for a time, nearly horizontal. They thus come in contact with the soil, and emit roots from their lower joints. From these again grow new stems and new roots in rapid suc- cession, so that a stool produced from a single kernel of winter wheat, having perfect freedom of growth, has been known to carry 50 or 60 grain-bearing culms. (Hallet, Jour. Roy. Soc. of Eng., 22, p. 372.) Subterranean Stems.—Of these there are three forms agriculturally interesting. They are usually thought to be roots, from the fact of existing below the surface of the soil. This circumstance is, however, quite accidental. The pods of the pea-nut ripen beneath the ground—the flower-stems lengthening and penetrating the earth as soon as the blossom falls; but peanuts are not by any means to be confounded with roots. Root-stocks,—As before remarked, true roots are desti- tute of buds, and, we may add, of leaves. This fact dis- tinguishes them from the so-called creeping-root, which ig a stem that extends just below the surface of the soil, emitting roots throughout its entire length. At intervals along these root-stocks, as they are appropriately named, scales are formed, which represent rudimentary leaves. In the axils of the scales may be traced the buds from which aérial stems proceed. Examples of the root-stock are very common. Among them we may mention the blood-root and pepper-root as abundant in the woods of the Northern and Middle States, and the quack-grass, 12 . Digitized by Microsoft® 266 HOW CROPS GROW. represented in fig. 46, which infests so many farms, Each node of the root-stock, being usually supplied with roots, and having latent buds, is ready to become an independ- ent growth the moment it is detached from its parent plant. In this way quack-grass becomes especially troub- Fig. 46. lesome to the farmer, for, within certain limits, the more he harrows the fields where it. has obtained a footing, the more does it spread and multiply. Suckers.—The rose, raspberry, and cherry, are examples of plants which send out subterranean branches, analogous to the root-stock. These coming to the surface, become atrial stems, and are then termed suckers. The Tubers of most agricultural plants are fleshy en- largements of the extremities of subterranean stems. Their eyes are the points where the buds exist, usually three together, and where minute scales — rudimentary leaves—may be observed. The common potato and arti- choke are instances of tubers. Tubers serve excellently for propagation. Each eye, or bud, may become a new plant. From the quantity of starch, ete., accumulated in them, they are of great importance as food. The number of tubers produced by a potato-plant appears to be in- creased by planting originally at a considerable depth, or by “hillmg up” earth around the base of the aérial stems during the early stages of its growth. Digitized by Microsoft® ~ THE VEGETATIVE ORGANS OF PLANTS. 267 Bulbs are the lower parts of stems, greatly thickened, the internodes Rens undeveloped, while the leaves—usu- ally sc each other, The bulb is, in Bui a fleshy, permanent ual usually in part or entirely subterranean. From its apex, the proper stem, the foliage, etc., proceed; while from its base, roots are sent out. The structural identity of the bulb with a bud is shown by the fact that the onion, which furnishes the commonest example of the bulb, often bears bulblets at the top of its stem, in place of flowers. In like manner, the axillary buds of the tiger-lily are thickened and fleshy, and fall off as bulblets to the ground, where they produce new plants. Srrucrure or THE Srem.—The stem is so complicated in its structural composition that to discuss it fully would occupy a volume. For our immediate purposes it is, however, only necessary to notice it very concisely. The rudimentary stem, as found in the seed, or the new- formed part of the maturer stem at the growing points just below the terminal buds, consists of cellular tissue, i. e., of an aggregate of rounded and cohering cells, which rapidly multiply during the vigorous growth of the plant. In some of the lower orders of vegetation, as in mush- rooms and lichens, the stem, if any exist, always preserves a purely cellular character; but in all flowering plants the original cellular tissue of the stem, as well as of the root, is shortly penetrated by vascular tissue, consisting of ducts or tubes, which result from the obliteration of the hori- zontal partitions of cell-tissue, and by wood-cells, which are many times longer than wide, and the walls of which are much thickened by internal deposition, \ These ducts and wood-cells, together with some other forms of cells, are usually found in close connection, and are arranged in bundles, which constitute the fibers of the stem. They are always disposed lengthwise in the stem and branches. They are found to some extent in the soft- Digitized by Microsoft® 268 HOW CROPS GROW. est herbaceous stems, while they constitute a large share of the trunks of most shrubs and trees. From the tough- ness which they possess, and the manner in which they are woven through the original cellular tissue, they give to the stem its solidity and strength. The flowering plants of temperate climates may be di- vided into two great classes, in consequence of important and obvious differences in the structure of their stems and seeds. These are, 1, Hndogenous or Monocotyledonous ; and, 2, Hxogenous or Dicotyledonous plants. As regards their stems, these two classes of plants differ in the ar- rangement of the vascular or woody tissue. Endogenous Plants are those whose stems enlarge by the formation of new wood in the interior, and not by the external growth of concentric layers. The seeds of endog- enous plants consist of a single piece—do not readily split into halves,—or, in botanical language, have but one cotyledon ; hence are called monocotyledonous. Indian corn, sugar cane, sorghum, wheat, oats, rye, barley, the onion, asparagus, and all the grasses, belong to this tribe of plants. If a stalk of maize, asparagus, or bamboo, be cut across, the bundles of ducts are seen disposed somewhat uni- c Fig. 47. formly throughout the section, though less abundantly to- wards the center. On splitting the fresh stalk lengthwise, the vascular bundles may be torn out like strings. At the nodes, where the stem branches, or where leaf-stalks are attached, the vascular bundles likewise divide and form a net-work, or pleeus. In a ripe maize-stalk which is exposed to circumstances favoring decay, the soft cell-tis- sue first suffers change and often quite disappears, leaving Digitized by Microsoft® THE V2GETATIVE ORGANS OF PLANTS. 269 the firmer vascular bundles unaltered in form. A portion of the base of such a stalk, cut lengthwise, is represented in figure 47, where are seen the duct-fibers arranged par- allel to each other in the internodes, and curiously inter- woven and branched at the nodes, either those, a@ and 2, from which roots issue, or that, c, which was clasped by the base of a leaf. The endogenous stem, as represented in the maize-stalk, has no well-defined bark that admits of being stripped off externally, and no separate central pith of soft cell-tissue free from vascular bundles. It, like the aérial portions of all flowering plants, is covered with a skin, or epidermis, composed usually of one or several layers of flattened cells, whose walls are thick, and far less penetrable to fluid than the delicate texture of the interior cell-tissue. The stem is denser and harder at the circumference than towards the center. This is due to the fact that the fibers are more numerous and older towards the outside of the stem. The newer fibers, as they continually form, grow in the inside of the stem, and hence the designation endog- enous, which in plain English means inside-grower. In consequence of this inner growth, the stems of most woody endogens, as the palms, after a time become so in- durated externally, that all lateral expansion ceases, and the stem increases only in height. It grows, nevertheless, internally, new fibers developing in the softer portions, until, in some cases, the tree dies because its interior is so closely packed with fibers that the formation of new ones, and the accompanying vital processes, become impossible. In herbaceous endogens the soft stem admits the indefi- nite growth of new vascular tissue. The stems of the grasses are hollow, except at the nodes. Those of the rushes have a central pith free from vascular tissue. The Minute Structure of the Endogenous Stem is ex- hibited in the accompanying cuts, which represent highly Digitized by Microsoft® 270 HOW CROPS GROW. magnified sections of a Vascular Bundle or fiber from the maize-stalk. As before remarked, the stem is composed of a ground-work of delicate cell-tissue, in which bundles of vascular tissue are distributed. Fig. 48 represents a cross section of one of these bundles, ¢, g, A, as well as of a portion of the surrounding cell-tissue, @, a. The latter consists of quite large cells, which, being but loosely packed together, have between them considerable inter- cellular spaces, 7 The vascular bundle itself is composed externally of narrow, thick-walled cells, of which those - nearest the exterior of the stem, 2, are termed bast-cells, as they correspond in character and position to the cells Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 271 of the bast or inner bark of our common trees; those nearest the centre of the stem, c, are wood-cells. In the maize stem, bast and wood-cells are quite alike, and are distinguished only by their position. In other plants, they are often unlike as regards length, thickness, and pli- ability, though still, for the most part, similar in form. Among the wood-cells we observe a number of ducts, d, e, J, and between these and the bast-cells is a delicate and transparent tissue, g, which is the cambizum—in which all the growth of the bundle goes on until it is complete. On a d ne Gorn fill ag WH UA i \ t i a | I mn either hand is seen a remarkably large duct, 0, 6, while the residue of the bundle is composed of long and rather thick-walled wood-cells. Our understanding of these parts will be greatly aided by a study of fig. 49, which represents a section made vertically through the bundle from ¢ to h, cutting the va- rious tissues and revealing more of their structure. In this the letters refer to the same parts as in the former cut: a, a, is the cell-tissue, enveloping the vascular bundle; the cells are observed to be much longer than wide, but are separated from each other at the ends as well as sides Digitized by Microsoft® Fig. 49. 272 HOW CROPS GROW. by an imperforate membrane. The wood and bast-cells, ¢, h, are seen to be long, narrow, thick-walled cells running obliquely to a point at either end. The wood-cells of oak, hickory, and the toughest woods, as well as the bast-cells of flax and hemp, are quite similar in form and appearance. The proper ducts of the stem are next in the order of our section. Of these there are several varieties, as ring-ducts, ad; spiral ducts, e; dotted ducts, f. These are continuous tubes produced by the resorption of the transverse mem- branes that once divided them into such cells as a, @, and they are thickened internally by ring-like, spiral, or punc- tate depositions of cellulose, (see fig. 32, p. 227.) Wood- cells that consist exclusively of cellulose are pliant and elastic. It is the deposition of lignin in their walls which renders them stiff and brittle. At g, the cambium tissue is observed to consist of deli- cate cylindrical cells. Among these, partial resorption of the separating membrane often occurs, so that they com- municate directly with each other through sieve-like parti- tions, and become continuous channels or ducts, (sieve-cells, p. 280.) The cambium is the seat of growth by cell-formation. Accordingly, when a vascular bundle has attained maturi- ty, it no longer possesses a cambium; the latter has grown away from it, has reproduced itself in originating a new vascular bundle, which, in case of the endogens, branches off from the present bundle, and with exogens, runs paral- lel with, and exterior to the latter. To complete our view of the vascular bundle, fig. 50 “represents a vertical section made at right angles to the, last, cutting two large ducts, 6,6; «, a, is cell-tissue; ¢,' c, are bast or wood-cells less thickened by interior deposi-| tion than those of fig. 49; d, isa ring and spiral duct; 8, 6, are large dotted ducts, which exhibit at g, g, the places where they were once crossed by the double membrane composing the ends of two adhering cells, by whose ab- Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 273 sorption and removal an uninterrupted tube has been formed. In these large dotted ducts there appears to be no direct communication with the surrounding cells through their sides. The dots or pits are simply very thin. points in the cell-wall, through which sap may soak or diffuse laterally, but not flow. When the cells become mature and cease growth, the pits often become pores by | : Na ‘ya | { ‘ Be } ( i K absorption of the membrane, so that the ducts thus enter into direct communication with each other. Exogenous plants are those whose stems continually enlarge in diameter by the formation of new tissue near the outside of the stem. They are outside-growers. Their seeds are usually made up of two loosely united parts, or cotyledons, wherefore they are designated dicotyledonous. All the forest trees of temperate climates, and, among agricultural plants, the bean, pea, clover, potato, beet, tur- nip, flax, ete., are exogens. In the exogenous stem the bundles of ducts and fibers that appear in the cell-tissue are always formed just within : Digitized by Microsoft® a Fig. 50. ———— 274 HOW CROPS GROW. the epidermis. They occur at first separately, as in the endogens, but instead of being scattered throughout the cell-tissue, are disposed in a circle. As they grow, they usually close up to a ring or zone of wood, which, within, incloses unaltered cell-tissue—the pith—and without, in shrubs and trees, is covered by rind. As the stem enlarges, new rings of fibers may be form- ed, but always outside of the older ones. In hard stems of slow growth the rings are close together and chiefly consist of very firm wood-cells. In the soft stems of herbs the cell-tissue preponderates, and the ducts and cells of the vascular zones are delicate. The hardening of herba- ceous stems which takes place as they become mature, is due to the increase and induration of the wood-cells and ducts. : The circular disposition of the fibers in the exogenous stem may be readily seen in a multitude of common plants. The potato tuber is a form of stem always accessible for observation. If a potato be cut across near the stem- end with a sharp knife, it is usually easy to identify upon the section a ring of vascular tissue, the general course of which is parallel to the circumference of the tuber except where it runs out to the surface in the eyes or buds, and in the narrow stem at whose extremity it grows. Ifa slice across a potato be soaked in solution of iodine for a few minutes, the vascular rings become strikingly apparent. In its active cambial cells, albuminoids are abundant, which assume a yellow tinge with iodine. The starch of the cell- tissue, on the other hand, becomes intensely blue, making the vascular tissue all the more evident. Since the structure of the root is quite similar to that of the stem, a section of the common bect as well as one of a branch from any tree of temperate latitudes may serve to illustrate the concentric arrangement of the vascular zones when they are multiplied in number. Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 275 Pith is the cell-tissue of the center of the stem. In young stems it is charged with juices; in older ones it often becomes dead and sapless. In many cases, especially when growth is active, it becomes broken and nearly obliterated, leaving a hollow stem, as in a rank pea-vine, or clover- stalk, or in a hollow potato. In the potato tuber the pith- cells are occupied. throughout with starch, although, as the coloration by iodine makes evident, the quantity of starch diminishes from the vascular zone towards the center of the tuber. The Rind, which, at first, consists of mere epidermis, or short, thick-walled cells, overlying soft cellular tissue, becomes penetrated with cells of unusual length and te- nacity, which, from their position in the plant, are often termed basé-cells. These, together with ducts of various kinds, all united firmly by their sides, constitute the so- called bast-fibers, which grow chiefly upon the interior of the rind, in close proximity to the wood. With their abundant development and with age, the rind becomes bark as it oceurs on shrubs and trees. The bast-cells give to the bark its peculiar toughness, and cause it to come off the stem in long and pliant strips. Bast-mats are made by weaving together strips of the inner bark of the Linden (bass or bast-wood) tree; and all the textile materials employed in making cloth and cord- age, with the exception of cotton, as flax,hemp, New Zea- land flax, etc., are bast-fibers. The leather-wood or moose- wood bark often employed for tying flour-bags, has bast- fibers of extraordinary tenacity. The external rind, like the interior pith, becomes sapless and dead in perennial plants, and after a longer or shorter period falls away. The outer bark of the grape separates in long shreds a year or two after its formation. On most forest trees the bark remains for several or many years. The expansion of the tree furrows the bark with numerous Digitized by Microsoft® 276 HOW CROPS GROW. and deep longitudinal rifts, and it gradually decays or drops away exteriorly as the newer bark forms within. Cork is one form which the epidermal cells assume on the stem of the cork oak, on the potato tuber, and many other plants. Pith Rays.— Those portions of the first-formed cell- tissue which were interposed between the young and orig- inally ununited wood-fibers remain, and connect the pith | with the rind. In hard stems they become flattened by the pressure of the fibers, and are readily seen in most kinds of wood when split lengthwise. They are especially conspicuous in the oak and maple, and form what is com- monly known as the silver-grain. The botanist terms them pith-rays or medullary rays. Fig. 51 exhibits a section of a bit of wood of the Red Pine, (Pinus picea,) magnified 200 di- ameters. The section is made tangential to the stem and length- wise of the wood-cells, four of ee which are in part represented, A ; Heels it cuts across the pith-rays, whose cell-structure and position in the wood are seen at m, n. Cambium of Exogens.—The growing part of the exog- enous stem is thus found between the wood and the bark, or rather between the fully formed wood and the mature bark. There is, in fact, no definite limit where wood ceases and bark begins, for they are connected by the cambial or formative tissue, from which, on the one hand, wood-fibers, and on the other, bast-fibers, or the tissues df the bark, rapidly develope. In the cambium, likewise, the pith-rays Digitized by Microsoft® t THE VEGETATIVE ORGANS OF PLANTS. 277 which connect the inner and outer parts of the stem, con- tinue their outward growth. In spring-time the new cells that form in the cambial region are very delicate and easily broken. For this rea- son the rind or bark may be stripped from the wood with- out difficulty. In autumn these cells become thickened and indurated, become, in fact, full-grown bast and wood- cells, so that to peel the bark off smoothly is impossible. Minute Structure of Exogenous Stems.—The accom- panying figure (52) will serve to convey an idea of the mi- nute structure of the elements of the exogenous stem. It Fig. 52. exhibits a highly magnified section lengthuise, through a young potato tuber. A, 0,is the rind; ¢,is the vascular ring; f, the pith. The outer cells of the rind are convert- ed into cork. They have become empty of sap and are nearly impervious to air and moisture. This corky-layer, a,* constitutes the thin coat or skin that may be so readily peeled off from a boiled potato. Whenever a potato is superficially wounded, even in winter time, the exposed part heals over by the formation of cork-cells. The cell- tissue of the rind consists at its center, }, of full-formed cells with delicate membranes which contain numerous and large starch grains. On either hand, as the rind ap- * The bracket, a, is much too long, and d is correspondingly too short in the cut. ‘ Digitized by Microsoft® 278 HOW CROPS GROW. proaches the corky-layer or the vascular ring, the cells are smaller, and contain smaller starch grains; either side of these are noticed cells containing no starch, but having nuclei, c, y. These nucleated cells are capable of multi- phenaa and they are situated where the growth of the tuber takes place. The rind, which makes a large part of the iach of the potato, increases in thickness by the formation of new cells within and with- out. Without, where it joins the corky skin, the latter likewise grows. Within, contiguous to the vascular zone, new ducts are formed. In a similar manner, the pith expands by formation of new cells, where it joins the vascular tissue. The latter consists, in our figure, of ring, spiral, and dotted ducts, ike those al- ready described as occurring in the maize-stalk. The delicate cambial cells, c, are in the region of most active growth. At this point new cells rap- idly develope, those to the right, in the figure, remaining plain cells and becom- ing loosely filled with starch; those to the left developing new ducts. In the slender, overground potato- stem, as in all the stems of most agricul- tural plants, the same relation of parts is to be observed, although the vascular and woody tissues often preponderate. Wood-cells are especially abundant in those stems that need strength for the fulfilment of their offices, and in them, especially in those of our trees, the structure is commonly more complicated. Perforation of Wood-Ceils in the Conifers.—In the wood of cone-bearing trees there are no proper ducts, such Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 279 as have been described. To answer the purpose of air and sap-channels, the wood-cells which constitute the con- centric rings of the old wood are constructed in a special manner, being provided laterally with visible pores, through which the contents of one cell may pass directly into those of its neighbors. Fig. 53, B, represents a por- tion of an isolated wood- cell of the Scotch Fir, (Pinus sylvestris,) mag- nified 200 diameters. Upon it are seen nearly circular disks, #, y, the structure of which, while the cell is young, is shown by a section through them length- wise. A exhibits such a section through the thickened walls of two contiguous and adhering cells. 2, in both A and B, shows a cavity be tween the two primary cell-walls; y is the nar- row part of the chan- nel, that remains while the membrane thickens around it. .This is seen in B, y, 48 a@ pore or opening in the cell. In 1 it appears closed because the section passes a little to one side of the pore. In the next figure, (54,) representing a transverse sec- tion of the spring wood of the same tree magnified 300 diameters, the structure and the gradual formation of Digitized by Microsoft® Fig, 54. 280 HOW CROPS GROW. ‘these pore disks is made evident. The section, likewise, gives an instructive illustration of the general character of the simplest kind of wood. R, are the young cells of the rind; C, is the cambium, where cell multiplication goes on; W, is the wood, whose cells are more developed the older they are, i.e., the more distant from the cam- bium, as is seen from their figure and the thickness of their walls. At a is shown the disk in its earliest stage; b and ¢ exhibit it in a more advanced growth before it be- comes a pore, the original cell-wall being still in place. At d,in the finished wood-cells, the disk has become a pore, the primary membrane has been absorbed, and a free channel made between the two cells. The dotted lines at d lead out laterally to two concentric circles, which repre- sent the disk-pore seen flatwise, as in fig. 53. At ¢, the section passes through the new annual ring into the au- tumn wood of the preceding year. Sieve-cells or sieve-ducis,—The spiral, ring, and dotted ducts and porous wood-cells already noticed, appear only in the older parts of the vascular bundles, and although they are occupied with sap at times when the stem is sur- charged with water, they are ordinarily filled with air alone. The real transmission of the nutritive juices of the growing plant, so far as it goes on through actual tubes, is now admitted to proceed in an independent set of ducts, the so-called sieve-cells, which are usually near to, and originate from the cambium. These are extremely deli- cate, elongated cells, whose transverse or lateral walls are perforated, sieve-fashion, (by absorption of the original membrane,) so as to establish direct communication from one to another, and this occurs while they are yet charged with juices and at a time when the other ducts are occu- pied with air alone. These sieve-ducts are believed to be the channels through which the matters organized in the foliage most abundantly pass in their downward move- ment to nourish the stem and root. Fig. 55 represents Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 281 the sieve-cells in the overground stem of the potato; A, B, cross-section of parts of vascular bundle—4A, exterior part towards rind; ZB, interior portion next to pith—a, a, cell-tissue inclosing the smaller sieve- cells, A, £B, which contain sap turbid with minute gran- ules; 6, cambium cells; ¢, wood-cells (which are absent in the potato tuber ;) d, ducts intermingled with wood-cells. C represents a section lengthwise of the sieve-ducts; and D, more highly magni- fied,exhibits the fine- ly perforated, trans- verse partitions, through which the liquid contents free- ly pass. Milk Ducts.—Be- sides the ducts al- ready described, there is, in many plants, a system of irregularly branched channels containing a milky juice, as in the sweet potato, dandelion, milk- weed, etc. These milk-ducts, together with many other details of stem-structure, are imperfectly understood, and require no further notice in this treatise. - Herbaceous Stems.—Annual stems of the exogenous Digitized by Microsoft® 282 HOW CROPS GROW. kind, whose growth is entirely arrested by winter, consist usually of a single ring of woody tissue with interior pith and surrounding bark. Often, however, the zone of wood is thin, and possesses but little solidity, while the chief part of the stem is made up of cell-tissue, so that the stem is herbaceous. Woody Stems.—Perennial exogenous stems consist, in temperate climates, of a series of rings or zones, corre-, sponding in number with that of the years during which their growth has been progressing. The stems of our shrubs and trees, especially after the first few years of growth, consist, for the most part, of woody tissue, the pro- portion of cell-tissue being very small. The annual cessation of growth which occurs at the approach of winter, is marked by the formation of smaller or finer wood-cells, as shown in fig. 54, while the vigorous renewal of activity in the cambium at spring-time is ex- hibited by the growth of larger cells, and in many kinds of wood in the production of ducts, which, as in the oak, are visible to the eye at the interior of the annual layers. Sap-wood and Heart-wood.—The living processes in perennial stems, while proceeding with most force in the cambium, are not confined to that locality, but go on toa considerable depth in the wood. Except at the cambial layer, however, these processes consist not in the forma- tion of new cells, nor the enlargement of those once form- ed—not properly in growth—but in the transmission of sap and the deposition of organized matter on the interior of the wood-cells. In consequence of this deposition the inner or heart-wood of many of our forest trees becomes much denser in texture and more durable for industrial purposes. It then acquires a color different from the outer or sap-wood (alburnum,) becomes brown in most cases, though it is yellow in the barberry and red in the red ecdar, Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 283 The final result of the filling up of the cells of the heart- wood is to make this part of the stem almost or quite im- passable to sap, so that the interior wood may be removed by decay without disturbing the vigor of the tree. Passage of Sap through the Stem.—The stem, besides supporting the foliage, flowers, and fruit, has also a most important office in admitting the passage upward to these organs, of the water and mineral matters which enter the plant by the roots. Similarly, it allows the downward transfer to the roots, of substances gathered by the foliage from the atmosphere. To this and other topics connected with the ascent and descent of the sap we shall hereafter recur. The stem constitutes the chief part by weight of many plants, especially of forest trees, and serves the most im- portant uses in agriculture, as well as in a thousand other industries. § 3, LEAVES. These most important organs issue from the stem, are at first folded curiously together in the bud, and after- wards expand so as to present a great amount of surface to the air and light. The leaf consists of a thin membrane of cell-tissue, ar- ranged upon a skeleton or net-work of fibers and ducts. It is directly connected with, and apparently proceeds from, the cambial-layer of the stem, of which it may, ac- cordingly, be considered an expansion. In certain plants, as the cactus (prickly pear), there scarcely exist any leaves, or, if any occur, they do not differ, except in external form, from the stems. Many of these plants, above ground are in form, all stem, while in structure and function, they are all leaf. Digitized by Microsoft® 284 HOW CROPS GROW. In the grasses, although the stem and leaf are distinguish- able in shape, they are but little unlike in other external characters. : In forest trees, we find the most obvious and striking differences between the stem and leaves. Green Color of Leaves.—A peculiarity most character- istic of the leaf, so long as it is in vigorous discharge of its proper vegetative activities, is the possession of a green color. This color is also proper in most cases to the young bark of the stem, a fact further indicating the connection between these parts, or rather demonstrating their identity of origin and function, for it is true, not only in the case of the cactuses, but also in that of all other young plants, that the green (young) stems perform, to some extent, the same offices as the leaves. The loss of green color that occurs in autumn, in case of the foliage of our deciduous trees, or on the maturing of the plant in case of the cereal grains, is connected with the cessation of growth and death of the leaf. There are plants whose foliage has a red, brown, white, or other than a green color during the period of active growth. Many of these are cultivated by florists for ornamental purposes. The cells of these color- ed leaves are by no means destitute of chlorophyll, as is shown by mi- croscopic examination, though this substance is associated with other coloring matters which mask its green tint. Structure of Leaves.—While in shape, size, modes of arrangement upon, and attachment to the stem, we find among leaves no end of diversity, there is great simplicity in the matter of their internal structure. The whole surface of the leaf, on both sides, is covered with epidermis, a coating, which, in many cases, may be readily stripped off the leaf, and consists of thick-walled cells, which are, for the most part, devoid of liquid con- tents, except when very young. (2, &, tig. 56.) The accompanying figure (56) represents the appearance of a bit of bean-leaf as seen on asection from the upper to the lower surface and highly magnified. : Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 285 Below the upper epidermis, there often occur one or more layers of oblong cells, whose sides are in close con- tact, and which are arranged endwise, with reference to the flat of the leaf. Below these, down to the lower epi- dermis, for one-half to three-quarters of the thickness of the leaf, the cells are commonly spherical or irregular in figure and arrangement, and more loosely disposed, with numerous and large interspaces. The interspaces among the leaf-cells are occupied with air, which is also, in most cases, the only con- tent of the epidermal cells. The active cells of the leaf contain some or all of the various proximate principles which have been already noticed, and in addition the coloring matter of vegetation, —the so-called chlorophyll, or leaf-green, p. 109. Under the microscope, this sub- stance is commonly seen in the form of minute grains attached to the walls of the cells, as in fig. 56, or coating starch granules, or else floating free in the cell-sap. The structure of the veins or ribs of the leaf is similar to that of the vascular bundles or fibers of the stem, of which they are branches. At a, fig. 56, is seen the cross section of a vein in the bean-leaf. The epidermis, while often smooth, is frequently beset with hairs or glands, as seen in the figure. These are va- riously shaped cells, sometimes empty, sometimes, as in the nettle, filled with an acid liquid. Their office is little understood. Leaf-Pores.—The epidermis is further provided with a vast number of curious “breathing pores,” or stomata, by means of which the intercellular spaces in the interior of the leaf may be brought into direct communication with the outer atmosphere. Each of these stomata consists Digitized by Microsoft® 286 IIOW CROPS GROW. usually of two curved cells, which are disposed toward each other nearly like the two sides of the letter O, or like the halves of an elliptical carriage-spring, (figs. 52 and 53), , L on The opening between them se / is an actual orifice in the | sy skin of the leaf. The size of the orifice is, however, con- stantly changing, as the at- mosphere becomes drier or more moist, and as the sun- light acts more or less in- tensely on its surface. In moist air, they curve out- wards, and the aperture is enlarged; in dry air, they straighten and shut together like the springs of a heavily loaded carriage, and nearly or entirely close the entrance. The effect of strong light is to enlarge their orifices. In fig. 56 is represented a section through the shorter diameter of a pore on the under surface of a bean-leaf. The air-space within it is shaded black. Unlike the other epidermal cells, those of the leaf-pore contain grains of chlorophyll. : Fig. 57 represents a portion of the epidermis of the upper surface of a potato-leaf, and fig. 58 a similar portion of the under surface of the same leaf, magnified 200 diameters. In both figures are seen the open pores between the semi-elliptical cells. The outline of the other epidermal cells is marked by irregular double lines. The round bodies in the cells of the pores are starch-grains, often present in these cells, when not existing in any other part of the leaf. The stomata are with few ex- ceptions altogether wanting on the submerged leaves of aquatic plants. On floating leaves they oceur, but only on the upper surface. Thus, as a rule, they are not found in contact with liquid water. On the other hand, they are either absent from, or comparatively few in Fig. 57. Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 287 number upon, the upper surfaces of land plants, which are exposed to the heat of the sun, while they exist in great numbers on the lower sides of all green leaves. In number and size, they vary remarkably. Some leaves possess but 800 to the square inch, while others have as many as 170,000 to that amount of surface. About 100,000 may be counted on an average-sized apple-leaf. In general, they are largest and most numerous on plants which be- long in damp, and shaded situations, and then exist on both sides of the leaf. The epidermis itself is most dense—consists of thick- walled cells and several layers of them—in case of leaves which belong to the vegetation of sandy soils in hot cli- mates. Often it is impregnated with wax on its upper surface, and is thereby made almost impenetrable to moist- ure. On the other hand, in rapidly growing plants adapt- ed to moist situations, the epidermis is thin and delicate. Exhalation of Water-Vapor.—A considerable loss of water goes on from the leaves of growing plants when they are freely exposed to the atmosphere. The water thus lost exhales in the form of invisible vapor. The quantity of water exhaled from any plant may be easily ascertained, provided it is growing in a pot of glazed earthen, or other impervious material. A metal or glass cover is cemented air-tight to the rim of the vessel, and around the stem of the plant. The cover has an opening with a cork, through which weighed quantities of water are added from time to time, as required. The amount of exhalation during any given interval of time is learned with a close approach to accuracy by simply noting the loss of weight which the plant and pot together suffer. Hales, who first experimented in this manner, found that a sunflower, whose foliage had an aggregate surface of 89 square feet, gave off 3 lbs. of water in a space of 24 hours. -Knop observed a maize-plant to exhale, between Digitized by Microsoft® 288 HOW CROPS GROW. 4 May 22d and September 4th, no less than 36 times its weight of water. Exhalation is not a regular or uniform process, but varies with a number of circumstances and conditions. It de- pends largely upon the dryness and temperature of the air. When the air is in the state most favorable to evaporation, the loss from the plant is rapid and large. When the air is saturated with moisture, as during dewy nights or rainy weather, then exhalation is nearly or totally checked. The temperature of the soil, and even its chemical com- position, the condition of the leaf as to its age, texture, and number of stomata, likewise affect the rate of ex- halation. Exhalation is a process not necessary to the life of the plant, since it may be suppressed or be reduced to a minimum, as ina Wardian case or fernery, without evident influence on growth. Neither is it detrimental, unless the loss is greater than the supply. If water escapes from the leaves faster than it enters the roots, the plant wilts; and if this disturbance goes on too far, it dies. Exhalation ordinarily proceeds to a large extent from the surface of the epidermal cells. Although the cavities of these cells are chiefly occupied with air, their thickened walls transmit outward the water which is supplied to the interior of the leaf through the cambial ducts. Other- wise the escape of vapor occurs through the stomata, These pores appear to have the function of regulating the exhala: tion, to a great extent, by their property of closing, when the air, from its dryness, favors rapid evaporation. They are, in fact, self-acting valves which protect the plant from too sudden and rapid Joss of water. Access of Air to the Interior of the Plant.—Not only does the leaf allow the escape of vapor of water, but it admits of the entrance and exit of gaseous bodies. Digitized by Microsoft® THE VEGETATIVE ORGANS OF PLANTS. 289 The particles of atmospheric air have easy access to the interior of all leaves, however dense and close their epi- dermis may be, however few or small their stomata. All leaves are actively engaged in absorbing and exhaling cer- tain gaseous ingredients of the atmosphere during the whole of their healthy existence. The entire plant is, in fact, pervious to air through the stomata of the leaves. These com- municate with the intercellular \, spaces of the leaf, which are, in lj general, occupied exclusively with i air, and these again connect with the ducts which ramify throughout the veins of the leaf and branch —— from the vascular bundles of the ——. stem. In the bark or epidermis of woody stems, as Hales long ago discovered, pores or cracks exist, through which the air has communi- cation with the longitudinal ducts. These facts admit of demonstration by simple means. Sachs employs for this pur- pose an apparatus consisting of a short wide tube of glass, B, fig. 59, to which is adapted, below, by a tightly fitting cork, a bent glass tube. The stem of a leaf is passed through I a cork which is then secured air-tight in the ( ( y AS other opening of the wide tube, the leaf itself GG EY nla g Sy . being included in the latter, and the joints are made air-tight by smearing with tallow. : The whole is then placed in a glass jar con- Fig. 59. taining enough water to cover the projecting leaf-stem, and mercury is quickly poured into the open end of the bent tube, so as nearly to fill the " Jatter. The pressure of the column of this dense liquid immediately forces air into the stomata of the leaf, and a corresponding quantity is forced on through the intercellular spaces and through the vein-ducts into the ducts of the leaf-stem, whence it issues in fine bubbles at S. It is even casy in many cases to demonstrate the permeability of the leaf to air by immersing it in water, and, taking the leaf-stem between the lips, produce a current by blowing. In this case the air escapes from the stomata. The air-passages of the stem may be shown by a similar arrangement, 12 Digitized by Microsoft® 290 HOW CROPS GROW. or in many instances, as, for example, with a stalk of maize, by simply immersing one end in water and blowing into the other. On the contrary, roots are destitute of any visible pores, and are not pervious to external air or vapor in the sense that leaves and young stems are. The air passages in the plant correspond roughly to the mouth, throat, and breathing cavities of the animal. We have, as yet, merely noticed the direct communication of these passages with the external air by means of micros- copically visible openings. But the cells which are not visibly porous readily allow the access and egress of wa- ter and of gases by osmose. To the mode in which this is effected we shall recur on subsequent pages, (pp. 854- 366.) The Offices of Foliage are to put the plant in commu- nication with the atmosphere and with the sun. On the one hand it permits, and to a certain degree regulates, the escape of the water which is continually pumped into the plant by its roots, and on the other hand it absorbs from the air, which freely penetrates it, certain gases which “furnish the principal materials for the organization of vege-- table matter. We have seen that the plant consists of elements, some of which are volatile at the heat of ordina- ry fires, while others are fixed at this temperature. When a plant is burned, the former, to the extent of 90-99 per cent of the plant, are converted into gases, the latter re- main as ashes, The reconstruction of vegetation from the products of its combustion (or decay) is, in its simplest phase, the gathering by a new plant of the ashes from the soil through its roots, and of these gases from the air by its leaves, and the compounding of these comparatively sim- ple substances into the highly complex ingredients of the vegetable organism. Of this work the leaves have by far the larger share to perform; hence the extent of their sur- face and their indispensability to the welfare of the plant, Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 291 The assimilation of carbon in the plant is most inti- mately connected with the chlorophyll, which has been no- ticed as the green coloring matter of the leaf, and depends also upon the solar rays. CHAPTER IV. REPRODUCTIVE ORGANS OF PLANTS. g 2. THE FLOWER. The onward growth of the stem or of its branches is not necessarily limited, until from the terminal buds, in- stead of leaves, only FLowErs unfold. When this happens, as is the case with most annual and biennial plants, raised. on the farm or in the garden, the vegetative energy has usu- ally attained its fullest development, and the reproductive function begins to prepare for the death of the individual by providing seeds which shall perpetuate the species. There is often at first no apparent difference between the leaf-buds and flower-buds, but commonly in the later stages of their growth, the latter are to be readily dis- tinguished from the former by their greater size, and by peculiar shape or color. The Flower is a short branch, bearing a collection of organs, which, though usually having little resemblance to foliage, may be considered as leaves, more or less mod- ified in form, color, and office. The flower commonly presents four different sets of or- gans, viz., Calyx, Corolla, Stamens, and FPistils, and is then said to be complete, as in case of the apple, potato, Digitized by Microsoft® 292 HOW CROPS GROW. and many common plants. Fig. 60 represents the com- plete flower of the Fuchsia, or ladies’ ear-drop, now uni- versally cultivated. In fig. 61 the same is shown in section. The Calyx, (cup,) ev, is the outermost floral envelope. Its color is red or white in the Fuchsia, though generally it is green, When it consists of several distinct leaves, . they are called sepals. The calyx is frequently small and inconspicuous. In some cases it falls away as the flower opens. In the Fuchsia it firm- ly adheres at its m base to the seed- \ vessel, and is divid- ed into four lobes. The Corolla, (crown,) ¢, or ca, is one or several series of leaves which are situated within the calyx. It is usually of some other than a green color, (in the Fuchsia, purple, etc.,) often has marked peculiarities of form and great delicacy of structure, and thus chiefly gives beauty to the flower. When the corolla is divided into separate leaves, these are termed petals. The Fuchsia has four petals, which are attached to the calyx-tube. Fig. 61. The Stamens, s, in fig’s 60 and 61, are generally slender, thread-like organs, terminated by an oblong sack, the an- ther, which, when the flower attains its full growth, dis- charges a fine yellow er brown dust, the so-ealled pollen. Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 293 The forms of anthers, as well as of the grains of pollen, vary with nearly every kind of plant. The yellow pollen of pine and spruce trees is not infrequently transported by the wind to a great distance, and when brought down by rain in considerable quantities, has been mistaken for sulphur. The Pistil, p, in fig’s 60 and 61, or pistils, occupy the center of the perfect flower. They are exceedingly va- rious in form, but always have at their base the seed-ves- sels or ovaries, ov, in which are found the ovudes (little eggs) or rudimentary seeds. The summit of the pistil is destitute of the epidermis which covers all other parts of the plant, and is termed the stigma, st. As has been remarked, the floral organs may be consid- ered to be modified leaves; or rather, all the appendages of the stem—the leaves and the parts of the flower to- gether—are different developments of one fundamental organ. The justness of this idea is sustained by the transforma- tions which are often observed. The rose in its natural state has a corolla consisting of five petals, but has a multitude of stamens and pistils. In arich soil, or as the effect of those agencies which are united in “cultivation,” nearly all the pistils and stamens lose their reproductive function and proper structure, and revert to petals; hence the flower becomes double. The tulip, poppy, and numerous garden-flowers, illustrate this interesting metamorphosis, and in these flowers we may often see at once the change in various stages intermediate between the perfect petal and the unaltered pistil. On the other hand, the reversion of all the floral organs into ordinary green leaves has been observed not’ infre- quently, in case of the rose, white clover, and other plants. i While the complete flower consists of the four sets of organs above described, only the stamens and pistils are essential to the production of seed. The latter, accord- Digitized by Microsoft® 294 HOW CROPS GROW. ingly, constitute a perfect flower even in the absence of calyx and corolla. The flower of buckwheat has no corolla, but a white or pinkish calyx. The grasses have flowers in which calyx and corolla are represented by scale-like leaves, which, as the plants ma- ture, become chaff. In various plants the stamens and pistils are borne in separate flowers. Such are called moncecious plants, of which the birch and oak, maize, melon, squash, cucumber, and oftentimes the strawberry, are examples. In case of maize, the staminate flowers are the “ tas- sels” at the summit of the stalk; the pistillate flowers are the young ears, the pistils themselves being the “ silk,” each fiber of which has an ovary at its base, that, if fer- tilized, developes to a kernel. Diccious plants are those which bear the staminate (male, or sterile) flowers and the pistillate (female, or fer- tile) flowers on different individuals; the willow tree, the hop-vine, and hemp, are of this kind. Fertilization and Fructification.—The grand function of the flower is fructification. For this purpose the pollen must fall upon or be carried by wind, insects, or other agen- cies, to the naked tip of the pistil. Thus situated, each pollen-grain sends out a slender tube of microscopic diam- eter, which penetrates the interior of the pistil until it en- ters the seed-sack and comes in contact with the ovule or rudimentary seed. This contact being established, the ovule is fertilized and begins to grow. Thenceforward the corolla and stamens usually wither, while the base of the pistil and the included ovules rapidly increase in size until the seeds are ripe, when the seed-vessel falls to the ground or else opens and releases its contents. Fig. 62 exhibits the process of fertilization as observed in a plant allied to buckwheat, viz., the Polygonum con- Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 295 volvulus. The cut represents a magnified section length- wise through the short pistil; a, is the stigma or summit of the pistil; 6, are grains of pollen; ¢, are pollen tubes that have penetrated into the sced- ; vessel which forms the base of the pistil; one has entered the mouth of the rudimentary seed, gy, and reached the embryo sack, e, within which it causes the development of a germ; d, represents the interior wall of the seed-vessel; A, the base of the seed and its attachment to the seed-vessel. Darwin has shown that certain plants, which have pistils and stamens in the same flower, are incapable of self-fertilization, and depend upon in- sects to carry pollen to their stigmas. Such are many Orchids. Artificial Fecundation has been proposed by Hooibrenk, in Belgium, as a means of increasing the yield of certain crops. Hooi- brenk’s plan of agitating the heads of grain at the time when the pollen is ripe, in order to ensure its distribution, which is done by two men traversing the field carrying a rope between them so as to lightly brush over the heads, appears to have been found very useful in some cases, though in many trials no good effects have followed its application. We must therefore conclude that agitation by the winds and the good offices of insects commonly render artificial assistance in the fecundating process en- tirely superfluous. Mybridizing.—As the union of the sexes of different kinds of animals sometimes results in the birth of a hybrid, so among plants, the ovules of one kind may be fertilized by the pollen of another, and the seed thus developed, in its growth, produces a hybrid plant. In both the animal | Ay Fig. 62. Digitized by Microsoft® 296 HOW CROPS GROW. and vegetable kingdoms the limits within which hybridiza- tion is possible appear to be very narrow. It is only be- tween closely allied species that fecundation can take place. Wheat, oats, and barley, show no tendency to “mix”; the pollen of one of these similar plants being incapable of fertilizing the ovules of the others. In flower and fruit-culture, hybridization is practised or attempted, as a means of producing new kinds. Thus the celebrated Rogers’ Seedling Grapes are believed to be hy- brids between the European grape, Vitis vinifera, and the allied but distinct Vitis labrusca, of North America. Hybridization between plants is effected, if at all, by removing from the flower of one kind, the stamens before they shed their pollen, and, dusting the summit of the pistil with pollen from another kind. The mixing of different varieties, as commonly happens among maize, melons, ete., is not properly hybridization, this word being used in the long-established sense. We are thus led to brief notice of the meaning of the terms species and variety, and of the distinctions employed in botanical classification. Species.—The idea of species as distinct from variety which has been held by most scientific authorities hither- to, is based primarily on the faculty of continued repro- duction. The horse is a species comprising many vari- eties. Any two of these varieties by sexual union may propagate the species. The same is true of the ass. The horse and the ass by sexual union produce a hybrid—the mule,—but the sexual union of mules is without result. They cannot continue the mule as a distinct kind of ani- mal—as a species. Among animals a species therefore com- prises all those individuals which are related by common origin or fraternity, and which are capable of sexual. fer- tility. This conception involves original and permanent differences between different species. Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 297 Species, therefore, cannot change any of their essential characters, those characters which are hence termed specific. Varieties.—Individuals of the same species differ. In fact, no two individuals are quite alike. Circumstances of temperature, food, and habits of life, increase these differ- ences, and varieties originate when such differences assume a comparative permanence and fixity. But as external conditions cause variation away from any particular rep- resentative of a species, so they may cause variation back again to the original, and although variation may take a seemingly wide range, its bounds are fixed and do not touch specific characters. The causes that produce varieties are numerous, but in many cases their nature and their mode of action is diffi- cult or impossible to understand. The influence of scarcity or abundance of nutriment we can easily comprehend may dwarf a plant or lead to the production of a giant indi- vidual; but how, in some cases, the peculiarities thus im- pressed upon individuals acquire permanence and are transmitted to subsequent generations, while in others they disappear, is beyond explanation. Among plants, varieties may often be perpetuated by the seed. This is true of our cereal and leguminons plants, which reproduce their kind with striking regulari- ty. Other plants cannot be or are not reproduced unalter- ed by the seed, but are continued in the possession of their peculiarities by cuttings, layers, and grafts. Here the in- dividual plant is in a sense divided and multiplied. The species is propagated, but not reproduced. The fact that the seeds of a potato, a grape, an apple, or pear, cannot be depended upon to reproduce the variety, may perhaps be more commonly due to unavoidable contact of pollen from other varieties, than to inability of the mother plant to perpetuate its peculiarities. That such inability often exists, is, however, well established, and is, in general, most obvious in case of varieties that have to the greatest 13* ; Digitized by Microsoft® 298 HOW CROPS GROW. degree departed from the original specific type. Thus nature puts the same limit to variation within a species that she has established against the mixing of species, Darwin’s Hypothesis, which is now accepted by many naturalists, is to the effect that species, as above defined, do not exist, but that new kinds (so-called species) of ani- mals and plants may arise by variation, and that all exist- ing animals and plants may have developed by a process of “natural selection” from one original type. Our ob- ject here is not to discuss this intricate question, but sim- ply to put the reader in possession of the meaning attach- ed to the terms currently employed in science—terms which must long continue in use and which are necessarily found in these pages.* Genus, (plural Genera.)——In the language of anti-Dar- winianism, any set of oaks that are capable of reproducing their kind by seed, but cannot mix their seed with other oaks, constitute a species. Thus, the white oak is one species, the red oak is another, the water oak is a third, the live oak a fourth, and so on. All the oaks, white, red, ete., taken together, form a group which has a series of characters in common that distinguishes them from all other trees and plants. Such a group of species is called a genus. Families or Orders, in botanical language, are groups of genera that agree in certain particulars. Thus the sev- eral plants well-known as mallows, hollyhock, okra, and cotton, are representatives of as many different genera. They all agree in a number of points, especially as regards the structure of their fruit. They are accordingly group- ed together into a natural family or order, which differs from all others. Classes, Series, and Classification.— Classes are groups * Yor a masterly statement of the facts and evidence bearing on these points, which are of the greatest importance to the agriculturist, see Darwin's works “On the Origin of Species,” and ‘‘On the Variation of Animals‘and Plants under Domestication.” Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 299 of orders, and Series are groups of classes. In botanical classification as now universally employed—classification after the Natural System—all plants are separated into two series, as follows: 1. Plowering Plants (Phanogums) which produce flowers and seeds with embryos, and 2. Plowerless Plants (Cryptogams) that have no proper flowers, and are reproduced by spores which are in most cases single cells. This series includes Ferns, Horse-tails, Mosses, Liverworts, Lichens, Sea-weeds, Mushrooms, and Molds. The use of classification is to give precision to our no- tions and distinctions, and to facilitate the using and ac- quisition of knowledge. Series, classes, orders, genera, species, and varicties, are as valuable to the naturalist as pigeon holes are to the accountant, or shelves and draw- ers to the merchant. Botanical Nomenclature.—so, too, the Latin or Greek names which botanists employ are essential for the discrim- ination of plants, being equally reccived in all countries, and belonging to all languages where science has a home. They are made necessary not only by the confusion of tongues, but by confusions in each vernacular. Botanical usage requires for cach plant two names, one to specify the genus, another to indicate the species. Thus all oaks are designated by the Latin word Quercus, while the red oak is Quercus rubra, the white oak is Quercus alba, the live oak is Quercus virens, ete. The designation of certain important families of plants is derived from a peculiarity in the form or arrangement of the flower. Thus the pulse family, comprising the bean, pea, and vetch, as well as lucern and clover, are called Papilionaceovs plants, from the resemblance of their flowers to a butterfly, (Latin, papédio), Again, the mustard family, including the radish, turnip, cabbage, wa- Digitized by Microsoft® 300 HOW CROPS GROW. ter-cress, etc., are termed Cruciferous plants, because their flowers have four petals arranged like the four arms of a cross, (Latin, crza). The flowers of a large natural order of plants are ar- ranged side by side, often in great numbers, on the expand- ‘ed extremity of the flower-stem. Examples are the thistle, dandelion, sun-flower, artichoke, China-aster, etc., which, from bearing such compound heads, are called Composite plants. The Coniferous (cone-bearing) plants comprise the pines, larches, hemlocks, etc., whose flowers are arranged in conical receptacles. The flowers of the carrot, parsnip, and caraway, are ar- ranged at the extremities of stalks which radiate from a central stem like the arms of an umbrella; hence they are called Umbelliferous plants, (from wmbel, Latin, for little screen). § 2, THE FRUIT Tue Fruir comprises the seed-vessel and the seed, to- gether with their various appendages. Tur SEED-VESSEL, consisting of the base of the pistil in its matured state, exhibits a great variety of forms and characters, which serve, chiefly, to define the different kinds of Fruits. Of these we shall only adduce such as are of common occurrence and belong to the farm. The Nut has a hard, leathery or bony shell, that does not open spontaneously. Examples are the acorn, chest- nut, beech-nut, and hazel-nut. The cup of the acorn and the bur of the others is a sort of fleshy calyx. The Stone-fruit or Drupe is a nut enveloped by a fleshy or leathery coating, like the peach, cherry, and plum, Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 301 also the butternut and hickory-nut. Raspberries and blackberries are clusters of small drupes. Pome is a term applied to fruits like the apple and pear, the core of which is the true seed-vessel, originally belonging to the pistil, while the often edible flesh is the enormously enlarged and thickened calyx, whose withered tips are always to be found at the end opposite the stem. The Berry is a mauy-seeded fruit of which the entire seed-vessel becomes thick and soft, as the grape, currant, tomato, and huckleberry. Gourd fruits have externally a hard rind, but are fleshy in the interior. The melon, squash, and cucumber, are of this kind. The Akene is a fruit containing a single seed which does not separate from its dry envelope. The so-called seeds of the composite plants, for example the sun-flower, thistle, and dandelion, are akenes. On removing the outer husk or seed-vessel we find within the true seed. Many akenes are furnished with a pappus, a downy or hairy appendage, as seen in the thistle, which enables the seed to float and be carried about in the wind. The fruit or grain of buck- wheat is akene-like. ; The Grains are properly fruits. Wheat and maize con- sist of the seed and the seed-vessel closely united. When these grains are ground, the bran that comes off is the seed-vessel together with the outer coatings of the seed. Barley-grain, in addition to the seed-vessel, has the petals of the flower or inner chaff, and oats have, besides these, the calyx or outer chaff adhering to the seed. Pod is the name properly applied to any dry seed-ves- sel which opens and scatters its seeds when ripe. Several kinds have received special designations ; of these we need only notice one. The Legume is a pod, like that of the bean, which splits into two halves, along whose inner edges seeds are Digitized by Microsoft® 302 HOW CROPS GROW. borne. The pulse family, or papilionaceous plants, are also termed leguminous from the form of their fruit. Tue SEED, or ripened ovule, is borne on a stalk which connects it with the seed-vessel. Through this stalk it is supplied with nutriment while growing. When matured and detached, a scar commonly indicates the point of former connection. The seed has usually two distinct coats or integuments. The outer one is often hard, and is generally smooth. In the case of cotton-seed it is covered with the valuable cot- ton fiber. The second coat is commonly thin and delicate. The Kernel lies within the integuments. In many cases it consists exclusively of the embryo, or rudimentary plant. In others it contains, besides the embryo, what has received the name of endosperm. The Endosperm forms the chief bulk of all the grains. If we cut a seed of maize in two lengthwise, we observe ex- tending from the point where it was attached to the cob the soft “chit,” 5, fig. 63, which is the embryo, to be pres- ently noticed. The remainder of the kernel, a, is endo- sperm; the latter, therefore, yields in great part the flour or meal which is so important a part of the food of man and animals. The endosperm is intended for the support of the young plant as it developes from the embryo, before it is capable of depending on the soil and atmosphere for sustenance. It is not, however, an indispensable part of the seed, and may be entirely removed from it, without thereby prevent- ing the growth of a new plant. The Embryo or Germ is the essential and most import- ant portion of the seed. It is, in fact, a ready-formed plant in miniature, and has its root, stem, leaves, and a bud, although these organs are often as undeveloped in form as they are in size. © As above mentioned, the chit of the seeds of maize and Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 303 the other grains is the embryo. Its form is with difficulty distinguishable in the dry seeds, but when they have been soaked for several days in water, it is readily removed from the accompanying endosperm, and plainly exhibits its three parts, viz, the radicle, the plumule, and the cotyledon. In fig. 63 is represented the embryo of maize. In A and B it is seen in section imbedded in the endosperm. | C exhibits the detached embryo. The Radicle, 7, is the rootlet of the seed-plant, or rather the point from which downward growth proceeds, from which the first true roots are produced. The Phunile, c, is the ascending axis of the plant, the central bud, out of which the stem with new leaves, flowers, etc., is developed. The Cotyledon, b, is in structure a ready-formed leaf, which clasps the plumule in the embryo, as the proper leaves clasp the stem in the mature maize-plant. The coty- ledon of maize does not, however, perform the functions of a leaf; on the contrary, it remains in the soil during the act of sprout- ing, and its contents, like those of the endosperm, are absorbed by the plumule and radicle. The leaves which appear above-ground, in the case of maize and the other grains (buckwheat excepted,) are those which in the embryo were wrapped together in the plumule, where they can be plainly distinguished by the aid of a magnifier. It will be noticed that the true grains (which have sheathing leaves and hollow jointed stems) ‘are monocot- yledonous (one-cotyledoned) in the seed. As has been mentioned, this is characteristic of plants with Zndogenous or inside-growing stems, (p. 268.) The seeds of the Exogens (outside-growers) (p. 273) are _ dicotyledonous, iL Braid ans, wo. cotyledons. Those of Fig. 63. 304 HOW CROPS GROW. buckwheat, flax, and tobacco, contain an endosperm. The seeds of nearly all other exogenous agricultural plants are destitute of an endosperm, and, exclusive of the coats, consist-entirely of embryo. Such are the seeds of the Le- guminose, viz., the bean, pea, and clover; of the Crucif- ere, viz., turnip, radish, and cabbage; of ordinary fruits, the apple, pear, cherry, plum, and peach; of the gourd family, viz., the pumpkin, melon and cucumber; and finally of many hard-wooded trees, viz., the oak, maple, elm, birch, and beech. ‘We may best observe the structure of the two-cotyle- doned embryo in the garden or kidney-bean. After a bean has been soaked in warm water for several hours, the coats may be easily removed, and the two fleshy cotyledons, e¢, ¢, in fig. 64, are found divided from each other save at the point where the radicle, «, is seen projecting like a blunt spur. On carefully breaking away one of the cotyledons, we get a side view of the radicle, a, and plumule,d, the former of which was partially and the latter entirely imbedded between the cotyledons. The plumule plainly Fig. 64. exhibits two delicate leaves, on which the unaided eye may note the veins. These leaves are folded together along their mid-ribs, and may be opened and spread out with help of a needle. When the kidney-bean (Phaseolus) germinates, the cot- yledons are carried up into the air, where they become green and constitute the first pair of leaves of the new plant. The second pair are the tiny leaves of the plumule | just described, between which is the bud, whence all the subsequent aerial organs develope in succession. In the horse-bean, (wba), as in the pea, the cotyledons never assume the office of leaves, but remain in the soil and gradually yield a large share of their contents to the Digitized by Microsoft® > REPRODUCTIVE ORGANS OF PLANTS. 3805 growing plant, shriveling and shrinking greatly in bulk, and finally falling away and passing into decay. ae VITALITY OF SEEDS AND THEIR INFLUENCE ON THE PLANTS THEY PRODUCE. Duration of Vitality.—In the mature seed when kept from excess of moisture, the embryo lies dormant. The duration of its vitality is very various. The seeds of the willow, it is asserted, will not grow after having once be- come dry, but must be sown when fresh; they lose their germinative power in two weeks after ripening. With regard to the duration of the vitality of the seeds of agricultural plants there is no little conflict of opinion among those who have experimented with them. The leguminous seeds appear to remain capable of germination during long periods. Girardin sprouted beans that were over a century old. It is said that Grimstone with great pains raised peas from a seed taken froma sealed vase found in the sarcophagus of an Egyptian mum- my, presented to the British Museum by Sir G. Wilkinson, and estimated to be near 3,000 years old. The seeds of wheat usually lose their power of growth after having been kept 3-7 years. Count Sternberg and others are said to have succeeded in germinating wheat taken from an Egyptian mummy, but only after soaking it in o72. Sternberg relates that this ancient wheat mani- fested no vitality when placed in the soil under ordinary circumstances, nor even when submitted to the action of acids or other substances which gardeners sometimes em- ploy to promote sprouting. Vilmorin, from his own trials, doubts altogether the authenticity of the “mummy wheat.” Dietrich, (Hof. Jahr., 1862-3, p. 77,) experimented with seeds of wheat, rye, and a species of Bromus, which Digitized by Microsoft® 306 HOW CROPS GROW. were 185 years old. Nearly every means reputed to favor germination was employed, but without success, After proper exposure to moisture, the place of the germ was usually found to be occupied by a slimy, putrefying liquid. The fact appears to be that the circumstances under which the seed is kept greatly influence the duration of its vitality. If seeds, when first gathered, be thoroughly dried, and then sealed up in tight vessels, or otherwise kept out of contact of the air, there is no reason why their vitality should not endure for ages. Oxygen and moisture, not to mention insects, are the agencies that usually put a speedy limit to the duration of the germina- tive power of seeds. In agriculture it is a general rule that the newer the seed the better the results of its use. Experiments have proved that the older the seed the more numerous the failures to germinate, and the weaker the plants it pro- duces. Londet made trials in 1856-7 with seed-wheat of the years 1856, 755, ’54, and 753. The following table exhibits the results, which illustrate the statement just made. Per cent of seeds Length of leaves four days mM pegtil pe sprouted. after coming up. hundred seeds. Sced of 1853, none — 1854, 51 0.4 to 0.8 inches 269 MS UBSS, 73 Lo 365 Tao, U4 Loe 404 The results of similar experiments made by Haberlandt on various grains, are contained in the following table: Per cent of seeds that germinated in 1861 from the years + 1850 OL 54 55 7 58 59 60 Wheat, 0 0 8 4 %3 60 84 96 Rye, 0 0 0 0 0 0 48 100 Barley, 0 0 24 0 48 33 92 89 Oats, 60 0 56 48 ye 82 80 96 Maize, 0 nottried. 76 56 not tried. 77 100 97 Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS. 307 Results of the Use of long-kept Seeds.—The fact that old seeds yield weak plants is taken advantage of by the florist in producing new varieties. It is said that while the one- year-old seeds of Ten-weeks Stocks yield single flowers, those which have been kept four years give mostly double flowers. In case of melons, the experience of gardeners goes to show that seeds which have been kept several, even seven years, though less certain to come up, yield plants that give the greatest returns of fruit; while plantings of new seeds run excessively to vines. Unripe Seeds,—Experiments by Lucanus prove that seeds gathered while still unripe,—when the kernel is soft and milky, or, in case of cereals, even before starch has formed, and when the juice of the kernel is like water in appearance,—are nevertheless capable of germination, espe- cially if they be allowed to dry in connection with the stem (after-ripening.) Such immature seeds, however, have less vigorous germinative power than those which are allowed to mature perfectly; when sown, many of them fail to come up, and those which do, yield comparatively weak plants at first and in poor soil give a poorer harvest than well-ripened seed. In rich soil, however, the plants which do appear from unripe seed, may, in time, become as vig- orous as any. (Lucanus, Vs. S¢., IV, p. 253.) According to Siegert, the sowing of unripe peas tends to produce earlier varieties. Liebig says: “The gardener is aware that the flat and shining seeds in the pod of the Stock Gillyflower will give tall plants with single flowers, while the shriveled seeds will furnish low plants with double flowers throughout.” Dwarfed or Light Seeds.—Dr. Miller, as well as Hell- riegel, found that light grain sprouts quicker but yields weaker plants, and is not so sure of germinating as heavy grain. Digitized by Microsoft® 308 HOW CROPS GROW. Baron Liebig asserts (Watural Laws of Husbandry, Am, Ed., 1863, p. 24) that “the strength and number of the roots and leaves formed in the process of germination, are, (as regards the non-nitrogenous constituents,) in di- rect proportion to the amount of starch in the seed.” Further, “poor and sickly seeds will produce stunted plants, which will again yield seeds bearing ina great measure the same character.” On the contrary, he states (on page 61 of the same book, foot note,) that “ Boussing- ault has observed that even seeds weighing two or three milligrames, (1-30th or 1-20th of a grain,) sown in an ab- solutely sterile soil, will produce plants in which all the organs are developed, but their weight, after mouths, does not amount to much more than that of the original seed. The plants are reduced in all dimensions; they may, how- ever, grow, flower, and even bear seed, which only requires a fertile soil to produce again a plant of the natural size.” These seeds must be diminutive, yet placed in a fertile soil they give a plant of normal dimensions. We must thence conclude that the amount of starch, gluten, etc.—in other words the weight of a seed—is not altogether an index of the vigor of the plant that may spring from it. Schubert, whose observations on the roots of agricul- tural plants are detailed in a former chapter (p. 242,) says, as the result of much investigation—“ the vigorous devel- opment of plants depends far less upon the size and weight of the seed than upon the depth to which it is cov- ered with earth, and upon the stores of nourishment which it finds in its first period of life.” Value of seed as related to its Density,—From a series of experiments made at the Royal Ag. College at Ciren- cester, in 1863-4, Prof. Church concludes that the value of seed-wheat stands in a certain connection with its spe- cific gravity, (Practice with Science, p. 107, London, 1865.) He found :— Digitized by Microsoft® REPRODUCTIVE ORGANS OF PLANTS, 309 1. That seed-wheat of the greatest density produces the densest seed. 2. The seed-wheat of the greatest density yields the greatest amount of dressed corn. 3. The seed-wheat of medium density generally gives _ the largest number of ears, but the ears are poorer than those of the densest seed. 4, The seed-wheat of medinm density generally pro- duces the largest number of fruiting plants. - 5. The seed-wheats which sink in water but float ina liquid having the specifie gravity 1.247, are of very low value, yielding, on an average, but 34.4 Ibs. of dressed grain for every 100 yielded by the densest seed. The densest grains are not, according to Church, always the largest. The seeds he experimented with ranged from sp. gr. 1.354 to 1.401. Digitized by Microsoft® DIVISION JIL LIFE OF THE PLANT. CHAPTER I. GERMINATION. ae INTRODUCTORY. Having traced the composition of vegetation from its ultimate elements to the proximate organic compounds, and studied its structure in the simple cell as well as in the most highly developed plant, and, as far as needful, explain- ed the characters and functions of its various organs, we approach the subject of VrecrrasLe Lire and Nutrition, and are ready to inquire how the plant increases in bulk and weight and produces starch, sugar, oil, albuminoids, ete., which constitute directly or indirectly almost the entire food of animals. ; The beginning of the individual plant is in the seed, at the moment of fertilization by the action of a pollen tube on the contents of the embryo-sack. Each embryo whose development is thus ensured, is a plant in miniature, or rather an organism that is capable, under proper cireum- stances, of unfolding into a plant. 310 Digitized by Microsoft® GERMINATION. 311 The first process of development, wherein the young plant commences to manifest its separate life, and in which it is shaped into its proper and peculiar form, is called germination. The GENERAL Process and Conpitions of GERMINATION are familiar to'all. In agriculture and ordinary garden- ing we bury the ripe and sound seed a little way in the soil, and in a few days, it usually sprouts, provided it finds a certain degree of warmth and moisture. Let us attend somewhat in detail first to the phenomena of germination and afterward to the requirements of the awakening seed. § 2. . THE PHENOMENA OF GERMINATION. The student will do well to watch with care the various stages of the act of germination, as exhibited in several species of plants. or this purpose a dozen or more seeds of each plant are sown, the smaller, one-half, the larger, one inch deep, in a box of earth or saw-dust, kept duly warm and moist, and one or two of each kind are uncovered and dissected at successive intervals of 12 hours until. the process is complete. In this way it is easy to trace all the visible changes which occur as the embryo is quickened. The seeds of the kidney-bean, pea, of maize, buckwheat, and barley, may be employed. We thus observe that the seed first absorbs a large amount of moisture, in consequence of which it swells and becomes more soft. We see the germ enlarging beneath the seed coats, shortly the integuments burst and the radi- cle appears, afterward the plumule becomes manifest. In all agricultural plants the radicle buries itself in the soil, The plumule ascends into the atmosphere and seeks exposure to the direct light of the sun. Digitized by Microsoft® 312 HOW CROPS GROW. The endosperm, if the seed have one, and in many cases the cotyledons (so with the horse-bean, pea, maize, and barley), remain in the place where the seed was deposited. In other cases (kidney-bean, buckwheat, squash, radish, ete.,) the cotyledons ascend and become the first pair of leaves. The ascending plumule shortly unfolds new leaves, and if coming from the seed of a branched plant, lateral buds make their appearance. The radicle divides and subdi- vides in beginning the issue of true roots. When the plantlet ceases to derive nourishment from the mother seed, the process is finished. § 3, THE CONDITIONS OF GERMINATION. As to the Conditions of Germination we have to con- sider in detail the following :— a. Temperature.—A certain range of warmth is essen- tial to the sprouting of a seed.—Gippert, who experiment- ed with numerous seeds, observed none to germinate be- low 39°. Sachs has ascertained for various agricultural seeds the extreme limits of warmth at which germination is possi- ble. The lowest temperatures range from 41° to 55°, the highest, from 102° to 116°. Below the minimum temper- ature a seed preserves its vitality, above the maximum it is killed. He finds, likewise, that the point at which the most rapid germination occurs is intermediate between these two extremes, and lies between 79° and 93°. Either elevation or reduction of temperature from these degrees retards the act of sprouting. In the following table are given the special tempera- tures for six common plants. Digitized by Microsoft® GERMINATION, 313 Lowest Highest - Temperature of most Temperature. + Temperature. rapid Germination. Wheat, 41° F, 104° F. 84° FF. Barley, 41. 104, 84. Pea, 44.5 102. 84. Maize, 48. 115. 93. Scarlet-bean, 49. 111. 79. Squash, 54, 115. 93. For all agricultural plants cultivated in New England, a range of temperature of from 55° to 90° is adapted for healthy and speedy germination. It will be noticed in the above Table that the seeds of plants introduced into northern latitudes from tropical re- gions, as the squash, bean, and maize, require and endure higher temperatures than those native to temperate lati- tudes, like wheat and barley. The extremes given above are by no means so wide as would be found were we to experiment with other plants. It is probable that some seeds will germinate nearly at 32°, or the freezing point of water, while the cocoa-nut is said to yield seed- lings with greatest certainty when the heat of the soil is 120°. Sachs has observed that the temperature at which germination takes place materially influences the relative development of the parts, and thus the form of the seed- ling. According to this industrious experimenter, very low temperatures retard the production of new rootlets, buds, and leaves. The rootlets which are rudimentary in the embryo become, however, very long. On the other hand, very high temperatures cause the rapid formation of new roots and leaves, even before those existing in the germ are fully unfolded. The medium and most favora- ble temperatures bring the parts of the embryo first into development, at the same time the rudiments of new or- gans are formed which are afterward to unfold. db. Moisture.—A certain amount: of moisture is indis- pensable to all growth. In germination it is needful that : 14 Digitized by Microsoft® 814 HOW CROPS GROW. the seed should absorb water so that motion of the con- tents of the germ-cells can take place. Until the seed is more or less imbued with moisture, no signs of sprouting are manifested, and if a halfsprouted seed be allowed to dry the process of growth is effectually checked. The degree of moisture different seeds will endure or require is exceedingly various. The seeds of aquatic plants naturally germinate when immersed in water. The seeds of many land-plants, indeed, will quicken under wa- ter, but they germinate most healthfully when moist but not wet. Excess of water often causes the seed to rot. e Oxygen Gas.—Liree Oxygen, as contained in the air, is likewise essential. Saussure demonstrated by experi- ment that proper germination is impossible in its absence, and cannot proceed in an atmosphere of other gases. As we shall presently see, the chemical activity of oxygen appears to be the means of exciting the growth of the embryo. d. Light.—It has been taught that light is prejudicial to germination, and that therefore seed must be covered. (Johnston's Lectures on Ag. Chem. & Geology, 2d Eng. Ed, pp. 226 & 227). When, however, we consider that nature does not bury seeds but scatters them on the sur- face of the ground of forest and prairie, where they are, at the most, halfcovered and by no means removed from the light, we cannot accept such a doctrine. The warm and moist forests of tropical regions, which, though shaded, are by no means dark, are covered with sprouting seeds. The gardener knows that the seeds of heaths, calceolarias, and some other ornamental plants, germinate best when uncovered, and the seeds of common agricultural plants will sprout when placed on moist sand or saw-dust, with apparently no less readiness than when buried out of sight. Finally, R. Hoffnann (Jahresbericht wiber Agricultur Chem., 1864, p. 110) has found in experiments with 24 - Digitized by Microsoft® GERMINATION, 315 kinds of agricultural seeds that light exercises no appreci- able influence of any kind on germination. The Time required for Germination varies exceedingly according to the kind of seed. As ordinarily observed, the fresh seeds of the willow begin to sprout within 12 hours after falling to the ground. Those of clover, wheat, and other grains, germinate in three to five days. The fruits of the walnut, pine, and larch, lie four to six weeks before sprouting, while those of some species of ash, beech, and maple, are said not to germinate before the expiration of 14 or 2 years. The starchy and thin-skinned seeds quicken most readi- ly. The oily seeds are in general more slow, while such as are situated within thick and horny envelopes require the longest periods to excite growth. The time necessary for germination depends naturally upon the favorableness of other conditions. Cold and ~ drought delay the process, when they do not check it al- together. Seeds that are buried deeply in the soil may re- main for years, preserving, but not manifesting, their vital- ity, because they are either too dry, too cold, or have not sufficient access to oxygen to set the germ in motion. To speak with precision, we should distinguish the time from planting the dry seed to the commencement of germ- ination which is marked by the rootlet becoming visible, and the period that elapses until the process is complete, i.e., until the stores of the mother-seed are exhausted, and the young plant is wholly cast upon its own resources. At 41° F. in the experiments of Haberlandt, the rootlet issued after 4 days, in the case of rye, and in 5-7 days in that of the other grains and clover. The sugar-beet, how- ever, lay at this temperature 22 days before beginning to sprout. At 51°, the time was shortened about one-half in case of the seeds just mentioned. Maize required 11, kidney- beans 8, and tobacco 81 days at this temperature. Digitized by Microsoft® © : 316 HOW CROPS GROW. _ At 65° the grains, clover, peas, and flax, began to sprout in one to two days; maize, beans, and sugar-beet, in 3 days, and tobacco in 6 days. The time of completion varies with the temperature much more than that of beginning. It is, for example, ac- cording to Sachs, at 41- 55° for wheat and barley 40-45 days, ae 95-100° ce “ce “ce ae 10-12 “cr At a given temperature small seeds complete germina- tion much sooner than large ones. Thus at 55-60° the process is finished with beans in 30-40 days, With maize in 30-35 days. wheat “20-25 clover “ 8-10 “ These differences are simply due to the fact that the smaller seeds have smaller stores of nutriment for the young plant, and are therefore more quickly exhausted. | Proper Depth of Sowing.—The soil ig usually the me- dium of moisture, warmth, etc., to the seed, and it affects germination only as it influences the supply of these agencies; it is not otherwise essential to the process. The burying of seeds, when sown in the field or garden, serves to cover them away from birds and keep them from drying up. In the forest, at spring-time, we may see innumerable seeds sprouting upon the surface, or but half covered with decayed leaves. ; While it is the nearly universal result of experience in temperate regions that agricultural seeds germinate most surely when sown at a depth not exceeding 1-3 inches, there are circumstances under which a widely different practice is admissible or even essential. In the light and porous soil of the gardens of New Haven, peas may be sown 6 to 8 inches deep without detriment, and are thereby better secured from the ravages of the domestic pigeon, The Moqui Indians, dwelling upon the table lands Digitized by Microsoft® GERMINATION. 317 of the higher Colorado, deposit the seeds of maize 12 or 14 inches below the surface. Thus sown, the plant thrives, while, if treated according to the plan usual in the United States and Europe, it might never appear above ground. The reasons for such a procedure are the follow- ing: The country is without rain and almost without dew. In summer the sandy soil is continuously parched by the sun at a temperature often exceeding 100° in the shade. It is only at the depth of a foot or more that the seed finds the moisture needful for its growth,—moisture furnished by the melting of the winter snows.* R. Hoffmann, experimenting in a light, loamy sand, upon 24 kinds of agricultural and market-garden seeds, found that all perished when buried 12 inches. When planted 10 inches deep, peas, vetches, beans, and maize, alone came up; at 8 inches there appeared, besides the above, wheat, millet, oats, barley, and colza; at 6 inches those already mentioned, together with winter colza, buckwheat, and sugar-beets; at 4 inches of depth the above, and mustard, red and white clover, flax, horseradish, hemp, and turnips; finally, at 3 inches, lucern also appeared. Hoffmann states that the deep-planted seeds generally sprouted most quickly, and all early differences in development disap- peared before the plants blossomed. On the other hand, Grouven, in trials with sugar-beet seed, made, most probably, in a well-manured and rather heavy soil, found that sowing at a depth of 3 to 1} inches, gave the earliest and strongest plants; seeds deposited at a depth of 24 inches required 5 days longer to come up than those planted at 2 in. It was further shown that seeds sown shallow in a fine wet clay required 4-5 days longer to come up than those placed at the same depth in the ordinary soil. Not only the character of the soil, which influences the * For these interesting facts the writer is indebted to Prof. J. 8. Newberry. Digitized by Microsoft® 318 HOW CROPS GROW. supply of air, and warmth; but the kind of weather, which determines both temperature and degree of moist- ure, have their effect upon the time of germination, and since these conditions are so variable, the rules of practice are laid down, and must be received with, a certain latitude. § 4, : THE CHEMICAL PHYSIOLOGY OF GERMINATION. Tue Nortririon or tHe Serprine.—The young plant grows at first exclusively at the expense of the seed. It may be aptly compared to the suckling animal, which, when new-born, is incapable of providing its own nourish- ment, but depends upon the milk of its mother. The Nutrition of the Seedling falls into three processes, which, though distinct in character, proceed simultancous- ly. These are, 1, Solution of the Nutritive Matters of the Cotyledons or Endosperm ; 2, Transfer ; and 3, As- similation of the same. 1. The Act of Solution has no difficulty in case of dex- trin, gum, the sugars, albumin, and casein. The water which the seed imbibes to the extent of one-fourth to five-fourths of its weight, at once dissolves them. It is otherwise with the fats or oils, with starch and with gluten, which, as such, are nearly or altogether insol- uble in water. In the act of germination provision is made for transforming these bodies into the soluble ones above mentioned. So far as these changes have been traced, they are as follows: Solution of Fats.—Sachs has recently found that squash- seeds, which, when ripe, contain no starch, sugar, or dex- trin, but are very rich in oil (50°|,,) and albuminoids Digitized by Microsoft® GERMINATION. 319 (40°|,) suffer by germination such chemical change that the oil rapidly diminishes in quantity (nine-tenths disappears,) while at the same time starch, and, in some cases, sugar, is Jormed. (Vs. St., III, p. 1.) Solution of Starch.—The starch that is thus organized from the fat of the oily seeds, or that which exists ready- formed in the farinaceous (floury) seeds, undergoes further changes, which have been previously alluded to (p. 78), whereby it is converted into substances that are soluble in water, viz., dextrin and grape or cane sugar. Solution of Albuminoids.—Finally, the insoluble al- buminoids are gradually transformed into soluble modifi- cations. Chemistry of Malt.—The preparation and properties of malt may serve to give an insight into the nature of the chemical metamorphoses that have just been indicated. The preparation is in this wise. Barley or wheat (sometimes rye) is soaked in water until the kernels are soft to the fingers; then it is drained and thrown up in heaps. The masses of soaked grain shortly dry, become heated, and in a few days the embryos send forth their radicles. The heaps are shoveled over, and spread out so as to avoid too great a rise of temperature, and when the sprouts are about half an inch in length, the germination is checked by drying. The dry mass, after removing the sprouts (radicles,) is malt, such as is used in the manufac- ture of beer. Malt thus consists of starchy seeds whose germination ‘has been checked while in its early stages. The only prod- uct of the beginning growth—the sprouts—being removy- ed, it exhibits in the residual seed the first results of the process of solution. The following figures, derived from the researches of Stein, in Dresden,.( Wilda’s Centralblatt, 1860, 2, pp. 8- 23,) exhibit the composition of 100 parts of Barley, and Digitized by Microsoft® 320 HOW CROPS GROW. of the 92 parts of Malt, and the 23 of Sprouts which 100 parts of barley yield.* ried! ae 24% of Composition of = Barley. Matt. Sprouts, ASH: araleiuansig ndccsteacadeialiat siete 2.42 2.11 0.29 RIP ive be iota eeeee ease 54.48 47.43 Tah avayiiavsihs ata eage atarctowe sarah ola sraterins, 3.56 2.09 0.08 Insoluble Albuminoids.........-. 11.02 9.02 0.87 Soluble SOS errata Selalerstare 1.26 1.96 0.40 DeXtrilcccsaeseaiecae 2460 denies 6.50 6.95 Extractive Matters (soluble in wa- t 0.47 ter and destitute of nitrogen)... 0.90 3.68 Celnlose.tc a. ctiat sade cecenses 19.86 18.76 0.89 100 92 2.5 It is seen from the above statement that starch, fat, and insoluble albuminoids, have diminished in the malting process; while soluble albuminoids, dextrin, and other soluble non-nitrogenous matters, have somewhat increased in quantity. With exception of 3°|, of soluble “extractive matters,” + the diversities in composition between barley and malt are not striking. The properties of the two are, however, remarkably dif ferent. If malt be pulverized and stirred in warm water (155° F.) for an hour or two, the whole of the starch dis- appears, while sugar and dextrin take its place. The former is recognized by the sweet taste of the wort, as the solution is called. On heating the wort to boiling, a quantity of albumin is coagulated, and may be separated by filtering. This comes in part from the transformation of the insoluble albuminoids of the barley. On adding * The analyses refer to the materials in the dry state. Ordinarily they con- tain from 10 to 16 per cent of water. It must not be omitted to mention that the proportions of malt and sprouts, as well as their composition, vary somewhat according to circumstances; and furthermore, the best analyses which it is pos- sible to make are but approximate, + The term extractive matters is here applied to soluble substances, whose precise nature is not understood. They constitute a mixture which the chemist is not able to analyze. Digitized by Microsoft® GERMINATION. 321 to the filtered liquid its own bulk of alcohol, dextrin be- comes evident, being precipitated as a white powder. Furthermore, if we mix 2—3 parts of starch with one of malt, we find that the whole undergoes the same change. An additional quantity of starch remains unaltered. The process of germination thus developes in the seed an agency by which the conversion of starch into soluble carbohydrates is accomplished with great rapidity. Diastase.—Payen & Persoz attribute this action to a nitrogenous substance which they term Diastase, and which is found in the germinating seed in the vicinity of the embryo, but not in the radicles. They assert that one part of diastase is capable of transforming 2,000 parts of starch, first into dextrin and finally into sugar, and that malt yields sjsth of its weight of this substance. A short time previous to the investigations of Payen & Persoz (1833,) Saussure found that Mucidin,* the soluble nitrogenous body which may be extracted from gluten (p. 101,) transforms starch in the manner above described, and it is now known that any albuminoid may produce the same effect, although the rapidity of the action and the amount of effect are usually far less than that exhibit- ed by the so-called diastase. In order, however, that the albuminoids may transform starch as above described, it is doubtless necessary that they themselves enter into a state of alteration; they are _ in part decomposed and disappear in the process. These bodies thus altered become ferments. It must not be forgotten, however, that in all cases in which the conversion of starch into dextrin and sugar is accomplished artificially, an elevated temperature is re- quired, whereas in the natural process, as shown in the * Saussure designated this body mucin, but this term being established as the name of the characteristic ingredient of animal mucus, Ritthausen has replaced it by mucidin. 14* | Digitized by Microsoft® 322 HOW CROPS GROW. germinating seed, the change goes on at ordinary or even low temperatures. It is generally taught that oxygen acting on the album- inoids in presence of water and within a certain range of temperature induces the decomposition which confers on them the power in question. The necessity for oxygen in the act of germination has been thus accounted for, as needful to the solution of the starch, ete., of the cotyledons. This may be true at first, but, as we shall presently see, the chief action of oxygen is probably of another kind. How diastase or other similar substances accomplish the change in question is not certainly known. Soluble Starch.—The conversion of starch into sugar and dextrin is thus in a sense explained. This is not, how- ever, the only change of : 38 which starch is susceptible. 7 2a) (C2) In the bean, (Phaseolus ' re multiflorus), Sachs (Sitz- ungsberichte der Wiener 6 Akad., XXXVII, 57) in- forms us that the starch of the cotyledons is dissolved, passes into the seedling, and reappears (in part, at least) as starch, without conver- ; sion into dextrin or sugar, Fig, 65. as these substances do not appear in the cotyledons during any period of germina- tion, except in small quantity near the joining of the seedling. Compare p. 64, Unorganized Starch. The same authority gives the following account of the microscopic changes observed in the starch-grains themselves, as they undergo solution. The starch-grains of the bean have a narrow interior cavity, (as seen in fig. 65, 1.) This at first becomes filled with a liquid. Digitized by Microsoft® GERMINATION. - : 3823 Next, the cavity appears enlarged (2,) its borders assume a corroded appearance (3, 4,) and frequently channels are seen extending to the surface (4, 5, 6.) Finally, the cavity becomes so large, and the channels so extended, that the starch-grain falls to pieces (7, 8.) Solution con- tinues on the fragments until they have completely disap- peared. In this process it is most probable that the starch assumes the liquid form without loss of its proper chemi- cal characters, though it ceases to strike a blue color with iodine.* Soluble Albuminoids.—As we have seen (p. 104,) in- soluble animal fibrin and casein, by long keeping with imperfect access of air, pass into soluble bodies, and lat- terly E. Mulder has shown that diastase rapidly accom- plishes the same change. It would appear, in fact, that the conversion of a small quantity of any albuminoid into a ferment, by oxidation, is sufficient to render the whole soluble. The ferment exerts on the bodies from which it is formed, an action similar to that manifested by it to- wards starch and other carbohydrates. The production of small quantities of acetic and lactic acids (the acids of vinegar and of sour milk) has been observed in germination. These acids perhaps assist in the solution of the albuminoids. Gaseous Products of Germination. — Before leaving this part of our subject, it is proper to notice some other results of germination which have been thought to belong to the process of solution. On referring to the table of the composition of malt, we find that 100 parts of dry barley yield 92 parts of malt and 2} of sprouts, leaving 54 parts unaccounted for. In the malting process 1} parts of the grain are dissolved in the water in which it is soaked. The remaining 4 parts escape into the atmos- phere in the gaseous form. * According to Licbig, this blue reaction depends upon the adhesion of the iodine to the starch, and is not the result of a chemical combination. Digitized by Microsoft® 324 HOW CROPS GROW. Of the elements that assume the gaseous condition, car- bon does so to the greatest extent. It unites with atmos- pheric oxygen (partly with the oxygen of the seed, ac- cording to Oudemans) producing carbonic acid gas (CO,.) Hydrogen is likewise separated, partly in union with oxygen, as water (H,O), but to some degree in the free state. Free nitrogen appears in considerable amount, (Schulz, Jour. fiir Prakt, Chem., 87, p. 163,) while very minute quantities of Hydrogen and of Nitrogen combine to gaseous ammonia (NH,,.) Heat developed in Germination, — These chemical changes, like all processes of oxidation, are accompanied with the production of heat. The elevation of tempera- ture may be imperceptible in the germination of a single seed, but it nevertheless occurs, and is doubtless of much importance in favoring the life of the young plant. The heaps of sprouting grain seen in the malt-house warm so rapidly and to such an extent, that much care is requisite to regulate the process; otherwise the malt is damaged by over-heating. 2. The Transfer of the Nutriment of the Seedling from the cotyledons or endosperm where it has undergone solution, takes place through the medium of the water which the seed absorbs so largely at first. This water fills the cells of the seed, and, dissolving their contents, carries them into the young plant as rapidly as they are required. The path of their transfer lies through the point where the embryo is attached to the cotyledons ; thence they are distributed at first chiefly downwards into the extending radicles, after a little while both down- wards and upwards toward the extremities of the seedling. Sachs has observed that the carbohydrates (sugar and dextrin) occupy the cellular tissue of the rind and pith, which are penetrated by numerous air-passages; while at first the albuminoids chiefly diffuse themselves through Digitized by Microsoft® GERMINATION. 325 the intermediate cambial tissue, which is destitute of air- passages, and are present in largest relative quantity at the extreme ends of the rootlets and of the plumule. In another chapter we shall notice at length the phenom- ena and physical laws which govern the diffusion of liq- uids into cach other and through membranes similar to those which constitute the walls of the cells of plants, and there shall be able to gather some idea of the causes which set up and maintain the transfer of the materials of the seed into the infant plant. 3. Assimilation is the conversion of the transferred nutri- ment into the substance of the plant itself. This process involves two stages, the first being a chemical, the second, a structural transformation, The chemical changes in the aie are, in part, simply the reverse of those which occur in the cotyledons; viz., the soluble and structureless proximate principles are met amorphosed into the insoluble and organized ones of the same chemical composition. Thus, dextrin may pass into cellulose, and the soluble albuminoids may revert in part to the insoluble condition in which they existed in the ripe seed, But many other and more intricate changes proceed in in the act of assimilation. With regard to a few of these we have some imperfect knowledge. Dr. Sachs informs us that when the embryo begins to grow, its expansion at first consists in the enlargement of the ready-formed cells. As a part elongates, the starch which it contains (or which is formed in the early stages of this extension), disappears, and sugar is found in its stead, dissolved in the juices of the cells. When the organ has attained its full size, sugar can no longer he detected ; while the walls of the cells are found to have grown both in circumference and thickness, thus indicating the accumu- lation of cellulose. Digitized by Microsoft® 326 HOW CROPS GROW. Oxygen Gas needful to Assimilation.—Traube has made some experiments, which seem to prove conclusively that the process of assimilation requires free oxygen to surround and to be absorbed by the growing parts of the germ, This observer found that newly-sprouted pea-seedlings continued to develope in a normal manner when the cot- yledons, radicles, and lower part of the stem, were with- drawn from the influence of oxygen by coating with var- nish or oil. On the other hand, when the tip of the ‘plumule, for the length of about an inch, was coated with oil thickened with chalk, or when by any means this part of the plant was withdrawn from contact with free oxygen, the seedling ceased to grow, withered, and shortly perish- ed. Traube observed the elongation of the stem by the following expedient. A young pea-plant was fastened by the cotyledons to a rod, and the stem and rod were both graduated by deli- cate cross-lines, laid on at equal intervals, by means of a brush dipped in a mixture of oil and indigo. The growth of the stem was now manifest by the widening of the spaces between the lines; and by comparison with those on the rod, Traube remarked that no growth took place at a distance of more than 10-12 lines from the base of the terminal bud. Here, then, is a coincidence which appears to demonstrate that free oxygen must have access to a growing part. The fact is further shown by varnishing one side of the stem of a young pea. The varnished side ceases to extend, the uncoated portion continues enlarging, which results in, and is shown by, a curvature of the stem. Traube further indicates in what manner the elabora- tion of cellulose from suzar may require the codperation of oxygen and evolution of carbonic acid, as expressed by the subjoined equation. Glucose. Oxygen. Carbonic Acid. Water. Cellulose. 3 (Cia Hoy Oy2) + 240 = 12 (COz) + 14 (H20) + Cys Hoo Oro. Digitized by Microsoft® FOOD AFTER GERMINATION. 3827 When the act of germination is finished, which occurs as soon as the cotyledons and endosperm are exhausted of all their soluble matters, the plant begins a fully inde- pendent life. Previously, however, to being thus thrown upon its own resources, it has developed all the organs needful to collect its food from without; it has unfolded its perfect leaves into the atmosphere, and pervaded a por- tion of soil with its rootlets, , During the latter stages of germination it gathers its nutriment both from the parent seed and from the exter- nal sources which afterward serve exclusively for its sup- port. Being fully provided with the apparatus of nutrition, its development suffers no check from the exhaustion of the mother seed, unless it has germinated in a sterile soil, or under other conditions adverse to vegetative life. CHAPTER IL g 1, THE FOOD OF THE PLANT WHEN INDEPENDENT OF THE SEED. This subject will be sketched in this place in but the briefest outlines. To present it fully would necessitate entering into a detailed consideration of the Atmosphere and of the Soil whose relations to the Plant, those of the soil especially, are very numerous and complicated. A separate volume is therefore required for the adequate ‘treatment of these topics. The Roots of a plant, which are in intimate contact with the soil, absorb thence the water that fills the active Digitized by Microsoft® 328 HOW CROPS GROW. cells; they also imbibe such salts as the water of the soil holds in solution; they likewise act directly on the soil, and dissolve substances, which are thus first made of avail to them. The compounds that the plant must derive from the soil are those which are found in its ash, since these are not volatile, and cannot, therefore, exist in the atmos- phere. The root, however, commonly takes up some other elements of its nutrition to which it has immediate access. Leaving out of view, for the present, those matters which, though found in the plant, appear to be unessential to its growth, viz., silica, soda and manganese, the roots absorb the following substances, viz. : Sulphates ] Potash. Phosphates Lime. Nitrates and oF 1 Magnesia and Chlorides { Tron. These salts enter the plant by the absorbent surfaces of the younger rootlets, and pass upwards through the active portions of the stem, to the leaves and to the new-forming buds. The Leaves, which are unfolded to the air, gather from it Carbonic Acid Gas. This compound suffers decompo- sition in the plant; its Carbon remains there, its Oxygen or an equivalent quantity, very nearly, is thrown off into the air again. The decomposition of carbonic acid takes place only by day and under the influence of the sun’s light. From the carbon thus acquired and the elements of wa- ter with the codperation of the ash-ingredients, the plant organizes the Carbohydrates. Probably glucose, perhaps dextrin or soluble starch, are the first products of this synthesis. The formation of carbohydrates appears to proceed in the chlorophyll-cells of the leaf. The Albuminoids require for their production the pres- ence of a compound of Mitrogen. The salts of Witrie Digitized by Microsoft® "e FOOD AFTER GERMINATION, 329 Acid (nitrates) are commonly the chief, and may be the only supply of this element. The other proximate principles, viz. pectose, the fats, the alkaloids, and the acids, are built up from the same food-elements. In all cases the steps in the construc- tion of organic matters are unknown to us, or subjects of uncertain conjecture. The carbohydrates, albuminoids, ete., that are organized in the foliage, are not only transformed into the solid tis- sues of the leaf, but descend and diffuse to every active organ of the plant. The plant has within certain limits a power of selecting its food. The sea-weed, as has been remarked, contains more potash than soda, although the latter is 30 times more abundant than the former in the water of the ocean. Vegetation cannot, however, entirely shut out either ex- cess of nutritive matters or bodies that are of no use or even poisonous to it. The functions of the Atmosphere are essentially the same towards plants, whether growing under the condi- tions of aqueculture, or under those of agriculture. The Soil, on the other hand, has offices which are peculiar to itself. We have seen that the roots of a plant have the power to decompose salts, e. g. nitrate of potash and chloride of ammonium (p. 170,) in order to appropriate one of their ingredients, the other being rejected. In aqueeculture, the experimenter must have a care to re- move the substance which would thus accumulate to the detriment of the plant. In agriculture, the soil, by virtue of its chemical and physical qualities, renders such reject- ed matters comparatively insoluble, and therefore innoc- uous. The Atmosphere is nearly invariable in its composition at all times and over all parts of the earth’s surface. Its power of directly feeding crops has, therefore,.a natural limit, which cannot be increased by art. Digitized by Microsoft® 330 HOW CROPS GROW. The Soil, on the other hand, is very variable in compo- sition and quality, and may be enriched and improved, or deteriorated and exhausted. From the Atmosphere the crop can derive no appreci- able quantity of those elements that are found in its Ash. In the Soil, however, from the waste of both plants and animals, may accumulate large supplies of all the elements of the Volatile part of Plants. Carbon, certainly in the form of carbonic acid, probably or possibly in the condi- tion of Humus (Vegetable Mould, Muck), may thus be put, as food, at the disposition of the plant. Nitrogen is chiefly furnished to crops by the soil. Nitrates are formed in the latter from various sources, and ammonia-salts, to- gether with certain proximate animal principles, viz., urea, guanin, tyrosin, uric acid and hippuric acid, likewise serve to supply nitrogen to vegetation and are ingredients of the best manures. It is, too, from the soil that the crop gathers all the Water it requires, which not only serves as the fluid medium of its chemical and structural metamorphoses, but likewise must be regarded as the ma- terial from which it mostly appropriates the Hydrogen and Oxygen of its solid components. 8 2. THE JUICES OF THE PLANT, THEIR NATURE AND MOVEMENTS. Very erroneous notions are entertained with regard to the nature and motion of sap. It is commonly taught that there are two regular and opposite currents of sap circu- lating in the plant. It is stated that the “crude sap” is taken up from the soil by the roots, ascends through the Digitized by Microsoft® MOTION OF THE JUICES. 331 vessels (ducts) of the wood, to the leaves, there is concen- trated by evaporation, “elaborated” by the processes that go on in the foliage, and thence descends through the vessels of the inner bark, nourishing these tissues in its way down. The facts from which this theory of the sap first arose, all admit of a very different interpretation: while numerous considerations demonstrate the essential falsity of the theory itself. Flow of sap in the plant—not constant or necessary. —We speak of the Flow of Sap as if a rapid current were incessantly streaming through the plant, as the blood circulates in the arteries and veins of an animal, This is an erroneous conception. A maple in early March, without foliage, with its whole stem enveloped in a nearly impervious bark, its buds wrapped up in horny scales, and its roots surrounded by cold or frozen soil, cannot be supposed to have its sap in motion. Its juices must be nearly or absolutely at rest, and when sap runs copiously from an orifice made in the trunk, it. is simply because the tissues are charged with water under pressure, which escapes at any outlet that may be opened for it. The sap is at rest until motion is caused by a perforation of the bark and new wood. So, too, when a plant in early leaf is situated in an atmosphere charged with moisture, as happens on a rainy day, there is little motion of its sap, although, if wounded, motion will be established, and water will stream more or less from all parts of the plant towards the cut. Sap does move in the plant when evaporation of water goes on from the surface of the foliage. This always hap- pens whenever the air is not saturated with vapor. When a wet cloth hung out, dries rapidly by giving up its moisture to the air, then the leaves of plants lose their water more or less readily, according to the nature of the foliage. Mr. Lawes found that in the moist climate of England Digitized by Microsoft® 332 HOW CROPS GROW. common plants (Wheat, Barley, Beans, Peas, and Clover), exhaled during 5 months of growth, more than 200 times their (dry) weight of water. The water that thus evap- orates from the leaves is supplied by the soil, and en- tering the roots, rapidly streams upwards through the stem as long as a waste is to be supplied, but ceases when evaporation from the foliage is checked. The upward motion of sap is therefore to a great de- gree independent of the vital processes, and comparatively unessential to the welfare of the plant. Flow of sap from the plant. “ Bleeding.”’—It is a familiar fact, that from a maple tree “tapped” in spring- time, or from a grape-vine wounded at the same season, a copious flow of sap takes place, which continues for a num- ber of weeks. The escape of liquid from the vine is com- monly termed “bleeding,” and while this rapid issue of sap is thus strikingly exhibited in comparatively few cases, bleeding appears to be a universal phenomenon, one that may occur, at least, to some degree, under certain con- ditions with every plant. The conditions under which sap flows are various, ac- cording to the character of the plant. Our perennial trees have their annual period of active growth in the warm season, and their vegetative functions are nearly suppressed during cold weather. As spring approaches the tree renews its growth, and the first evidence of change within is furnished by its bleeding when an opening is made through the bark into the young wood. A maple, tapped for making sugar, loses nothing until the spring warmth attains a certain intensity, and then sap begins to flow from the wounds in its trunk. The flow is not con- stant, but fluctuates with the thermometer, being more copious when the weather is warm, and falling off or suf fering check altogether as it is colder. The stem of the living maple is always charged with Digitized by Microsoft® MOTION OF THE JUICES. 333 water, and never more so than in winter.* This water is either pumped into the plant, so to speak, by the root- power already noticed (p. 248,) or it is generated in the trunk itself. The water contained in the stem in cold weather is undoubtedly that raised from the soil in the autumn. That which first flows from an augur-hole, in March, may be simply what was thus stored in the trunk; but, as the escape of sap goes on for 14 to 20 days at the rate of several gallons per day from a single tree, new quantities of water must be continually supplied. That these are pumped in from the root is, at first thought, dif ficult to understand, because as we have seen (p. 250) the root-power is suspended by a certain low temperature (unknown in case of the maple) and the flow of sap often begins when the ground is covered with one or two feet of snow, and when we cannot suppose the soil to have a higher temperature than it had during the previous win- ter months. Nevertheless, it must be that the deeper roots are warm enough to be active all the winter through, and that they begin their action as soon as the trunk ac- quires a temperature sufficiently high to admit the move- ment of water in it. That water may be produced in the trunk itself to a slight extent is by no means impossible, for chemical changes go on ‘there in spring-time with much rapidity, whereby the sugar of the sap is formed. These changes have not been sufficiently investigated, however, to prove or disprove the generation of water, and we must, in any case, assume that it is the root-power which chiefly maintains a pressure of liquid in the tree. The issue of sap from the maple tree in the sugar-season * Experiments made in Tharand, Saxony, under direction of Stoeckhardt, show that the proportion of water, both in the bark and wood of trees, varies considerably in different seasons of the year, ranging, in case of the beech, from 35 to 49 percent of the fresh-felled tree. The greatest proportion of water in the wood was found in the months of December and January; in the bark, in March to May. The minimum of water in the wood occurred in May, June, and July; in the bark, much irregularity was observed. Chem. Ackersmann, 1866, p. 159. Digitized by Microsoft® 334 HOW CROPS GROW. is closely connected with the changes of temperature that take place above ground. The sap begins to flow from a cut when the trunk itself is warmed to a certain point, and, in general, the flow appears to be the more rapid the warmer the trunk. During warm, clear days, the radiant heat of the sun is absorbed by the dark, rough surface of the tree most abundantly; then the temperature of the latter rises most speedily and acquires the greatest eleva- tion—even surpasses that of the atmosphere by several degrees; then, too, the yield of sap is most copious. On clear nights, cooling of the tree takes place with corre- sponding rapidity ; then the snow or surface of the ground is frozen, and the flow of sap is checked altogether. From trees that have a sunny exposure, sap runs earlier and faster than from those having a cold northern aspect. Sap starts sooner from the spiles on the south side of a tree than from those towards the north. Duchartre, (Comptes Rendus, LX, 754,) passed a vine situated in a grapery, out of doors, and back again, through holes, so that a middle portion of the stem was exposed to a steady winter temperature ranging from 18 to 10° F., while the remainder of the vine, in the house, was surrounded by an atmosphere of 70° F. Under these circumstances the buds Within developed vigorously, but those without remained dormant and opened not a day sooner than buds upon an adjacent vine whose stem was all out of doors. That sap passed through the cold part of the stem was shown by the fact that the interior shoots sometimes wilted, but again recovered their turgor, which could only happen from the partial suppression and renewal of a supply of water through the stem. Payen examined the wood of the vine at the conclusion of the experiment, and found the starch which it originally con- tained to have been equally removed from the warm and the exposed parts. That the rate at which sap passed through the stem was Digitized by Microsoft® MOTION OF THE JUICES. 335 influenced by its temperature is a plain deduction from the fact that the leaves within were found wilted in the morning, while they recovered toward noon, although the temperature of the air without remained below freezing. The wilting was no doubt chiefly due to the diminished power of the stem to transmit water; the return of the leaves to their normal condition was probably the conse- quence of the warming of the stem by the sun’s radiant heat.* One mode in which changes of temperature in the trunk influence the flow of sap is very obvious. The wood-cells contain, not only water, but air. Both are expanded by heat, and both contract by cold. Air, especially, under- goes a decided change of bulk in this way. Water ex- pands nearly one-twentieth in being warmed from 32° to 212°, and air increases in volume more than one-third by the same change of temperature. When, therefore, the trunk of a tree is warmed by the sun’s heat the air is ex- panded, exerts a pressure on the sap, and forces it out of any wound made through the bark and wood-cells. It only requires a rise of temperature to the extent of a few degrees to occasion from this cause alone a considerable flow of sap from a large tree. (Hartig.) If we admit that water continuously enters the deep-ly- ing roots whose temperature and absorbent power must remain, for the most part, invariable from day to day, we should have a constant slow escape of sap from the trunk were the temperature of the latter uniform and sufticiently high. This really happens at times during every sugar- season. When the trunk is cooled down to the freezing point, or near it, the contraction of air and water in the tree makes a vacuum there, sap ceases to flow, and air is * The temperature of the aér is not always a sure indication of that of the solid bodies which it surrounds. A thermometer will often rise by exposure of the bulb to the direct zays of the sun, 30 or 40° above its indications when in the shade, Digitized by Microsoft® 336 HOW CROPS GROW. sucked in through the spile; as the trunk becomes heated again, the gaseous and liquid contents of the ducts ex- pand, the flow of sap is renewed, and proceeds with in- creased rapidity until the internal pressure passes its max- imum. As the season advances and the soil becomes heated, the root-power undoubtedly acts with increased vigor and larger quantities of water are forced into the trunk, but at a certain time the escape of sap from a wound suddenly ceases. At this period a new phenomenon supervenes. The buds which were formed the previous summer begin to expand as the vessels are distended with sap, and final- ly, when the temperature attains the proper range, they unfold into leaves. At this point we have a proper mo- tion of sap in the tree, whereas before there was little mo- tion at all in the sound trunk, and in the tapped stem the motion was towards the orifice and thence out of the tree. The cessation of flow from a cut results from two cir- cumstances: first, the vigorous cambial growth, whereby incisions in the bark and wood rapidly heal up; and sec- ond, the extensive evaporation that goes on from foliage. That evaporation of water from the leaves often pro- ceeds more rapidly than it can be supplied by the roots is shown by the facts that the delicate leaves of many plants wilt when the soil about their roots becomes dry, that water is often rapidly sucked into wounds on the stems of trees which are covered, with foliage, and that the proportion of water in the wood of the trees of tem- perate latitudes is least in the months of May, June, and July. Evergreens do not bleed in the spring-time. The oak loses little or no sap, and among other trees great diversity is noticed as to the amount of water that escapes at a wound on the stem. In case of evergreens we have a stem destitute of all proper vascular tissue, and admitting a flow of liquid only through the perforations of the wood- Digitized by Microsoft® COMPOSITION OF THE JUICES. 338% cells, which, from their content of resinous matters, should imbibe water less readily than other kinds of wood. Again, the leaves admit of continual evaporation, and fur- nish an outlet to the water. The colored heart-wood ex- isting in many trees is impervious to water, as shown by the experiments of Boucherie and Hartig. Sap can only flow through the white, so-called sap-wood. In early June, the new shoots of the vine do not bleed when cut, nor does sap flow from the wounds made by breaking them off close to the older stem, although a gash in the latter bleeds profusely. In the young branches, there are no _ channels that permit the rapid efflux of water. Composition of Sap.—The sap in all cases consists chiefly of water. This liquid, as it is absorbed, brings in from the soil a small proportion of certain saline matters —the phosphates, sulphates, nitrates, etc., of the alkalies and alkali-earths. It finds in the plant itself its organic ingredients. These may be derived from matters stored in reserve during a previous year, as in the spring sap of trees; or may be newly formed, as in summer growth. The sugar of maple-sap, in spring, is undoubtedly pro- duced by the transformation of starch which is found abundantly in the wood in winter. According to Hartig, (Jour. fir Prakt. Ch., 5, p. 217, 1835,) all deciduous trees contain starch in their wood and yield a sweet spring sap, while evergreens contain little or no starch. Hartig re- ports having been able to procure from the root-wood of the horse-chestnut in one instance no less than 26 per cent of starch. This is deposited in the tissues during sum- mer and autumn to be dissolved for the use of the plant in developing new foliage. In evergreens and annual plants the organic matters of the sap are derived more di- rectly from the foliage itself. The leaves absorb carbonic acid and unite its carbon to the elements of water, with the production of sugar and other carbohydrates. In the leaves, also, probably nitrogen from the nitrates and am- 15 Digitized by Microsoft® 338 HOW CROPS GROW. monia-salts gathered by the roots, is united to carbon, hy- drogen, and oxygen, in the formation of albuminoids, Besides sugar, malic acid and minute quantities of al- bumin exist in maple sap. Towards the close of the sugar-season the sap appears to contain other organic sub- stances which render the sugar impure, brown in color, and of different flavor. It is a matter of observation that maple-sugar is whiter, purer, and “grains” or crystallizes more readily in those years when spring-rains or thaws are least frequent. This fact would appear to indicate that the brown organic matters which water extracts from leaf-mould may enter the roots of the trees, as is the belief of practical men. The spring-sap of many other deciduous trees of tem- perate climates contains sugar, but while it is cane sugar in the maple, in other trees it consists mostly or entirely of grape sugar. Sugar is the chief organic ingredient in the juice of the sugar cane, Indian corn, beet, carrot, turnip, and parsnip. The sap that flows from the vine and from many culti- vated herbaceous plants contains little or no sugar; in that of the vine, gum or dextrin is found in its stead. What has already been stated makes evident that we cannot infer the quantity of sap im a plant from what may run out of an incision, for the sap that thus issues is for the most part water forced up from the soil. It is equally plain that the sap, thus collected, has not the normal composition of the juices of the plant; it must be diluted, and must be the more diluted the longer and the more rap- idly it flows. Ulbricht has made partial analyses of the sap obtained from the stumps of potato, tobacco and sun-flower plants. He found that successive portions, collected separately, exhibited a decreasing concentration. In sunflower sap, gathered in five successive portions, the liter contained the following quantities (grams) of solid matter ; Digitized by Microsoft® COMPOSITION OF THE JUICES. 3839 1 2 3 4 5 Volatile substance - 1.45 0.60 0.30 0.25 0.21 Ash - - - - - - 1.58 1.56 1.18 0.70 0.60 Total - - - - 3.03 2.16 148 0.95 0.81 The water which streams from a wound dissolves and carries forward with it matters, that in the uninjured plant would probably suffer a much less rapid and extensive translocation. From the stump of a potato-stalk would issue by the mere mechanical effect of the flow of water substances generated in the leaves whose proper movement in the uninjured plant would be downwards into the tubers. Different kinds of sap.—It is necessary at this point in our discussion to give prominence to the fact that there are different kinds of sap in the plant. As we have seen, (p. 267,) the cross section of the plant presents two kinds of tissue, the cellular and vascular. These carry different juices, as is shown by their chemical reactions. In the cell-tissues exist chiefly the non-nitrogenous principles, sugar, starch, oil, etc. The liquid in these cells, as Sachs has shown, commonly contains also organic acids and acid- salts, and hence gives a blue color to red litmus. In the vascular tissue albuminoids preponderate, and the sap of the ducts commonly has an alkaline reaction towards test papers. These different kinds of sap are not, however, always strictly confined to either tissue. In the root-tips and buds of many plants (maize, squash, onion) the young (uew-formed) cell-tissue is alkaline from the preponderance of albuminoids, while the spring sap flowing from the ducts and wood of the maple is faintly acid. In many plants is found a system of channels (milk- ducts) independent of the vascular bundles, which contain an opaque, white, or yellow juice. This liquid is seen to Digitized by Microsoft® 340 HOW CROPS GROW. exude from the broken stem of the milk-weed (Asclepias,) of lettuce, or of celandine (Chelidonium,) and may be noticed to gather in drops upon a fresh-cut slice of the sweet potato. The milky juice often differs not more strikingly in appearance than it does in taste, from the transparent sap of the cell-tissue and vascular bundles, The former is commonly acrid and bitter, while the latter is sweet or simply insipid to the tongue. Motion of the Nutrient Matters of the plant.—The occasional rapid passage of a current of water upwards through the plant must not be confounded with the normal, necessary, and often contrary motion of the nutrient mat- ters out of which new growth is organized, but is an in- dependent or highly subordinate process by which the plant adapts itself to the constant changes that are taking place in the soil and atmosphere as regards their content of moisture. A plant supplied with enough moisture to keep its tis- sues turgid is in a normal state, no matter whether the water within it is nearly free from upward flow or ascends rapidly to compensate the waste by evaporation. In both cases the motion of the matters dissolved in the sap is nearly the same. In both cases the plant developes nearly alike. In both cases the nutritive matters gathered at the root-tips ascend, and those gathered by the leaves descend, being distributed to every growing cell; and these motions are comparatively independent of, and but little influenced by, the motion of the water in which they are dissolved. The upward flow of sap in the plant is confined to the vascular bundles, whether these are arranged symmetvi- cally and compactly, as in exogenous plants, or distributed singly through the stem, as in the endogens. This is not only seen upon a bleeding stump, but is made evident by the oft-observed fact that colored liquids, when absorbed into a plant or cutting, visibly follow the course of the Digitized by Microsoft® MOVEMENTS OF NUTRIENT MATTERS. 341 vessels, though they do not commonly penetrate the spiral ducts, but ascend in the sieve-cells of the cambium,* The rapid supply of water to the foliage of a plant, either from the roots or from a vessel in which the cut stem is immersed, goes on when the cellular tissues of the bark and pith are removed or interrupted, but is at once checked by severing the vascular bundles. The proper motion of the nutritive matters in the plant —of the salts dissolved from the soil and of the organic principles compounded from carbonic acid, water, and nitric acid or ammonia in the leaves—is one of slow dif- Jusion mostly through the walls of imperforate cells, and goes on in all directions. New growth is the formation and expansion of new cells into which nutritive substances are imbibed, but not poured through visible passages. When closed cells are converted into ducts or visibly com- municate with each other by pores, their expansion has ceased. Henceforth they merely become thickened by in- terior deposition. Movements of Nutrient Matters in the Bark or Rind. —The ancient observation of what ordinarily ensues when a,ring of bark is removed from the stem of an exogenous tree, led to the erroneous assumption of a formal down- ward current of “elaborated” sap in the bark. When a cutting from one of our common trees is girdled at its middle and then placed in circumstances favorable for growth, as in moist, warm air, with its lower extremity in water, roots form chiefly at the edge of the bark just above the removed ring. The twisting, or half-breaking, as well as ringing of a layer, promotes the development of roots. Latent buds are often called forth on the stems of fruit trees, and branches grow more vigorously, by making a transverse incision through the bark just below * As in Unger’s experiment of placing a hyacinth in the juice of the poke- weed (Phytolacca,) or in Hallier’s observations on cuttings dipped in cherry-juice, (Vs. St., TX, p. 1.) . Digitized by Microsoft® 342 HOW CROPS GROW. the point of their issue. Girdling a fruit - bearing branch of the vine near its junction with the older wood has the effect of greatly en- larging the grapes. It is well known that a wide wound made on the stem of a tree heals up by the formation of new wood, and commonly the growth is most rapid and abundant above the cut. From these facts it was con- cluded that sap descends in the bark, and, not being able to pass below a wound, leads to the organization of new roots or wood just above it. ‘The accompanying illustration, fig. 66, represents the+base of a cut- ting from an exogenous stem (pear or currant) girdled at Band kept for some days immersed in water to the depth indicated by the line Z. The first manifestation of growth is the formation of a protuberance at the lower edge of the bark, which is known to gardeners as a callous, C. This is an extension of the cellular tissue. From the callous shortly appear rootlets, 2, which originate from the vascular tissue. Rootlets also break from the stem above the callous and also above the water, if the air be moist. They appear like- wise, though in less number, below the girdled place. Nearly all the organic sub- stances (carbohydrates, al- buminoids, lignin, etc.,) that Digitized by Microsoft® MOVEMENTS OF NUTRIENT MATTERS. 343 are formed in a plant are produced in the leaves, and must necessarily find their way down to nourish the stem and roots. The facts just mentioned demon- strate, indeed, that they do go down in the bark. We have, however, no proof that there is a downward flow of sap. Such a flow is not indicated by a single fact, for, as we have before seen, the only current of water in the uninjured plant is the upward one which results from root-action and evaporation, and that is variable and mainly independent of the distribution of nutritive matters. . Closer investigation has shown that the most abundant downward movement of the nutrient matters generated in the leaves proceeds in the thin-walled sieve-cells of the cambium, which, in exogens, is young tissue common to the outer wood and the inner bark—which, in fact, unites bark and wood. The tissues of the leaves communicate directly with, and are a continuation of, the cambium, and hence matters formed by the leaves must move most rapid- ly in the cambium. If they pass with greatest freedom through the sieve-cells, the fact is simply demonstration that the latter communicate most directly with those parts of the leaf in which the matters they conduct are organized. In endogenous plants and in some exogens (Piper me- dium, Amaranthus sanguineus) the vascular bundles con- taining sieve-cells pass into the pith and are not confined to the exterior of the stem. Girdling such plants does not give the result above described. With them, roots are formed chiefly or entirely at the base of the cutting, (Hanstein,) and not above the girdled place. In all cases, without exception, the matters organized in the leaves, though most readily and abundantly moving downwards in the vascular tissues, are not confined to them exclusively. When a ring of bark is removed from a tree, the new cell-tisswes, as well as the vascular, are in- terrupted. Notwithstanding, matters are transmitted downwards, through the older wood. When but a narrow Digitized by Microsoft® 344 HOW CROPS GROW. ring of bark is removed from a cutting, roots often appear below the incision, though in less number, and the new growth at the edges of a wound on the trunk of a tree, though most copious above, is still decided below—goes on, in fact, all around the gash. Both the cell-tissue and the vascular thus admit of the transport of the nutritive matters downwards. In the former, the carbohydrates—starch, sugar, inulin—the fats, and acids, chiefly occur and move. In the large ducts, air is contained, except when by vigorous root-action the stem is surcharged with water. In the sieve-ducts (cambium) are found the albuminoids, though not unmixed with car- bohydrates. If a tree have a deep gash cut into its stem, (but not reaching to the colored heart-wood,) growth is not suppressed on either side of the cut, but the nutritive matters of all kinds pass out of a vertical direction around the incision, to nourish the new wood above and below. Girdling a tree is not fatal, if done in the spring or early summer when growth is rapid, provided that the young cells, which form externally, are protected from dryness and other destructive influences. An artificial bark, i. e., a covering of cloth or clay to keep the exposed wood moist and away from air, saves the tree until the “wound heals over.* In these cases it is obvious that the substances which commonly preponderate in the sieve- ducts must pass through the cell-tissue in order to reach the point where they nourish the growing organs. Evidence that nutrient matters also pass wpwards in the bark is furnished, not only by tracing the course of ‘colored liquids in the stem, but also by the fact that unde- veloped buds perish in most cases when the stem is gir- dled between them and active leaves. In the exceptions to this rule, the vascular bundles penetrate the pith, and * Tf the freshly exposed wood be rubbed or wiped with a cloth, whereby the moist cambial layer (of cells containing nuclei and capable of multiplying) is re- moved, no growth can occur. Ratzeburg. Digitized by Microsoft® MOVEMENTS OF NUTRIENT MATTERS, 345 thereby demonstrate that they are the channels of this movement. A minority of these exceptions again makes evident that the sieve-cells are the path of transfer, for, as Hanstein has shown, in certain plants (Solanacee, Asclep- iadez, etc.,) sieve-cells penetrate the pith unaccompanied by any other elements of the vascular bundle, and girdled twigs of these plants grow above as well as beneath the wound, although all leaves above the girdled place be cut off, so that the nutriment of the buds must come from be- low the incision. The substances which are organized in the foliage of a plant, as well as those which are imbibed by the roots, move to any point where they can supply a want. Car- ’ ' bohydrates pass from the leaves, not only downwards, to nourish new roots, but upwards, to feed the buds, flowers, and fruit. In case of cereals, the power of the leaves to gather and organize atmospheric food nearly or altogether ceases as they approach maturity. The seed grows at the expense of matters previously stored in the foliage and stems (p. 218,) to such an extent that it may ripen quite perfectly although the plant be cut when the kernel is in the milk, or even earlier, while the juice of the seeds is still watery and before starch-grains have begun to form. In biennial root-crops, the root is the focus of motion for the matters organized by growth during the first year; but in the second year the stores of the root are com- pletely exhausted for the support of flowers and seed, so that the direction of the movement of these organized matters is reversed. In both years the motion of water is always the same, viz., from the soil upwards to the leaves.* The summing up of the whole matter is that the nutri- * The motion of water is always upwards because the soil always contains more water than the air. Ifa plant were so situated that its roots should steadily lack water while its foliage had an excess of this liquid, it cannot be doubted that then the ‘‘sap’’ would pass down in a regular flow. In this case, oT i t ld take their normal course. never sa nutrient mat SPRY pke thant 5* 346 HOW CROPS GROW. ent substances in the plant are not absolutely confined to any path, and may move in any direction. The fact that they chiefly follow certain channels, and move in this or that direction, is plainly dependent upon the structure and arrangement of the tissues, on the sources of nutri- ment, and on the seat of growth or other action. 8 3, THE CAUSES OF MOTION OF THE VEGETABLE JUICES. Porosity of Vegetable Tissues.—Porosity is an uni- versal property of massive bodies. The word porosity implies that the molecules or smallest particles of matter are always separated from each other by a certain space. In a multitude of cases bodies are visibly porous. In many more we can see no pores, even by the aid of the highest magnifying powers of the microscope; nevertheless the fact of porosity is a necessary inference from another fact which may be observed, viz. that of absorption. A fiber of linen, to the unassisted eye, has no pores. Under the microscope we find that it is a tubular cell, the bore being much less than the thickness of the walls. By im- mersing it in water it swells, becomes more transparent, and increases in weight. If the water be colored by solu- tion of indigo or cochineal, the fiber is visibly penetrated by the dye. It is therefore porous, not only in the sense of having an interior cavity which becomes visible by a high magnifying power, but likewise in having throughout its apparently imperforate substance innumerable channels in which liquids can freely pass. In like manner, all the vegetable tissues are more or less porous and penetrable to water. Imbibition of Liquids by Porous Bodies.—Not only do the tissues of the plant admit of the access of water into Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES, 347 their pores, but they forcibly drink in or absorb this liquid, when it is presented to them in excess, until their pores are full. When the molecules of the porous body have freedom of motion, they separate from each other on imbibing a liquid; the body itself swells. Even powdered glass or fine sand perceptibly increases in bulk by imbibing water. Clay swells much more. Gelatinous silica, pectin, gum tragacanth, and boiled starch, hold a vastly greater amount of water in their pores. In case of vegetable and animal tissues, or membranes, we find a greater or less degree of expansibility from the same cause, but here the structural connection of the molecules puts a limit to their separation, and the result of saturating them with a liquid is a state of turgidity and tension, which subsides to one of yielding flabbiness when the liquid is partially removed. The energy with which vegetable matters imbibe water may be gathered from a well-known fact. In granite quarries, long blocks of stone are split out by driving plugs of dry wood into holes drilled along the desired line of fracture and pouring water over the plugs. The liquid penetrates the wood with immense force, and the toughest rock is easily broken apart. The imbibing power of different tissues and vegetable matters is widely diverse. In general, the younger or- gans or parts take up water most readily and freely. The sap-wood of trees ig far more absorbent than the heart- wood and bark. The cuticle of the leaf is often compara- tively impervious to water. Of the proximate elements we have cellulose and starch-grains able to retain, even when air-dry, 10-15°|, of water. Wax and the solid fats, as well as resins, on the contrary, do not greatly attract water, and cannot easily be wetted with it. They render cellulose, which has been impregnated with them, unab- sorbent. Digitized by Microsoft® 348 HOW CROPS GROW. Those vegetable substances which ordinarily manifest the greatest absorbent power for water, are pectin, pectic and pectosic acids, vegetable mucilage, bassorin, and al- bumin. In the living plant the protoplasmic membrane exhibits great absorbent power. Of mineral matters, gelatinous silica (Exp. 58, p. 123) is remarkable on account of its attraction for water. Not only do different substances thus exhibit unlike ad- hesion to water, but the same substance deports itself va- riously towards different liquids. 100 parts of dry ox-bladder were found by Liebig to absorb during 24 hours :— 268 parts of pure Water. 133 “ “ Saturated brine. 88 “ “ Alcohol (84°|,.) 17“ = Bone-oil. A piece of dry leather will absorb either oil or water, and apparently with equal avidity. If, however, oiled leather be immersed in water, the oil is gradually and perfectly displaced, as the farmer well knows from his ex- perience with greased boots. India-rubber, on the other hand, is impenetrable to water, while oil of turpentine is imbibed by it in large quantity, causing the caoutchouc to swell up to a pasty mass many times its original bulk. The absorbent power is influenced by the size of the pores. Other things being equal, the finer these are, the greater the foree with which a liquid is imbibed. This is shown by what has been learned from the study of a kind of pores whose effect admits of accurate measure- ment. A tube of glass, with a narrow, uniform caliber, is such a pore. In a tube of 1 motes: (about 35 af an inch) in diameter, water rises 30mm. Ina tube of ;, mil- limeter, the liquid ascends 300 mm., (about 11 inches); and in a tube of 51, mm. a column of 3,000 mm. is sus- tained. In porous bodies, like chalk, plaster stucco, closely packed ashes or starch, Jamin found that water was Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 349 absorbed with force enough to overcome the pressure of the atmosphere from three to six times; in other words— to sustain a column of water in a wide tube 100 to 200 ft. high. (Comptes Rendus, 50, p.’311.) Absorbent power is influenced by temperature. Warm water is absorbed by wood more quickly and abundantly than cold. In cold water starch does not swell to any striking or even perceptible degree, although considerable liquid is imbibed. In warm water, however, the case is remarkably altered. The starch-grains are forcibly burst open, and a paste or jelly is formed that holds many times its weight of water. (Exp. 27, p. 65.) On freezing, the particles of water are mostly withdrawn from their adhe- sion to the starch. The ascent of liquids in narrow tubes whose walls are unabsorbent, is, on the contrary, dimin- ished by a rise of temperature. _ Adhesive or Capillary Attraction.—The absorption of a liquid into the cavities of a porous body, as well as its rise in a narrow tube, are but expressions of the general fact that there is an attraction between the molecules of the liquid and the solid. In its simplest manifestation this attraction exhibits itself as Adhesion, and this term we shall employ to designate the kind of force under con- sideration. If a clean plate of glass be dipped in water, the liquid touches, and sticks to, the glass. On withdraw- ing the glass, a film of water comes away with it. Iftwo squares of glass be set up together upon a plate, so that they shall be in contact at their vertical edges on one side, and one-eighth of an inch apart on the other, it will be seen, on pouring a little water upon the plate, that this liquid rises in the space between them several inches or feet where they are in very near proximity, and curves downwards to their base where the interval is large. Capillary attraction—the common designation of the force that causes liquids to rise in fine tubes—is the same adhesion which is manifested in all the cases of .absorp- Digitized by Microsoft® 350 HOW CROPS GROW. tion, which have been alluded to. In many phenomena of absorption, however, chemical affinity appears to super- vene with more or less vigor. Adhesive attraction is not manifested universally be- tween solids and liquids, as already hinted. Glass dipped in mercury is not touched or wetted by it, and when a capillary tube is plunged in this liquid, we see no rise, but a depression within the bore. A greased glass tube de- ports itself similarly towards water. Adhesion may be a Cause of Continual Movement un- der certain circumstances. When a new cotton wick is dipped into oil, the motion of the oil may be followed by the eye, as it slowly ascends, until the pores are filled. At this moment the adhesive attraction between cotton and oil is satisfied, and motion ceases. Any cause which removes oil from the pores at the apex of the wick will un- satisfy their attraction and disturb the equilibrium which had been established between the solid and the liquid. A burning match held to the wick, by its heat destroys the oil, molecule after molecule, and this process becomes per- manent when the wick is lighted. As the pores at the base of the flame give up oil to the latter, they fill them- selves again from the pores beneath, and the motion thus set up propagates itself to the oil in the vessel below and continues as long as the flame burns or the oil holds out. In this process, the pores, if of the same material and of equal size, exert everywhere an equal attraction for the molecules of oil. The wick, above, contains indeed less oil than below, for two reasons. In the first place, gravitation, or the earth’s attraction, acts most power- fully on the oil below, and secondly, time is required for the particles of oil to pass upwards, and they cannot reach the summit as rapidly as they might be consumed. We get a further insight into the nature of this motion when we consider what happens after the oil has all been sucked up into the wick. Shortly thereafter the dimen- Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 351 sions of the flame are seen to diminish. It does not, how- ever go out, but burns on for a time with continually de- creasing vigor. When the supply of liquid in the porous body is insufficient to saturate the latter, there is still the same tendency to equalization and equilibrium. If, at last, when the flame expires, because the combustion of the oil falls below that rate which is needful to generate heat sufficient to decompose it, the wick be placed in con- tact at a single point, with another dry wick of equal mass and porosity, the oil remaining in the first will enter again into motion, will pass into the second wick, from pore to pore, until equilibrium is again restored and the oil has been shared equally between them. In case of water contained in the cavities of a porous body, evaporation from the surface of the latter becomes remotely the cause of a continual upward motion of the liquid. The exhalation of water as vapor from the foliage of a plant thus necessitates the entrance of water as liquid at the roots, and maintains a flow of it in the sap-ducts, or causes it to pass by absorption from cell to cell. Liquid Diffusion. — The movements that proceed in plants, when exhalation is out of the question, viz., such as are manifested in the stump of a vine cemented into a guage, (fig. 43, p. 248,) are not to be accounted for by capillarity or mere absorptive force under the conditions as yet noticed. To approach their elucidation we require to attend to other considerations. The particles of many different kinds of liquids attract each other. Water and alcohol may be mixed together in all proportions in virtue of their adhesive attraction. If we fill a vial with water to the rim and carefully lower it to the bottom of a tall jar of alcohol, we shall find after some hours that alcohol has penetrated the vial, and water has passed out into the jar, notwithstanding the latter liquid is considerably heavier than the former. If the wa, bg Digitized by Microsoft® 352 HOW CROPS GROW. ter be colored by indigo or cherry juice, its motion may be followed by the eye, and after a certain lapse.of time the water and alcohol will be seen to have become uni- formly mixed throughout the two vessels. This manifesta- tion of adhesive attraction is termed Liguid Diffusion. What is true of two liquids likewise holds for two solutions, i. e., for two solids made liquid by the action of asolvent. A vial filled with colored brine, or syrup, and placed in a vessel of water, will discharge its contents in- to the latter, itself receiving water in return; and this mo- tion of the liquids will not cease until the whole is uni- form in composition, i. e., until every molecule of salt or sugar is equally attracted by all the molecules of water. When several or a large number of soluble substances are placed together in water, the diffusion of each one- throughout the entire liquid will go on in the same way until the mixture is homogeneous. Liquid Diffusion may be a Cause of Continual Move- ment whenever circumstances produce continual disturb- ances in the composition of a solution or in that of a mix- ture of liquids. If into a mixture of two liquids we introduce a solid body which is able to combine chemically with, and solid- ify one of the liquids, the molecules of this liquid will be- gin to move toward the solid body from all points, and this motion will cease only when the solid is able to com- bine with no more of the one liquid, or no more remains for it to unite with. Thus, when quicklime is placed in a mixture of alcohol and water, the water is in time com- pletely condensed in the lime, and the alcohol is rendered anhydrous. Rate of Diffusion.—The rate of diffusion varies with the nature of the liquids; if solutions, with their degree of concentration and with the temperature. Colloids and Crystalloids.—There is a class of bodies whose molecules are singularly inactive in many respects, e Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 353 and have, when dissolved in water or other liquid, a very low capacity for diffusive motion. These bodies are termed Colloids,* and are characterized by swelling up or uniting with water to bulky masses (hydrates) of gelati- nous consistence, by inability to crystallize, and by feeble and poorly-defined chemical affinities. Starch, dextrin, the gums, the uncrystallized albuminoids, pectin and pectic acid, gelatin (glue), tannin and gelatinous silica, are col- loids. Opposed to these, in the properties just specified, are those bodies which erystallize, such as saccharose, glu- cose, oxalic, citric, and tartaric acids, and the ordinary salts. Other bodies which have never been seen to crystallize have the same high diffusive rate; hence the class is term- ed by Graham Crystalloids.t Colloidal bodies, when insoluble, are capable of imbib- ing liquids, and admit of liquid diffusion through their molecular interspaces. Insoluble crystalloids are, on the other hand, impenetrable to liquids in this sense. The colloids swell up more or less, often to a great bulk, from absorbing a liquid: the volume of a crystalloid remains unchanged. In his study of the rates of diffusion of various sub- -stances, dissolved in water to the extent of one per cent of the liquid, Graham found the following APPROXIMATE TIMES OF EQUAL DIFFUSION, Chlorhydric acid, crystalloid, 1. Chloride of sodium, se Qh | Sugar (cane,) i 7. Sulphate of magnesia, se ve Albumen, colloid, 49. Caramel, 8 98. * From two Greek words which signify glue-like. have already employed the word Crystalloid to distinguish the amor- nue arontnimoids fiom thee modifications or combinations which present the Pp Fi iden ria f tals, (p. 107.) This use of the word was proposed by Nigeli in oo Grangra had Deeg jt,as opposed to colloid,in 1861. It will perhaps be found that Nigeli’s crystalloids are crystalloid in Graham’s sense, Digitized by Microsoft® 354 HOW CROPS GROW. The table shows that the diffusive activity of chlor- hydric acid through water is 98 times as great as that of caramel, (see p. 73, Exp, 29). In other words, a molecule of the acid will travel 98 times as far in a given time as the molecule of caramel. Osmose,* or Membrane Diffusion.—When two miscible liquids or solutions are separated by a porous diaphragm, the phenomena of diffusion (which depend upon the mu- tual attraction of the molecules of the different liquids or dissolved substances), are complicated with those of im- bibition or capillarity, and of chemical affinity. The ad- hesive or other force which the septum is able to exert upon the liquid molecules supervenes upon the mere dif- fusive tendency, and the movements may suffer remarka- ble modifications. If we should separate pure water and a solution of common salt by a membrane upon whose substance these liquids could exert no action, the diffusion would proceed to the same result as were the membrane absent. Mole- cules of water would penetrate the membrane on one side and molecules of salt on the other, until the liquid should become alike on both. Should the water move faster than the salt, the volume of the brine would increase, and that of the water would correspondingly diminish. Were the membrane fixed in its place, a change of level of the liq- uids would occur. Graham has observed that common. salt actually diffuses into water, through a thin membrane of ox-bladder deprived of its outer muscular coating, at very nearly the same rate as when no membrane is inter- posed. Dutrochet was the first to study the phenomena of membrane diffusion. He took a glass funnel with a long and slender neck, tied a piece of bladder over the wide opening, inverted it, poured in brine until the funnel was ¢ From a Greek word meaning impulsion. Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 3855 filled to the neck, and immersed the bladder in a vessel of water. He saw the liquid rise in the narrow tube and fall in the outer vessel. He designated the passage of water into the funnel as endosmose, or inward propulsion. At the same time he found the water surrounding the funnel to acquire the taste of salt. The outward transfer of salt was his exosmose. The more general word, Osmose, ex- presses both phenomena; we may, however, employ Du- trochet’s terms to designate the direction of osmose. Osmometer.—,When the apparatus employed by Du- trochet is so constructed that the size of the narrow tube has a known relation ¢ to, is, for example, exactly ;'; that of the membrane, and the narrow tube itself is |! provided with a millimeter scale, we have the Osmometer of Graham, fig. 67. | ' The ascent or descent of the liquid in | the tube gives a measure of the amount | of osmose, provided the hydrostatic pres- sure is counterpoised by making the level of the liquid within and without equal, for which purpose water is poured into or removed from the outer vessel. | Graham designates the increase of vol- | ume in the csmometer as positive osmose, or simply osmose, and distinguishes the fall of liquid in the narrow tube as nega- Fig. 67. tive osmose. In the figure, the external vessel is intended for the reception of wa- ter. The funnel-shaped interior vessel is closed below with membrane, and stands upon a shelf of perforated zinc for support. The graduated tube fits the neck of the funnel by a ground joint. Action of the Membrane.—When the membrane itself has an attraction for one or more of the substances between which it is interposed, then the rate, amount, and even di- rection, of diffusion, may be greatly changed. d by Wlicroso’ 356 HOW CROPS GROW. Water is imbibed by the membrane of bladder much more freely than alcohol; on the other hand, a film of collodion (nitro-cellulose left from the evaporation of its solution in ether,) is penetrated much more easily by alco- hol than by water. If now these liquids be separated by bladder, the apparent flow will be towards the alcohol; but if a membrane of collodion divide them, the more rapid motion will be into the water. When a vigorous chemical action is exerted upon the membrane by the liquid or the dissolved matters, osmose is greatly heightened. In experiments with a septum of porous earthenware (porcelain biscuit,) Graham found that in case of neutral organic bodies, as sugar and alco- hol, or neutral salts, like the alkali-chlorides and nitrates, very little osmose is exhibited, i.e, the diffusion is not perceptibly greater than it would be in absence of the porous diaphragm. The acids,—oxalic, nitric, and chlorhydric,—manifest a sensible but still moderate osmose. Sulphuric and phos- phoric acids, and salts having a decided alkaline or acid reaction, viz., acid oxalate of potash, phosphate of soda, and carbonates of potash and soda, exhibit a still more vigorous osmose. For example, a solution of one part of carbonate of potash in 1,000 parts of water gains volume rapidly, and to one part of the salt that passes into the water 500 parts of water enter the solution. In all cases where diffusion is greatly modified by a membrane, the membrane itself is strongly attacked and altered, or dissolved, by the liquids. When animal mem- brane is used, it constautly undergoes decomposition and its osmotic action is exhaustible. In case earthenware is employed as a diaphragm, lime and alumina are always found in the solutions upon which it exerts osmose. Graham asserts that to induce osmose in bladder, the chemical action on the membrane must be different on the two sides, and apparently not in degree only, but also in Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 357 kind, viz., an alkaline action on the albuminoid substance of the membrane on the one side, and an acid action on the other. The water appears always to accumulate on the alkaline or basic side of the membrane. Hence with an alkaline salt, like carbonate of potash, in the osmometer, and water outside, the flow is inwards; but with an acid in the osmometer, there is negative osmose or the flow is outwards, the liquid then falling in the tube. Osmotic activity is most highly manifested in such salts as easily admit of decomposition with the setting free of a part of their acid, or alkali. Hydration of the membrane.—It is remarkable that the rapid osmose of carbonate of potash and other alkali- salts is greatly interfered with by common salt, is, in fact, reduced to almost nothing by an equal quantity of this substance. In this case it is probable that the physical . effect of the salt in diminishing the power of the membrane to imbibe water (p. 348,) operates in a sense inverse to, and neutralizes the chemical action of the carbonate. In fact, the osmose of the carbonate, as well as of all other salts, acid or alkaline, may be due to their effect in modifying the Aydration* or power of the membrane to imbibe the liquid which is the vehicle of their motion. Graham sug- gests this view as an explanation of the osmotic influence of colloid membranes, and it is not unlikely that in case of earthenware, the chemical action may exert its effect indirectly, viz., by producing hydrated silicates from the burned clay, which are truly colloid and analogous to ani- mal membranes in respect of imbibition. Graham has shown a connection between the hydrating effect of acids and alkalies on colloid membranes and their osmotic rate. “Tt is well known that fibrin, albumin and animal mem- brane,swell much more in very dilute acids and alkalies, than in pure water. On the other hand, when the proportion of * In case water is employed.ae the UH coft® 358 HOW CROPS GROW. acid or alkali is carried beyond a point peculiar to each substance, contraction of the colloid takes place. The colloids just named acquire the power of combining with an increased proportion of water and of forming higher gelatinous hydrates in consequence of contact with dilute acid or alkaline reagents. Even parchment-paper is more elongated in an alkaline solution than in pure water. When thus hydrated and dilated, the colloids present an extreme osmotic sensibility.” An illustration of membrane-diffusion which is highly instructive and easy to produce, is the following: A cavity is scooped out in a carrot, as in fig. 68, so that ( THUAN the sides remain + inch or so thick, anda quantity of dry, crushed sugar is introduced ; after some time, the previously dry sugar will be converted into a syrup by withdrawing water from the flesh of the carrot. At the same time the latter will visibly shrink from the loss of a portion of its liquid contents. In this case the small portions of juice moistening the cavity form a strong solution with the sugar in contact with them, into which water diffuses from the adjoining cells. Doubtless, also, sugar penctrates the parenchyma of the carrot. In the same manner, sugar, when sprinkled over thin- skinned fruits, shortly forms a syrup with the water which it thus withdraws from them, and salt packed with fresh meat runs to brine by the exosmose of the juices of the flesh. In these cases the fruit and the meat shrink as a result of the loss of water. Graham observed gum tragacanth, which is insoluble in water, to cause a rapid passage of water through a mem- brane in the same manner from its power of imbibition, although here there could be no exosmose or outward movement, The application of these facts and principles to explain- Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 359 ing the movements of the liquids of the plant is obvious, The cells and the tissues composed of cells furnish pre- cisely the conditions for the manifestation of motion by the imbibition of liquids and by simple diffusion, as well as by osmose. The constant disturbances needful to main- tain constant motion are to be found in fully adequate de- gree in the chemical changes that accompany the process- es of nutrition. The substances that normally exist in the vegetable cells are numerous, and they suffer remarkable transformations both in chemical constitution and in physi- cal properties. The rapidly diffusible salts that are pre- sented to the plant by the soil, and the equally diffusible sugar and organic acids that are generated in the leaf-cells, are, in part, converted into the sluggish, soluble colloids, soluble starch, dextrin, albumin, ete., or are deposited as solid matters in the cells or upon their walls, Thus the diffusible contents of the plant not only, but the mem- branes which occasion and direct osmose, are subject to perpetual alterations in their nature. More than this, the plant grows; new cells, new membranes, new proportions . of soluble and diffusible matters, are unceasingly brought into existence. Jmbibition in the cell-membranes and their solid, colloid contents, Diffusion in the liquid con- tents of the individual cells, and Osmose between the liq- uids and dissolved matters and the membranes, or colloid contents of the cells, must unavoidably take place. That we cannot follow the details of these kinds of ac- tion in the plant does not invalidate the fact of their opera- tion. The plant is so complicated and presents such a number and variety of changes in its growth, that we can never expect to understand all its mysteries. From what has been briefly explained, we can comprehend some of the more striking or obvious movements that proceed in the vegetable organism. Absorption and Osmose in Germination.—The absorp- tion of water by the seed is the first step in Germination. Digitized by Microsoft® 360 HOW CROPS GROW. The coats of the dry seed when put into the moist soil imbibe this liquid which follows the cell-walls, from cell to cell, until these membranes are saturated and swollen, At the same time these membranes occasion or permit os- mose into the cell-cavities, which, dry before, become dis- tended with liquid. The soluble contents of the cells or the soluble results of the transformation of their organized matters, diffuse from cell to cell in their passage to the ex- panding embryo. The quantity of water imbibed by the air-dry seed commonly amounts to 50 and may exceed 100 per cent. R. Hoffmann has made observations on this subject, (Vs. St., VII, p. 50.) The absorption was usually com- plete in 48 or 72 hours, and was as follows in case of certain agricultural plants :— Per cent. : Per cent. Mustard 254 tsa cess 8.0 Oath sacieeractelerd wiasentate 59.8 MUNG siete sie. cternsiercisseis oo 25.0 EL CUAD 5 siz s sispsary tierce eiessty 60.0 MOIZE cso cacvae acess vs 44.0 Kidney Bean.......... 96.1 WHER aiih ios da neonates 45.5 Hose Bei ccwaseeae 104.0 Buckwheat............. 46.8 POG baroeacdeusave ba es 106.8 Batley cc ayvcistessicameaees 48.2 CIOV ED ra sceeknseiaach aa 117.5 UPD D cc 5h 0% leh le weaves ot 51.0 Be Ct ion diradicwiieeb cleaves 120.5 BUY Cissscecetaja eusteceouges wtaumevens 57.7 White Clover.......... 126.7 Root-Action.— Absorption at the roots is unquestiona- bly an osmotic action exercised by the membrane that bounds the young rootlets and root-hairs externally. In principle it does not differ from the absorption of water by the seed. The mode in which it occasions the surpris- ing phenomena of bleeding or rapid flow of sap from a wound on the trunk or larger roots is doubtless essentially as Hofmeister first elucidated by experiment. , This flow proceeds in the ducts and intercommunicating wood-cells. Between these and the soil intervenes loose cell-tissue surrounded by a compacter epidermis. Osmose takes place in the epidermis with such energy as not only to distend to its utmost the cell-tissue, but to cause the water of the cells to jilter through their walls, and thus gain access to the ducts. The latter are formed in young Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 361 cambial tissue, and when new, are very delicate in their walls. Fig. 69 represents a simple apparatus by Sachs for imi- tating the supposed mechanism and process of Root-ac- tion. In the fig., g g represents a short, wide, open glass tube; at «, the tube is ticd over and securely closed by a piece of pig’s bladder; it is then filled with solution of sugar, and the other end, 6, is closed in similar manner by a piece of parch- ment-paper, (p. 59.) Finally a cap of India- - rubber, 4, into whose neck a narrow, bent glass tube, 7, is fixed, is tied on over 6. (These join- ings must be made very carefully and firmly.) The space within » J is left empty of liquid, and | the combination is placed in a vessel of water, as 7 in the figure. C' represents a root-cell whose exterior wall (cuti- cle,) a, is less pene- trable under pressure than its interior, 6 ; vr corresponds to a duct of vascular tis- sue, and . the sur- | rounding water takes the place of that existing in the pores of the soil. The water shortly penetrates the cell, C, distends the previously flabby membranes, under the Ac- cumulating tension filters through 6 into 7, and rises in the tube; where in Sachs’ experiment it attained a height ‘of 4 or 5 inches in 24 to 48 hours, the tube, , being about 5 millimeters wide and the area of 6, 700 sq. mm. When we consider the vast root-surface exposed to the soil, in case of a vine, and that myriads of rootlets and root-hairs unite their action in the comparatively narrow stem, we must admit that the apparatus above figured gives us 2 yery satisfactory glance into the causes of bleeding. : 16 Digitized by Microsoft® Fig. 69, 362 _ HOW CROPS GROW. Rapid Motion of Sap in the Stem.—In the stem of the plant we have commonly a resistance to root-action, so far as a flow of liquid is concerned. The ducts and sieve- cells,—in conifers, the wood-cells—though offering visibly continuous channels for the transmission of juices, are nevertheless in most cases extremely small, and while they raise liquids with enormous capillary force, they retain them with the same force, and continuous motion can only be the result of a correspondingly energetic disturbance. The root-action which can sustain a column of mercury many inches, or one of water many feet high, in a wide tube, is greatly neutralized by capillarity as we ascend the stem from the root, or the root from its young extremities. Root-action is, however, unsteady in its operation, and when it declines from any cause, it is capillarity which acts rapidly within the ducts and visible channels to supply waste by evaporation. Motion of Nutritive or Dissolved Matters; Selective Power of the Plant.—The motion of the substances that enter the plant from the soil in a state of solution and of those organized within the plant is to a great degree sep- arate from and independent of that which the water itself takes. At the same time that water is passing upwards through the plant to make good the waste by evaporation from the foliage, sugar or other carbohydrate generated in the leaves is diffusing against the water, and finding its way down to the very root-tips. This diffusion takes place mostly in the cell-tissue, and is undoubtedly greatly aided by osmose, i.e, by the action of the membranes them- selves. The very thickening of the cell-walls by the dep- osition of cellulose would indicate an attraction for the material from which cellulose is organized. The same transfer goes on simultaneously in all directions, not only into roots and stem, but into the new buds, into flowers and fruit. We have considered the tendency to equaliza- tion between two masses of liquid separated from each Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 363 other by penetrable membranes. This tendency makes valid for the organism of the plant the law that demand creates supply. In two contiguous cells, one of which contains solution of sugar, and the other, solution of ni- trate of potash, these substances must diffuse until they are mingled equally, unless, indeed, the membranes or some other substance present exerts an opposing and preponder- ating attraction. In the simplest phases of diffusion each substance is to “a certain degree independent of every other. Nitrate of potash dissolved in the water of the soil mest diffuse into the root-cells of a plant if it be absent from the sap of this root-cell and the membrane permit its passage. When the root-cell has acquired a certain proportion of nitrate of potash, a proportion equal to that in the soil-water, the nitrate cannot enter it any more. So soon as a molecule of the salt has gone on into another ceil or been removed from the sap by any chemical transformation, then a mole- cule may and must enter from without. Silica is much more abundant in grasses and cereals than in leguminous plants. In the former it exists to the extent of about 25 parts in 1,000 of the air-dry foliage, while the leaves and stems of the latter contain but 3 parts. (See Wolff’s Table in Appendix.) When these crops grow side by side, their roots are equally bathed by the same soil- water. Silica enters both alike, and, so far as regards it- self, brings the cell-contents to the same state of satura- tion that exists in the soil. The cereals are able to dispose of silica by giving it a place in the cuticular cells; the leguminous crops, on the other hand, cannot remove it from their juices; the latter remain saturated, and thus further diffusion of silica from without becomes impossi- ble except as room is made by new growth. It is in this way that we have a rational and adequate explanation of the selective power of the plant, as manifested in its de- portment towards the medium that invests its roots, The Digitized by Microsoft® 364 HOW CROPS GROW. same principles govern the transfer of matters from cell to cell, or from organ to organ, within the plant. Where- ever there is unlike composition of two miscible juices, diffusion is thereby set up, and proceeds as long as the cause of disturbance lasts, provided impenetrable mem- branes do not intervene. The rapid movement of water goes on because there is great loss of this liquid; the slow motion of silica is a consequence of the little use that arises for it in the plant. Strong chemical affinities may be overcome by osmose. Graham long ago observed the decomposition of alum (sulphate of alumina and potash,) by mere diffusion; its sulphate of potash having a higher diffusive rate than its sulphate of alumina. In the same manner acid sulphate of potash, put in contact with water, separates into sul- phate of potash and free sulphuric acid. We have seen (pp. 170-1) that the plant when vegetat- . ing in solutions of salts, is able to decompose them. It separates the components of nitrate of potash—appropriat- ing the acid and leaving the base to accumulate in the liquid. It resolves chloride of ammonium,—taking up am- monia and rejecting the chlorine. The action in these cases, we cannot definitely explain, but our analogies leave no doub’ as to the general nature of the agencies that codperat to such results, The albv:e acids in their usual form are colloid bodies and very s’ow of diffusion through liquids. They pass a membrane of nitrocellulose somewhat (Schumacher) ; but can scarcely penetrate parchment-paper. (Graham.) In the plant they are found chiefly in the sieve-cells and ad- joining parts of the cambium. Since for their production, they undoubtedly require the concourse of a carbohydrate and a nitrate, they are not unlikely generated in the cam- bium itself, for here the descending carbohydrates from the foliage come in contact with the nitrates as they rise from the soil, On the other hand, the albuminoids be- Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 365 come more diffusible in. some of their combinations. Schumacher asserts that carbonates and phosphates of the alkalies considerably inerease the osmose of albumin through membranes of nitrocellulose, (Physik der Pflanze, p. 128.) It is probable that those combinations or modi- fications of the albuminoids which occur in the soluble crystalloids of aleurone (p. 105,) and haemoglobin (p. 97,) are highly diffusible. The fact of their having the form of crystals is of itself presumptive evidence of this view, which deserves to be tested by experiment. Gaseous bodies, especially the carbonic acid and oxygen of the atmosphere, which have free access to the intercel- lular cavities of the foliage, and which are for the most part the only contents af the larger ducts, may be dis- tributed throughout the plant by osmose after having been dissolved in the sap or otherwise absorbed by the cell- contents. / Influence of the Membranes.—The sharp separation of unlike juices and soluble matters in the plant indicates the existence of a remarkable variety and range of ad- hesive attractions. In orange-colored flowers we see upon microscopic examination that this tint is produced by the united effect of yellow and red pigments which are con- tained in the cells of the petals. One cell is filled with yellow pigment, and the adjoining one with red, but these two colors are never contained in the same cell. In fruits we have coloring matters of great tinc- torial power and freely soluble in water, but they never forsake the cells where they appear, never wander into the contiguous parts of the plant. In the stems and leaves of the dandelion, lettuce, and many other plants, a white, milky, and bitter juice is contained, but it is strictly. confined to certain special channels and never visibly passes beyond them. The loosely disposed cells of the interior of leaves contain grains of chlorophyll, but this substance does not appear in the epidermal cells, Digitized by Microsoft® 366 HOW CROPS GROW. those of the stomata excepted. Sachs found that solution of indigo quickly entered the roots of a seedling bean, but required a considerable time to penetrate the stem, (p. 239.) THallier, in his experiments on the absorption of colored liquids by plants, noticed in all cases, when leaves or green stems were immersed in solution of indigo, or black-cherry juice, that these dyes readily passed into and colored the epidermis, the vascular and cambial tissue, and the parenchyma of the leaf-veins, keeping strictly to the cell-walls, but in no instance communicated any color to the cells containing chlorophyll. (Phytopathologie, Leipzig, 1868, p. 67.) We must infer that the coloring matters either cannot penetrate the cells that are occupied with chlorophyll, or else are chemically transformed into colorless substances on entering them. Sachs has shown in numerous instances that the juices of the sieve-cells and cambial tissue are alkaline, while those of the adjoining cell-tissue are acid when examined by test-paper. (Ap. Phys. der Pflanzen, p. 394.) When young and active cells are moistened with solu- tion of iodine, this substance penetrates the cellulose without producing visible change, but when it acts upon the protoplasm, the latter separates from the outer cell- wall and collapses towards the center of the cavity, as if its contents passed out, without a corresponding endos- mose being possible, (p. 224.) We may conclude from these facts that the membranes of the cells are capable of effecting and maintaining the separation of substances which have considerable attrac- tions for each other, and obviously accomplish this result by exerting themselves superior attractive or repulsive force. The influence of the membrane must vary in character with those alterations in its chemical and structural consti- tution which result from growth or any other cause. It is thus, in part, that the assimilation of external food by the Digitized by Microsoft® MECHANICAL EFFECTS OF OSMOSE ON THE PLANT. 367 plant is directed, now more to one class of proximate in- gredicnts, as the carbohydrates, and now to another, as the albuminoids, although the supplies of food presented are uniform both in total and relative quantity. If a slice of red-beet be washed and put into water, the pigment which gives it color does not readily dissolve and diffuse out of the cells, but the water remains colorless for several days. The pigment is, however, soluble in water, as is seen at once by crushing the beet, whereby the cells are forcibly broken open and their contents displaced. The cell-membranes of the uninjured root are thus appar- ently able to withstand the solvent power of water upon the pigment and to restrain the latter from diffusive mo- tion. Upon subjecting the slice of beet to cold until it is thoroughly frozen, and then placing it in warm water so that it quickly thaws, the latter is immediately and deeply tinged with red. The sudden thawing of the water with- in the pores of the cell-membrane has in fact so altered them, that they can no longer prevent the diffusive ten- dency of the vigment. (Sachs.) e g 4, MECHANICAL EFFECTS OF OSMOSE ON THE PLANT. The osmose of water from without into the cells of the plant, whether occurring on the root-surface, in the buds, or at any intermediate point where chemical changes are going on, cannot fail to exercise a great mechanical influ- ence on the phenomena of growth. Root-action, for ex- ample, being, as we have seen, often sufficient to overcome a considerable hydrostatic pressure, might naturally be expected to accelerate the development of buds and young foliage, especially since, as common observation shows, it operates in perennial plants, as the maple and grape-vine, most energetically at the season when the issue of foliage takes place. Experiment demonstrates this to be the fact. Digitized by Microsoft® 368 HOW CROPS GROW. If a twig be cut from a tree in winter and be placed in a room having a summer temperature, the buds, before dormant, shortly exhibit signs of growth, and if the cut end be immersed in water, the ~ buds will enlarge quite after the normal manner, as long as the nutrient matters of the twig last, or until the tissues at the cut begin to decay. It is the summer temperature which excites the chemical changes that result in growth. Water is needful to occupy the expanding and new-forming cells, and to be the vehicle for the translocation of nutrient matters from the wood to the buds. Water en- ters the cut stem by imbibition or capil- larity, not merely enough to replace loss by exhalation, but is sucked in by osmose acting in the growing cells. Under the same conditions as to temperature, the twigs which are connected with active roots expand earlier and more rapidly than cuttings. Artificial pressure on the water which is presented to the latter acts with an effect similar to that which the natural stress caused by the root- power exerts. This fact was demon- [ES strated by Boehm (Sitzungsberichte der ™ \< Wiener Akad., 1863) in an experiment which may be made as illustrated by the cut, fig. 70. A twig with buds is secured by means of a perforated cork into one end of a short, wide glass tube, which is closed below by another cork through which passes a narrow syphon-tube, B. The cut end of the twig is immersed in Fig. 70. ll Digitized by Microsoft® MECHANICAL £FFECTS OF OSMOSE ON THE PLANT. 369 water, JV, which is put under pressure by pouring mercury into the upper extremity of the syphon-tube. Horse- chestnut and grape twigs cut in February and March and thus treated,—the pressure of mercury being equal to 6-8 inches above the level, ,—after 4-6 weeks, unfolded their buds with normal vigor, while twigs similarly circum- stanced but without pressure opened 4-8 days later and with less appearance of strength. Fr. Schulze (arsten’s Bot. Unters., Berlin, I, 143) found that cuttings of twigs in the leaf, from the horse- chestnut, locust, willow and rose, subjected to hydrostatic pressure in the same way, remained longer turgescent and advanced much farther in development of leaves and flow- ers than twigs simply immersed in water. The amount of water in the soil influences both the ab- solute and relative quantity of this ingredient in the plant. It is a common observation that rainy spring weather causes a rank growth of grass and straw, while the yield of hay and grain is not correspondingly increased. The root-action must operate with greater effect, other things being equal, in a nearly saturated soil than in one which is less moist, and the young cells of a plant situated in the former must be subjected to greater internal stress than those of one growing in the latter—must, as a con- sequence, attain greater dimensions. Jt is not uncommon to find fleshy roots, especially radishes which have grown in hot-beds, split apart lengthwise, and Hallier mentions the fact of a sound root of petersilia splitting open after immersion in water for two or three days. (Phytopathol- ogie, p. 87.) This mechanical effect is indeed commonly conjoined with others resulting from abundant nutrition, but increased bulk of a plant without corresponding in- crease of dry matter is doubtless in great part the conse- quence of large supplies of water to the roots and its vig- orous osmose into the expanding plant, 16% Digitized by Microsoft® 370 : HOW CROPS GROW. ® § 5. DIRECTION OF VEGETABLE GROWTH. One of the most obvious peculiarities of vegetation is that the roots and stems of plants manifest’ more or less regular and often opposite directions of growth. Roots, in general, grow downwards; stems, in general, upwards, though this is by no means a universal rule, both roots and stems oftentimes manifesting either tendency in dif- ferent points or at different times of their growth. Sachs describes the following mode of observing the directive tendency of root and stem. £, fig. 71, is a glass flask containing some water; it is closed above by a cork from which a young seedling is suspended by means of a wire. The flask stands upon a plate of sand, and it is shielded from the light by a paste-board cover, Ft, the lower edge of which is forced down into the sand. The water in the flask keeps the enclosed air in a moist state. In the experiment, a sprouted nasturtium seed (Tropeolum majus) having 4g a perfectly straight descend- Ve the radicle pointing upwards __ and the plumule downwards. The next morning the seedling had the appearance of the figure. During the nicht the tip of the root curved over and the plumule sensibly raised itself. By continuing a similar experiment Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 871 for a week or more, the rootlet will grow down into the water and the stem will reach the cork. As often as the position of the seedling is reversed, so often the root and stem will reverse the direction of their growth. This ex- periment being carried on in total darkness, save during the short intervals necessary for observation, the directive tendency is shown to be independent of the action of light. Causes of Directive Power.—The direction of growth in plants appears to be for the most part the consequence of the action either of gravitation simply, as in those parts which extend directly downwards, or of internal tension overcoming gravitation, as in the parts which grow vertically upwards, or lastly of a combination (resultant) of the two forces in the parts which extend in the inter- mediate directions. The parts of a plant, whether the individual cells or ag- gregates of cells, are either in a state of tension greater or less and varying at different times, or they are entirely passive. In general, tension prevails in most parts of common plants ; the full-formed roots, stems, leaves, etc., maintain their relative positions against opposing forces, and when bent, recover themselves with more or less elasticity and donlecies. There are, however, points where tension is absent or equally exerted towards all sides, and is hence unable to give direction to growth. This may be the case where the tissue, consisting exclusively of newly-formed and im- mature cells, having delicate walls, possesses but little firmness, but is plastic like a semifluid substance. In such a condition of growth the cells follow the stress of gravi- tation or of any external force that may be accidentally applied. Influence of Gravitation.—Most young roots are in this passive condition near the tips in the region where Digitized by Microsoft® 372 HOW CROPS GROW. their elongation occurs. The new growth at these points simply obeys the attraction of the earth like any other limp or yielding mass, and a root made to grow on a horizontal plate of glass, for example, is pushed along by the expansion of its young cells and the formation of new ones until it reaches the edge, when the tip inclines down- ward as a wet string would do. If, however, as many times happens, the yielding tissue of new cells is partially or entirely enveloped by the more rigid root-cap, the downward tendency may be overcome to a corresponding degree. In this case the tip keeps more or less closely the direction already given to the root, resembling in its growth a half melted substance protuded from a tube and stiffening as it issues. The passive section of the root is translated forward as the root itself extends; the cells that to-day yield to the gravitating force, to-morrow become so rigid and firmly grown to each other as to resist the tendency of this force to coerce them to a vertical, while new cells are developed beyond, which conform to the gravitating tendency. Internal Tension.—In the upward-growing stem the different parallel and concentric tissues, viz., the cuticle, the cell-tissue of the rind, the wood-cells and ducts, and the pith, exist in a state of unequal tension. This is shown by well-known facts. If a hollow, suc- culent stem, like that supporting a dandelion blossom, be cut lengthwise, the parts curve away from each other, thus, )(, and may by a little assistance be rolled together in flat coils. The same separation of the halves may be observed in any succulent stem, provided it be fresh and turgid. It is plain then that the pith-cells of the growing stem are compressed by the cuticle; in other words the pith-cells are in a state of tension, while the cuticular cells are passively stretched by this interior strain. Closer in- vestigation indicates that the matter is somewhat compli- cated. If we strip off the “skin,” from a stalk of garden Digitized by Microsoft® CAUSES OF THE MOTION OF JUICES. 373 rhubarb (pie-plant,) we shall notice that it curves to a coil or spiral. This skin consists of the true cuticle with a coating of cell-tissue adhering. The tension of the latter and the passivity of the former occasion the curvature. Further dissection demonstrates that in general the cuti- cle, the wood-cells, and the vascular bundles, are passive, while the cell-tissues of the rind and pith, and the corre- sponding cell-tissues of the leaves, are tense. It follows from these considerations that the length of a fresh growing stem must be different from the length of its parts when separate from each other. If we divide a succulent stem lengthwise, into the pith, the wood and the rind or the corresponding parts, and accurately measure them, we shall find in fact that they differ as to length from each other and from the stem as a whole. The pith, when the wood is cut away, elongates, the wood shortens, the rind shortens still more. In the original stem the cell-tissne being united to the vascular, stretches the latter and is at the same time restrained by it. On their being cut apart, the one is free to extend and the other to shorten. Sachs gives the following comparative measurements of the stem of a tobacco plant, and of its parts after separation—the length of the stem being as- sumed as 100: Entire stem - - - - - 100 Rind = - - - - - 94,1 Wood - - - - - 98.5 Pith 7 - - - - - 102.9 Causes of Tension.—This tense condition of the con- siderably developed stem depends partly upon the unequal nutrition of the different tissues. Those parts, in fact, ex- ert tension in which rapid growth—cell-multiplication—is taking place. In the simple cell similar tension may exist, caused by the tendency of the formative layer to expand beyond the limits of the cell-wall. Another cause of tension is the different imbibing and osmotic power of the Digitized by Microsoft® 374 HOW CROPS GROW. tissues for sap. When a fresh stem or leaf loses a few per cent of water, it becomes flabby and, except so far as supported by indurated woody-tissue, has no self-sustaining power and droops from an upright direction. On dissect- ing the flabby stem lengthwise, the halves no longer curve apart, and the tension noticed in the fresh stem does not exist. The water being restored through the root, the normal turgor and original position are both recovered. In the cell-tissue, the cells themselves, so long as tension manifests itself, are fully occupied and distended with sap, and contain a highly osmotic protoplasm; the vascular tissues being the result of age and alteration in the cell- tissue, are therefore more rigid in their walls and less sensitive to mechanical strain. Upward Growth.—If a stem whose terminal parts are in a state of highly unequal tension be brought into a horizontal position, it will be found that as it makes new growth the tip curves upward until it becomes vertical. This is due to the fact that while the whole growing part elongates, the uuder side extends most rapidly. Hof meister has demonstrated that this curvature is not the result of increased tension in the active cell-tissue of the lower longitudinal section of the stem, but of increased extensibility on the part of the cuticular and vascular tis- sues of that region, for on removing the entire cuticle from a curved onion-stalk the curvature was not increased but diminished. The question now arises, why do the passive parts of the under side of the stem that is out of the vertical ad- mit of greater expansion by the stress of the rapidly growing tissues, than those of the upper? The only cause hitherto assigned is the action of gravitation on the juices of the tissues. In a stem inclined from the verti- cal, the cells of the lower side experience not only the general pressure of the water which renders the whole turgid, but, in addition, they sustain a portion of the Digitized by Microsoft® DIRECTION OF VEGETABLE GROWTH. 375 weight of the liquid in the cells above them. In other words, they are subject not only to the equal hydraulic pressure originating in the roots, but also to a slight hy- drostatic pressure from the overlying cells. This pro- duces the greater extension of the lower passive tissues, and accounts for the curvature upward. When the stem ‘becomes vertical the hydrostatic pressure is equal on both sides of the stem, and the latter is accordingly maintained in that position. (Hofmeister, Sachs.) Effect of Light.—Besides the influence of gravitation and of interior tension, that of the solar light must be re- garded, as it assists largely in producing the more com- plex phenomena of direction in the growth of plants. The explanations already given refer to the plant when unaffected by light. As is well known, the stems, leaves and roots of plants, when growing where they are un- equally illuminated, as in a window, in most cases curve or turn towards the light. More rarely is curvature away from the light observed, as in case of the stems of ivy, (Hedera helix), and the young rootlets of the mistletoe, (Viscum album). The common nasturtium, (Zropeolum majus), exhibits in its young stems inclination towards, in its older stems inclination away from, the light. Its leaves turn always towards, its roots growing in water often curve towards, often away from the light. Digitized by Microsoft® APPENDIX. TABLE I. CoMPOSITION OF THE ASH OF AGRICULTURAL PLANTS AND PRoDUCTS giving the Average of all trustworthy Analyses published up to August, 1865, by Professor Emii Wourr, of the Royal Academy of Agriculture, at Hohenheim, Wirtemberg.* = #| lasl2 E ; aes ex) 2/8] §| 8 /ESISS| 8/8 RS) i o SP Sls sSgssgis 4 aalS IS IBIS IR RS AIS I—MEADOW HAY AND GRASSES, 1,\Meadow hay................ 13 | 7.78:25.6| 7.0] 4.9/11.6] 6.2! 5.1'29.6' 8.0 QVOuNS Brass) cs. caysecc ease 1 | 9.22.56.2/ 1.8) 2.8/10.710.5 4.010. 2.0 3\Dead ripe hay............... 1 | 7.73' 7.6] 2.9) 3.4:12.9, 4.4 0.7/63.1! 5.7 4.Rye grass in flower.......... 4| 7.10 24.9) 4,2) 2.1] 7.5) 7.8, 3.8:39.6' 5.4 BUM OCD osss6is) cisieys dite tae gdyeiere’e 3) 7.01 28.5 2.7 3.7 9.4 10.8) 3.9°35.6 5.0 6 Other sweet grasses.... ....| 89 | 7.27 33.0) 1.8) 2.6) 5.5! 7.8, 4.437.6 4.1 Oats, heading out........... 6 | 9.46.41.7) 4.4) 3.5) 7.0! 8.3) 3.427.9) 4.4 1B). NAO Wer sea: 54 e-aca zeae 7 | %.23.29.0) 3.3) 3.9) 6.7 $.8 9.7,33.2, 4.0 9|Barley, heading out..... ... 5 | 8.93.38.5) 1.7| 2.9] 7.0/10.1] 2.931.931 5.6 $8. UD OWED sigs sora otras 5 | 7.04/26.2) 0.6] 3.1] 6.0; 9.8) 2.9,48.0) 3.5 11/ Winter wheat, heading out..| 2 | 9.73.34.7! 1.9) 1.5) 4.9) 7.4! 2.8 41.9) 5.3 jo! “© “in flower..... 3 | 6.99 25.7] 0.5] 2.2) 3.1) 7.3) 1.956.8) 2.8 13 Winter Rye, heading out....} 1 | 5.42 S.6) 0.3) 3.1] 7.414.7) 1.632.0) ... 14/Green Cereals, light........, 5 | 7.20 99.6! 1.5] 3.9] 6.6] 9.1) 4.1/41.4) 4.3 1 = ss es raed ree 5 | 9.21 35.6) 8.4) 4.7 8.3) 8.1 4.8,30.0 5.6 ‘Hangarian millet, green, a Gar ; 16, rans garni. a 2 | 7.23 37.4] +++ | 8.0/0.8) 5.4 3.6,29.1 6.4 II.—CLOVER AND FODDER PLANTS. 56 | 6.72'34.5) 1.6'12.2°34.0] 9.9) 3.0) 2.7) 3.7 15 | 6.01|20.8] 1.9:18.2'39.7] 9.4] 3.8] 1.9) 5.4 i 5s 23 | 6.74.29.8) 1.611.8/35.6)10.6) 3.0) 2.7) 2.9 ¢._ 35-50 se BES sa kee 18 | 7.19)46.3 1.4 4.8/27.3) 9.2) 2.21 2.5] 3.2 2 | 7.16/17.5) 7.8)10.0/32.2/14.1] 8.8] 4.5] 3.2 % } 1425.3) 1.1 5.8,48.0) 8.5) 6.1) 2.0) 1.9 2 5.30/30.4 1.7| 5.832.2)10.4 3.3, 4.0) 3.0 2 | 5.53/33.8) 1.5/1.3 31.9.10.11 4.0; 1.2) 2.8 22! Anthyllis vulneraria.......... 1 5.60)10.3 4.5) 4.6 68.9|-7.0 1.6, 2.9] 0.2 23, Green, Vetehes ocuw secs esse 2 | 8.74 42.1) 2.9) 6.8 26.312.8 3.7 1/8] 3.1 24 Green pea, in flower,..,....] 1 | 7.40/40.8} 0.2) $.2/28.7,13.2) 3.5! 2.6] 1.8 25'Green Tape, young..... .... 5 | $.07/32.3| 818] 4.5.93.1, 8.7.16.3, 3.2] 7.6 * From Prof. Wolff's Ifittlere Zusammensetzung der Asche, aller land- und Sorstwirthschafllichen wichtligen Stoffe, Stuttgart, 1865. The above Table being more complete and in most particulars more exact than the author’s means of reference enable him to construct, and being moreover likely to be the basis of calculations by agricultural chemists abroad for some years to come, has been reproduced here literally. The references and important explanations accom- panying the original, want of space precludes quoting. In the table, oxide of iron, an ingredient normally present to the extent of less than one per cent, is omitted. Chlorine is often omitted, not because absent from the plant, but from uncertainty as to its amount. Carbonic acid is also excluded in all cases for the eake of uniformity and facility of comparison. 3876 Digitized by Microsoft® APPENDIX. 377 CoMPosITION OF THE AsH OF AGRICULTURAL PLANTS AND PropuctTs. :|> S rum 3 2 §8 i g Sl as | Ss 38/88 3 ; Substance. oS Re = S g e aS 38 S $ s=|/54/38] 38) 2) 4 lSsiss = SxIN [RISIR INAS 18 IM.—ROOT CROPS. 26| Potatoes ........ 02. ee eee 81 | 3.74'59.8) 1.6] 4.5] 2.3/19.1] 6.6] 2.3) 2.8 27 Artichokes. 1 | 5.16 65.4}....] 2.7) 3.5)16.0] 3.2) ...] 2.4 Q8\/ Beets. isc seccsasaescesteenes 15 | 6.86/53.1)14.8] 5.1) 4.6) 9.6! 3.3) 3.3) 6.6 29)Sugar beets.. 44 | 4.35/49.4) 9.6] 8.9} 6.8)14.3] 4.7] 3.5] 2.0 30)/Turnips.... 15 | 8.28/39.3)11.4) 3.9)10.4)13.3)14.3] 2.4) 4.1 31)Turnips *.. 2 | 7.20/50.6] 3.8] 2.1/13.4/17.4] 6.0) 1.1] 6.4 82) Ruta-bagas 2 | 7.68/51.2] 6.7] 2.6) 9.7/15.3] 8.4} 0.5) 5.1 33 r 2 722.1) 5.3]10.7)12.5) 6.4) 2.0) 3.2 34)Chicory. . 2140.4) 7.7) 6.3) 8.7)14.5] 9.2) 6.1] 3.7 35|Sugar be -6/2£.4/11.0] 9.1/12.8] 7.6] 2.0) 0.5 F ROOT CROPS. 86)Potatoes, August... 3 | 8.92/14.5] 2.'7/16.8/39.0) 6.1] 5.6] 8.0] 4.6 37 ee October.. 1 | 5.12] 6.3) 0.8/22.6/46.2) 5.5) 5.5) 4.2) 3.0 38} BCCtS a:¢ vis. sicveseisinceeneusts 6 |15.96/29.1/21.0| 9.7)11.4) 5.1] 7.4] 4.8/11.3 39 % [17.49/22.1/16.8]/18.3/19.7| 7.4) 8.0) 3.1] 5.7 40) 16 |13.68/22.9] 7.8] 4.5)32.4| 8.9] 9.9] 8.8) 8.2 41 1 |16.87/14.4] 3.9} 4.0/33.3/10.4)11.7/10.5} 3.9 42 ] /13.57)14.1/23.1] 4.6/33.0) 4.7) 7.9) 5.6] 7.1 43 1 /12.46/60.0| 0.7] 3.2/14.3) 9.0] 9.0) 1.0] 1.7 44) 2 /10.81'48.6] 3.9) 8.3)15.3/15.8] 8.5) 1.2) 2.5 45 1 | 6.46}43.9| 5.5] 4.1]11.3)20.9111.8] 1.1] 1.2 V.—REFUSE AND MANUFACTURED PRODUCTS. 46|Sugar beet cake...........-. 7 | 3.15/36.6) 8.4) 5.6/25.3/10.2) 3.9] 6.2) 4.8 a. Common cake........ ... 2 | 3.03:25.0)12.7]... ]27.2)12.9] 5.8]..../13.0 b. ae e age ear 2 | 3.53/85.3] 9.4/11.8]27.9] 6.0] 2.3/....] 0.9 c. Residue from Centrifuga o RGhGEC ee Re ae 1 | 3.11]45.5} 9.8)... .)25.3]13.0] 6.5)....].... 47|Beet molasses........... 8 J11.28)71.1]10.5) 0.4] 6.0) 0.5) 2.1] 0.7/10.1 48|Molasses slump $........ 1 }19.02} 89.8 0.9 O:d| V2 ess | 1.6 49\Raw beet sugar.......- 1 | 1.43)/33.3/28.0]....] 8.5]..../22.9] 0.9) 5.8 50/Potato slumpf........ 1 /11.10/46.3] 6.6] 8.8} 6.2/20.0) 7.3] 3.4) 2.1 51|Potato fiber |......... 4 | 0.99/15.6]....| 7.6/47.8/23.9]....] 3.1) 1.3 52/Potato juice Y..... 2 |23.45/69.5)....| 3.5) 1.0/16.3] 3.6] 0.1] 7.5 53)/Potato skins §..... 3 | 9.59/72.0) 0.7) 6.7] 9.6] 3.4) 0.4) 2.9) 2.1 54|Fine wheat flour. . 1 | 0.47/86.0) 0.9) 8.2) 2.8)52.0)....]...-].... 55/Rye flour............ 1 | 1.97/88.4) 1.8) 8.0) 1.0/48.3 Mee) aie 56|Barley flour......... 1 | 2.83/28.8} 2.5/13.5} 2.8)47.3 ecataye | ecko 57|Barley dust **. 1 | 5,62/18.9) 1.4] 7.7) 2.5)28.9 20) esasas 58|Maize meal 1 |.... [28.8] 3.5/14.9) 6.3/45.0). adopts | hated 59|Millet meal.. 1 | 1.85]19.7| 2.3/25.3]..../47.8 ware) dane 60|Buckwheat g 2 | 0.72/25.4] 5.9/12.9) 2.3/48.1 eee | ds 61/Wheat bran........ 1 | 6.43)24.0) 0.6/16.8) 4.7/51.8 pel eee 62)Rye bran.........e eee ee 1 | $.22)27.0) 1.3/15.8} 3.5/47.9 pevnail ate 63|Brewer’s grains......... 2 | 5.17} 4.2) 0.8/10.1/11.6)38.0 32.2). ea5 G4 Malt) ccc Sesiccceseweeiems 1 | 2.78/17.3)....] 8.4) 3.8/36.5)....)88.2).... 65|Malt sprouts............ 1 | 6.56)34.9)....} 1.4) 1.5)21.0 29.5]...- 66/Wine grounds........--- 1 | 4.60/53.4) 0.5) 3.2/15.5)15.5 -+e-| 0.5 67/Grape skins.....-...-..- 2 | 4.04/49.4) 2.2) 6.1/13.0/20.8 3.5) 0.6 68|Beer.......... 1. bewiass 37.5] 7.8] 4.9] 2.2)32.7)....]10.2).... 69/Grape must... Oe jesesnce's 62.8] 0.9] 5.6] 4.9)17.7) 6.5) 1.3) 0.6 WO|Rape cake. ...0....e ees e es 2 | 6.59/24.3] @.1111.5]10.9136.9! 3.3) 8.71 0.2 * White turnips in the original, but apparently no special kind. + Probably the crowns of the roots, removed in sugar-making, ing. and distilling off the § From boiled potatoes. spirit. || Refuse of starch + The residue after ferment- manufacture. { Undiluted. #* Refuse in making barley grits. Digitized by Microsoft® 378 HOW CROPS GROW. CoMPoSITION oF THE ASH OF AGRICULTURAL PLANTS AND Propucrs. > ; ' Pe 3 BE g Substance. = SSl'S | is ; 3 514 5 asIN IR ISIR IN ISS [Sls V.—REFUSE AND MANUFACTURED PRODUCTS. "1[Linseed cake.............-.. 1 | 6.24/23.3] 1 4/15.9) 8.6]85.2) 8.4) 6.5! 0.6 72|Poppy cake... 1 (10.60|20.8] 4.5) 4.3/28.1/37.8) 2.0] 4.8] ... 73\/Walnut cake..... 1 | 5.36/33.1] .../12.2} 6.7/43.8] 1.2) 1.6] 0.2 74|Cotton seed cake............ 1 | 6.95|35.4 4.3] 4.6/48.3] 1.1] 4.0] ... VI.—STRAW. %5|Winter wheat............... 12 | 4.96/11.5] 2.9] 2.6] 6.2] 5.4] 2.9/66.3/.. %6| Winter rye.... 6 | 4.81]18.7) 3.3) 3.1) 7.7) 4.7) 1.9/58.1 v7|Winter spelt... 2 | 5.56/11.2| 0.4) 0.9) 4.8) 6.3) 1.8/71.4 78/Summer rye... 3 | 5.55/23.4) ...] 2.8] 8.9] 6.5] 2.6/55.9).... 79/Barley ...... 17 | 5.10/21.6] 4.5} 2.4) 7.6] 4.3) 3.7/53.8).... 80|Oats ............ 6 | 5.12)22.0) 5.3) 4.0) 8.2] 4.2] 3.5/48.7).... 81/Maize........... 1 | 5.49/35.3) 1.2) 5.5/10.5} 8.1] 5.2/88.0).... G2 PCAS)s orca daesadnn Q1 | 5.74/21.8) 5.3) 7.7/87.9) 7.8] 5.6) 5.7] 6.1 83/Field bean........ 4 | '7.12/44.4] 3.8) 7.8/23.1] 7.0] 0.2) 5.4/13.8 84/Garden bean...... 5 | 6.06/37.1| 6.0) 5.2/27.4| 7.8) 3.6) 4.7/ 5.2 85|Buckwheat........ 6 | 6.15/46.6] 2.2) 3.6/18.4/11.9] 5.3) 5.5) 7.7 86/ RAO. cs. eis sisi enieaiie oi 12 | 4.58 25.6/10.3) 5.7/26.5] 7.0] 7.1] 6.7/12.4 87 POPPY sevieaie cas dacireaetcinsne ve 1 | 7.86/38.0] 1.3] 6.5/30.2] 3.5] 6.1/11.4] 2.5 ETC. 73) 9.1) 1.8] 1.3] 1.9] 4.3) ... 181.2]... 9. -5] 0.3) 2.5) 2.4) 7.3) 2.3/74.2).... i -T] 0.9] 1.3)10.4; 2.0) 3.0/70.8].... : 1] 4,8) 2.6) 8.9] 0.3) 2.5/59.9].... é «1] 1.2) 4.1] 3.4) 4.4) 1.9/26.4).... i <1] 4.3] 2.8/29.6] 2.8] 4.8]17.2] 6.1 VIU.—TEXTILE PLANTS, ETC. 94 Plax i Straw) wicisice ceca ccinascie’s 8 ] 3.71/36.9| 8.1] '7.1/22.3]/11.5) 5.3] 6.0] 4.0 95|Rotted flax stems........... 2 | 2.40) 9.0] 4.8) 5.4/51.4) 5.9) 3.1/13.8).... 96|Flax fiber............06. 3 | 0.67] 3.3] 3.2) 5.4/63.6/10.8] 2.7] 6.2] 0.4 97|Entire flax plant.... 2 | 4.30)34.2) 4.8] 9.0]15.5]23.0] 4.9] 2.6] 5.9 98|Entire hemp plant... 2 | 4.60|18.3) 3.2) 9.6/43.4)11.6] 2.8] 7.6] 2.5 99|Entire hop plant.... 1 | 9.87)26.2| 3.8] 5.8)16.0/12.1) 5.4/21.5] 4.6 100/Hops.............- 12 | 6.80/37.3) 2.2] 5.5)16.9/15.1] 2.6]15.4) 3.4 10 Tobaccosii. wins asekctite sees 7 |24.08/27.4] 3.7/10.5/87.0] 3.6) 3.9] 9.6] 4.5 102 | Heath: 2 siyt6 easier sinslevcave sisiacets -2) 5.3] 8.4/18.8] 5.1] 4.4185.2) 2.1 103|Broom (Spartium). 5) 2.5/12.4/17.1] 8.6] 3.5/10.3} 2.7 104\Fern (Aspidium).... ......- 8] 4.5] 7.7]14.0] 9.7) 5.1] 6.1/10.2 105|Scouring rush (Zquésetum)... 3.2) 0.5) 2.3/12.5) 2.0) 6.3/53.8] 5.7 106|Sea-weed (Mucus)... 2. sss. £.5}24.0) 9.5/13.9) 3.1/24.0] 1.7/10.1 107|Beech leaves in autumn. 5 5.2] 0.6] 6.0/44.9] 4.2) 3.'7/33.9] 0.4 108/Oak Wega iaee. eee een 3.5] 0.6] 4.0/48.6] 8.1] 4.4/30.9).... 109/Fir “(Pinus sylvestris) 10.1]....] 9.9)41.4]16.4] 4.4/18.1) 4.4 110|Red pine leaves (Pinus Picea) 1.5]....] 2.3/15.2) 8.2] 2.8/70.1].... 111/Reed (Arundo phrag.)...[riay 8.6} 0.2] 1.2] 5.9) 2.0) 2.8)71.5].... 112/Down grass (Psamma area- 29.8] 4.0) 3.8/16.5) 7.2) 3.6/18.5).... 113 Sedge (Caren. 1 33.2) 7.3] 4.2) 5.3) 6.7) 3.3)31.5) 5.6 114/Rush (Juncus)... 36.6] 6.6] 6.4] 9.5) 6.4) 8.7/10.9/14.2 115|Bulrush (Scirpus).......... 9.7/10.3] 3.0] 7.2] 6.51 5.6/43.3).... X.—GRAINS AND SEEDS OF AGRICULTURAL PLANTS. 3.5]12.2) 3.1]46.2| 2.4 1.8]10.9] 2.7/47.5} 2.3 2.8] 8.8] 2.5/32.8) 2.3 8.8] 7.8, 3.8]20.7| 1.6 Digitized by Microsoft® 379 APPENDIX. COMPOSITION OF THE ASH OF AGRICULTURAL PLANTS AND PRoDUOTS. : Digitized by Microsoft® ert HH 00 CD HOD. 00 CPACD OEM seed + HOOD AHH oH ORO BUZlonysd ISA (ORARKRSOHAA SSS fon tin SHYSSHSS its SHSS THRE MEORNDAATH FREHTSHRSNDSOH WHARSRSTSHH DOH noms} = SERS BQ me Paha aacicree RCTS See eae umnes ee ees g eS HESS YROMR ie indrinid ietNowoencsnsro QRIrisigat ovo SONS So | a Sra eee ay ee re ee ee ee AQIS EOE Te Oe Ee enon Se. sninydng| A RASS IRONS Ease Taided ; Owed SSARRNGseItssee MRSS “poy 2 4 SENSTHSASATHASOWAHAAAGH HHA RARAASDRRAATRN ARBs 2 t Cae tar Biphasic eRe: Sere : SUNS E SEN Cece eee apap AGRIC -Loydsod| A RTGRRESSSSSABSSGASRASRRBR 5 ASSSRARTABLR SRPATEVACSE Ree. ne me “ SHASO AMNKLMGAHNSHDNONEAORNOS ES SEOSNSOSHSONS KOOSEManStR Naow wet) a a 3 OE rose Wow ctegeen tr eonee Ba oe PO Gr see ees estes eS MT) A ciciveirs Iogaggragrgdderdres A gecngrigders RAGHeSPASES EESE f < g CORENEE SH S600 St SRIGR SO AD SHOR CR Tee BIC ADEA GUARD: COCALO AD SO CUIONS OF O OEe nesouboyy WH ABHHAARAGOWSHHCHHSrASAaS A GHSBwHBSOnHMOD «HUET aHSartaa SOHS a ee ee hl cakbel cal I mon ia) Saal Pal ay OID IRS GG CODON Tt C2G0 CRON OD (CRORE IRD GR OY On CREO) SOAR SES era Gta. a ‘ PACS SS ie Ee DPOS| DD Hatt nsmsnnSnnstntaSonaaron A tirtcs : iguanas Pitt ino to O18 0d 5 he = = = SS Ie esse a H BSTHAAQrAAIQaaraAnwegrnyags G SSOWHGSEREER H SHSHSBRAABAG — OHSH Wenig | oe eee oe ee out at 1 at one od ek 2s WPId) GB ENLRUASRASAROSLAASSSISRER ~ REARASSERESS & SRAGRACRPST ORM ES 4 > te Bb On 7 O o =o = i NR -So ones «nr rat OAD s bs QIN oO) eooe “ysy RIZRSITZSASLA (ASARRSGSS IAS A AA: :B IRS is: gy BARRSRRSESS & ESRB fo quaalad a PAE SMHS MwidcdOaeiseal iwist oes lid ia st Gp orrrrdodtes | anos n S F ’ mt sash Uy A NOM ORNAARNIGHO RAM MMMM SAOAM Ar ANAAANNMaras Mee eer rin orice ‘0 0, A By B — Ear ararararar a a Sle, Beak tk ae gh AOR, sea eee BL dee eh Smy aah ae An : Sea I ae weer grok uf eats a Piiiiipiiieiipiiiiiii@ rpriins Mgiitieg tiie. a ah Ihe 20S ia Se See epodel ve Gee at ee oes ube ue pipiiBriii Bors gi. iiss ‘i ea : g Serres I ae er eae a a a te ae 1B PER eee We 4 BEDE anata Se 7 1:8 big: SE Ghie seg aes SJ n § oe 128 (GB ist ee A ‘ : ih thes 33 Bee etd alse eng s Bagii: : oO 4 | ad wagd: 3 RS Gy Ss ees tn +O . Ss “oc «Bo oS 3 m BBO R LF pues ghee get oe 1a -Ee8bac8 a @ (9g bse iggttess2 5 iigsiite gigssis Be? fe BRReaea rc) =i = 3 63g S°238 ao Bg Bb Seeks Set . ma IS WE SE go aD lina Oo "A25 3Gs © Pos . RAaEEBS Psd Src seaea = “omMdneo. % The AS ge? a HO" 8 (SBR fp: oe MP Sbae EE abes S83 igh geee2 eigQaads FS Ps 85 Bg 28RR oS id oho" 8 S4aubReegvEegeteeata BSESSEe Bush SE SE: fe BASS 893 as eeasossltag o.2 > onoo = ae) 2 Boe eid oss3s= io) OF 8o058 v5=mn = o oon o 87 nD Tain) G28 S SSGenesseeceregoiaog Sabeaam atom sa EF oe 6 Ee oeaa mee KNSSURD SEHRSURND SERSSARQNHOSD LHS Al = “ON RARRARERASSZRSRASSHRSGISSS SSESIRRRBRBS BesSseeeessss es Be Da oon Bee Oe Oe Oe Oe Be oe oe oe Bn soe ee Oe Be oe eo oo So Oe oe oe ot Oe ee Bl anne HOW CROPS GROW. 380 ComPosITION OF THE ASH OF AGRICULTURAL PLANTS AND PRODUCTS. TAIT HOMO 1UDRORWO RH RRO “aURLOpYD SSS HHdSSS HHSviSss ins incon RQAAEASERAMNDSSSS ASR anetna DOeRS OCAAMORNNSOAMDGANC19 0 RQrSw*o0 m as ee) “pwOe pig Ae oe ca ca eee ea baie WP eer Gr ee o24nydmns Connn Se Tet SD IED UO ER GD SOIER ANANCOCCOHnHS “DIOP de SERN COE Ret CO 09 8 Sete oe Se ere -Loydsoy TRIS gi ot od So 0 aH as 1G 1G 03 ESM idnvanda “ouleT gnc waranty yd ta Os ae Ree rab, eo mcolns $ rrenk id SRESRRBRRSRESRSR BEEPELSSS 7 Be CE GEG oe ee OE Eerie RUS CRO ot ppsoubngy| Sorrsarcsrdvciay BHSASH OW mn mn ben Te ae rae anor ncg iar eee ee ee DpOs GIRS POWs ro aie IBS f SadHtiogH G RASLHRSTAARSNBAD . HERSRAMSS USP) GB wt Saeigtndegacigris 4 adisinacigwed ee iit Non “Fn | ANH Sa aa he “oon wy |B SR, RELI IRRRRR B Bibs 2 bas fo yuartag J rit ft tedet et HSSSS | HF NSS : foisel ‘soshpuy AARON RNHNOoOn in Rand f0 ‘ON al : BOD han a Se ae 7 es Fog st ae ae eee Pena ee Ste yo Se oer ces ae oe eee se eee eo be ee r8 : ea arsed hebee ge ge ie 32 5 ee ae ee eae | + 18 A Se oe eS ist oe ends ee oe eae . 20 2 at ee see ae as ss 8 ae ee ae tier ea S Paz fo pee ee ce gees s 2 Cree ee er Ra Bwep Ortre . . 3B Ss & too giiigi: ee 5 BEBIPT lg igi: ee R BES Cote Heat e ag gem. BibOoas: Dds Pee - Sane ieSe GESS - S2EZ id gage SSS EREEEELE ES5S ie et a a REGERRAdEEES BARE wren moon IN corte Bo SS 4 9 Aawk on Banaeeaecase. 2266 Digitized by Microsoft® ~ 381 rr. OL APPENDIX, TABLE II. the average quantity of Water, Sulphur, Ash, and Ash-ingredients, 1,000 parts of substance, by Prof. W mm Composition oF Fresa or Air-pRY AGRICULTURAL Propucts, giving sunyds Stee ee een 2 Se Se ee Sort: 2 asec eS UaINS' Soe oec Soe ces + «Oo +s + pons : :gO-54a tS aR wt 4 ante) : wo Shaan : o tian : : i S BE 85 : 4 BeEORL OR IBE ISS: : ae : QR aa :2O0::d: Ss Bona mes Ifo 1 say : ‘A : Bakes idea 6 Ras bo Pl eet es sg e'gae tog ea : OVO° HEH Sera A Hs Ol tBu Rea 18:9 toa ERSCG SSS phe Pesos ee sos SSF ks FS BERS Se on Mean 2 + ax oZ EBS bs Og Boke & soeSsgeaq og we BS @ ShOLGEa Sa SB race tous SSUEELSRS Ssekad: BS SEESLSBSS:: SER HERS & Be Bm as ie S* = ys a + HOS aan Sasbagdes Eeeess g F SESEZaGS a4RneEyoad Digitized by Microsoft® * No special variety? + Crowns of sugar beet roots, 382 HOW CROPS GROW. CoMPOSITION OF FRESH OR AIR-DRY AGRICULTURAL PRODUCTS. S 2. (2 > ‘ Seite S18 Po) 5 QS ‘ Substance. S] ./Sl8 a $ Sax 33 g B S S/S S/S) ES] s [Seis "S/S /8 EIS IAISISIN IES [BIS ls IV.—LEAVES AND STEMS OF ROOT CROPS. Potato tops, end of August... /825} 15.6) 2.3] 0.4) 2.6] 5.1] 1.0] 0.9] 1.2) 0.7/0.6 #8 “first of October. .|770) 11.8} 0.'7/ 0.1] 2.7] 5.5) 0.6] 0.6] 0.5] 0.4]0.5 Beet tops............. cee ones 907| 14.8] 4.3) 3.1] 1.4) 1.7 0.8] 1.1) 0.7] 1.7/0.5 Sugar beet tops............... 897| 18.0) 4.0] 3.0] 3.3] 3.6) 1.3) 1.4] 0.6) 1.0}... TAU iP: LOPS ss secreceiniosniaiers wackiers 898] 14.0) 3.2) 1.1) 0.6] 4.5) 1.3] 1.4) 0.5) 7.2/0.5 Kohl-rabi tops................ 850] 25.8) 3.6] 1.0] 1.0] 8.4} 2.6] 3.0] 2.6] 1.0]... Carrot LOPS sicaiais'ssc sisiissisjsseisieis 808} 26.1} 3.7] 6.0] 1.2} 8.6) 1.2) 2.1] 1.5) 1.9/1.4 Chicory tops. selole aalanaareiets 850) 18.7/11.2/ 0.1] 0.6} 2.7] 1.7] 1.7] 0.2] 0.3)... Cabbage heads............... 885] 12.4] 6.0] 0.5) 0.4) 1.9) 2.0] 1.1] 0.1] 0.3/0.5 Cabbage stems. . 1820] 11.6] 5.11 0.6] 0.5! 1.31 2.4] 0.9] 0.21 0.41... V.—MANUFACTURED PRODUCTS AND REFUSE. Sugar beet cake.. 9.7| 3.6] 0.8] 0.5] 2.5] 1.0] 0.4] 0.6) 0.5)... a. Common cake....[machine/692} 9.3] 2.3) 1.2/....] 2.5] 1.2) 0.5}....] 1.2)... 6. Residue from Centrifugal |820) 5.6] 2.6) 0.5) ...] 1.4) 0.7) O.4/....)....)... ¢. Residue of maceration..... 885) 4.1] 1.5) 0.4) 0.5) 1.1) 0.3) 0.1)....) Of... Beet molasses.. ....... 175| 93.1/66.2] 9.8] 0.4] 5.6] 0.6] 2.0} 0.6) 9.4)... Molasses slump *, 907] 17.7] 15.9 O22 Porvel OBlecmel O.38l ies Raw beet sugar. 43) 13.7| 4.6) 3.8/....] 1.2]....] 3.1] 0.1] 0.8)... Potato slump *.. 947) 5.9) 2.7) 0.4) 0.5) 0.4] 1.2] 0.4) 0.2} 0.1).. Potato fibert... 806} 1.9} 0.3)....] 0.1] 0.9] 0.5) ...) O.1]..../.. Potato skins t.. 300] 67.1/48.3) 0.5] 4.5) 6.4) 2.8) 0.3] 1.8) 1.4]... Fine wheat flou (186) 4.1) 1.5) 0.1] 0.3) 0.1] 2.1)...0/... Jo... Rye flour....... . {142} 16.9] 6.5] 0.3) 1.4) 0.2) 8.5]....]... Barley flour.. 140} 20.0) 5.8] 0.5} 2.7) 0.6] 9.5) 0.6)... Barley dust |.. 113} 49.8] 9.4} 0.7) 3.8] 1.2/14.4)....] 9. Maize meal... 140} 9.5] 2.7] 0.3) 1.4] 0.6) 4.3)....].... Millet meal....... 140] 11.6] 2.3) 0.3) 3.0)....) 5.5) O.3/....].. Buckwheat grits.. 140) 6.2} 1.6] 0.4) 0.8} 0.1) 3.0} O.1).... Wheat bran... .. 135] 55.6/13.3) 0.3) 9.4] 2.6/28.8]....] 0.6)... Rye bran............. 131} 71.4)19.3] 0.9/11.3) 2.5)34.2)....].... Brewer's grains...... 768] 12.0] 0.5) 0.1) 1.2} 1.4] 4.6] 0.1] 3.9) Mal tess ssian cites ata 475| 14.6] 2.5]....] 1.2) 0.5) 5.3)....) 4.8]. Dried malt.......... 42/ 26.6) 4.6)... | 2.2) 1.0) 0.7). ...] 8.8). Malt sprouts... 92) 59.6/20.8)....] 0.8) 0.9/12.5) 3.8/17.7]. Wine-grounds...... 150] 16.1) 8.6) 0.1) 0.5) 2.5) 2.5) 1.21... Grape skins...... 600) 16.2) 8.0) 0.4] 1.0) 2.1) 3.4) 0.7! 0.6 Beer saci naciareaees 900] 3.9] 1.5) 0.3] 0.2) 0.1) 1.3] 0.1] 0.4) Wie: 6000 cp atcin ec. 866] 2.8] 1.8)....| 0.2! 0.2) 0.5] 0.1] 0.1]. Rape cake....... .... 150) 56.0/13.6) 0.1) 6.4) 6.1/20.7] 1.9] 4.9 Linseed cake........- 115] 55.2/12.9) 0.8] 8.8] 4.7/19.4) 1.9] 3.6 Poppy cake........... 100] 95.4/19.8) 4.3) 4.1/26.8/86.1] 1.9] 4.6). Walnut cake.,........ 136} 46.4/15.4)....| 5.7 3.1/20.3] 0.5] 0.7 115! 61.5'21.8]....1 2.6) 2.8129.5! 0.7! 2.51. VI—STRAW. 141] 42.6] 4.9] 1.2] 1.1] 2.6) 2.3) 1.2/28.9)....|1.6 154| 40.7) 7.6] 1.3) 1.3] 3.1) 1.9] 0.8/23.7]....10.9 143] 47.7| 5.3) 0.2) 0.4) 2.3) 3.0] 0.9/34.1]....)... 143| 47.6/11.1)....| 1.3) 4.4) 38.1] 1.2/26.6)....)... 140} 43.9] 9.3) 2.0) 1.1] 3.3) 1.9] 1.6/23.6).... 1.3 141] 44.0) 9.7] 2.3] 1.8] 8.6) 1.8) 1.5/21.2 1.7 140| 47.2:16.6} 0.5] 2.6] 5.0) 3.8] 2.5/17.9)....|8.9 143] 49.2)10.7) 2.6 3.8/18.6] 3.8{ 2.8] 2.8] 3.0/0.7 180) 58.4)25.9 2.2) 4.6/13.5] 4.1] 0.1) 3.1] 8.1/2.2 150] 51.5;19.1] 3.1] 2.7/14.1] 4.1] 1.8] 2.4] 2.7/2.1 * Residue from spirit manufacture. + Refuse of starch manufacture. + From boiled potatoes. | Refuse from making barley grits, . 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SIE Ce oor SRSanqagunaen 4 yaeteas PIAL’ CRAM HOM Sin crc anenydng: ores UMNSR NSSHSOMHe HSHNRAH SHAS Soscsds 189 MSHS SHHAANSOS “pV 22 bite Maa Oy 2 ee re hag as ae crea ea ese ara e = Guhta css a ie scum een en ume ne Ne A mcrae 2 od ~LoYdso"Uq Derer HONOCOCH MHOrONaG ar AMMO RNMAHOMAdt SoCOTISH MD taj SES RRSSaR | SSSRSRRE RESTEERSSZSSS B ae ae ene Siok gaa ee oe ae : ey Monet: “tad sestias Se tereriad ‘B: seu se = < F Sage we eee ace ‘8: oS. ae eee es ert dere ee ea Bi: :8ssi::2 : ene a Boat eae 2 a st eee § nen Te as Giga st: eee TBRS ILS fitagt = oan a 1a *E8 a 23 AS ‘28 ee tag Bt 3 nage 8 12 povousienen S38: BS SssaP co ea eee me 2 : - 7 Sse ‘3 Boas: : So34 (PSSESa | = PS at eae ec : 8 am 6g DiS G2 Bam ll BREA S Na SEs | BS oH ly: : R rio riiibg ERgHea:t ARETE Ses sssun ig#ag is 2 : aii fiivgg S82e22:6 Nyweyskoesatse hee aes 3 in Ete 42 ete BBAODO ID feel a8 Sa~ ore SFais BE pH Bo 1d BS nHHog Bea - Oo B28 S88 a8y wivksees SS est Syseuiek S 8: G4 QuPesoe ous ESS SREsed SSSBRSSS FSSSaShny sees PEC EET CECEEr ES 2 2 s = Os HDOoO 1 oss wat pst FARA Panos BeRRRARe Ree nnmOoReenktA | RACKS ARO Digitized by Microsoft® HOW CROPS GROW. ComMPosITION OF FRESH OR AIR-DRY AGRICULTURAL PRODUCTS. 384 “waydng ick if isk QNBOIQ au2lomy9 oooosco 2 MVNA OQ “poepey g eoocooso Pe OS 1 Re poy 4 mS See ee onunyding| oS “poy 9 | A CARRS 2 INIGIGAAGASSSSS Rx 2 f ied 3 RORHHSHHNnNe VOR Se RANE -uoydsouy 3 Me wada 5 ORM AO rr ri Gt SOSSSHHSS BxASSSSS oSnancon MOMMA WH HOC aH SONNNHroOmocoe WQS ce ee eee ee SMO aN ah te Og ee POOH IQ BeIHONME RATES espe Pose me ee ee CSSA SRA Inc ES a | CeCe, “Sees esau CEOS Pate auneT & raiSaiain te DHOSHNSSSSS OCR SO 4G) SHC ED | G2 Nat Dros wdtsoe Wer ndnno WHBMAB™ A B Se wena fa eS UI ARAR RQ CHIARA LALSS TEHRSHANA WOCSAAAH aanagA nesouboyy 8 aiciSoivict RVWGSNSSSSSS A SSHHAnHHSSS griocdnncss HeSSSSS eaisnod CO FDHDOQH hen rtd fe Aa : a fe Oe ey rt BH Lene | eee Sf PE pd INS oe | Reerese . eee eT Sone DROS! p§ SSHASSH G HORNSS PissSi WH Piiiiscsici: GHadddsdsd i tidddcd as + oe Las) ; a SQEARH NQ AONRRNVDnnASAAH a MMAR ONGoSHOM St eqnaqqEgS 2B ROR es teat Fo Sag az eg eag YSD}0T fe ards sl rESCH SH aaa A NH Sse atkitsdd PSSSHHSR WHnASSSS Gos eras fe, * fac} Oo BSHHSaS A PAHEHSSEHNS EQnqasnaHenA A SeSRandA BaQSnTSE aatarn ‘Yse esryicr # RARSSRSAII HE Hose Ronacs Qaaxawnicss Oorneidcia | “ZEAE a GRA. Gd OD 69 AEN < HOM Soa Ses San nig o nw Se B Sessnnneese & ial “aD, YHR2AZReS RFRZSRBRS S883 Hy eeeooo Seeseseseseso Seoeesseso Sco MAL) SASS = DDR D DEES |] BES J SBeseaR8 Heese Boo ra a. ee : Deve Te Se eT ee aprlaiar aract A ap esa = ied A Tercera ee cee le te ee f eed we! ORE, Pes ie ce ee eet iuiereh es MBs ee ee se. : 73 Hts ioe eae eae ae eee Beta pt LA nn? :& jai tebe Be far BPS Ae oe ete ner sh a LED chee SS ehcen ae ory : : 2 3 Pegs es aoe a Se ee oe ee 180 8 : oot 122: See it eitigi Scr notice, Thenaaber en ak ai oe ? : tt ops Bl ere ees tog el igB et lam at oe s ro if ted be sebat gge a te Toth oe, Pateiole tae Sato tee :S 8 Bost = : ig Bs his id iii: Pi1SS igs. i iit a rrr) : iJ be 5 eesgagi:: ies tare :9ag iii soe 8 geet) 2 tenes p | S2eea iS 27 RE ORB i i8 s) He Hees : (aaa re | fo (= Rees : Wesiise §: #358, 8°* 13 BgSSS 55° ii SESie Be is 18 :B ig oO toate o Pi a BEesgoag : : E@SSs aga 5 3. Badaeo SS Bae Sos Pov SSEESR iP SesgesesbSei: i883 ema OHO. oO Oo = O¢ - 5 O 3 PHoRBeo's os Sb eye Broase aboat ng asked 82 e235, F™% Sscd Te gseens: agate Sam oO n & mH DS Ma ‘a =o2 ae “4 OD nD = SRR mm suo 8 sos a a Of Me ys Saro7 > H. RRS SDS LA Ceauves HO3308 oaga 4g Book =e E 3 a> ho ESS B2 ONS OCH s HOfots 3 32° 8 BASSES SSS a: ERNE SHEE f° 8 SS EHEZVO°3 ae, ESSi'32 Aa0% BEEEa 6p & & ba 3 GGksaeeées Bocas £82238 Digitized by Microsoft® 387 ENDIX. APP PROXIMATE COMPOSITION OF AGRICULTURAL PLANTS AND PropvoTs. mains BBV ere eee lee eee oP FOL SSSSSSSSSSSSS SHAARARKCSHSRRKRAKGIYRAGRSBE | SOSSSTA ARNARNMIH OW Lag ARORABDAERSSSS ROM MMIGWH OM GWOM AIA WOWQO ARYANS HSKSSSH -NQRSHSHOS rt: 10 ‘op ‘sajDUup SESHAMAHHAAHD WOADRNGAGRSMORGDHSSHHRSOTAMY wAIbOMArI rEg e ior > a has! lary oO ol rit Ayoqwng BBHKrSBeoawwoor CEMBSRVSSRRSGRVRRSSVSBSsBSS BRVeECrPenyResesys “sprou| = DPORDASSORHAGSH WOMDSOOMOMSSOWSMWGCHRHUSSSAMIM PG —§ MEWS MONTAG |Q MAM. Pes eee ee ccaane Sees ee Ecichepeepemcnic en iGaaae nunagy Grrr rsnsnescdddonsagiedegeseng ror qeossaae : BHERAQSSHHHES WSMASHAOCSHSOMAN HS HOSNMSANSGN MRQO WWM AQ MAAS USE SHOHSSHHSSSSH SRSHGRAKRARAGRGRNRNGGOAAAGOOYE HH MBMAOCCSSNNONRVHIErErO ONDE; MaAQARSSRERNSG AOMAMIGAMMHSOUTRSMSMOOREMCSI| —§ QOH QA RAs 308 29 xR rOF ouobio| ABASnEdidewi4 gagadassassessAgaesssssses KEe“serasssssEse gy SS SSeouscesorw ony a DHBSDMDOMM MD HOOSMMIN IN OCORNHMOREO SSHEDSOQOSVSHRHANVSWS “£990 Ze Rea as CO ST Car Oe Skea aa maaan ae WOM) & BF EGRESS ERSS BSAA SA EASA AAAASAARESPREASS = ESSASSZAECTAARAR MOVES CSET ECE E ED Cece ees eke Geese eee Ca: ooo Ui fae Geis Gt ae ee 24 & e : n Ss a : pi bp sete es = Bs PRUE Se 2 BE Sco EUS aE gee eB Sa fa ne Piipeiiipipbr:priiiiic: fa oe Te ee ae RO ES SEE Pe eR AE a a tee te aie ea ie ee: “8 ek ‘a 5 ee i LP aes :8 ras 3 :g st ie an a ig 6 G 4 e etbg! er ee ete : vat ee iB Let ae te 2 oe a ae el ee ae 8 pee ea Shs : ia: ee oe en ee ake = PB EU pie! 28 oe Qt ta: : B eas GUN RD ae a aD oa a oe: aoe + a and . eo. : s 130 Ot: seope: . 2 Os 6 "Bo: O° 5OO tA IVDO se oe . E=| uae “One 4 a tii toe teiee tit Sees =o. 3 UE By ton Sa VoU (DBS SEB I: es : 2 a Sas, 1am; 18 ‘SO BSH BaRsgea:: SPP th Re Pw ee 6 a : ° = eee Bes ae Se LeRSeF OS: : ae Si ee es ee ee ae 2a ag 198: 28 SB asoneg i: 43 Ihe: IR Tes ales aoe 13 qe Oy ale wo 3 : BE vata. Cha i: et ‘oo bo Sh, ia eee ee iq rs) ai ees wea t : 2 2+ Oo# Gat 8 a) ees aA} gad : se Tagen FS 1 1Oe On Sees rs 168 to tea it ly oe: .dse ida 4 BO SSEST eg i eo [ga 225 3 208 ¢ | ee Bus] ii ig irs i PEaBS Esse 8. , BAS bea ba igsa - B°gtan. ~ig 1B Ro a PO ee BLS TOS" -s 49500 » ad :o~ Boe Sam : IPT BT ett tam aim Sarognod a a ovata tea : 3S al i : ae = - 2agga a Ls} eqgatses [sagad tHe (BSeS gee 1,498 Gan ams ra oe oes eH Ae RSE SSSaSSef2SRees sasee ZEGSSSS GRE EE: Gousree 8. BOSSE eS okey Begagwrengs a Sf RDAOS ES cm ee ase hO CRBR52 -&% 2 Pe ogGogopae aa eoFrPCsssantsoags tice bog ea SidsvooorOo epee s° * OF, pas SERS SeeseGeScebks BERGESEGSSSE5aaS44 SCHRARAR f& AMARC SRAP RAS Digitized by Microsoft® 388 HOW CROPS GROW. PROXIMATE COMPOSITION OF AGRICULTURAL PLANTS AND PRODUCTw. Substance. § ss F §¢ SSI x ae 8 Ss] 8 s(/§8 r S SS1 5 SSRERaIE REFUSE. Poppy cake. 81.6| 8.4/32.5|/87.'7[11.4) 8.1 Hemp cake.. 85.5) 4.0/27.0/36.5/22.0| 6.4 Beech out Cakes sash ort anise ona nl 84.8) 5.2/24.0/81.3)20.5) 7.5 ne 79.8) 7.7/37.3/36.9) 5.5) 7.5 Beet alisber Dab aietate qiesulavarguellacialaia sie Se mmceten a 72.5)10.8] 8.0/64.5]....].... POUILG. SGP sexier saevevadannend- aie ek reetie .6(17.1| 0.8] 0.8/15.0] 1.3] 0.3 MOTE WORD yaad aus eaaea nena oe come damna canons 93.0] 7.0]10.0/49.0/34.0/12.4 Chocolate bean 85.0) 4.0/20.0/52.0/13.0/44.0 Black China tea 79.0] 6.0] 5.0/82.0}40.0] 2.0 Green 6 -0/79.0| 6.0] 5.0/27.0/45.0] 2.0 TABLE IV. DETAILED ANALYSES OF BREAD GRAINS. & lag a Sg fe : Ait S| £ ls8lu[ssela| 8 lait Sale aigis Isle WHEAT. From Elsaas 7.2\1.2| 1.7 |1.6|14.0/Boussinganlt. ““ Saxony 1.4/2.6] 2/5 |1.6/15.6| Wunder. “America 3.8/1.2} 8.3 |1.6/10.8)Polson. , “Flanders 9.2/1.0) 1.8 |1.7/14.6) Peligot. “ Odessa 6.3/1.5) 1.7 |1.4)/15.2) ** “* Tanganrocl 7.9/1.9] 2.3 /1.6/14.8) ‘Poland 6.8/1.5) 1.7 (1.9/13.2] .‘. “Hungary, 5.4)1.1] 1.7 |1.7)14.5) “ “ Egypt 6.0|1.1] 1.8 |1.6)14.8) “ RYE. From Hessia. 8.9/0.9] 10.1 ]1.8/15.0/Fresenius “France. 10.2/1.9] 3.5 |2.2/14.1]/Payen. Saxony 0.4/2.3} 3.5 |1.4/18.3/A. Miller, ae -T| 6.4/2.1] 8.5 [3.3]16.5| Wolff, BARLEY. 10.5|50.3] 5.5/2.0] 13.6 |8.8]15. 7) Wolff. __ [18.2)53:7) 4.2/2.6] 11.5 |2.8/12.0)Polson. From Salzmiinde, Prussia] 9.3/60.4] 1.22.0] 9.7 [2.4/15.0|Grouven. OATS. 8.8]55. 2.5/6.4] 9.6 [2.7114.6]A. Miller. 15.7.2)... |. «se. {4.1]12.9| Krocker, LOS 2) 2% ie fesvetare 6.1 10.0 |2.7|12.6]) Anderson, BUCKWHEAT. Husked, from ARIE 2.6/78.9] 3.8/0.9] 1.0 ]...]12.77 Bibra. encase 3.6/76.7 eae 1.3 13.7 Mer, ° Alves ebivartaniaatien sed 13.1)..5. [3.9] 3.5 |2.5]13. 0 wonsaaew Unhusked.. eee cece eee 8.5/37.8)....]... .... |2.0/14.2[Horsford & Krocker, Mn alae trait eiareiatbleres sé 9.1/45.0] 7.10.4] 22.0 |2.4/14.0/Zenneck. MAIZE. From Saxony.. -0] 5.3/9.2) 4.9 |3.2/10.5/Hellriegel, erica -4) 2.7/4.6] 15.8 |1.7/12.0 Polson. ‘ Galacz. -5] 2.9]4.5] 20.4 /1.8/11.8 “ Switzerland +2] 6.7/8.8] 12.5 |.../10.6|Bibra. Digitized by Microsoft® APPENDIX. 389 DETAILED ANALYsrs OF BREAD GRaAINs. vlale.| [Be- Se SieS] jets] .| 8 Analyst. S§| § |SS)s [ES8| <8 Sele ale le” Sl RICE. 5) eee een 0.5]. 0.9 |0.5/14.6]Boussingault. -| 7.2179.9) 1.6]0.1] 0.5 10.9] 9.8}Polson. sil MeSliaslaced 0.2) 3.4 ios 13.%|Péligot. 5.9/73.9] 2.3]0.9] 2.0 |... |14.0]Bibra. leo (79-8 saesisll apeRes 2.2/14.0|Boussingault. 10.3/57.0|11. als: 0 .|12.2| Bibra, TABLE . DETAILED ANALYSES OF POTATOES, by Grovuven. (Agricultur-Chemie, 2te Auf., pp. 495 & 355.) Whate Potatoes, newly dug, Various Sorts. Aver- unmanured. manured. | age of 19 Analyses. Wate tins c. assis ta aneasinas mecietea! 14.95 78.01 "6.00 sn ag Bag ciata opis eGote,sheta acpaatetefs 0.47 ce US EVID yo 5io teases yp deo napa gra eed vente fe 0.04 -0: Gliadin & Mucidin (?)... ‘| 0.29 f=?) gas p=8-19 2.80 Veg. Fibrin... ise qecaes vateuens 1.31 2.02 Gum and PCD. ce cesses seat 0.76 1.56 Org, ACIS. cccicsccacerascneos 2.00 1.50 Fat. 4 0.05 0.30 13.40 15.24 1.24 1.01 1.05 0.95 100. 100. TABLE VI. DETAILED ANALYSES OF SUGAR BEETS. .| BS 18.1 § else] . | Analyst. as & [ss £8 s ERS] & [Sais8i < - Hobenheim.........cccccseseneeeene 81.5}0.87)11.90/3.47/1.33/0.80) Wolff. MoecKern ......0.cccccessececeeseer 84.1/0.82] 9.10/3.90/1.05/0.99)Ritthausen. s Pie lo) eam meine cera tart 81.7)0. 84/11. 21/3. 86/1 .36/0.94 a - Voy AOS 25. ois serdtiesoie oe seainease «--|79.5/0.90/12.07/5.09]1.52/0.88 a Bickendorf, TG WDB ic cseeincc'sisin eicinrese ale 80.0/0.70}12.90/5.00/1.20/0.70)Grouven. 0/0.68/13.37] 5.21 |0.'74|Stéckhardt. Slanstidt, 2 1bs............- eevee 180,0)0. 5 4 ; é . Lockwitz, 144 lbs.. Beeaiwaes os hee al a ee : 4%“ manured........-- 70. 2 Hi fl ss a ii - epatebieeiens 81,8)1.16/10.15] 5.7% |1.12 ss « 3y ‘¢ EBS SS wieraialesaissn 82.1]1.14] 9.25] 6.96 |1.15 ae ae a BS: eahanigeistayss. 82.5/1.05 aon 8 pole feck aa ilesia, unmanured............-.+5+ 84.4]1.14] 9. ! re eider. *manured with nitrate of soda|82.77|1.42/11.57; 3.63 {0.68 . “ man’d with phosphate of lime/84.1/1.20| 9.82 4.04 0.7% " \ Pare 81,510.95! 11.5! 3.7] 1.310.85 eee Digitized by Microsoft® HOW CROPS GROW. 390 ‘ojo ‘supTg ‘speog Ul pepnpour Aprorpy ¢ ‘prow oT[vU poywspAY sv possordxG } ‘osopONIG pus asorvyoVE x 000° O0T||OSE"S8]|099°F g(180°0)0F0'0 » 089°F ||098"% gOSE"O) Leg’E [999°O, STE T80L's “ce Wopred ‘or. “BT 000° 001| [49°98] |s09 "> {208'0, @09°0 | 90T'® |/Se8°8 fT8h°O| OE |FG"0/998' T1804’ F {i depaed ‘pow “AT 000° O0T|}098°E8| |OF9"S FFET'O)/OSL'0 | O9P°S |/009"L FOL'O} LOT'L |9F9"Ol086' T/L69°S pita “poe “OT ; “SHIM ATAS VY 000° 001||F2%"26||o98°2 f(F9T°0)/006"0 | 096°t * |]999°6 fosF'o| 6rt"0 Jece'olget'T 000° 00T|/610" LS] {0889 eo 00870 | 089°9 — |{LOT"L fE09°0} 6FO"O |x9¢-olzEs"T 000°GOT||128°L8|]Tee"9 QTE'O)/66°0 | B80'9 —/f8e8"9 fEn"O] PEO J6T9°0/099°T 00°001 ||aF"es |j9e"9 ITO) |T9°0 98°F | /es" TE fOL'O | 6E°O Ig9°0 lege Meni ae » OE 000° O0T| {908° F8] F887 ¥'0 PrL'b = |lors‘orfo99'0| += 0089 spa » CEE Ass | lap 9 SI'0) @9°0 76'P 92°0L 1F9'0 80 Ue 90's SPRAGISAY A SOs a Coe eee. 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Ils “urvunivedploy TOTAL ystpsag “CP 00°00 FE'€L cee Di pfdoqoye “ova “3p 00° 00T 20°91 98°9 ores" “TOFTOPSIO_, “Lp | HF 00° 00T 00°T RFP'0 | G4'S lee"0 Trittressss*-aiddv oqvy Out “9p 00°00T 96°FT RISO | LPO |op0 ” ” mm Sb 00° 00T OL FT fos'0 | 19 L legro en "barr tote 2 00°00 89° TT 08°T SHOULOY Ysoug ‘asivy “gp ——_——_—— "SaTdly 000°00T||9F9'9L)/FST'G {(C9T'0)| Car's FOL'D, Bed 890° TT BaEE 5 ra 2 000° 00T||066°F8)/0c9°S f(GFO"0)} ~166°0 ~—|629"F/loGe"G [ceh'O| STS"9 je9F O|eT9-O|OSa°T |SS8T DUBIOH e818] “Th “SaHIVag 000° OT|| T10"es||998"9 F(FOL‘0)/Z00'T |FF6"0/9TS"e] /eaL-stfrsL "0! e8s'6 lege'O/VOL"OlTeg"T [FIST *"SUIIT 09 ASTON ‘oS ‘oyworop L10A ‘OF 000° 0OT||996'F8||STF'S f(TL0°O)|SFE“O |L96°0)008 °F) /619'6 foes"O) Gz6"a |Zes"O\S6S O|OPT'T [PS “SUNS Lp IYSTOM “oSil Joye ‘oUlospuBE “gg *SLOOIULY Slee] F]_8] £ | BSSeis. 89 S/F] e BaISS| S |-£| & | SSPRE/$a8s) F | 8] S SyqgSS] & | Sea] * SePS /S2QF)] BF] RB] FS Seqse) [88] | PETES SESs] § | | * ood Sh ne SPPSISS8S S| ‘ se . s Sie? & SR LaqD Ad ||" SHaqIDIL aQnjosur P surysy ‘spoeg’ “suanOYT a2qnIOs (ers “A ‘ToL “vr 2 yO “wuy) ‘“SOINESAUs 0} Satpiovor ‘GLINYA JO NOILISOANWOOD Digitized by Microsoft® APPENDIX. 393 TABLE VIII FRUITS ARRANGED IN THE ORDER OF THEIR CONTENT OF SUGAR, (average,) FRESENIUS. per cent. me oO PRGGKES, iccssacrseadass Apricots. Plums. Reineclaudes Mirabelles... Raspberrie Blackberries, Strawberries, Whortleberries.. wre BDRROCAHHD ‘per cent. Currants +. 61 Prunes 6.3 Gooseberr 12 Red pears U5 Apples . 84 Sour cherr - 88 Mulberries ... - 9.2 Sweet cherries. 10.8 Grapes ......... 2 149 TABLE IX. FRUITS ARRANGED IN THE ORDER OF THEIR CONTENT OF FREE ACID EXPRESSED AS HYDRATE OF MALIC ACD, (average,) FrusEnivs. per cent. per cent. Red pears. 0 Blackberries 12 Mirabelles. -0. Sour cherrie! 3 Sweet cherr: Plums... 1.3 Peaches Whortleb 1.3 Grapes, Strawberries 1.3 Apples Gooseberries, 15 Prunes Raspberries , 15 Reineclau Mulberries... Bee) Apricots... Currants, sce ccedvecdentaeees 2.0 TABLE X. YRUITS ARRANGED ACCORDING TO THE PROPORTIONS BETWEEN ACID, SUGAR, PECTIN AND GUM, ETC., (averages,) FRESENIUS. Acid. Pectin, Gum, ete. Raspberries.. Currants..... Reineclaudes Blackberries. Whortleberries Strawberries .. Gooseberries Mulberries Mirabelles, . Apples ..... Sweet cherries. Grapes ......- Red pears..........- 1% mm m MOH MOOD a BH HEHE ee FRO TER TED DR RR Roo Co co 29 POEL CwwnNnovowvoPhpwRRontwa PODARROHOHBRWOHOOR Rroponnonccon OMe a Digitized by Microsoft® Bites HOW CROPS GROW. TABLE XI. FRUITS ARRANGED ACCORDING TO THE PROPORTIONS BETWEEN WATER, SOLUBLE MATTERS AND INSOLUBLE MATTERS, (averages,) FRESENIUS. Water. | SolubleMatters. | Insoluble Maiters. Raspberries. sciciisscias sdeme gemaeesd 100 9.1 6.9 Blackberries.. .. se 100 9.3 6.5 Strawberries 100 9.4 5.2 100 9.7 0.9 100 11.0 6.6 100 19,1. 16.9 Gooseberries........ is 100 12.2 3.6 Mirabelles..... om 100 13.0 1.5 Apricots........... A 4 100 13.3 2.1 Red Pearsrixssondsccasases ‘ 100 14.3 5.5 Peaches.... ‘ 100 14.6 2.1 PIU OSs 5). 556 te Seine Bhat 100 15.3 3.2 Sour cherries. ............. : 100 16.5 1.3 Mulberries................005 = 100 16.6 1.5 IADDICR Sa icuaevsinic bebe eednan J 100 16.9 3.6 Reineclandes.......... 0. 0 e.e.00e 100. 18.5 1.2 CHET CS sceeeernasesictiamaiaa-dare ---| 100 18.6 1.6 GUED OB ii. ssicaia. asian ve eeeereuiainie See 100 22.8 5.8 TABLE XII. PROPORTION OF OIL IN VARIOUS AIR-DRY SEEDS, according to Brrgor. (Knop’s Agricultur Chemie, p. %25.) (The air-dry seeds contain 10-12 per cent of hygroscopic water.) Colza, common... .....-........ 40-45 | Gold of Pleasure...... .......... 35 ee SCRE MTA... cece cee ne 44 | Watermelon....... -. 86 ss Pd TN Dy os sceocsciseiesing eed 40 | Charlock..... -1542 BE SWIEG AS> cn sersiveiaisiasibacdrelscern 40 | Orange...... « 40 Colocynth. « 16 Cherry ...... -- 4 Almond..... 40 Potato....... - 16 Buckthorn... 16 Currant.... » 26 Beechnul :ojissieiwiereisresrs seuaateenaais 24 Digitized by Microsoft® NEW AMERICAN FARM BOOK. ORIGINALLY BY R. LL. ALLEN, AUTHOR OF “DISEASES OF DOMESTIC ANIMALS,’ AND FORMERLY ZDITOR OF THE ‘‘ AMERICAN AGRICULTURIST.” REVISED AND ENLARGED BY LEWIS .F. ALLEN, AUTHOR OF ‘' AMERICAN CATTLE,” EDITOR OF THE ‘‘ AMERICAN SHORT-HORN HERD BOOK,” ETO. CONTENTS: InTROpDUcTION. — Tillage Husbandry —Grazing — Feeding — Breeding — Planting, etc. CHarTER I.—Soils — Classification— Description — Management — Pro- perties. Cuaptrer II.—Inorganic Manures— Mineral — Stone — Earth — Phos- phatic. CuHaPTer III.— Organic Manures — Their Composition — Animal—Ve- getable. Cuarter [V.—Irrigation and Drain- ing. Gaaeren V.—Mechanical Divisions of Soils —Spading — Plowing—Im- plements. Cuaprer VI.—The Grasses—Clovers — Meadows — Pastures — Compara- tive Values of Grasses—Implements for their Cultivation. CuartTer VII.—Grain, and its Culti- vation — Varieties — Growth—Har- vesting. CaAarTeR VIII.—Leguminous Plants —The Pea—Bean — English Field Bean—Tare or Vetch—Cultivation —Harvesting. Caarter [X.—Roots and Esculents— Varieties—Growth — Cultivation — Securing the Crops—Uses—Nutri- tive Equivalents of Different Kinds of Forage. i Carter X.—Fruits—Apples—Cider —Vinegar—Pears—Quinces—Plums Peaches — Apricots — Nectarines — Smaller Fruits—Planting—Cultiva- tion—Gathering—Preserving. | Carrer XI.—Miscellaneous Objects of Cultivation, aside from the Or- dinary Farm Crops—Broom-corn— Flax—Cotton—Hemp—Sugar Cane Sorghum—Maple Sugar —Tobacco— Indigo—Madder—Wood—Sumach— Teasel — Mustard — Hops — Castor Bean. ; CHarter XIJ.—Aids and Objects of Agriculture — Rotation of Crops, and their Effects—W eeds—Restora- tion of Worn-out Soils—Fertilizing Barren Lands—Utility of Birds— Fences—Hedges— Farm Roads— Shade Trees—Wood Lands—Time of Cutting Timber— Tools—Agri- cultural Education of the Farmer. CuHaPTER XII.—Farm Buildings— House — Barn—Sheds — Cisterns — Various other Outbuildings—Steam- ing Apparatus. CuarrER XIV.—Domestic Animals —Breeding—Anatomy—Respiration —Consumption of Food. CHAPTER XV.—Neat or Horned Cattle Devons — Herefords—Ayreshires — Galloways — Short - horns — Alder- neys or Jerseys—Dutch or Holstein —Management from Birth to Milk- ing, Labor, or Slaughter. CuaPTtER XVI.—The Dairy—Milk— Butter—Cheese—Different Kinds— Manner of Working. CHaPTteR XVII.— Sheep — Merino— Saxon—South Down—The Long- wooled Breeds—Cotswold—Lineoia — Breeding — Management — Shep- herd Dogs. CHarTER XVIII.— The Horse—De- scription of Different Breeds—Their Various Uses—Breeding—Manage- ment. CHarter XIX.—The Ass—Mule— Comparative Labor of Working Animals. CHAPTER XX. — Swine — Different Breeds — Breeding—Rearing — Fat- tening—Curing Pork and Hams. Cuaprer XXI. — Poultry—Hens, or Barn-door Fowls — Turkey — Pea- cock—Guinea Hen—Goose— Duck —Honey Bees. CHapTteR XXII.—Diseases of Ani- mals— What Authority Shall We Adopt ? — Sheep — Swine — Treat- ment and Breeding of Horses. CHAPTER XXIII.—Conclusion—Gene- ral Remarks — The Farmer who Lives by his Occupation—The Ama- teur Farmer—Sundry Useful Tables. SENT POST-PAID, PRICE $2.50. ORANCE JUDD & COQ., 245 Broadway, New-York. Digitized by Microsoft® PARI IMPLEMENTS AND MACHINERY, AND THE Principles of their Construction and Use: WITH SIMPLE AND PRACTICAL EXPLANATIONS OF THE a LAWS OF MOTION AND FORCE, AS APPLIED ON THE FARM. With 287 Illustrations. By JOHN J. THOMAS. eoges CONTENTS. PART I—MECHANICS. Caaptur I.—InrRopuction.—Value of Farm Machinery—Importance of a Knowledge of Mechanical Principles. CuaprTer I1.—General Principles of Mechanics. Carter III.—Attraction. % CuapTEerR [V.—Simple Machines, or Mechanical Powers. CHaptrerR V.—Application of Mechanical Principles in the Structure of Im- plements and Machines, CHaAPrer VI. —Friction. CuaptErR VII.—Principles of Draught. CHaPrer VIII.—Application of Labor. CuapTteR IX.—Models of Machines. CuartTeR X.—Construction and Use of Farm Implements and Machines— Implements of Tillage, Pulverizers. CuapTEeR XI.—Sowing Machines. CuaPrer XIT.—Machines for Haying and Harvesting. CuaarPTerR XIUI.—Thrashing, Grinding, and Preparing Products. PART II.—MACHINERY IN CONNECTION WITH WATER. CHAPTER J.—Hydrostatics. Cuaprer I.—Hydraulics. PART III.—MACHINERY IN CONNECTION WITH AIR. CHaprer I.—Pressure of Air. CuaPteR II.—Motion of Air. PART IV.—HEAT. CHarterR I.—Conducting Power—Expansion, Great Force of—Experiments with—Steam Engine—do. for Farms—Steam Plows—Latent Heat— Green and Dry Wood. Cuartrr II.—Radiation. APPENDIX. Apparatus for Experiments. Discharge of Water through Pipes. Velocity of Water in Pipes. Rule for Discharge of Water. Velocity of Water in Tile Drains, Glossary. Price, Post-paid, $1.50. ORANGE JUDD & CO., 245 Broadway, New-York, Digitized by Microsoft® Digitized by Microsoft® Digitized by Microsoft® Digitized by Microsoft® Digitized by Microsoft® Digitized by Microsoft®