,,histology ,,of ,,medicinal ,,plants ,,by ,,william ,,mansfield1 ,a4,m41 ,,phar4,d4 ,professor of ,histology and ,pharmacognosy1 ,college of ,pharmacy of the ,city of ,new ,york ,columbia ,university ,,total ,,issue1 ,,four ,,thousand ,,new ,,york ,,john ,,wiley ,,sons1 ,,inc4 ,,london3 ,,chapman ,,hall1 ,,limited ,copyright1 #aiaf1 by ,,william ,,mansfield ,,preface ,the object of the book is to provide a practical scientific course in vegetable histology for the use of teachers and students in schools and colleges4 ,the medicinal plants are studied in great detail because they constitute one of the most important groups of economic plants4 ,the cells found in these plants are typical of the cells occurring in the vegetable kingdom2 therefore the book should prove a valuable text-book for all students of histology4 ,the book contains much that is new4 ,in ,part ,,ii1 which is devoted largely to the study of cells and cell contents1 is a new scientific1 yet practical1 classification of cells and cell contents4 ,the author believes that his classification of bast fibres and hairs will clear up much of the confusion that students have experienced when studying these structures4 ,the book is replete with illustrations1 all of which are from original drawings made by the author4 ,as most of these illustrations are diagnostic of the plants in which they occur1 they will prove especially valuable as reference plates4 ,the material of the book is the outgrowth of the experience of the author in teaching histology at the ,college of ,pharmacy of the ,city of ,new ,york1 ,columbia ,university1 and of years of practical experience gained by examining powdered drugs in the laboratory of a large importing and exporting wholesale drug house4 ,the author is indebted to ,ernest ,leitz and ,bausch ,lomb ,optical ,company for the use of cuts of microscopic apparatus used in ,part ,i of the book4 ,the author also desires to express his appreciation to ,professor ,walter ,s4 ,cameron1 who has rendered him much valuable aid4 ,,william ,,mansfield4 ,,columbia ,,university1 ,september1 #aiaf4 ,,contents ,,part ,i ,,simple ,,and ,,compound ,,microscopes ,,and ,,microscopic ,,technic ,,chapter ,i ,,the ,,simple ,,microscopes ,,page ,simple microscopes1 forms of #d ,,chapter ,,ii ,,compound ,,microscopes ,compound microscopes1 structure of #g ,compound microscopes1 mechanical parts of #g ,compound microscopes1 optical parts of #i ,compound microscopes1 forms of #ab ,,chapter ,,iii ,,microscopic ,,measurements ,ocular micrometer #ai ,stage micrometer #ai ,mechanical stage #ba ,micrometer eye-pieces #ba ,camera lucida #bb ,drawing apparatus #bc ,microphotographic apparatus #bd ,,chapter ,,iv ,,how ,,to ,,use ,,the ,,microscope ,illumination #bf ,micro lamp #bg ,care of the microscope #bh ,preparation of specimens for cutting #bh ,paraffin imbedding oven #cj ,paraffin blocks #ca ,cutting sections #ca ,hand microtome #ca ,machine microtomes #cb ,,chapter ,v ,,reagents ,reagent set #ci ,measuring cylinder #dj ,,chapter ,,vi ,,how ,,to ,,mount ,,specimens ,temporary mounts #da ,permanent mounts #da ,cover glasses #dc ,glass slides #dd ,forceps #de ,needles #df ,scissors #df ,turntable #df ,labeling #dg ,preservation of mounted specimens #dh ,slide box #dh ,slide tray #dh ,slide cabinet #di ,,part ,,ii ,,tissues1 ,,cells ,,and ,,cell ,,contents ,,chapter ,i ,,the ,,cell ,typical cell #ec ,changes in a cell undergoing division #ee ,origin of multicellular plants #eg ,,chapter ,,ii ,,the ,,epidermis ,,and ,,periderm ,leaf epidermis #ei ,testa epidermis #fc ,plant hairs #ff ,forms of hairs #fg ,papill #fg ,unicellular hairs #fi ,multicellular hairs #gb ,periderm #hj ,cork periderm #hj ,stone cell periderm #he ,parenchyma and stone cell periderm #he ,,chapter ,,iii ,,mechanical ,,tissues ,bast fibres #hi ,crystal bearing bast fibres #ij ,porous and striated bast fibres #ib ,porous and non-striated bast fibres #if ,non-porous and striated bast fibres #if ,non-porous and non-striated bast fibres #if ,occurrence of bast fibres in powdered drugs #ajc ,wood fibres #ajd ,collenchyma cells #ajf ,stone cells #aji ,endodermal cells #aaf ,hypodermal cells #aah ,,chapter ,,iv ,,absorption ,,tissue ,root hairs #aba ,,chapter ,v ,,conducting ,,tissue ,vessels and tracheids #abf ,annular vessels #abg ,spiral vessels #abg ,sclariform vessels #abh ,reticulate vessels #aca ,pitted vessels #aca ,pitted vessels with bordered pores #aca ,sieve tubes #acf ,sieve plate #ach ,medullary bundles1 rays and cells #ach ,medullary ray bundle #aci ,the medullary ray #aci ,the medullary ray cell #ada ,structure of the medullary ray cells #adb ,arrangement of the medullary ray cells in the medullary ray #adb ,latex tubes #adb ,parenchyma #add ,cortical parenchyma #adg ,pith parenchyma #adg ,leaf parenchyma #aej ,aquatic plant parenchyma #aej ,wood parenchyma #aej ,phloem parenchyma #aej ,palisade parenchyma #aej ,,chapter ,,vi ,,aerating ,,tissue ,water pores #aea ,stomata #aea ,relation of stomata to the surrounding cells #aed ,lenticels #aeg ,intercellular spaces #aeh ,,chapter ,,vii ,,synthetic ,,tissue ,photosynthetic tissue #afc ,glandular tissue #afd ,glandular hairs #afd ,secretion cavities #aff ,schizogenous cavities #afh ,lysigenous cavities #afh ,schizo-lysigenous cavities #afh ,,chapter ,,viii ,,storage ,,tissue ,storage cells #agc ,storage cavities #agf ,crystal cavities #agf ,mucilage cavities #agf ,latex cavities #agf ,oil cavity #agh ,glandular hairs as storage organs #agh ,storage walls #agi ,,chapter ,,ix ,,cell ,,contents ,chlorophyll #ahb ,leucoplastids #ahc ,starch grains #ahc ,occurrence #ahd ,outline #ahe ,size #ahe ,hilum #ahe ,nature of hilum #ahh ,inulin #aid ,mucilage #aid ,hesperidin #aif ,volatile oil #aif ,tannin #aif ,aleurone grains #aig ,structure of aleurone grains #aig ,form of aleurone grains #aig ,description of aleurone grains #aih ,tests for aleurone grains #aih ,crystals #bjj ,micro-crystals #bjj ,raphides #bjj ,rosette crystals #bjb ,solitary crystals #bje ,cystoliths #baj ,forms of cystoliths #baj ,tests for cystoliths #bae ,,part ,,iii ,,histology ,,of ,,roots1 ,,rhizomes1 ,,stems1 ,,barks1 ,,woods1 ,,flowers1 ,,fruits ,,and ,,seeds ,,chapter ,i ,,roots ,,and ,,rhizomes ,cross-section of pink root #bai ,cross-section of ruellia root #bai ,cross-section of spigelia rhizome #bbc ,cross-section of ruellia rhizome #bbf ,powdered pink root #bbg ,powdered ruellia root #bbg ,,chapter ,,ii ,,stems ,herbaceous stems #bcc ,cross-section1 spigelia stem #bcc ,ruellia stem #bce ,powdered horehound #bcg ,powdered spurious horehound #bcg ,insect flower stems #bda ,,chapter ,,iii ,,woody ,,stems ,buchu stem #bdb ,mature buchu stem #bdb ,powdered buchu stem #bde ,,chapter ,,iv ,,barks ,white pine bark #bdh ,powdered white pine bark #bej ,,chapter ,v ,,woods ,cross-section quassia #bed ,radial-section quassia #bed ,tangential-section quassia #beh ,,chapter ,,vi ,,leaves ,klip buchu #bfj ,powdered klip buchu #bfb ,mountain laurel #bfd ,trailing arbutus #bfd ,,chapter ,,vii ,,flowers ,pollen grains #bgj ,non-spiny-walled pollen grains #bgc ,spiny-walled pollen grains #bgc ,stigma papill #bgd ,powdered insect flowers #bgh ,open insect flowers #bhj ,powdered white daisies #bhb ,,chapter ,,viii ,,fruits ,celery fruit #bhe ,,chapter ,,ix ,,seeds ,sweet almonds #bhi ,,chapter ,x ,,arrangement ,,of ,,vascular ,,bundles ,types of fibro-vascular bundles #bib ,radial vascular bundles #bib ,concentric vascular bundles #bie ,collateral vascular bundles #bie ,bi-collateral vascular bundles #bih ,open collateral vascular bundles #bih ,,index ,,table ,,of ,,illustrations ,,page ,,fig4 #a4 ,tripod ,magnifier #d ,,fig4 #b4 ,watchmaker's ,loupe #d ,,fig4 #c4 ,folding ,magnifier #d ,,fig4 #d4 ,reading ,glass #d ,,fig4 #e4 ,steinheil ,aplanatic ,lens #e ,,fig4 #f4 ,dissecting ,microscope #e ,,fig4 #g4 ,compound ,microscope of ,robert ,hooke #h ,,fig4 #h4 ,compound ,microscope #aj ,,fig4 #i4 ,abb ,condenser #aa ,,fig4 #aj4 #aa ,,fig4 #aa4 #aa ,,fig4 #ab4 ,objectives #aa ,,fig4 #ac4 #ab ,,fig4 #ad4 #ab ,,fig4 #ae4 ,eye-,pieces4 #ab ,,fig4 #af4 ,pharmacognostic ,microscope #ab ,,fig4 #ag4 ,research ,microscope #ad ,,fig4 #ah4 ,special ,research ,microscope #ad ,,fig4 #ai4 ,greenough ,binocular ,microscope #ae ,,fig4 #bj4 ,polarization ,microscope #af ,,fig4 #ba4 ,ocular ,micrometer #ai ,,fig4 #bb4 ,stage ,micrometer #ai ,,fig4 #bc4 ,micrometer ,eye-,piece #bj ,,fig4 #bd4 ,micrometer ,eye-,piece #ba ,,fig4 #be4 ,mechanical ,stage #bb ,,fig4 #bf4 ,camera ,lucida #bb ,,fig4 #bg4 ,camera ,lucida #bb ,,fig4 #bh4 ,drawing ,apparatus #bc ,,fig4 #bi4 ,microphotographic ,apparatus #bd ,,fig4 #cj4 ,micro ,lamp #bg ,,fig4 #ca4 ,paraffin-embedding ,oven #cj ,,fig4 #cb4 ,paraffin ,blocks #ca ,,fig4 #cc4 ,hand ,microtome #ca ,,fig4 #cd4 ,hand ,cylinder ,microtome #cd ,,fig4 #ce4 ,hand ,table ,microtome #cd ,,fig4 #cf4 ,base ,sledge ,microtome #ce ,,fig4 #cg4 ,minot ,rotary ,microtome #cf ,,fig4 #ch4 ,reagent ,set #ci ,,fig4 #ci4 ,measuring ,cylinder #dj ,,fig4 #dj4 ,staining ,dish #dj ,,fig4 #da4 ,round ,cover ,glass #dd ,,fig4 #db4 ,square ,cover ,glass #dd ,,fig4 #dc4 ,rectangular ,cover ,glass #dd ,,fig4 #dd4 ,glass ,slide #dd ,,fig4 #de4 ,histological ,forceps #de ,,fig4 #df4 ,forceps #de ,,fig4 #dg4 ,sliding-pin ,forceps #de ,,fig4 #dh4 ,dissecting ,needle #df ,,fig4 #di4 ,scissors #df ,,fig4 #ej4 ,scalpels #dg ,,fig4 #ea4 ,turntable #dg ,,fig4 #eb4 ,slide ,box #dh ,,fig4 #ec4 ,slide ,tray #dh ,,fig4 #ed4 ,slide ,cabinet #di ,,plate #a ,,the ,,onion ,,root #ef ,,plate #b ,,leaf ,,epidermis #fj ,,plate #c ,,leaf ,,epidermis #fa ,,plate #d ,,testa ,,epidermal ,,cells #fd ,,plate #e ,,testa ,,cells #fe ,,plate #f ,,papill #fh ,,plate #g ,,unicellular ,,solitary ,,hairs #gj ,,plate #h ,,clustered ,,unicellular ,,hairs #ga ,,plate #i ,,multicellular ,,uniseriate ,,non-,,branched ,,hairs #gc ,,plate #aj ,,multicellular ,,multiseriate ,,non-,,branched ,,hairs #ge ,,plate #aa ,,multicellular ,,uniseriate ,,branched ,,hairs #gf ,,plate #ab ,,non-,,glandular ,,multicellular ,,hairs #gh ,,plate #ac ,,multicellular ,,multiseriate ,,branched ,,hairs #gi ,,plate #ad ,,multicellular ,,multiseriate ,,branched ,,hairs #ha ,,plate #ae ,,multicellular ,,multiseriate ,,branched ,,hairs #hb ,,plate #af ,,periderm ,,of ,,cascara ,,sagrada 7,rhamnus purshiana1 ,d4,c47 #hd ,,plate #ag ,,mandrake ,,rhizome and ,,white ,,cinnamon #hf ,,plate #ah ,,periderm ,,of ,,white ,,oak 7,quercus alba1 ,l47 #hg ,,plate #ai ,,crystal-,,bearing ,,fibres ,,of ,,barks #ia ,,plate #bj ,,crystal-,,bearing ,,fibres ,,of ,,barks #ic ,,plate #ba ,,crystal-,,bearing ,,fibres ,,of ,,leaves #id ,,plate #bb ,,branched ,,bast ,,fibres #ie ,,plate #bc ,,porous ,,and ,,striated ,,bast ,,fibres #ig ,,plate #bd ,,porous ,,and ,,non-,,striated ,,bast ,,fibres #ih ,,plate #be ,,non-,,porous ,,and ,,striated ,,bast ,,fibres #ii ,,plate #bf ,,non-,,porous ,,and ,,non-,,striated ,,bast ,,fibres #aja ,,plate #bg ,,groups ,,of ,,bast ,,fibres #ajb ,,plate #bh ,,wood ,,fibres #aje ,,plate #bi ,,catnip ,,stem and ,,motherwort ,,stem #ajg ,,plate #cj ,,collenchyma ,,cells #ajh ,,plate #ca ,,branched ,,stone ,,cells #aaj ,,plate #cb ,,porous ,,and ,,striated ,,stone ,,cells #aac ,,plate #cc ,,porous ,,and ,,non-,,striated ,,stone ,,cells #aad ,,plate #cd ,,cinnamon1 ,,ruella ,,root1 ,,cascara and ,,cinnamon #aae ,,plate #ce ,,cross-,,sections ,,of ,,endodermal ,,cells ,,of #aag ,,plate #cf ,,longitudinal ,,sections ,,of ,,endodermal ,,cells #aai ,,plate #cg ,,hypodermal ,,cells #abj ,,plate #ch ,,cross-,,section ,,of ,,sarsaparilla ,,root 7,smilax officinalis1 ,kunth7 #abc ,,plate #ci ,,root ,,hairs 7,fragments7 #abd ,,plate #dj ,,annular ,,and ,,spiral ,,vessels #abi ,,plate #da ,,spiral ,,vessels #acj ,,plate #db ,,sclariform ,,vessels #acb ,,plate #dc ,,reticulate ,,vessels #acc ,,plate #dd ,,pitted ,,vessels #acd ,,plate #de ,,vessels #ace ,,plate #df ,,sieve ,,tube #acg ,,plate #dg ,,radial ,,longitudinal ,,section ,,of ,,white ,,sandalwood 7,santalum album1 ,l47 #adj ,,plate #dh ,,kava-,,kava ,,root and ,,white ,,pine ,,bark #adc ,,plate #di ,,black ,,indian ,,hemp and ,,black ,,indian ,,hemp ,,root #ade ,,plate #ej ,,latex ,,vessels #adf ,,plate #ea ,,parenchyma ,,cells #adh ,,plate #eb ,,grindelia ,,stem 7longitudinal7 and ,,grindelia ,,stem 7cross-section7 #adi ,,plate #ec ,,aconite ,,stem and ,,peppermint ,,stem #aeb ,,plate #ed ,,types ,,of ,,stoma #aec ,,plate #ee ,,leaf ,,epidermi ,,with ,,stoma #aee ,,plate #ef ,,belladonna ,,leaf1 ,,deer ,,tongue ,,leaf and ,,white ,,pine ,,leaf #aef ,,plate #eg ,,elder ,,bark #aei ,,plate #eh ,,intercellular ,,air ,,spaces #afj ,,plate #ei ,,irregular ,,intercellular ,,air ,,spaces #afa ,,plate #fj ,,glandular ,,hairs #afe ,,plate #fa ,,stalked ,,glandular ,,hairs #afg ,,plate #fb ,,calamus ,,rhizome and ,,white ,,pine ,,bark #afi ,,plate #fc ,,canella ,,alba ,,bark and ,,klip ,,buchu ,,leaf #agj ,,plate #fd ,,bitter ,,orance ,,peel and ,,white ,,pine ,,leaf #aga ,,plate #fe ,,cinnamon1 ,,calumba1 ,,parenchyma1 ,,sarsaparilla1 ,,leptandra1 ,,quebracho1 ,,blackberry #agd ,,plate #ff ,,mucilage ,,and ,,resin #age ,,plate #fg ,,cross-,,section ,,of ,,skunk-,,cabbage ,,leaf 7,symplocarpus ftidus1 ,l4 ,nutt47 #agg ,,plate #fh ,,reserve ,,cellulose #ahj ,,plate #fi ,,reserve ,,cellulose #aha ,,plate #gj ,,starch #ahf ,,plate #ga ,,starch #ahg ,,plate #gb ,,starch #ahi ,,plate #gc ,,starch #aij ,,plate #gd ,,starch #aia ,,plate #ge ,,starch ,,grains #aib ,,plate #gf ,,starch ,,masses #aic ,,plate #gg ,,inulin 7,inula helenium1 ,l47 #aie ,,plate #gg;a ,,aleurone ,,grains #aii ,,plate #gh ,,micro-,,crystals #bja ,,plate #gi ,,raphides #bjc ,,plate #hj ,,rosette ,,crystals #bjd ,,plate #ha ,,inclosed ,,rosette ,,crystals #bjf ,,plate #hb ,,solitary ,,crystal #bjg ,,plate #hc ,,solitary ,,crystals #bjh ,,plate #hd ,,solitary ,,crystals #bji ,,plate #he ,,solitary ,,crystals #baa ,,plate #hf ,,solitary ,,crystals #bab ,,plate #hg ,,rosette ,,crystals ,,and ,,solitary ,,crystals ,,occurring ,,in #bac ,,plate #hh ,,cystoliths #bad ,,plate #hi ,,cross-,,section ,,of ,,root ,,of ,,spigelia ,,marylandica1 ,l4 #bbj ,,plate #ij ,,ruellia ,,root 7,ruellia ciliosa1 ,pursh474 #bbb ,,plate #ia ,,cross-,,section ,,of ,,rhizome ,,of ,,spigelia ,,marylandica1 ,l4 #bbd ,,plate #ib ,,cross-,,section ,,of ,,rhizome ,,of ,,ruellia ,,ciliosa1 ,pursh4 #bbe ,,plate #ic ,,powdered ,,spigelia ,,marylandica1 ,l4 #bbh ,,plate #id ,,powdered ,,ruellia ,,ciliosa1 ,pursh4 #bbi ,,plate #ie ,,cross-,,section ,,of ,,stem ,,of ,,spigelia ,,marylandica1 ,l4 #bcd ,,plate #if ,,cross-,,section ,,of ,,stem ,,of ,,ruellia ,,ciliosa1 ,pursh4 #bcf ,,plate #ig ,,powdered ,,horehound 7,marrubium vulgare1 ,l74 #bch ,,plate #ih ,,spurious ,,horehound 7,marrubium peregrinum1 ,l47 #bci ,,plate #ii ,,powdered ,,insect ,,flower ,,stems 7,chrysanthemum cinerariifolium1 ,trev41 ,vis47 #bdj ,,plate #ajj ,,cross-,,section ,,of ,,buchu ,,stems 7,barosma betulina ,berg41 ,barth1 and ,wendl47 #bdc ,,plate #aja ,,buchu ,,stem and ,,leptandra ,,rhizome #bdd ,,plate #ajb ,,powdered ,,buchu ,,stems 7,barosma betulina ,berg41 ,barth4 and ,wendl474 #bdf ,,plate #ajc ,,cross-,,section ,,of ,,unrossed ,,white ,,pine ,,bark 7,pinus strobus1 ,l47 #bdi ,,plate #ajd ,,powdered ,,white ,,pine ,,bark 7,pinus strobus1 ,l47 #bea ,,plate #aje ,,cross-,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #bee ,,plate #ajf ,,tangential ,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #bef ,,plate #ajg ,,radial ,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #beg ,,plate #ajh ,,cross-,,section ,,of ,,klip ,,buchu ,,just ,,over ,,the ,,vein #bfa ,,plate #aji ,,powdered ,,klip ,,buchu #bfc ,,plate #aaj ,,cross-,,section ,,mountain ,,laurel 7,kalmia latifolia1 ,l47 #bfe ,,plate #aaa ,,cross-,,section ,,trailing ,,arbutus ,,leaf 7,epiga repens1 ,l47 #bff ,,plate #aab ,,powdered ,,insect ,,flower ,,leaves #bfh ,,plate #aac ,,smooth-,,walled ,,pollen ,,grains #bga ,,plate #aad ,,spiny ,,walled ,,pollen ,,grains #bgb ,,plate #aae ,,papill #bge ,,plate #aaf ,,papill ,,of ,,stigmas #bgf ,,plate #aag ,,papill ,,of ,,stigmas #bgg ,,plate #aah ,,powdered ,,closed ,,insect ,,flower #bgi ,,plate #aai ,,powdered ,,open ,,insect ,,flower #bha ,,plate #abj ,,powdered ,,white ,,daisies 7,chrysanthemum leucanthemum1 ,l47 #bhc ,,plate #aba ,,cross-,,section ,,of ,,celery ,,fruit 7,apium graveolens1 ,l47 #bhf ,,plate #aba ,,cross-,,section ,,of ,,celery ,,fruit 7,apium graveolens1 ,l47 #bhf ,,plate #abc ,,cross-,,section ,,sweet ,,almond ,,seed #bij ,,plate #abd ,,cross-,,section ,,of ,a ,,radial ,,vascular ,,bundle ,,of ,,skunk ,,cabbage ,,root #bic ,,plate #abe ,,cross-,,section ,,of ,a ,,phloem-,,centric ,,bundle ,,of ,,calamus ,,rhizome 7,acorus calamus1 ,l47 #bid ,,plate #abf ,,cross-,,section ,,of ,a ,,closed ,,collateral ,,bundle ,,of ,,mandrake ,,stem 7,podophyllum peltatum1 ,l47 #bhf ,,plate #abg ,,bi-,,collateral ,,bundle ,,of ,,pumpkin ,,stem 7,curcurbita pepo1 ,l47 #big ,part ,i ,,simple ,,and ,,compound ,,microscopes ,,and ,,microscopic ,,technic ,,chapter ,i ,,the ,,simple ,,microscopes ,the construction and use of the simple microscope 7magnifiers7 undoubtedly date back to very early times4 ,there is sufficient evidence to prove that spheres of glass were used as burning spheres and as magnifiers by people antedating the ,greeks and ,romans4 ,the simple microscopes of to-day have a very wide range of application and a corresponding variation in structure and in appearance4 ,simple microscopes are used daily in classifying and studying crude drugs1 testing linen and other cloth1 repairing watches1 in reading1 and identifying insects4 ,the more complex simple microscopes are used in the dissection and classification of flowers4 ,the watchmaker's loupe1 the linen tester1 the reading glass1 the engraver's lens1 and the simplest folding magnifiers consist of a double convex lens4 ,such a lens produces an erect1 enlarged image of the object viewed when the lens is placed so that the object is within its focal distance4 ,the focal distance of a lens varies according to the curvature of the lens4 ,the greater the curvature1 the shorter the focal distance and the greater the magnification4 ,the more complicated simple microscope consists of two or more lenses4 ,the double and triple magnifiers consist of two and three lenses respectively4 ,when an object is viewed through three lenses1 the magnification is greater than when viewed through one or two lenses1 but a smaller part of the object is magnified4 ,,forms ,,of ,,simple ,,microscopes ,,tripod ,,magnifier ,the tripod magnifier 7,fig4 #a7 is a simple lens mounted on a mechanical stand4 ,the tripod is placed over the object and the focus is obtained by means of a screw which raises or lowers the lens1 according to the degree it is magnified4 ,,watchmaker',s ,,loupe ,the watchmaker's loupe 7,fig4 #b7 is a one-lens magnifier mounted on an ebony or metallic tapering rim1 which can be placed over the eye and held in position by frowning or contracting the eyelid4 ,illustration3 ,,fig4 #a4--,tripod ,magnifier ,illustration3 ,,fig4 #b4--,watchmaker's ,loupe ,,folding ,,magnifier ,the folding magnifier 7,fig4 #c7 of one or more lenses is mounted in such a way that1 when not in use1 the lenses fold up like the blade of a knife1 and when so folded are effectively protected from abrasion by the upper and lower surfaces of the folder4 ,illustration3 ,,fig4 #c4--;,folding ,magnifier ,illustration3 ,,fig4 #d4--,reading ,glass ,,reading ,,glasses ,reading glasses 7,fig4 #d7 are large simple magnifiers1 often six inches in diameter4 ,the lens is encircled with a metal band and provided with a handle4 ,illustration3 ,,fig4 #e4--,steinheil ,aplanatic ,lens ,,steinheil ,,aplanatic ,,lenses ,steinheil aplanatic lenses 7,fig4 #e7 consist of three or four lenses cemented together4 ,the combination is such that the field is large1 flat1 and achromatic4 ,these lenses are suitable for field1 dissecting1 and pocket use4 ,when such lenses are placed in simple holders1 they make good dissecting microscopes4 ,illustration3 ,,fig4 #f4--;,dissecting ,microscope ,,dissecting ,,microscope ,the dissecting microscope 7,fig4 #f7 consists of a ,steinheil lens and an elaborate stand1 a firm base1 a pillar1 a rack and pinion1 a glass stage1 beneath which there is a groove for holding a metal plate with one black and one white surface4 ,the nature of the object under observation determines whether a plate is used4 ,when the plate is used and when the object is studied by reflected light it is sometimes desirable to use the black and sometimes the white surface4 ,the mirror1 which has a concave and a plain surface1 is used to reflect the light on the glass stage when the object is studied by transmitted light4 ,the dissecting microscope magnifies objects up to twenty diameters1 or twenty times their real size4 ,,chapter ,,ii ,,compound ,,microscopes ,the compound microscope has undergone wonderful changes since #affg1 the days of ,robert ,hooke4 ,when we consider the crude construction and the limitations of ,robert ,hooke's microscope1 we marvel at the structural perfection and the unlimited possibilities of the modern instrument4 ,the advancement made in most sciences has followed the gradual perfection of this instrument4 ,the illustration of ,robert ,hooke's microscope 7,fig4 #g7 will convey to the mind more eloquently than words the crudeness of the early microscopes1 especially when it is compared with the present-day microscopes4 ,,structure ,,of ,,the ,,compound ,,microscope ,the parts of the compound microscope 7,fig4 #h7 may be grouped into--first1 the mechanical1 and1 secondly1 into the optical parts4 ,,the ,,mechanical ,,parts #a4 ,the foot is the basal part1 the part which supports all the other mechanical and optical parts4 ,the foot should be heavy enough to balance the other parts when they are inclined4 ,most modern instruments have a three-parted or tripod-shaped base4 #b4 ,the pillar is the vertical part of the microscope attached to the base4 ,the pillar is joined to the limb by a hinged joint4 ,the hinges make it possible to incline the microscope at any angle1 thus lowering its height4 ,in this way1 short1 medium1 and tall persons can use the microscope with facility4 ,the part of the pillar above the hinge is called the limb4 ,the limb may be either straight or curved4 ,the curved form is preferable1 since it offers a more suitable surface to grasp in transferring from box or shelf to the desk1 and vice versa4 ,illustration3 ,,fig4 #g4--;,compound ,microscope of ,robert ,hooke #c4 ,the stage is either stationary or movable1 round or square1 and is attached to the limb just above the hinge4 ,the upper surface is made of a composition which is not easily attacked by moisture and reagents4 ,the centre of the stage is perforated by a circular opening4 #d4 ,the sub-stage is attached below the stage and is for the purpose of holding the iris diaphragm and ,abb condenser4 ,the raising and lowering of the sub-stage are accomplished by a rack and pinion4 #e4 ,the iris diaphragm1 which is held in the sub-stage below the ,abb condenser1 consists of a series of metal plates1 so arranged that the light entering the microscope may be cut off completely or its amount regulated by moving a control pin4 #f4 ,the fine adjustment is located either at the side or at the top of the limb4 ,it consists of a fine rack and pinion1 and is used in focusing an object when the low-power objective is in position1 or in finding and focusing the object when the high-power objective is in position4 #g4 ,the coarse adjustment is a rack and pinion used in raising and lowering the body-tube and in finding the approximate focus when either the high- or low-power objective is in position4 #h4 ,the body-tube is the path traveled by the rays of light entering the objectives and leaving by the eye-piece4 ,to the lower part of the tube is attached the nose-piece1 and resting in its upper part is the draw-tube1 which holds the eye-piece4 ,on the outer surface of the draw-tube there is a scale which indicates the distance it is drawn from the body-tube4 #i4 ,the nose-piece may be simple1 double1 or triple1 and it is protected from dust by a circular piece of metal4 ,double and triple nose-pieces may be revolved1 and like the simple nose-piece they hold the objectives in position4 ,,the ,,optical ,,parts #a4 ,the mirror is a sub-stage attachment one surface of which is plain and the other concave4 ,the plain surface is used with an ,abb condenser when the source of light is distant1 while the concave surface is used with instruments without an ,abb condenser when the source of light is near at hand4 ,illustration3 ,,fig4 #h4--;,compound ,microscope ,eyepiece ,draw ,tube ,body ,tube ,coarse ,adjustment ,revolving ,nosepiece for three ,objectives ,fine ,adjustment ,stage ,objectives ,limb ,abbi ,condenser ,iris ,diaphragm ,hinge for ,inclining ,substage ,attachment ,mirror ,pillar ,foot #b4 ,the ,abb condenser 7,fig4 #i7 is a combination of two or more lenses1 arranged so as to concentrate the light on the specimen placed on the stage4 ,the condenser is located in the opening of the stage1 and its uppermost surface is circular and flat4 ,illustration3 ,,fig4 #i--;,abb ,condenser #c4 ,objectives 7,figs4 #aj1 #aa1 and #ab74 ,there are low1 medium1 and high-power objectives4 ,the low-power objectives have fewer and larger lenses1 and they magnify least1 but they show more of the object than do the high-power objectives4 ,there are three chief types of objectives3 ,first1 dry objectives2 second1 wet objectives1 of which there are the water-immersion objectives2 and third1 the oil-immersion objectives4 ,the dry objectives are used for most histological and pharmacognostical work4 ,for studying smaller objects the water objective is sometimes desirable1 but in bacteriological work the oil-immersion objective is almost exclusively used4 ,the globule of water or oil1 as the case may be1 increases the amount of light entering the objective1 because the oil and water bend many rays into the objective which would otherwise escape4 ,illustration3 ,,fig4 #aj4 ,illustration3 ,,fig4 #aa4 ,illustration3 ,,fig4 #ab4 ,objectives4 #d4 ,eye-pieces 7,figs4 #ac1 #ad1 and #ae7 are of variable length1 but structurally they are somewhat similar4 ,the eye-piece consists of a metal tube with a blackened inner tube4 ,in the centre of this tube there is a small diaphragm for holding the ocular micrometer4 ,in the lower end of the tube a lens is fastened by means of a screw4 ,this1 the field lens1 is the larger lens of the ocular4 ,the upper1 smaller lens is fastened in the tube by a screw1 but there is a projecting collar which rests1 when in position1 on the draw-tube4 ,illustration3 ,,fig4 #ac4 ,illustration3 ,,fig4 #ad4 ,illustration3 ,,fig4 #ae4 ,eye-,pieces4 ,the longer the tube the lower the magnification4 ,for instance1 a two-inch ocular magnifies less than an inch and a half1 a one-inch less than a three-fourths of an inch1 etc4 ,the greater the curvature of the lenses of the ocular the higher will be the magnification and the shorter the tube-length4 ,,forms ,,of ,,compound ,,microscopes ,the following descriptions refer to three different models of compound microscopes3 one which is used chiefly as a pharmacognostic microscope1 one as a research microscope stand1 while the third type represents a research microscope stand of highest order1 which is used at the same time for taking microphotographs4 ,illustration3 ,,fig4 #af4--,pharmacognostic ,microscope ,,pharmacognostic ,,microscope ,the pharmacognostic microscope 7,fig4 #af7 is an instrument which embodies only those parts which are most essential for the examination of powdered drugs1 bacteria1 and urinary sediments4 ,this microscope is provided with a stage of the dimensions #aje #aje mm4 ,this factor and the distance of #hj mm4 from the optical centre to the handle arm render it available for the examination of even very large objects and preparations1 or preparations suspended in glass dishes4 ,the stand is furnished with a side micrometer1 a fine adjustment having knobs on both sides1 thereby permitting the manipulation of the micrometer screw either by left or right hand4 ,the illuminating apparatus consists of the ,abb condenser of numerical aperture of #a4bj1 to which is attached an iris diaphragm for the proper adjustment of the light4 ,a worm screw1 mounted in connection with the condenser1 serves for the raising and lowering of the condenser1 so that the cone of illuminating pencils can be arranged in accordance to the objective employed and to the preparation under observation4 ,the objectives necessary are those of the achromatic type1 possessing a focal length of #af4b mm4 and #c mm4 ,oculars which render the best results in regard to magnification in connection with the two objectives mentioned are the ,huyghenian eye-pieces ,,ii and ,,iv so that magnifications are obtained varying from #fb to #fbe4 ,it is advisable1 however1 to have the microscope equipped with a triple revolving nose-piece for the objectives1 so that provision is made for the addition of an oil-immersion objective at any time later should the microscope become available for bacteriological investigations4 ,,the ,,research ,,microscope ,the research microscope used in research work 7,fig4 #ag7 must be equipped more elaborately than the microscope especially designed for the use of the pharmacognosist4 ,while the simple form of microscope is supplied with the small type of ,abb condenser1 the research microscope is furnished with a large illuminating apparatus of which the iris diaphragm is mounted on a rack and pinion1 allowing displacement obliquely to the optical centre1 also to increase resolving power in the objectives when observing those objects which cannot be revealed to the best advantage with central illumination4 ,another iris is furnished above the condenser2 this iris becomes available the instant an object is to be observed without the aid of the condenser1 in which case the upper iris diaphragm allows proper adjustment of the light4 ,the mirror1 one side plane1 the other concave1 is mounted on a movable bar1 along which it can be slid--another convenience for the adjustment of the light4 ,the microscope stage of this stand is of the round1 rotating and centring pattern1 which permits a limited motion to the object slide3 ,the rotation of the microscope stage furnishes another convenience in the examination of objects in polarized light1 allowing the preparation to be rotated in order to distinguish the polarization properties of the objects under observation4 ,illustration3 ,,fig4 #ag4--,research ,microscope ,illustration3 ,,fig4 #ah4--,special ,research ,microscope ,,special ,,research ,,microscope ,a special research microscope of the highest order 7,fig4 #ah7 is supplied with an extra large body tube1 which renders it of special advantage for micro-photography4 ,otherwise in its mechanical equipment it resembles very closely the medium-sized research microscope stand1 with the exception that the stand is larger in its design1 therefore offering universal application4 ,in regard to the illuminating apparatus1 it is advisable to mention that the one in the large research microscope stand is furnished with a three-lens condenser of a numerical aperture of #a4dj1 while the medium-sized research stand is provided with a two-lens condenser of a numerical aperture of #a4bj4 ,the stage of the microscope is provided with a cross motion--the backward and forward motion of the preparation is secured by rack and pinion1 while the side motion is controlled by a micrometric worm screw4 ,in cases where large preparations are to be photographed1 the draw-tube with ocular and the slider in which the draw-tubes glide are removed to allow the full aperture of wide-angle objectives to be made use of4 ,illustration3 ,,fig4 #ai4--;,greenough ,binocular ,microscope ,,binocular ,,microscope ,the ,greenough binocular microscope1 as shown in ,fig4 #ai1 consists of a microscope stage with two tubes mounted side by side and moving on the same rack and pinion for the focusing adjustment4 ,either tube can be used without the other4 ,the oculars are capable of more or less separation to suit the eyes of different observers4 ,in each of the drub-like mountings1 near the point where the oculars are introduced1 porro-prisms have been placed1 which erect the image4 ,this microscope gives most perfect stereoscopic images1 which are erect instead of inverted1 as in the monocular compound microscopes4 ,the ,greenough binocular microscope is especially adapted for dissection and for studying objects of considerable thickness4 ,,polarization ,,microscope ,the polarization microscope 7,fig4 #bj7 is used chiefly for the examination of crystals and mineral sections as well as for the observation of organic bodies in polarized light4 ,it can1 however1 also be used for the examination of regular biological preparations4 ,illustration3 ,,fig4 #bj4--,polarization ,microscope ,if compared with the regular biological microscope1 the polarization microscope is found characteristic of the following points3 it is supplied with a polarization arrangement4 ,the latter consists of a polarizer and analyzer4 ,the polarizer is situated in a rotating mount beneath the condensing system4 ,the microscope1 of which the diagram is shown1 possesses a triple 8,ahrens0 prism of calcite4 ,the entering light is divided into two polarized parts1 situated perpendicularly to each other4 ,the so-called 8ordinary0 rays are reflected to one side by total reflection1 which takes place on the inner cemented surface of the triple prism1 allowing the so-called 8extraordinary0 rays to pass through the condenser4 ,if the prism is adjusted to its focal point1 it is so situated that the vibration plane of the extra-ordinary rays are in the same position as shown in the diagram of the illustration4 ,the analyzer is mounted within the microscope-tube above the objective4 ,situated on a sliding plate1 it can be shifted into the optical axis whenever necessary4 ,the analyzer consists of a polarization prism after ,glan-,thompson4 ,the polarization plane of the active extraordinary rays is situated perpendicularly to the plane as shown in the diagram4 ,the polarization prisms are ordinarily crossed4 ,in this position the field of the microscope is darkened as long as no substance of a double refractive index has been introduced between the analyzer and polarizer4 ,in rotating the polarizer up to the mark #ij1 the polarization prisms are mounted parallel and the field of the microscope is lighted again4 ,immediately above the analyzer and attached to the mounting of the analyzer a lens of a comparatively long focal length has been placed in order to overcome the difference in focus created by the introduction of the analyzer into the optical rays4 ,the condensing system is mounted on a slider1 and1 furthermore1 can be raised and lowered along the optical centre by means of a rack-and-pinion adjustment4 ,if lowered sufficiently1 the condensing system can be thrown to the side to be removed from the optical rays4 ,the condenser consists of three lenses4 ,the two upper lenses are separately mounted to an arm1 which permits them to be tilted to one side in order to be removed from the optical rays4 ,the complete condenser is used only in connection with high-power objectives4 ,as far as low-power objectives are concerned1 the lower condensing lens alone is made use of1 and the latter is found mounted to the polarizer sleeve4 ,below the polarizer and above the lower condensing lens an iris diaphragm is found4 ,the microscope table is graduated on its periphery1 and1 furthermore1 carries a vernier for more exact reading4 ,the polarization microscope is not furnished with an objective nose-piece4 ,every objective1 however1 is supplied with an individual centring head1 which permits the objective to be attached to an objective clutch-changer1 situated at the lower end of the microscope-tube4 ,the centring head permits the objectives to be perfectly centred and to remain centred even if another objective is introduced into the objective clutch-changer4 ,at an angle of #de degrees to the polarization plane of polarizer and analyzer1 a slot has been provided1 which serves for the introduction of compensators4 ,between analyzer and ocular1 another slot is found which permits the ,amici-,bertrand lens to be introduced into the optical axis4 ,the slider for the ,bertrand lens is supplied with two centring screws whereby this lens can be perfectly and easily centred4 ,the ,bertrand lens serves the purpose of observing the back focal plane of the microscope objective4 ,in order to allow the ,bertrand lens to be focused1 the tube can be raised and lowered for this purpose4 ,an iris diaphragm is mounted above the ,bertrand lens4 ,if the ,bertrand lens is shifted out of the optical axis1 one can observe the preparation placed upon the microscope stage and1 depending on its thickness or its double refraction1 the interference color of the specimen4 ,this interference figure is called the orthoscopic image and1 accordingly1 one speaks of the microscope as being used as an 8orthoscope40 ,after the ,bertrand lens has been introduced into the optical axis1 the interference figure is visible in the back focal plane of the objective4 ,each point of this interference figure corresponds to a certain direction of the rays of the preparation itself4 ,this arrangement permits observation of the change of the reflection of light taking place in the preparation1 this in accordance with the change of the direction of the rays4 ,this interference figure is called the conoscopic image1 and1 accordingly1 the microscope is used as a 8conoscope40 ,many types of polarization microscopes have been constructed2 those of a more elaborate form are used for research investigations2 others of smaller design for routine investigations4 ,,chapter ,,iii ,,microscopic ,,measurements ,in making critical examinations of powdered drugs1 it is frequently necessary to measure the elements under observation1 particularly in the case of starches and crystals4 ,illustration3 ,,fig4 #ba4--,ocular ,micrometer ,,ocular ,,micrometer ,microscopic measurements are made by the ocular micrometer 7,fig4 #ba74 ,this consists of a circular piece of transparent glass on the centre of which is etched a one- or two-millimeter scale divided into one hundred or two hundred divisions respectively4 ,the value of each line is determined by standardizing with a stage micrometer4 ,,stage ,,micrometer ,illustration3 ,,fig4 #bb4--,stage ,micrometer ,the stage micrometer 7,fig4 #bb7 consists of a glass slide upon which is etched a millimeter scale divided into one hundred equal parts or lines3 each line has a value of one hundredth of a millimeter4 ,,standardization ,,of ,,ocular ,,micrometer ,,with ,,low-,,power ,,objective ,having placed the ocular micrometer in the eye-piece and the stage micrometer on the centre of the stage1 focus until the lines of the stage micrometer are clearly seen4 ,then adjust the scales until the lines of the stage micrometer are parallel with and directly under the lines of the ocular micrometer4 ,ascertain the number of lines of the stage micrometer covered by the one hundred lines of the ocular micrometer4 ,then calculate the value of each line of the ocular4 ,this is done in the following manner3 ,if the one hundred lines of the ocular cover seventy-five lines of the stage micrometer1 then the one hundred lines of the ocular micrometer are equivalent to seventy-five one-hundredths1 or three-fourths1 of a millimeter4 ,one line of the ocular micrometer will therefore be equivalent to one-hundredth of seventy-five one-hundredths1 or 4#jjge part of a millimeter1 and as a micron is the unit for measuring microscopic objects1 this being equivalent to one one-thousandth of a millimeter1 the value of each line of the ocular will therefore be #g4e microns4 ,illustration3 ,,fig4 #bc4--,micrometer ,eye-,piece ,with the high-power objective in place1 ascertain the value of each line of the ocular4 ,if one hundred lines of the ocular cover only twelve lines of the stage micrometer1 then the one hundred lines of the ocular are equivalent to twelve one-hundredths of a millimeter1 the value of one line being equivalent to one one-hundredth of twelve one-hundredths1 or twelve ten-thousandths of a millimeter1 or 4#jjab1 or #a4b4 ,it will therefore be seen that objects as small as a thousandth of a millimeter can be accurately measured by the ocular micrometer4 ,in making microscopic measurements it is only necessary to find how many lines of the ocular scale are covered by the object4 ,the number of lines multiplied by the equivalent of each line will be the size of the object in microns1 or micromillimeters4 ,illustration3 ,,fig4 #bd4--,micrometer ,eye-,piece ,,micrometer ,,eye-,,pieces ,micrometer eye-pieces 7,figs4 #bc and #bd7 may be used in making measurements4 ,these eye-pieces with micrometer combinations are preferred by some workers1 but the ocular micrometer will meet the needs of the average worker4 ,,mechanical ,,stages ,moving objects by hand is tiresome and unsatisfactory1 first1 because of the possibility of losing sight of the object under observation1 and secondly1 because the field cannot be covered so systematically as when a mechanical stage is used for moving slides4 ,the mechanical stage 7,fig4 #be7 is fastened to the stage by a screw4 ,the slide is held by two clamps4 ,there is a rack and pinion for moving the slide to left or right1 and another rack and pinion for moving the slide forward and backward4 ,illustration3 ,,fig4 #be4 ,mechanical ,stage ,,camera ,,lucida ,the camera lucida is an optical mechanical device for aiding the worker in making drawings of microscopic objects4 ,the instrument is particularly necessary in research work where it is desirable to reproduce an object in all its details4 ,in fact1 all reproductions illustrating original work should be made by means of the camera lucida or by microphotography4 ,illustration3 ,,fig4 #bf4--;,camera ,lucida ,illustration3 ,,fig4 #bg4--;,camera ,lucida ,a great many different types of camera lucidas or drawing apparatus are obtainable1 varying from simple-inexpensive to complex-expensive forms4 ,figs4 #bf1 #bg1 and #bh show simple and complex forms4 ,illustration3 ,,fig4 #bh4--;,drawing ,apparatus ,,microphotographic ,,apparatus ,the microphotographic apparatus 7,fig4 #bi71 as the name implies1 is an apparatus constructed in such a manner that it may be attached to a microscope when we desire to photograph microscopic objects4 ,it consists of a metal base and a polished metal pillar for holding the bellows1 slide holder1 ground-glass observation plate1 and eye-piece4 ,in making photographs1 the small end of the bellows is attached to the ocular of the microscope1 the focus adjusted1 and the object or objects photographed4 ,more uniform results are obtained in making such photographs if an artificial light of an unvarying candle-power is used4 ,illustration3 ,,fig4 #bi4--,microphotographic ,apparatus ,there are obtainable more elaborate microphotographic apparatus than the one figured and described1 but for most workers this one will prove highly satisfactory4 ,it is possible1 by inclining the tube of the microscope1 to make good microphotographs with an ordinary plate camera4 ,this is accomplished by removing the lens of the camera and attaching the bellows to the ocular1 focusing1 and photographing4 ,,chapter ,,iv ,,how ,,to ,,use ,,the ,,microscope ,in beginning work with the compound microscope1 place the base of the microscope opposite your right shoulder1 if you are right-handed2 or opposite your left shoulder1 if you are left-handed4 ,incline the body so that the ocular is on a level with your eye1 if necessary2 but if not1 work with the body of the microscope in an erect position4 ,in viewing the specimen1 keep both eyes open4 ,use one eye for observation and the other for sketching4 ,in this way it will not be necessary to remove the observation eye from the ocular unless it be to complete the details of a sketch4 ,learn to use both eyes4 ,most workers1 however1 accustom themselves to using one eye2 when they are sketching1 they use both eyes1 although it is not necessary to do so4 ,open the iris diaphragm1 and incline the mirror so that white light is reflected on the ,abb condenser4 ,place the slide on the centre of the stage1 and if the slide contains a section of a plant1 move the slide so as to place this specimen over the centre of the ,abb condenser4 ,then lower the body by means of the coarse adjustment until the low-power object1 which should always be in position when work is begun1 is within one-fourth of an inch of the stage4 ,then raise the body by means of the coarse adjustment until the object1 or objects1 in case a powder is being examined1 is seen4 ,open and close the iris diaphragm1 finally adjusting the opening so that the best possible illumination is obtained for bringing out clearly the structure of the object or objects viewed4 ,then regulate the focus by moving the body up or down by turning the fine adjustment4 ,when studying cross-sections or large particles of powders1 it is sometimes desirable to make low-power sketches of the specimen4 ,in most cases1 however1 only sufficient time should be spent in studying the specimen to give an idea of the size1 structure1 and general arrangement or plan or structure if a section of a plant1 or1 if a powder1 to note its striking characters4 ,all the finer details of structure are best brought out with the high-power objective in position4 ,in placing the high-power objective in position1 it is first necessary to raise the body by the coarse adjustment2 then open the iris diaphragm1 and lower the body until the objective is within about one-eighth of an inch of the slide4 ,now raise the tube by the fine adjustment until the object is in focus1 then gradually close the iris diaphragm until a clear definition of the object is obtained4 ,now proceed to make an accurate sketch of the object or objects being studied4 ,in using the water or oil-immersion objectives it is first necessary to place a drop of distilled water or oil1 as the case may be1 immediately over the specimen1 then lower the body by the coarse adjustment until the lens of the objective touches the water or the oil4 ,raise the tube1 regulate the light by the iris diaphragm1 and proceed as if the high-power objectives were in position4 ,the water or oil should be removed from the objectives and from the slide when not in use4 ,after the higher-powered objective has been used1 the body should be raised1 and the low-power objective placed in position4 ,if the draw-tube has been drawn out during the examination of the object1 replace it1 but be sure to hold one hand on the nose-piece so as to prevent scratching the objective and ,abb condenser by their coming in forceful contact4 ,lastly1 clean the mirror with a soft piece of linen4 ,in returning the microscope to its case1 or to the shelf1 grasp the limb1 or the pillar1 firmly and carry as nearly vertical as possible in order not to dislodge the eye-piece4 ,,illumination ,the illumination for microscopic work may be from natural or artificial sources4 ,illustration3 ,,fig4 #cj4--,micro ,lamp ,it has been generally supposed that the best possible illumination for microscopic work is diffused sunlight obtained from a northern direction4 ,no matter from what direction diffused sunlight is obtained1 it will be found suitable for microscopic work4 ,in no case should direct sunlight be used1 because it will be found blinding in its effects upon the eyes4 ,natural illumination--diffused sunlight--varies so greatly during the different months of the year1 and even during different periods of the day1 that individual workers are resorting more and more to artificial illumination4 ,the particular advantage of such illumination is due to the fact that its quality and intensity are uniform at all times4 ,there are many ways of securing such artificial illumination1 no one of which has any particular advantage over the other4 ,some workers use an ordinary gas or electric light with a color screen placed in the sub-stage below the iris diaphragm4 ,in other cases a globe filled with a weak solution of copper sulphate is placed in such a way between the source of light and the microscope that the light is focused on the mirror4 ,modern mechanical ingenuity has devised1 however1 a number of more convenient micro lamps 7,fig4 #cj74 ,these lamps are a combination of light and screen4 ,in some forms a number of different screens come with each lamp1 so that it is possible to obtain white-1 blue-1 or dark-ground illumination4 ,the type of the screen used will be varied according to the nature of the object studied4 ,,care ,,of ,,the ,,microscope ,if possible1 the microscope should be stored in a room of the same temperature as that in which it is to be used4 ,in any case1 avoid storing in a room that is cooler than the place of use1 because when it is brought into a warmer room1 moisture will condense on the ocular objectives and mirrors4 ,before beginning work remove all moisture1 dust1 etc41 from the inner and outer lenses of the ocular1 the objectives1 the ,abb condenser1 and the mirror by means of a piece of soft1 old linen4 ,when the work is finished the optical parts should be thoroughly cleaned4 ,if reagents have been used1 be sure that none has got on the objectives or the ,abb condenser4 ,if any reagent has got on these parts1 wash it off with water1 and then dry them thoroughly with soft linen4 ,the inner lenses of the eye-pieces and the under lens of the ,abb condenser should occasionally be cleaned4 ,the mechanical parts of the stand should be cleaned if dust accumulates1 and the movable surfaces should be oiled occasionally4 ,never attempt to make new combinations of the ocular or objective lenses1 or transfer the objectives or ocular from one microscope to another1 because the lenses of any given microscope form a perfect lens system1 and this would not be the case if they were transferred4 ,keep clean cloths in a dust-proof box4 ,under no circumstances touch any of the optical parts with your fingers4 ,,preparation ,,of ,,specimens ,,for ,,cutting ,most drug plants are supplied to pharmacists in a dried condition4 ,it is necessary1 therefore1 to boil the drug in water1 the time varying from a few minutes1 in the case of thin leaves and herbs1 up to a half hour if the drug is a thick root or woody stem4 ,if a green 7undried7 drug is under examination1 this first step is not necessary4 ,if the specimen to be cut is a leaf1 a flower-petal1 or other thin1 flexible part of a plant1 it may be placed between pieces of elder pith or slices of carrot or potato before cutting4 ,,short ,,paraffin ,,process ,in most cases1 however1 more perfect sections will be obtained if the specimens are embedded in paraffin1 by the quick paraffin process1 which is easily carried out4 ,after boiling the specimen in water1 remove the excess of moisture from the outer surface with filter paper or wait until the water has evaporated4 ,next make a mould of stiff cardboard and pour melted paraffin 7melting at #ej or #fj degrees7 into the mould to a height of about one-half inch1 when the paraffin has solidified4 ,this may be hastened by floating it on cool or iced water instead of allowing it to cool at room temperature4 ,the specimens to be cut are now placed on the paraffin1 with glue1 if necessary1 to hold them in position1 and melted paraffin poured over the specimens until they are covered to a depth of about one-fourth of an inch4 ,cool on iced water1 trim off the outer paraffin to the desired depth1 and the ,specimen will be in a condition suitable for cutting4 ,good workable sections may be cut from specimens embedded by this quick paraffin method4 ,after a little practice the entire process can be carried out in less than an hour4 ,this method of preparing specimens for cutting will meet every need of the pharmacognosist4 ,,long ,,paraffin ,,process ,in order to bring out the structure of the protoplast 7living part of the cell71 it will be necessary to begin with the living part of the plant and to use the long paraffin method or the collodion method4 ,small fragments of a leaf1 stem1 or root-tip are placed in chromic-acid solution1 acetic alcohol1 picric acid1 chromacetic acid1 alcohol1 etc41 depending upon the nature of the specimen under observation4 ,the object of placing the living specimen in such solutions is to kill the protoplast suddenly so that the parts of the cell will bear the same relationship to each other that they did in the living plant1 and to fix the parts so killed4 ,after the fixing process is complete1 the specimen is freed of the fixing agent by washing in water4 ,from the water-bath the specimens are transferred successively to #aj1 #bj1 #dj1 #fj1 #gj1 #hj1 #ij1 and finally #ajj per cent alcohol4 ,in this #ajj per cent alcohol-bath the last traces of moisture are removed4 ,the length of time required to leave the specimens in the different percentages of alcohols varies from a few minutes to twenty-four hours1 depending upon the size and the nature of the specimen4 ,illustration3 ,,fig4 #ca4--,paraffin-embedding ,oven ,after dehydration the specimen is placed in a clearing agent--chloroform or xylol--both of which are suitable when embedding in paraffin4 ,the clearing agents replace the alcohol in the cells1 and at the same time render the tissues transparent4 ,from the clearing agent the specimen is placed in a weak solution of paraffin1 dissolved xylol1 or chloroform4 ,the strength of the paraffin solution is gradually increased until it consists of pure paraffin4 ,the temperature of the paraffin-embedding oven 7,fig4 #ca7 should not be much higher than the melting-point of the paraffin4 ,the specimen is now ready to be embedded4 ,first make a mould of cardboard or a lead-embedding frame 7,fig4 #cb71 melt the paraffin1 and then place the specimen in a manner that will facilitate cutting4 ,remove the excess of paraffin and cut when desired4 ,illustration3 ,,fig4 #cb4--,paraffin ,blocks ,in using the collodion method for embedding fibrous specimens1 as wood1 bark1 roots1 etc41 the specimen is first fixed with picric acid1 washed with water1 cleared in ether-alcohol1 embedded successively in two1 five1 and twelve per cent ether-alcohol collodion solution1 and finally embedded in a pure collodion bath4 ,,cutting ,,sections ,specimens prepared as described above may be cut with a hand microtome or a machine microtome4 ,,hand ,,microtome ,in cutting sections by a hand microtome1 it is necessary to place the specimen1 embedded in paraffin or held between pieces of elder pith1 carrot1 or potato1 over the second joints of the fingers1 then press the first joints firmly upon the specimen with the thumb pressed against it4 ,if they are correctly held1 the specimens will be just above the level of the finger and the end of the thumb1 and the joint will be below the level of the finger4 ,illustration3 ,,fig4 #cc4--;,hand ,microtome ,hold the section cutter 7,fig4 #cc7 firmly in the hand with the flat surface next to the specimen4 ,while cutting the section1 press your arm firmly against your chest1 and bend the wrist nearly at right angles to the arm4 ,push the cutting edge of the microtome toward the body and through the specimen in such a way as to secure as thin a section as possible4 ,do not expect to obtain nice1 thin sections during the first or second trials1 but continued practice will enable one to become quite efficient in cutting sections in this manner4 ,when the examination of drugs is a daily occurrence1 the above method will be found highly satisfactory4 ,,machine ,,microtomes ,when a number of sections are to be prepared from a given specimen1 it is desirable to cut the sections on a machine microtome1 particularly when the sections are to be prepared for the use of students1 in which case they should be as uniform as possible4 ,great care should be exercised in cutting sections with a machine microtome--first1 in the selection of the type of the microtome2 and secondly1 in the style of knife used in cutting4 ,for soft tissues embedded in paraffin or collodion1 the rotary microtome with vertical knife will give best results4 ,the thickness of the specimen is regulated by mechanical means1 so that in cutting the sections it is only necessary to turn a crank and remove the specimens from the knife-edge1 unless there is a ribbon-carrier attachment4 ,if the sections are being cut from a specimen embedded by the quick paraffin method1 it is best to drop the section in a metal cup partly filled with warm water4 ,this will cause the paraffin to straighten out1 and the specimen will uncoil4 ,after sufficient specimens have been cut1 the cup should be placed in a boiling-water bath until the paraffin surrounding the sections melts and floats on the water4 ,before removing the specimen from the water-bath1 it is advisable to shake the glass vigorously in order to cause as many specimens as possible to settle to the bottom of the cup4 ,the cup is then placed in iced water or set aside until the paraffin has solidified4 ,the cake-like mass is then removed from the cup1 and the sections adhering to its under surface are removed by lifting them carefully off with the flat side of the knife and transferring them1 together with the sections at the bottom of the cup1 to a wide-mouth bottle1 and covered with alcohol1 glycerine1 and water mixture2 or if it is desired to stain the specimens1 they should be placed in a weak alcoholic solution4 ,specimens having a hard1 woody texture should be cut on a sliding microtome by means of a special wood knife1 which is especially tempered to cut woody substances4 ,woody roots1 wood1 or thick bark may be cut readily on this microtome when they have been embedded by the quick paraffin process4 ,the knife in the sliding microtome is placed in a horizontal position1 slanting so that the knife-edge is drawn gradually across the specimen4 ,after cutting1 the sections are treated as described above4 ,the thickness of the sections is regulated by mechanical means4 ,after a section has been cut1 the block containing the specimen is raised by turning a thumb-screw4 ,in this microtome the knife1 as in the rotary type1 is fixed1 and the block containing the specimen is movable4 ,if the specimen has been infiltrated with1 and embedded in1 paraffin or collodion1 the treatment of the sections after cutting should be different4 ,in the case of paraffin1 the sections are fastened directly to the slide1 and the paraffin is dissolved by either chloroform or xylol4 ,the specimen is then placed in #ajj1 #ie1 and #de per cent alcohol1 and then washed in water4 ,these sections are now stained with water-stains1 brought back through alcohol1 cleared1 and mounted in ,canada balsam4 ,if alcoholic stains are used1 it will not be necessary to dehydrate before staining1 and the dehydration after staining will also be eliminated4 ,sections infiltrated with collodion are either stained directly without removing the collodion or after removal4 ,,forms ,,of ,,microtomes ,the hand cylinder microtome 7,fig4 #cd7 consists of a cylindrical body4 ,the clamp for holding the specimen is near the top below the cutting surface4 ,at the lower end is attached a micrometer screw with a divided milled head4 ,when moved forward one division1 the specimen is raised #j4ja mm4 ,this micrometer screw has an upward movement of #aj mm4 ,the cutting surface consists of a cylindrical glass ring4 ,illustration3 ,,fig4 #cd4--;,hand ,cylinder ,microtome ,illustration3 ,,fig4 #ce4--;,hand ,table ,microtome ,the hand table microtome 7,fig4 #ce7 is provided with a clamp1 by which it may be attached to the edge of a table or desk4 ,the cutting surface consists of two separated but parallel glass benches4 ,the object is held by a clamp and is raised by a micrometer screw1 which1 when moved through one division by turning the divided head1 raises the specimen #j4ja mm4 ,the sliding microtome has a track of #bej mm4 ,the object is held by a clamp and its height regulated by hand4 ,the disk regulating the micrometer screw is divided into one hundred parts4 ,when this is turned through one division1 the object is raised #j4jje mm4 or #e microns1 at the same time a clock-spring in contact with teeth registers by a clicking sound4 ,if the disk is turned through two divisions1 there will be two clicks1 etc4 ,in this way is regulated the thickness of the sections cut4 ,when the micrometer screw has been turned through the one hundred divisions1 it must be unscrewed1 the specimen raised1 and the steps of the process repeated4 ,the knife is movable and is drawn across the specimen in making sections4 ,illustration3 ,,fig4 #cf4--;,base ,sledge ,microtome ,the base sledge microtome 7,fig4 #cf7 has a heavy iron base which supports a sliding-way on which the object-carrier moves4 ,the object-carrier is mounted on a solid mass of metal1 and is provided with a clamp for holding the object4 ,the object is raised by turning a knob which1 when turned once1 raises the specimen one to twenty microns1 according to how the feeding mechanism is set4 ,sections thicker than twenty microns may be obtained by turning the knob two or more times4 ,the knife is fixed and is supported by two pillars1 the base of which may be moved forward or backward in such a manner that the knife can be arranged with an oblique or right-angled cutting surface4 ,illustration3 ,,fig4 #cg4--,minot ,rotary ,microtome ,the ,minot rotary microtome 7,fig4 #cg7 has a fixed knife1 held in position by two pillars1 and a movable object-carrier4 ,the object is firmly secured by a clamp1 and it is raised by a micrometer screw4 ,the screw is attached to a wheel having five hundred teeth on its periphery4 ,a pawl is adjusted to the teeth in such a way that1 when moved by turning a wheel to which it is attached1 specimens varying from one to twenty-five microns in thickness may be cut1 according to the way the adjusting disk is set4 ,when the mechanism has been regulated and the object adjusted for cutting1 it is only necessary to turn a crank in cutting sections4 ,,care ,,of ,,microtomes ,when not in use1 microtomes should be protected from dust1 and all parts liable to friction should be oiled4 ,microtome knives should be honed as often as is necessary to insure a proper cutting edge4 ,after cutting objects1 the knives should be removed1 cleaned1 and oiled4 ,it should be kept clearly in mind that special knives are required for cutting collodion1 paraffin1 and frozen and woody sections4 ,the cutting edges of the different knives vary considerably1 as is shown in the preceding cuts4 ,,chapter ,v ,,reagents ,little attention is given in the present work to micro-chemical reactions for the reason that their value has been much overrated in the past4 ,a few reagents will be found useful1 however1 and these few are given1 as well as their special use4 ,they are as follows3 ,,list ,,of ,,reagents ,distilled ,water is used in the alcohol1 glycerine1 and water mixture as a general mounting medium4 ,it is used when warm as a test for inulin and it is used in preparing various reagents4 ,glycerine is used in preparing the alcohol1 glycerine1 and water mixture1 in testing for aleurone grains1 and as a temporary mounting medium4 ,alcohol is used in preparing the alcohol1 glycerine1 and water mixture1 in testing for volatile oils4 ,acetic ,acid4 ,both dilute and strong solutions are used in testing for aleurone grains1 cystoliths1 and crystals of calcium oxalate4 ,hydrochloric ,acid is used in connection with phloroglucin as a test for lignin and as a test for calcium oxalate4 ,ferric ,chloride ,solution is used as a test for tannin4 ,sulphuric ,acid is used as a test for calcium oxalate4 ,tincture ,alkana is used when freshly prepared by macerating the granulated root with alcohol and filtering1 as a test for resin4 ,sodium ,hydroxide4 ,a five per cent solution is used as a test for suberin and as a clearing agent4 ,copper ,ammonia is used as a test for cellulose4 ,ammonical ,solution of ,potash is used as a test for fixed oils4 ,the solution is a mixture of equal parts of a saturated solution of potassium hydroxide and stronger ammonia4 ,oil of ,cloves is used as a clearing fluid for sections preparatory to mounting in ,canada balsam4 ,canada ,balsam is used as a permanent mounting medium for dehydrated specimens1 and as a cement for ringing slides4 ,paraffin is used for general embedding and infiltrating4 ,lugol's ,solution is used as a test for starch and for aleurone grains and proteid matters4 ,osmic ,acid4 ,a two per cent solution is used as a test for fixed oils4 ,alcohol1 ,glycerine1 and ,water ,mixture is used as a temporary mounting medium and as a qualitative test for fixed oils4 ,chlorzinc ,iodide is used as a test for suberin1 lignin1 cellulose1 and starch4 ,analine ,chloride is used as a test for lignified cell walls of bast fibres and of stone cells4 ,phloroglucin4 ,a one per cent alcoholic solution is used in connection with hydrochloric acid as a test for lignin4 ,hmatoxylin-,delifields is used as a test for cellulose4 ,illustration3 ,,fig4 #ch4--,reagent ,set ,,reagent ,,set ,each worker should be provided with a set of reagent bottles 7,fig4 #ch74 ,such a set may be selected according to the taste of the individual1 but experience has shown that a #cj c4c4 bottle with a ground-in pipette and a rubber bulb is preferable to other types4 ,in such forms the pipettes are readily cleaned1 and the rubber bulbs can be replaced when they become old and brittle4 ,the entire set should be protected from dust by keeping it in a case1 the cover of which should be closed when the set is not in use4 ,,measuring ,,cylinder ,in order accurately to measure micro-chemical reagents1 it is necessary to have a standard #ej c4c4 cylinder 7,fig4 #ci7 graduated to c4c4's4 ,such a cylinder should form a part of the reagent set4 ,illustration3 ,,fig4 #ci4--,measuring ,cylinder ,,staining ,,dishes ,illustration3 ,,fig4 #dj4--,staining ,dish ,there is a great variety of staining dishes 7,fig4 #dj71 but for general histological work a glass staining dish with groves for holding six or more slides and a glass cover is most desirable4 ,,chapter ,,vi ,,how ,,to ,,mount ,,specimens ,the method of procedure in mounting specimens for study varies according to the nature of the specimen1 its preliminary treatment1 and the character of the mount to be made4 ,as to duration1 mounts are either temporary or permanent4 ,,temporary ,,mounts ,in preparing a temporary mount1 place the specimen in the centre of a clean slide and add two or more drops of the temporary mounting medium1 which may be water1 or a mixture of equal parts of alcohol1 glycerine1 and water1 or some micro-chemical reagent1 as weak ,lugol's solution1 solution of chloral hydrate1 etc4 ,cover this with a cover glass and press down gently4 ,remove the excess of the mounting medium with a piece of blotting paper4 ,now place the slide on the stage and proceed to examine it4 ,such mounts can of course be used only for short periods of study2 and when the period of observation is finished1 the specimen should be removed and the slide washed1 or the slide washing may be deferred until a number of such slides have accumulated4 ,at any rate1 when the mounting medium dries1 the specimen is no longer suitable for observation4 ,,permanent ,,mounts ,permanent mounts are prepared in much the same way as temporary1 but of course the mounting medium is different4 ,the kind of permanent mounting medium used depends upon the previous treatment of the specimen4 ,if the specimen has been preserved in alcohol or glycerine and water1 it is usually mounted in glycerine jelly4 ,if the specimen in question is a powder1 it is placed in the centre of the slide and a drop or two of glycerine1 alcohol1 and water mixture added1 unless the powder was already in suspension in such a mixture4 ,cut a small cube of glycerine jelly and place it in the centre of the powder mixture4 ,lift up the slide by means of pliers1 or grasp the two edges between the thumb and finger and hold over a small flame of an alcohol lamp1 or place on a steam-bath until the glycerine jelly has melted4 ,next sterilize a dissecting needle1 cool1 and mix the powder with the glycerine jelly1 being careful not to lift the point of the needle from the slide during the operation4 ,if the mixing has been carefully done1 few or no air-bubbles will be present2 but if they are present1 heat the needle1 and while it is white hot touch the bubbles with its point1 and they will disappear4 ,now take a pair of forceps and1 after securing a clean cover glass near the edge1 pass them three times through the flame of the alcohol lamp4 ,while holding it in a slanting position1 touch one side of the powder mixture and slowly lower the cover glass until it comes in complete contact with the mixture4 ,now press gently with the end of the needle-handle1 and set it aside to cool4 ,when it is cool1 place a neatly trimmed label on one end of the slide1 on which write the name of the specimen1 the number of the series of which it is to form a part1 etc4 ,any excess of glycerine jelly1 which may have been pressed out from the edges of the cover glass1 should not be removed at once1 but should be allowed to remain on the slide for at least one month in order to allow for shrinkage due to evaporation4 ,at the end of a month remove the glycerine jelly by first passing the blade of a knife1 held in a vertical position1 the back of the knife being next to the slide1 around the edge of the cover glass4 ,after turning the knife-blade so that the flat side is in contact with slide1 remove the jelly outside of the cover glass4 ,any remaining fragments should be removed with a piece of old linen or cotton cloth4 ,finally1 ring the edge of the cover glass with microscopical cement1 of which there are many types to be had4 ,if the cleaning has been done thoroughly1 there is no better ringing cement than ,canada balsam4 ,in mounting cross-sections1 the method of procedure is similar to the above1 with the exception that the glycerine jelly is placed at the side of the specimen and not in the centre4 ,while melting the jelly1 incline the slide in order to allow the melted glycerine jelly to flow gradually over the specimen1 thus replacing the air contained in the cells and intercellular spaces4 ,finish the mounting as directed above1 but under no conditions should you stir the glycerine jelly with the section4 ,if specimens1 after having been embedded in paraffin or collodion1 are cut1 cleared1 stained1 and dehydrated1 they are usually mounted in ,canada balsam4 ,a small drop of this substance1 which may be obtained in collapsible tubes1 is placed at one side of the specimen4 ,while inclining the slide1 gently heat until the ,canada balsam covers the specimen4 ,secure a cover glass by the aid of pliers1 pass it through the flame three times1 and lower it slowly while holding it in an inclined position4 ,press gently on the cover glass with the needle-handle1 and keep in a horizontal position for twenty-four hours1 then place directly in a slide box or cabinet1 since no sealing is required4 ,glycerine is sometimes used to make permanent mounts1 but it is unsatisfactory1 because the cover glass is easily removed and the specimen spoiled or lost1 unless ringed--a procedure which is not easily accomplished4 ,if the specimen is to be mounted in glycerine1 it must first be placed in a mixture of alcohol1 glycerine1 and water1 and then transferred to glycerine4 ,lactic acid is another permanent liquid-mounting medium1 which is unsatisfactory in the same way as glycerine1 but like glycerine1 there are certain special cases where it is desirable to use it4 ,when this is used1 the slides should be kept in a horizontal position1 unless ringed4 ,,cover ,,glasses ,great care should be used ,in the selection of cover glasses1 however1 not only as regards their shape but as to their thickness4 ,the standard tube length of the different manufacturers makes an allowance of a definite thickness for cover glasses4 ,it is necessary1 therefore1 to use cover glasses made by the manufacturer of the microscope in use4 ,cover glasses are either square or round4 ,of each there are four different thicknesses and two different sizes4 ,the standard thicknesses are3 ,the small size is designated three-fourths and the large size seven-eighths4 ,illustration3 ,,fig4 #da4--,round ,cover ,glass ,illustration3 ,,fig4 #db4--,square ,cover ,glass ,illustration3 ,,fig4 #dc4--,rectangular ,cover ,glass ,cover glasses are circular 7,fig4 #da71 square 7,fig4 #db71 or rectangular 7,fig4 #dc7 pieces of transparent glass used in covering the specimens mounted on glass slides4 ,a few years ago much difficulty was experienced in obtaining uniformly thick and transparent cover glasses1 but no such difficulty is experienced to-day4 ,the type of cover glass used depends largely upon the character of the specimen to be mounted4 ,the square and rectangular glasses are selected when a series of specimens are to be mounted1 but in mounting powdered drugs and histological specimens the round cover glasses are preferable because they are more sightly and more readily cleaned and rinsed4 ,,glass ,,slides ,illustration3 ,,fig4 #dd4--;,glass ,slide ,glass slides 7,fig4 #dd7 are rectangular pieces of transparent glass used as a mounting surface for microscopic objects4 ,the slides are usually three inches long by one inch wide1 and they should be composed of white glass1 and they should have ground and beveled edges4 ,slides should be of uniform thickness1 and they should not become cloudy upon standing4 ,,slide ,,and ,,cover-,,glass ,,forceps ,slides and cover glasses should be grasped by their edges4 ,to the beginner this is not easy4 ,in order to facilitate holding slides and cover glasses during the mounting process1 one may use a slide and a cover-glass forceps4 ,the slide forceps consists of wire bent and twisted in such a way that it holds a slide firmly when attached to its two edges4 ,illustration3 ,,fig4 #de4--;,histological ,forceps ,illustration3 ,,fig4 #df4--;,forceps ,illustration3 ,,fig4 #dg4--,sliding-pin ,forceps ,there are various forms of cover-glass holders1 but only two types as far as the method of securing the cover glass is concerned4 ,first1 there are the bacteriological and the histological forceps 7,fig4 #de71 which are self-closing4 ,the two blades of such forceps must be forced apart by pressure in securing the cover glass4 ,the second type of forceps is that in which the two blades are normally separated 7,fig4 #df71 it being necessary to press the blades to either side of the cover glass in order to secure and hold it4 ,there is a modification of this type of forceps which enables one to lock the blades by means of a sliding pin 7,fig4 #dg71 after the cover glass has been secured4 ,it is well to accustom oneself to one type1 for by so doing one may become dexterous in its use4 ,,needles ,illustration3 ,,fig4 #dh4--;,dissecting ,needle ,two dissecting needles 7,fig4 #dh7 should form a part of the histologist's mounting set4 ,the handles may be of any material1 but the needle should be of tempered steel and about two inches long4 ,,scissors ,illustration3 ,,fig4 #di4--,scissors ,almost any sort of scissors 7,fig4 #di7 will do for histology work1 but a small scissors with fine pointed blades1 are preferred4 ,scissors are useful in trimming labels and in cutting strips of leaves and sections of fibrous roots that are to be embedded and cut4 ,,scalpels ,illustration3 ,,fig4 #ej4--,scalpels ,scalpels 7,fig4 #ej7 have steel blades and ebony handles4 ,these vary in regard to size and quality of material4 ,the cheaper grades are quite as satisfactory1 however1 as the more expensive ones1 and for general use a medium-sized blade and handle will be found most useful4 ,,turntable ,illustration3 ,,fig4 #ea4--,turntable ,much time and energy may be saved by ringing slides on a turntable 7,fig4 #ea74 ,there is a flat surface upon which to rest the hand holding the brush with cement1 and a revolving table upon which the slide to be ringed is held by means of two clips4 ,in ringing slides1 it is only necessary to revolve the table1 and at the same time to transfer the cement to the edge of the cover glass from the brush held in the hand4 ,,labeling ,there are many ways of labeling slides1 but the best method is to place on the label the name of the specimen1 the powder number1 and the box1 the tray or cabinet number4 ,for example3 ,powdered ,arnica ,flowers ,no4 #hj--;,box ,a--#fjj4 ,,preservation ,,of ,,mounted ,,specimens ,illustration3 ,,fig4 #eb4--,slide ,box ,illustration3 ,,fig4 #ec4--,slide ,tray ,accurately mounted1 labeled1 and ringed slides should be filed away for future study and reference4 ,such filing may be done in slide boxes1 in slide trays1 or in cabinets4 ,slide boxes are to be had of a holding capacity varying from one to one hundred slides4 ,for general use1 slide boxes 7,fig4 #eb7 holding one hundred slides will be found most useful4 ,some workers prefer trays 7,fig4 #ec71 because of the saving of time in selecting specimens4 ,trays hold twenty slides arranged in two rows4 ,the cover of the tray is divided into two sections so that1 if desired1 only one row of slides is uncovered at a time4 ,slide cabinets 7,fig4 #ed7 are particularly desirable for storing large individual collections1 particularly when the slides are used frequently for reference4 ,large selections of slides should be numbered and card indexed in order to facilitate finding4 ,illustration3 ,,fig4 #ed4--,slide ,cabinet ,part ,,ii ,,tissues ,,cells1 ,,and ,,cell ,,contents ,,chapter ,i ,,the ,,cell ,the cell is the unit of structure of all plants4 ,in fact the cell is the plant in many of the lower forms--so called unicellular plants4 ,all plants1 then1 consist of one or more cells4 ,while cells vary greatly in size1 form1 color1 contents1 and function1 still in certain respects their structure is identical4 ,,typical ,,cell ,the typical vegetable cell is composed of a living portion or protoplast and an external covering1 or wall4 ,the protoplast includes everything within the wall4 ,it is made up of a number of parts1 each part performing certain functions yet harmonizing with the work of the cell as a whole4 ,the protoplast 7protoplasm7 is a viscid substance resembling the white of an egg4 ,the protoplast1 when unstained and unmagnified1 appears structureless1 but when stained with dyes and magnified1 it is found to be highly organized4 ,the two most striking parts of the protoplast are the cytoplasm and the nucleus4 ,the part of the protoplast lining the innermost part of the wall is the ectoplast1 which is less granular and slightly denser than most of the cytoplasm4 ,the cytoplasm is decidedly granular in structure4 ,in the cytoplasm occurs one or more cavities1 vacuoles1 filled with cell sap4 ,embedded in the cytoplasm are numerous chromatophores1 which vary in color in the different cells1 from colorless to yellow1 to red1 and to green4 ,the nucleus is the seat of the vital activity of the cell1 and the seat of heredity4 ,the whole life and activity of the cell centre1 therefore1 in and about the nucleus4 ,the outer portion of the nucleus consists of a thin membrane or wall4 ,the membrane encloses numerous granular particles--chromatin--which are highly susceptible to organic stains4 ,among the granules are thread-like particles or linin4 ,near the centre of the nucleus are one or more small rounded nucleoli4 ,the liquid portion of the nucleus1 filling the membranes and surrounding the chromatin1 linin1 and nucleoli1 is the nuclear sap4 ,other cell contents characteristic of certain cells are crystals1 starch1 aleurone1 oil1 and alkaloids4 ,the detailed discussion of these substances will be deferred until a later chapter4 ,the cell wall which surrounds the protoplast is a product of its activity4 ,the structure and composition of the wall of any given cell vary according to the ultimate function of the cell4 ,the walls may be thin or thick1 porous or non-porous1 and colored or colorless4 ,the composition of cell walls varies greatly4 ,the majority of cell walls are composed of cellulose1 in other cells of linin1 in others of cutin1 and in still others of suberin1 etc4 ,in the majority of cells the walls are laid down in a series of layers one over the other by apposition1 similar to the manner of building a pile of paper from separate sheets4 ,the first layer is deposited over the primary wall1 formed during cell division2 to this is added another layer1 etc4 ,a modification of this manner of growth is that in which the layers are built up one over the other1 but the building is gradually done by the deposit of minute particles of cell-wall substance over the older deposits4 ,such walls are never striated1 as is likely to be the case in cell walls formed by the first method4 ,in other cells the walls are increased in thickness by the deposition of new wall material in the older membrane4 ,the cell walls will be discussed more fully when the different tissues are studied in detail4 ,,indirect ,,cell ,,division 7,,karyokinesis7 ,the purpose of cell division is to increase the number of cells of a tissue1 an organ1 an organism1 or to increase the number of organisms1 etc4 ,such cell divisions involve1 first1 an equal division of the protoplast and1 secondly1 the formation of a wall between the divided protoplasts4 ,the first changes in structure of a cell undergoing division occur in the nucleus4 ,,changes ,,in ,a ,,cell ,,undergoing ,,division ,the linin threads become thicker and shorter4 ,the chromatin granules increase in size and amount2 the threads and chromatin granules separate into a definite number of segments or chromosomes 7,plate #a1 ,fig4 #b74 ,the nuclear membrane becomes invested with a fibrous protoplasmic layer which later separates and passes into either end of the cell1 there forming the polar caps 7,plate #a1 ,fig4 #c74 ,the nuclear membrane and the nucleoli disappear at about this time4 ,two fibres1 one from each polar cap1 become attached to opposite sides of the individual chromosomes4 ,other fibres from the two polar caps unite to form the spindle fibres1 which thus extend from pole to pole4 ,all these spindle fibres form the nuclear spindle 7,plate #a1 ,fig4 #e74 ,the chromosomes now pass toward the division centre of the cell or equatorial plane and form1 collectively1 the equatorial plate 7,plate #a1 ,fig4 #e74 ,at this point of cell division1 the chromosomes are ,u-shaped1 and the curved part of the chromosomes faces the equatorial plane4 ,the chromosomes finally split into two equal parts 7,plate #a1 ,fig4 #f74 ,the actual separation of the halves of chromosomes is brought about by the attached polar fibres1 which contract toward the polar caps 7,plate #a1 ,fig4 #g74 ,the chromosomes are finally drawn to the polar caps 7,plate #a1 ,fig4 #h74 ,the chromosomes now form a rounded mass4 ,they then separate into linin threads and chromatin granules4 ,nucleoli reappear1 and nuclear sap forms4 ,finally1 a nuclear membrane develops4 ,the spindle fibres1 which still extend from pole to pole1 become thickened at the equatorial plane 7,plate #a1 ,fig4 #h71 and finally their edges become united to form the cell-plate 7,plate #a1 ,fig4 #i71 which extends across the cell1 thus completely separating the mother cell into two daughter cells4 ,after the formation of the cell-plate1 the spindle fibres disappear4 ,the cell becomes modified to form the middle lamella1 on either side of which the daughter protoplast adds a cellulose layer4 ,the ultimate composition of the middle lamella and the composition and structure of the cell wall will differ according to the function which the cell will finally perform4 ,illustration3 ,,plate #a ,nine figures1 showing stages in the cell-division common to the onion root 7,allium cepa1 ,l47 ,,origin ,,of ,,multicellular ,,plants ,all multicellular plants are built up by the repeated cell division of one original cell4 ,if the cells formed are similar in structure and function1 they form a tissue4 ,in multicellular plants many different kinds of tissues will be formed as a result of cell division1 since there are many different functions to be performed by such an organism4 ,when several of these tissues become associated and their functions are correlated1 they form an organ4 ,the association of several organs in one form makes an organism4 ,the oak-tree is an organism4 ,it is made up of organs known as flowers1 leaves1 stems1 roots1 etc4 ,each of these organs is in turn made up of several kinds of tissue4 ,in some cases it is difficult to designate a single function to an aggregation of cells 7tissue74 ,in fact1 a tissue may perform different functions at different periods of its existence or it may perform two functions at one and the same time2 as an example1 stone cells1 whose primary function is mechanical1 in many cases function as storage tissue4 ,the cells forming the tissues of the plant1 in fact1 show great adaptability in regard to the function which they perform4 ,nevertheless there is a predominating function which all tissues perform1 and the structure of the cells forming such tissues is so uniform that it is possible to classify them4 ,the functional classification of tissues is chosen for the purpose of demonstrating the adaptation of cell structure to cell function4 ,if the cells performing a similar function in the different plants were identical in number1 distribution1 form1 color1 size1 structure1 and cell contents1 there would not be a science of histology upon which the art of microscopic pharmacognosy is based4 ,it may be said1 however1 with certainty1 that the cells forming certain of the tissues of any given species of plant will differ in a recognizable degree from cells performing a similar function in other species of plants4 ,often a tissue is present in one plant but absent in another4 ,for example1 many aquatic plants are devoid of mechanical fibrous cells4 ,the barks of certain plants have characteristic stone cells1 while in many other barks no stone cells occur4 ,many leaves have characteristic trichomes2 others are free from trichomes1 etc4 ,yet all cells performing a given function will structurally resemble each other4 ,in the present work the nucleus and other parts of the living protoplast will not be considered1 for the reason that these parts are not in a condition suitable for study1 because most drugs come to market in a dried condition1 a condition which eliminates the possibility of studying the protoplast4 ,the general structure of the cells forming the different tissues will first be considered1 then their variation1 as seen in different plants1 and finally their functions4 ,,chapter ,,ii ,,the ,,epidermis ,,and ,,periderm ,the epidermis and its modifications1 the hypodermis and the periderm1 form the dermal or protective outer layer or layers of the plant4 ,the epidermis of most leaves1 stems of herbs1 seeds1 fruits1 floral organs1 and young woody stems consists of a single layer of cells which form an impervious outer covering1 with the exception of the stoma4 ,,leaf ,,epidermis ,the cells of the epidermis vary in size1 in thickness of the side and end walls1 in form1 in arrangement1 in character of outgrowths1 in the nature of the surface deposits1 in the character of wall--whether smooth or rough--and in size4 ,in cross-sections of the leaf the character of both the side and end walls is easily studied4 ,in surface sections--the view most frequently seen in powders--the side walls are more conspicuous than the end wall 7,plates #b and #c74 ,this is so because the light is considerably retarded in passing through the entire length of the side walls1 while the light is retarded only slightly in passing through the end wall4 ,the light in this case passes through the width 7thickness7 of the wall only4 ,the outer walls of epidermal cells are characteristic only when they are striated1 rough1 pitted1 colored1 etc4 ,in the majority of leaves the outer wall of the epidermal cells is not diagnostic in powders1 or in surface sections4 ,the thickness of the end and side walls of epidermal cells differs greatly in different plants4 ,as a rule1 leaves of aquatic and shade-loving plants1 as well as the leaves of most herbs have thinner walled epidermal cells than have the leaves of plants growing in soil under normal conditions1 or than have the leaves of shrubs and trees4 ,illustration3 ,,plate #b ,,leaf ,,epidermis #a4 ,uva-ursi 7,arctostaphylos uva-ursi1 ,l4 ,spring74 #b4 ,boldus 7,peumus boldus1 ,molina74 #c4 ,catnip 7,nepeta cataria1 ,l474 #d4 ,digitalis 7,digitalis purpurea1 ,l474 #d-;,a4 ,origin of hair4 ,illustration3 ,,plate #c ,,leaf ,,epidermis #a4 ,upper striated epidermis of chirata leaf 7,swertia chirata1 ,roxb4 ,ham474 #b4 ,green hellebore leaf 7,veratrum viride1 ,ait474 #c4 ,boldus leaf 7,peumus boldus1 ,molina74 #d4 ,under epidermis of ,india senna 7,cassia angustifolia1 ,vahl474 ,the widest possible range of cell-wall thickness is therefore found in the medicinal leaves1 because the medicinal leaves are collected from aquatic plants1 herbs1 shrubs1 trees1 etc4 ,the outer wall is always thicker than the side walls4 ,even the side walls vary in thickness in some leaves1 the wall next to the epidermis being thicker than the lower or innermost portion of the wall4 ,frequently the outermost part of the side walls is unequally thickened4 ,this is the case in the beaded side walls characteristic of the epidermis of the leaves of laurus1 myrcia1 boldus1 and capsicum seed1 etc4 ,the thickness of the side walls of the epidermal cells of most leaves varies in the different leaves4 ,in most leaves there are five typical forms of arrangement of epidermal cells3 ,first1 those over the veins which are elongated in the direction of the length of the leaf2 and1 secondly1 those on other parts of the leaf which are usually several-sided and not elongated in any one direction4 ,if the epidermis of the leaf has stoma1 then there is a third type of arrangement of the epidermal cells around the stoma2 fourthly1 the cells surrounding the base of hairs2 and fifthly1 outgrowths of the epidermis1 non-glandular and glandular hairs1 etc4 ,it should be borne in mind that in each species of plant the five types of arrangement are characteristic for the species4 ,the character of the outer wall of the epidermal cells differs greatly in different plants4 ,in most cases the wall is smooth2 senna is an example of such leaves4 ,in certain other leaves the wall is rough1 the roughness being in the form of striations4 ,in some cases the striations occur in a regular manner2 belladonna leaf is typical of such leaves4 ,in other instances the wall is striated in an irregular manner as shown in chirata epidermis4 ,very often an epidermis is rough1 but the roughness is not due to striations4 ,in these cases the epidermis is unevenly thickened1 the thin places appearing as slight depressions1 the thick places as slight elevations4 ,boldus has a rough1 but not a striated surface4 ,surface deposits are not of common occurrence in medicinal plants2 waxy deposits occur on the stem of sumac1 on a species of raspberry1 on the fruit of bayberry1 etc4 ,resinous deposits occur on the leaves and stems of grindelia species1 and on yerba santa4 ,in certain leaves there are two or three layers of cells beneath the epidermis that are similar in structure to the epidermal cells4 ,these are called hypodermal cells1 and they function in the same way as the epidermal cells4 ,hypodermal cells are very likely to occur on the margin of the leaf4 ,uva-ursi leaf has a structure typical of leaves with hypodermal marginal cells4 ,uva-ursi1 like other leaves with hypodermal cells has a greater number of hypodermal cells at the leaf margin than at any other part of the leaf surface4 ,the cutinized walls of epidermal cells are stained red with saffranin4 ,,testa ,,epidermis ,testa epidermal cells form the epidermal layers of such seeds as lobelia1 henbane1 capsicum1 paprika1 larkspur1 belladonna1 scopola1 etc4 ,in surface view the end walls are thick and wavy in outline2 frequently the line of union--middle lamella--of two cells is indicated by a dark or light line1 while in others the wall between two cells appears as a single wall4 ,the walls are porous or non-porous1 and the color of the wall varies from yellow to brown1 to colorless4 ,these cells always occur in masses1 composed partially of entire and partially of broken fragments4 ,in lobelia seed 7,plate #d1 ,fig4 #b7 the line of union of adjacent cell walls appears as a dark line4 ,the walls are wavy in outline1 of a yellowish-red color and not porous4 ,in henbane seed 7,plate #d1 ,fig4 #c7 the line of union between the cells is scarcely visible2 the walls are decidedly wavy1 more so than in lobelia1 and no pits are visible4 ,in capsicum seed 7,plate #d1 ,fig4 #a7 the cells are very wavy and decidedly porous1 the line of union between the cell walls being marked with irregular spaces and lines4 ,in belladonna seed 7,plate #e1 ,fig4 #a7 the walls between two adjacent cells are non-striated and non-porous1 and extremely irregular in outline4 ,illustration3 ,,plate #d ,,testa ,,epidermal ,,cells #a4 ,capsicum seed 7,capsicum frutescens1 ,l474 #b4 ,lobelia seed 7,lobelia inflata1 ,l474 #c4 ,henbane seed 7,hyoscyamus niger1 ,l474 ,illustration3 ,,plate #e ,,testa ,,cells #a4 ,belladonna seed 7,atropa belladonna1 ,l474 #b4 ,star-aniseed 7,illicium verum1 ,hooker74 #c4 ,stramonium seed 7,datura stramonium1 ,l474 ,in star-anise seed 7,plate #e1 ,fig4 #b7 the walls are irregularly thickened and wavy in outline4 ,in stramonium seed 7,plate #e1 ,fig4 #c7 the walls are very thick1 wavy in outline1 and striated4 ,,plant ,,hairs 7,,trichomes7 ,in histological work plant hairs are of great importance1 as they offer a ready means of distinguishing and differentiating between plants1 or parts of plants1 when they occur in a broken or finely powdered condition4 ,there is no other element in powdered drugs which is of so great a diagnostic value as the plant hair4 ,the same plant will always have the same type of hair1 the only noticeable variation being in the size4 ,in microscopical drug analysis the presence of hairs is always noted1 and in many cases the purity of the powder can be ascertained from the hairs4 ,botanists seem to have given little attention to the study of plant hairs4 ,this accounts for the fact that information concerning them is very meagre in botanical literature1 and1 as far as the author can learn1 no one has attempted to classify them4 ,in systematic work1 plant hairs could be used to great advantage in separating genera and even species4 ,hairs are1 of course1 a factor now in systematic work4 ,the lack of hairs is indicated by the term glabrous4 ,their presence is indicated by such terms as hispid1 villous1 etc4 ,in certain cases the term indicates position of the hair as ciliate when the hair is marginal4 ,when hairs influence the color of the leaf1 such terms as cinerous and canescent are used4 ,in all the cases cited no mention is made of the real nature of the hair4 ,in systematic work1 as in pharmacognosy1 we must work with dried material1 and it is only those hairs which retain their form under such conditions which are of classification value4 ,hairs are the most common outgrowths of the epidermal cells4 ,they are classified as glandular or non-glandular1 according to their structure and function4 ,the glandular hairs will be considered under synthetic tissue4 ,each group is again subdivided into a number of secondary groups1 depending upon the number of cells present1 their form1 their arrangement1 their size1 their color1 the character of their walls1 whether rough or smooth1 whether branched or non-branched1 whether curved1 twisted1 straight1 or twisted and straight1 whether pointed1 blunt1 or forked4 ,,forms ,,of ,,hairs ,,papill ,papill are epidermal cells which are extended outward in the form of small tubular outgrowths4 ,papill occur on the following parts of the plant3 flower-petals1 stigmas1 styles1 leaves1 stems1 seeds1 and fruits4 ,papill occur on only a few of the medicinal leaves4 ,the under surface of both ,truxillo 7,plate #f1 ,fig4 #c7 and ,huanuca coca have very small papill4 ,the outermost wall of these papill are much thicker than the side walls4 ,the papill of klip buchu 7,plate #f1 ,fig4 #d71 an adulterant of true buchu1 has large thick-walled papill4 ,the velvety appearance of most flower-petals 7,plate #f1 ,figs4 #b and #e7 is due to the presence of papill4 ,the papill of flower-petals are very variable4 ,in calendula flowers 7,plate #f1 ,fig4 #a7 they are small1 yellowish in color1 and the outer wall is marked with parallel striations which appear as small teeth in cross-section4 ,the ray petal papill of anthemis consist of rather large1 broad1 blunt papill with slightly striated walls4 ,the papill of the ray petals of the white daisy consist of papill which have medium sized1 cone-shaped papill with finely striated walls4 ,the papill of the flower stigma vary greatly in different flowers4 ,in some cases two or more types of papill occur1 but even in these cases the papill are characteristic of the species4 ,the papill differ greatly in the case of the flowers of the composit1 where two types of flowers are normally present--namely1 the ray flowers and the disk flowers4 ,in all cases observed the papill of the stigma of the ray flowers are always smaller than the papill of the stigma of the disk flowers4 ,it would appear from extended observation that the papill of the ray flower stigma are being gradually aborted4 ,the papill of the style are always different from the papill of the stigma4 ,the style papill are always smaller1 and they are of a different form4 ,illustration3 ,,plate #f ,,papill #a4 ,calendula flowers 7,calendula officinalis1 ,l474 #b4 ,white daisy ray flower 7,chrysanthemum leucanthemum1 ,l474 #c4 ,coca leaf 7,erythroxylon coca1 ,lamarck74 #d4 ,klip buchu4 #e4 ,anthemis ray petal 7,anthemis nobilis1 ,l474 ,,unicellular ,,non-,,glandular ,,hairs ,true plant hairs are tubular outgrowths of the epidermal cell1 the length of these outgrowths being several times the width of the hair4 ,the unicellular hairs are common to many plants4 ,the two groups of non-glandular unicellular hairs are1 first1 the solitary2 and secondly1 the clustered hairs4 ,solitary unicellular hairs occur on the leaves of chestnut1 yerba santa1 lobelia1 cannabis indica1 the fruit of anise1 and the stem of allspice1 senna1 and cowage4 ,chestnut hairs 7,plate #g1 ,fig4 #a7 have smooth yellowish-colored walls1 and the cell cavity contains reddish-brown tannin4 ,these hairs occur solitary or clustered2 the clustered hairs normally occur on the leaf1 but in powdering the drug1 individual hairs of the cluster become separated or solitary4 ,yerba santa hairs 7,plate #g1 ,fig4 #d7 are twisted1 the lumen or cell cavity is very small1 and the walls1 which are very thick1 are grayish-white4 ,lobelia hairs 7,plate #g1 ,fig4 #e7 are very large4 ,the walls are grayish-white1 and the outer surface extends in the form of small elevations which make the hair very rough4 ,the hair tapers gradually to a solid point4 ,cannabis indica hairs 7,plate #g1 ,fig4 #f7 are curved4 ,the apex tapers to a point and the base is broad1 and it frequently contains deposits of calcium carbonate4 ,the walls are grayish-white in appearance1 and rough4 ,the roughness increases toward the apex4 ,the hairs of anise 7,plate #g1 ,fig4 #g7 are mostly curved2 the walls are thick1 yellowish-white1 and the outer surface is rough2 this is due to the numerous slight centrifugal projections of the outer wall4 ,allspice stem hairs 7,plate #g1 ,fig4 #b7 have smooth walls4 ,the cell cavity is reddish-brown4 ,the hair is curved4 ,the hair of senna 7,plate #g1 ,fig4 #aj7 is light greenish-yellow with rough papillose walls4 ,the hair is usually curved and tapering1 and it does not have any characteristic cell contents4 ,illustration3 ,,plate #g ,,unicellular ,,solitary ,,hairs #a4 ,chestnut leaf 7,castanea dentata1 ,marsh ,borkh74 #b4 ,allspice stems 7,pimento1 officinalis1 ,lindl474 #c4 ,cowage4 #d4 ,yerba santa 7,eriodictyon californicum1 ,h4 and ,a4 ,greene74 #e4 ,lobelia 7,lobelia inflata1 ,l474 #f4 ,cannabis indica 7,cannabis saliva1 ,l474 #g4 ,anise fruit 7,pimpinella anisum1 ,l474 #h4 ,hesperis matronalis 7,hesperis matronalis1 ,l474 #i4 ,galphimia glauca 7,galphimia glauca1 ,cav474 #aj4 ,senna 7,cassia angustifolia1 ,vahl474 ,illustration3 ,,plate #h ,,clustered ,,unicellular ,,hairs #a4 and #b4 ,european oak 7,quercus infectoria1 ,olivier74 #c4 ,kamala 7,mallotus philippinensis1 ,lam4 ,muell4 ,arg474 #d4 ,witch-hazel leaf 7,hamamelis virginiana1 ,l474 #e4 ,althea leaf 7,altha officinalis1 ,l474 ,cowage hairs 7,plate #g1 ,fig4 #c7 are lance-shaped1 and they terminate in a sharp point4 ,the outer wall contains numerous recurved teeth-like projections4 ,the cell cavity is filled with a reddish-brown contents which are somewhat fissured4 ,clustered unicellular hairs occur on the leaves of chestnut1 witch-hazel1 althea1 ,european oak1 etc4 ,in ,european oak 7,plate #h1 ,figs4 #a and #b7 clusters of two and three hairs occur4 ,the walls are yellowish-white1 smooth1 and the tip of the hair is solid4 ,in kamala 7,plate #h1 ,fig4 #c7 clusters of seven or more hairs occur2 the walls are yellowish1 and the cell cavity is reddish-brown4 ,in witch-hazel leaf 7,plate #h1 ,fig4 #d7 clusters of a variable number of hairs occur4 ,the hairs1 which are of various lengths1 have yellowish-white1 thick1 smooth walls1 and reddish cell contents4 ,in althea leaf 7,plate #h1 ,fig4 #e7 the hairs are nearly straight and the walls are smooth4 ,the basal portions of the hair are strongly pitted4 ,branched solitary unicellular hairs occur on the leaves of hesperis matronalis 7,plate #g1 ,fig4 #h71 and on galphimia glauca 7,plate #g1 ,fig4 #i74 ,the hair of hesperis matronalis has smooth walls1 and the two branches grow out nearly parallel to the leaf surface4 ,the hair of galphimia glauca has rough walls1 and the two branches grow upward in a bifurcating manner4 ,,multicellular ,,hairs ,multicellular hairs are divided into the uniseriate and the multiseriate hairs4 ,both of these groups are divided into the branched and the non-branched hairs1 as follows3 #a4 ,uniseriate4 7,a7 ,non-branched4 7,b7 ,branched4 #b4 ,multiseriate4 7,a7 ,non-branched4 7,b7 ,branched4 ,multicellular uniseriate non-branched hairs occur on the leaves of digitalis1 ,western and ,eastern skullcap1 peppermint1 thyme1 yarrow1 arnica flowers1 and sumac fruit4 ,illustration3 ,,plate #i ,,multicellular ,,uniseriate ,,non-,,branched ,,hairs #a4 ,digitalis leaf 7,digitalis purpurea1 ,l474 #b4 ,arnica flower 7,arnica montana1 ,l474 #c4 ,western skullcap plant 7,scutellaria canescens1 ,nutt474 #d4 ,eastern skullcap plant 7,scutellaria lateriflora1 ,l474 #e4 ,peppermint leaf 7,mentha piperita1 ,l474 #f4 ,thyme leaf 7,thymus vulgaris1 ,l474 #g4 ,yarrow flowers 7,achillea millefolium1 ,l474 #h4 ,wormwood leaf 7,artemisia absinthium1 ,l474 #i4 ,sumac fruit 7,rhus glabra1 ,l474 ,digitalis hairs 7,plate #i1 ,fig4 #a7 are made up of a varying number of uniseriate-arranged cells of unequal length1 frequently placed at right angles to the cells above and below2 the walls are of a whitish color1 and are rough or smooth4 ,eastern skullcap 7,plate #i1 ,fig4 #d7 has hairs with not more than four cells2 these hairs are curved1 and the walls are whitish1 sometimes smooth1 but usually rough4 ,in ,western skullcap 7,plate #i1 ,fig4 #c7 the hairs have sometimes as many as seven cells4 ,the walls are white and rough1 and the individual cells of the hair are much larger than are the cells of the hairs of true skullcap4 ,peppermint 7,plate #i1 ,fig4 #e7 has from one to eight cells4 ,the hair is curved1 and the walls are very rough4 ,thyme 7,plate #i1 ,fig4 #f7 has short1 thick1 rough-walled trichomes1 the terminal cell usually being bent at nearly right angles to the other cells4 ,yarrow hairs 7,plate #i1 ,fig4 #g7 have a variable number of cells4 ,in all the hairs the basal cells are short and broad1 while the terminal cell is greatly elongated4 ,arnica hairs 7one form1 ,plate #i1 ,fig4 #b7 have frequently as many as four cells1 the terminal cell being longer than the basal cells4 ,the walls are white and smooth4 ,sumac-fruit hairs 7,plate #i1 ,fig4 #i7 have spindle-shaped1 reddish-colored hairs4 ,multicellular multiseriate non-branched hairs occur on cumin fruit and on the tubular part of the corolla of calendula4 ,the hairs on cumin fruit vary considerably in size4 ,all the hairs are spreading at the base and blunt or rounded at the apex4 ,the cells forming the hair are narrow and the walls are thick4 ,three differently sized hairs are shown in ,plate #aj1 ,fig4 #a4 ,the hairs of the base of the ligulate petals of calendula 7,plate #aj1 ,fig4 #b7 are biseriate4 ,the hairs are very long and the walls are very thin4 ,multicellular uniseriate branched hairs occur on the leaves of dittany of ,crete1 mullen1 and on the calyx of lavender flowers4 ,the dittany of ,crete 7,plate #aa1 ,fig4 #c7 hair is smooth-walled1 and the branches are alternate4 ,in mullen 7,plate #aa1 ,fig4 #a7 the hairs have whorled branches1 the walls are smooth1 and the cell cavity usually contains air4 ,illustration3 ,,plate #aj ,,multicellular ,,multiseriate ,,non-,,branched ,,hairs #a4 ,cumin 7,cuminum cyminum1 ,l474 #b4 ,marigold 7,calendula officinalis1 ,l474 ,illustration3 ,,plate #aa ,,multicellular ,,uniseriate ,,branched ,,hairs #a4 ,mullen leaf 7,verbascum thapsus1 ,l474 #b4 ,lavender flowers 7,lavandula vera1 ,d4 ,c474 #c4 ,dittany of ,crete 7,origanum dictamnus1 ,l474 ,the lavender hairs 7,plate #aa1 ,fig4 #b7 have mostly opposite branches1 and the walls are rough4 ,thus the multicellular branched hairs may be divided into subgroups which have alternate1 opposite1 whorled1 or in certain hairs irregularly arranged branches4 ,each class may be again subdivided according to color1 character of cell termination1 etc41 as cited at the beginning of the chapter4 ,occasionally multicellular hairs assume the form of a shield 7,plate #ab1 ,fig4 #a72 in such cases the hair is termed peltate1 as in the non-glandular multicellular hair of shepherdia canadensis4 ,hairs grow out from the surface of the epidermis in a perpendicular1 a parallel1 or in an oblique direction4 ,hairs which grow parallel or oblique to the surface are usually curved1 and the outer curved part of the wall is usually thicker than the inner curved wall4 ,the mature hairs of some plants consist of dead cells4 ,in other plants the cells forming the hair are living4 ,when dried1 those hairs1 which were dead before drying1 contain air2 while those hairs which were living before drying1 show great variation in color and in the nature of the cell contents4 ,the contents are either organic or inorganic4 ,the commonest organic constituent is dried protoplasm4 ,in cannabis indica are deposits of calcium carbonate4 ,multicellular multiseriate branched hairs are the ultimate division of the pappus of erigeron1 aromatic goldenrod1 arnica1 grindelia1 boneset1 and life-everlasting4 ,the hairs of erigeron 7,plate #ac1 ,figs4 #a and #b7 are slender2 the walls are porous4 ,each hair terminates in two cells1 which are greatly extended and sharp-pointed2 the branches from the basal part of the hairs 7,plate #ac1 ,fig4 #a7 are of about the same length as the apical branches4 ,the hairs of aromatic goldenrod 7,plate #ac1 ,figs4 #c and #d7 are larger than those of erigeron2 the diameter is greater and the walls are non-porous4 ,the apex of the hair terminates in a group of about four cells of unequal length1 which are sharp-pointed4 ,the branches of the basal cells 7,plate #ac1 ,fig4 #c7 are similar to the branches of the apical cells4 ,the hairs of arnica 7,plate #ad1 ,figs4 #a and #b7 have thick1 strongly porous walls2 the branches terminate in sharp points4 ,the apex of the hair terminates in a single cell4 ,the basal branches 7,plate #ad1 ,fig4 #b7 are much longer than special branches4 ,illustration3 ,,plate #ab ,,non-,,glandular ,,multicellular ,,hairs ,shepherdia canadensis1 ,l4 ,nutt4 ,illustration3 ,,plate #ac ,,multicellular ,,multiseriate ,,branched ,,hairs #a4 ,basal hairs of erigeron 7,erigeron canadensis1 ,l474 #b4 ,apical hairs of erigeron 7,erigeron canadensis1 ,l474 #c4 ,basal hairs of aromatic goldenrod 7,solidago odora1 ,ait474 #d4 ,apical hairs of aromatic goldenrod 7,solidago odora1 ,ait474 ,the hair of grindelia 7,plate #ad1 ,figs4 #c and #d7 has very thick walls with numerous elongated pores4 ,the apex of the hair terminates in a cluster of cells with short1 free1 sharp-pointed ends4 ,the basal branches 7,plate #ad1 ,fig4 #d7 are longer than the apical branches4 ,boneset hair 7,plate #ae1 ,figs4 #a and #b7 has non-porous walls4 ,the apex of the hair terminates in two blunt-pointed cells4 ,the terminal wall is thicker than the side wall4 ,some of the branches lower down terminate in cells with very thick or solid points4 ,the basal branches 7,plate #ae1 ,fig4 #a7 are longer1 but the cells are narrower and more strongly tapering than are the branches of the apical part of the hair4 ,life-everlasting 7,plate #ae1 ,figs4 #c and #d7 has uniformly thickened but non-porous walls4 ,the hair terminates in two blunt-pointed1 greatly elongated cells4 ,the basal branches 7,plate #ae1 ,fig4 #d7 are narrower1 slightly tapering1 and the base of the branches frequently curve downward4 ,the cell cavities of these hairs are filled with air4 ,the walls of hairs are composed of cutin1 of lignin1 and of cellulose4 ,,periderm ,the periderm is the outer protective covering of the stems and roots of mature shrubs and trees4 ,the periderm replaces the epidermis4 ,the periderm may be composed of cork cells1 stone cell-cork1 or a mixture of cork1 parenchyma1 fibres1 stone cells1 etc4 ,,cork ,,periderm ,the typical periderm is made up of cork cells4 ,cork cells vary in appearance1 according to the part of the cell viewed4 ,illustration3 ,,plate #ad ,,multicellular ,,multiseriate ,,branched ,,hairs #a4 ,apical hairs arnica 7,arnica montana1 ,l474 #b4 ,basal hairs arnica 7,arnica montana1 ,l474 #c4 ,apical hairs grindelia 7,grindelia squarrosa1 ,pursh ,dunal74 #d4 ,basal hairs grindelia 7,grindelia squarrosa1 ,pursh ,dunal74 ,illustration3 ,,plate #ae ,,multicellular ,,multiseriate ,,branched ,,hairs #a4 ,apical hairs boneset 7,eupatorium perfoliatum1 ,l474 #b4 ,basal hairs boneset 7,eupatorium perfoliatum1 ,l474 #c4 ,apical hairs life-everlasting 7,gnaphalium obtusifolium1 ,l474 #d4 ,basal hairs life-everlasting 7,gnaphalium obtusifolium1 ,l474 ,on surface view 7,plate #af1 ,fig4 ,a7 the cork cells are angled in outline and are made up of from four to seven side walls2 five- and six-sided cells are more common than the four-and seven-sided cells4 ,surface sections of cork cells show their length and width4 ,these side walls usually appear nearly white1 while the end wall1 particularly of the outermost cork cells1 usually appears brown or reddish-brown1 or in some cases nearly black4 ,cork cells on cross-section are rectangular in form1 and they are arranged in superimposed rows1 the number of rows being gradually increased as the plant grows older4 ,such an increase in the number of rows of cork cells is shown in the cross-section of cascara sagrada 7,plate #af1 ,fig4 ,c74 ,cork cells fit together so closely that there is no intercellular spaces between the cells4 ,in this case two rows of cork cells occupy no greater space than the solitary row of cork cells immediately over and external to them4 ,as a rule1 the outermost layers of cork cells have a narrower radial diameter than the cork cells of the underlying layers4 ,this is due to the fact that these outer cells are stretched as the stem increases in diameter4 ,this view shows the height of cork cells1 but not always the length1 which will1 of course1 vary according to the part of the cell cut across4 ,in a section a few millimeters in diameter1 however1 all the variations in size may be observed4 ,the color of the walls is nearly white4 ,the cavity may contain tannin or other substances4 ,when tannin is present1 the cavity is of a brownish or brownish-red color1 or it may be nearly black4 ,most barks appear devoid of any colored or colorless cell contents4 ,the radial section 7,plate #af1 ,fig4 ,b7 of cork cells shows the height of the cells and the width of the cells at the point cut across4 ,some cells will be cut across their longest diameter1 while others will be cut across their shortest diameter4 ,cork cells are1 therefore1 smaller in radial section than they are in cross-section4 ,the color of the walls is white1 and the color and nature of the cell contents vary for the same reasons that they vary in cross-sections4 ,the number of layers of cork cells occurring in cross- and radial-sections varies according to the age of the plant1 to the type of plant1 and to the conditions under which the plant is growing4 ,the number of layers of cork cells is not of diagnostic importance1 nor is the surface view of cork cells diagnostic except in certain isolated cases4 ,illustration3 ,,plate #af ,,periderm ,,of ,,cascara ,,sagrada 7,rhamnus purshiana1 ,d4,c47 ,a4 #a1 ,outline of cork cells2 #b1 ,line of contact of adjoining cork cells4 ,b4 ,radial longitudinal section of cascara sagrada4 #a1 ,cork cells2 #b1 ,phellogen2 #c1 ,forming parenchyma cells2 #d1 ,cortical parenchyma cells4 ,c4 ,cross-section of cascara sagrada4 #a1 ,cork cells2 #b1 ,phellogen2 #c1 ,forming parenchyma cells2 #d1 ,cortical parenchyma cells4 ,the presence or absence of cork or epidermal tissue in powders must always be noted4 ,the presence of cork enables one to distinguish ,spanish from ,russian licorice4 ,in like manner1 the presence of epidermis enables one to distinguish the pharmacopial from the unofficial peeled calamus4 ,the absence of epidermis in ,jamaica ginger is one of the means by which this variety is distinguished from the other varieties of ginger1 etc4 ,in canella alba the periderm is replaced by stone cell-cork4 ,that is1 the cells forming the periderm are of a typical cork shape1 but the walls are lignified1 unequally thickened1 and the inner or thicker walls are strongly porous1 and the walls are of a yellowish color4 ,stone cell-cork forms the periderm of clove bark also1 but the cells are narrower and longer1 and the inner wall is not so thick or porous as is the case in canella alba bark4 ,,stone ,,cell ,,periderm ,in canella alba 7,plate #ag1 ,fig4 ,b7 cork periderm is frequently replaced by stone cells1 particularly in the older barks4 ,these stone cells form the periderm because they replace the cork periderm1 which fissures and scales off as the root increases in diameter4 ,the side and end walls of cork cells are of nearly uniform diameter4 ,exceptions occur1 but they are not common4 ,in buchu stem 7,plate #aja1 ,fig4 #c71 the cork cells have thick outer walls1 but thin sides and inner walls4 ,the cell cavity contains reddish-brown deposits of tannin4 ,,parenchyma ,,and ,,stone ,,cell ,,periderm ,as the trees and shrubs increase in diameter1 cracks or fissures occur in the periderm1 or corky layer4 ,in such cases the phellogen cells divide and redivide in such manner as to cut off a portion of the parenchyma cells1 stone cells1 and fibres of the cortex which is inside of and below the fissure4 ,all the parenchyma cells1 etc41 exterior to the newly formed cork cells soon lose their living-cell contents1 since their food-supply is cut off by the impervious walls of the cork cells4 ,in time they are forced outward by the developing cork cells until they partially or completely fill the break in the periderm4 ,in white oak bark 7,plate #ah71 as in other barks1 a large part of the periderm is composed of dead and discolored cortical cells4 ,illustration3 ,,plate #ag ,a4 ,cross-section of ,mandrake ,rhizome 7,podophyllum peltatum1 ,l474 #a4 ,epidermis4 #b4 ,phellogen4 #c4 ,cortical parenchyma4 ,b4 ,stone cell periderm of white cinnamon 7,canella alba1 ,murr474 ,illustration3 ,,plate #ah ,,periderm ,,of ,,white ,,oak 7,quercus alba1 ,l47 #a4 ,outer layer of cork cells4 #b4 ,cortical parenchyma cells4 #c4 ,stone cells4 #d4 ,phellogen4 #e4 ,cortical parenchyma cells4 ,,origin ,,of ,,cork ,,cells ,the cork cells are formed by the meristimatic phellogen cells1 which originate from cortical parenchyma4 ,these cells divide into two cells1 the outer changing into a cork cell1 while the inner cell remains meristimatic4 ,in other instances the outer cell remains meristimatic1 while the inner cell changes into a cortical parenchyma cell4 ,the development of a cortical parenchyma cell from a divided phellogen cell is shown in ,plate #aja1 ,fig4 #f4 ,both the primary and secondary cork cells originate from the phellogen or cork cambrium layer4 ,cork cells do not contain living-cell contents2 in fact1 in the majority of medicinal barks the cork cells contain only air4 ,the walls of typical cork cells are composed1 at least in part1 of suberin1 a substance which is impervious to water and gases4 ,in certain cases layers of cellulose1 lignin1 and suberin have been identified4 ,suberin1 however1 is present in all cork cells1 and in some cases all of the walls of cork cells are composed of suberin4 ,suberized cork cells are colored yellow with strong sodium hydroxide solutions and by chlorzinciodide4 ,,chapter ,,iii ,,mechanical ,,tissues ,the mechanical tissues of the plant form the framework around which the plant body is built up4 ,these tissues are constructed and placed in such a manner in the different organs of the plant as to meet the mechanical needs of the organ4 ,many underground stems and roots which are subjected to radial pressure have the hypodermal and endodermal cells arranged in the form of a non-compressible cylinder4 ,such an arrangement is seen in sarsaparilla root 7,plate #ch1 ,fig4 #d74 ,the mechanical tissue of the stem is arranged in the form of solid or hollow columns in order to sustain the enormous weight of the branches4 ,in roots the mechanical tissue is combined in ropelike strands1 thereby effectively resisting pulling stresses4 ,the epidermis of leaves subjected to the tearing force of the wind has epidermal cells with greatly thickened walls1 particularly at the margin of the leaf4 ,the epidermal cells of most seeds have very thick and lignified cell walls1 which effectively resist crushing forces4 ,the cells forming mechanical tissues are3 bast fibres1 wood fibres1 collenchyma cells1 stone cells1 testa epidermal cells1 and hypodermal and endodermal cells of certain plants4 ,the walls of the cells forming mechanical tissues are thick and lignified1 with the exception of the collenchyma cells and a few of the fibres4 ,lignified cells are as resistive to pulling and other stresses as similar sized fragments of steel4 ,the hardness of their wall and their resistance to crushing explain the fact that they usually retain their form in powdered drugs and foods4 ,,bast ,,fibres ,one of the most important characters to be kept in mind in studying bast fibres is the structure of the wall4 ,in fact1 the author's classification of bast fibres is based largely on wall structure4 ,such a classification is logical and accurate1 because it is based upon permanent characters4 ,another character used in classifying bast fibres is the nature of the cell1 whether branched or non-branched4 ,in fact1 this latter character is used to separate all bast fibres into two fundamental groups--namely1 branched bast fibres and non-branched bast fibres4 ,the third important character utilized in classifying fibres is the presence or absence of crystals4 ,bast fibres are classified as follows3 #a4 ,crystal bearing4 #b4 ,non-crystal bearing4 ,the crystal-bearing fibres are divided into two classes3 #a4 ,of leaves4 #b4 ,of barks4 ,the non-crystal bearing are divided into3 #a4 ,branched4 #b4 ,non-branched4 ,the branched and non-branched are divided into four classes3 #a4 ,non-porous and non-striated4 #b4 ,porous and non-striated4 #c4 ,striated and non-porous4 #d4 ,porous and striated4 ,,crystal-,,bearing ,,bast ,,fibres ,the crystal-bearing fibres are composed 7#a7 of groups of fibres1 7#b7 of crystal cells1 and 7#c7 of crystals4 ,in these cases the groups of fibres are large1 and they are frequently completely covered by crystal cells1 which may or may not contain a crystal4 ,the crystals found on the fibres from the different plants vary considerably in size and form4 ,as a rule1 the fibres when separated are free of crystal cells and crystals4 ,this is so because the crystal cells are exterior to the fibres1 and in separating the fibres during the milling process the crystal cells are broken down and removed from the fibres4 ,it is common1 therefore1 to find isolated fibres and crystals associated with the crystal-bearing fibres4 ,the fibres which are crystal-bearing may be striated or porous1 etc42 but owing to the fact that the grouping of the fibres and crystals is so characteristic1 little or no attention is paid to the structure of the individual fibres4 ,illustration3 ,,plate #ai ,,crystal-,,bearing ,,fibres ,,of ,,barks #a4 ,frangula 7,rhamnus frangula1 ,l474 #b4 ,cascara sagrada 7,rhamnus purshiana1 ,d4,c474 #c4 ,spanish licorice 7,glycyrrhiza glabra1 ,l474 #d4 ,witch-hazel bark 7,hamamelis virginiana1 ,l474 ,crystal-bearing fibres occur in the barks of frangula 7,plate #ai1 ,fig4 #a72 cascara sagrada 7,plate #ai1 ,fig4 #b72 witch-hazel 7,plate #ai1 ,fig4 #d72 in cocillana 7,plate #bj1 ,fig4 #a72 in white oak 7,plate #bj1 ,fig4 #b72 in quebracho 7,plate #bj1 ,fig4 #c72 and in ,spanish licorice root 7,plate #ai1 ,fig4 #c74 ,the crystal-bearing fibres of leaves are always associated with vessels or tracheids and with cells with chlorophyl4 ,the presence or absence of crystal-bearing fibres in leaves should always be noted4 ,the crystal-bearing fibres of leaves are composed of fragments of conducting cells1 fibres1 crystal cells1 and crystals4 ,the crystal-bearing fibres of leaves occur in larger fragments than the other parts of the leaf1 because the fibres are more resistant to powdering4 ,having observed that a leaf has crystal-bearing fibres1 in order to identify the powder it is necessary to locate one of the other diagnostic elements of the leaf--as the papill of coca 7,plate #ba1 ,fig4 #a71 or the hair of senna 7,plate #ba1 ,fig4 #c71 or the vessels in eucalyptus 7,plate #ba1 ,fig4 #b74 ,branched bast fibres occur in only a few of the medicinal plants1 notable examples being tonga root and sassafras root4 ,occasionally one is found in mezereum bark4 ,the bast fibre of tonga root 7,plate #bb1 ,fig4 #b7 often has seven branches1 but four- and five-branched forms are more common4 ,the walls are non-porous1 non-striated1 and nearly white4 ,the bast fibre of sassafras 7,plate #bb1 ,fig4 #a7 has thick1 non-porous1 and non-striated walls1 and the branching occurs usually at one end only of the fibre4 ,most of the bast fibres of sassafras root are non-branched4 ,,porous ,,and ,,striated ,,bast ,,fibres ,porous and striated walled bast fibres occur in blackberry bark of root1 wild-cherry bark1 and in cinchona bark4 ,the fibres of blackberry root bark 7,plate #bc1 ,fig4 #a7 have distinctly porous and striated walls2 the cavity1 which is usually greater than the diameter of the wall1 contains starch4 ,these fibres usually occur as fragments4 ,in wild-cherry bark 7,plate #bc1 ,fig4 #b7 the fibre has short1 thick1 unequally thickened walls1 which are porous and striated4 ,most of the fibres are unbroken4 ,illustration3 ,,plate #bj ,,crystal-,,bearing ,,fibres ,,of ,,barks #a4 ,cocillana 7,guarea rusbyi1 ,britton ,rusby74 #b4 ,white oak 7,quercus alba1 ,l47 #c4 ,quebracho 7,aspidosperma quebracho-blanco1 ,schlechtendal74 ,illustration3 ,,plate #ba ,,crystal-,,bearing ,,fibres ,,of ,,leaves #a4 ,coca leaf 7,erythroxylon coca1 ,lam474 #b4 ,eucalyptus leaf 7,eucalyptus globulus1 ,labill74 #c4 ,senna leaf 7,cassia angustifolia1 ,vahl474 ,illustration3 ,,plate #bb ,,branched ,,bast ,,fibres #a4 ,sassafras root bark 7,sassafras variifolium1 ,salisb4 ,kuntze74 #b4 ,tonga root4 ,yellow cinchona bark 7,plate #bc1 ,fig4 #c7 has very thick1 prominently striated porous-walled fibres1 with either blunt or pointed ends4 ,the cavity is narrow1 and the pores are simple or branched4 ,,porous ,,and ,,non-,,striated ,,bast ,,fibres ,porous and non-striated bast fibres occur in marshmallow root and echinacea root4 ,the fibres of marshmallow 7,plate #bd1 ,fig4 #c7 usually occur in fragments4 ,the walls have simple pores1 and the diameter of the cell cavity is very wide2 the pores on the upper or lower wall are circular or oval in outline 7end view74 ,the bast fibres of echinacea root 7,plate #bd1 ,fig4 #d7 are seldom broken2 the walls are yellow1 the pores are simple and numerous4 ,the edges and surface of the fibres are frequently covered with a black intercellular substance4 ,,non-,,porous ,,and ,,striated ,,bast ,,fibres ,non-porous and striated bast fibres occur in elm bark1 stillingia root1 and cundurango bark4 ,the bast fibres of elm bark 7,plate #be1 ,fig4 #a7 occur in broken1 curved1 or twisted fragments4 ,the central cavity is very small1 and the walls are longitudinally striated4 ,in powdered stillingia root 7,plate #be1 ,fig4 #b7 the bast fibres are broken1 and the wall is very thick and longitudinally striated4 ,the central cavity is small and usually not visible4 ,bast fibres of cundurango 7,plate #be1 ,fig4 #c7 are broken in the powder4 ,the cavity is very narrow1 and the striations are arranged spirally1 less frequently transversely4 ,,non-,,porous ,,and ,,non-,,striated ,,bast ,,fibres ,non-porous and non-striated walled bast fibres occur in mezereum bark1 in ,ceylon cinnamon1 in sassafras root bark1 and in soap bark4 ,the simplest non-porous and non-striated walled bast fibres are found in mezereum bark 7,plate #bf1 ,fig4 #d74 ,the individual fibre is very long4 ,it often measures over three millimeters in length1 so that in the powder the fibre is usually broken4 ,the wall is non-lignified1 white1 non-porous1 and of uniform diameter4 ,illustration3 ,,plate #bc ,,porous ,,and ,,striated ,,bast ,,fibres #a4 ,blackberry root 7,rubus cuneifolius1 ,pursh474 #b4 ,wild cherry 7,prunus serotina1 ,ehrh474 #c4 ,yellow cinchona 7,cinchona species74 ,illustration3 ,,plate #bd ,,porous ,,and ,,non-,,striated ,,bast ,,fibres #a4 ,sarsaparilla root 7,hypoderm71 7,smilax officinalis1 ,kunth74 #b4 ,unicorn root 7,endoderm74 #c4 ,marshmallow root 7,altha officinalis1 ,l474 #d4 ,echinacea root 7,echinacea angustifolia1 ,d4 ,c474 ,illustration3 ,,plate #be ,,non-,,porous ,,and ,,striated ,,bast ,,fibres #a4 ,elm bark 7,ulmus fulva1 ,michaux74 #b4 ,stillingia root 7,stillingia sylvatica1 ,l474 #c4 ,cundurango root bark 7,marsdenia cundurango1 ,triana ,nichols74 ,in ,ceylon cinnamon 7,plate #bf1 ,fig4 #b7 the bast fibres measure up to 4#ijj mm4 in length1 so that in powdering the bark the fibre is rarely broken4 ,these bast fibres1 unlike the bast fibres of mezereum1 have thick1 white walls and a narrow cell cavity4 ,both ends of the fibre taper gradually to a long1 narrow point4 ,in ,saigon cinnamon the bast fibres are not as numerous as they are in ,ceylon cinnamon4 ,the individual fibres are thicker than in ,ceylon cinnamon1 and the walls are yellowish and rough and the ends bluntly pointed4 ,these fibres are rarely ever free from adhering fragments of parenchyma tissue4 ,in sassafras root bark 7,plate #bf1 ,fig4 #c7 the fibre has one nearly straight side--the side in contact with the other bast fibres--and an outer side with a wavy outline1 caused by the fibre's pressing against parenchyma cells1 the point of highest elevation being the point of the fibre's growth into the intercellular space between two cells4 ,the outer part of the wall tapers gradually at either end to a sharp point4 ,the walls are white1 thick1 and non-porous4 ,in soap bark 7,plate #bf1 ,fig4 #a7 the bast fibres have thick1 white1 wavy walls and a narrow cavity4 ,one end of the cell is frequently somewhat blunt while the opposite end is slightly tapering4 ,the branched stone cells of wild-cherry bark have three or more branches4 ,the pores are small and usually non-branched1 and the striations are very fine and difficult to see unless the iris diaphragm is nearly closed4 ,the central cavity is very narrow and frequently contains brown tannin4 ,the branched stone cells of hemlock bark are very large2 the walls are white and distinctly porous bordering on the cell cavity1 which contains bright reddish-brown masses of tannin4 ,in cross-section bast fibres occur singly or isolated1 as in ,saigon cinnamon 7,plate #cd1 ,fig4 #a72 or in groups1 as in menispermum 7,plate #bg1 ,figs4 #a and #b72 or in the form of continuous bands1 as in buchu stem 7,plate #ajj1 ,fig4 #e74 ,bast fibres are seen in longitudinal view in powdered drugs4 ,the cell cavity shows throughout the length of the fibre4 ,this cavity differs greatly in different fibres4 ,in soap bark 7,plate #bf1 ,fig4 #a7 there is scarcely any cell cavity1 while in mezereum bark 7,plate #bf1 ,fig4 #d7 the cell cavity is very large4 ,illustration3 ,,plate #bf ,,non-,,porous ,,and ,,non-,,striated ,,bast ,,fibres #a4 ,soap bark 7,quillaja saponaria1 ,molina74 #b4 ,ceylon cinnamon bark 7,cinnamomum zeylanicum1 ,nees74 #c4 ,sassafras root bark 7,sassafras variifolium1 ,salisb4 ,kuntze74 #d4 ,mezereum bark 7,daphne mezereum1 ,l474 ,illustration3 ,,plate #bg ,,groups ,,of ,,bast ,,fibres #a4 ,menispermum rhizome 7,menispermum canadensis1 ,l474 #b4 ,althea root 7,altha officinalis1 ,l47 showing two groups of bast fibres4 ,the pores1 which are absent in many drugs1 are1 when present1 either simple1 as in echinacea root 7,plate #bd1 ,fig4 #d71 or they are branched1 as in yellow cinchona 7,plate #bc1 ,fig4 #c74 ,in each of the above fibres the length and width of the fibre are shown4 ,the fibres also have pores of variable length4 ,such a variation is common to most fibres with pores4 ,that part of the wall immediately over or below the cell cavity shows the end view or diameter of the pore1 as in the fibre of marshmallow root 7,plate #bd1 ,fig4 #c74 ,as a rule1 however1 the pores show indistinctly on the upper and lower wall4 ,,occurrence ,,in ,,powdered ,,drugs ,in powdered drugs bast fibres occur singly or in groups4 ,the individual fibres may be broken1 as in mezereum and elm bark1 or they may be entire1 as in ,ceylon cinnamon and in sassafras bark 7,plate #bf1 ,figs4 #b and #c74 ,the lignified walls of bast fibres are colored red by a solution of phlorogucin and hydrochloric acid1 and the walls are stained yellow by aniline chloride4 ,in fact1 few of the fibres found in individual plants occur in a broken condition4 ,isolated bast fibres are circular in outline4 ,bast fibres1 when forming part of a bundle1 have angled outlines when they are completely surrounded by other bast fibres2 but when they occur on the outer part of the bundle1 and when in contact with parenchyma or other cortical cells1 they are partly angled and partly undulated in outline4 ,in the bast fibres the pores are placed at right angles to the length of the fibre4 ,the side walls show the length of the pore 7,plate #bd1 ,fig4 #c72 while the upper or lower wall shows the outline1 which is circular1 and the pore1 which is very minute4 ,most bast fibres have no cell contents4 ,in some cases1 however1 starch occurs1 as in the bast fibres of rubus4 ,the color of the bast fibres varies1 being colorless1 as in ,ceylon cinnamon2 or yellowish-white1 as in echinacea2 or bright yellow1 as in bayberry bark4 ,bast fibres retain their living-cell contents until fully developed2 then they die and function largely in a mechanical way4 ,the walls of bast fibres are composed of cellulose or of lignin4 ,most of the bast fibres occurring in the medicinal plants give a strong lignin reaction4 ,,wood ,,fibres ,wood fibres always occur in cross-sections associated with vessels and wood parenchyma1 from which they are distinguished by their thicker walls1 smaller diameter1 and by the nature of the pores1 which are usually oblique and fewer in number than the pores in the walls of wood parenchyma1 and different in form from the pores of vessels4 ,the wood fibre on cross-section 7,plate #aje1 ,fig4 #d7 shows an angled outline1 except in the case of the fibres bordering the pith-parenchyma1 etc41 in which case they are rounded on their outer surface1 but angled at the points in contact with other fibres4 ,the pore of wood fibres is one of the main characteristics which enable one to distinguish the wood fibres from bast fibres4 ,the pores are slanting or strongly oblique 7,plate #bh1 ,fig4 #b71 and they show for their entire length on the broadest part of the wall--i4e41 the upper or the lower surface--while in the side wall they are oblique2 but they are not so distinct as they are on the broad part of the wall4 ,frequently the pores appear crossed when the upper and the lower wall are in focus1 because the pores are spirally arranged1 and the pore on the under wall throws a shadow across the pore on the upper wall1 or vice versa4 ,wood fibres always occur in a broken condition 7,plate #bh1 ,fig4 #a7 in powdered drugs4 ,these broken fibres usually occur both singly and in groups in a given powder4 ,the color of wood fibres varies greatly in the different medicinal woods4 ,fragments of wood are usually adhering to witch-hazel1 black haw1 and other medicinal barks4 ,in each of these cases the wood fibres are nearly colorless4 ,in barberry bark adhering fragments of wood and the individual fibres are greenish-yellow4 ,the wood fibres of santalum album are whitish-brown2 of quassia1 whitish-yellow2 of logwood and santalum rubrum1 red4 ,illustration3 ,,plate #bh ,,wood ,,fibres #a4 ,white sandalwood 7,santalum album1 ,l474 #b4 ,quassia wood 7,picrna excelsa1 ,swartz ,lindl474 #c4 ,logwood with crystals 7,hmatoxylon campechianum1 ,l474 #d4 ,black haw root 7,viburnum prunifolium1 ,l474 ,some wood fibres function as storage cells4 ,in quassia the wood fibres frequently contain storage starch4 ,the wood fibres of logwood and red saunders contain coloring substances1 which are partially in the cell cavity and partially in the cell wall4 ,the walls of wood are composed largely of lignin4 ,,collenchyma ,,cells ,collenchyma cells form the principal medicinal tissue of stems of herbs1 petioles of leaves1 etc4 ,in certain herbs the collenchyma forms several of the outer layers of the cortex of the stem4 ,in motherwort1 horehound1 and in catnip the collenchyma cells occur chiefly at the angles of the stem4 ,in motherwort 7,plate #bi1 ,fig4 ,b7 there are twelve bundles1 one large bundle at each of the four angles1 and two small bundles1 one on either side of the large bundle4 ,in catnip 7,plate #bi1 ,fig4 ,a7 there are four large masses1 one at each angle of the stem4 ,collenchyma cells differ from parenchyma cells in a number of ways3 first1 the cell cavity is smaller2 secondly1 the walls are thicker1 the greater amount of thickening being at the angles of the cells--that is1 the part of the cell wall which is opposite the usual intercellular space of parenchyma cells1 while the wall common to two adjoining cells usually remains unthickened4 ,in horehound stem 7,plate #cj1 ,fig4 #b7 the thickening is so great at the angles that no intercellular space remains4 ,in the side column of motherwort stem 7,plate #cj1 ,fig4 #a7 the thickening between the cells has taken place to such an extent that the cell cavities become greatly separated and arranged in parallel concentric rows4 ,the collenchyma of the outer angle of motherwort stem 7,plate #cj1 ,fig4 #c7 is greatly thickened at the angles4 ,there are no intercellular spaces between the cells1 and cell cavity is usually angled in outline instead of circular1 as in the cells of horehound4 ,in certain plants intercellular spaces occur between the cells1 and the walls are striated instead of being non-striated1 as in the stems of horehound1 motherwort1 and catnip4 ,illustration3 ,,plate #bi ,a4 ,diagrammatic sketch of the cross-section of catnip stem 7,nepeta cataria1 ,l474 #a4 ,collenchyma occurring at the four angles of the stem4 ,b4 ,diagrammatic sketch of the cross-section of motherwort stem 7,leonurus cardiaca1 ,l474 #a1 #b1 #c4 ,twelve masses of collenchyma tissue occurring at the four sides of the stem4 ,illustration3 ,,plate #cj ,,collenchyma ,,cells #a4 ,cross-section of a side column of the collenchyma of motherwort stem 7,leonurus cardiaca1 ,l474 #b4 ,cross-section of the collenchyma of horehound stem 7,marrubium vulgare1 ,l474 #c4 ,cross-section of the collenchyma of the outer angle of motherwort stem4 ,collenchyma cells retain their living contents at maturity4 ,many collenchyma cells1 particularly of the outer layers of bark and the collenchyma of the stems of herbs1 contain chlorophyll4 ,the walls of collenchyma consist of cellulose4 ,,stone ,,cells ,stone cells1 like bast fibres1 are branched or non-branched4 ,each group is then separated into subgroups according to wall structure 7whether striated1 or pitted and striated1 etc471 thickness of wall and of cell cavity1 color of wall and of cell contents1 absence of color and of cell contents1 etc4 ,,branched ,,stone ,,cells ,branched stone cells occur in a number of drugs4 ,in witch-hazel bark 7,plate #ca1 ,fig4 #b7 the walls are thick1 white1 and very porous4 ,in some cells the branches are of equal length2 in others they are unequal4 ,in the tea-leaf 7,plate #ca1 ,fig4 #a7 the walls are yellowish white and finely porous4 ,when the lower wall is brought in focus1 it shows numerous circular pits4 ,these pits represent the pores viewed from the end4 ,the branches frequently branch or fork4 ,branched stone cells also occur in coto bark1 acer spicatum1 star-anise1 witch-hazel leaf1 hemlock1 and wild-cherry barks4 ,non-branched stone cells are divided into two main groups1 as follows3 #a4 ,porous and striated stone cells1 and1 #b4 ,porous and non-striated stone cells4 ,,porous ,,and ,,striated ,,stone ,,cells ,porous and striated walled stone cells occur in ruellia root1 winter's bark1 bitter root1 allspice1 and aconite4 ,these stone cells are shown in ,plate #cc1 ,figs4 #a1 #b1 #c1 #d1 and #e4 ,the stone cells of ruellia root 7,plate #cb1 ,fig4 #a7 are greatly elongated1 rectangular in form1 with thick1 white1 strongly porous walls4 ,the central cavity is narrow and is marked with prominent pores and striations4 ,the stone cells of winter's bark 7,plate #cb1 ,fig4 #b7 vary from elongated to nearly isodiametric4 ,the pores are very large1 the light yellowish wall is irregularly thickened1 and the central cavity is very large4 ,the pores are prominent4 ,illustration3 ,,plate #ca ,,branched ,,stone ,,cells #a4 ,tea leaf 7,thea sinensis1 ,l474 #b4 ,witch-hazel bark 7,hamamelis virginiana1 ,l474 #c4 ,hemlock bark 7,tsuga canadensis1 ,l4 ,carr74 #d4 ,wild-cherry bark 7,prunus serotina1 ,ehrh474 ,the stone cell of bitter root 7,plate #cb1 ,fig4 #c7 is nearly isodiametric4 ,the walls are yellowish white and strongly porous and striated4 ,the central cavity is about equal to the thickness of the walls4 ,the stone cell of allspice 7,plate #cb1 ,fig4 #d7 is mostly rounded in form1 and when the outer wall only is in focus it shows numerous round and elongated pores4 ,the central cavity is filled with masses of reddish-brown tannin4 ,the striations are very prominent4 ,the diagnostic stone cell of aconite 7,plate #cb1 ,fig4 #e7 is rectangular or square in outline2 the walls are yellowish and the central cavity has a diameter many times the thickness of the wall4 ,the side and surface view of the pores is prominent1 and the striations are very fine4 ,,porous ,,and ,,non-,,striated ,,stone ,,cells ,porous and non-striated stone cells occur in ,ceylon cinnamon1 in calumba root1 in dogwood bark1 in cubeb1 and in echinacea root4 ,the diagnostic stone cells of ,ceylon cinnamon 7,plate #cc1 ,fig4 #a7 are nearly square in outline2 the walls are strongly porous and the large central cavity frequently contains starch4 ,the stone cells of calumba root 7,plate #cc1 ,fig4 #b7 vary in shape from rectangular to nearly square1 and the walls are greenish yellow1 unequally thickened1 and strongly porous4 ,the typical stone cells contain several prisms1 usually four4 ,the stone cells of dogwood bark 7,plate #cc1 ,fig4 #c7 have thick1 white walls with simple and branched pores4 ,the central cavity frequently branches and appears black when recently mounted1 owing to the presence of air4 ,the stone cells of cubeb 7,plate #cc1 ,fig4 #d7 are very small1 mostly rounded in outline1 with a great number of very fine simple pores which extend from the outer wall to the central cavity4 ,the wall is yellow and very thick4 ,the stone cells of echinacea root 7,plate #cc1 ,fig4 #e7 are very irregular in form2 the walls are yellowish and porous1 and the central cavity is very large4 ,a black intercellular substance is usually adhering to portions of the outer wall4 ,the color of the walls of the different stone cells is very variable4 ,in ,ceylon cinnamon and ruellia the walls are colorless2 in zanthoxylium1 light yellow2 in rumex1 deep yellow2 in cascara sagrada1 greenish yellow4 ,the pores of stone cells1 like the pores of bast fibres1 are either simple or branched1 and they may or may not extend through the entire wall4 ,many of the shorter pores extend for only a short distance from the cell cavity4 ,the width of the cell cavity varies considerably in the stone cells of the different plants4 ,in aconite 7,plate #cb1 ,fig4 #e71 in calumba 7,plate #cc1 ,fig4 #b71 and in ,ceylon cinnamon 7,plate #cc1 ,fig4 #a71 the cell cavity is several times greater than the thickness of the cell wall4 ,in allspice 7,plate #cb1 ,fig4 #d71 in bitter root 7,plate #cb1 ,fig4 #c71 the diameter of the cell cavity and the thickness of the wall are about equal4 ,in cubeb 7,plate #cc1 ,fig4 #d71 in ruellia 7,plate #cb1 ,fig4 #a71 the wall is thicker than the diameter of the cell cavity4 ,the cavity of many stone cells contains no characteristic cell contents4 ,in other stone cells the cell contents are as characteristic as the stone cell4 ,the stone cells of both ,saigon and ,ceylon cinnamon 7,plate #cc1 ,fig4 #a7 contain starch2 the stone cells of calumba 7,plate #cc1 ,fig4 #b7 contain prisms of calcium oxalate2 the stone cells of allspice and sweet-birch bark contain tannin4 ,in cross-sections1 stone cells occur singly1 as in ,saigon cinnamon 7,plate #cd1 ,fig4 #a71 ruellia 7,plate #cd1 ,fig4 #b72 in groups1 as in cascara sagrada 7,plate #cd1 ,fig4 #c72 and in continuous bands1 as in ,saigon cinnamon 7,plate #cd1 ,fig4 #d74 ,in powdered drugs1 stone cells1 like bast fibres1 occur singly1 as in ruellia1 calumba1 etc42 or in groups1 as in cascara sagrada1 witch-hazel bark1 etc4 ,in most powders they occur both singly and in groups4 ,the individual stone cells are mostly entire1 as in ruellia1 calumba1 allspice1 echinacea1 etc4 ,in cascara sagrada many of the stone cells are broken when the closely cemented groups are torn apart in the milling process4 ,many of the branched stone cells of witch-hazel bark and leaf1 wild cherry1 etc41 also occur broken in the powder4 ,illustration3 ,,plate #cb ,,porous ,,and ,,striated ,,stone ,,cells #a4 ,ruellia root 7,ruellia ciliosa1 ,pursh474 #b4 ,winter's-bark 7,drimys winteri1 ,forst474 #c4 ,bitterroot 7,apocynum androsmifolium1 ,l474 #d4 ,allspice 7,pimenta officinalis1 ,lindl474 #e4 ,aconite 7,aconitum napellus1 ,l474 ,illustration3 ,,plate #cc ,,porous ,,and ,,non-,,striated ,,stone ,,cells #a4 ,ceylon cinnamon 7cinnamomum zeylanicum1 ,nees74 #b4 ,calumba root 7,jateorhiza palmata1 ,lam4 ,miers74 #c4 ,dogwood root bark 7,cornus florida1 ,l474 #d4 ,cubeb 7,piper cubeba1 ,l41 f47 #e4 ,echinacea 7,echinacea angustifolia1 ,d4,c474 ,illustration3 ,,plate #cd #a4 ,saigon cinnamon4 #b4 ,ruellia root 7,ruellia ciliosa1 ,pursh474 #c4 ,cascara sagrada 7,rhamnus purshiana1 ,d4,c474 #d4 ,saigon cinnamon4 ,the walls of all stone cells are composed of lignin4 ,the form of stone cells varies greatly2 in aconite the stone cells are quadrangular2 in ruellia they are rectangular2 in pimenta1 they are circular or oval in outline2 in most stone cells they are polygonal4 ,the lignified walls of stone cells are stained red with a solution of phloroglucin and hydrochloric acid1 and the walls are stained yellow by aniline chloride4 ,,endodermal ,,cells ,the endodermal cells of the different plants vary greatly in form1 color1 structure1 and composition of the wall1 yet these different endodermal cells may be divided into two groups3 first1 thin-walled parenchyma-like cells1 and secondly1 thick-walled fibre-like cells4 ,in the thin-walled endodermal cells the walls are composed of cellulose1 and the cell terminations are blunt or rounded4 ,when the drug is powdered1 the cells break up into small diagnostic fragments4 ,in the thick-walled endodermal cells1 the walls are lignified and porous1 and the ends of the cell are frequently pointed and resemble fibres4 ,sarsaparilla root1 triticum1 convallaria1 and aletris have thick-walled endodermal cells4 ,,structure ,,of ,,endodermal ,,cells ,the endodermal cells of sarsaparilla root 7,plate #ce1 ,fig4 #a7 are never more than one layer in thickness4 ,the walls are porous and of a yellowish-brown color4 ,alternating with the thick-walled cell is a thin-walled cell1 which is frequently referred to as a passage cell4 ,the endodermal cells of triticum 7,plate #ce1 ,fig4 #b7 are yellowish1 and the walls are porous and striated4 ,there are one or two layers of cells4 ,the cells forming the outer layer have very thin outer but thick inner walls1 while the cells forming the inner layer are more uniform in thickness4 ,the endodermal cells of convallaria 7,plate #ce1 ,fig4 #c7 are yellowish white in color1 and the walls are porous and striated4 ,the outer wall of the layer of cells is thinner than the inner wall4 ,the innermost layer of cell is more uniformly thickened4 ,illustration3 ,,plate #ce ,,cross-,,sections ,,of ,,endodermal ,,cells ,,of #a4 ,sarsaparilla root 7,smilax officinalis1 ,kunth74 #b4 ,triticum 7,agropyron repens1 ,l474 #c4 ,convallaria 7,convallaria majalis1 ,l474 #d4 ,aletris 7,aletris farinosa1 ,l474 ,the endodermal cells of aletris 7,plate #ce1 ,fig4 #d7 are yellowish brown1 slightly porous and striated4 ,there are one or two layers of these cells1 and two of the smaller cells usually occupy a space similar to that occupied by the radically elongated single cell4 ,on a longitudinal view1 the endodermal cells of sarsaparilla triticum1 convallaria1 and aletris appear as follows3 ,those of sarsaparilla 7,plate #cf1 ,fig4 #a7 are greatly elongated1 the ends of the cells are blunt or slightly pointed1 and the walls appear porous and striated4 ,those of triticum 7,plate #cf1 ,fig4 #b7 are elongated1 the walls are porous and striated1 and the outer wall is much thinner than the inner wall4 ,the end wall between two cells frequently appears common to the two cells4 ,those of convallaria 7,plate #cf1 ,fig4 #c7 are elongated1 and the end wall is usually blunt4 ,the outer wall is thinner than the inner wall4 ,those of aletris 7,plate #cf1 ,fig4 #d7 are fibre-like in appearance2 the ends of the cells are pointed and the wall is strongly porous4 ,the longitudinal view of these cells is shown in plate #cf4 ,,hypodermal ,,cells ,hypodermal cells occur in sarsaparilla root and in triticum4 ,in the cross-section of sarsaparilla root 7,plate #cg1 ,fig4 #a7 the hypodermal cells are yellowish or yellowish brown4 ,the outer wall is thicker than the inner wall1 and the cell cavity is mostly rounded1 and contains air4 ,the walls are porous and finely striated4 ,on longitudinal view1 the hypodermal cells of sarsaparilla 7,plate #cg1 ,fig4 #b7 are greatly elongated1 and the outer and side walls are thicker than the inner walls4 ,the ends of the cells are blunt and distinct from each other4 ,in cross-section1 the hypodermal cells of triticum 7,plate #cg1 ,fig4 #c7 are nearly rounded in outline1 and the walls are of nearly uniform thickness4 ,in longitudinal view 7,plate #cg1 ,fig4 #d7 the same cells appear parenchyma-like1 and the walls between any two cells appear common to the two cells4 ,illustration3 ,,plate #cf ,,longitudinal ,,sections ,,of ,,endodermal ,,cells #a4 ,sarsaparilla root 7,smilax officinalis1 ,kunth74 #b4 ,triticum 7,agropyron repens1 ,l474 #c4 ,convallaria 7,convallaria majalis1 ,l474 #d4 ,aletris 7,aletris farinosa1 ,l474 ,illustration3 ,,plate #cg ,,hypodermal ,,cells #a4 ,cross-section sarsaparilla root 7,smilax officinalis1 ,kunth74 #b4 ,longitudinal section sarsaparilla root 7,smilax officinalis1 ,kunth74 #c4 ,cross-section triticum 7,agropyron repens1 ,l474 #d4 ,longitudinal section triticum 7,agropyron repens1 ,l474 ,,chapter ,,iv ,,absorption ,,tissue ,most plants obtain the greater part of their food1 first1 from the soil in the form of a watery solution1 and1 secondly1 from the air in the form of a diffusible gas4 ,in a few cases all food material is obtained from the air1 as in the case of epiphytic plants4 ,in such plants1 the aerial roots have a modified outer layer--velamen--which functions as a water-absorbing and gas-condensing tissue4 ,many xerophytic plants absorb water through the trichomes of the leaf4 ,such absorption tissue enables the plant to absorb any moisture that may condense upon the leaf and that would not otherwise be available to the plant4 ,the water-absorbing tissue of roots is restricted to the root hairs1 which are found1 with few exceptions1 only on young developing roots4 ,,root ,,hairs ,root hairs usually occur a short distance back of the root cap4 ,there is1 in fact1 a definite zone of the epidermis on which the root hairs develop4 ,this zone is progressive4 ,as the root elongates the root hairs continue to develop1 the zone of hairs always remaining at about the same distance from the root cap4 ,with the development of new zones of growth the hairs on the older zone die off and finally become replaced by an epidermis1 or a periderm1 except in the case of sarsaparilla root1 and possibly other roots that have persistent root hairs4 ,each root hair is an outgrowth from an epidermal cell 7,plate #ch1 ,fig4 #c74 ,the length of the hair and its form depend upon the nature of the soil1 whether loose or compact1 and upon the amount of water present4 ,a root hair is formed by the extension of the peripheral wall of an epidermal cell4 ,at first this wall is only slightly papillate1 but gradually the end wall is extended farther and farther from the surface of the root1 caused by the development of side walls by the growing tip of the root hair until a tube-like structure1 root hair1 is produced4 ,the root hair is then a modified epidermal cell4 ,the protoplast lines the cell1 and the central part of the root hair consists of a large vacuole filled with cell sap4 ,the wall of the root hair is composed of cellulose1 and the outermost part is frequently mucilaginous4 ,as the root hairs develop1 they become bent1 twisted1 and of unequal diameter1 as a result of growing through narrow1 winding soil passages4 ,during their growth1 the root hairs become firmly attached to the soil particles4 ,the walls of root hairs give an acid reaction caused by the solution of the carbon dioxide excreted by the root hair4 ,the acid character of the wall attracts moisture1 and in addition has a solvent action on the insoluble compounds contained in the soil4 ,it will thus be seen that the method of growth1 structure1 composition1 and reaction of the wall of the root hair is perfectly suited to carry on the work of absorbing the enormous quantities of water needed by the growing plant4 ,it is a well-known fact that when two solutions of unequal density are separated by a permeable membrane1 the less dense liquid will pass through the membrane to the denser liquid4 ,the wall of the root hair acts like an osmotic membrane4 ,the less dense watery solution outside the root hair passes through its wall and into the denser cell sap solution4 ,as the solution is absorbed1 it passes from the root hair into the adjoining cortical parenchyma cells4 ,it is a fact that root hairs are seldom found in abundance on medicinal roots4 ,this is due to the fact that root hairs occur only on the smaller branches of the root1 and that when the root is pulled from the ground the smaller roots with their root hairs are broken off and left in the soil4 ,for this reason a knowledge of the structure of root hairs is of minor importance in the study of powdered drugs4 ,an occasional root hair is found1 however1 in most powdered roots1 but root hairs have little or no diagnostic value1 except in false unicorn root and sarsaparilla4 ,when false unicorn root is collected1 most of the root hairs remain attached to the numerous small fibrous roots1 owing to the fact that these roots are easily removed from the sandy soil in which the plants grow4 ,the root hairs of false unicorn are so abundant and so large that they form dense mats1 which are readily seen without magnification4 ,these hairs are1 therefore1 macroscopically as well as microscopically diagnostic4 ,the root hairs of false unicorn 7,plate #ci1 ,fig4 #b7 have white1 wavy1 often decidedly indented walls4 ,the terminal1 or end wall1 is rounded and much thicker than the side walls4 ,illustration3 ,,plate #ch ,,cross-,,section ,,of ,,sarsaparilla ,,root 7,smilax officinalis1 ,kunth7 #a4 ,epidermal cell developing into a root hair4 #b4 ,developing root hair4 #c4 ,nearly mature root hair4 #d4 ,hypodermal cells4 ,illustration3 ,,plate #ci ,,root ,,hairs 7,fragments7 #a4 ,sarsaparilla root 7,smilax officinalis1 ,kunth74 #b4 ,false unicorn root 7,helonias bullata1 ,l474 ,in sarsaparilla 7,plate #ci1 ,fig4 #a7 the root hairs are curved and twisted4 ,the end wall is thicker than the side walls4 ,in some hairs the walls are as thick as the walls of the thin-walled bast fibres4 ,this accounts for the fact that the root hairs are persistent on even the older portions of sarsaparilla root1 and it serves also to explain why these root hairs remain on the root even after being pulled from the firmly packed earth in which the root grows4 ,,water ,,absorption ,,by ,,leaves ,in many xerophytic terrestrial plants1 the trichomes occurring on leaves act as a water-absorbing tissue4 ,in such plants the walls of the hairs are composed largely of cellulose4 ,it is obvious that these hairs absorb the water of condensation caused by dew and light rains--water which could not reach the plant except by such means4 ,there is no special tissue set aside for the absorption of gases from the air4 ,carbon dioxide1 which contributes the element carbon to the starch formed by photosynthesis1 enters the leaf by way of the stoma and lenticels4 ,the structure and the chief functions of these will be considered under arating tissue4 ,,chapter ,v ,,conducting ,,tissue ,all cells of which the primary or secondary function is that of conduction are included under conducting tissue4 ,it will be understood how important the conducting tissue is when the enormous quantity of water absorbed by a plant during a growing season is considered4 ,it will then be realized that the conducting system must be highly developed in order to transport this water from one organ to another1 and1 in fact1 to all the cells of the plant4 ,special attention must be given to the occurrence1 the structure1 the direction of conduction1 and to the nature of the conducted material4 ,the cells or cell groups comprising the conducting tissue are vessels and tracheids1 sieve tubes1 medullary ray cells1 latex tubes1 and parenchyma4 ,,vessels ,vessels and tracheids form the principal upward conducting tissue of plants4 ,they receive the soil water expressed from the cortical parenchyma cells located in the region of the root1 immediately back of the root hair zone4 ,this soil water1 with dissolved crude inorganic and organic food materials1 after entering the vessels and tracheids passes up the stem4 ,the cells needing water at the different heights absorb it from the vessels1 the excess finally reaching the leaves4 ,when the stem branches1 the water passes into the vessels of the branches and finally to the leaves of the branch4 ,in certain special cases the vessels conduct upward soluble food material4 ,in spring sugary sap flows upward through the vessels of the sugar maple4 ,vessels are tubes1 often of great length1 formed from a number of superimposed cells1 in which the end walls have become absorbed4 ,the vessels therefore offer little resistance to the transference of water from the roots to the leaves of a plant4 ,the combined length of the vessels is about equal to the height of the plant in which they occur4 ,the length of the individual vessels varies from a fraction of a meter up to several meters4 ,,annular ,,vessels ,the annular vessels are thickened at intervals in the form of rings 7,plate #dj1 ,fig4 #a71 which extend outward from and around the inner wall of the vessel4 ,in fact1 it is the inner wall which is thickened in all the different types of vessels4 ,the ring-like thickening usually separates from the wall when the drug is powdered4 ,such separated rings occur frequently in powdered digitalis1 belladonna1 and stramonium leaves4 ,annular vessels are not1 however1 of diagnostic importance1 because more characteristic cells are found in the plants in which they occur4 ,not infrequently a vessel will have annular thickenings at one end and spiral thickenings at the other4 ,such vessels are found in the pumpkin stem 7,plate #dj1 ,fig4 #a74 ,vessels are distinguished from other cells by their arrangement1 by their large size when seen in cross-section1 and by the thickening of the wall when seen in longitudinal sections of the plant or in powders4 ,the side walls of vessels are thickened in a number of striking yet uniform ways4 ,the chief types of thickening of the wall1 beginning with one that is the least thickened1 are annular1 spiral1 sclariform1 pitted1 and pitted with bordered pores4 ,,spiral ,,vessels ,in the spiral vessel the thickening occurs in the form of a spiral1 which is readily separated from the side walls4 ,this is particularly the case in powdered drugs1 where the spiral thickening so frequently separates from the cell wall4 ,there are three types of spiral vessels3 those with one 7,plate #da1 ,fig4 #a71 those with two1 and those with three spirals4 ,single spirals occur in most leaves2 double spirals occur in many plants 7,plate #da1 ,fig4 #b71 but they are particularly striking in powdered squills4 ,triple spirals are characteristic of the eucalyptus leaf 7,plate #da1 ,fig4 #c72 in fact1 they form a diagnostic feature of the powder4 ,frequently a spirally thickened wall indicates a developmental stage of the vessel4 ,many such vessels are spirally thickened at first1 but later1 when mature1 an increased amount of thickening occurs and the vessel becomes a reticulate or pitted vessel4 ,many mature vessels1 however1 are spirally thickened as indicated above4 ,in herbaceous stems and in certain roots and leaves spiral vessels are associated with the sclariform reticulate and pitted type4 ,in certain cases a single spiral band will branch as the vessel matures4 ,there is a great variation in the amount of spiral thickening occurring in a vessel4 ,in leaves1 particularly1 the spiral appears loosely coiled2 while in squills and other rhizomes and roots the spiral appears as a series of rings4 ,when viewed by high power only half of each spiral band is visible4 ,at either side of the cell the exact size and form of the thickening appear in two parallel rows of dark circles or projections from the walls4 ,this thickening of the wall is rendered visible from the fact that the light is retarded as it passes through that portion of the spiral extending from the upper to the under side of the spiral2 while the light readily traverses the upper and lower cross bands of the vessel4 ,it should be remembered that1 when the upper part of the spiral vessel is in focus1 the bands appear to bend in a direction away from the eye2 while when the under side of the bands are in focus1 the bands appear to bend toward the eye4 ,these facts will show that it is necessary to focus on both the upper and lower walls in studying spiral vessels4 ,in double spiral vessels the spirals are frequently coiled in opposite directions2 therefore the bands appear to cross one another4 ,in eucalyptus leaf the three bands are coiled in the same direction4 ,in all cases the thickening occurs on all sides of the wall4 ,its appearance will1 therefore1 be the same no matter at what angle the vessel is viewed4 ,,sclariform ,,vessels ,sclariform vessels have interrupted bands of thickening on the inner walls4 ,two or more such bands occur between the two side walls4 ,the series of bands are separated by uniformly thickened portions of the wall extending parallel to the length of the vessel4 ,sclariform vessels are usually quite broad1 so that it is necessary to change the focus several times in order to bring the different series of bands in focus4 ,the series of bands are usually of unequal width and length4 ,illustration3 ,,plate #dj ,,annular ,,and ,,spiral ,,vessels #a4 ,pumpkin stem 7,cucurbita pepo1 ,l474 #b4 ,two characteristic views of spiral vessels4 #c4 7,a7 ,upper part of spiral vessel in focus4 7,b7 ,under part of spiral vessel in focus4 #d4 ,spiral vessel of the disk petal matricaria 7,matricaria chamomilla1 ,l474 ,illustration3 ,,plate #da ,,spiral ,,vessels #a4 ,single spiral vessel of pumpkin stem 7,cucurbita pepo1 ,l474 #b4 ,double spiral vessel of squill bulb 7,urginea maritima1 ,l4 ,baker74 #c4 ,triple spiral vessel of eucalyptus leaf 7,eucalyptus globulus1 ,labill74 ,sclariform vessels occur in male fern 7,plate #db1 ,fig4 #b71 calamus1 tonga root 7,plate #db1 ,fig4 #c71 and sarsaparilla 7,plate #db1 ,fig4 #a74 ,in each they are characteristic4 ,sclariform vessels1 with these few exceptions1 do not occur in drug plants4 ,in fact1 drugs derived from dicotyledones rarely have sclariform vessels4 ,they occur chiefly in the ferns and drugs derived from monocotyledenous plants4 ,their presence or absence should1 therefore1 be noted when studying powdered drugs4 ,,reticulate ,,vessels ,reticulate vessels are of common occurrence in medicinal plants4 ,in fact1 they occur more frequently than any other type of vessel4 ,the basic structure of reticulate vessels 7,plate #dc1 ,fig4 #a7 occurring in different plants is similar1 but they vary in a recognizable way in different plants 7,plate #dc1 ,fig4 #b74 ,the walls of reticulate vessels are thickened to a greater extent than are the walls of spirally thickened vessels4 ,,pitted ,,vessels ,pitted vessels are met with most frequently in woods and wood-stemmed herbs4 ,there are two distinct types of pitted vessels--i4e41 simple pitted vessels and pitted vessels with bordered pores4 ,the pitted vessel represents the highest type of cell-wall thickening4 ,the entire wall of the vessel is thickened1 with the exception of the places where the pits occur4 ,the number and size of the pits vary greatly in different drugs4 ,in quassia 7,plate #dd1 ,fig4 #a7 the pits are numerous and very small1 and the openings are nearly circular in outline4 ,in white sandalwood 7,plate #dd1 ,fig4 #c74 the pits are few in number1 but when they do occur they are much larger than are the pits of quassia4 ,,pitted ,,vessels ,,with ,,bordered ,,pores ,pitted vessels with bordered pores are of common occurrence in the woody stems and stems of many herbaceous plants 7,plate #de1 ,figs4 #c and #d74 ,in such vessels the wall is unthickened for a short distance around the pits4 ,this unthickened portion may be either circular or angled in outline1 a given form being constant to the plant in which it occurs4 ,the pits vary from oval to circular4 ,pitted vessels with bordered pores occur in belladonna and aconite stems4 ,illustration3 ,,plate #db ,,sclariform ,,vessels #a4 ,sarsaparilla root 7,smilax officinalis1 ,kunth74 #b4 ,male fern 7,dryopteris marginalis1 ,l4 ,a4 ,gray74 #c4 ,tonga root4 ,illustration3 ,,plate #dc ,,reticulate ,,vessels #a4 ,hydrastis rhizome 7,hydrastis canadensis1 ,l474 #b4 ,musk root 7,ferula sumbul1 ,kauffm4 ,hook41 f474 ,illustration3 ,,plate #dd ,,pitted ,,vessels #a4 ,quassia1 low magnification 7,picrna excelsa1 ,swartz ,lindl474 #b4 ,quassia1 high magnification4 #c4 ,white sandalwood 7,santalum album1 ,l474 ,illustration3 ,,plate #de ,,vessels #a4 ,reticulate vessel of calumba root 7,jateorhiza palmata1 ,lam4 ,miers74 #b4 ,reticulate tracheid of hydrastis rhizome 7,hydrastis canadensis1 ,l474 #c4 ,pitted vessel with bordered pores of belladonna stem4 #d4 ,pitted vessel with bordered pores of aconite stem 7,aconitum napellus1 ,l474 ,vessels and tracheids lose their living-cell contents when fully developed4 ,in the vessels the cell contents disappear at the period of dissolution of the cell wall4 ,the walls of vessels and tracheids are composed of lignin1 a substance which prevents the collapsing of the walls when the surrounding cells press upon them1 and which also prevents the tearing apart of the wall when the vessel is filled with ascending liquids under great pressure4 ,lignin thus enables the vessel to resist successively compression and tearing forces4 ,tracheids are formed from superimposed cells with oblique perforated end walls4 ,the side walls of tracheids are thickened in a manner similar to those of vessels4 ,the tracheids in golden seal are of a bright-yellow color1 and groups of these short tracheids scattered throughout the field form the most characteristic part of the powdered drug4 ,in ipecac root the tracheids are of a porcelain-white1 translucent appearance1 and they are much longer than are the tracheids of golden seal4 ,the cellulose walls of parenchyma cells are stained blue with hmatoxylin and by chlorzinciodide4 ,cellulose is completely soluble in a fresh copper ammonia solution4 ,,sieve ,,tubes ,sieve tubes are downward-conducting cells4 ,they conduct downward proteid food material4 ,this fact is easily demonstrated by adding iodine to a section containing sieve tubes1 in which case the sieve tubes are turned yellow4 ,developing sieve tubes have all the parts common to a living cell2 but when fully mature1 however1 the nucleus becomes disorganized1 but a layer of protoplasm continues to line the cell wall4 ,sieve tubes 7,plate #df1 ,fig4 #a7 are composed of a great number of superimposed cells with perforated end walls and with non-porous cellulose side walls4 ,the end walls of two adjoining cells are greatly thickened and the pores pass through both walls4 ,this thickened part of the porous end walls of two sieve cells is called the sieve plate1 and it may be placed in an oblique or a horizontal position4 ,illustration3 ,,plate #df #a4 ,longitudinal section of sieve tube 7,cucurbita pepo1 ,l474 #b4 ,cross-section of sieve tube just above an end wall--sieve plate4 ,in a longitudinal section the sieve tubes are seen to be slightly bulging at the sieve plate1 and through the pores extend protoplasmic strands4 ,the strands are united on the upper and lower side of the sieve plate to form the protoplasmic strands of the living sieve tubes and the callus1 layers of dried plants4 ,this callus is frequently yellowish in color1 and in all cases is separated from the cell wall4 ,in certain plants the sieve plate occurs on the side walls of the sieve tubes in contact with other sieve tubes4 ,,sieve ,,plate ,sieve plates on cross-section 7,plate #df1 ,fig4 #b7 are polygonal in outline1 and the pores are either round or angled4 ,large sieve tubes and sieve plates occur in pumpkin stem2 but1 almost without exception1 in drug plants the sieve tubes are small and the sieve plate is inconspicuous4 ,when the drug is powdered1 the sieve tubes break up into undiagnostic fragments4 ,when studying sections of the plants1 the extent1 size1 and arrangement of the sieve tubes must always be noted4 ,,medullary ,,bundles1 ,,rays1 ,,and ,,cells ,function ,the medullary ray cells are the lateral conducting cells of the plant4 ,they conduct outwardly the water and inorganic salts brought up from the roots by the vessels and tracheids2 and they conduct inwardly toward the centre of the stem the food material manufactured in the leaves and brought down by the sieve cells4 ,the medullary rays thus distribute the inorganic and organic food to the living cells of the plant1 and they conduct the reserve food material to the storage cells1 and1 lastly1 they function in certain plants as storage cells4 ,occurrence ,the form1 size1 wall structure1 and the distribution of the medullary ray bundles1 rays1 and cells are best ascertained by studying3 first1 the cross-section of the plant2 secondly1 the radial section2 and1 thirdly1 the tangential section4 ,students should be careful to distinguish between the medullary ray bundle1 the medullary ray1 and the medullary ray cell4 ,in some plants the bundles are only one cell wide1 but in other plants the medullary ray bundle is more than one cell wide1 frequently several cells wide4 ,,the ,,medullary ,,ray ,,bundle ,the medullary ray bundle is made up of a great many medullary ray cells4 ,these bundles 7,plate #ajf1 ,fig4 #e7 are of variable length1 height1 and width4 ,the bundles are isolated1 and they occur among and separate the other cells of the plants in which they occur4 ,tangential sections show the medullary ray bundle in cross-section4 ,such sections are lens-shaped1 and they show both the width and the height of the medullary ray bundle4 ,the length of the medullary ray bundle is shown in cross-sections4 ,,the ,,medullary ,,ray ,the medullary ray 7,plate #dg7 is a term used to indicate that part of a medullary ray bundle which is seen in cross-sections and in radial sections4 ,in cross-sections the length of the ray will be as great as the length of the bundle1 and the width of the ray will be as great as the width of the medullary ray bundle at the point cut across4 ,in longitudinal sections the medullary ray will differ in height according to the thickness of the bundle at the point cut4 ,when the medullary rays extend from the centre of the stem to the middle bark1 they are termed primary medullary rays2 when they extend from the cambium circle to the middle bark1 they are termed secondary medullary rays4 ,as the plant grows1 the diameter of the organ becomes greater and the number of medullary rays are increased4 ,in each of these cases the medullary rays may be one or more than one cell wide1 according to whether the medullary ray bundle is one or more than one cell wide4 ,even in the same plant the width of the medullary rays will vary if the bundle is more than one cell wide1 according to width of the medullary ray bundle at the point cut across4 ,illustration3 ,,plate #dg ,,radial ,,longitudinal ,,section ,,of ,,white ,,sandalwood 7,santalum album1 ,l47 #a4 ,medullary ray4 #b4 ,wood fibres and wood parenchyma4 ,on cross-section the medullary rays are seen to vary greatly4 ,in many plants they are more or less straight radial lines1 as in quassia 7,plate #aje1 ,fig4 #b72 while in other plants they form wavy lines where they bend or curve around the conducting cells1 as in piper methysticum1 kava-kava 7,plate #dh1 ,fig4 ,a74 ,in the study of powdered drugs the radial view of the medullary rays is most frequently seen4 ,in a perfect radial section 7,plate #ajg1 ,fig4 #b7 the medullary rays are seen as tiers of cells in contact throughout their long diameter1 and they run at right angles to the long diameter of the other cells4 ,this view of the rays shows the length and height of the medullary ray4 ,in logwood the rays are often forty cells high4 ,in powdered barks1 woods 7,plate #dg71 and woody roots the radial view of the medullary rays is frequently diagnostic4 ,in guaiacum officianale wood the medullary rays are one cell wide on cross-section1 and up to six cells high on the tangential section4 ,in santalum album the rays are from one to three cells wide on cross-section1 and up to six cells high on tangential section4 ,in the greater number of plants the rays are more than one cell wide4 ,,the ,,medullary ,,ray ,,cell ,the medullary ray cell 7,plate #dh1 ,fig4 #a7 is one of the individual cells making up the medullary ray bundle and the medullary ray4 ,the cross-sections of the cells which are seen in tangential sections show the cells to be mostly circular in outline when they occur in the central portion of medullary ray bundles of more than two cells in width2 but they are more irregular in outline when the medullary ray bundle is only one cell wide4 ,even the cells of the three or more cell-wide bundles have irregular1 outlined cells at the ends of the bundle and on the sides in contact with the other tissues4 ,the length and height of the medullary ray cell are shown in radial sections2 while the width and length of the medullary ray cells are shown in cross-sections4 ,structure of ,cells ,the structure of the individual cells forming the medullary rays differs greatly in different plants1 but is more or less constant in structure in a given species4 ,the medullary rays of the wood usually have strongly pitted side and end walls1 while the medullary rays of most barks are not at all1 or only slightly1 pitted4 ,in most plants the cells are of nearly uniform size4 ,frequently1 however1 the cells vary in size in a given ray1 as shown in the cross-section of kava-kava4 ,arrangement of the ,cells in a ,ray ,the union of any two cells in a ray is also of importance4 ,in quassia the medullary ray cells have oblique end walls1 so that on cross-section the line of union between two cells is an oblique wall4 ,in most plants the medullary ray cells have blunt or square or oblique end walls1 so that the line of union is a straight line4 ,in most plants the cells are much longer than broad1 but the cells of sassafras bark are nearly as broad as long4 ,the walls of the cortical medullary ray cells and the medullary rays of most roots and stems of herbs are composed of cellulose2 while the walls of medullary ray cells occurring in woods are frequently lignified4 ,there is a great variation in the character of the cell contents of medullary rays4 ,in white pine bark 7,plate #dh1 ,fig4 ,b#a7 are deposits of tannin2 in quassia wood1 starch2 in canella alba1 rosette crystals of calcium oxalate1 etc4 ,,latex ,,tubes ,living latex tubes1 like sieve tubes1 have a layer of protoplasm lining the walls1 and1 in addition1 have numerous nuclei4 ,in drug plants the nuclei are not distinguishable1 but the protoplasm is always clearly discernible4 ,illustration3 ,,plate #dh ,a4 ,cross-section of kava-kava root 7,piper methysticum1 ,forst41 f474 #a4 ,unequal diameter medullary ray cells4 #b4 ,vessels4 #c4 ,wood parenchyma4 #d4 ,wood fibres4 ,b4 ,cross-section of white pine bark 7,pinus strobus1 ,l474 #a4 ,wavy medullary rays with tannin4 #b4 ,parenchyma cells4 #c4 ,sieve cells4 ,latex tubes function both as storage and as conducting cells4 ,they1 like the sieve tubes1 contain proteid substances chiefly1 yet frequently starch is found4 ,the cells bordering the latex tubes absorb from them1 as needed1 the soluble food material4 ,while our knowledge concerning the function of latex in some plants is meagre1 still in other plants it is practically certain that the latex is composed of nutritive substances which are utilized by the plant as food4 ,in certain other plants the latex appears to be used as a means of resisting insect attacks and as a protection against injury4 ,there are two types of latex tubes common to plants1 namely1 latex cells and latex vessels4 ,latex tubes developing from a single cell do not differ materially from a latex tube originating from the fusion of several cells4 ,in each case the latex tube branches to such an extent that it bears no resemblance to ordinary cells4 ,it would seem that the ultimate branches are formed and develop in much the same manner as root hairs--that is1 by a growing tip of the branch4 ,a mature plant may therefore have latex tubes with almost numberless branches 7,plate #ej1 ,fig4 #a7 and be of very great length4 ,the branches of latex tubes develop in such an irregular manner that it is possible to obtain a cross and a longitudinal section of the latex tubes by making a cross-section of stem4 ,such a section is shown in the drawing of the cross-section of the rhizome of black ,indian hemp 7,plate #di1 ,fig4 ,b74 ,the color of the latex in medicinal plants varies from a gray white in papaw 7carica papaya71 aromatic sumac1 black ,indian hemp1 and bitter root1 to white in the opium poppy1 light orange in celandine1 and deep orange in bloodroot 7,plate #ej1 ,fig4 #b74 ,in each of these cases it is the latex which yields the important medicinal products4 ,,parenchyma ,the larger amount of plant tissue is composed of parenchyma cells4 ,these cells vary from square to oblong1 or they may be irregular and branched4 ,the end walls are square or blunt1 and the wall is composed of cellulose1 with the exception of the wood parenchyma1 which has lignified walls4 ,there are seven characteristic types of parenchyma cells3 7#a7 cortical parenchyma1 7#b7 pith parenchyma1 7#c7 wood parenchyma1 7#d7 leaf parenchyma1 7#e7 aquatic plant parenchyma1 7#f7 endosperm parenchyma1 7#g7 phloem parenchyma4 ,illustration3 ,,plate #di ,a4 ,cross-section of black ,indian hemp 7,apocynum cannabinum1 ,l474 #a4 ,longitudinal section of a latex tube4 #b4 ,cross-section of latex tube4 #c4 ,parenchyma4 ,b4 ,cross-section of a part of black ,indian hemp root4 #d4 ,cross-section of a large latex tube4 #e4 ,parenchyma4 ,illustration3 ,,plate #ej ,,latex ,,vessels #a4 ,radial-longitudinal section of dandelion root 7,taraxacum officinale1 ,weber74 #b4 ,cross-section of sanguinaria root 7,sanguinaria canadensis1 ,l474 #c4 ,cross-section of dandelion root4 ,parenchyma cells1 cortical1 pith1 aquatic plant1 leaf1 flower1 and endosperm1 conduct in all directions--upward1 downward1 and laterally4 ,the direction of conduction depends upon the needs of the different cells forming the plant4 ,the fluids pass from the cell with an abundance of cell sap to the cell with less cell sap4 ,in this wall all cells are provided with food4 ,parenchyma cells conduct water absorbed by the roots and soluble carbohydrate material chiefly4 ,the walls of all the different types of parenchyma cells are composed of cellulose with the exception of the wood parenchyma cells1 the walls of which are lignified4 ,the end walls of non-branched parenchyma cells and the cell terminations of branched cells are very blunt4 ,,cortical ,,parenchyma ,cortical parenchyma 7,plate #ea7 differs greatly in size1 thickness of the walls1 and arrangement4 ,a study of the longitudinal sections of different parts of medicinal plants reveals the fact that the cortical parenchyma cells form superimposed layers in which the end walls are either parallel1 in which case the arrangement resembles that of several rows of boxes standing on end1 or the end walls of the cells alternate with each other1 in which case the arrangement is similar to that of the arrangement of the bricks in a building4 ,in certain plants the cortical parenchyma cells are long and narrow and rectangular in shape1 while in other plants the cells1 although still rectangular in outline1 are very broad and approach the square form4 ,all typical cortical parenchyma cells have uniformly thickened non-pitted walls4 ,in most barks the parenchyma cells beneath the bark are elongated tangentially1 but are very narrow radially4 ,the cells are always arranged around intercellular spaces1 which vary from triangular1 quadrangular1 etc41 according to the number of cells bordering the intercellular space4 ,,pith ,,parenchyma ,pith parenchyma 7,plate #eb7 differs from cortical parenchyma cells chiefly in the character of the walls1 which are usually thicker and always pitted4 ,illustration3 ,,plate #ea ,,parenchyma ,,cells #a4 ,longitudinal section of the cortical parenchyma of celandine root 7,chelidonium majus1 ,l47 #b4 ,cross-section of the cortical parenchyma of sarsaparilla root 7,smilax officinalis1 ,kunth74 ,illustration3 ,,plate #eb ,a4 ,longitudinal section of the pith parenchyma of grindelia stem 7,grindelia squarrosa1 ,pursh ,dunal74 #a4 ,cell cavity4 #b4 ,cross-section of the porous end wall4 #c4 ,surface view of the porous side wall4 ,b4 ,cross-section of the pith parenchyma of grindelia stem4 #a4 ,cell cavity4 #b4 ,porous walls4 #c4 ,pitted end walls4 ,,leaf ,,parenchyma ,the parenchyma cells 7,plate #aji1 ,fig4 #a7 of leaves1 of flower petals1 and the parenchyma cells of some aquatic plants are branched2 that is1 each cell has more than two cell terminations4 ,these cell terminations are frequently quite attenuated and usually very blunt4 ,such a cell structure provides for a greater amount of intercellular space and a maximum exposure of surface4 ,this arrangement makes it possible for the parenchyma cells of the leaf to absorb more readily the enormous amount of carbon dioxide needed in the photosynthetic process4 ,,aquatic ,,plant ,,parenchyma ,the parenchyma of aquatic plants 7,plate #ei7 has large intercellular spaces formed by the chains of cells4 ,,wood ,,parenchyma ,wood parenchyma 7,plate #aje1 ,fig4 #c7 cells are the narrowest parenchyma cells occurring in the plant4 ,their walls are always lignified and strongly pitted1 and in some cases the end walls common to two cells are obliquely placed4 ,,phloem ,,parenchyma ,phloem parenchyma 7,plate #ajj1 ,fig4 #h7 cells are usually associated with sieve cells4 ,they are very long1 narrow1 and have thin1 non-pitted walls4 ,the thinness of the walls undoubtedly enables the cells to conduct diffusible food substance more quickly than the cortical parenchyma cells4 ,,palisade ,,parenchyma ,palisade parenchyma of leaves is of the typical parenchyma shape and the end walls are placed nearly on a plane1 even when more than one layer is present4 ,the cells are very small1 however1 and the walls are very thin and non-pitted4 ,,chapter ,,vi ,,aerating ,,tissue ,the aerating tissue of the plant performs a threefold function3 first1 it permits the exchange of gases during photosynthesis2 secondly1 it permits the entrance of oxygen and the exit of carbon dioxide during respiration2 and1 thirdly1 it permits the exit of the excess of water absorbed by the plant4 ,the above functions are carried on by the stomata1 the water-pores1 the lenticels1 and the intercellular spaces of the plant4 ,the stoma functions as the chief channel for the passage of ,,co-laden air into the leaf and of oxygen-laden air from the leaf to the atmosphere4 ,the stoma also functions as an organ of transpiration1 since through the stoma a large part of the excess water of the plant passes off into the air4 ,,water-,,pores ,in certain plants the primary epidermis is provided with openings resembling stomata1 but unlike stomata the orifice remains open1 and instead of being located on the upper or lower surface of the leaf1 they are located on the margin of leaves immediately outward from the veins4 ,water is given off to the atmosphere from these openings4 ,such an opening is usually designated as a water-pore4 ,,stomata ,the chief external openings of the epidermis of leaves1 of herbs1 and of young wood stems are known as stomata4 ,surrounding the stoma are two cells known as guard cells4 ,guard cells differ greatly in form1 in size1 in arrangement1 in occurrence1 in association1 in abundance 7,plates #ec1 #ed1 and #ee71 and in color4 ,the guard cells surrounding the stoma vary in form from circular to lens-shaped4 ,in most leaves the outline of the guard cells is rounded or has a curved outline2 but in a few cases the guard cells have angled outlines4 ,illustration3 ,,plate #ec #a4 ,stoma and surrounding cells of aconite stem 7,aconitum napellus1 ,l474 #b4 ,stoma and angled striated walled surrounding cells of peppermint stem 7,mentha piperita1 ,l474 #c4 ,stoma and elongated surrounding cells of lobelia stem 7,lobelia inflata1 ,l474 ,illustration3 ,,plate #ed ,,types ,,of ,,stoma #a4 ,under epidermis of short buchu 7,barosma betulina1 ,berg4 ,bartling and ,wendl41 f47 showing stoma and deposits of hesperidin4 #b4 ,under epidermis of ,alexandria senna 7,cassia acutifolia1 ,delile7 showing stoma and thick-angled walled surrounding cells4 #c4 ,upper epidermis of eucalyptus leaf 7,eucalyptus globulus1 ,labill47 showing sunken stoma and slightly beaded walled surrounding cells4 #d4 ,under epidermis of belladonna leaf 7,atropa belladonna1 ,l47 showing stoma and wavy1 striated1 walled epidermal cells4 ,the arrangement of the surrounding cells of the stoma is one of the most important characteristics of the different leaves4 ,as a rule the number of surrounding cells about a stoma is constant for a given species4 ,in senna leaves 7,plate #ed1 ,fig4 #b7 there are normally two surrounding cells about each guard cell1 while in coca there are four 7,plate #ee1 ,fig4 #a74 ,in senna the long diameter of the surrounding cells is parallel to the long diameter of the guard cells2 but in coca the long diameter of two surrounding cells is at right angles to the long diameter of the guard cells1 while two cells are parallel to the long diameter of the guard cells4 ,in most leaves there are more than two cells around the guard cells4 ,the form and size of the surrounding cells must always be considered4 ,in most leaves they are variable in size and form4 ,guard cells occur first1 even with the surface of the leaf 7,plate #ef1 ,fig4 ,a72 secondly1 above the surface of the leaf 7,plate #ef1 ,fig4 ,b72 and1 thirdly1 below the surface of the leaf4 7,plate #ef1 ,fig4 ,c74 ,only one of the above types occurs in a given species of plant4 ,that is1 plants with stomata above the surface of the leaf do not have stomata on a level with or below the leaf surface4 ,the number of stomata on a given surface of a different leaf varies considerably4 ,in many of the medicinal leaves stomata occur only on the under surface of the leaf4 ,in other leaves stomata occur on both surfaces of the leaf2 but in such cases there are a greater number on the under surface4 ,in certain leaves the long diameter of the guard cells is parallel to the length of the leaf2 in other cases the long diameter of the stoma is arranged at right angles to the length of the leaf4 ,in other leaves the arrangement is still more irregular1 the guard cells assuming all sorts of positions in relation to the length of the leaf4 ,illustration3 ,,plate #ee ,,leaf ,,epidermi ,,with ,,stoma #a4 ,under epidermis of coca leaf 7,erythroxylon coca1 ,lam47 with stoma on a level with the surface4 #b4 ,under epidermis of false buchu 7,marrubium peregrinum1 ,l47 with stoma below the level of the surface4 #c4 ,upper epidermis of deer tongue 7,trilisa odoratissima1 ,walt4 ,cass47 with stoma above the leaf surface4 ,illustration3 ,,plate #ef ,a4 ,cross-section of belladonna leaf 7,atropa belladonna1 ,l474 #a1 ,epidermal cells2 #b1 ,guard cells even with the leaf surface2 #c1 ,surrounding cells2 #d1 ,air space below the guard cells2 #e1 ,palisade cells2 #f1 ,mesophyll cells4 ,b4 ,cross-section of deer tongue leaf1 #a4 ,epidermal cells2 #b1 ,guard cells above the surface of the leaf2 #c1 ,surrounding cells2 #d1 ,air space below the guard cells2 #e1 ,hypodermal cells4 ,c4 ,cross-section of white pine leaf 7,pinus strobus1 ,l474 #a1 ,epidermal and hypodermal cells2 #b1 ,guard cells below the leaf surface2 #c1 ,surrounding cells2 #d1 ,air space below the guard cells2 #e1 ,parenchyma cells with projecting inner walls4 ,the relation of the stoma to surrounding cells is best shown in cross-sections of the leaf4 ,in powders the relationship of the stoma to the surrounding cells is1 however1 readily ascertained4 ,if the guard cells come in focus first1 they are above the surface2 if the guard cells and the surrounding cells come in focus at the same time1 the stomata are even with the surface2 if the stomata come in focus after the surrounding cells1 they are below the surface of the leaf4 ,the relationship of the stoma to the surrounding cells should always be ascertained1 not only in cross-sections of the leaf1 but also in powders4 ,there is the greatest possible variation in the size of guard cells4 ,this fact must always be kept in mind when studying leaves4 ,this variation in the size of the guard cells is clearly illustrated by coca1 senna1 and by deer's-tongue4 ,in coca the stomata are very small2 in senna they are larger2 while in deer's-tongue the stomata are very large4 ,the width and length of the stoma or opening between the guard cells are of a character which must not be overlooked4 ,generally speaking1 those leaves which have large guard cells will have correspondingly large stomata4 ,the guard cells usually contain chloroplasts showing various stages of decomposition4 ,in bay-rum leaf the guard cells are of a bright reddish-brown color1 but in most leaves the guard cells are colorless4 ,,lenticels ,lenticels are small openings occurring in the bark of plants4 ,the lenticels bear the same relationship to the stem that the stomata do to the leaves4 ,lenticels1 like stomata1 have a threefold function--namely1 exchange of gases in photosynthesis1 in respiration1 and the giving off of water4 ,lenticels are macroscopically as well as microscopically important4 ,when unmagnified the lenticels are circular1 lens-shaped1 or irregular in outline4 ,they are arranged in parallel longitudinal lines or parallel transverse lines1 or they are irregularly scattered4 ,the latter is the usual arrangement4 ,in most cases they are elevated slightly above the surface of the bark4 ,in root barks particularly the lenticels stand out prominently from the surface of the bark and in many cases appear stalked4 ,the color of the lenticels differs greatly in the different plants4 ,in acer spicatium they are brown2 in witch-hazel they are gray2 in xanthoxylium they are yellowish2 and lastly1 the number of lenticels occurring in a given surface of the bark should always be considered4 ,on cross-sections the lenticel 7,plate #eg1 ,fig4 #b7 is seen to have a central depressed portion made up of loosely arranged cells4 ,bordering the cavity are typical cork cells4 ,the cork cells immediately surrounding the lenticels are usually darker in color1 and many of the cells are partly broken down4 ,the size of lenticels will vary according to the type of the lenticel4 ,in studying sections more attention should be paid to the character of the cells forming the lenticels than to the size of the lenticel4 ,on cross-section the intercellular spaces 7,plate #eh7 are triangular1 quadrangular1 or irregular4 ,the spaces between equal diameter parenchyma cells is triangular if three cells surround the space1 and quadrangular if four cells surround the space1 etc4 ,these spaces are in direct contact with similar spaces that traverse the tissue at right angles to its long axis4 ,the branched mesophyll cells of the leaf and aquatic plant parenchyma 7,plate #ei7 are arranged around irregular cavities4 ,in leaves and aquatic plants these spaces run parallel to the long axis of the organ4 ,in each of the above cases the cavity is formed by the separation of the cell walls4 ,there is still another type of irregular cavities which is formed by the dissolution or tearing apart of the cell walls4 ,such cavities are found in the stems and roots of many herbs4 ,the pith cells in the stems of many herbs become torn apart during the growth of the stem1 with the result that large irregular cavities are formed4 ,these cavities are usually filled with circulatory air4 ,in the stems of conium1 cicuta1 angelica1 and other larger herbaceous stems the pith separates into layers4 ,when a longitudinal section is made of such a stem it is seen to be composed of alternating air spaces and masses of pith parenchyma4 ,the intercellular spaces are very large in leaves where enormous quantities of carbon dioxide are vitalized in photosynthesis4 ,illustration3 ,,plate #eg ,,cross-,,section ,,of ,,elder ,,bark 7,sambucus canadensis1 ,l474 #a4 ,periderm4 #b4 ,lenticel4 #c4 ,phellogen4 ,illustration3 ,,plate #eh ,,intercellular ,,air ,,spaces ,a4 ,cross-section of uva-ursi leaf 7,arctostaphylos uva-ursi1 ,l4 ,spreng474 #a4 ,irregular intercellular air spaces4 ,b4 ,cross-section of the cortical parenchyma of sarsaparilla root 7,smilax officinalis1 ,kunth74 #a1 ,triangular intercellular spaces2 #b1 ,quadrangular intercellular air spaces2 #c1 ,pentagular intercellular air spaces4 ,illustration3 ,,plate #ei ,,irregular ,,intercellular ,,air ,,spaces #a4 ,skunk-cabbage 7,symplocarpus ftidus1 ,l4 ,nutt47 #b4 ,calamus rhizome 7,acorus calamus1 ,l474 ,in the rhizome of calamus and other aquatic plants the intercellular spaces are very large4 ,the cells of these plants are arranged in the form of branching chains of cells which thus provide for large intercellular spaces4 ,the cells of the middle layer of flower petals1 like the mesophyll of leaves1 is loosely arranged owing to the peculiar branching form of the cells4 ,seeds and fruits contain1 as a rule1 few or no intercellular spaces4 ,,chapter ,,vii ,,synthetic ,,tissue ,under synthetic tissue are grouped all tissues and cells which form substances or compounds other than protoplasm4 ,such compounds are stored either in special cavities or in the cells of the plant1 as the glandular hairs2 internal secreting cavities of barks1 stems1 leaves1 fruits1 seeds1 and flowers2 photosynthetic cells or cells with chlorophyll1 and the parenchymatic cells which form starch1 sugar1 fats1 alkaloids1 etc4 ,,photosynthetic ,,tissue ,the most important non-glandular synthetic tissue is the photosynthetic tissue1 which is composed of the chlorophyll-bearing cells of the plant4 ,these are the so-called green cells of leaves1 of stems of herbs1 of young woody stems1 and in the older woody stems of plants like wild cherry1 birch1 etc4 ,the greater part of the tissue of leaves is composed of chlorophyll-bearing cells4 ,leaves collectively constitute the greatest synthetic manufacturing plant in the world1 because the green cells of the leaf produce most of the food of men and animals4 ,the two compounds utilized in the manufacture of food are carbon dioxide 7,,co7 and water 7,h,o74 ,these two compounds are combined by chlorophyll through the agency of light into starch4 ,chemically this reaction may be expressed as follows3 #f;,,co #e;,h,o #b;,c,h,o #f,o4 ,during the day a large quantity of starch is formed4 ,at night through the action of a ferment the excess of starch remaining in the leaf is converted into sugar 7,c,h,o7 - ,c,h,o ,h,o ,c,h,o4 ,in this form it is distributed to the living cells of the plant4 ,the presence or absence of starch in leaves is easily ascertained by placing the leaf in hot alcohol to remove the chlorophyll1 and by adding ,lugol's solution4 ,if starch is present1 the contents of the cells will become bluish black2 but if no starch is present1 the cells remain colorless4 ,,glandular ,,tissue ,the glandular tissue of the plant is divided into two groups1 according to where it occurs4 ,these groups are1 first1 external glandular tissue1 and secondly1 internal glandular tissue4 ,the most important external glandular tissue is composed of the glandular hairs4 ,these are divided into two groups3 first1 unicellular2 and secondly1 multicellular glandular hairs4 ,,unicellular ,,glandular ,,hairs ,the unicellular glandular hairs are either sessile or stalked4 ,sessile unicellular hairs occur in digitalis leaves4 ,stalked unicellular hairs of digitalis are shown on ,plate #fj1 ,fig4 #b4 ,unicellular uniseriate stalked glandular hairs occur on the stems of the common house geranium 7,plate #fa1 ,fig4 #b71 on the leaves of butternut1 the leaves and stems of marrubium peregrinum 7,plate #ih1 ,fig4 #e71 and in arnica flowers4 ,the stalk varies from two to ten cells2 in eriodictyon the cells vary from four to eight cells4 ,unicellular multiseriate stalked glandular hairs are not of common occurrence4 ,,multicellular ,,glandular ,,hairs ,multicellular glandular hairs are divided into two groups3 first1 sessile2 and secondly1 stalked hairs4 ,multicellular sessile glandular hairs occur on the leaves of peppermint 7,plate #fj1 ,fig4 #c71 horehound 7,plate #ig1 ,fig4 #g71 and in hops 7,plate #fj1 ,fig4 #d74 ,in each of these hairs there are eight secretion cells4 ,stalked glandular hairs are divided into two groups3 first1 uniseriate stalked2 and secondly1 multiseriate stalked glandular hairs4 ,multicellular uniseriate stalked glandular hairs occur on the leaves of tobacco 7,plate #fa1 ,fig4 #d71 belladonna 7,plate #fa1 ,fig4 #a71 and digitalis 7,plate #fj1 ,fig4 #b71 and of the fruit of rhus glabra4 ,illustration3 ,,plate #fj ,,glandular ,,hairs #a4 ,kamala 7,mallotus philippinensis1 ,lam4 ,muell4 ,arg474 #b4 ,digitalis leaf 7,digitalis purpurea1 ,l474 #c4 ,peppermint leaf 7,mentha piperita1 ,l474 #d4 ,lupulin4 #e4 ,cannabis indica leaf 7,cannabis saliva1 ,l474 ,multicellular multiseriate stalked glandular hairs occur on the stems and leaves of cannabis indica 7,plate #fj1 ,fig4 #e74 ,in the glandular hair of kamala 7,plate #fj1 ,fig4 #a7 the number of secretion cells is variable and papillate in form1 and the cuticle is separated from the secretion cells4 ,in the glandular hair of hops the outer wall or cuticle is torn away from the secretion cells1 and the cavity thus formed serves as a storage cavity4 ,this distended cuticle of the hops shows the outline of the cells from which it was separated4 ,in the glandular hairs of the mints the secreted products 7volatile oils7 are stored between the secretion cells and the outer detached cuticle4 ,this cuticle is elastic1 and it becomes greatly distended as the volatile oil increases in amount4 ,in many of the so-called glandular hairs1 tobacco1 belladonna geranium1 etc41 the synthetic products are retained in the glandular cells1 there being no special cavity for their storage4 ,these hairs usually contain an abundance of chlorophyll4 ,the division wall of multicellular glandular hairs may be vertical1 as in the two-celled hair of digitalis 7,plate #fj1 ,fig4 #b72 as in horehound 7,plate #ig1 ,fig4 #f71 and as in peppermint 7,plate #fj1 ,fig4 #c72 in this case there are eight cells1 and they form a more or less flat plate of cells4 ,in other hairs the division wall is horizontal2 this produces a chain of superimposed secreting cells1 as in some of the glandular hairs of belladonna leaf 7,plate #fa1 ,fig4 #a71 etc4 ,in other hairs the division walls are both vertical and horizontal1 as in tobacco 7,plate #fa1 ,fig4 #d71 henbane 7,plate #fa1 ,fig4 #c71 belladonna 7,plate #fa1 ,fig4 #a74 ,other characters to be kept in mind in studying glandular hairs are the following3 ,color of cell contents2 size of the cells1 whether uniform or variable2 character of wall1 whether smooth or rough4 ,,secretion ,,cavities ,secretion cavities are divided into three groups1 according to the nature of the origin of the cavity3 first1 schizogenous cavities1 which originate by a separation of the walls of the secretion cells2 secondly1 lysigenous cavities1 which arise by the dissolution of the walls of centrally located secretion cells2 and thirdly1 schizo-lysigenous cavities1 which originate schizogenously1 but later become lysigenous owing to the dissolution of the outer layers of the secretion cells4 ,illustration3 ,,plate #fa ,,stalked ,,glandular ,,hairs #a4 ,belladonna leaf 7,atropa belladonna1 ,l474 #b4 ,geranium stem 7,geranium maculatum1 ,l474 #c4 ,henbane leaf 7,hyoscyamus niger1 ,l474 #d4 ,tobacco leaf 7,nicotiana tabacum1 ,l474 ,,schizogenous ,,cavities ,schizogenous cavities occur in white pine bark 7,plate #fb1 ,fig4 ,b74 ,the cells lining the cavity are mostly tangentially elongated1 and the wall extends into the cavity in the form of a papillate projection4 ,immediately back from these cells are two or three layers of cells which resemble cortical parenchyma cells1 except that they are smaller and their walls are thinner4 ,in white pine bark there is a single layer of thin-walled cells lining the cavity4 ,immediately surrounding the secretion cells is a single layer of thick-walled fibrous cells4 ,in klip buchu 7,plate #fc1 ,fig4 ,b71 as in white pine leaf 7,plate #fd1 ,fig4 ,b71 there is a single layer of thin-walled secretion cells which are surrounded on three sides with parenchyma cells and on the outer side by epidermal cells4 ,,lysigenous ,,cavities ,lysigenous cavities occur on the rind of citrus fruits--bitter and sweet orange1 lemon1 grapefruit1 lime1 etc41 and in the leaves of garden rue1 etc4 ,in bitter orange peel1 7,plate #fd1 ,fig4 ,a7 the cavity is very large1 and the cells bordering the cavity are broken and partially dissolved4 ,the entire cells back of these are white1 thin-walled1 tangentially elongated cells4 ,there is a great variation in the size of these cavities1 the smaller cavities being the recently formed cavities4 ,,schizo-,,lysigenous ,,cavities ,schizo-lysigenous cavities are formed in white pine bark and many other plants owing to the increase in diameter of the stem4 ,in such cases the walls of the secreting cells break down4 ,the resulting cavity resembles lysigenous cavities4 ,unicellular secretion cavities occur in ginger1 aloe1 calamus1 and in canella alba barb4 ,illustration3 ,,plate #fb ,a4 ,cross-section of calamus rhizome 7,acorus calamus1 ,l474 #a1 ,intercellular space2 #b1 ,parenchyma cells2 #c1 ,secretion cavity4 ,b4 ,cross-section of white pine bark 7,pinus strobus1 ,l474 #a1 ,parenchyma2 #b1 ,secretion cavity2 #c1 ,secretion cells4 ,illustration3 ,,plate #fc ,a4 ,cross-section of a portion of canella alba bark 7,canella alba1 ,murr474 #a4 ,excretion cavity4 ,b4 ,cross-section of a portion of klip buchu leaf4 #a4 ,epidermal cells4 #b4 ,secretion cavity4 #c4 ,secretion cells4 ,illustration3 ,,plate #fd ,a4 ,cross-section of bitter orange peel 7,citrus aurantium1 amara1 ,l474 #a1 ,internal secretion cavity formed by the dissolution of the walls of the central secreting cells2 #b1 ,secretion cells4 ,b4 ,cross-section of white pine leaf 7,pinus strobus1 ,l474 #a1 ,epidermal and hypodermal cells2 #b1 ,parenchyma cells with protruding inner walls2 #c1 ,endodermis2 #d1 ,secretion cavity2 #e1 ,secretion cells4 ,in calamus 7,plate #fb1 ,fig4 ,a7 the cavity is larger than the surrounding cells2 it is rounded in outline1 and it contains oleoresin4 ,these cavities are in contact with the ordinary parenchyma cells1 from which they are easily distinguished by their larger size and rounded form4 ,the unicellular oil cavity of canella alba 7,plate #fc1 ,fig4 ,a7 is rounded or oval in cross-section and is many times larger than the surrounding cells4 ,the wall1 which is very thick1 is of a yellowish color4 ,secretion cavities vary greatly in form1 according to the part of the plant in which they are found4 ,in flower petals and leaves they are spherical2 in barks they are usually elliptical2 in umbelliferous fruits they are elongated and tube-like4 ,mucilage cavities are not of common occurrence in medicinal plants4 ,they occur1 however1 in the stem and root bark of sassafras1 the stem bark of slippery elm1 the root of althea1 etc4 ,,chapter ,,viii ,,storage ,,tissue ,most drug plants contain storage products because they are collected at a period of the year when the plant is storing1 or has stored1 reserve products4 ,these products are stored in a number of characteristic ways and in different types of tissue4 ,the most important of the different types of storage tissue that occurs in plants are the storage cells1 the storage cavities1 and the storage walls4 ,,storage ,,cells ,several different types of cells function as storage tissue4 ,these cells1 which are given in the order of their importance1 are parenchyma1 crystal cells1 medullary rays1 stone cells1 wood fibres1 bast fibres1 and epidermal and hypodermal cells4 ,,cortical ,,parenchyma ,cortical parenchyma of biennial rhizomes1 bulbs1 roots1 and the parenchyma of the endosperm of seeds store most of the reserve economic food products of the higher plants4 ,pith parenchyma of sarsaparilla root 7,plate #fe1 ,fig4 #d7 and the pith parenchyma of the rhizome of memspermun1 like the pith parenchyma of most plants1 function as storage cells4 ,,wood ,,parenchyma ,wood parenchyma1 particularly of the older wood1 function as storage tissue4 ,the wood parenchyma of quassia1 like the wood parenchyma of most woods1 contain stored products4 ,in some cases the wood parenchyma contain starch1 in others crystals1 and in others coloring matter1 etc4 ,illustration3 ,,plate #fe #a4 ,stone cells with starch of ,ceylon cinnamon 7,cinnamomum ceylanicum1 ,nees474 #b4 ,stone cells with solitary crystals of calumba root 7,jateorhiza palmata1 ,lam4 ,miers74 #c4 ,parenchyma cells1 with starch of cascarilla bark 7,croton eluteria1 ,l4 ,benn474 #d4 ,cortical parenchyma with starch of sarsaparilla root 7,smilax officinalis1 ,kunth74 #e4 ,cortical parenchyma1 with starch of leptandra rhizome 7,leptandra virginica1 ,l4 ,nutt474 #f4 ,crystal cells1 with solitary crystals of quebracho bark 7,schlechtendal74 #g4 ,bast fibre of blackberry root with starch 7,rubus cuneifolius1 ,pursh474 ,illustration3 ,,plate #ff ,,mucilage ,,and ,,resin #a4 ,cross-section of elm bark 7,ulmus fulva1 ,michaux7 showing two cavities filled with partially swollen mucilage4 #b4 ,mucilage mass from sassafras stem bark 7,sassafras variifolium1 ,l474 #c4 ,mucilage mass from elm bark4 #d4 ,resin mass from white pine bark 7,pinus strobus1 ,l474 ,in many plants1 however1 the parenchyma cells contain crystals4 ,the parenchyma cells of rhubarb contain rosette crystals1 while the parenchyma cells of the cortex of sarsaparilla and false unicorn root contain bundles of raphides4 ,in every case observed the raphides are surrounded by mucilage4 ,this is true of squills1 sarsaparilla1 false unicorn1 etc4 ,when cells with raphides and mucilage are mounted in a mixture of alcohol1 glycerine1 and water1 the mucilage first swells and finally disappears4 ,,storage ,,cavities ,particular attention should be given to storage cavities whenever they occur in plants1 for the reason that they are usually filled with storage products1 and for the added reason that storage cavities are not common to all plants4 ,storage cavities occur in roots1 stems1 leaves1 flowers1 fruits1 and seeds4 ,,crystal ,,cavities ,characteristic crystal cavities occur in many plants4 ,such a cavity containing a bundle of raphides is shown in the cross-section of skunk cabbage leaf 7,plate #fg74 ,,secretion ,,cavities ,in white pine bark there are a great number of secretion cavities which are partially or completely filled with oleoresin4 ,in the cross-sections of white pine bark the secretion cavities are very conspicuous1 and they vary greatly in size4 ,this variation is due1 first1 to the age of the cavity1 the more recently formed cavities being smaller2 and secondly1 to the nature of the section1 which will be longer in longitudinal section1 which will be through the length of the secretion cavity1 and shorter on transverse section4 ,such a section shows the width of the secretion cavity4 ,characteristic mucilage cavities occur in sassafras root1 stem bark1 elm bark 7,plate #ff1 ,fig4 #a71 marshmallow root1 etc4 ,these cavities form a conspicuous feature of the cross-section of these plants4 ,the presence or absence of mucilage cavities in a bark should be carefully noted4 ,,latex ,,cavities ,the latex tube cavities are characteristic in the plants in which they occur4 ,these cavities as explained under latex tubes are very irregular in outline4 ,illustration3 ,,plate #fg ,,cross-,,section ,,of ,,skunk-,,cabbage ,,leaf 7,symplocarpus ftidus1 ,l4 ,nutt47 #a4 ,crystal cavity4 #b4 ,bundle of raphides4 ,,oil ,,cavity ,canella alba contains an oil cavity resembling in form the mucilage cavity of elm bark4 ,secretion cavities occur in most of the umbelliferous fruits4 ,for each fruit there is a more or less constant number of cavities4 ,anise has twenty or more1 fennel usually has six cavities1 and parsley has six cavities4 ,in poison hemlock fruits there are no secretion cavities4 ,in certain cases1 however1 the number of secretion cavities can be made to vary4 ,this was proved by the author in the case of celery seed4 ,he found that cultivated celery seed1 from which stalks are grown1 contains six oil cavities 7,plate #abb1 ,fig4 #b71 while wild celery seed 7,plate #ajb1 ,fig4 #a71 grown for its medicinal value1 always contains more than six cavities4 ,most of the wild celery seeds contain twelve cavities4 ,many leaves contain cavities for storing secreted products4 ,such storage cavities occur in fragrant goldenrod1 buchu1 thyme1 savary1 etc4 ,the leaves in which such cavities occur are designated as pellucid-punctate leaves4 ,such leaves will1 when held between the eye and the source of light1 exhibit numerous rounded translucent spots1 or storage cavities4 ,,glandular ,,hairs ,the glandular hair of peppermint 7,plate #fj1 ,fig4 #c7 and other mints consists of eight secretion cells1 arranged around a central cavity and an outer wall which is free from the secretion cells4 ,this outer wall becomes greatly distended when the secretion cells are active1 and the space between the secretion cells and the wall serves as the storage place for the oil4 ,when the mints are collected and dried1 the oil remains in the storage cavity for a long time4 ,,stone ,,cells ,the stone cells of the different cinnamons 7,plate #fe1 ,fig4 #a7 store starch grains2 these grains often completely fill the stone cells4 ,the yellow stone cells of calumba root 7,plate #fe1 ,fig4 #b7 usually contain four prisms of calcium oxalate1 which may be nearly uniform or very unequal in size4 ,,bast ,,fibres ,the bast fibres of the different rubus species 7,plate #fe1 ,fig4 #g7 contain starch4 ,the medullary rays of quassia 7,plate #ajg1 ,fig4 #b7 contain starch2 while the medullary rays of canella alba contain rosette crystals4 ,in a cross-section of canella alba 7,plate #ha1 ,fig4 #c7 the crystals form parallel radiating lines which1 upon closer examination1 are seen to be medullary rays1 in each cell of which a crystal usually occurs4 ,the epidermal and hypodermal cells of leaves serve as water-storage tissue4 ,these cells usually appear empty in a section4 ,the barks of many plants--i4e41 quebracho1 witch-hazel1 cascara1 frangula1 the leaves of senna and coca1 and the root of licorice--contain numerous crystals4 ,these crystals occur in special storage cells--crystal cells 7,plate #fe1 ,fig4 #f7--which usually form a completely enveloping layer around the bast fibres4 ,these cells are usually the smallest cells of the plant in which they occur1 and with but few exceptions each cell contains but a single crystal4 ,the epidermal cells of senna leaves and the epidermal cells of mustard are filled with mucilage2 the walls even consist of mucilage4 ,such cells are always diagnostic in powders4 ,,storage ,,walls ,storage walls 7,plates #fh and #fi7 occur in colchicum seed1 saw palmetto seed1 areca nut1 nux vomica1 and ,saint ,ignatius's bean4 ,in each of these seeds the walls are strongly and characteristically thickened and pitted4 ,in no two plants are they alike1 and in each plant they are important diagnostic characters4 ,storage cell walls consist of reserve cellulose1 a form of cellulose which is rendered soluble by ferments1 and utilized as food during the growth of the seed4 ,reserve cellulose is hard1 bony1 and of a waxy lustre when dry4 ,upon boiling in water the walls swell and become soft4 ,the structure of the reserve cellulose varies greatly in the different seeds in which it occurs in the thickness of the walls and in the number and character of the pores4 ,illustration3 ,,plate #fh ,,reserve ,,cellulose #a4 ,saw palmetto 7,serenoa serrulata1 ,michaux ,hook41 f474 #b4 ,areca nut 7,areca catechu1 ,l474 #c4 ,colchicum seed 7,colchicum autumnale1 ,l474 #c-;,a4 ,porous side wall4 #c-;,b4 ,cell cavity above the side wall4 ,illustration3 ,,plate #fi ,,reserve ,,cellulose #a4 ,endosperm of nux vomica 7,strychnos nux vomica1 ,l474 #b4 ,endosperm of ,st4 ,ignatia bean 7,strychnos ignatii1 ,berg474 ,,chapter ,,ix ,,cell ,,contents ,the cell contents of the plant are divided into two groups3 first1 organic cell contents2 and secondly1 inorganic cell contents4 ,the organic cell contents include plastids1 starch grains1 mucilage1 inulin1 sugar1 hesperidin1 alkaloids1 glucocides1 tannin1 resin1 and oils4 ,,chlorophyll ,the chloroplasts of the higher plants are green1 and they vary somewhat in size1 but they have a similar structure and form4 ,chloroplasts are mostly oval in longitudinal view and rounded in cross-section view4 ,each chlorophyll grain has an extremely thin outer wall1 which encloses the protoplasmic substance1 the green granules1 a green pigment 7chlorophyll71 and a yellow pigment 7xanthophyll74 ,frequently the wall includes starch1 oil drops1 and protein crystals4 ,chloroplasts are arranged either in a regular peripheral manner along the walls1 or they are diffused throughout the protoplast4 ,the palisade cells of most leaves are packed with chlorophyll grains4 ,in the mesophyll cells the chlorophyll grains are not so numerous1 and they are arranged peripherally around the innermost part of the wall4 ,chloroplasts multiply by fission--that is1 each chloroplast divides into two equal halves1 each of which develops into a normal chloroplast4 ,chlorophyll occurs in the palisade1 spongy parenchyma1 and guard cells of the leaf2 in the collenchyma and parenchyma of the cortex of the stems of herbs and of young woody stems1 and1 under certain conditions1 in rhizomes and roots exposed to light4 ,almost without exception young seeds and fruits have chlorophyll4 ,in powdered leaves1 stems1 etc41 the chlorophyll grains occur in the cells as greenish1 more or less structureless masses4 ,yet cells with chlorophyll are readily distinguished from cells with other cell contents4 ,in witch-hazel leaf the chlorophyll grains appear brownish in color4 ,powdered leaves and herbs are readily distinguished from bark1 wood1 root1 and flower powders4 ,leaves and the stems of herbs are of a bright-green color4 ,with the exception of the guard cells1 the chloroplasts occur one or more layers below the epidermis2 but1 owing to the translucent nature of the outer walls of these cells1 the outer cells of leaves and stems appear green4 ,wild cherry1 sweet birch1 and1 in fact1 most trees with smooth barks have chloroplasts in several of the outer layers of the cortical parenchyma4 ,when the thin outer bark is removed from these plants1 the underlying layers are seen to be of a bright-green color4 ,,leucoplastids ,leucoplastids1 or colorless plastids1 occur in the underground portions of the plant2 they may1 when these organs in which they occur are exposed to light1 change to chloroplastids4 ,leucoplasts are the builders of starch grains4 ,they take the chemical substance starch and build or mould it into starch grains1 storage starch1 or reserve starch4 ,other characteristic chromoplasts found in plants are yellow and red4 ,yellow chromoplasts occur in carrot root and nasturtium flower petals4 ,red plastids occur in the ripe fruit of capsicum4 ,,starch ,,grains ,the chemical substance starch 7,c,h,o7 is formed in chloroplasts4 ,the starch thus formed is removed from the chloroplasts to other parts of the plant because it is the function of the chloroplasts to manufacture and not to store starch4 ,the starch formed by the chloroplasts is acted upon by a ferment which adds one molecule of water to ,c,h,o1 thus forming sugar ,c,h,o4 ,this sugar is readily soluble in the cell sap1 and is conducted to all parts of the plant4 ,the sugar not utilized in cell metabolism is stored away in the form of reserve starch or starch grains by colorless plastids or amyloplasts4 ,the amyloplasts change the sugar into starch by extracting a molecule of water4 ,this structureless material 7starch7 is then formed by the amyloplast into starch grains having a definite and characteristic form and structure4 ,starch grams vary greatly in different species of plants1 owing probably to the variation of the chemical composition1 density1 etc41 of the protoplast1 and to the environmental conditions under which the plant is growing4 ,,occurrence ,starch grains are simple1 compound1 or aggregate4 ,simple starch grains may occur as isolated grains 7,plates #gj1 #ga1 and #gb71 or they may be associated as in cardamon seed1 white pepper1 cubeb1 and grains of paradise1 where the simple grains stick together in masses1 having the outline of the cells in which they occur4 ,these masses are known as aggregate starch4 ,aggregate starch 7,plate #gf7 varies greatly in size1 form1 and in the nature of the starch grains forming the aggregations4 ,compound starch grains may be composed of two or more parts1 and they are designated as #b1 #c1 #d1 #e1 etc41 compound 7,plate #ge74 ,the parts of a compound grain may be of equal size 7,plate #ge1 ,fig4 #d71 or they may be of unequal size 7,plate #ge1 ,fig4 #b74 ,in most powders large numbers of the parts of the compound grains become separated4 ,the part in contact with other grains shows plane surfaces1 while the external part of the grain has a curved surface4 ,there will be one plane and one curved surface if the grain is a half of a two-compound grain2 two plane and one curved surface if the grain is a part of a three-compound grain1 etc4 ,the simple starch grains forming the aggregations become separated during the milling process and occur singly1 so that in the drugs cited above the starch grains are solitary and aggregate4 ,many plants contain both simple and compound starch grains 7,plate #gd1 ,fig4 #c74 ,in some forms--e4g41 belladonna root 7,plate #ge1 ,fig4 #b7 the compound grains are more numerous2 while in sanguinaria the simple grains are more numerous1 etc4 ,,outline ,the outline of starch grains is made up of 7#a7 rounded1 7#b7 angled1 and 7#c7 rounded and angled surfaces4 ,starch grains with rounded surfaces may be either spherical1 as in ,plate #gd1 ,fig4 #c1 or oblong or elongated1 as in ,plate #ga1 ,fig4 #a4 ,other starches with rounded surfaces are shown on ,plates #gb and #gc4 ,angled outlined grains are common to cardamon seed1 white pepper1 cubebs1 grains of paradise 7,plate #gf1 ,fig4 #d71 and to corn 7,plate #gj1 ,fig4 #c74 ,the outlines of all compound grains are made up partly of plane and partly of curved surfaces4 ,,size ,the size 7greatest diameter7 of starch varies greatly even in the same species1 but for each plant there is a normal variation4 ,in spherical starch grains the size of the individual grains is invariable1 but in elongated starch grains and in parts of compound grains the size will vary according to the part of the grain measured4 ,in zedoary starch 7,plate #ga1 ,fig4 #d71 for instance1 the size will vary according to whether the end1 side1 or surface of the starch grain is in focus4 ,the parts of compound grains often vary greatly in size4 ,such a variation is shown in ,plate #ge1 ,fig4 #b4 ,,hilum ,the hilum is the starting-point of the starch grain or the first part of the grain laid down by the amyloplast4 ,the hilum will be central if formed in the middle of the amyloplast1 and excentral if formed near the surface of the amyloplast4 ,it has been shown that the developing starch grain with eccentric hilum usually extends the wall of the amyloplast if it does not actually break through the wall4 ,starch grains with excentral hilums are therefore longer than broad4 ,illustration3 ,,plate #gj ,,starch #a4 ,calabar bean 7,physostigma venenosum1 ,balfour74 #b4 ,marshmallow root 7,altha officinalis1 ,l474 #c4 ,field corn 7,zea mays1 ,l474 ,illustration3 ,,plate #ga ,,starch #a4 ,galanga root 7,alpinia officinarum1 ,hance74 #b4 ,kola nut 7,cola vera1 ,k4 ,schum474 #c4 ,geranium rhizome 7,geranium maculatum ,l474 #d4 ,zedoary root 7,curcuma zedoaria1 ,rosc474 #d-;,a4 ,surface view of starch grain4 #d-;,b4 ,side view of starch grain4 #d-;,c4 ,end view of starch grain4 ,in central hilum starch grains the grain is laid down around the hilum in the form of concentric layers4 ,these layers are of variable density4 ,the dense layers are formed when plenty of sugar is available1 and the less dense layers are formed when little sugar is available4 ,the unequal density of the different layers gives the striated appearance characteristic of so many starch grains4 ,in eccentric hilum starch grains the starch will be deposited in layers which are outside of and successively farther from the hilum4 ,the term hilum has come to have a broader meaning than formerly4 ,hilum includes at the present time not only the starting-point of the starch grain1 but the fissures which form in the grain upon drying4 ,in all cases these fissures originate in the starting-point1 hilum1 and in some cases extend for some distance from it4 ,the hilum1 when excentral1 may occur in the broad end of the grain1 galanga1 and geranium 7,plate #ga1 ,figs1 #a and #c71 or in the narrow end of the grain1 zedoary 7,plate #ga1 ,fig4 #d74 ,,nature ,,of ,,the ,,hilum ,the hilum1 whether central or excentral1 may be rounded 7,plate #ge1 ,fig4 #a72 or simple cleft1 which may be straight 7,plate #ga1 ,fig4 #a72 or curved cleft 7,plate #ga1 ,fig4 #b72 or the hilum may be a multiple cleft 7,plate #gd1 ,fig4 #c74 ,in studying starches use cold water as the mounting medium1 because in cold water the form and structure are best shown1 and because there is no chemical action on the starch4 ,on the other hand1 the form and structure will vary considerably if the starch is mounted in hot water or in solutions of alkalies or acids4 ,the hilum appears colorless when in sharp focus1 and black when out of focus4 ,starch grains1 when boiled with water1 swell up and finally disintegrate to form starch paste4 ,starch paste turns blue upon the addition of a few drops of weak ,lugol solution4 ,upon heating1 this blue solution is decolorized1 but the color reappears upon cooling4 ,if a strong solution of ,lugol is used in testing1 the color will be bluish black4 ,illustration3 ,,plate #gb ,,starch #a4 ,orris root 7,iris florentinia ,l474 #b4 ,stillingia root 7,stillingia sylvatica1 ,l474 #c4 ,calumba root 7,jateorhiza palmata1 ,lam4 ,miers474 ,illustration3 ,,plate #gc ,,starch #a4 ,male fern 7,dryopteris marginalis1 ,l4 ,a4 ,gray74 #b4 ,african ginger 7,zingiber officinalis1 ,rosc474 #c4 ,yellow dock 7,rumex crispus1 ,l474 #d4 ,pleurisy root 7,asclepias tuberosa1 ,l474 ,illustration3 ,,plate #gd ,,starch #a4 ,kava-kava 7,piper methysticum1 ,forst41 f474 #b4 ,pokeroot 7,phytolacca americana1 ,l474 #c4 ,rhubarb 7,rheum officinale1 ,baill474 ,illustration3 ,,plate #ge ,,starch ,,grains #a4 ,bryonia 7,bryonia alba1 ,l474 #b4 ,belladonna root 7,atropa belladonna1 ,l474 #c4 ,valerian root 7,valeriana officinalis1 ,l474 #d4 ,colchicum root 7,colchicum autumnale1 ,l474 ,illustration3 ,,plate #gf ,,starch ,,masses #a4 ,aggregate starch of cardamon seed 7,elettaria cardamomum1 ,maton74 #b4 ,aggregate starch of white pepper 7,piper nigrum1 ,l474 #c4 ,aggregate starch of cubebs 7,piper cubeba1 ,l41 f474 #d4 ,aggregate starch of grains of paradise 7,amomum melegueta1 ,rosc474 ,,inulin ,inulin is the reserve carbohydrate material found in the plants of the composite family4 ,the medicinal plants containing inulin are dandelion1 chicory1 elecampane1 pyrethrum1 and burdock4 ,plate #gg1 ,figs1 #a and #b show masses of inulin in dandelion and pyrethrum4 ,in these plants the inulin occurs in the form of irregular1 structureless1 grayish-white masses 7,plate #gg74 ,in powdered drugs inulin occurs either in the parenchyma cell or as irregular isolated fragments of variable size and form4 ,inulin is structureless and the inulin from one plant cannot be distinguished microscopically from the inulin of another plant4 ,for this reason inulin has little or no diagnostic value4 ,the presence or absence of inulin should always be noted1 however1 in examining powdered drugs1 because only a few drugs contain inulin4 ,when cold water is added to a powder containing inulin it dissolves4 ,solution will take place more quickly1 however1 in hot water4 ,inulin occurs in the living plant in the form of cell sap4 ,if fresh sections of the plant are placed in alcohol or glycerine1 the inulin precipitates in the form of crystals4 ,,mucilage ,mucilage is of common occurrence in medicinal plants4 ,characteristic mucilage cavities filled with mucilage occur in sassafras stem 7,plate #ff1 ,fig4 #b71 in elm bark 7,plate #ff1 ,fig4 #a71 in althea root1 in the outer layer of mustard seed1 and in the stem of cactus grandiflorus4 ,in addition1 mucilage is found associated with raphides in the crystal cells of sarsaparilla1 squill1 false unicorn1 and polygonatum4 ,when drugs containing mucilage are added to alcohol1 glycerine1 and water mixture1 the mucilage swells slightly and becomes distinctly striated1 but it will not dissolve for a long time4 ,refer to ,plate #gi1 ,fig4 #f4 ,mucilage1 when associated with raphides1 swells and rapidly dissolves when added to alcohol1 glycerine1 and water mixture4 ,the mucilage is1 therefore1 different from the mucilage found in mucilage cavities1 because it is more readily soluble4 ,illustration3 ,,plate #gg ,,inulin 7,inula helenium1 ,l47 #a4 ,inulin in the parenchyma cells of dandelion root4 #b4 ,inulin from ,roman pyrethrum root 7,anacyclus pyrethrum1 ,l4 ,d4 ,c474 ,in coarse-powdered bark and other mucilage containing drugs the mucilage masses are mostly spherical or oval in outline 7,plate #ff1 ,figs4 #b and #c7 the form being similar to the cavity in which the mass occurs4 ,acacia1 tragacanth1 and ,india gum consist of the dried mucilaginous excretions4 ,,hesperidin ,hesperidin occurs in the epidermal cells of short and long buchu4 ,it is particularly characteristic in the epidermal cells of the dried leaves of short buchu4 ,in these leaves the hesperidin occurs in masses which resemble rosette crystals 7,plate #ed1 ,fig4 #a74 ,hesperidin is insoluble in glycerine1 alcohol1 and water1 but it dissolves in alkali hydroxides1 forming a yellowish solution4 ,,volatile ,,oils ,volatile oils occur in cinnamon stem bark1 sassafras root bark1 flowers of cloves1 and in the fruits of allspice1 anise1 fennel1 caraway1 coriander1 and cumin4 ,in none of these cases is the volatile oil diagnostic1 but its presence must always be determined4 ,when a powdered drug containing a volatile oil is placed in alcohol1 glycerine1 and water mixture the volatile oil contained in the tissues will accumulate at the broken end of the cells in the form of rounded globules1 while the volatile oil adhering to the surface of the fragments will dissolve in the mixture and float in the solution near the under side of the cover glass4 ,volatile oil is of little importance in histological work4 ,,tannin ,tannin masses are usually red or reddish brown4 ,tannin occurs in cork cells1 medullary rays of white pine bark 7,plate #dh1 ,fig4 ,b71 stone cells1 and in special tannin sacs4 ,the stone cells of hemlock and tamarac bark and the medullary rays of white pine and hemlock bark contain tannin4 ,tannin associated with prisms occurs in tannin sacs in white pine and tamarac bark4 ,these sacs are frequently several millimeters in length and contain a great number of crystals surrounded by tannin4 ,deposits of tannin are colored bluish black with a solution of ferric chloride4 ,,aleurone ,,grains ,aleurone grains are small granules of variable structure1 size1 and form1 and they are composed of reserve proteins4 ,they occur in celery1 fennel1 coriander1 and anise1 fruits1 in sesame1 sunflower1 curcas1 castor oil1 croton oil1 bitter almond1 and other oil seeds4 ,in many of the seeds the aleurone grains completely fill the cells of the endosperm1 embryo1 and perisperm4 ,in wheat1 rye1 barley1 oats1 and corn the aleurone grains occur only in the outer layer or layers of the endosperm1 the remaining layers in these cases being filled with starch4 ,in powdered drugs the aleurone grains occur in parenchyma cells or free in the field4 ,,structure ,,of ,,aleurone ,,grains ,aleurone grains are very variable in structure4 ,the simplest grains consist of an undifferentiated mass of proteid substance surrounded by a thin outer membrane4 ,in other grains the proteid substance encloses one or more rounded denser proteid bodies known as globoids4 ,in other grains a crystalloid--crystal-like proteid substance--is present in addition to the globoid4 ,in some grains are crystals of calcium oxalate1 which may occur as prisms or as rosettes4 ,all the different parts1 however1 do not occur in any one grain4 ,in castor-oil seed 7,plate #gg;a1 ,fig4 #h7 are shown the membrane 7,a71 the ground mass 7,b71 the crystalloid 7,c71 and the globoid 7,d74 ,,form ,,of ,,aleurone ,,grains ,much attention has been given to the study of the special parts of the aleurone grains1 but one of the most important diagnostic characters has been overlooked1 namely1 that of comparative form4 ,for the purposes of comparing the forms of different grains1 they should be mounted in a medium in which the grain and its various parts are insoluble4 ,oil of cedar is such a medium4 ,the variation in form and size of the aleurone grains when mounted in oil of cedar is shown in ,plate #gg;a4 ,,description ,,of ,,aleurone ,,grains ,the aleurone grains of curcas 7,plate #gg;a1 ,fig4 #a7 vary in form from circular to lens-shaped1 and each grain contains one or more globoids4 ,the globoids are larger when they occur singly4 ,in sunflower seed 7,plate #gg;a1 ,fig4 #b7 the grains vary from reniform to oval1 and one or more globoids are present2 many occur in the center of the grain4 ,the aleurone grains of flaxseed 7,plate #gg;a1 ,fig4 #c7 resemble in form those of sunflower seed1 but the grains are uniformly larger and some of the grains contain as many as five globoids4 ,in bitter almond 7,plate #gg;a1 ,fig4 #d7 the aleurone grains are mostly circular1 but a few are nearly lens-shaped4 ,a few of the large1 rounded grains contain as many as nine globoids2 in such cases one of the globoids is likely to be larger than the others4 ,the aleurone grains of croton-oil seed 7,plate #gg;a1 ,fig4 #e7 are circular in outline1 variable in form1 and each grain contains from one to seven globoids4 ,in sesame seed 7,plate #gg;a1 ,fig4 #f7 the typical grain is angled in outline and the large globoid occurs in the narrow or constricted end4 ,the aleurone grains of castor-oil seed 7,plate #gg;a1 ,fig4 #g7 resemble those of sesame seed1 but they are much larger1 and many of the grains contain three large globoids4 ,when these grains are mounted in sodium-phosphate solution1 the crystalloid becomes visible4 ,,tests ,,for ,,aleurone ,,grains ,aleurone grains are colored yellow with nitric acid and red with ,millon's reagent4 ,the proteid substance of the mass of the grain1 of the globoid1 and of the crystalloid1 reacts differently with different reagents and dyes4 ,the ground substance and the crystalloids are soluble in dilute alkali1 while the globoids are insoluble in dilute alkali4 ,the ground substance and crystalloids are soluble in sodium phosphate1 while the globoids are insoluble in sodium phosphate4 ,calcium oxalate is insoluble in alkali and acetic acid1 but it dissolves in hydrochloric acid4 ,illustration3 ,,plate #gg;a ,,aleurone ,,grains #a4 ,curcas 7,jatropha curcas1 ,l474 #b4 ,sunflower seed 7,helianthus annuus1 ,l474 #c4 ,flaxseed 7,linum usitatissimum1 ,l474 #d4 ,bitter almond 7,prunus amygdalus1 amara1 ,d4,c474 #e4 ,croton-oil seed 7,croton tiglium1 ,l474 #f4 ,sesame seed 7,sesamum indicum1 ,l474 #g and #h4 ,castor-oil seed 7,ricinus communis1 ,l474 ,,crystals ,calcium oxalate crystals form one of the most important inorganic cell contents found in plants1 because of the permanency of the crystals1 and because the forms common to a given species are invariable4 ,by means of calcium oxalate crystals it is possible to distinguish between different species4 ,in butternut root bark1 for instance1 only rosette crystals are found1 while in black walnut root bark--a common substitute for butternut bark--both prisms and rosettes occur4 ,this is only one of the many examples which could be cited4 ,these crystals1 for purposes of study1 will be grouped into four principal classes1 depending upon form and not upon crystal system4 ,these classes are micro-crystals1 raphides1 rosettes1 and solitary crystals4 ,,micro-,,crystals ,micro-crystals are the smallest of all the crystals4 ,under the high power of the microscope they appear as a ,v1 a ,y1 an ,x1 and as a ,t4 ,they are1 therefore1 three- or four-angled 7,plate #gh74 ,the thicker portions of these crystals are the parts usually seen1 but when a close observation of the crystals is made the thin portions of the crystal connecting the thicker parts may also be observed4 ,micro-crystals should be studied with the diaphragm of the microscope nearly closed and with the high-power objective in position4 ,while observing the micro-crystals1 raise and lower the objective by the fine adjustment in order to bring out the structure of the crystal more clearly4 ,micro-crystals occur in parenchyma cells of belladonna1 scopola1 stramonium1 and bittersweet leaves2 in belladonna1 in horse-nettle root1 in scopola rhizome1 in bittersweet stems1 and in yellow and red cinchona bark1 etc4 ,the crystals in each of the above parts of the plant are similar in form1 the only observed variation being that of size4 ,their presence or absence should always be noted when studying powders4 ,,raphides ,raphides1 which are usually seen in longitudinal view1 resemble double-pointed needles4 ,they are circular in cross-section1 and the largest diameter is at the centre1 from which they taper gradually toward either end to a sharp point4 ,illustration3 ,,plate #gh ,,micro-,,crystals #a4 ,horse-nettle root 7,solanum carolinense1 ,l474 #b4 ,scopola rhizome 7,scopolia carniolica1 ,jacq474 #c4 ,belladonna root 7,atropa belladonna1 ,l474 #d4 ,bittersweet stem 7,solanum dulcamara1 ,l474 #e4 ,scopola leaf 7,scopola carniolica1 ,jacq474 #f4 ,tobacco leaf 7,nicotiana tabacum1 ,l474 #g4 ,belladonna leaf 7,atropa belladonna1 ,l474 ,raphides occur in bundles1 as in false unicorn root 7,plate #gi1 ,figs4 #f1 ,a1 ,b1 and ,c71 rarely as solitary crystals4 ,in ipecac root the crystals are usually solitary4 ,in sarsaparilla root1 squill1 etc41 the raphides occur both in clusters1 part of bundle1 or in bundles1 and as solitary crystals4 ,in most drugs the crystals are entire2 but in squills1 where the raphides are very large1 they are broken4 ,in phytolacca 7,plate #gi1 ,fig4 #a7 and in hydrangea the raphides are usually broken1 owing to the fact that these drugs contain large quantities of fibres which break them up into fragments when the drug is milled4 ,there is the greatest possible variation in the size of raphides in the same and in different drugs1 but the larger forms are constant in the same species4 ,raphides are deposited in parenchyma cells and in special raphides sacs4 ,these crystals are always surrounded with mucilage4 ,,rosette ,,crystals ,rosette crystals are compound crystals composed of an aggregation of small crystals arranged in a radiating manner around a central core4 ,this core appears nearly black1 and the whole mass is nearly spherical4 ,the free ends of the crystals are sharp-pointed or blunt4 ,characteristic rosette crystals occur in frangula bark1 spikenard root1 wahoo stem1 root bark1 rhubarb1 etc4 7,plate #hj1 ,figs4 #a1 #b1 #c1 #d1 #e1 and #f74 ,these crystals are very variable in size4 ,this variation is illustrated by the crystals of ,plate #hj4 ,usually there is a variation in size of the crystals occurring in a given plant1 but for each plant there is a more or less uniform variation4 ,for instance1 the largest rosette crystal occurring in wahoo root bark 7,plate #hj1 ,fig4 #e7 is smaller than the largest crystal occurring in rhubarb 7,plate #hj1 ,fig4 #f71 etc4 ,illustration3 ,,plate #gi ,,raphides #a4 ,phytolacca root 7,phytolacca americana1 ,l474 #b4 ,squills 7,urginea maritima ,l4 ,baker74 #c4 ,hydrangea root 7,hydrangea arborescens1 ,l474 #d4 ,convallaria 7,convallaria majalis1 ,l474 #e4 ,carthagean ipecac 7,cephlis acuminata ,karst47 #f4 ,bundle of raphides from false unicorn root4 ,a4 ,bundle surrounded with mucilage4 ,b4 ,mucilage expanded and partially dissolved4 ,c4 ,bundle free of mucilage4 ,illustration3 ,,plate #hj ,,rosette ,,crystals #a4 ,frangula bark 7,rhamnus frangula1 ,l474 #b4 ,white oak bark 7,quercus alba1 ,l474 #c4 ,spikenard root 7,aralia racemosa1 ,l474 #d4 ,wahoo stem bark 7,euonymus atropurpureus1 ,jacq474 #e4 ,wahoo root bark 7,euonymus atropurpureus1 ,jacq474 #f4 ,rhubarb 7,rheum officinale1 ,baill474 ,the prisms forming the rosette crystals1 like all prisms1 decompose white light1 with the result that rosette crystals frequently appear variously colored4 ,rhubarb crystals1 for instance1 are blue or violet4 ,most of the smaller rosette crystals1 however1 appear grayish white with a darker-colored centre4 ,rosette crystals occur in parenchyma cells 7,plate #ha1 ,fig4 #d7 and in medullary rays 7,plate #ha1 ,fig4 #c74 ,,solitary ,,crystals ,solitary crystals are the most variable of all the forms of calcium oxalate4 ,they usually occur in crystal cells associated with bast fibres and stone cells1 less frequently in stone cells 7,plate #cc1 ,fig4 #b74 ,there are many different and characteristic forms of prisms4 ,the more common are3 #a4 ,rectangular3 ,a4 ,parallelepipeds4 ,b4 ,cubes4 #b4 ,polyhedrons3 ,a4 ,irregular polyhedrons4 ,i4 ,flat bases4 7a7 ,non-notched4 7b7 ,notched4 ,,ii4 ,tapering bases4 ,b4 ,octohedrons4 ,the crystals occurring in ,batavia cinnamon and henbane leaves are parallelopipeds 7,plate #hb1 ,figs4 #a and #b74 ,the crystals occurring in cactus grandiflorus1 hemlock bark1 krameria root1 and soap bark are irregular polyhedrons 7,plate #hc74 ,they are longer than broad1 and the ends are tapering4 ,the crystal of cactus grandiflorus has the narrowest diameter of these four1 while the crystals of soap bark have the widest diameter4 ,in coca leaf1 xanthoxylum bark1 elm bark1 ,spanish licorice1 and in white oak 7,plate #hd71 and in cocillina bark 7,plate #hb1 ,fig4 #d7 the crystals are all irregular polyhedrons with flat bases4 ,they are mostly longer than broad and they are all widest in the centre2 in each a few crystals are notched1 but most of the crystals are not notched4 ,the crystals in quassia wood1 uva-ursi leaf1 and most of those of quebracho and wild cherry bark 7,plate #hf1 ,figs4 #a1 #b1 #c1 and #d7 are irregular polyhedrons with flat ends4 ,they are longer than broad1 widest at the centre1 and non-notched4 ,illustration3 ,,plate #ha ,,inclosed ,,rosette ,,crystals #a4 ,hops 7,humulus lupulus1 ,l474 #b4 ,bracts of cannabis indica 7,cannabis sativa1 variety ,indica1 ,lamarck74 #c4 ,medullary rays of canella alba4 #d4 ,parenchyma cells of mandrake 7,podophyllum peltatum1 ,l474 ,illustration3 ,,plate #hb ,,solitary ,,crystal #a4 ,batavia cinnamon 7,cinnamomum burmanni1 ,nees74 #b4 ,henbane leaves 7,hyoscyamus niger1 ,l474 #c4 ,morea nutgalls4 #d4 ,cocillana bark 7,guarea rusbyi ,britton1 ,rusby74 ,illustration3 ,,plate #hc ,,solitary ,,crystals #a4 ,cactus grandiflorus 7,cereus grandiflorus ,l41 ,britton and ,rose74 #b4 ,hemlock bark 7,tsuga canadensis ,l41 ,carr474 #c4 ,krameria root 7,krameria triandra1 ,ruiz and ,pav474 #d4 ,soapbark 7,quillaja saponaria1 ,molina74 ,illustration3 ,,plate #hd ,,solitary ,,crystals #a4 ,coca leaf 7,erythroxylon coca1 ,lamarck74 #b4 ,xanthoxylum bark 7,zanthoxylum americanum1 ,miller74 #c4 ,elm bark 7,ulmus fulva1 ,michaux74 #d4 ,spanish licorice root 7,glycyrrhiza glabra1 ,l474 #e4 ,white oak bark 7,quercus alba1 ,l474 ,cubes occur in senna1 cascara sagrada1 frangula1 white pine1 tamarac 7,plate #he71 quassia1 uva-ursi1 quebracho1 and in wild cherry 7,plate #hf74 ,the crystals of morea nutgalls 7,plate #hb1 ,fig4 #c7 are octahedrons1 and they resemble the crystals of calcium oxalate found in urinary sediments4 ,while studying the prisms1 focus first on the upper surface and then down to the under surface in order to observe the forms accurately4 ,there are several plants in which more than one form of crystal occur4 ,rosette crystals and prisms are associated1 for instance1 in cascara sagrada1 frangula1 condurango1 dogwood1 and pleurisy root 7,plate #hg1 ,figs4 #a1 #b1 #c1 #d1 and #e74 ,an important factor to be kept in mind in studying crystals is the number--whether abundant1 as in rhubarb1 or sparingly present1 as in mandrake1 etc4 ,variation in the number of crystals is not uncommon1 even in different parts of the same plants4 ,in wahoo stem bark1 for instance1 there are several times as many rosette crystals as there are in the root bark4 ,crystals of calcium oxalate are freely soluble in dilute hydrochloric acid without effervescence2 but they are insoluble in acetic acid and in sodium and potassium hydroxide solutions4 ,with sulphuric acid they form crystals of calcium sulphate4 ,,cystoliths ,cystoliths consist of calcium carbonate deposited over and around a framework of cellulose4 ,,forms ,,of ,,cystoliths ,the forms of cystoliths differ greatly in the different plants in which they occur4 ,in the rubber-plant leaf1 the cystolith resembles a bunch of grapes and is stalked2 in ruellia root 7,plate #hg1 ,fig4 #a7 the cystoliths vary from nearly circular to narrowly cylindrical1 and no stalk is present2 also the cystolith nearly fills the cell in which it occurs4 ,in the hair of cannabis indica 7,plate #hh1 ,fig4 #c71 the cystolith varies in form according to the size and shape of the hair1 but in all the hairs the cystolith appears to be attached to the upper curved part of the inner wall of the hair4 ,illustration3 ,,plate #he ,,solitary ,,crystals #a4 ,india senna 7,cassia angustifolia1 ,vahl474 #b4 ,cascara sagrada bark 7,rhamnus purshiana1 ,d4 ,c474 #c4 ,frangula bark 7,rhamnus frangula1 ,l474 #d4 ,white pine bark 7,pinus strobus1 ,l474 #e4 ,tamarac bark 7,larix laricina ,du ,roi1 ,koch74 ,illustration3 ,,plate #hf ,,solitary ,,crystals #a4 ,quassia 7,picrna excelsa ,swartz41 ,lindl474 #b4 ,uva-ursi leaf 7,arctostaphylos uva-ursi ,l41 ,spring474 #c4 ,quebracho bark 7,aspidosperma quebracho-blanco1 ,schlechtendal74 #d4 ,wild-cherry bark 7,prunus serotina1 ,ehrh474 ,illustration3 ,,plate #hg ,,rosette ,,crystals ,,and ,,solitary ,,crystals ,,occurring ,,in #a4 ,cascara sagrada bark 7,rhamnus purshiana1 ,d4,c474 #b4 ,frangula bark 7,rhamnus frangula1 ,l474 #c4 ,cundurango bark 7,marsdenia cundurango1 ,triana ,nichols74 #d4 ,dogwood root bark 7,cornus florida1 ,l474 #e4 ,pleurisy root 7,asclepias tuberosa1 ,l474 ,illustration3 ,,plate #hh ,,cystoliths #a4 ,ruellia root 7,ruellia ciliosa1 ,pursh474 #b4 ,pellionia leaf4 #c4 ,cannabis indica 7,cannabis sativa1 variety ,indica1 ,lam474 ,cystoliths occur1 then1 in special cavities1 in parenchyma cells 7rubber-plant leaf1 fig1 pellionea1 and mulberry71 and in non-glandular hairs 7cannabis indica74 ,in powdered ruellia root the cystoliths occur in or are separated from the parenchyma cells4 ,,tests ,,for ,,cystoliths ,when dilute hydrochloric acid or acetic acid is added to cystoliths a brisk effervescence takes place with the evolution of carbon dioxide gas4 ,part ,,iii ,,histology ,,of ,,roots1 ,,rhizomes1 ,,stems1 ,,barks1 ,,woods1 ,,flowers1 ,,fruits1 ,,and ,,seeds ,in ,part ,,ii the different types of cells and cell contents found in plants have been studied4 ,in ,part ,,iii it will be shown how these different cells are associated and the nature of the cell contents in the different parts of the plant4 ,these parts are the root1 the rhizome1 the stem of herbs1 bark and wood of woody stems1 the leaf1 the flower1 the fruit1 and the seed4 ,,chapter ,i ,,roots ,,and ,,rhizomes ,some fifty-five roots1 rhizomes1 and rhizomes and roots are official in the pharmacopia and national formulary4 ,about #e of these are obtained from monocotyledonous plants1 and #ej from dicotyledonous plants4 ,in studying the structure of roots and rhizomes1 then1 it must first be determined whether the root in question is monocotyledonous or dicotyledonous4 ,this fact is ascertained by determining the type of the fibro-vascular bundle4 ,the bundle is of the open collateral type in all rhizomes and roots obtained from monocotyledonous plants1 but it is closed1 radial1 or concentric in the monocotyledonous type4 ,in both of these groups the cellular plan of structure is similar1 the chief variation being the absence of one or more types of cells1 the variation in the amount1 in arrangement1 in the anatomical structure1 in the color1 and in the cell contents of the individual cells4 ,these facts will be impressed on the mind while studying the rhizomes and the roots4 ,,cross-,,section ,,pink ,,root ,the cross-section of pink root 7,plate #hi7 has the following structure3 ,epidermis4 ,the epidermal cells are small1 nearly as long as broad1 and the outer wall is thicker and darker in color than the side and inner walls4 ,the cells usually contain air4 ,cortex4 ,the cortical parenchyma cells are very large and somewhat rounded in outline1 and the walls are white4 ,there are about twelve rows of these cells1 and each cell contains numerous small1 rounded starch grains4 ,endodermis4 ,the endodermal cells are tangentially elongated1 and the walls are very thin and white4 ,there are two or three layers of endodermal cells2 the cells' outer layers are larger than the cells of the inner layers4 ,illustration3 ,,plate #hi ,,cross-,,section ,,of ,,root ,,of ,,spigelia ,,marylandica1 ,l4 #a4 ,epidermis4 #b4 ,cortical parenchyma4 #b4 ,intercellular space4 #c4 ,endodermis4 #d4 ,pericycle4 #e4 ,cambium4 #f4 ,xylem4 #g4 ,pith4 ,pericycle4 ,the cells forming the pericycle are sieve cells and phloem parenchyma4 ,the sieve cells are small1 angled cells with extremely thin1 white walls4 ,the phloem parenchyma resemble the sieve cells1 except that they are larger4 ,cambium4 ,the cambium cells are rectangular in shape2 the walls are thin and white4 ,xylem4 ,the xylem is composed of tracheids1 wood parenchyma1 and wood fibres4 ,tracheids4 ,the tracheids are the largest diameter cells of the centre of the root4 ,the walls are thick and the cells are slightly angled in outline4 ,wood ,parenchyma4 ,the wood parenchyma cells surrounding the tracheids are five to seven1 angled1 and the walls are not so thick as the walls of the tracheids4 ,medullary ,rays4 ,the medullary ray cells resemble the structure of the wood parenchyma cells1 but they are radially elongated4 ,pith ,parenchyma4 ,the cells forming the pith parenchyma are larger than the cells of wood parenchyma1 but their structure is similar4 ,,cross-,,section ,,ruellia ,,root ,the cross-section of ruellia root 7,plate #ij7 shows the following structure4 ,it should be carefully noted how the structure differs from that of pink root3 ,epidermis4 ,the epidermal cells are angled and variable in size2 many of the epidermal cells are modified as root hairs4 ,hypodermis4 ,the cells of the hypodermis are one layer in thickness and their structure is similar to the epidermal cells4 ,cortex4 ,the cortex contains parenchyma and stone cells4 ,the outer layers of the cortical parenchyma cells are round in outline1 and they contain dark-brown cell contents1 while the cortical parenchyma cells bordering on the endodermis are small and they are free of dark-brown contents4 ,many of the inner parenchyma cells contain amorphous deposits of calcium carbonate4 ,illustration3 ,,plate #ij ,,ruellia ,,root 7,ruellia ciliosa1 ,pursh474 #a4 ,epidermis with root hair4 #b4 ,parenchyma cells with dark contents4 #c4 ,sclerid4 #d4 ,parenchyma without dark cell contents4 #e4 ,endodermis4 #f4 ,bast fibers and phloem4 #g4 ,cambium4 #h4 ,xylem4 #aj4 ,pith4 ,the stone cells are porous and striated1 and the walls are thick and white4 ,endodermis4 ,the endodermal cells are tangentially elongated1 and the walls are thin and white4 ,pericycle4 ,the cells forming the pericycle are the sieve cells1 bast fibres1 and phloem parenchyma4 ,the sieve cells are small1 angled cells with thin1 white walls4 ,the phloem parenchyma cells resemble the sieve cells1 but they are larger4 ,the bast fibres occur singly or in groups of two or three4 ,they are rounded in outline1 and the walls are white1 non-porous1 and non-striated4 ,xylem4 ,the xylem is composed of vessels1 wood parenchyma1 and wood fibres4 ,vessels4 ,the vessels are rounded in outline and few in number4 ,wood ,parenchyma4 ,the wood parenchyma cells are variable in size and shape1 but all the cells are angled in outline4 ,medullary ,rays4 ,the medullary ray cells are not clearly distinguishable4 ,pith ,parenchyma4 ,the pith parenchyma cells of the centre of the root resemble the cortical parenchyma cells4 ,that the structure of rhizomes is similar to the structure of roots is shown by the drawings of spigelia rhizome 7,plate #ia71 and by ruellia rhizome 7,plate #ib74 ,,cross-,,section ,,spigelia ,,rhizome ,the cross-section of spigelia rhizome 7,plate #ia7 is as follows3 ,epidermis4 ,the epidermal cells are nearly angled and free of cell contents4 ,cortex4 ,the cortical parenchyma cells are usually slightly tangentially elongated4 ,the cells of the outer layers are larger than the cells of the inner layers4 ,phloem4 ,the phloem contains sieve cells and phloem parenchyma4 ,the sieve cells are small1 angled cells with thin1 white walls4 ,the phloem parenchyma cells resemble the sieve cells1 but they are larger4 ,illustration3 ,,plate #ia ,,cross-,,section ,,of ,,rhizome ,,of ,,spigelia ,,marylandica1 ,l4 #a4 ,epidermis4 #b4 ,cortical parenchyma4 #c4 ,phloem4 #d4 ,cambium4 #e4 ,xylem4 #f4 ,internal phloem4 #g4 ,pith with starch4 ,illustration3 ,,plate #ib ,,cross-,,section ,,of ,,rhizome ,,of ,,ruellia ,,ciliosa1 ,pursh4 #a4 ,epidermis4 #b4 ,cystolith4 #c4 ,stone cell4 #d4 ,cortical parenchyma4 #e4 ,bast fibres4 #f4 ,pericycle4 #g4 ,xylem4 #h4 ,pith4 ,cambium4 ,the cambium cells are rectangular1 and they are usually not clearly seen because the walls are partially collapsed4 ,xylem4 ,the xylem is composed of vessels1 wood parenchyma1 medullary rays1 and pith parenchyma4 ,vessels4 ,the vessels are slightly angled in outline and few in number4 ,wood ,parenchyma4 ,the wood parenchyma cells are small and angled4 ,medullary ,rays4 ,the medullary ray cells are tangentially elongated1 but in structure resemble the wood parenchyma cells4 ,pith ,parenchyma4 ,the pith parenchyma cells are rounded in outline and contain small1 simple1 rounded starch grains4 ,,cross-,,section ,,ruellia ,,rhizome ,the cross-section of ruellia rhizome 7,plate #ib7 differs from the structure of spigelia rhizome4 ,it is as follows3 ,epidermis4 ,the epidermal cells vary in shape from nearly square to oblong1 and they are filled with dark-brown cell contents4 ,cortex4 ,the cortex contains parenchyma and stone cells4 ,the outer layer of the cortical parenchyma cells are variable in size and many of the cells contain deposits of calcium carbonate and dark cell contents2 the inner parenchyma cells are larger and they are free of the dark-brown cell contents1 but many of the cells contain deposits of calcium carbonate4 ,stone cells with thick1 white1 porous1 and striated walls occur in among the cortical parenchyma cells4 ,phloem4 ,the phloem contains sieve cells1 phloem1 parenchyma1 and bast fibres4 ,the sieve cells are small and with thin1 white1 angled walls4 ,the phloem parenchyma cells resemble the sieve cells1 but they are larger4 ,the bast fibres occur singly or in groups of two or three4 ,the walls are white1 non-porous1 and non-striated4 ,cambium4 ,the cambium layer is composed of rectangularly shaped cells1 which are frequently obliterated4 ,xylem4 ,the xylem contains vessels1 wood parenchyma1 and medullary rays4 ,the vessels are large1 rounded cells with thick walls4 ,the wood parenchyma consists of thick-walled cells of irregular size and form4 ,the medullary rays are tangentially elongated and rectangular in form4 ,pith parenchyma4 ,the pith parenchyma cells are rounded in outline and as large as the cortical parenchyma cells4 ,,powdered ,,pink ,,root ,when the roots and rhizomes of spigelia are powdered 7,plate #ic7 they show the following structure3 ,the epidermal cells are small and brownish on surface view1 varying in size from #ac by #ah micromillimeters to #ca by #dj micromillimeters4 ,when associated with parenchyma they appear as black masses4 ,the cortical parenchyma cells are rounded and vary in size from #bc by #bf micromillimeters to #cg4e by #ij micromillimeters4 ,many of the cells from the root contain larger quantities of minute single rounded starch grains varying in size from #a micromillimeter to #d micromillimeters4 ,the larger round single starch grains are found in both the cortical and pith parenchyma of the rhizome4 ,they vary in size from #e micromillimeters to #ah micromillimeters4 ,the conducting elements are pitted tracheids varying from #aj micromillimeters to #ch micromillimeters in diameter4 ,a few pitted and annular vessels are also found4 ,the only fibres occurring are found in the xylem4 ,they are not a prominent feature of the powder1 as their walls break up into minute fragments4 ,the pith parenchyma varies in size from #ac by #ai micromillimeters to #ge by #hb4e micromillimeters4 ,it is in these cells that the largest starch grains occur4 ,distinguishing diagnostic characters of the powder3 #a4 ,parenchyma with starch4 #b4 ,dark masses of epidermal tissue4 #c4 ,spigelia should contain starch1 and it should not contain cystoliths1 stone cells1 or long1 white-walled bast fibres4 ,,powdered ,,ruellia ,,root ,when the roots of ruellia root and rhizome are powdered 7,plate #id7 they show the following structure3 ,illustration3 ,,plate #ic ,,powdered ,,spigelia ,,marylandica1 ,l4 #a4 ,epidermis and cortical parenchyma4 #b4 ,tracheids and fibres4 #c4 ,parenchyma cells of the root containing the small starch grains1 longitudinal view4 #d4 ,parenchyma of the rhizome containing the large starch grams1 transverse view4 #e4 ,tracheids4 #f4 ,surface view of the epidermal cells4 #g4 ,starch scattered through the field4 #h and #h4 ,dark masses of epidermal and underlying tissue4 ,illustration3 ,,plate #id ,,powdered ,,ruellia ,,ciliosa1 ,pursh4 #a4 ,short1 broad cystoliths from the rhizome1 #a4 ,long cystoliths from the root4 #b and #b4 ,long1 narrow1 white-walled bast fibres4 #c4 ,tracheal tissue from the xylem of the stem4 #d4 ,root parenchyma4 #e4 ,tracheal tissue from the xylem of the root4 #f4 ,cortical parenchyma cells from the rhizome with short1 broad cystoliths4 #g and #g4 ,long1 thick-walled sclerids from the root4 #h4 ,short1 broad sclerids from the stem4 #i4 ,pitted pith parenchyma from the stem with intercellular space4 #aj4 ,parenchyma of the root with sclerid and cystolith1 longitudinal view4 ,the epidermal cells vary from #g4h by #ae4f micromillimeters to #ae4a by #af4f micromillimeters4 ,the cell contents are dark and the walls are light4 ,a few rows of the outer cortical parenchyma cells of both the rhizome and the root have dark cell contents and white walls4 ,the dark contents disappear toward the phloem4 ,the cortical cells vary from #ac4f by #ad4c micromillimeters to #hi4e by #ij4i micromillimeters4 ,in the cortical parenchyma cells of the rhizome are found the short1 broad cystoliths measuring up to #eb by #fb micromillimeters4 ,in the corresponding cells of the root are found the long1 narrow cystoliths which measure up to #fh4d by #ahg4b micromillimeters4 ,scattered throughout the powder are seen three distinct types of sclerids 7stone cells7 which are associated with the cortical parenchyma of both the stem and the root4 ,most of them are found1 however1 in the roots4 ,first1 the short1 broad stone cells from the stem basis have square ends2 the walls vary from #ac to #ai4e micromillimeters in thickness with branching pores which extend toward the adjacent cell4 ,these sclerids vary in size from #eb by #ed4f micromillimeters to #de by #acj micromillimeters4 ,secondly1 the long stone cells from the root vary from #cb by #if micromillimeters to #de4e by #edb4e micromillimeters with walls #af micromillimeters thick4 ,the width of the cell and the thickness of the wall vary but little throughout their entire length4 ,the third type of stone cell also from the root has unequally thickened walls and the ends are square or blunt4 ,a few long1 narrow1 colorless1 thin-walled bast fibres also occur4 ,they are #ac micromillimeters wide1 with walls #c4i micromillimeters thick4 ,annular spiral and pitted vessels are also found scattered throughout the powder4 ,the diagnostic characters of the powder are3 #a4 ,the short1 broad1 and long1 narrow cystoliths4 #b4 ,the short1 broad1 and long1 narrow sclerids4 #c4 ,the long1 narrow1 thin1 white-walled bast fibres4 ,in poke root1 ipecac1 sarsaparilla1 and veratrum are raphides4 ,in belladonna and horse-nettle roots are micro-crystals4 ,in calumba1 stillingea1 krameria1 licorice1 scamony root are prisms4 ,in saponaria1 jalap1 althea1 spikenard1 rumex1 rhubarb are rosette crystals4 ,in pleurisy roots both prisms and rosettes occur4 ,in gentian1 senega1 symphytuns1 lovage1 parsley1 inula1 echinacea1 angelica1 burdock1 and chicory no crystals of any kind occur4 ,root hairs occur in cross-sections of sarsaparilla root and false unicorn1 but with these exceptions3 root hairs do not occur on roots1 because the younger part of the root with root hairs is not removed from the soil when the drug is collected4 ,in sarsaparilla root there are several layers of hypodermal cells2 in most roots there are no hypodermal cells4 ,in the non-woody roots or the roots of herbs the parenchyma cells form the greater part of the tissues of the root4 ,in ruellia root are stone cells2 in spigelia root and many other roots there are no stone cells4 ,in ruellia root are bast fibres2 in spigelia1 gentian1 ipecac1 chicory1 dandelion1 symphytum1 and lovage no bast fibres occur4 ,in all the woody roots there is a periderm consisting of typical cork cells1 as in black haw2 or stone cells1 as in asclepias2 or of a mixture of lifeless parenchyma1 medullary rays1 etc41 as in ,oregon grape root4 ,woody roots have a phellogen layer which is absent in the non-woody roots4 ,the numbers of layers of cortical parenchyma differ in the same root according to its age1 but for a given root there is a normal variation4 ,the number of layers of cortical parenchyma in proportion to other cells is less in woody roots4 ,in woody roots there is no endodermis4 ,the cambium in these cases shows clearly between the phloem and the xylem part of the fibro-vascular bundle4 ,in woody roots the wood fibres are well developed and form a large part of the root1 and the medullary rays have pitted side and end walls4 ,the description given above of ruellia root is not typical of all roots1 but the structure represents the greater number of the elements that it is possible to find in a root4 ,in many roots1 for instance1 there are no stone cells1 in others no epidermis and no endodermis4 ,in asclepias1 aconite1 and calumba stone cells occur4 ,in symphytum1 chicory1 dandelion1 burdock1 elecampane1 pyre thrum1 gentian1 and senega no stone cells occur4 ,in aconite1 althea1 asclepias1 belladonna1 bryonia1 columba1 ipecac1 jalap1 krameria1 sarsaparilla1 scamony1 stillingea1 and rumex are characteristic starch grains4 ,symphytum1 chicory1 dandelion1 burdock1 elecampane1 and pyrethrum contain inulin1 but no starch4 ,in saponaria1 gentian1 and senega neither starch nor inulin occurs4 ,when studying roots the nature of the epidermis or the periderm must be considered1 as also the number of layers of cortical parenchyma2 the occurrence1 distribution1 and amount of stone cells when present2 the presence or absence of the endodermis2 the occurrence and structure of bast fibres when present2 the nature of the cambium cells2 the width and structure of the medullary rays1 the size of the wood fibres and wood parenchyma1 and the nature of the cell contents and the arrangement of the fibro-vascular bundle4 ,,chapter ,,ii ,,stems ,when studying stems it should first be determined whether they were derived from monocotyledonous or dicotyledonous plants4 ,this fact is ascertained by determining the type of the fibro-vascular bundle4 ,see ,chapter ,,xi4 ,the next fact to determine is whether the stem is from an herb or from a woody plant4 ,this fact is readily determined because herbaceous stems have a true epidermis1 masses of collenchyma at the angles of the stem4 ,the cortical cells contain chlorophyll1 and the pith is very large4 ,woody stems have a corky layer1 a phellogen layer1 and the pith is very small except in the very young woody stems4 ,having determined these facts1 a study should be made of the arrangement1 form1 structure1 color1 and the cell contents of the different cells in order to determine the species of plant from which the stem was obtained4 ,,herbaceous ,,stems ,the great variation in the structure of herbaceous stems is shown in the cross-sections of spigelia 7,plate #ie72 in ruellia 7,plate #if72 in the charts of powdered genuine horehound1 powdered spurious horehound1 and in the chart of powdered insect flower stems4 ,,cross-,,section ,,spigelia ,,stem ,spigelia stem 7,plate #ie7 has the following characteristic structure3 ,epidermis4 ,the epidermal cells are papillate4 ,cortex4 ,the cortical parenchyma cells consist of tangentially elongated cells which are oval in outline4 ,phloem4 ,the phloem consists of sieve cells1 phloem parenchyma1 and of bast fibres4 ,illustration3 ,,plate #ie ,,cross-,,section ,,of ,,stem ,,of ,,spigelia ,,marylandica1 ,l4 #a4 ,papillate epidermis4 #d4 ,phloem4 #g4 ,inner phloem4 #b4 ,cortical parenchyma4 #e4 ,cambium4 #h4 ,pith4 #c4 ,bast stereome4 #f4 ,xylem4 ,the sieve cells are small1 and with thin1 white1 angled walls4 ,the phloem parenchyma resembles the sieve cells1 but they are larger4 ,the bast fibres are rounded in outline and the walls are thick1 white1 non-porous1 and non-striated4 ,cambium4 ,the cambium cells are rectangular in shape or the walls are collapsed and the cells indistinct4 ,xylem4 ,the xylem contains vessels1 wood parenchyma1 medullary rays4 ,the vessels are small and angled1 the walls are thick and white4 ,wood parenchyma4 ,the cells are variable in size and shape1 and the walls are thick4 ,the medullary ray cells are small1 narrow1 and tangentially elongated4 ,internal ,phloem4 ,external to the pith parenchyma are isolated groups of internal phloem consisting of sieve cells4 ,pith ,parenchyma4 ,the pith parenchyma cells are oval in form and irregularly placed4 ,the cells contain small1 simple starch grains4 ,,ruellia ,,stem ,the cross-section of ruellia stem 7,plate #if7 is as follows3 ,epidermis4 ,the epidermal cells are variable in shape and very large4 ,there are no cell contents4 ,cortex4 ,the cortex consists of collenchyma and parenchyma cells and stone cells4 ,the collenchyma cells have very small1 angled cavities and very thick walls4 ,these cells make up the greater part of the cortex4 ,the cortical parenchyma cells are variable in size and shape4 ,the stone cells occur singly or in groups4 ,the walls are thick1 white1 porous1 and striated1 and the central cavity is frequently quite large4 ,phloem4 ,the phloem contains sieve cells1 phloem parenchyma1 and bast fibres4 ,the sieve cells have thin1 white1 angled walls4 ,the phloem parenchyma cells are frequently tangentially elongated1 otherwise they resemble the sieve cells4 ,the bast fibres occur alone or in groups4 ,the walls are thick1 white and porous4 ,illustration3 ,,plate #if ,,cross-,,section ,,of ,,stem ,,of ,,ruellia ,,ciliosa1 ,pursh4 #a4 ,epidermis4 #b4 ,collenchyma4 #c4 ,parenchyma4 #d4 ,sclerids4 #e4 ,bast fibres4 #f4 ,phloem4 #g4 ,cambium cells4 #h4 ,xylem4 #aj4 ,pith parenchyma4 ,cambium4 ,the cambium cells are rectangular in shape and the walls are thin4 ,xylem4 ,the xylem contains vessels1 wood parenchyma1 and medullary rays4 ,the vessels are large2 the walls are thick1 white1 and angled4 ,the wood parenchyma cells are variable in size and shape and the walls are angled4 ,the medullary ray cells are radially elongated and rectangular in shape4 ,pith ,parenchyma4 ,the pith parenchyma cells are large and rounded in shape4 ,,powdered ,,horehound ,the structure of powdered horehound is shown in ,chart #ig4 ,the epidermal cells of the leaf 7#a7 are wavy in outline1 the guard cells are elliptical1 the stoma lens-shaped1 the epidermis often showing hairy outgrowth as in the illustration4 ,the epidermal cells of the petals 7#b7 have irregularly thickened beaded walls4 ,the non-glandular hairs from the calyx 7#c72 the long1 thin-walled1 multicellular non-glandular twisted hairs 7#d7 from the leaves and stems2 long1 thin-walled1 unicellular hairs 7#e7 from the tube of the corolla2 the glandular hairs 7#f7 with a one-celled stalk and with two secreting cells divided by vertical walls2 the eight-celled glandular hair 7#g7 as seen in surface and side view2 the spiral and reticulated conducting cells 7#h72 the thick1 white-walled fibres from the stem 7#i72 the pollen grains 7#aj7 with nearly smooth walls4 ,the diagnostic elements of the ,u4 ,s4 ,p4 horehound are the long1 twisted1 multicellular hairs 7#d71 the glandular hairs 7#g71 and the pollen grains 7#aj74 ,,powdered ,,spurious ,,horehound ,marrubium peregrinum1 which is a related species of horehound and which is a common adulterant of horehound1 has the following structure 7,plate #ih73 ,illustration3 ,,plate #ig ,,powdered ,,horehound 7,marrubium vulgare1 ,l74 #a4 ,epidermis of leaf showing the wavy epidermal cells1 stoma1 and a clustered hair4 #b4 ,surface view of the petal epidermis4 #c4 ,non-glandular hair from the calyx or corolla4 #d4 ,long1 thin-walled1 twisted1 non-glandular hairs from the leaves and stem4 #e4 ,unicellular non-glandular hair from the tube of the corolla4 #f4 ,glandular hairs with a one-celled stalk and with two secreting cells divided by vertical walls4 #g4 ,surface and side view of the eight-celled glandular hairs4 #h4 ,conducting cells4 #i4 ,fibres from the stem4 #aj4 ,pollen grains4 ,illustration3 ,,plate #ih ,,spurious ,,horehound 7,marrubium peregrinum1 ,l47 #a4 ,surface view of the leaf epidermis4 #b4 ,view of the petal epidermis4 #c4 ,non-glandular multicellular branched hair from the stem1 leaves1 or flowers with a few of the lower branches broken4 #d4 ,broken pieces and branches from the compound hairs scattered throughout the field4 #e4 ,unicellular glandular hair with a two-celled stalk4 #f4 ,under-surface view of an eight-celled glandular hair4 #g4 ,side view of eight-celled glandular hair4 #h4 ,long1 pointed1 unicellular1 non-glandular hair from the corolla1 the wall irregularly thickened near the apex4 #i4 ,fibres4 #aj4 ,pollen grains1 #aa4 ,conducting cells of leaf4 ,illustration3 ,,plate #ii ,,powdered ,,insect ,,flower ,,stems 7,chrysanthemum cinerariifolium1 ,trev41 ,vis47 #a4 ,surface view of epidermis4 #b4 ,cross-section of epidermis4 #c4 ,hairs4 #d4 ,fibres4 #e4 ,cross-section of fibres4 #f4 ,longitudinal view of pith parenchyma4 #g4 ,cross-section of pith parenchyma4 #h4 ,conducting cells4 ,the wavy leaf epidermis 7#a7 with stoma2 the beaded wall petal epidermis 7#b72 the non-glandular1 multicellular branched hairs 7#c7 from the stem leaves or flowers2 the broken pieces and branches of the compound hairs 7#d7 scattered throughout the field2 the glandular hairs 7#e7 with a two-celled stalk2 the eight-celled glandular hair 7#g7 seen in surface view and a side view 7#h7 of a similar hair2 the long1 pointed1 unicellular non-glandular hair from the tube of the corolla1 the wall irregularly thickened near the apex2 the fibres 7#i7 from the stem2 the pollen grains 7#aj7 with prominent centrifugal projections2 the conducting cells4 ,the diagnostic elements of marrubium peregrinum are the multicellular branched hairs 7#c7 which occur on all parts of the plant1 usually much broken in the powder1 with walls many times thicker than the walls of the hairs found in ,u4 ,s4 ,p4 horehound2 the pollen grains 7#aj7 with centrifugal projections and the stalked glandular hairs 7#e74 ,,insect ,,flower ,,stems ,insect flower stems are the chief adulterant of insect flowers4 ,until the passage of the insecticide law1 it was a common practice to sell 7for insect powder7 a mixture of powdered stems and flowers4 ,since the passage of the law1 the presence of the stems in a powder is supposed to be declared on the label4 ,in spite of the penalties attached1 their presence in a powder is frequently not declared1 as evidenced by a microscopical examination of the insect powders obtained in the open market4 ,the structure of powdered insect flower stems 7,chart #ii7 is as follows3 ,the epidermal cells of the stems are prominently marked with stoma and angled1 striated wall cells 7,fig4 #a74 ,on cross-section 7,fig4 #b7 the stem is seen to be made up of epidermal cells with thick outer and thin side walls 7,fig4 #b74 ,the ,t-shaped hairs 7,fig4 #c7 are longer than those found on any other part of the plant4 ,the fibres 7,fig4 #d7 are the most characteristic part of the powder4 ,they are elongated1 and the walls are white and slightly porous and of nearly uniform thickness4 ,they occur free in the field or in groups of two or more4 ,the cross-section view of these fibres is shown in ,fig4 #e4 ,the pith parenchyma 7,fig4 #f7 is abundant and is composed of thick1 porous-walled cells4 ,on cross-section the cells are rounded and are separated by intercellular spaces4 ,the conducting cells 7,fig4 #h7 vary from spiral to reticulate4 ,,chapter ,,iii ,,woody ,,stems ,,buchu ,,stem ,the cross-section of a buchu stem 7,plate ,c71 #a4f millimeters in diameter1 shows a few of the epidermal cells modified into thick-walled1 roughish1 unicellular trichomes 7#a74 ,the remaining epidermal cells have a thick1 wavy outer wall 7#b74 ,beneath the epidermis are several rows of cortical parenchyma cells 7#c7 which extend to the bast bundles and in which are found the secretory cavities with the thin-walled secretory cells 7#d74 ,the bast fibres 7#e7 occur in continuous bands1 varying greatly in size2 the walls are whitish and of variable thickness4 ,inside the bast fibres1 the small irregular sieve cells 7#f7 occur in groups1 surrounded by the phloem parenchyma 7#h74 ,the radially elongated cells of the medullary rays 7#g7 extend outward from the xylem1 increasing in number in the outer portions of the wood1 and extending nearly to the bast fibres4 ,no distinct cambium layer is visible4 ,the conducting cells 7#i7 occur throughout the xylem surrounded by the wood fibres and wood parenchyma 7#aj74 ,the latter is not very abundant in buchu4 ,the medullary rays border on the conducting cells and extend outward to the phloem4 ,the pith parenchyma cells are nearly circular in outline and often show a perforated end wall when a cell happens to be cut just above or below that point4 ,,mature ,,buchu ,,stem ,in ,plate #aja-;,a is shown the cork formation or secondary growth as seen in the older1 larger buchu stems4 ,the wavy epidermis 7#a71 which is the primary epidermis and which has disappeared on many portions of the stem1 has thin side walls and dark cell contents 7#b74 ,next to the epidermal cells occur several rows of peculiarly arched cork cells with thick1 white outer walls 7#c7 and reddish-brown cell contents 7#d74 ,the cork cambium 7#e7 is typical in form1 and it has formed one or two layers of phelloderm cells 7#f7 which have the same form as the cambium cells but with thicker walls4 ,next to the phelloderm occur the cortical parenchyma cells4 ,the remaining structure of the mature stem is identical with that of ,fig4 #b4 ,illustration3 ,,plate #ajj ,,cross-,,section ,,of ,,buchu ,,stems 7,barosma betulina ,berg41 ,barth1 and ,wendl47 #a4 ,hairs4 #b4 ,wavy epidermis4 #c4 ,cortical parenchyma4 #d4 ,secretion cells and cavity4 #e4 ,group of bast fibres4 #f4 ,sieve cells4 #g4 ,medullary rays4 #h4 ,phloem parenchyma4 #i4 ,vessels4 #aj4 ,wood fibres1 and wood parenchyma4 #aa4 ,pith parenchyma4 ,illustration3 ,,plate #aja ,a4 ,cross-section of buchu stem 7,barosma betulina ,berg41 ,barth4 and ,wendl474 #a1 ,outer wall of epidermis2 #b1 ,cell cavity of epidermal cell2 #c1 ,wall of cork cell2 #d1 ,cavity of cork cell2 #e1 ,phellogen layer2 #f1 ,divided phellogen cell changing into a cortical parenchyma cell2 #g1 ,cortical parenchyma cell4 ,b4 ,cross-section of leptandra rhizome 7,leptandra virginica ,l41 ,nutt474 #a1 ,parenchyma cells undergoing change in the composition of their walls2 #b1 ,a break in the epidermal tissue2 #c1 ,parenchyma cells undergoing division4 ,,powdered ,,buchu ,,stem ,powdered buchu stem 7,plate #ajb7 has many striking features which make it easy of identification when mixed with buchu leaves4 ,a few unicellular1 rough1 thick1 white-walled trichomes 7#a7 occur distributed throughout the field4 ,they are straight or slightly curved and vary in length from #dj to #ajj microns2 in thickness at the bast they measure from #aj to #bb microns4 ,the central cavity varies greatly1 and in some trichomes seems to have disappeared entirely4 ,the epidermal cells 7#b7 are very characteristic1 occurring singly or in groups of two or more4 ,the cells from the older stems often appear reddish brown by transmitted light1 while the epidermal cells from the younger stems appear whitish opaque 7porcelain-like74 ,they are usually six-sided and angular in outline4 ,the cortical parenchyma cells 7#c7 on transverse view have a rounded cell cavity and intercellular spaces between the walls4 ,the double walls vary in thickness1 the greatest thickness being about #i microns4 ,the parenchyma cells 7#c7 on longitudinal view show square ends and often contain sphro-crystalline masses of hesperidin4 ,the thin-walled sieve cells and the surrounding cells are scarcely ever seen in the powder4 ,the white-walled pointed stereomes 7#d7 are a characteristic feature of the powder2 they vary greatly in length1 in diameter and in the thickness of their walls4 ,in a number eighty powder the fibres are mostly broken4 ,the greatest length of the unbroken fibres is #a4be microns4 ,the thickest wall measured #e microns and the greatest observed width was #be microns4 ,the spiral reticulate and scalariform thickened conducting cells occur scattered throughout the powder4 ,the reticulate and scalariform cells usually occur with wood fibres4 ,it is an interesting fact that the spiral thickening in conducting cells is usually separate from the side wall and nearly always appears as indicated at #e4 ,an occasional rosette crystal of calcium oxalate 7#f7 is seen in the field4 ,the wood parenchyma 7#g71 which makes up a very small percentage of the xylem1 is not readily found in the powder4 ,the pith parenchyma cells 7#h7 have thick1 porous side walls and perforated side walls4 ,the wood fibres 7#i7 usually occur in masses surrounding the conducting cells2 when occurring singly1 the oblique pores readily distinguish them from the bast fibres4 ,illustration3 ,,plate #ajb ,,powdered ,,buchu ,,stems 7,barosma betulina ,berg41 ,barth4 and ,wendl474 #a4 ,hairs4 #b4 ,epidermal cells1 the larger pieces reddish-brown2 the smaller aggregations white4 #c4 ,transverse cortical parenchyma4 #c' ,longitudinal cortical parenchyma with sphro crystalline masses of hesperidin4 #d4 ,bast fibres4 #e4 ,spiral1 sclariform1 and reticulate vessels4 #f4 ,rosette crystals of calcium oxalate4 #g4 ,wood parenchyma4 #h4 ,pith parenchyma with porous side and end walls4 #i4 ,wood fibres4 ,the diagnostic elements of powdered buchu stems are3 ,first1 trichomes2 secondly1 reddish-brown and white-angled epidermal cells2 thirdly1 the long1 white bast fibres4 ,,chapter ,,iv ,,barks ,barks are all obtained from dicotyledonous plants4 ,in studying barks there should be ascertained the thickness1 arrangement1 form1 structure1 color1 and cell contents of the cells occurring in the outer1 middle1 and inner barks4 ,the outer bark includes the cork cells and the phellogen layer4 ,the middle bark includes all the cells occurring between the phellogen layer and the beginning of the medullary rays4 ,the inner bark includes the medullary ray cells and all cells associated with them4 ,the plan of structure of all barks is similar1 but in each species of plant the structure of the bark is uniform and characteristic for the species4 ,a great number of drugs consist of the bark of woody plants2 for this reason the bark is considered in a separate chapter from the stem4 ,,white ,,pine ,,bark ,the cross-section of white pine bark 7,plate #ajc7 has the following structure3 ,outer ,bark4 ,the periderm consists of several layers of reddish-brown cork cells 7#a7 which are narrow1 elongated1 and with thin walls4 ,middle ,bark4 ,the cells forming the middle bark are parenchyma and secretion cells4 ,the parenchyma cells vary greatly in size1 form1 and thickness of the walls4 ,the cells beneath the cork cells and around the secretion cells are tangentially elongated and oval in shape1 while the other parenchyma cells are more irregular in shape4 ,the secretion cells are arranged around the schizogenous secretion cavities4 ,the cells are tangentially elongated1 and the walls1 which are slightly papillate1 are white4 ,inner ,bark4 ,the cells forming the inner bark are medullary rays1 parenchyma1 sieve cells1 and storage cavities4 ,illustration3 ,,plate #ajc ,,cross-,,section ,,of ,,unrossed ,,white ,,pine ,,bark 7,pinus strobus1 ,l47 #a4 ,cork cells of the epidermis4 #b4 ,parenchyma cells filled with chlorophyl4 #c4 ,intercellular space4 #d4 ,secretion cavity with resin4 #e4 ,secretion cells4 #f1 ,one or more circles of parenchyma filled with chlorophyl4 #g4 ,parenchyma4 #h4 ,medullary rays4 #i4 ,sieve cells4 #aj4 ,storage cavities4 ,the medullary rays form wavy lines4 ,the medullary ray cells are radially elongated1 rectangular in shape1 and they contain granular cell contents4 ,the sieve cells are either square or rectangular in shape4 ,the walls are thin and white4 ,the storage cavities are either filled with starch or with prisms and tannin4 ,,powdered ,,white ,,pine ,,bark ,white pine bark 7,plate #ajd7 when powdered shows the following characteristic elements3 ,the microscopic structure of a powdered white pine is as follows3 ,the epidermis 7#a7 consists of reddish-brown masses1 irregular in outline4 ,the outer parenchyma cells are of a bright-green color1 owing to the presence of chlorophyll4 7,the above elements are not usually found in the rossed bark47 ,the parenchyma 7#c7 with starch usually occurs in longitudinal sections accompanied with sieve cells4 ,often the tissue separates transversely1 showing the medullary rays 7#d7 with their granular cell contents 7#i7 and the inner parenchyma cells filled with starch and the surrounding sieve cells4 ,the crystals are nearly perfect cubes and occur singly 7#e7 or in groups 7#f74 ,on the longitudinal section of the bark the crystals occur in parenchyma cells surrounded by a reddish cell content and form parallel rows which are very characteristic4 ,the resin occurs either as white1 angled fragments 7#g7 in a water mount1 or as globular mass 7#h7 or as reddish-brown pieces 7#aj74 ,the starch is very abundant and is distributed through the field4 ,the diagnostic grain is lens-shaped1 with a cleft hilum1 which is nearly straight1 or slightly curved1 and runs parallel to the long diameter of the grain4 ,the addition of ferric chlorid ,t4 ,s4 will show the presence of tannin by forming a dark coloration4 ,the identification of the starch is facilitated by the addition of a weak ,lugol's solution1 which imparts a blue coloration to the starch grain4 ,the form1 amount1 and distribution of the cells composing the bark differ greatly in different plants4 ,in cramp bark the cork and phellogen cells are very large1 while in cascara sagrada the phellogen and the cork cells are very small4 ,illustration3 ,,plate #ajd ,,powdered ,,white ,,pine ,,bark 7,pinus strobus1 ,l47 #a4 ,epidermis4 #b4 ,parenchyma cells4 #c4 ,parenchyma with starch4 #d4 ,medullary rays4 #e4 ,solitary crystals4 #f4 ,solitary crystals and tannin4 #g1 #h and #aj4 ,resin masses4 #i4 ,starch4 ,in canella alba bark the periderm is composed of stone cell cork or stone cells arranged in superimposed rows1 which form the outer layers of the bark4 ,in white oak and most barks from woody trees the periderm consists of lifeless parenchyma1 medullary rays1 sieve cells1 bast fibres1 and in some cases stone cells and of phellogen cells4 ,in young wild cherry1 cascara sagrada1 and frangula are several layers of tangentially elongated collenchyma cells with chlorophyll4 ,in the older barks of the above and in many other barks no collenchyma cells occur4 ,in cramp bark and in tulip tree bark the outer layers of the cortical parenchyma cells are beaded4 ,in most barks there is no beaded walled parenchyma4 ,the outer layers of most cortical parenchyma cells are tangentially elongated while the inner parenchyma cells are mostly circular in outline4 ,in white oak1 cascara sagrada and prickly ash are groups of stone cells2 in the cinnamon barks are bands of stone cells2 in cinchona bark are isolated stone cells4 ,in cramp bark1 mezerum1 elm1 and white pine bark no stone cells occur4 ,in frangula1 cascara sagrada1 cocillina1 cinnamon1 cinchona1 sassafras1 and wild cherry barks the bast fibres occur in groups4 ,in frangula1 cascara sagrada1 and cocillina the bast fibres are surrounded by crystal cells with crystals4 ,in sassafras bark mucilage cells occur4 ,in canella alba1 white pine1 and sassafras barks secretion cells occur2 but in most barks no secretion cells occur4 ,in sassafras bark the medullary ray cells are nearly as broad as long2 in cramp bark they are elongated and oval in shape4 ,in cascara sagrada1 as in most barks1 the cells are longer than broad and rectangular in shape4 ,in cascara sagrada the sieve cells are very large2 in granatum bark the sieve cells are very small4 ,in cassia cinnamon and in canella alba bark the walls of the sieve cells have collapsed1 with the result that the sieve cells have become partly obliterated4 ,in witch-hazel1 mountain maple1 willow1 and black walnut are found prisms2 in cramp bark1 black haw1 wahoo1 pomegranate1 and cotton root bark are found rosette crystals2 in the cinnamon barks are found raphides2 in cinchona bark1 micro-crystals4 ,in cocillina1 frangula1 cascara sagrada1 white oak1 poplar and ,jamaica dogwood barks are found crystal-bearing fibres 7,plates #ai and #bj74 ,when studying barks we must consider the kind1 structure1 and amount of the periderm2 the nature of the phellogen2 the nature and amount of the cortical parenchyma2 the occurrence1 distribution1 and amount of stone cells1 when present2 the occurrence and structure of the bast fibres2 the presence or absence of secretion cells2 the width1 distribution1 and structure of the medullary rays4 ,,chapter ,v ,,woods ,quite a number of drugs consist of the wood of woody plants2 such drugs are quassia1 red saunders1 white sandalwood1 and guaiac4 ,when studying woods it is necessary to observe the cross1 tangential1 and radial sections4 ,such sections of quassia are shown in ,plates #aje1 #ajf1 and #ajg4 ,when studying these sections it should be remembered that while the types of cells forming quassia wood are similar to the cells forming other woods1 still their structure1 arrangement1 and amount will vary in a recognizable way in the different woods4 ,,cross-,,section ,,quassia ,plate #aje is a cross-section of quassia4 ,it has the following structure3 ,vessels4 ,the vessels occur singly or in groups of two to eight cells4 ,the cells are variable in size and shape4 ,the walls are yellowish white and porous4 ,medullary ,rays4 ,the medullary rays vary from one to five cells in width4 ,the medullary ray cells are radially elongated and the walls are strongly porous4 ,wood ,parenchyma4 ,the wood parenchyma cells have thin1 yellowish-white1 angled walls4 ,wood ,fibres4 ,the wood fibres have thick1 yellowish-white1 angled walls4 ,these cells are smaller in diameter than the wood parenchyma cells4 ,,radial ,,section ,,quassia ,the radial section of quassia 7,plate #ajg7 is as follows3 ,vessels4 ,the vessels appear as in the tangential section4 ,medullary rays4 ,the medullary rays vary from ten to twenty cells in height according to the part of the medullary ray bundle cut across4 ,illustration3 ,,plate #aje ,,cross-,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #a4 ,vessels4 #b4 ,medullary rays4 #c4 ,wood parenchyma4 #d4 ,wood fibres4 ,illustration3 ,,plate #ajf ,,tangential ,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #a4 ,vessel4 #b4 ,wood parenchyma4 #c4 ,wood fibre4 #d4 ,end wall of medullary ray cell4 #e4 ,medullary ray bundle4 ,illustration3 ,,plate #ajg ,,radial ,,section ,,of ,,quassia ,,wood 7,picrna excelsa ,sw41 ,lindl47 #a4 ,showing the height and length of the medullary rays and cells4 #b4 ,cells with starch4 #c4 ,wood parenchyma and wood fibres4 ,the medullary ray cells exhibit their height and length4 ,the walls of the cells are yellowish white and strongly porous4 ,wood ,parenchyma4 ,the wood parenchyma cells have yellowish1 thin walls and blunt end walls4 ,wood ,fibres4 ,the wood fibres have thick1 yellowish-white walls1 and the end of the cells are strongly tapering4 ,,tangential ,,section ,,quassia ,the tangential section of quassia 7,plate #ajf7 shows the following structure3 ,vessels4 ,the vessels are very long and broad and the yellow walls are marked with clearly defined pits4 ,medullary ,rays4 ,the tangential section shows the cross-section of the medullary ray bundle and the cross-section of the medullary ray cell4 ,the medullary ray bundle varies in width from one to five cells4 ,the ends of the bundles are always one cell in width1 while the central part of the bundle is frequently five cells in width4 ,the medullary ray cell varies in size1 structure1 and shape according to the part of the cell cut across4 ,the cells cut across the centre show hollow spaces1 but the cells cut just above or below the end wall show a strongly pitted surface4 ,the cells forming the end of the bundle are larger than the cells forming the centre of the bundle4 ,wood ,parenchyma4 ,the wood parenchyma cells are greatly elongated and the walls are thin and yellowish white4 ,the ends of the cells are blunt4 ,wood ,fibres4 ,the wood fibres are elongated1 the walls are thick and the cells are strongly tapering4 ,in quassia1 white sandalwood1 red sandalwood1 and guaiac wood are characteristic crystals4 ,in quassia the vessels are finely pitted1 yellowish1 and distinct2 in white sandalwood the vessels are coarsely and sparingly pitted and white translucent2 in red saunders the vessels are coarsely pitted1 bright red and distinct4 ,when studying woods we must consider the width of the medullary rays1 the structure and cell contents of the medullary ray cells2 the structure1 color1 and cell contents of the wood parenchyma2 also the wood fibres4 ,,chapter ,,vi ,,leaves ,leaves collectively constitute the greatest manufacturing plant in the world4 ,most of the food1 clothing1 and medicine used by man is formed as a result of the work of the leaf4 ,the cell contents1 structure1 and arrangement of the different cells of the leaf differ in a marked degree from the cell contents1 structure1 and arrangement of the cells in the other organs of the plant4 ,this accounts for the presence of the large amount of chlorophyll in the leaf1 the presence of stomata1 and the peculiar arrangement of the cells4 ,it should be ascertained if the stomata are above1 even with1 or below the epidermis2 the nature of the epidermal cells1 and1 when present1 the nature of the hypodermal cells2 the number of layers of palisade parenchyma and whether it is present on both surfaces of the leaf1 and the nature of the outgrowths from the epidermal cells4 ,,klip ,,buchu ,the cross-section of klip buchu 7,plate #ajh7 has the following structure3 ,epidermis4 ,the epidermal cells of klip buchu are modified to form papill1 the walls are yellowish white1 and the papillate portion of the cell is nearly solid4 ,hypodermis4 ,the hypodermal cells are never intact because the mucilage contained in the cells swells when placed in water and breaks the thin side walls4 ,upper ,palisade ,parenchyma4 ,the palisade parenchyma is two layers in thickness4 ,the cells of the outer layer are greatly elongated and are packed with chlorophyll4 ,the inner layer of palisade cells is more irregular1 and the cells are much shorter than the cells of the outer palisade layer4 ,illustration3 ,,plate #ajh ,,cross-,,section ,,of ,,klip ,,buchu ,,just ,,over ,,the ,,vein ,a4 ,papillate upper epidermis4 ,b4 ,hypodermal cells with broken side walls1 due to expansion of mucilage contents4 ,c4 ,palisade cells1 showing two cells filled with chlorophyll4 ,d4 ,palisade like mesophyll4 ,e4 ,endodermis4 ,f4 ,vascular strand of vein4 ,g4 ,conducting cells with spirally thickened walls4 ,h4 ,characteristic leaf mesophyll4 ,i4 ,short1 thick palisade cells on the under side of leaf1 just under the vein4 ,j4 ,under hypodermal cells4 ,k4 ,papillate under epidermis4 ,spongy ,parenchyma4 ,the spongy parenchyma cells are branched2 therefore1 large intercellular spaces occur between the cells4 ,under ,palisade ,parenchyma4 ,the palisade cells of the under epidermis are short and broad1 and they contain fewer chlorophyll grains than the upper palisade cells of the upper epidermis4 ,these cells occur only under the veins4 ,under ,hypodermis4 ,the under hypodermal cells are shorter and broader than the upper hypodermal cells4 ,under ,epidermis4 ,the under epidermal cells are modified to form papill which are similar to the papill of the upper epidermis4 ,fibro-,vascular ,bundle4 ,the cells composing the vascular bundle are sieve cells1 vessels1 and fibres4 ,the sieve cells are small and the walls are white and angled4 ,the vessels have thick1 white1 angled walls4 ,the bast fibres are rounded in outline and the walls are thick and white4 ,endodermis4 ,the endodermal cells encircle the fibro-vascular bundles4 ,the cells are large1 thin-walled1 and oval in shape4 ,secretion ,cells4 ,near the edges of the leaf are schizogenous secretion cavities surrounded by thin-walled secretion cells4 ,,powdered ,,klip ,,buchu ,when the leaf is powdered 7,plate #aji71 the cells are quite as characteristic in appearance4 ,the upper epidermal cells 7#a7 have thick-beaded1 yellowish-white walls and papillate outer walls4 ,no stomata occur on the upper surface4 ,the under epidermis 7#b7 with numerous stomata1 is surrounded by the characteristic guard cells4 ,the end walls are beaded as on the upper surface4 ,the palisade cells 7#c7 appear as in the cross-section4 ,the conducting cells 7#d and #d7 are of the spiral and pitted type4 ,the papill 7#e and #e7 are very abundant in the powder and very characteristic4 ,the fragments of the epidermis 7#f7 are also abundant4 ,the mesophyll 7#g7 is characteristic1 as it retains its form when powdered4 ,the fibres 7#h7 are usually associated with the conducting cells2 occasionally they are found free as in the illustration4 ,illustration3 ,,plate #aji ,,powdered ,,klip ,,buchu #a4 ,upper epidermis4 #b4 ,under epidermis4 #c4 ,palisade cells with chlorophyll4 #d and #d4 ,conducting cells4 #e and #e4 ,papill4 #f4 ,fragments of the epidermis4 #g4 ,mesophyll4 #h4 ,fibres4 ,,mountain ,,laurel ,epidermis4 ,the epidermal cells of mountain laurel are occasionally modified1 as unicellular hairs 7,plate #aaj1 ,fig4 #a71 particularly in the region of the veins4 ,the ordinary epidermal cells have thick outer walls and thin inner walls4 ,beneath many of the epidermal cells are large air-spaces4 ,upper ,palisade ,parenchyma4 ,the palisade parenchyma vary from four to five layers4 ,the inner palisade cells are shorter and broader than the outer layer of cells4 ,parenchyma4 ,the parenchyma cells 7,fig4 #d7 are rounded in form and they are arranged in the form of columns which are one cell in thickness above1 but two to three cells in thickness near the under epidermis4 ,between each chain of cells is a larger intercellular space 7,fig4 #f74 ,in a few of the cells are large rosette crystals4 ,under ,epidermis4 ,the under epidermal cells are uniformly smaller than the upper epidermal cells4 ,it is thus seen that mountain laurel leaf has no hypodermal cells2 no spongy parenchyma2 no under palisade cells2 no under hypodermal cells1 and no secretion cavities4 ,,trailing ,,arbutus ,epidermis4 ,the epidermal cells of the trailing arbutus 7,plate #aaa1 ,fig4 #b7 are variable in size4 ,many of the cells are modified1 as guard cells 7,fig4 #a74 ,parenchyma4 ,the parenchyma cells are round and they are compactly arranged 7,fig4 #c7 on the upper side of the leaf1 but on the under side they are arranged in round1 small1 intercellular spaces 7,fig4 #e74 ,in some of the intercellular spaces are rosette crystals 7,fig4 #g74 ,under ,epidermis4 ,the under epidermal cells are smaller than the upper epidermal cells4 ,it will be seen that the structure of trailing arbutus leaf is very simple and that its structure is different from that of klip buchu and mountain laurel4 ,the structure of powdered leaves is very variable1 yet characteristic for a given species4 ,the leaves from the insect flower plant are collected with the stems1 and ground and sold as a substitute for insect flowers4 ,these leaves1 when powdered1 show the following structure 7,plate #aab73 ,illustration3 ,,plate #aaj ,,cross-,,section ,,mountain ,,laurel 7,kalmia latifolia1 ,l47 #a4 ,hair4 #b4 ,epidermis4 #c4 ,palisade parenchyma4 #d4 ,parenchyma4 #e4 ,under epidermis4 #f4 ,intercellular space4 #g4 ,rosette crystal4 #h4 ,chlorophyll4 ,illustration3 ,,plate #aaa ,,cross-,,section ,,trailing ,,arbutus ,,leaf 7,epiga repens1 ,l47 #a4 ,stomata4 #b4 ,epidermis4 #c4 ,parenchyma4 #d4 ,cell with chlorophyll4 #e4 ,intercellular space4 #f4 ,under epidermis4 #g4 ,rosette crystal4 ,both the upper and lower epidermis have stomata 7,figs4 #a and #b71 but they differ in that the surrounding cells of the upper epidermis are wavy1 while the corresponding cells of the under epidermis are similar1 though the under epidermis has many attached hairs 7,figs4 #c and #d74 ,the ,t-shaped hairs form the most abundant element of the powder4 ,they are similar in structure to those found on the scales and stem4 ,fragments of the mesophyll have round cells and contain chlorophyll 7,fig4 #f74 ,the conducting cells are spiral or reticulate4 ,the different cells of the leaf differ greatly in structure1 in amount1 and in arrangement4 ,in uva-ursi1 boldus1 pilocarpus1 eucalyptus1 and chimaphila leaves the outer walls of the epidermal cell is very thick4 ,in uva-ursi leaves this thick wall appears bluish green when viewed under low power of the microscope4 ,in belladonna1 stramonium1 henbane1 peppermint1 spearmint1 digitalis1 and horehound1 the outer wall of the epidermal cells is thin4 ,in witch-hazel1 stramonium1 coca1 phytolacca1 and peppermint there is a single layer of palisade parenchyma on the upper surface only of the leaf4 ,in senna there is one layer of palisade parenchyma on the upper and one layer on the under side of the leaf4 ,in matico and tea leaves there are two layers of spongy parenchyma on the upper side of the leaf4 ,in chestnut leaves there are three layers of palisade parenchyma on the upper side of the leaf4 ,in eucalyptus leaves the entire central part of the leaf1 with the exception of the secretion cells and fibro-vascular bundle1 is made up of the palisade parenchyma4 ,in some leaves no palisade parenchyma occurs4 ,trailing arbutus 7,plate #aaa7 is an example of such a leaf4 ,in stramonium leaves the spongy parenchyma is strongly branched2 in mountain laurel the spongy parenchyma is mostly non-branched and circular in form1 as in trailing arbutus 7,plate #aaa1 ,fig4 #c71 and as occurs in the midrib portion of most leaves4 ,illustration3 ,,plate #aab ,,powdered ,,insect ,,flower ,,leaves 7,chrysanthemum cinerariifolium ,trev41 ,vis47 #a4 ,upper epidermis4 #b4 ,under epidermis showing stoma and hair scar4 #c4 ,cross-section of under epidermis with attached hair4 #d4 ,cross-section of upper epidermis4 #e4 ,hairs4 #f4 ,mesophyll with chlorophyll bodies4 #g4 ,conducting cells4 ,in stramonium and chestnut are found rosette crystals4 ,in henbane1 coca1 and senna are found prisms4 ,in belladonna1 scapola1 and tobacco leaves are found micro-crystals4 ,in most leaves no crystals occur4 ,in witch-hazel and tea leaves stone cells occur1 but in most leaves there are no stone cells4 ,in eucalyptus1 thyme1 jaborandi1 buchu1 rosemary1 and white pine leaves are secretion cells2 while in belladonna1 stramonium cells occur4 ,in senna and coca leaves are crystal-bearing fibres2 most leaves do not have crystal-bearing fibres4 ,in chimaphila and uva-ursi there are no outgrowths from the epidermal cells4 ,in senna1 witch-hazel1 chestnut1 and coca1 numerous non-glandular hairs occur on the epidermis4 ,in tobacco1 belladonna1 henbane1 pennyroyal1 peppermint1 and spearmint both glandular and non-glandular hairs occur on the epidermis4 ,when studying leaves there should be considered the absence or presence of outgrowths and their nature2 the nature of the epidermis and1 when present1 the number of layers of the hypodermis2 the nature of the stoma1 whether raised above1 even with1 or below the level of the epidermis2 the number of layers1 and the distribution1 when present1 of the palisade parenchyma2 the form and amount of the spongy parenchyma2 the absence or presence of secretion cells2 the nature and form of the fibro-vascular bundles1 and the nature and amount of the organic and inorganic cell contents4 ,,chapter ,,vii ,,flowers ,the histological structure of flowers is readily seen in the powder2 therefore1 in studying flowers1 it is not necessary to section the various parts4 ,each part of the flower should be isolated and powdered separately and each separated part studied4 ,in each case the powders will contain surface1 cross-1 and radial sections of the parts powdered4 ,while studying flowers1 special attention should be given to the pollen grains1 to the papill of the petals1 to the papill of the stigma1 and1 in certain flowers1 to the style tissue4 ,in the composite flowers special attention should also be given to the involucre scales1 to the scales of receptacle1 and1 when present1 to the pappus4 ,in addition1 attention must be given to secretion cavities1 as in cloves4 ,,pollen ,,grains ,pollen grains are one of the most characteristic elements found in powdered flowers1 because they are so small that they are not broken up when the drug is milled4 ,the two principal groups of pollen grains are1 first1 those with non-spiny walls 7,plate #aac72 and1 secondly1 those with spiny walls 7,plate #aad71 as shown in the two charts4 ,in lavender flowers the pollen grains have six constrictions of the outer wall4 ,this wall is slightly striated and the cell contents are granular4 ,in clover flowers the pollen grains are mostly rounded in outline1 the wall is uniformly thickened1 and cell contents are coarsely granular4 ,in belladonna flowers the pollen grains terminate in three blunt points4 ,in ,spanish saffron the pollen grains are spherical and the cell contents are granular4 ,illustration3 ,,plate #aac ,,smooth-,,walled ,,pollen ,,grains #a4 ,cloves 7,eugenia caryophyllata1 ,thunb474 #b4 ,santonica 7,artemisia pauciflora1 ,weber74 #c4 ,elder 7,sambucus canadensis1 ,l474 #d4 ,century minor 7,erythra centaurium ,l41 ,pers474 #e4 ,pichi 7,fabiana imbricata1 ,r4 and ,p474 #f4 ,cyani4 #g4 ,lavender 7,lavandula officinalis1 ,chaix474 #h4 ,clover 7,trifolium pratense1 ,l474 #i4 ,belladonna 7,atropa belladonna1 ,l474 #aj4 ,spanish saffron 7,crocus sativus1 ,l474 ,illustration3 ,,plate #aad ,,spiny ,,walled ,,pollen ,,grains #a4 ,anthemis 7,anthemis nobilis1 ,l474 #b4 ,arnica 7,arnica montana1 ,l474 #c4 ,calendula 7,calendula officinalis1 ,l474 #d4 ,cassia flowers4 #e4 ,american saffron 7,carthamus tinctorius1 ,l474 #f4 ,blue malva flowers 7,malva sylvestris1 ,l474 ,the non-spiny-walled pollen grains differ not only in microscopic appearance1 but also in size4 ,clove pollen grains are the smallest1 while ,spanish saffron pollen grains are the largest4 ,,non-,,spiny-,,walled ,,pollen ,,grains ,in cloves the pollen grains show a six-sided1 angled cavity and an outer wall which terminates in three slightly pointed1 narrowly notched portions1 separated by nearly straight walls4 ,in santonica the pollen grains have smooth1 unequally thickened walls1 which are strongly constricted at three points1 the outline resembling three half-circles placed together4 ,in elder flowers the pollen grains appear circular or three-parted4 ,the wall is of nearly uniform thickness1 even at the constricted part of the grain4 ,in century minor the pollen grains show three pronounced restrictions4 ,the wall at these points is very thin4 ,in pichi flowers the pollen grains are either circular or three-sided and three-pointed4 ,inside of each point there is a nearly white pore4 ,in some of the grains the pollen tube has grown out of one of the pores4 ,in cyani flowers the pollen grains are longer than broad and the cell contents appear to be divided into two end portions and an elevated middle portion4 ,,spiny-,,walled ,,pollen ,,grains ,in anthemis the pollen grains have unequally thickened walls constricted in three places4 ,the spines are short1 broad at the base1 and sharp-pointed4 ,in arnica flowers the pollen grains show three light-colored pores and numerous short spines4 ,in calendula flowers the pollen grains show one or more pores1 typically three pores4 ,these pores appear as white spots1 and the wall immediately over the pore is smooth and thinner than the remaining part of the wall2 the spines are very numerous4 ,in cassia flower pollen grains the outer wall is extended into a number of rounded projections which are frequently arranged in sets of fours4 ,in ,american saffron flowers the pollen grains show one1 two1 or three light-colored pores2 the spines are short and broad4 ,in blue malva flowers the pollen grains are spherical and the outer wall extends into numerous spinelike projections4 ,it will be observed that the spiny-walled pollen grains differ greatly in size1 the smallest being the pollen grain of anthemis and the largest being the pollen grain of blue malva flowers4 ,in matricaria are numerous1 greenish-brown1 spiny-walled pollen grains4 ,in anthemis are multicellular1 uniseriate non-glandular hairs with three or four short1 broad1 yellow-walled basal cells and a greatly elongated1 thin1 gray-walled apical cell4 ,in arnica are multiseriated branched hairs of the pappus1 and numerous large1 yellowish1 spiny-walled pollen grains4 ,,stigma ,,papill ,the papill of the stigma of most flowers form a characteristic element even when the flower is powdered4 ,in the case of composite flowers the papill of the disk and ray flowers differ4 ,in ,american saffron the papill of the style differ in a recognizable way from the papill of the stigma4 ,the papill of the stigma of the ray and disk flowers of arnica1 anthemis1 matricaria1 and insect flowers differ greatly4 ,even the papill of the stigma of the ray and disk flowers differ4 ,in all cases observed the papill of the ray flowers are smaller than the papill of the disk flowers4 ,the papill of the stigma of saffron 7,plate #aae1 ,fig4 #c7 are long and tubular4 ,these papill are nearly uniform in diameter1 and the apex is blunt and rounded4 ,the wall is slightly granular in appearance4 ,the papill of the stigma of ,american saffron 7,plate #aaf1 ,fig4 #b7 are short and tubular4 ,each papilla is broadest at the base and tapers to a slender point4 ,the papill of that part of the style which emerges from the corolla 7,plate #aaf1 ,fig4 #a7 are large and curved1 and the walls are very thick4 ,the apex of the papilla is frequently solid4 ,the papill of the stigma of the ray flowers of anthemis 7,plate #aag1 ,fig4 #a7 have thin1 slightly striated walls2 while the papill of the stigma of the disk flowers 7,plate #aag1 ,fig4 #b7 are longer1 the walls are thicker1 and the cell content is denser4 ,illustration3 ,,plate #aae ,,papill #a4 ,arnica ray flowers 7,arnica montana1 ,l474 #b4 ,insect flower disk 7,chrysanthemum cinerariifolium ,trev41 ,vis474 #c4 ,true saffron 7,crocus sativus1 ,l474 ,illustration3 ,,plate #aaf ,,papill ,,of ,,stigmas #a4 ,stigma papill of ,american saffron 7,carthamus tinctorius1 ,l47 from that part of the style that emerges from the corolla4 #b4 ,papill from the upper part of the stigma of ,american saffron4 #c4 ,papill of the stigma of the disk flowers of arnica 7,arnica montana1 ,l474 ,illustration3 ,,plate #aag ,,papill ,,of ,,stigmas #a4 ,stigma papill of the ligulate flowers of anthemis 7,anthemis nobilis1 ,l474 #b4 ,stigma papill of the tubular flowers of anthemis4 #c4 ,stigma papill of the ligulate flowers of matricaria 7,matricaria chamomilla1 ,l474 #d4 ,stigma papill of the disk flowers of matricaria4 #e4 ,stigma papill of the ligulate flowers of insect flower 7,chrysanthemum cinerariifolium ,trev41 ,vis474 ,the papill of the stigma of the ray 7,plate #aag1 ,fig4 #c7 and disk flowers 7,plate #aag1 ,fig4 #e7 of matricaria are similar in structure1 but the papill of the disk flowers are larger4 ,the papill of the stigma of the ligulate flowers of insect flowers 7,plate #aag1 ,fig4 #e7 are tubular2 the walls are striated1 and in each papilla there is a small yellow globule1 while the papill of the disk flowers 7,plate #aae1 ,fig4 #b7 are long and tubular1 and the walls are thick4 ,the papill of the stigma of the ray flowers of arnica 7,plate #aae1 ,fig4 #a7 are very short and tubular4 ,the walls are thin and the cell contents appear as small1 bright-yellow globules1 while the papill of the stigma of the disk flowers 7,plate #aaf1 ,fig4 #c7 are broadest at the base1 the apex is pointed1 and the yellow globules are larger4 ,the solitary hairs are divided into the branched and non-branched hairs4 ,,powdered ,,insect ,,flowers ,the microscopic examination of insect powder is difficult for the reason that there are so many elements to be constantly kept in mind4 ,the parts of the flower which contribute characteristic cells are the stem1 involucre1 ray flowers1 disk flowers1 and the receptacle4 ,in each of these parts there are many different types of cells4 ,there are practically two types of flowers found in insect powder of commerce3 first1 closed or immature flowers1 and secondly1 open or mature flowers4 ,as explained above1 the half-open flowers consist largely of the two above-named varieties4 ,let us first consider the structure of the closed insect flowers as illustrated in ,plate #aah4 ,illustration3 ,,plate #aah ,,powdered ,,closed ,,insect ,,flower 7,chrysanthemum cinerariifolium1 ,trev4 ,vis47 #a4 ,edge of scale4 #b4 ,fibre of scale4 #c4 ,hairs4 #d4 ,upper epidermis of ray flower4 #e4 ,under epidermis of ray flower4 #f4 ,cross-section of ray petal4 #g4 ,parenchyma of ray flowers with crystals4 #h4 ,lobe of disk petal4 #i4 ,filament tissue4 #aj4 ,calyx tissue1 #aa4 ,lobe of stamen4 #ab4 ,pollen4 #ac4 ,papill of stigma4 #ad4 ,secretion cavity with surrounding cells4 #ae4 ,parenchyma of the receptacle4 ,the involucre has many characteristic cells4 ,the more prominent ones seen in the powder are the edge of the scale with the attached hair 7,fig4 #a74 ,these hairs 7,fig4 #c7 are ,t-shaped4 ,the terminal cell is expanded laterally1 and it terminates in two points4 ,connecting the terminal cell with the epidermis are two or three cells which are slightly longer than broad4 ,in the powder the terminal cell is usually attached to fragments only of the supporting cells4 ,fibres of the bracts have thick1 wavy1 porous walls1 and they have a tendency to occur in masses4 ,the upper epidermis 7,fig4 #d7 of the ray-flower petal is prominently papillate4 ,the under epidermis consists of wavy cells without papill4 ,another view of the papill is shown in ,fig4 #f4 ,the parenchyma of the ray flowers 7,fig4 #g7 contain cubical crystals4 ,the lobe of the disk-flower petal 7,fig4 #h7 is papillate at the end1 the terminal cells have thick outer and thin inner walls4 ,the filament tissue 7,fig4 #i7 is composed of nearly square cells4 ,the calyx tissue 7,fig4 #aj7 is made up of thin-walled cells with slightly papillate margins4 ,the lobe of the stamen 7,fig4 #aa7 consists of nearly uniform epidermal cells which are in contact throughout their long diameter1 while the hypodermal cells are thin-walled and angled4 ,the pollen grains 7,fig4 #ab7 are dark yellowish green1 thin1 and the wall does not appear perforated by pores4 ,the papill of the stigma 7,fig4 #ac7 are clustered1 club-shaped1 and nearly white in color4 ,they are usually found detached in the powder4 ,all parts of the pistil contain secreting cells1 but the most conspicuous secreting cavities 7,fig4 #ad7 are those of the ovary4 ,these cavities appear brownish in color and are surrounded by small cells which appear indistinct on account of the great number of superimposed cells4 ,the parenchyma of the receptacle occurs in fragments which have strongly marked porous walls4 ,,open ,,insect ,,flowers ,many of the structures of open insect flowers 7,plate #aai7 are similar to those found in the closed flower4 ,there is practically no difference in the edge of the scale 7,fig4 #a72 or the fibre of the scale 7,fig4 #b72 or the ,t-shaped hairs 7,fig4 #c72 or the upper epidermis of the ray flower 7,fig4 #d72 or the under epidermis of the ray flower 7,fig4 #e72 or the cross-section of the ray petal 7,fig4 #f72 or the lobe of the disk petal 7,fig4 #g72 or the filament tissue 7,fig4 #h72 or the lobe of the stamen 7,fig4 #i72 or the papill of the stigma 7,fig4 #ab72 or the parenchyma of the receptacle 7,fig4 #ae74 ,the difference in structure is found1 first1 in the involucre scales1 which are more fibrous than the scales of the closed flowers2 secondly1 in the pollen 7,fig4 #aa71 which is less abundant than in the closed flower2 it is also lighter in color and usually shows the wall perforated by three pores2 thirdly1 the outer layers of the achene consist of thick1 porous-walled stone cells 7,fig4 #ac71 which occur singly or in groups2 fourthly1 the secretion cavity is broader and darker in color 7,fig4 #ad74 ,these differences enable one at once to distinguish between the closed and open insect flowers4 ,now1 since the half-closed flowers consist almost wholly of a mixture of equal parts of closed and open flowers1 it follows that the elements of these two flowers will be mixed in about equal proportions4 ,thus we are able to distinguish microscopically the three commercial varieties of insect powder--namely1 closed insect flowers1 open insect flowers1 and half-open insect flowers4 ,illustration3 ,,plate #aai ,,powdered ,,open ,,insect ,,flower 7,chrysanthemum cinerariifolium1 ,trev4 ,vis47 #a4 ,edge of involucre scale4 #b4 ,fibres of involucre scale4 #c4 ,hairs4 #d4 ,upper epidermis of ray flower4 #e4 ,under epidermis of ray flower4 #f4 ,cross-section of ray petal4 #g4 ,lobe of disk flower4 #h4 ,filament tissue4 #i4 ,lobe of stamen4 #aj4 ,calyx tissue1 #aa4 ,pollen4 #ab4 ,papill of the stigma4 #ac4 ,stone cells from the achene and cross-section of achene4 #ad4 ,secretion cavity with surrounding cells4 #ae4 ,parenchyma of the receptacle4 ,insect flowers are the most valuable vegetable insecticide known2 yet much of its effectiveness is destroyed by the adulterants which are so readily identified by the compound microscope4 ,,powdered ,,white ,,daisies ,a common adulterant found in open insect flowers is the flower-heads of ,european daisy 7,c4 leucanthemum74 ,examination of powdered flowers exported from ,europe shows that the entire flower-head is ground and mixed with the insect flowers4 ,in the cheaper varieties of open flowers1 only the tubular flowers are added after they have been separated from the heads by crushing and sifting4 ,these tubular flowers so closely resemble the tubular flowers of the true insect flowers that it is practically impossible to distinguish between them macroscopically4 ,the quickest and surest way to identify them is to reduce a portion of the flowers to a fine powder and examine it microscopically4 ,certain structures of the white daisies 7,plate #abj7 are somewhat similar to those found in insect flowers4 ,these structures are the papill of the ray petal 7,figs4 #c1 #e1 and #ac71 the lobe of the disk petal 7,fig4 #ad71 and the lobe of the stamen and the pollen 7,fig4 #h74 ,the differences are as follows3 ,the under epidermis of the ray flowers is composed of wavy cells which are more elongated than the ray flowers of the under epidermis of the ray petal of insect flower4 ,the filament tissue is made up of slightly beaded cells instead of smooth-walled cells4 ,the papill of the stigma are smaller than the papill of insect flowers4 ,the most striking difference is found in the structure of the achene4 ,the epidermal tissue of the achene is composed of palisade cells 7,fig4 #aj71 which in the mature form have thick white walls and scarcely any cavity4 ,these cells swell perceptibly when placed in water4 ,the other striking feature of the achene is the bright red resin masses which occur free in the field4 ,even a small trace of daisies in insect powder can be identified4 ,illustration3 ,,plate #abj ,,powdered ,,white ,,daisies 7,chrysanthemum leucanthemum1 ,l47 #a and #b4 ,scale tissue4 #c1 #e and #ac4 ,papill of petals4 #d4 ,scale tissue4 #f4 ,lobe of ray petal4 #g4 ,filament tissue4 #h4 ,pollen4 #i4 ,papill of stigma4 #aj4 ,palisade cells of achene4 #aa4 ,resin masses4 #ab4 ,parenchyma of receptacle4 #ad4 ,lobe of dish petal4 ,when studying flowers there should be considered the number and structure of pollen grains2 the nature of the papill of the stigma and the petals2 the nature of the hairs of the corolla and calyx1 when present4 ,in the composite flowers we should also consider the structure of the involucre scales1 and1 when present1 the structure of the receptacle scales1 as in the case of anthemus1 and of the pappus hairs1 as in the flowers of arnica1 boneset1 grindelia1 and aromatic goldenrod4 ,,chapter ,,viii ,,fruits ,there is great variation in the structure of fruits1 such a variation1 in fact1 that no one fruit has a structure typical of all the other fruits4 ,each fruit1 however1 has a pericarp and one or more seeds4 ,the amount and structure of the cells forming the pericarp and the seeds of fruits differ in different fruits1 but for each fruit there is a normal amount of1 and a characteristic1 cellular structure4 ,nearly all the important medicinal fruits are cremocarps or umbelliferous fruits4 ,the plan of structure of cremocarps is similar1 but they all have a different cellular structure4 ,the epidermis may be simple or modified as papill or hairs4 ,the secretion cavities may be absent 7conium71 or1 when present1 variable in number--cultivated celery seed has six1 wild celery seed up to twelve1 and anise up to twenty4 ,the vascular bundles may be large or small4 ,the endocarp cells may be two or more layers in thickness4 ,the spermoderm may be thin or thick4 ,the endosperm cells may vary in size and the cell contents may vary4 ,,celery ,,fruit ,the fruit of celery 7,plate #aba71 like other umbelliferous fruits1 is composed of the pericarp and the seed4 ,the pericarp is composed of epicarp cells1 mesocarp cells1 endocarp cells1 and in each rib a vascular bundle4 ,the seed is composed of the spermoderm1 endosperm1 and embryo4 ,each of these parts has a characteristic structure4 ,epicarp4 ,the cells of the epicarp 7,fig4 #a7 are papill and the outer wall is striated4 ,the papill do not show1 however1 unless the cell is cut across the centre1 which is the point at which the papill are located4 ,illustration3 ,,plate #aba ,,cross-,,section ,,of ,,celery ,,fruit 7,apium graveolens1 ,l47 #a4 ,epicarp4 #b4 ,mesocarp4 #c4 ,vascular bundle4 #d4 ,endocarp4 #e4 ,spermoderm4 #f4 ,endosperm4 #g4 ,secretion cavity4 ,illustration3 ,,plate #abb ,,diagrammatic ,,drawing ,,of ,,the #a4 ,cross-section of wild celery seed 7,apium graveolens1 ,l474 #b4 ,cross-section of cultivated celery seed 7,apium graveolens1 ,l474 ,mesocarp4 ,in the rib part of the mesocarp 7,fig4 #b7 is a vascular bundle1 and between the ribs one or more secretion cavities4 ,the vascular bundles are small and are surrounded by irregular-shaped mesocarp cells4 ,the secretion cavities 7,fig4 #g7 are oval in form and the tissue bordering the cavity is reddish brown in color4 ,the mesocarp cells around the secretion cavities are more elongated than the other mesocarp cells4 ,endocarp4 ,the endocarp cells are three layers in thickness4 ,these cells are elongated transversely 7,fig4 #d74 ,spermoderm4 ,the cells of the spermoderm are indistinct1 compressed1 and dark brown in color 7,fig4 #e74 ,endosperm4 ,the endosperm cells 7,fig4 #f7 make up the greater part of the fruit4 ,the walls which are common to two cells are thick1 non-beaded1 and non-pitted1 and the cavities of the cells are filled with aleurone grains4 ,embryo4 ,the embryo cells1 which show only in certain sections1 are similar to endosperm cells4 ,in anise1 hops1 sumac1 and cumin fruits are characteristic hairs4 ,in star anise1 sabal1 allspice1 cubeb1 pepper1 juniper1 buckthorn1 and phytolacca fruits are stone cells4 ,in cubeb1 pepper1 and cardamon are characteristic masses of aggregate starch4 ,in sabal1 allspice1 and juniper are characteristic secretion cells4 ,in all the umbelliferous fruits1 with the exception of conium1 are yellow to brown secretion cavities4 ,in cubeb and pepper is aggregate starch4 ,colocynth contains many single and double spiral vessels4 ,bitter orange contains solitary crystals and spongy parenchyma4 ,when studying fruits we must consider the nature of the epicarp cells--whether simple or modified as papill or hairs2 the form and structure of the mesocarp cells2 the number1 size1 and structure of the vascular bundle2 the size and number of the secretion cells or cavities2 the number of layers and the structure of the endocarp cells2 the number of layers of stone cells--when present2 the color and width of the spermoderm layer2 the structure and cell contents of the endosperm cells2 the nature of the embryo cells1 and the nature of the cell contents4 ,,chapter ,,ix ,,seeds ,seeds are very variable in structure1 so much so1 in fact1 that scarcely any two seeds have a similar structure4 ,it is necessary1 therefore1 when examining seeds1 to compare the structure of the seed under examination with authentic plates or with the section of a genuine seed4 ,the layers of the seed are the spermoderm1 perisperm1 endosperm1 and embryo4 ,in some seeds the spermoderm forms the greater part of the seed2 in others the perisperm is greatest in amount2 in still others the cotyledons make up most of the seed1 as in the mustards4 ,the cells forming these different layers differ in form1 structure1 and number2 therefore it is not difficult to distinguish and to differentiate between the different seeds when viewed as a section or as a powder4 ,almond is studied because it has most of the layers and cells found in seeds4 ,,spermoderm ,the spermoderm is the thin1 brown1 granular-appearing skin of the almond4 ,the layers of the spermoderm are the epidermis1 the hypoderm1 the middle layers1 and the inner epidermis4 ,the epidermis consists of radially elongated1 thick-walled stone cells which occur alone or in groups of two or more1 but seldom as a continuous layer4 ,the upper or outer part of the stone cells is non-porous1 but the inner walls are strongly porous 7,plate #abc1 ,fig4 #a74 ,the hypoderm4 ,the cells forming the hypoderm are compressed1 the wall structure is practically indistinguishable1 and the whole mass is reddish brown 7,plate #abc1 ,fig4 #b74 ,occurring in this brown layer are several vascular bundles 7,plate #abc1 ,fig4 #c74 ,illustration3 ,,plate #abc ,,cross-,,section ,,sweet ,,almond ,,seed #a4 ,epidermis4 #b4 ,hypoderm4 #c4 ,vascular bundle4 #d4 ,middle layer4 #e4 ,inner epidermis4 #f4 ,endosperm4 #g4 ,outer layer of the embryo4 #h4 ,inner layers of the embryo4 ,the middle layers4 ,the cells forming the middle layers 7,fig4 #d7 have thin1 wavy1 light-colored walls which are frequently compressed1 and it is with much difficulty that their outlines are made out4 ,the inner epidermis4 ,the cells forming the inner epidermis are rectangular in form1 and they contain reddish-brown cell contents 7,plate #abc1 ,fig4 #e74 ,,endosperm ,the endosperm4 ,the cells forming the endosperm are large1 rectangular in outline1 usually one layer thick1 and they contain aleurone grains4 ,,embryo ,the embryo4 ,the cells forming the outer layer of the embryo are smaller than the inner layers1 and they are immediately inward from the layer of endosperm cells 7,plate #abc1 ,fig4 #g74 ,the cells forming the greater part of the embryo are large1 rounded1 and they contain aleurone grains and fixed oil 7,plate #abc1 ,fig4 #h74 ,in white and black mustard are characteristic mucilage and palisade cells4 ,in mix vomica1 stropanthus1 and ,st4 ,ignatius's bean are characteristic hairs4 ,in physostigma and kola are characteristic starch grains4 ,in henbane1 capsicum1 stramonium1 lobelia1 and belladonna seeds are characteristic epidermal cells4 ,in areca nut1 colchicum1 saw palmetto1 and nux vomica are characteristic thick-walled1 reserve cellulose cells4 ,in cardamon seed are aggregate starch masses with irregular outlines4 ,in bitter and sweet almond1 linseed1 pepo1 and stropanthus are aleurone grains4 ,in bitter and sweet almonds are stone cells4 ,in linseed1 quince seed1 and in white and black mustard are epidermal cells with mucilaginous walls and contents1 etc4 ,,chapter ,x ,,arrangement ,,of ,,vascular ,,bundles ,having familiarized ourselves with the different types of mechanical and conducting cells1 we shall now consider the different ways in which these cells are associated to form the vascular and fibro-vascular bundles4 ,the simplest form of the vascular bundle occurs in petals1 floral bracts1 and leaves4 ,in these parts the vascular bundle is made up of conducting cells only4 ,in the great majority of cases1 however1 the conducting cells are associated with mechanical cells to form the fibro-vascular bundle4 ,the fibro-vascular bundle is made up of1 first1 the phloem1 which consists of sieve tubes1 companion cells1 bast fibres1 and parenchyma2 secondly1 of the xylem1 composed of vessels and tracheids1 wood fibres and wood parenchyma2 thirdly1 of medullary rays 7restricted to certain types72 and fourthly1 of the bundle sheath 7restricted to certain types74 ,,types ,,of ,,fibro-,,vascular ,,bundles ,there are three well-defined types of the fibro-vascular bundle1 namely1 the radial1 the concentric1 and the collateral types4 ,,radial ,,vascular ,,bundles ,the radial type of bundle is met with most frequently in monocotyledonous roots4 ,in this form 7,plate #aad7 the xylem forms radial bands of tissue which alternate with isolated groups of phloem4 ,the space between the phloem and xylem is filled in with either parenchyma or fibres1 or both4 ,in some cases the vessels of the xylem meet in the centre of the root1 while in other cases the centre of the stem is occupied by pith parenchyma4 ,each bundle is surrounded by parenchyma cells1 and in iris1 calamus1 and veratrum1 rhizomes1 and endodermis1 surrounds the bundles located in the centre of the stem1 consisting of thin-walled 7mechanical7 cells4 ,illustration3 ,,plate #abd ,,cross-,,section ,,of ,a ,,radial ,,vascular ,,bundle ,,of ,,skunk ,,cabbage ,,root 7,symplocarpus ftidus ,l41 ,nutt47 #a4 ,vessels4 #b4 ,bundle sheath4 #c4 ,parenchyma4 #d4 ,sieve cells4 ,illustration3 ,,plate #abe ,,cross-,,section ,,of ,a ,,phloem-,,centric ,,bundle ,,of ,,calamus ,,rhizome 7,acorus calamus1 ,l47 #a4 ,vessels4 #b4 ,sieve cells4 #c4 ,phloem parenchyma4 #d4 ,parenchyma surrounding the bundles4 ,in sarsaparilla root1 the pith is composed of thick-walled1 porous pith parenchyma cells with starch4 ,outside the pith are arranged radial bands of oval vessels which decrease in size toward the periphery4 ,between the ends of these bands occur isolated groups of sieve cells4 ,surrounding the sieve cells and vessels are thick-walled1 angled fibres4 ,external to these cells is an endodermis composed of lignified brownish-colored cells one layer in thickness4 ,,concentric ,,vascular ,,bundles ,there are two principal types of the concentric bundle1 namely1 xylem-centric1 in which the xylem is centric and the phloem is peripheral1 as in veratrum root2 and phloem-centric 7,plate #abe71 in which the phloem is centric and the xylem peripheral1 as in calamus rhizome4 ,,collateral ,,vascular ,,bundles ,there are three types of collateral vascular bundles--namely1 closed collateral1 bi-collateral1 and open collateral4 ,in the closed collateral bundle the phloem and xylem are not separated by a cambium layer1 and in many cases the bundle is surrounded by thick1 angled walled fibres1 as in palm stem4 ,the term closed bundle refers to the fact that there is no cambium between the xylem and phloem1 therefore the bundle is 8closed0 to further growth1 and not to the fact that it is frequently surrounded by fibres which prevent further growth4 ,in podophyllum stem 7,plate #abf7 the xylem portion of the bundle faces the centre of the stem and the phloem portion of the bundle faces the epidermis4 ,the xylem and phloem are separated by a cambium layer1 and both are surrounded by thick-walled angled fibres which are the chief mechanical cells of the stem4 ,this bundle is1 in fact1 mechanically closed1 but not physiologically because a cambium is present4 ,illustration3 ,,plate #abf ,,cross-,,section ,,of ,a ,,closed ,,collateral ,,bundle ,,of ,,mandrake ,,stem 7,podophyllum peltatum1 ,l47 #a4 ,vessels4 #b4 ,sieve cells4 #c4 ,cambium4 #d4 ,fibres4 #e4 ,parenchyma4 #f4 ,intercellular space4 ,illustration3 ,,plate #abg ,,bi-,,collateral ,,bundle ,,of ,,pumpkin ,,stem 7,curcurbita pepo1 ,l47 #a4 ,vessels4 #b4 ,sieve tubes4 ,,bi-,,collateral ,,vascular ,,bundles ,in the bi-collateral vascular bundle 7,plate #abg7 the xylem is in between two groups of phloem--namely1 an inner group and an outer group4 ,in pumpkin stem a bundle occurs in each angle of the stem4 ,the entire bundle is surrounded by parenchyma cells4 ,in an individual bundle the xylem consists of large circular vessels and a phloem containing large sieve cells1 many of which show the yellow porous sieve plates4 ,,open ,,collateral ,,vascular ,,bundles ,in the open collateral bundle 7,plate #ajj7 the xylem and phloem are separated by the cambium layer1 which1 through its divisions1 causes the stem to increase in thickness each year4 ,this type of bundle is characteristic of the stems and roots of dicotyledonous plants4 ,the bi-collateral bundle occurs in many leaves4 ,the xylem in such cases is central1 the phloem strands occupying upper and lower peripheral positions4 ,,index ,abb condenser1 illustration1 #aa ,absorption tissue1 introduction1 #aba tissue of leaves1 #abe ,aerating tissue1 introduction1 #aea ,annular vessels1 illustration of1 #abi ,bark1 of white pine powdered1 description of1 #bej of white pine powdered1 illustration of1 #bea unrossed white pine1 cross-section1 illustration of1 #bdi ,barks1 description of1 #bdh diagnostic structures of1 #bec structural variations of1 #beb ,base sledge microtome1 #ce sledge microtome1 illustration1 #ce ,bast fibres1 #hi branched1 #ib branched1 illustrations1 #ie crystal bearing1 #ij1 #ib description of1 #ajj groups of1 illustrations1 #ajb non-porous and non-striated1 #if non-porous and non-striated1 illustrations1 #aja non-porous and striated1 #if occurrence in powdered drugs1 #ajc of barks1 illustrations1 #ia1 #ic1 #id of klip buchu leaf1 #bfb of ruellia rhizome1 #bbf of ruellia root1 #bbc of ruellia stem1 #bce of spigelia stem1 #bce porous and non-striated1 illustrations1 #ih porous and striated1 #ib porous and striated1 illustrations1 #ig storage function of1 #agi striated and non-porous1 illustrations of1 #ii ,bi-collateral vascular bundles1 description of1 #bih ,buchu stems1 cross-section1 illustration of1 #bdc cross-section1 illustration of1 #bdd powdered1 description of1 #bde powdered1 illustration of1 #bdf ,cambium of pink root1 #bba of ruellia rhizome1 #bbf of ruellia stem1 #bcg of spigelia rhizome1 #bbc of spigelia stem1 #bce ,camera lucida1 #bb illustrations1 #bb ,care of microscope1 #bh ,celery fruit1 diagrammatic drawing of1 #bhg ,cell contents1 #ahb aleurone grains1 #aig aleurone grains1 description of1 #aih aleurone grains1 form of1 #aig aleurone grains1 structure of1 #aig aleurone grains1 tests for1 #aih chlorophyll1 #ahb crystals1 #bjj crystals1 composition of1 #bjj crystals1 micro-1 #bjj crystals1 raphides1 #bjj crystals1 rosette1 #bjj crystals1 solitary1 variation of1 #bje cystoliths1 #baj cystoliths1 forms of1 #baj cystoliths1 occurrence of1 #bae cystoliths1 tests for1 #bae hesperidin1 #aif hesperidin1 test for1 #aif inulin1 #aid inulin1 tests for1 #aid leucoplastids1 #ahc mucilage1 #aid mucilage associated with raphides1 tests for1 #aid mucilage1 tests for1 #aid organic1 #ahb starch grains1 formation of1 #ahc starch grains1 hilum nature of1 #ahh starch grains1 hilum of1 #ahe starch grains1 mounting of1 #ahh starch grains1 occurrence of1 #ahd starch grains1 outline of1 #ahe starch grains1 size of1 #ahe starch grains1 tests for1 #ahh tannin1 #aif tannin1 occurrence of1 #aif tannin1 test for1 #aig volatile oil1 test for1 #aif volatile oils1 #aif ,cell division common to onion root1 #ef ,cell plate1 #ee ,cell sap1 #ec ,cell1 typical1 #ec ,cell wall1 #ec ,chromatin1 #ed ,chromatin granules1 #ee ,chromatophores1 #ec ,chromosomes1 #ee ,closed collateral bundles of mandrake stem1 cross-section illustration of1 #bif ,collateral vascular bundles1 #bie ,collenchyma cells1 composition of walls1 #aji illustrations1 #ajh occurring in catnip and motherwort1 illustrations1 #ajg of ruellia stem1 #bce structure of1 #ajf ,compound microscope1 illustration1 #aj microscope1 mechanical parts of1 #g1 #h microscope of ,robert ,hooke1 illustration1 #h microscope1 optical parts of1 #i1 #aa1 #ab microscopes1 introduction1 #g ,concentric vascular bundles1 #bie ,conducting tissue1 introduction1 #abf ,cork cells1 origin of1 #hh ,cortical parenchyma1 conduction by1 #adg of ruellia stem1 #bce ,cortex1 of pink root1 #bai of ruellia rhizome1 #bbf of ruellia root1 #bba of ruellia stem1 #bce of spigelia rhizome1 #bbc of spigelia stem1 #bcc ,cover glasses1 #dc illustrations1 #dd ,crystal cavities1 #agf cells1 storage function of1 #agi ,cutting sections1 #ca ,cystoliths1 illustrations of1 #bad ,cytoplasm1 #ec ,daisies1 white1 powdered1 description of1 #bhb illustration of1 #bhc ,dissecting microscope1 illustration1 #e needles1 #df needles1 illustration1 #df ,drawing apparatus1 illustration1 #bc ,ectoplast1 #ec ,embryo1 diagnostic structures of1 #bia ,endocarp of celery fruit1 #bhh ,endodermal cells1 illustrations of longitudinal sections1 #aai illustrations of cross-sections1 #aag introduction1 #aaf structure of1 #aaf1 #aah ,endodermis1 of klip buchu leaf1 #bfb of pink root1 #bai of ruellia root1 #bbc ,endosperm of celery fruit1 #bhh of seeds1 #bia ,epicarp of celery fruit1 #bhe ,epidermal cells of leaves1 storage function of1 #agi ,epidermis1 surface deposits of1 #fb of herbaceous stems1 illustrations of1 #aeb of klip buchu leaf1 #bfj of leaves1 illustrations of1 #aee of mountain laurel1 #bfd of pink root1 #bai of ruellia rhizome1 #bbf of ruellia root1 #bba of ruellia stem1 #bce of seeds1 #bhi of spigelia rhizome1 #bbc of spigelia stem1 #bcc of testa1 #fc ,epidermis of trailing arbutus1 #bfd ,equatorial plane1 #ee plate1 #ee ,fibro-vascular bundles1 composition of1 #bib of klip buchu leaf1 #bfb types of1 #bib ,flowers1 diagnostic structures of1 #bhd parts of1 #bgj ,folding magnifier1 #d illustration1 #d ,fruits1 cellular structure of1 #bhe diagnostic characteristics of1 #bhh diagnostic structures of1 #bhh ,glandular hairs of peppermint1 #agh illustrations of1 #afe multicellular1 #afd multicellular1 multiseriate stalked1 #aff multicellular1 multiseriate stalked1 description of1 #aff multicellular1 multiseriate stalked1 occurrence1 #aff multicellular sessile1 #afd multicellular stalked1 #afd multicellular1 uniseriate stalked1 #afd stalked1 illustrations of1 #afg storage function of1 #agh unicellular1 #afd unicellular1 multiseriate stalked1 #afd unicellular sessile1 #afd unicellular stalked1 #afd unicellular1 uniseriate stalked1 #afd ,glandular tissue1 introduction1 #afd ,glass slides1 #dd illustrations1 #dd ,greenough binocular microscope1 #ae illustration1 #ae ,guard cells1 #aea ,hairs1 multicellular1 multicellular non-branched1 illustration1 #ge multicellular1 multiseriate branched1 of ,shepherdia1 #gh multicellular1 multiseriate branched1 #gg1 #hb multicellular1 multiseriate branched1 illustrations1 #gi1 #ha multicellular1 multiseriate non-branched1 #gd multicellular1 uniseriate branched1 illustration1 #gf multicellular1 uniseriate non-branched1 #gb multicellular1 uniseriate non-branched1 illustrations of1 #gc ,hand cylinder microtome1 illustration1 #cd microtome1 #ca microtome1 illustration1 #ca table microtome1 #cd table microtome1 illustration1 #cd ,horehound1 powdered1 description of1 #bcg powdered1 illustration of1 #bch spurious1 powdered1 description of1 #bcg spurious1 powdered1 illustration of1 #bci ,hypoderm of seeds1 #bhi ,hypodermal cells1 of leaves1 storage function of1 #agi illustrations1 #abj structure of1 #aah ,hypoderms1 of klip buchu leaf1 #bfj of ruellia root1 #bba ,illumination for microscope1 #bf ,indirect cell division1 #ed1 #ee ,inner bark of white pine1 #bdh epidermis of seeds1 #bia ,insect flower leaves1 powdered1 illustrations of1 #bfh stems1 description of1 #bda stems1 powdered1 illustration of1 #bdj ,insect flowers1 closed1 powdered1 illustration of1 #bgi open1 description of1 #bhj open1 powdered1 illustration of1 #bha powdered1 description of1 #bgh ,intercellular spaces1 #aeh illustrations of1 #afj1 #afa ,internal phloem1 of spigelia stem1 #bce ,inulin1 illustrations of1 #aie ,karyokinesis1 #ed1 #ee ,klip buchu1 cross-section1 illustration of1 #bfa powdered1 description of1 #bfb powdered1 illustration of1 #bfc ,labeling1 #dg ,latex cavities1 #agf tube cavities1 #agf tubes1 #adb1 #add tubes1 illustration of1 #ade vessels1 illustrations of1 #adf ,leaf epidermis1 #ei illustrations1 #fj1 #fa ,leaf parenchyma1 conduction by1 #aej ,leaves1 diagnostic structures of1 #bfg stomata1 #bfj ,lenticel1 illustration of cross-section1 #aei ,lenticels1 rating function of1 #aeg structure of1 #aeh ,linin1 #ed ,long paraffin process1 #bi ,machine microtomes1 #cb ,measuring cylinder1 #dj illustration1 #dj ,mechanical stage1 #ba stage1 illustration1 #bb tissue1 #hi ,medullary ray1 #aci bundle1 #aci bundle in tangential-section of quassia wood1 #beh cell1 #ada cell1 arrangement of1 in the ray1 #adb cell1 structure of1 #adb cells1 in cross-section of quassia wood1 #bed cells1 in radial-section of quassia wood1 #beh cells1 in tangential-section of quassia wood1 #beh cells1 of ruellia stem1 #bcg ,medullary rays1 illustration of cross-sections of1 #adc illustration of longitudinal section1 #adj in cross-section of quassia wood1 #bed in radial-section of quassia wood1 #bed of pink root1 #bba of ruellia rhizome1 #bbg of ruellia root1 #bbc of spigelia rhizome1 #bbf of white pine bark1 #bej ,mesocarp of celery fruit1 #bhe ,method of mounting specimens1 #da ,micro-crystals1 illustrations of1 #bja lamp1 #bg ,micrometer eye-pieces1 #ba illustrations1 #bj1 #ba ,microphotographic apparatus1 #bd illustration1 #bd ,microscope1 how to use1 #be ,microscopic measurements1 #ai ,microtome1 care of1 #cf ,middle bark of white pine1 #bdh lamella1 #ee layers of seeds1 #bia ,minor rotary microtome1 #cf illustration1 #cf ,mountain laurel1 cross-section1 illustration of1 #bfe ,mucilage cavities1 #agb1 #agf ,multicellular hair1 #gb ,nuclear membrane1 #ee spindle1 #ee ,nucleoli1 #ee ,nucleus1 #ec ,objectives1 illustrations1 #aa ,ocular micrometer1 #ai illustration1 #ai ,oil cavities1 occurrence1 #agh of leaves1 #agh of seeds1 #agh unicellular1 #agb ,open collateral vascular bundles1 description of1 #bih ,origin of multicellular plants1 #eg ,outer bark of white pine1 #bdh ,palisade parenchyma1 conduction by1 #aej ,papill1 #fg illustrations of1 #bge of stigmas1 illustrations of1 #bgf1 #bgg stigma1 description of1 #bgd ,paraffin1 blocks1 #ca embedding oven1 illustration1 #cj ,parenchyma1 aquatic plant1 #aej cells of white pine1 #bdh conduction by1 #add cortical1 illustrations of1 #adh of mountain laurel1 #bfd of trailing arbutus1 #bfd pith1 illustrations of1 #adi ,pericycle of pink root1 #bba of ruellia root1 #bbc ,periderm1 #hj cork1 #hj illustrations of1 #hf of cascara sagrada1 illustrations1 #hd of white oak bark1 illustration of1 #hg parenchyma and stone cells1 #he stone cells1 #he ,permanent mounts1 #da ,pharmacognostic microscope1 illustration1 #ab ,phloem1 centric bundle of calamus1 cross-section1 illustration of1 #bid of ruellia rhizome1 #bbf of ruellia stem1 #bce of spigelia rhizome1 #bbc of spigelia stem1 #bcc ,phloem parenchyma1 conduction by1 #aej of pink root1 #bba of ruellia rhizome1 #bbf of ruellia root1 #bbc of ruellia stem1 #bce of spigelia rhizome1 #bbc of spigelia stem1 #bce ,photosynthetic tissue1 #afc ,pink root1 description of1 #bbg ,pith parenchyma1 conduction by1 #adg of pink root1 #bba of ruellia rhizome1 #bbg of ruellia root1 #bbc of ruellia stem1 #bcg of spigelia rhizome1 #bbf of spigelia stem1 #bce ,pitted vessels1 with bordered pores1 illustration of1 #ace illustrations of1 #acd ,plant hairs1 forms of1 #fg introduction1 #ff ,polar caps1 #ee ,polarization microscope1 #af illustration1 #af ,pollen grains1 #bgj non-spiny-walled1 description of1 #bgc smooth-walled1 illustrations of1 #bga spiny-walled1 description of1 #bgc spiny-walled1 illustrations of1 #bgb ,preparation of specimens for cutting1 #bh ,protoplast1 #ec ,quassia wood1 cross-section1 illustration of1 #bee radial-section1 illustration of1 #beg ,radial vascular bundles1 #bib skunk cabbage root1 cross-section1 illustration of1 #bic ,raphides1 illustrations of1 #bjc ,reading glass1 #d illustration1 #d ,reagent set1 illustration1 #ci ,reagents1 list of1 #ch ,research microscope1 #ac illustration1 #ad ,reserve cellulose1 illustrations of1 #ahj-aha ,reticulate vessels1 illustrations of1 #acc ,root hairs1 #aba1 #abb1 #abe illustration of1 #abc illustration of fragments1 #abd ,roots and rhizomes1 #bai diagnostic structures of1 #bbg ,rosette and solitary crystals1 illustrations of1 #bac crystals1 illustrations of1 #bjd crystals1 inclosed1 illustrations of1 #bjf ,ruellia ciliosa1 ,pursh41 powdered1 illustration of1 #bbi ciliosa1 ,pursh41 rhizome1 cross-section1 illustration of1 #bbe ciliosa1 ,pursh41 stem1 cross-section1 illustration of1 #bcf root1 description of1 #bbg root1 illustration of1 #bbb ,scalpels1 #df illustration1 #dg ,scissors1 #df illustration1 #df ,sclariform vessels1 illustrations of1 #acb ,seeds1 parts of1 #bhi ,secretion cavities1 of celery fruit1 #bhh description of1 #agf illustrations of1 #afi-aga introduction1 #aff lysigenous1 #afh schizogenous1 #afh schizo-lysigenous1 #afh unicellular1 #afh ,secretion cells1 of klip buchu leaf1 #bfb of white pine1 #bdh ,short paraffin process1 #bi ,sieve cells1 of klip buchu leaf1 #bfb of pink root1 #bba of ruellia rhizome1 #bbf of ruellia root1 #bbc of ruellia stem1 #bce of spigelia stem1 #bce ,sieve plate1 #ach illustration of1 #acg ,sieve tube1 illustration of1 #acg tubes1 introduction1 #acf tubes1 structure1 #acf ,simple microscope1 introduction1 #c ,slide box1 #dh box1 illustration1 #dh cabinet1 #di cabinet1 illustration of1 #di forceps1 #de forceps1 illustrations1 #de tray1 #dh tray1 illustration1 #dh ,solitary crystals1 illustrations of1 #bjg-bji1 #baa1 #bab unicellular hairs1 #fi ,special research microscope1 #ad illustration1 #ad ,specimens1 preservation of1 #dh ,spermoderm1 of celery fruit1 #bhh of seeds1 #bhi ,spigelia marylandica1 powdered1 illustration of1 #bbh rhizome1 cross-section1 illustration of1 #bbd root1 cross-section1 illustration of1 #bbj stem1 cross-section1 illustration of1 #bcd ,spindle fibres1 #ee ,spiral vessels1 illustrations of1 #abi1 #acj ,spongy parenchyma of klip buchu1 #bfj ,stage micrometer1 #ai illustration1 #ai ,staining dish1 #dj illustration1 #dj ,standardization of ocular micrometer1 #ai ,starch grains1 illustrations of1 #ahf1 #ahg1 #ahi-aic ,steinheil lens1 #e illustration1 #e ,stems1 diagnostic structures of1 #bcc dicotyledonous1 #bcc herbaceous1 #bcc monocotyledonous1 #bcc ,stomata1 rating function of1 #aea illustrations of cross-section1 #aef relation to surrounding cells1 #aed types of1 #aec ,stone cells1 of ruellia root1 #bbc branched1 #aji branched1 illustrations of1 #aaj description1 in1 #aab introduction1 #aji occurrence1 illustrations1 #aae porous and non-striated1 #aaa porous and non-striated1 illustrations of1 #aad porous and striated1 #aji porous and striated1 illustrations of1 #aac storage function of1 #agh ,storage cavities1 #agf cavities1 illustrations of1 #agg cells1 #agc cells1 cortical parenchyma1 #agc cells1 illustrations of1 #agd cells1 pith parenchyma1 #agc cells1 wood parenchyma1 #agc tissue1 #agc walls1 description of1 #agi ,stored mucilage and resin1 illustrations of1 #age ,surrounding cells1 arrangement of1 #aed ,synthetic tissue1 introduction1 #afc ,temporary mounts1 #da ,testa cells1 #fe epidermal cells1 illustrations1 #fd ,tracheids of pink root1 #bba ,trailing arbutus leaf1 cross-section1 illustration of1 #bff ,tripod magnifier1 #d illustration1 #d ,turntable1 #df illustration1 #dg ,under epidermis of klip buchu leaf1 #bfb epidermis of mountain laurel1 #bfd of trailing arbutus1 #bfd hypodermis of klip buchu leaf1 #bfb palisade parenchyma of klip buchu leaf1 #bfb ,unicellular clustered hairs1 #gb clustered hairs1 illustrations1 #ga non-glandular hairs1 #fi solitary branched hairs1 #gb solitary hairs1 illustrations1 #gj ,upper palisade parenchyma of klip buchu leaf1 #bfj palisade parenchyma of mountain laurel1 #bfd ,vacuoles1 #ec ,vascular bundles1 arrangement of1 #bib occurrence of1 #bib ,vessels1 annular1 #abg and tracheids1 introduction1 #abf in cross-section of quassia wood1 #bed in radial-section of quassia wood1 #bed in tangential-section of quassia wood1 #beh of ruellia rhizome1 #bbf of ruellia root1 #bbc of ruellia stem1 #bcg of spigelia rhizome1 #bbf pitted1 #aca pitted with bordered pores1 #aca reticulate1 #aca sclariform1 #abh spiral1 #abg ,water pores1 aerating function of1 #aea ,watchmaker's loupe1 #d illustration1 #d ,wood fibres1 color of1 #ajd illustrations1 #aje in cross-section of quassia wood1 #bed in radial-section of quassia wood1 #beh in tangential-section of quassia wood1 #beh introduction1 #ajd structure of1 #ajd ,wood parenchyma1 conduction by1 #aej in cross-section of quassia wood1 #bed in radial-section of quassia wood1 #beh of pink root1 #bba of ruellia rhizome1 #bbg of ruellia root1 #bbc of ruellia stem1 #bcg of spigelia rhizome1 #bbf of spigelia stem1 #bce ,woods1 description of1 #bed diagnostic structures of1 #beh ,woody stems1 buchu stem1 description of1 #bdb mature buchu stem1 #bdb ,xylem1 of pink root1 #bba of ruellia rhizome1 #bbf of ruellia root1 #bbc of ruellia stem1 #bcg of spigelia rhizome1 #bbf of spigelia stem1 #bce ,transcriber's ,notes ,the ,table of ,illustrations at the beginning of the book was created by the transcriber4 ,inconsistencies in hyphenation such as 8extra-ordinary0_/8extraordinary0 have been maintained4 ,minor punctuation and spelling errors have been silently corrected and1 except for those changes noted below1 all misspellings in the text1 especially in dialogue1 and inconsistent or archaic usage1 have been retained4 ,page #ec3 8,the outer portion of the nucelus0 changed to 8,the outer portion of the nucleus04 ,page #ed3 8the centre of the nucelus0 changed to 8the centre of the nucleus04 ,page #fb3 8typical forms of arrangement of epidermal calls0 changed to 8typical forms of arrangement of epidermal cells04 ,page #ajd3 8of logwood and santalum rubum0 changed to 8of logwood and santalum rubrum04 ,page #ajg3 8the cross-section of catnip stem 7,nepeta cateria0 changed to 8the cross-section of catnip stem 7,nepeta cataria04 ,page #abj3 8,cross-section sarsaparilla root 7,smilex officinalis0 changed to 8,cross-section sarsaparilla root 7,smilax officinalis04 ,page #aej3 8cells are the narrowest parenchyma cells occuring0 changed to 8cells are the narrowest parenchyma cells occurring04 ,page #aee3 8,upper epidermis of deer tongue 7,trilisia odoratissima0 changed to 8,upper epidermis of deer tongue 7,trilisa odoratissima04 ,page #aga3 8,parenchyma cells with protuding0 changed to 8,parenchyma cells with protruding04 ,page #aic3 8grains of paradise 7,amomum meleguetta0 changed to 8grains of paradise 7,amomum melegueta04 ,page #bcg3 8,marrubium perigrinum1 which is a related species of horehound0 changed to 8,marrubium peregrinum1 which is a related species of horehound04