PLANT CELLS AND LIVING MATTES. 87

Plant Cells and Living Matter.By

Louis Elstoerg, M.O.,of New York.

To botanists biology owed its first knowledge of ultimateStructure and of living matter. The names " cell" and " pro-toplasm" testify to the epoch-making researches of Schleidenand Von Mohl. And in accumulation and classification offurther biological knowledge botanists have taken so prominenta part that even those of us who are interested only in animalmorphology have had to keep some track of the labours ofNageli, Pringsheim, De Bary, Hofmeister, Sachs, Prantl, Stras-burger, and many others. It is all the more remarkable, there-fore, that the investigations carried on during the past decade,which have resulted in proving that all the so-called " cells"constituting animal tissues are interconnected by filaments ofliving matter emanating from these " cells," seem to haveborne no fruit for the study of plants. It was in the hope ofbeing able to repay histological botany for some of the light ithas thrown on animal histology that I engaged in the researches,the account of a few of which I am about to detail.

A small portion of a delicate blade of grass, cut off with apair of scissors, transferred to a slide together with a drop ofdilute glycerine (two parts of pure glycerine and one part ofdistilled water), was examined with a power of 1200 diam. Ihad at my disposal for these examinations two excellent immer-sion lenses, made respectively by Tolles, of Boston, and Ve'riek,of Paris. In some parts, in tvichomes, stomata, air-vessels&c, nothing more could be seen with such amplification thanwith comparatively low powers of the microscope ; the epi-

88 DE. LOUIS BLSBERG.

dermal fields as well as the surrounding frames of celluloseappeared structureless, or at most only very indistinctly granular.The main mass of tissue enclosed by the epidermal system, theparenchyma, presented blunt polygons separated from eachother by a shining narrow rim of cellulose, and containingnumbers of chlorophyll-granules. Some contained only veryfew and very small such granules, surrounded by an extremelydelicate uncoloured reticulum, of which the filaments were ofabout the same breadth as the points of their intersection. Insome polygonal fields there were a number of coarse chloro-phyll-granules interspersed in a network, the threads of whichhad points of intersection that were thickened so as to consti-tute distinct though not green minute granules, while in otherfields there were so many coarse and smaller green granulesthat they nearly completely filled up the polygon. Under allcircumstances, however, the granules, closely focussed, appearedstellate, and were interconnected by means of delicate fila-ments running in large numbers from each granule to all itsneighbours. If of small size a chlorophyll-granule appearedhomogeneous, of a comparatively higher lustre, and of lessintense green colour; larger granules exhibited an indistinctreticular structure in their interior; the largest showed- thereticular structure very plainly, and not infrequently in thecentre a small shining body was observed sending radiatingspokes toward the periphery, inosculating with a thin wall thatenclosed the granule in toto. Toward the apex of the bladethe granules became fewer in number and smaller in size; atthe apex there were no chlorophyll-granules.

In fig. 1 are represented chlorophyll-granules (CHX.) inter-spersed in the reticulum (R) , surrounded by the celluloseframe (c).

These observations show that the vegetable living matterenclosed by the wall of cellulose is arranged in the form of anetwork, and that a similar reticular arrangement exists in thechlorophyll-granules. It is well known that chlorophyll-granules are themselves minute masses of the living matter ofplants, coloured green by a colouring matter, to which the

PLANT CELLS AND LIVING MATTER. 89

name chloropbyll is given. Living matter has been called byHugo von Mohl " protoplasm/' by Lionel Beale " bioplasm,"

FIG. 1.—Cells from blade of grass, showing—CM. Chlorophyll granules.R. Reticulum of protoplasm, and 0. Cell-wall.

and by me, because etymologically more correct, " bioplasson."I am no stickler for new names, but in scientific discussionswe should use, if possible, correct names; and of the foursynonymous designations, viz. living matter, protoplasm, bio-plasm, and bioplasson, I therefore confine myself generally tothe first and last, although the term protoplasm is best knownand by others most used.

In the year 1873, in a communication to the ViennaAcademy of Sciences, entitled " Phases of Living Matter,"Carl Heitzmann first described, in Amoeba, the youthful con-dition of masses of living matter as being constituted by homo-geneous granules, and advanced stages as being characterisedby vacuolation followed by reticulation. These statementswere confirmed as regards vegetable organisms in a paper on" The Structure and Growth of some Forms of Mildew," in the' New York Medical Journal/ November, 1878, by WilliamHassloch, who says lhat the first visible form elements of theplant are homogeneous granules, and the first appearing buds

90 DR. LOUIS ELSBKRG.

compact projections, either globular or elongated, the firstdifferentiation consisting in the occurrence of a central vacuole,while after a certain development has been attained the plantprotoplasm appears in the form of a network.

Many botanists have observed and described reticulatedliving matter, not only when in its naked condition, as plas-modium, as it is called, but also when enclosed in a cellulosewall. Allow me to cite a few examples : Sachs has figured " acell of Zygnema cruc ia tum, with two stellate chlorophyll-bodies which are suspended in the interior of the cell; they areunited by a colourless bridge of protoplasm in which lies anucleus; the rays which form the union with the parietal sacare already nearly colourless in the middle. In each of thetwo chlorophyll-bodies lies a large grain of starch (amplifica-tion 550)," also " forms of the protoplasm contained in cells ofIndian corn (Zea mais) ; A, cells from the first leaf-sheath of agerminating plant, showing the frothy condition of the proto-plasm, i.e. the many vacuoles separated by thin plates; B, cellsfrom the first internode of the germinating plant; the proto-plasm is broken up into many rounded masses in each ofwhich there is a vacuole (b) y these are the so-called ' sap-vesicles.'" Sachs has also figured "parenchyma cells from thecentral cortical layer of the root of F r i t i l l a r i a imperial is ,longitudinal sections, A, very young cells, lying close above theapex of the root, still without cell sap or vacuoles. B, cells ofthe same description about 2 millimetres above the apex of theroot; by the entrance of cell sap the vacuoles s, s, s, havebeen formed, c, cells of the same description about 7 to 8millimetres above the apex of the root," in one of which thereticulum is very plainly seen. Bessey says " in the stamen-hairs of Tradescan t ia Virginica the protoplasm forms arather thick layer over the inner surface of the cell wall, andin some part of this layer the nucleus lies embedded. Fromthe nucleus, and from various parts of the protoplasmic layer,there pass to the opposite side of the cell thicker or thinnerbands and strings, and gives a figure of the same after Hof-meister. Prantl has figured Meristem cells of the stem of

PLANT CELLS AND LIVING MATTER. 91

Vicia faba in which filaments of living matter emanatingfrom the nucleus go to the peripheric layer of living matter,and also hairs from the epidermis of ovary of Cucurbi ta , insome of the compartments of which the reticulum is very dis-tinctly shown with quite low power (x 100).

Heitzmann, the discoverer of the reticulum of living matterand of its continuity throughout the entire animal organism,states in his magnificent work just published, entitled ' Micro-scopical Morphology of the Animal Body in Health andDisease/ p. 57, " My own limited researches enable me toassert that the granules of living matter iu vegetable protoplasmare, as a rule, united in the shape of a reticulum, in the samemanner as in animal protoplasm. Besides, the researches ofW. Hassloch elucidate the identity of both animal and vegetableliving matter in a satisfactory manner. I may add that all cellsof the vegetable organisms are uninterruptedly connected bymeans of delicate offshoots piercing the walls of the cellulose.The granules of amylum are transformed living vegetablematter. The plant in toto is an individual and not composedof individual cells." But demonstration of this statement iswanting. Low powers of the microscope, and even highpowers, show that a less or more thick cloak of cellulose sur-rounds each plante i cell," and separates it from its neighbours.The observations of the chlorophyll-granules and of the interiorof the polygonal cellulose frames of blades of grass herein de-tailed, while they fully bear out the assertions of Heitzmannand Hassloch as to the reticular structure, and perhaps even asto the growth phases, at least so far as dimension is concerned,of masses of living matter of plants, do not advance our know-ledge much further. All my endeavours definitely to determinewhether the plant " cells" are interconnected or not wereunsuccessful with the means I employed in both transparentspecimens and in sections. The inspection, under all sorts ofcircumstances, of the wall of cellulose, although it frequentlygave me the impression that it was faintly granulated, andalthough delicate filaments emanating from the most peripheralchlorophyll-granules were often seen tending towards the wall,

92 DE. LOUIS ELSBBEG.

did not enable me to arrive at a conclusion concerning itsintimate structure.

Francis Darwin has discovered protoplasmic filaments pro-truding from the cellulose investment of the glandular hairson the leaves of Dipsacus sylvestr is ('Quarterly Journal ofMicroscopical Science/ 1877, p. 245). Previously, Hoffman(" Ueber contractile Gefilde bei Blatterschwammen," 'Botan.Zeitung/1853,p. 857,and 1859,p.214) had described contractilefilaments projecting from cell walls in Amani ta (Agaricus)muscaria , and although De Bary has expressed the opinionthat these are not protoplasmic, Darwin believes them to beso (' Quart. Journ. Mic. Sc./ Jan., 1878, p. 74). Later, W. J .Beal (' American Naturalist/ October, 1878, p. 643) describedthreads, but does not say that they are protoplasmic, project-ing from the end of hairs of several plants. Darwin hasobserved filaments of living matter, emanating from the in-terior of plant cells, pierce the cellulose frame. They pro-truded from terminal cells only, and of course showed nointerconnection between neighbouring cells. Such intercon-nection I can now demonstrate.

My first successful observations were made in specimens ofthe flowers of flowering flax (Norimbergia gracilis), and ofthe leaf and stem of the common india-rubber plant (Fieuselastica), and were obtained as follows. The analogy betweenepidermal layers, as well as other parts of a plant, and animalepithelia, led me to the inference that reagents successfullyapplied for elucidating the structure of animal epithelia mightserve for the same purpose in plants. Now, each epithelialbody is a nucleated, reticulated bioplasson mass, enclosed by acontinuous layer of bioplasson and separated from all itsneighbours by a cloak of cement-substance. The cement-sub-stance answers to the cellulose wall of plant cells, and as amemento of Schleideu and his cell doctrine, I would advocatenot only the retention of the term cellulose, but its extensionto animal tissues, i.e. to take the place of the term cement-substance. It is known to histologists that the cement-sub-stance is traversed by numerous conical filaments which by

PLANT CELLS AND LIVING MATTETt. 93

their discoverer, Max Schullze, were termed " thorns orprickles." It is also known that upon applying a 2 per cent,solution of silver nitrate to fresh epithelia, the cement-sub-stance assumes a dark brown hue, and appears perforated bynumerous light transverse lines; while if, on the contrary, aone half per cent, solution of gold chloride be applied to epithe-lium, the bioplasson reticulum in its interior assumes a darkviolet tint, the cement substance remains unstained, and in itMax Schultze's thorns, also coloured deep violet, appear veryplainly. Thus it has been proved that the wall of cement-substance does not completely isolate the single epithelia, butis pierced by bridges of living matter which interconnect allepithelia into one continuous bioplasson mass.

I placed pieces of the flower of " Norimbergia " into a 2 percent, solution of silver nitrate for about half an hour, thenwashed the specimens with distilled water and exposed them todaylight. I found that nitrate of silver does not invariablyaffect the cellulose alone, but sometimes stains also the "cellw-contents; a corresponding general tinction occasionally hap-pens in the case of animal epithelia. Frequently, while thecellulose wall on the inner surface of the flower was compara-tively little coloured by the silver salt and dark granular pre-cipitates filled the spaces between the radiating cellulose off-shoots, the polygonal frames on the outer surface of the flowerwere beautifully stained dark brown by the silver salt; andexamined with Tolle's immersion lens, showed numerousinterruptions in their continuity, as represented in fig. 2,exactly like the light-coloured transverse markings seen incement-substance of animal epithelia under similar circum-stances. Usually the hairs were stained deeply brown; inmany compartments one or several light fields were seen, ofirregular shapes, freely branching; the periphery of such alight-coloured field often looked serrated, and a reticulum pro-ceeding from it pervaded the whole compartment. Thisappearance is shown in fig. 3. In a number of instances Iobserved that the septum separating two neighbouring com-partments was marked by light-coloured lines, as represented in

94 DE. LOUCS ELSBEBG.

fig. 3. The branching light fields were the smaller the nearer

FIG. 2.—Cells from the flower of No-rimbergia, stained with nitrate ofsilver.

FIG. 3.—Hair of flower of Norira-bergia, stained with, nitrate ofsilver.

the compartment was to the apex of the hair; at the end, thewhole hair, as a rule, appeared uniformly dark brown, or con-tained in its interior an extremely delicate, light-colouredreticulum only.

After a one half per cent, solution of gold chloride had beenbrought to bear upon pieces of the flower for about fortyminutes, the wall of cellulose became more distinct althoughnot coloured by the gold salt. In the interior of the polygonalfields, on the inner surface, a scalloped body had made itsappearance; it was slightly retracted from the cellulose frameand offshoots, bordered by a continuous delicate layer, andfilled with a very distinct reticulum in connection with acentral coarsely granular and also reticulated nucleus. Thebordering layer and the reticulum around the nucleus, as wellas the nuclear wall and the intranuclear granules and reti-culum, were of a dark violet colour, just as in animal epithelia

PLANT CELLS AND LTVING MATTER. 95

(see fig. 4). On the outer surface the epidermal bodies

FIG. 4.—Cells from flower of Norimbergia, stained with goldchloride.

exhibited a distinctly reticular structure. The hairs showeddark violet granules and clusters of granules in the interior ofthe compartments; these granules had radiating offshootswhich formed a network, with frequently distinctly granularthickened points of intersection, as represented in fig. 5.There could be no doubt that this was the positive image ofthe structure that was demonstrated by the silver staining in anegative manner as depicted in fig. 3. In some, especially insmall hairs, the dark violet reticulum in the compartment wasvery dense. Frequently, delicate violet filaments pierced thetransverse septa of neighbouring compartments and intercon-nected the reticula and bioplasson formations in their interiors,as seen in fig. 5.

But the most complete proof of the existence of living matterwithin the cellulose walls of plant " cells" I obtained insections of the stems of leaves of the common india-rubberplant (Ficus elastic a), a silver-stained specimen of which

96 DB, LOUIS ELSBEEG.

is represented in fig. 6. The latex oozing out of the stemproved to be composed of a viscid, as if mucous, colour-

PIG. 5.—Hair of flower of Norimbergia, stained with gold chloride.

less liquid, in which were suspended innumerable isolatedgranules of a high lustre, somewhat similar to that of fat;gold chloride staining made the smallest granules appear darkviolet, while the larger were only indistinctly coloured, re-taining their high lustre. Transverse sections of the stem,examined in dilute glycerine, showed chlorophyll-granules andthe reticular structure. The parenchyma of some specimens,especially those treated with strong alcohol, plainly exhibitedthe layer of living matter in the interior of the " cell," whichVon Mohl called " Primordial utricle/'and sacs, more correctly" protoplasmic sac;" and in many cases the bioplasson massshowed the reticular structure. Treatment of gold chloridenot only rendered the network of many bioplasson bodiesdistinctly visible, but in some cases offshoots emanating

""from such bodies were seen to penetrate more or less far intothe cellulose investment; what has been sometimes de-

PLANT CELLS AND LIVING MATTER. 97

scribed by author's, especially in growing tissues, as " inter-cellular spores " and " middle lamellae/' in the cellulose were

*• ,.

FIG. 6.—Cells from petiole of Ficus elastica, treated with silver nitrate.revealed to be in a number of instances accumulations and fila-ments of living matter wedged in between the " plant cells,"very much like the wedges of bioplasson and the medullaryelements which I have found to grow between animal epi-thelia in cases of new growths ("Microscopical Study ofPapilloma of the Larynx/' ' Archives of Laryngology/ March,1880). Treatment with the solution of silver nitrate revealedin the darkened substance of the cellulose light spaces occu-pying the position of such wedges. These light spaces sentoff comparatively broad offshoots parallel to the inner surfacesof the cellulose frame, and innumerable delicate light off-shoots from both the central space and the broad offshootstraversed the brown cellulose in uninterrupted connec-tion with the delicate light reticulum seen here and therewithin the so-called " plant cell." The appearance of thesilver-stained cellulose frame in a portion of such a specimenis accurately reproduced in fig. 6, and the results obtained in

VOL. XXIII. NEW SISR. G

98 DR. LOtJIS ELSBERG.

these specimens I have verified by very numerous other ex-aminations.

My researches demonstrate, and so far as I know, demon-strate for the first time, that the frame of cellulose, analogouslyto the cement substance of animal 'epithelia and the basissubstance of other animal tissues, is pierced by either singlefilaments of living matter or a reticulum with more or lesslarge accumulations .of living matter, interconnecting allneighbouring tissue elements, and that the plant, therefore,like the animal, is one continuous mass of living matter, withinterspaces which contain some non-living material.

The structure of plant tissue may be illustrated by thestructure of hyaline cartilage of animals. For many years itwas believed that cartilage consists of a homogeneous non-living basis substance in which are embedded, at variousdistances a)>art, isolated living cartilage corpuscles—cavtilage-"cel l s" as they were called. TRe more or less convincingobservations made by Heitzmann, and after him by Hertvyig,Thin, Prudden, Spina, and Flesch, have shown this to be amistake; and the results which I obtained in the histologicalexamination of the cartilages of the larynx (published in the'Archives of Laryngology/ October, 1881, and January, 1882),have proved beyond question that hyaline cartilage is a filigreeof living matter, in the meshes of which lumps of basissubstance are embedded. According to the former view car-tilage could be compared to a pudding, in the dough of whicha certain number of ̂ raisins are embedded ; in truth, it is likea framework composed of larger and smaller raisins and bandsand strings of raisin substance, in the meshes or interspacesof which blocks of dough are embedded.

Just so in the tissue of plants, the so-called plant " cells"are connected one with the other, and blocks of cellulose fillup the interstices in the network of living matter.

Not to trespass too much upon the patience of the reader, Imust leave undetailed here the far-reaching consequences ofthe " bioplasson doctrine " for the better understanding of therelations and phenomena of plant life.