Vegetable Cells Research Articles

On the distribution of potassium in animal and vegetable cells

On the distribution of potassium in animal and vegetable cells

The Form and Size of Bacteria

BACTERIA is a generic term that has been applied to an extensive group of single-celled organisms, belonging to the lowest forms of plant life. The bacteria obtain their nutriment from organic matter, either dead or living, and are therefore capable of leading a saprophytic or a parasitic existence. They are amongst the smallest forms of life with which the biologist has to deal, the transverse diameter of the individual cells seldom exceeding a few micro-millimetres, or it may be a fraction of a micro-millimetre. The highest powers of the microscope are consequently necessary for the study of their structure, which is of a simple character, consisting essentially of protoplasm with a containing cellmembrane. The most striking differences are to be found rather in the biological properties of the bacteria as promoters of decomposition, putrefaction and fermentation, or as the originators of morbid processes in plants and animals, than in any distinctive features they possess as vegetable cells. The following account is simply intended to give the reader who is not a specialist a general conception of the main types of these organisms, which form the special study of bacteriology.

The Bacteria which we Breathe, Eat, and Drink

THE surface of the earth is inhabited by bacteria: wherever there is dead organic matter, wherever there are human or animal excreta, wherever decomposition is going on, in stagnating or in flowing water, within our houses and without, bacteria collect. They are so widely distributed that practically everywhere we are surrounded by these minute vegetable cells. From the bacteriological standpoint we live amongst decomposing matter. Without bacteria there is no decomposition or putrefaction; they reduce the organic matter to “dust,” and with the atomised matter they are again carried away by air or water. Dust is laden with bacteria, and since a great part of dust is derived from decomposing matter, it follows that, although we do not realise it, we are living in an atmosphere of decomposition.

III. On the distribution of assimilated iron compounds, other than hæmoglobin and hæmatins, in animal and vegetable cells. Preliminary communication

The question of the presence of iron in the chromatin of animal and vegetable cells and the methods of demonstrating the element in this substance were discussed in a communication to the Royal Society made more than three years ago. Since then I have endeavoured to determine with perfected methods the distribution of assimilated iron compounds in cells of all classes, and have succeeded in obtaining results of which the present communication is an exceedingly condensed and preliminary account. A full account will be published elsewhere.

On the Distribution of Assimilated Iron Compounds, other than Hæmoglobin and Hsematins, in Animal and Vegetable Cells

On the Distribution of Assimilated Iron Compounds, other than Hæmoglobin and Hsematins, in Animal and Vegetable Cells

The Nature and Distribution of Attraction-Spheres and Centrosomes in Vegetable Cells

The theory advanced by Van Beneden has received the support of many of the leading biologists, and has with some additions been quite generally substantiated by investigations. Taking the facts and opinions of those who have studied these bodies, into general consideration, the subject seems to be in the following condition: There is a permanent body in the cell-the attraction-sphere with a centrosome-which is of universal distribution in both plants and animals-at least in all cells which divide by karyokinesis. This body propagates itself by division. As a rule, there seem to be two of these bodies for each resting nucleus, but in some cases only one. They remain constantly ouside of the nucleus. They appear to be the organs which direct nuclear division. It seems that there is a union of the attraction-spheres and centrosomes accompanying the male nucleus with those of the female nucleus during impregnation of the ovum. The bodies migrate and divide, and are thus carried from one cell to the other throughout the entire organism, whether plant or animal.

Studies in Vegetable Biology.-IX. The alleged Existence of Protein in the Walls of Vegetable Cells, and the Microscopical Detection of Glucosides therein.

Studies in Vegetable Biology.-IX. The alleged Existence of Protein in the Walls of Vegetable Cells, and the Microscopical Detection of Glucosides therein.

Protoplasmic Continuity in Plants

IN the very interesting article on “The Continuity of the Protoplasm through the walls of Vegetable Cells,” which appeared in NATURE of June 19 (p. 182), reference is made to the doubt which still exists as to “whether the continuity is maintained from the earliest stages, or is established later.” This point is so important in its physiological bearings, as the article goes on to show, that I may, perhaps, be allowed to state that, with regard to one group of plants, the question appears to be already settled. I allude to the Red Sea-weeds or the Florideæ. The writer of the article makes no mention of these plants, but, as I have described elsewhere (see British Association Report, 1883, p. 547, and Journal of Botany, February and March 1884), many of them exhibit a very notable system of intercellular connections, which, extending over the whole thallus, renders the protoplasm practically continuous from the base of the frond to the extremities of its furthest ramifications. Now in these cases the continuity is certainly maintained from the first, and is due to the mode of cell division by which the thallus is built up. Into the details of this there is no need to enter further than to say that, when the protoplasmic body of a cell divides into two or more portions, these do not become completely separated from one another, but remain connected inter se by strands of protoplasmic material, which grow in thickness with the growth of the cells, and thus maintain the continuity from the earliest stages onward. So far, then, as concerns the Florideœ, I venture to think the physiological import of the phenomena of continuity may be safely discussed on the assumption of its existence ab initio. What that import may be I do not propose to consider, my object being simply to point to the Florideœ as throwing valuable light on the whole subject, and giving some support to the view that “the entire plant or organ is practically one whole—one mass of protoplasm cut up into chambers which communicate with one another, and bounded by a membrane on the exterior.”

Our Book Shelf

THIS is another well-intentioned but unsuccessful attempt to deal in a popular style with some of the more sensational parts of the science of botany. Inaccuracy is again the glaring fault: thus we read on p. 4 that “vegetable cells, in the earlier stages of development, generally approximate to the sphere in form”; on p. 17 that the vessels “serve to convey air through the tissues of the plant,” and “are the lungs of the plant”; and again, on p. 24, that the red and ultra-red rays are those actively concerned in the process of assimilation. Similar inaccuracy may be traced in those of the illustrations which are original; for example, the drawing of Penicillium on p. 60. The frequent production of popular treatises shows that there must be some demand for such books. It is much to be desired that some botanist who is really master of his subject would take the matter up, and write in a popular style a trustworthy account of those parts of the science of botany which are of especial interest to the general public.

The Continuity of the Protoplasm Through the Walls of Vegetable Cells

AMONG the numerous generalisations of modern botany there are perhaps few that promise to have more important consequences than the recent statements to the effect that the protoplasmic contents of the cells of plants are not entirely shut off from one another by the cell-walls, but that arrangements exist of such a kind that more or less delicate strands of protoplasm pass through from one cell to another, piercing the cell-walls either at numerous points at certain thinner spots, or simply here and there.

IV. On the continuity of the protoplasm through the walls of vegetable cells

Since the communications of November 11th, 1882, and April 16th, 1883, the author has been chiefly employed in testing and improving; his methods, and adding to the number of plants in which he has been able to demonstrate the existence of a continuity of the protoplasm between adjacent cells. In certain endosperm cells, e. g ., Bentinckia Conda-panna, where the protoplasmic thr eads traversing the cell walls are particularly well developed, it is possible to see the threads perfectly clearly by merely cutting sections of the endosperm, and mounting them in dilute glycerine. Taking the structure displayed by such a preparation as normal, the author has compared it with the preparations obtained after the action of Chlor. Zinc. Iod. and sulphuric acid. He finds that his method of swelling with Chlor. Zinc. Iod., and staining with Picric-Hoffmann Blue, is in every way perfectly satisfactory, since but little alteration of the structure occurs, and the staining with the Picric-Hoffmann Blue is limited to protoplasm. The sulphuric acid method is in the main unsatisfactory, although it is valuable in the case of thin-walled tissue, where violent swelling must be resorted t o ; and it is also valuable as affording most conclusive evidence of the existence of a protoplasmic continuity in those cases where the protoplasmic processes of pits cling to the pit-closing membrane. He believes, however, that the results obtained Can only be rightly interpreted in the light of the results obtained with Chlor. Zinc. lod. The possibility of seeing the threads depends upon their degree of tenuity and upon the thickness of the pitclosing membrane, and in extreme cases and in w hat are by far the more general cases, the only evidence of such perforating threads is afforded by the general staining of the pit-closing membrane. Every transition between clearly defined threads in the substance of the closing membrane and the mere staining of that structure as a whole occurs. The author has found that in all pitted tissue a pit-closing membrane, which is made evident by staining thin sections with iodine and mounting in Chlor. Zinc. Tod., is uniformly present, and th at open pits do not occur. The continuity of the protoplasm is always established by means of fine threads arranged in a sieve-structure, and not by means of comparatively large processes which the occurrence of open pits would necessitate. He cannot therefore agree with observers whose statements necessitate the existence of such open pits.

XXV. On the continuity of the protoplasm through the walls of vegetable cells

In Professor Sachs’ latest publication the following remarkable passage occurs : “Every plant, however highly organised, is fundamentally a protoplasmic body forming a connected whole, which as it grows on, is externally clothed by a cell membrane, and internally traversed by innumerable transverse and longitudinal walls.” The above statement, both as being the outcome of pure physiological thought, and invested as it is with the authority of so distinguished a botanist, cannot fail to be very striking, on account of its forcible suggestiveness, and any observations which demonstrate an actual continuity in organs of large extent, must be of interest to show the truth of Sachs’ remarks in a sense somewhat more literal than his own.

Some recent Researches on the Continuity of the Protoplasm through the Walls of Vegetable Cells

ABSTRACT Having been for some time engaged in investigating the subject of the continuity of protoplasm through the walls of vegetable cells, it was with no small degree of interest that I read Dr. Elsberg’s paper1 in the hope of finding something that would be of value for my research. In this, however, I was disappointed, and having carefully gone over his paper, and worked through his methods, I resolved to publish my results, believing it to be of extreme importance in a subject such as he treats of, that his statements should, if correct, receive every confirmation and support, or if any mistake had arisen, that such mistakes should as quickly as. possible be rectified.

Observations on Vegetable and Animal Cells; their Structure, Division, and History

In the present paper I propose extending my previous observations “On the Structure and Division of the Vegetable Cell.” I have shown that a nucleolus and nucleolo-nucleus (at Professor Rutherford's suggestion I now propose terming this the endonucleolus) are essential, and in most cases evident, parts of every growing vegetable cell, and that the division of the endonucleolus very probably precedes that of the nucleolus, just as division of the latter undoubtedly precedes that of the nucleus, in all the cases investigated.

2. Observations on Vegetable and Animal Cells; their Structure, Division, and History. Part I., The Vegetable Cell

2. Observations on Vegetable and Animal Cells; their Structure, Division, and History. Part I., The Vegetable Cell

Scientific Serials

THE Quarterly Journal of Microscopical Science contains several papers of importance. The first is by Dr. Klein, entitled “Observations on the Early Development of the Common Trout (Salmo fario),” in which the condition of the blastoderm between the third and thirteenth day is described. The subject is minutely treated, and the bibliography is very complete.—Mr. John Priestley gives a résumé of recent researches on the nuclei of animal and vegetable cells, and especially of ova, and after-wards collates the various statements, indicating their points of divergence.—The investigations of Prof. E. Auerbach and Strasburger, of Dr. Oscar Hertwig and Van Beneden, are those discussed.—M. Edouard Van Beneden's valuable “Contributions to the History of the Germinal Vesicle, and of the first Embryonic Nucleus” contains much of special interest with reference to the relation of the germinal vesicle and the first cleavage nucleus of the egg, especially with reference to the different results arrived at by the author in his study of the ovum of the rabbit, and M. Hertwig's investigations on the echinoderm Toxopneustes lividus.—Mr. H. R. Octavius Sankey gives a new method for examining the structure of the brain, and reviews some points in the histology of the cerebellum. The dye employed for the staining is aniline blue-black, in which sections of fresh brain should remain twelve hours or so, and afterwards be dried.—Dr. James Fonlis gives a lengthy memoir on the development of the ova and structure of the ovary in man and other mammalia. Three plates accompany his paper. The author mainly devotes himself in this communication to the description of the appearances in the ovaries of young kittens, and of the human foetus, with the object of demonstrating, in particular, that whereas the eggs are derived from the germ epithelium, the nutrient cells of the ovum, or the follicular epithelial cells, are derived from the cells of the stroma of the ovary.—Dr. Carpenter, in a paper on the genus Astrorhiza of Sandahl, lately described as Haeckelina, by Dr. Bessels, reintroduces the earlier account of the genus, and figures it.

Recent Researches on the Nuclei of Animal and Vegetable Cells, and especially of Ova

ABSTRACT While much important knowledge of the protoplasmic bodies of cells had rewarded the labours of histological workers, only a few ascertained facts, together with various ill-supported theories, existed respecting the intimate nature and the functions of the nuclei. During the present decade however, much of the energy of research has been directed to repair this deficiency; and the body of fact which we possess concerning nuclei is rapidly gaining in size and solidity. Some of the publications which have assisted in the impulse are those of which an account is now to be attempted.

Notes on Raphides.

ABSTRACT The term Raphides (from φαϕςι, a needle) was first applied by De Candolle to certain needle-like crystals found in the tissues of plants. The term has since been extended by some writers to all crystals found, in plants, whilst others, adhering to the etymology of the word, apply it only to crystals of an acicular form. Schleiden discards the word altogether, and perhaps it would be better to get rid of a term which has neither accuracy nor utility to recommend it. The discovery of crystals in plants is due to Malpighi, who first figured crystals found in a species of Opuntia in his ‘Anatomy of Plants’ The needle-like crystals were afterwards described by Rafu as occurring in the milky juice of the Euphorbiaceæ. Jurin found the same kind of crystals in the leaves of Leucojum verum. Raspail was the first to demonstrate that many of these crystals were oxalate of lime—a fact that Scheele had demonstrated with regard to the crystals found in the roots of the common rhubarb. The most elaborate and complete paper on this subject was published by Edwin Quekett, and appeared in the appendix to the third edition of ‘Lindley’s Introduction to Botany’ in 1839. Since that time various observers have -published observations on this subject. The late Professor John Quekett, in a paper in the ‘Microscopical Transactions,’ showed that many of these crystals had an organic basis. Mr. Rainey, in his ‘Researches on the Mineral Structure of Vegetable and Animal Cells,’ has contributed many observations on the presence of crystalline matters in vegetable cells. In the January number of the ‘Annals of Natural History? Professor Gulliver, in a paper “On the Raphides of British Plants,” says : “It appears to me that these raphides are deserving of more attention than they have yet received both in relation to the structure and economy of vegetables, and as affording a wide, interesting, and scarcely cultivated field of research for the chemical phytologist.” These raphides, he adds, “may also be often useful as diagnostic characters in systematic botany when others are not available ; for example, a mere fragment of one of the Onagraceæ or of the Lemnaceæ may be so surely distinguished simply by its raphides from some of its near allies in other orders, that this fact ought henceforth to be added to the description of the orders just mentioned, independently of its value in other respects.” “Though common in some orders, it is remarkable that the raphides are so rare where they might be most expected, that I have not a single note of their presence in young parts of the stem, leaves, and flowers of British Oxalidaceae, Umbelliferæ, Labiateæ, Euphorbiaceæ, or Polygonaceæ, and even among Crassulaceæ. No crystals were found in Sedum Telephium and S’. acre”

XXXIX.—On the development of vegetable cells

XXXIX.—<i>On the development of vegetable cells</i>