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CELLS. 



CELSIA. 



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forms of plants, and the less organised tissues of animals, as cartilage, 

 up to the elongated Teasels of the plant, and the irregular cells of 

 bone or areolar tissue in animals. The animal kingdom presents by 

 far the greatest variety in this respect, and so great are the changes 

 that some of the animal cells undergo, that the terms Metamorphoses 

 or Transformations have been applied to these changes. As examples 

 of these cells we may quote the horny scales of the epidermis, of 

 the hair and the nails, and the laminated pavement, epithelium in 

 which the cells are flattened, polygonal, or fusiform, and the cell-wall 

 is fused into one mass with the cell-contents ; the contractile fibre- 

 cells of the smooth muscles ; the tubulea of the lens ; the prisms of the 

 enamel; the various forms of bone-cells ; and the transversely striated 

 cells of muscular fibre. 



All cells originate or are produced in the same way. Either they 

 are developed free in vegetable or animal fluids, or they are produced 

 in the interior of preceding cells. In all cases they originate in con- 

 nection with a substance called protein, which exists in cells, either 

 in the form of a small dark spot called a nucleus, or cytoblast, in the 

 interior of which is a nucleolus, or of an expansion on the interior of 

 the cell, when it is called the primordial utricle. Free cell-development 

 nas been observed to take place in plants, in saccharine and other 

 liquids about to undergo the fermentation process, and amongst 

 animals in the chyle, blood, and lymph. The exact mode of the 

 development of cells under these circumstances has not been 

 accurately observed, and the particles or granules of proteinaceous 

 matter from which they are supposed to originate have not yet been 

 proved to have had their origin independent of other cells. The most 

 common form of cell-development is that in which the cell grows 

 around or from the nucleus or primordial utricle. In the animal 

 kingdom the development of the cell more frequently takes place 

 around the nucleus, whilst in the vegetable kingdom its origin is 

 more frequent from the folding in or contraction of the primordial 

 utricle upon itself, by which means two cells originate in one. 



Besides the development of cells around the nucleus and round the 

 investing membrane, or primordial utricle, within the walls of the 

 cell, a multiplication of cells frequently takes place by division of the 

 whole cell. This takes place in many of the lower forms of animals 

 and plants [PROTOZOA], and also in the red blood-corpuscles of the 

 erabryoes of birds and mammalia, and in the colourless blood-corpuscles 

 of the tadpole. It is probable that further observation will extend 

 our knowledge of this mode of cell-multiplication. 



One of the highest problems for the physiology of the present day 

 to solve is, the efficient causes of the phenomena of cell-development. 

 The following propositions have been laid down by Kolliker as an 

 attempt to follow up Schwann's idea of the analogy between chemical 

 changes in inorganic bodies and those which occur in cells : 



1. The nucleus of the cell arises in the first place as a precipitate 

 in an organisable fluid, and afterwards becomes consolidated in such 

 a manner that a special investment and contents with a nucleolus 

 appear. Its development may in this case be compared to that of 

 inorganic precipitates, yet the constantly globular figure and size of 

 the nuclei which are just formed, indicate some essential though not 

 yet recognised condition peculiar to them. 



2. In the development of cells by division the cell-nucleus plays 

 exactly the same part which was previously ascribed to the 

 uucleolus, and the occurrence of the formation of cells in this 

 manner demonstrates that chemical conditions are not necessarily 

 concerned therein. 



3. In cell-development around portions of contents, and in the 

 cleavage process, the nuclei also operate as simple centres of attrac- 

 tion upon a certain mass of blastema, and then follows the formation 

 of a membrane upon the surface of this mass, which is most simply 

 understood as a condensation of the blastema. 



4. In the cell-development directly around the nucleus the invest- 

 ment with blastema is wanting, and the nucleus develops the mem- 

 brane immediately around itself. 



From what has been previously said, it will be seen that the cells 

 are the active seat of the functions of both animals and plants, and 

 the most conspicuous results of organisation takes place in conse- 

 quence of their agency. They not only constitute the mass of the 

 body, but by their agency alone all the special secretions and products 

 of individual plants and animals are formed. The food is conveyed 

 into the body by cells, the blood of animals in charged with cells, and 

 the functions of locomotion and sensation are carried on by the agency 

 of cells. Nor are these last functions peculiar to the animal kingdom. 

 Contractility and sensibility seem to be the property of the substance 

 (protein) of which the nucleus and primordial utricle are composed. 

 To this substance Mr. Huxley proposes to give the name Endoplast, 

 and thus concludes a lecture on the identity of structure of plants 

 and animals : 



" In both plants and animals then there is one histological element, 

 the Endoplast, which does nothing but grow and vegetatively repeat 

 itself ; the other element, the periphistic substance (the cell membrane) 

 being the subject of all the chemical and morphological metamorphoses, 

 in consequence of which specific tissues arise. The differences between 

 the two kingdoms are, mainly, 1, that in the plant the Endoplast 

 .ni'l, OH thn primordial utricle, attains a large comparative size; 

 while in the animal the Endoplast remains small, the principal bulk 



of its tissues being formed by the periplastic substance ; and, 2, in 

 the nature of the chemical changes which take place in the periplastie 

 substance in each case. This distinction however does not always 

 hold good, the Ascidians furnishing examples of animals whose peri- 

 plastic substance contains cellulose. 



" The plant then is an animal confined in a wooden case, and 

 nature, like Sycorax, holds thousands of ' delicate Ariels ' imprisoned 

 within every oak. She is jealous of letting us know this ; and among 

 the higher and more conspicuous forms of plants reveals it only by 

 such obscure manifestations as the shrinking of the Sensitive Plant, 

 the sudden clasp of the Dioncea, or, still more slightly, by the pheno- 

 mena of the Cydoiis. But among the immense variety of creatures 

 which belong to the invisible world she allows more liberty to her 

 Dryads ; and the Protococci, the Volvox, and indeed all the Algae, are 

 during one period of their existence as active as animals" of a like 

 grade in the scale. True, they are doomed eventually to shut them- 

 selves up within their wooden cages and remain quiescent ; but in 

 this respect they are no worse off than the Polype, or the oyster 

 even." 



For further information on the subject of Cells, see the articles 

 ANIMAL KINGDOM ; BLOOD ; HISTOLOGY ; BOTANY ; CILIA ; TISSUES, 

 VEGETABLE ; TISSUES, ANIMAL. 



(Sharpey, in Quain's Elements of Anatomy ; Kolliker, Handbook of 

 Human Histology, translated for the Sydenham Society by Huxley and 

 Busk ; Carpenter, Manual of Human Physiology ; Principles of Phy- 

 siology ; Mohl, On t/te Vegetable Cell, translated by Henfrey ; Schleiden, 

 Principles of Scientific Botany, translated by Lankester ; Schleideu, On 

 Phylogenesis ; Schwann, On tlie Identity of Structure in Plants and 

 Animals, translated by H. Smith for the Sydenham Society ; Quekett, 

 Lectures on Histology; Hassall, Microscopic Anatomy of the Human 

 Sody ; Todd and Bowman The Physiological Anatomy and Physiology 

 of Man ; Quekett, Catalogue of the Histological Series in the Museum 

 of the Royal College of Surgeons, London ; Quarterly Journal of Micro- 

 scopical Science; and Transactions of Microscopical Society, vol. i.) 



CELLULAR TISSUE. This name has been given to certain forms 

 of both animal and vegetable structures. In the animal kingdom it 

 has been applied to that tissue which is found investing and forming 

 the basis of all others. As however this tissue is not more strictly 

 cellular than any of the other structures of the body, and is even less 

 cellular under the microscope than many others, this term has been 

 abandoned by recent anatomical writers, and the term Areolar Tissue 

 substituted. [ABEOLAR TISSUE.] The term Cellular Tissue is still 

 made use of by botanists to distinguish those parts of plants in 

 which the cells have not united together to form continuous tubes 

 or vessels. The whole of the tissues of plants like those of animals 

 originate in cells, and it is somewhat difficult to fix the limitations 

 of this term. [CELLS ; TISSUES, VEGETABLE.] 



CELLULARES, a term applied to the large class of plants, which 

 have also received the names Cryptogamia, Acotyledons, Agama, 

 Ejcembryonattf, and Acrogens. [AcROGENs.] It was especially adopted 

 by De Candolle, the primary divisions of whose system consisted of 

 Vasculares, or plants with both Cellular and vascular tissue, and 

 Cellulares, or plants furnished with cellular tissue only. These distinc- 

 tions do not hold good anatomically, and since the more prominent 

 recognition of the fact that cellular and vascular tissue originate 

 alike in the cell, and are but forms of the same substance, these 

 distinctions have been less regarded. 



CELLULARIA. [CELLARLEA.] 



CELO'SIA a genus of plants belonging to the natural order 

 A marantaceoj, comprehending the flowers which gardeners call Cocks- 

 combs, on account of the crested flattened appearance of their 

 inflorescence. The calyx consists of 5 narrow sharp-pointed sepals, 

 surrounded by some bracts of the same shape and colour as them- 

 selves. The stamens are 5, and united into a plaited cup. The 

 capsule is membranous, 1 -celled, opens by a transverse fissure, and 

 contains two or three seeds. The leaves are always alternate. Only 

 two species are cultivated, namely C. criitata and C. coccinea. 



C. crittata, the Common Cockscomb, is said to be a native of the 

 East Indies, but it is more probable that it came originally from either 

 Japan or China, for it is only seen in gardens in the East Indies. It 

 varies in regard both to stature and colour, some of the sorts being as 

 much as two feet high, while others do not exceed six inches ; in 

 colour it is seen with deep blood-red, purple, and yellowish-white 

 combs, the latter however is seldom cultivated now. 



C. coccinea is by no means so striking a plant as the last in appear- 

 ance, for it forms little or no crest, but it bears its flowers in panicled 

 spikes. It also is said to be a native of the East Indies, and varies 

 with purple and silvery or yellow flowers. 



Nothing can be more easy of cultivation than these flowers ; and 

 they are capable of being brought to an extraordinary size by good 

 management. 



CELSIA (named by Linnaeus in honour of Olaf Celsius, D.D., 

 professor of Greek, and afterwards of Theology, in the University of 

 Upsal), a genus of plants belonging to the natural order Solanaceee. 

 It has a 5-parted calyx, a rotate 5-lobed corolla, 4 perfect stamens, 

 didynamous, bearded. All the species are herbs with simple or pinnate 

 leaves, the flowers disposed in loose terminal racemes, each rising from 

 the axil of a bract or small leaf. 



