Plasmodium

“ But here will challenge some twentieth-century Gradgrind: "This is all very pretty from the point of view of abstract science, but what is the practical value of it? The discovery of the plasmodium and its peculiarities has merely shown us the how and the why of a fact that we had known well and utilized for centuries, namely, that quinine will cure malaria." Just listen to what follows. The story of the plasmodium is one of the most beautiful illustrations of the fact that there is no such thing as useless or unpractical knowledge. ”

“ Several have already united to form a common mass, to which others, still free, are converging. The protoplasmic mass thus arising is the plasmodium. The fusion between the protoplasmic bodies of the amoebulae which unite to form it is complete. Their nuclei may be traced for some time in the young plasmodium and no fusion between them has been observed at this stage (20) . As the plasmodium increases in size by the addition of amoebulae the task of following the fate of the individual nuclei by direct observation becomes impossible. ”

“ The reticulum of channels of the plasmodium becomes meanwhile less and less marked. When the whole of the protoplasm is drawn in to the lobes, the circulation ceases. The lobes are the young sporangia. Meanwhile foreign bodies, taken in with the food, are ejected, and the protoplasm secretes on its outer surface a pellicle of mucoid, transparent substance which dries as the sporangia ripen. This invests the young sporangia, and as they rise above the substratum falls together at their bases forming the stalks ”

“ The substance of the plasmodium has about the consistency of the white of an egg; is slippery to the touch, tasteless, and odorless. Plasmodia vary in color in different species and at different times in the same species. The prevailing color is yellow, but may be brown, orange, red, ruby-red, violet, in fact any tint, even green. Young plasmodia in certain species are colorless (as in Diderma floriforme) , while many have a peculiar écru-white or creamy tint difficult to define. ”

“ A single plasmodium may give rise to one or several colonies, at first watery or white, then red, of somewhat varying [Pg 207] shades, then finally umber-brown. These colors were noticed by all the older authors, but very inaccurately; thus a white plasmodium is the basis for Tubifera cylindrica (Bull.) Gmel., a roseate plasmodium for Tubifera fragiformis (Bull.) Gmel., and the mature fructification for Tubifera ferruginosa (Batsch) Gmel. Rostafinski adopted a specific name given by Bulliard, but Batsch has clear priority. ”

“ When we find that a plasmodium of Aethalium, for instance, creeps towards a damp spot, or towards a warm spot, or towards substances that happen to be nutritious, and again creeps away from solutions of sugar or of salt, we seem to be dealing with phenomena every one of which can be paralleled by ordinary phenomena of surface tension279. ”

“ Being an animal, the plasmodium naturally would not grow upon culture-media like the vegetable bacilli and bacteria, and this very fact had delayed its recognition, but raised at once the probability that it must be conveyed into the human body by some other animal. ”

“ Nutrition.—The plasmodium of Badhamia utricularis, advancing over the pilei of suitable fungi, feeds on the superficial layer dissolving the walls of the hyphae (17) . The protoplasm may be seen to contain abundant foreign bodies such as spores of fungi or sclerotium cysts (vide infra) which have been taken in and are undergoing digestion. It has been found experimentally (11) that pieces of coagulated proteids are likewise taken in and digested in vacuoles. On the other hand it has been found that plasmodia will live, ultimately producing sporangia, in nutrient solutions (9) . ”

“ The organism feeds by catching bacteria and other minute particles of organic matter, which are conveyed into the interior of the little mass of protoplasm and digested. The swarm-cells increase in number by division, and ultimately unite in pairs to form a plasmodium, which may, by union with other plasmodia, eventually attain a quite large size. ”

“ When the germinating spores of the fungi, myxomycetes, rupture their walls and become masses of naked protoplasm, they are known as plasmodia. The plasmodium Æthalium septicum occurs in moist places, on heaps of tan or decaying barks. It is a soft, gelatinous mass of yellowish color, sometimes measuring several inches in length.
The plasmodium2 has been chemically analyzed, though not in a state of absolute purity. The table of Reinke and Rodewold gives an idea of its proximate constitution.
Many of the constituents given are always present in the living cells of higher plants. ”

“ Life, however, is not destroyed; its manifestations are only suspended; and if after an indefinite time the apparently dead sclerotium be placed in water, it immediately begins to swell up, the membranous covering of its component cells becomes dissolved and disappears, and the cells themselves flow together into an active amœboid plasmodium. ”

“ Fig. 7.—Plasmodium falciparum. (Malignant tertian) Nonsexual cycle in blood and internal organs of man. Note multiple infections of single red cell. (From MacNeal after Doflein.)
In Romanowsky-stained preparations we see, while the fever is sustained, small hair-like rings, with geometrical outline, with frequently two chromatin dots in one end of the ring and a single red cell often showing two or more of these young rings. The rings are often seen as if plastered on the periphery of the red cells or as if having destroyed a rounded section of the rim of the red cell. ”

“ All are parasites in the cells of particular hosts; their vegetative phase is plasmodial and their spores are formed by the simultaneous breaking up of the plasmodium into an indefinite number of independent cells. ”

“ Plasmodium pale, watery-white or gray; sporangia crowded, ovoid or cylindric, stipitate or sessile, blue-gray, often capped with white; stipe variable in length and structure, where well developed pure white, often flattened, expanded and diaphanous, connate with others through the irregular reticulate or sheet-like hypothallus; columella none; capillitium ample, the lime knots angular or rounded, white connected by hyaline threads; spores in mass black, by transmitted light dark violet, decidedly spinulose, 12–15 μ. ”

“ Physarum sinuosum Wein., Lister, Mycetozoa, 2nd ed., p. 76.
Sporangia distinct or plasmodiocarpous, the plasmodiocarp creeping in long vein-like reticulations or curves, laterally compressed; sometimes distinct and crowded, always sessile. Peridium double; the outer thick, calcareous, fragile, snow-white; the inner delicate, the dehiscence by more or less regular longitudinal fissure. Capillitium strongly developed with abundant white, calcareous granules. Spores smooth, dull violet, 8–9 μ. Plasmodium pale gray, or nearly white. ”

“ The Cytoplasma is a thin skin of colorless plasma covering the entire inner surface of the cell. It is invisible in the living cell but is evident in plasmolysis. In long forms it is thickened at the ends and is condensed at the plasma bridge which frequently connects the two valves and divides the cell into two parts, each containing more or less protoplasm surrounding the vacuole in which are found the cell-sap and certain granules. In some forms, as Meloseira, the cytoplasma includes the entire mass of protoplasm. ”

“ DECH-MANNA COMPOSITION No. 1.
PLASMOGEN (PLASMA PRODUCER.)
Plasmogen—Blood-plasma producer. (The red and white blood-corpuscles are produced by using Eubiogen, XII) .
(a) . Blood-plasma, is the habitat of the red and white blood-corpuscles.
It can be readily understood that the more sanitary a place, the better will be the condition of those who live in it. Therefore, the plasma, (blood-plasma) , must first be made as perfect as possible in accordance with the teachings of science and especially of biology,—a theory which my own experience has proved to be correct. ”

“ The polar and spindle-like radiations visible during the process of karyokinesis, which have already been referred to, and the presence of the centrosome, possibly even during the resting stage of the cell, furnished additional illustrations of differentiation within the cell plasm. In many cells there appears also to be a difference in the character of the cell plasm which immediately surrounds the nucleus and that which lies at and near the periphery of the cell. ”

“ What is this mysterious "living substance" that we find everywhere as the material foundation of the "wonders of life"? Plasm, or protoplasm, is, as Huxley rightly said thirty years ago, "the physical basis of organic life"; to speak more precisely, it is a chemical compound of carbon that alone accomplishes the various processes of life. In its simplest form the living cell is merely a soft globule of plasm, containing a firmer nucleus. ”

“ The process of division goes on in the blood in such a manner that the nuclear rod first divides into two to four single nuclei, and then the whole cell splits up into as many fragments. These cells occur also in fresh pleuritic exudations. After a time the nucleus of these cells becomes free, and the little masses of protoplasm thus cut off are taken up mostly by the spleen substance. The free nucleus likewise shares in the destruction. It is of the greatest importance that these cells, which up to the present have not elsewhere been described, should receive more attention. ”

“ He regarded it as the part of the cell especially endowed with vital energy, whilst the exact function of the nucleus could not be defined. Based upon this conception575 of the jelly-like character of protoplasm, the idea for a time prevailed that a structureless, dimly granular, jelly or slime destitute of organization, possessed great physiological activity, and was the medium through which the phenomena of life were displayed.
More accurate conceptions of the nature of the cell plasm soon began to be entertained. ”

“ For we may here at any moment, by means of the microscope, point out the wonderful fact, first established by Dujardin and Max Schulze, that the formless mucus of the soft plasma-body, this true “matter of life,” is able to secrete the neatest, most regular, and most complicated structures. This secretive skill is simply a result of inherited adaptation, and by it we learn to understand how this same “primæval slime”—this same protoplasm—can produce in the bodies of animals and plants the most different and most complicated cellular forms. ”

“ The Lymphocytes. These are small cells, as a rule approximating in size to the red blood corpuscles. Their body is occupied by a large round homogeneously stained nucleus centrally situated, whilst the protoplasm surrounds the nucleus as a concentric border. Between nucleus and protoplasm there is often found a narrow areola, which doubtless results from artificial retraction. Nucleus and protoplasm are basophil, nevertheless in many methods of staining the protoplasm possesses a much stronger affinity for the basic stain than does the nucleus. ”

“ The existence of this diffusion-preventing or insulating surface-film, the plasma-membrane, is thus a necessary condition of the stability of the living system and hence of the continuance of the life-processes. The living condition is in fact incompatible with marked and permanent increase in surface-permeability. During life the semi-permeable condition is retained; on death there is always a marked increase in the permeability of the plasma-membrane; the cell then undergoes a ready and rapid dissolution or cytolysis, and the constituents serve as food to bacteria. ”

“ Plas′mic, pertaining to plasma, protoplasmic.—ns. Plasmō′dium, composite masses of primitive protozoa, in which numerous units are fused, or in rare cases simply combined in close contact; Plas′mogen, true protoplasm; Plasmog′ony, the generation of an organism from plasma ”

“ Instead of the latter, we find in these cells a roundish, nucleus-like form in the protoplasm, which also takes the nuclear stains, and possibly is to be considered an accessory nucleus. We have received the impression that we have here to deal with a vacuole filled with substance secreted by the cell. In a large series of preparations, it is possible to obtain some elucidation of the development and fate of these appearances. They first appear as point-like granules in the protoplasm, bearing no relation to the cell nucleus; they gradually increase, and acquire a considerable circumference. ”

“ We have seen how little mere form has to do with the essential properties of protoplasm. This may shape itself into cells, and the cells may combine into organs in ever-increasing complexity, and protoplasm-force may be thus intensified, and, by the mechanism of organization, turned to the best possible account; but we must still go back to protoplasm as a naked, formless plasma if we would find—freed from all non-essential complications—the agent to which has been assigned the duty of building up structure and of transforming the energy of lifeless matter into that of living. ”

“ Isn't this a marvellous picture? To see the micro-organism move, evolve and revolve in the midst of normal cells, uncoil and undulate in the fluids which they inhabit, to see them play hide and seek with the blood corpuscles and clumps of fibrin, turn, twist, and rotate as if in a cage, to see these deadly little trypanosomes moving back and forth in every direction displaying their delicate undulating membranes and shoving aside the blood cells that are in their way while by their side the leucocytes, or white corpuscles, lazily extend or retract their pseudopods of protoplasm. ”