Organist

“ Every organism is held together and rendered effective entirely by protoplasm, every organ and part being linked to every other by threads of this substance called nerves. The. life of plants is as dependent upon protoplasm as that of animals, but the protoplasm resides in the cells and controls the vegetative processes. The important fact from our present point of view is that every living organism is an organized mechanism for the storage and voluntary expenditure of energy, and as such does not differ in principle from the chemical products of the inorganic world. ”

“ Now if the compound molecules of the blood, or of an organism considered in the aggregate, have the power of moulding into their own type the matters which they absorb as nutriment; and if they have the power when their type has been changed by disease, of moulding materials afterwards received into the modified type; may we not reasonably suspect that the more or less specialized molecules of each organ have, in like manner, the power of moulding the materials which the blood brings to them into similarly specialized molecules? ”

“ If our ideas concerning the structure of the particular cells of an organ, and the dependence of its functions on this peculiarity, prove correct, then it follows that, as we have already emphasized, each kind of cell must have at its disposal units of its own kind. We may then speak of substances that are "in harmony with" an organ, or even more precisely, "with the cells" ”

“ The idea of an entirely specific structure for each cell of an organ—both from the chemical and physical points of view—is based not only on the supposition that, without such a notion, the special duties and functions of the separate cells of the body would appear incomprehensible, but, above all, on the above-mentioned fact that definite secretions given off by particular organs act constantly and only upon cells of a definite system. ”

“ On the other hand, the morphologist will urge that green plants derive their peculiar powers of metabolism from the possession of very definite cell-organs, namely chromatophores containing chlorophyll; and will argue that living things without such organs must have preceded in evolution those possessing them. The whole dispute is based on the assumption that plant and animal represent the two fundamental modes of metabolism; whereas the study of the Bacteria shows the possibility of many other modes of life. ”

“ It is thought of as a very minute corpuscle of living matter. Thus there are determinants of hairs and scales, pieces of skin, pits, marks, &c. But every determined organ, or part, or “independent region,” is itself in its turn an “organism,” is indeed a system of an infinite number of interrelated component parts, and each of these again is another, down to the individual cells. And each cell is an “organism” in itself, and so on into infinity. Is all this represented in the determinants? ”

“ The Bacteria stand sharply apart from the other forms of life, not only, in many cases, by their divergent methods of metabolism, but by morphological characteristics, such as the definite body-form limited by a distinct envelope, the absence of organs for locomotion other than the peculiar flagella, and, above all, by the lack of any differentiation of the body-protoplasm into nucleus and cytoplasm, as in all true cells of either animal or vegetable nature. ”

“ While the cell is composed essentially of protoplasm, yet it may contain certain so-called cell-products, small quantities of various substances produced by the life-processes of the protoplasm. These cell-products are held in the protoplasmic body-mass of the cell, and may consist of droplets of water or oil or resin, or tiny particles of starch or pigment, etc. The cell cannot be said to be composed of organs, because the word organ, as it is commonly used in the study of an animal, is understood to mean a part of the animal body which is composed of many cells. ”

“ If such a piece protrudes from the level of the toluol it decays, and finally drops down on to the rest of the tissue. The bottle containing the organ should be kept in an ice cupboard.
Bacteria and other living organisms may be prepared exactly in the same way as tissues. Boiling is also resorted to in these cases; and the same rules hold good. It is obvious that organs can be separated into their tissues. The more special the problems to be dealt with, the more does one limit oneself to a very definite tissue. ”

“ Once formed, the organites are arranged side by side, or end on end, into textures or tissues, and these are grouped into organs, every organ being constituted by a collection of tissues, as every apparatus is by a collection of organs, and the organism by the federation of all the parts. We have more than once insisted on the necessity of synthetic interpretation to complete the indications of analysis: which means that no account of vital phenomena is real unless57 it takes in all the co-operant factors, both those of the organism and the medium. ”

“ In this chapter we shall attempt the task among others of showing how, on the basis of the simple physico­chemical structure of the unfertilized egg, the main organ of self-preserva­tion of the organism, the intestine, is formed through the mere process of cell division and growth. Cell division is the most general of the specific func­tions of living matter and it is the basis underlying the differentia­tion of the comparatively simple structure of the egg into a more complex organism. ”

“ Then, too, earlier students had only vague notions of the actual structure of a living organism. Beginning with the earliest idea that a plant or an animal exists as a unit organism, to be studied as such, biological science progressed, first to the recognition and study of the individual organs which are contained within the organism; then to the tissues which make up these organs; then (with the coming into use of the microscope as an aid to these investigations) to the cells of which the tissues are composed; then to the protoplasm which constitutes the cell contents ”

“ The bacteria, like other kinds of living organisms, possess a definite form and shape. They are the simplest in structure of all the plants, the individual organism consisting of a single cell. The larger and more highly organized forms of life are made up of many microscopic cells, and the life of the individual consists of the work of all the cells. ”

“ In addition to the limit thus imposed upon the cytoplasmic area which can be effectually controlled by the nucleus, and the necessity for a minimum surface area to the protoplasmic mass, the advantages of the more or less complete subdivision of the living substance into—as far as their metabolism is concerned—semi-autonomous units, is indicated by the mechanical support derived from the specialized cell walls and turgescent cells of the plant, and the intercellular secretions of the animal tissues. ”

“ In the first place, the extremely small size and isolation of the vegetative cells place the protoplasmic contents in peculiarly favourable circumstances for action, and we may safely conclude that, weight for weight and molecule for molecule, the protoplasm of bacteria is brought into contact with the environment at far more points and over a far larger surface than is that of higher organisms, whether—as in plants—it is distributed in thin layers round the sap-vacuoles, or—as in animals—is bathed in fluids brought by special mechanisms to irrigate it. ”

“ The second and higher stage is the cell, which is already divided or differentiated into nuclear matter and cellular matter. We comprise both kinds—the cytodes and the cells—under the name of plastids (“formative particles”) , because they are the real builders of the organism. However, these cytodes are not found, as a rule, in the higher animals and plants; here we have only real cells with a nucleus. Hence, in these tissue-forming organisms (both plant and animal) the organic unit always consists of two chemically and anatomically different parts—the outer cell-body and the inner nucleus. ”

“ A certain analogy may be observed between the organs of life in plants and those of animals. If, for example, we take a thin transverse slice of the stem of any plant, and cut across that stem and immerse it in pure water, and place it under a microscope, we shall find that it consists principally of cells of various shapes according to particular plants. The cells, which are generally very minute, are the elementary organs, and although the cell may vary in form, in its essential nature it is always the same. ”

“ A special place is occupied, at least qualitatively, by all those substances which, like the units of the different organic nutritive and tissue materials—as well as the inorganic constituents, the salts, water, &c.—exhibit no specific structure, and which are common to the most different kinds of cells, as well as to the blood and lymph, as intermediate and final products. ”

“ And of like natures are the criticisms which must be passed on the generalization, that cells are the morphological units of organisms. To continue the simile, the truth turns out to be, that the primitive clay or protoplasm out of which organisms are built, may be moulded either directly, or with various degrees of indirectness, into organic structures. The physiological units which we are obliged to assume as the components of this protoplasm, must, as we have seen, be the possessors of those proclivities which result in the structural arrangements of the organism. ”

“ The staggering difficulties in imagining such a possibility are not merely on the chemical side—e. g., the produc­tion of proteins from CO2, and N—but also on the physical side if the necessity of a definite cell structure is considered. We shall see in the sixth chapter that without a structure in the egg to begin with, no forma­tion of a complicated organism is imaginable; and while a bacterium may have a simple structure, such a structure as it possesses is as necessary for its existence as are its enzymes. ”

“ Inasmuch as the idea of an organic cell, as now adopted by histologists, rests on the presence of two different essential parts in this elementary organism, the internal cell and the external protoplasm, we must distinguish also two different kinds of elementary organisms: germless cytods, as moners for example, and the real germ-inclosing cells, which originate from the former by secreting in the interior of the small mass of protoplasm a true germ or nucleus. ”

“ Our progress in the field of the chemistry of the different kinds of cell units, and of their nutritive bases, has brought us nearer to this objective, but a large part of the road lies before us yet, before we shall obtain such an exact knowledge of the composition of certain albuminous substances, such as phosphatides and nucleoproteids, &c., as to be able to properly appreciate differences of configuration, as well as differences of structure. ”

“ The organs of secretion, however, may in a certain respect be considered as a repetition of the organs of respiration, since the evaporation and secretion of gases form a prominent part in the process of respiration. The plant develops, besides the organs of general assimilation and secretion, those of generation: a similar development takes place in the animal also, and precisely at the point where the germ of the fruit is developed in the plant, at a point which is therefore analogous to the insertion of the stamen in the flower ”

“ The cell, which consists of protoplasm and a nucleus, is an elementary organism, that, by itself, or in combination with other cells, forms the basis of all animal and vegetable organisation. In minute structure it is so extraordinarily complicated that its essential constitution (its micellar or molecular structure) eludes our observation. It is a medley, composed of numerous, chemically distinct particles that may be divided into two groups, organised and unorganised. ”

“ The whole organization of any multicellular organism is composed of two entirely different kinds of cells—namely, the germ-cells, or those which have to do with reproduction, and the somatic-cells, or those which go to constitute all the other parts of the organism. Now, the somatic-cells, in their aggregations as tissues and organs, may be modified in numberless ways by the direct action of the environment, as well as by special habits formed during the individual lifetime of the organism. ”

“ The cells of which all plants and animals consist increase in numbers by the division of [Pg 10] each cell into two cells through the formation of a division wall across the cell. The new cells divide and the plant or animal continues to grow. The same cell division occurs in the bacteria but since the bacteria are single celled, division of the cells means an increase in numbers rather than growth as in the higher forms of life. ”

“ The elementary unit of plant structure, as of animal structure, is the cell. Within it or its modifications all the vital phenomena of which living organisms are capable have their origin. Upon our knowledge of its minute structure or cytology, combined with a study of its physiological activities, depends the ultimate solution of all the important problems of nutrition and growth, reception and conduction of stimuli, heredity, variation, sex and reproduction. ”

“ The animal cell, in its most complete form, is comparable in most parts of its structure to that of the plant, but differs from it in the entire absence of the 'cellulose wall' or of anything that represents it, the cell-contents being enclosed in only a single limitary membrane, the chemical composition of which, being albuminous, indicates its correspondence with the primordial utricle. ”