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The World's Greatest Books [Volumes 1-15, 17-20]

Электронная книга - «The World's Greatest Books [Volumes 1-15, 17-20]». Краткое содержание книги:

Антология содержит:
The World's Greatest Books — Volume 01 — Fiction от Неизвестный
The World's Greatest Books — Volume 02 — Fiction от Неизвестный
The World's Greatest Books — Volume 03 — Fiction от Неизвестный
The World's Greatest Books — Volume 04 — Fiction от Неизвестный
The World's Greatest Books — Volume 05 — Fiction от Неизвестный
The World's Greatest Books — Volume 06 — Fiction от Неизвестный
The World's Greatest Books — Volume 07 — Fiction от Неизвестный
The World's Greatest Books — Volume 08 — Fiction от Неизвестный
The World's Greatest Books — Volume 09 — Lives and Letters от Неизвестный
The World's Greatest Books — Volume 10 — Lives and Letters от Неизвестный
The World's Greatest Books — Volume 11 — Ancient and Mediæval History от Неизвестный
The World's Greatest Books — Volume 12 — Modern History от Неизвестный
The World's Greatest Books — Volume 13 — Religion and Philosophy от Неизвестный
The World's Greatest Books — Volume 14 — Philosophy and Economics от Неизвестный
The World's Greatest Books — Volume 15 — Science от Неизвестный
The World's Greatest Books — Volume 17 — Poetry and Drama от Неизвестный
The world's greatest books от Mee, Arthur, 1875-1943, joint editor & Hammerton, John Alexander, Sir, 1871-1949, joint editor & McClure, S. S. (Samuel Sidney), 1857-1949, joint editor
The World's Greatest Books — Volume 19 — Travel and Adventure от Неизвестный
The World's Greatest Books — Volume 20 — Miscellaneous Literature and Index от Неизвестный
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From protozoa or protista to plants and animals the graduation is closer than from magnetised iron to vitalised sarcode. From reflex acts of the nervous system animals rise to sentient and volitional ones. And with the ascent are associated brain-cells progressively increasing in size and complexity. Thought relates to the "brain" of man as does electricity to the nervous "battery" of the torpedo; both are forms of force and the results of action of their respective organs.

Each sensation affects a cerebral fibre, and, in so affecting it, gives it the faculty of repeating the action, wherein memory consists and sensation in a dream.

If the hypothesis of an abstract entity produces psychological phenomena by playing upon the brain as a musician upon his instrument be rejected, and these phenomena be held to be the result of cerebral actions, an objection is made that the latter view is "materialistic" and adverse to the notion of an independent, indivisible, "immaterial," mental principle or soul.

But in the endeavour to comprehend clearly and explain the functions of the combination of forces called "brain," the physiologist is hindered and troubled by the views of the nature of those cerebral forces which the needs of dogmatic theology have imposed on mankind. How long physiologists would have entertained the notion of a "life," or "vital principle," as a distinct entity if freed from this baneful influence may be questioned; but it can be truly affirmed that physiology has now established and does accept the truth of that statement of Locke—"the life, whether of a material or immaterial substance, is not the substance itself, but an affection of it."

RUDOLF VIRCHOW

Cellular Pathology

Rudolf Virchow, the son of a small farmer and shopkeeper, was born at Schivelbein, in Pomerania, on October 13, 1821. He graduated in medicine at Berlin, and was appointed lecturer at the University, but his political enthusiasm brought him into disfavour. In 1849 he was removed to Wurzburg, where he was made professor of pathology, but in 1856 he returned to Berlin as Professor and Director of the Pathological Institute, and there acquired world-wide fame. His celebrated work, "Cellular Pathology as based on Histology," published in 1856, marks a distinct epoch in the science. Virchow established what Lord Lister describes as "the true and fertile doctrine that every morbid structure consists of cells which have been derived from pre-existing cells as a progeny." Virchow was not only distinguished as a pathologist, he also gained considerable fame as an archæologist and anthropologist. During the wars of 1866 and 1870–71, he equipped and drilled hospital corps and ambulance squads, and superintended hospital trains and the Berlin military hospital. War over, he directed his attention to sanitation and the sewage problems of Berlin. Virchow was a voluminous author on a variety of subjects, perhaps his most well-known works being "Famine Fever" and "Freedom of Science." He died on September 5, 1902.

The Cell and the Tissues

The chief point in the application of Histology to Pathology is to obtain recognition of the fact that the cell is really the ultimate morphological element in which there is any manifestation of life.

In certain respects animal cells differ from vegetable cells; but in essentials they are the same; both consist of matter of a nitrogenous nature.

When we examine a simple cell, we find we can distinguish morphological parts. In the first place, we find in the cell a round or oval body known as the nucleus. Occasionally the nucleus is stallate or angular; but as a rule, so long as cells have vital power, the nucleus maintains a nearly constant round or oval shape. The nucleus in its turn, in completely developed cells, very constantly encloses another structure within itself—the so-called nucleolus. With regard to the question of vital form, it cannot be said of the nucleolus that it appears to be an absolute essential, and in a considerable number of young cells it has as yet escaped detection. On the other hand, we regularly meet with it in fully-developed, older forms, and it therefore seems to mark a higher degree of development in the cell.

According to the view which was put forward in the first instance by Schleiden, and accepted by Schwann, the connection between the three co-existent cell-constituents was long thought to be of this nature: that the nucleolus was the first to show itself in the development of tissues, by separating out of a formative fluid (blastema, cyto-blastema), that it quickly attained a certain size, that then fine granules were precipitated out of the blastema and settled around it, and that about these there condensed a membrane. In this way a nucleus was formed about which new matter gradually gathered, and in due time produced a little membrane. This theory of the formation of the cell is designated the theory of free cell formation—a theory which has been now almost entirely abandoned.

It is highly probable that the nucleus plays an extremely important part within the cell—a part less connected with the function and specific office of the cell, than with its maintenance and multiplication as a living part. The specific (animal) function is most distinctly manifested in muscles, nerves, and gland cells, the peculiar actions of which—contraction, sensation, and secretion—appear to be connected in no direct manner with the nuclei. But the permanency of the cell as an element seems to depend on nucleus, for all cells which lose their nuclei quickly die, and break up, and disappear.

Every organism, whether vegetable or animal, must be regarded as a progressive total, made up of a larger or smaller number of similar or dissimilar cells. Just as a tree constitutes a mass arranged in a definite manner in which, in every single part, in the leaves as in the root, in the trunk as in the blossom, cells are discovered to be the ultimate elements, so it is with the forms of animal life. Every animal presents itself as a sum of vital unities, every one of which manifests all the characteristics of life. The characteristics and unity of life cannot be limited to any one particular spot in an organism (for instance, to the brain of a man) but are to be found only in the definite, constantly recurring structure, which every individual element displays. A so-called individual always represents an arrangement of a social kind, in which a number of individual existences are mutually dependent, but in such a way that every element has its own special action, and even though it derive its stimulus to activity from other parts, yet alone affects the actual performance of its duties.

Between cells there is a greater or less amount of a homogeneous substance—the intercellular substance. According to Schwann, the intercellular substance was cyto-blastema destined for the development of new cells; I believe this is not so, I believe that the intercellular substance is dependent in a certain definite manner upon the cells, and that certain parts of it belong to one cell and parts to another.

At various times, fibres, globules, and elementary granules, have been regarded as histological starting-points. Now, however, we have established the general principle that no development of any kind begins de novo and that as spontaneous generation is impossible in the case of entire organisms, so also it is impossible in the case of individual parts. No cell can build itself up out of non-cellular material. Where a cell arises, there a cell must have previously existed (omnis cellula e cellula), just as an animal can spring only from an animal, and a plant only from a plant. No developed tissues can be traced back to anything but a cell.

If we wish to classify tissues, a very simple division offers itself. We have (a) tissues which consist exclusively of cells, where cell lies close to cell. (b) Tissues in which the cells are separated by a certain amount of intercellular substance. (c) Tissues of a high or peculiar type, such as the nervous and muscular systems and vessels. An example of the first class is seen in the epithelial tissues. In these, cell lies close to cell, with nothing between.

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