The Florey Lecture, 1982 Discovery: accident or design?

1982 ◽  
Vol 216 (1204) ◽  
pp. 253-265 ◽  
Keyword(s):  
Electron Microscope ◽  
Muscle Fibre ◽  
19Th Century ◽  
Surface Membrane ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Personal Factors ◽  
Local Activation ◽  
Microscope Technique ◽  
The 19Th Century

The lecturer reviews the extent to which his own experiments on muscle have followed the course intended when they were planned. His observations on changes in the striation pattern were designed to reinvestigate the formation of ‘contraction bands’, repeatedly observed in the 19th century but neglected more recently. This phenomenon was indeed seen during active shortening,. but the most important outcome consisted of two quite unexpected observations which suggested the existence of a sliding-filament system. Experiments on local activation were planned on the hypothesis that activation was conducted inward from the surface membrane along the Z line. This was apparently confirmed in the first experiments, on fibres from frog muscle, but experiments on muscle fibres from other animals, together with improvements in electron microscope technique, showed that this was a coincidence and that the Z line as such is not involved. Investigation of the transient changes of tension when a stimulated muscle fibre is suddenly shortened required a series of exploratory measurements before a useful hypothesis could be formulated. Some personal factors that have motivated scientists, including Lord Florey himself, are discussed.

The spindle and extrafusal innervation of a frog muscle

1957 ◽  
Vol 146 (924) ◽  
pp. 416-430 ◽  
Keyword(s):  
Muscle Fibre ◽  
Short Distance ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Intrafusal Muscle ◽  
Intrafusal Fibre ◽  
Unmyelinated Axons ◽  
Intrafusal Fibres ◽  
Break Up ◽  
Tonic System

In the frog muscle, ext. long. dig. IV, there are two or three spindle systems. Each consists of a bundle of intrafusal muscle fibres with two, three or four discrete encapsulated sensory regions distributed in mechanical series along it. A sensory region is usually comprised of the coiled branches of one afferent axon. These embrace the intrafusal fibres and ultimately form long fine varicose endings on or near them. The intrafusal striations appear to be lost for a short distance within the sensory region, and in this region the intrafusal fibre nuclei crowd together. The ‘small’ extrafusal efferents break up into trusses of fine unmyelinated axons and terminate as ‘grape’ end-plates, several of which can occur on the same muscle fibre. This is the ‘tonic’ system. The ‘large’ extrafusal efferents terminate as ‘Endbiischel’ end-plates on muscle fibres not supplied by grape endings. This is the ‘twitch’ system. Both ‘grape' and ‘twitch’ end-plates occur on the intrafusal bundle (probably on separate fibres) between the sensory regions. They are supplied by branches of ‘small’ or ‘large’ axons respectively, which also innervate extrafusal fibres. Thus like the extrafusals the intrafusal bundle is composed of ‘tonic’ and ‘twitch’ muscle fibres. This situation contrasts with that of the mammal, where extrafusals are exclusively ‘twitch’ fibres and intrafusals ‘tonic’.

Microscopy of Muscle in the 19th and 20th Centuries

2000 ◽  
Vol 6 (S2) ◽  
pp. 90-91
Author(s):  
Andrew F. Huxley
Keyword(s):  
Refractive Index ◽  
19Th Century ◽  
Light Microscope ◽  
Striated Muscle ◽  
High Refractive Index ◽  
Muscle Fibres ◽  
Positive Image ◽  
Ordinary Light ◽  
Principal Tool ◽  
The 19Th Century

In the 19th century, the microscope was the principal tool of biologists. The ordinary light microscope is designed to work on specimens that absorb light, but most unstained biological specimens do not absorb light appreciably and almost nothing is visible when such a specimen is viewed with the full aperture of the objective illuminated. However, they do show appreciable differences of refractive index, corresponding to variation in the concentration of solids, and the 19th century microscopists understood how to interpret the image when these were made visible by reducing the illuminating aperture and going slightly out of focus. If the objective is brought closer to the specimen (low focus), regions with high refractive index appear dark (positive image), and it became customary to use this setting, as in Fig. l (upper). As a result, the A bands of striated muscle fibres, with refractive index higher than the I bands, came to be known as the dark bands, although they appear bright with high focus.

scholarly journals The surface membranes of muscle fibres

1937 ◽  
Vol 122 (827) ◽  
pp. 140-154 ◽  
Keyword(s):  
Action Potential ◽  
Muscle Fibre ◽  
Algal Cell ◽  
Surface Membrane ◽  
Sartorius Muscle ◽  
Muscle Fibres ◽  
Plant Vacuole ◽  
Injured Part ◽  
A Cell ◽  
Aqueous Layer

The electrical properties of muscle are best explained in terms of the state of polarization of the surface of the muscle fibre. The uninjured surface of an isolated frog sartorius muscle is equipotential. Localized injury causes the injured part to be electrically negative to the uninjured surface. This indicates that normally the outside of the surface is positive to the inside. The same condition appears to exist in nerve fibres. Stimulation of muscle or nerve causes an impulse to move along the fibre. This impulse is a phase of depolarization which passes longitudinally along the surface of the fibre. The action potential which is a consequence of the depolarization has been much studied, but little is yet known of the nature and properties of the surface membrane at which the depolarization occurs. A consideration of the results of studies on the electrical behaviour of large single plant cells promises to throw some light on this problem (Osterhout 1929, 1931, 1934, 1935). The protoplasm of a cell of Valonia or Nitella forms a layer about 10 μ thick surrounding an aqueous vacuole. This protoplasm consists probably of an outer and inner layer of non-aqueous material and an intermediate aqueous layer. The evidence for this derives from (1) the shape of the action potential curve, and (2) the fact that a circuit consisting of cell sap—protoplasmic layer—cell sap has a considerable e. m. f., which would not be so if the protoplasm were homogeneous. It is the purpose of this paper to apply the method of the second criterion to muscle fibre, and to study this “asymmetry” potential. It is difficult to apply the same criteria to a muscle as to a large single algal cell for the following reasons. (1) A muscle comprises many fibres and the response of the inner fibres to a solute in he external medium is governed by the time of diffusion of the solute into the muscle. (2) An algal cell and a muscle fibre are histologically dissimilar. (3) It is impossible to extract the semi-liquid contents of a muscle fibre in the way that sap can be taken from a large plant vacuole. And an aqueous solution cannot be prepared of the same inorganic salt composition as muscle fibre because the phosphate content is too high and causes precipitation of Ca and Mg.

Grammatical Descriptions in Manchu Grammar Books from the Qing Dynasty

2019 ◽  
Vol 41 (1) ◽  
pp. 39-55
Author(s):  
Takashi Takekoshi
Keyword(s):  
19Th Century ◽  
Qing Dynasty ◽  
The Qing Dynasty ◽  
Chinese Scholars ◽  
High Degree ◽  
The 19Th Century

In this paper, we analyse features of the grammatical descriptions in Manchu grammar books from the Qing Dynasty. Manchu grammar books exemplify how Chinese scholars gave Chinese names to grammatical concepts in Manchu such as case, conjugation, and derivation which exist in agglutinating languages but not in isolating languages. A thorough examination reveals that Chinese scholarly understanding of Manchu grammar at the time had attained a high degree of sophistication. We conclude that the reason they did not apply modern grammatical concepts until the end of the 19th century was not a lack of ability but because the object of their grammatical descriptions was Chinese, a typical isolating language.

Immigrant Arab Women in Chile during the Renaissance (Nahda), 1910s-1920s

1970 ◽  
pp. 47-55
Author(s):  
Sarah Limorté
Keyword(s):  
20Th Century ◽  
19Th Century ◽  
Thematic Analysis ◽  
New World ◽  
Arab Women ◽  
Arab Woman ◽  
The Subject ◽  
The 19Th Century

Levantine immigration to Chile started during the last quarter of the 19th century. This immigration, almost exclusively male at the outset, changed at the beginning of the 20th century when women started following their fathers, brothers, and husbands to the New World. Defining the role and status of the Arab woman within her community in Chile has never before been tackled in a detailed study. This article attempts to broach the subject by looking at Arabic newspapers published in Chile between 1912 and the end of the 1920s. A thematic analysis of articles dealing with the question of women or written by women, appearing in publications such as Al-Murshid, Asch-Schabibat, Al-Watan, and Oriente, will be discussed.

THE IDEA OF «COMMUNITY» IN THE GOVERNMENT CONCEPTS OF GALICIA OF THE XIX – BEGINNING OF THE XX CENTURY

2019 ◽  
pp. 15-21
Author(s):  
Liubomyr Ilyn
Keyword(s):  
Nineteenth Century ◽  
19Th Century ◽  
Practical Significance ◽  
Distinctive Features ◽  
Legal Studies ◽  
Legal Principle ◽  
General Scientific ◽  
The Government ◽  
The Right ◽  
The 19Th Century

Purpose. The purpose of the article is to analyze and systematize the views of social and political thinkers of Galicia in the 19th - beginning of the 20th centuries. on the right and manner of organizing a nation-state as a cathedral. Method. The methodology includes a set of general scientific, special legal, special historical and philosophical methods of scientific knowledge, as well as the principles of objectivity, historicism, systematic and comprehensive. The problem-chronological approach made it possible to identify the main stages of the evolution of the content of the idea of catholicity in Galicia's legal thought of the 19th century. Results. It is established that the idea of catholicity, which was borrowed from church terminology, during the nineteenth century. acquired clear legal and philosophical features that turned it into an effective principle of achieving state unity and integrity. For the Ukrainian statesmen of the 19th century. the idea of catholicity became fundamental in view of the separation of Ukrainians between the Russian and Austro-Hungarian empires. The idea of unity of Ukrainians of Galicia and the Dnieper region, formulated for the first time by the members of the Russian Trinity, underwent a long evolution and received theoretical reflection in the work of Bachynsky's «Ukraine irredenta». It is established that catholicity should be understood as a legal principle, according to which decisions are made in dialogue, by consensus, and thus able to satisfy the absolute majority of citizens of the state. For Galician Ukrainians, the principle of unity in the nineteenth century. implemented through the prism of «state» and «international» approaches. Scientific novelty. The main stages of formation and development of the idea of catholicity in the views of social and political figures of Halychyna of the XIX – beginning of the XX centuries are highlighted in the work. and highlighting the distinctive features of «national statehood» that they promoted and understood as possible in the process of unification of Ukrainian lands into one state. Practical significance. The results of the study can be used in further historical and legal studies, preparation of special courses.

Book reviews

2017 ◽  
Vol 5 (2) ◽  
pp. 215-226
Author(s):  
Kurdish Studies
Keyword(s):  
19Th Century ◽  
Spatial Control ◽  
Cornell University ◽  
South Eastern ◽  
Turkish State ◽  
The 19Th Century

Andrea Fischer-Tahir and Sophie Wagenhofer (edsF), Disciplinary Spaces: Spatial Control, Forced Assimilation and Narratives of Progress since the 19th Century, Bielefeld: Transcript Verlag, 2017, 300 pp., (ISBN: 978-3-8376-3487-7).Ayşegül Aydın and Cem Emrence, Zones of Rebellion: Kurdish Insurgents and the Turkish State, Ithaca and London: Cornell University Press, 2015, 192 pp., (ISBN: 978-0-801-45354-0).Evgenia I. Vasil’eva, Yugo-Vostochniy Kurdistan v XVI-XIX vv. Istochnik po Istorii Kurdskikh Emiratov Ardelan i Baban. [South-Eastern Kurdistan in the XVI-XIXth cc. A Source for the Study of Kurdish Emirates of Ardalān and Bābān], St Petersburg: Nestor-Istoria, 2016. 176 pp., (ISBN 978-5-4469-0775-5).Karin Mlodoch, The Limits of Trauma Discourse: Women Anfal Survivors in Kurdistan-Iraq, Berlin: Klaus Schwarz Verlag, 2014, 541 pp., (ISBN: 978-3-87997-719-2). 

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