Physiological histology, methods and theory / by Gustav Mann.

  • Gustav Mann
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Physiological histology, methods and theory / by Gustav Mann. Source: Wellcome Collection.

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    employed at all, or if a generic term is needed, then the word 1 plasm ’ serves better. If amongst histologists ‘ protoplasm ’ is a vague expression, then amongst chemists the word i proteid ’ is still more so. The question whether normally proteids do or do not contain salts seems to vex many, for they have not realized that so-called pure ash-free proteids are chemically inert and, in the true sense of the word, dead bodies. What puts life into them is the presence of electrolytes, either unorganized or organized. But this is discussed later in the chapter on colloids. How diverse the opinions of histologists have been in regard to the supposed nature and structure of living matter, and also in regard to the methods which are best suited for fixing purposes, will be set out in the following pages. Ever since the discovery of the cell, endeavours have been made to exclude the fictitious appearances produced by reagents. With this view, originally, substances were chosen which preserved the shape of the cell, but, as the internal cell-structures attracted more and more attention, the diverse appearapces which result from the use of different fixatives made control absolutely necessary= Two methods naturally suggested themselves, namely, to study the living cell before and while the reagents produced their effect, and also to investigate the behaviour of fixatives on isolated cell- derivatives such as egg-albumin and gelatin. Flemming1, whom we must regard as the pioneer in this research, has constantly laid stress on the point that we are not justified in regarding as normal all the structures to be seen in cells which have been treated with reagents. Knowing the fallacies accruing from ‘ fixing ’ cells, he, notwithstanding, published his osmo-chromo-acetic mixture, because he considered it the least liable to produce arte¬ facts, and the best for preserving the appearances seen in perfectly normal cells. As the result of his researches he arrived at the conception that ‘ protoplasm ’ has a threadlike or filar structure, which view in his later communications2 he combines with the trabecular theory, started by Frommann, Heitzmann, and Klein, and supported in recent times by the observations of van Beneden, M. Heidenhain, Solger, Kromayer, von Nathasius, Dogiel, Reinke and others. The original view of Flemming was, however, vigorously attacked by two botanists, namely, Berthold and Schwarz. Berthold3 in 1886 rediscovered, what has since been again discovered and extended by Ramsden4, that a 1 mechanical coagulum 9 can be produced by shaking white of egg with distilled water, and that this coagulum has the fibrillar appearance described by Flemming, while 1 Flemming : Zellsubstans, Kern und Zellthellung, Leipzig, 1882. 2 Flemming: 1 Zelle ’ in Ergebnisse der Anat, u. Entwickelungsgesch (Merkel and Bennet, 1893, and subsequent years). 3 Berthold : Studien u Protoplasmamechanik (1886). Berthold was not the original discoverer, see Bamsden. 1 Ramsden : see p. 50, On mechanical conglutination.
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