The anatomy of the central nervous organs in health and in disease / by Heinrich Obersteiner ; translated, with annotations and additions, from the third German edition, with all the alterations and corrections prepared by the author for the forthcoming fourth German edition by Alex Hill.
- Heinrich Obersteiner
- Date:
- 1900
Licence: In copyright
Credit: The anatomy of the central nervous organs in health and in disease / by Heinrich Obersteiner ; translated, with annotations and additions, from the third German edition, with all the alterations and corrections prepared by the author for the forthcoming fourth German edition by Alex Hill. Source: Wellcome Collection.
52/608 page 24
![Staining fluid: 2 per cent, acetic acid, 100 parts; acid rubin, 0'25 part; saturated watery solution of picric acid, 100 parts. Three parts of this mixture are added to 100 parts 96 per cent, alcohol, the sections are placed in it for half an hour or more, and are then twice washed in alcohol. Carbol-xylol, varnish. For the purpose of distinguishing the gelatiniferous connective-tissue from the neurogleia in sections treated by his own modification of Ivultschitzky’s method (p. 22), J. Schaffer recommends that they should be kept for a long time (days or weeks) in a very thin solution of eosin (about 2 drops of a 1 per cent, watery solution to 10 cubic centimeters of water). By this process the fibres of the neurogleia show white, the connective-tissue remaining brown. This differentiation succeeds as a rule only in the peripheral parts of the section. METHODS OF IMPREGNATING WITH METALS. Of the principal methods of colouring by impregnation only a few of the chief need be mentioned. 1. Exner’s Perosmic Acid Method.—Quite small pieces of nerve-tissue (at the outside not more than a centimeter thick) are placed in a sufficient quantity of 1 per cent, perosmic acid solution. The solution is changed at least once every two days, oftener when the pieces are large. In five to ten days the pieces are darkly coloured, but they may remain for a longer time in the solution. [Good results are often obtained in twelve to twenty-four hours ; the preparations should, while in the osmic acid, be kept in the dark.] The preparation is then washed [a quarter to half an hour in running water is by no means too long to remove all traces of dissolved osmic acid and prevent subsequent precipitation on the addition of alcohol], placed for a few seconds in alcohol, embedded and cut. The sections, which must be very thin, are cleared in glycerin, lifted with adhering glycerin on to a slide, on which a drop of strong ammonia-water has previously been placed, and covered with a cover-glass after exposure to the air for a few minutes. Even the finest medullated fibres are stained dark grey. The fault of this excellent method is that the preparations quickly degenerate and aie often useless in a few days. [Permanent preparations, although with some faults incidental to the solution of the fat, are obtained by mounting the section, after the usual dehydration, in Canada balsam.] The method can only be applied to very small pieces of tissue. An excellent method of staining medullated fibres in osmic acid was introduced by Azoulay. The tissue is hardened in Muller’s fluid, then in alcohol, and embedded in celloidin in the usual way. The sections arc washed and placed for five minutes to a quarter of an hour in a weak watery solution of osmic acid (1 to 500 or 1000), washed quickly in water and transferred to a 5 per cent, to 10 per cent, solution of tannic acid. In this they remain at a temperature of 50° C. until they have acquired the requisite depth of colour (which they do, on an average, in five minutes),](https://iiif.wellcomecollection.org/image/b28716826_0052.jp2/full/800%2C/0/default.jpg)
