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.
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![STAINING. into a paper boat which is immersed in chloroform, which sets the celloidin in a few hours without measurable alteration in bulk {Caldwell). When set somewhat firmly, the tissue with a convenient bed is cut out with a knife, and the block thrown into water for an hour (or if saturated with chloroform, into spirit and then into water). When all the alcohol is replaced by water, the block can be frozen and cut with a facility quite unattainable in spirit-set celloidin. There is no pleasanter material to cut than frozen celloidin. In some cases it is desirable to embed the tissue in celloidin, even before cutting into series of sections in paraffin. If this is desired, the chloroform-saturated block, or even the alcohol block, can be placed in melted paraffin.] STAINING. The investigation of the constitution of the central nervous system by means of sections only reached its full development when Gerlach showed us how to treat the preparation with staining agents which react differ- ently to the several tissue-elements. The stain which happened to be employed first was ammonia-carmine. To make the solution the best car- mine which can be bought (Carmine Naccarat) is mixed in a beaker with ammonia into a soft pap, to which so much distilled water is added as will yield a dark black-red fluid. The solution is filtered, and exposed to the air until the surplus ammonia has evaporated. The solution improves on keeping. The fluid can always be filtered back into the bottle after use, and may be employed for years. Alcohol preparations are very quickly coloured in this solution; a few minutes only being needed. Chromic preparations take a varying time, increasing with the time the preparation has been kept; it may vary from an hour to several days, and each case must be treated on its own merits. When it is desired to accomplish the staining quickly, the watch-glass containing the preparation should be placed on a wire net over a vessel of boiling water; three to five minutes usually suffices under these circumstances. For preparations in celloidin this method of heating is apt to prove too violent; it is safer to place them in an incubator. The time required for- staining depends upon the tempera- ture. For slight magnification the sections are cut thick and slightly stained; for use with high powers, deep staining is necessary. Beautifully differentiated carmine-staining can sometimes be effected by diluting the solution very greatly and leaving the sections in it for a long time, perhaps a couple of days. In carmine-staining the axis-cylinders, all cells non-nervous as well as nervous, the connective-tissue, and the epithelium should be bright red, the ground tissue pale pink, and the medullary-sheaths almost uncoloured; but many preparations take the colouring very slowly or fail altogether to present the proper sharp differentiation. In the latter case the fault lies either in the preparatory hardening or in the staining-agent. Good speci- mens of carmine have become so scarce, especially of late years, that many futile attempts are often made before a satisfactory solution is obtained.](https://iiif.wellcomecollection.org/image/b28716826_0042.jp2/full/800%2C/0/default.jpg)
