The essentials of histology : descriptive and practical for the use of students / by E.A. Schäfer.
- Edward Albert Sharpey-Schäfer
- Date:
- 1894
Licence: Public Domain Mark
Credit: The essentials of histology : descriptive and practical for the use of students / by E.A. Schäfer. Source: Wellcome Collection.
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![the formic acid mixture for 24 hours, and into pure formic acid for 24 hours more. After removal from tlie gold, and whilst in the acid, the tissue must be kept in the dark. y. Ranvier's method.—Immerse in lemon-juice for 5 to 10 minutes, then wash with water and place in 1 per cent, gold chloride solution for 20 minutes. Then treat either as in Cohnheim's or as in Lowit's method. 16. Staining with nitrate of silver.—Wash the fresh tissue with distilled water ; immerse in ^ to 1 per cent, nitrate of silver solution for 5 to 10 minutes ; rinse with distilled water and expose to bright sunlight either in water, alcohol, or glycerine. This method is used to exhibit endothelium and generally to stain intercellular substance. 17. Golgih nitrate of silver methods.—These are chiefly employed for investigating tlie relations of cells and fibres in the central nervous system. Two methods are mostly used, as follows :— a. Very small pieces of the tissue which has been hardened for some weeks in bichromate solution or Midler's fluid are placed for half an hour in the dark in 0'75 per cent, nitrate of silver solution, and are then transferred for 24 hours or more to a fresh quantity of the same solution (to which a drop or two of formic acid may be added). They may then be hardened with 50 per cent, alcohol, and sections, which need not be thin, are cut either from celloidin with a microtome or with the free hand. The sections are mounted in Canada balsam, which is allowed to dry on the slide : they must not be covered with a cover-glass, but the balsam must remain exposed to the air. Instead of being slowly hardened in bichromate, the tissue is placed at once in very small pieces in a mixture of bichromate and osmic (3 parts of Miiller's fluid to 1 of osmic acid). In this it remains from 1 to 2 days, after which the pieces are treated with silver citrate as in the other case. This method is not only more rapid than the other, but is more sure in its results. 18. EhrlicKs methyl-hlue method.—This method is one of great value for exhibiting nerve-terminations, and in some cases the relations of nerve-cells and fibres in the central nervous system. For its application the tissue must be living : it is therefore best applied by injecting a solution of methyl-blue (1 part to 100 of saline solution) into the blood-vascular or into the lymphatic system, but good results can also sometimes be obtained by immersing small pieces of freshly-excised living tissue in a less concentrated solution (0'2 per cent.) In either case the tissue must be spread out in a thin layer freely exposed to the air ; the blue colour then appears in the nerve-cells and axis- cylinders, even to their finest ramifications. To fix the stain the tissue is treated for some hours with saturated solution of picrate of ammonia, after which the preparation can be mounted in glycerine. Mounting Solutions :—1. Saline solution.—A. 0-6 per cent, solution of common salt is used in ])lace of serum for mounting fresh tissues for imme- diate examination. 2. Glycerine, either pure or diluted with water. The cover-glass may be fixed by gold size. 3. Canada balsatn, from which the volatile oils have been driven ofi' by heat, dissolved in xylol.](https://iiif.wellcomecollection.org/image/b20400585_0318.jp2/full/800%2C/0/default.jpg)
