The microtomist's vade-mecum : a handbook of the methods of microscopic anatomy.

  • Arthur Bolles Lee
Date:
1890
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Licence: Public Domain Mark

Credit: The microtomist's vade-mecum : a handbook of the methods of microscopic anatomy. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    branes by preference) are brought fresh into a 4 per cent, solution of methylen blue in physiological salt solution. After a few minutes therein they are brought into saturated solution of picrate of ammoniaj soaked therein for half an hour or more, then washed in fresh picrate of ammonia solution, and examined in dilute glycerin. If it be wished only to demonstrate the outlines of endothelium cells, the bath in the stain should be a short one, not longer than ten minutes in general. Whilst if it be desired to obtain an impregnation of ground-sub- stance of tissue so as to have a negative image of juice-canals or other spaces, the staining should be prolonged to fifteen or thirty minutes, and it is advisable to remove the endothelial covering of the objects operated on before putting them into the stain. If it be desired to preserve the preparations permanently, they had better be mounted in glycerin saturated with picrate of ammonia. The effect is practically identical (except as regards the colour) with that of a negative impregnation with silver nitrate. If the process bears out all that is claimed for it, it will certainly be valuable ; for there are many objects to which metallic impregnation cannot be readily applied. Marine animals furnish many cases in point. 767. Venice Turpentine for Mounting (Vosselee, Zeit. f. wiss. MiJc., vi, 3, 1889, p. 292, et seq.).—Vosseler strongly recommends this medium as having considerable advantages over Canada balsam or damar. Commercial Venice turpentine is mixed in a. tall cylinder glass with an equal volume of 96 per cent, alcohol, allowed to stand in a warm place for three or four weeks, and decanted. It is stated that preparations may be mounted in this medium without previous clearing with essential oils or the like. The index of refraction being lower than that of the above-named balsams delicate details are more distinctly brought out. Stains keep well in the medium, and Vosseler states that he possesses preparations made fifteen years ago that are perfectly well preserved. 768. Gelatin-Soap Imbedding Mass (Godfkin, Journ. de Bot., 1889, 5, p. 87 ; abstract in Zeit.f. wiss. Mile, vi, 3, 1889, p. 317). Very compli- cated and, as far as I can judge from the report, rather of the nature of an emulsion than of a homogeneous mass. 769. Platino-Aceto-Osmie Mixture (Heemann, Arch. f. mile. Anat., xxxiv, ]889, p. 58).—The author obtained excellent results by substituting 1 per cent, platinum chloride for the chromic acid in Flemming's strong formula, the other ingredients either remaining as before, or the osmium being diminished one half. Thus—1 per cent, platinum chloride 15 parts, glacial acetic acid 1 part, and 2 per cent, osmic acid either 4 parts or only 2 parts. Hermann found that protoplasmic structures are thus better pre- served than with the chromic mixture, which appears to me very likely. 770. Iodine Hsematoxylin (Sanfelice, Journ. de Microgr., xiii, 1889, p. 335; Jown. Boy. Mio. Soc, 1889, p. 837).—Dissolve 0'70 g. htema- toxylin in 20 g. absolute alcohol, and 0-20 g. alum in 60 c. c. distilled water. Add the first solution, drop by drop, to the second. Expose- the mixture to 25