Volume 1

Handbook for the physiological laboratory / by E.E. Klein, J. Burdon-Sanderson, M. Foster, and T.L. Brunton ; edited by J. Burdon-Sanderson.

  • Klein, E. (Edward) 1844-1925.
Date:
1873
Catalogue details

Licence: Public Domain Mark

Credit: Handbook for the physiological laboratory / by E.E. Klein, J. Burdon-Sanderson, M. Foster, and T.L. Brunton ; edited by J. Burdon-Sanderson. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    be temporarily mounted in glycerin, but cannot be preserved for a length of time in that liquid. All sections which are intended to be permanent, exceptmg those of tissues prepared by the gold or silver methods, must be mounted in Canada balsam or Dammar; the last being preferable, as more easy to manipulate. It is prepared as follows :— Preparation of Dammar Varnish.—Half an ounce of gum ])ammar in powder, is dissolved in an ounce and a half or two ounces of turpentine, and half an ounce of gum mastic in two ounces of chloroform. The two solutions are then separately filtered and mixed. This varnish so obtained is clear, and if exposed in a thin layer on a plate of glass solidifies rapidly. The sections which are to be mounted must be placed, for a quarter of an hour or more, in a capsule containing absolute alcohol, which should be provided with a cover. Each section must be raised with the aid of a gern)an-silver or copper lifter (the blade of which is then placed on blotting-paper, to remove the adhering alcohol), and transferred to a watch-glass containing oil of cloves. By this means it becomes, in a few seconds, quite transparent. If it is coloured, the colour becomes more intense ; if it is unstained, it becomes almost invisible. From the oil of cloves it is transferred by the same means to a drop of Dammar varnish, previously placed in the centre of an object-glass.* If excessively delicate and thin sections are to be mounted, such, e.g., as sections of the retina, or of any thin membrane, it is not possible, without risk, to transfer them from one liquid to another. In this case it is, therefore, necessary to swim the section directly from the knife on to the object-glass, in which ])osition they must be treated with the several liquids to be em- ployed; and each liquid must be allowed to fall on to the section, and, after producing its effect, removed by inclining the glass, care being taken not to allow the object to float away at the same time. All delicate sections must be protected by the interposition, be- tween the object and cover-glass, of a square of silver paper, with a window cut in it somewhat smaller than the latter. Methods of Preserving Preparations permanently.—Pre- parations which are to be preserved must be mounted permanently. Those which are in liquids, such as glycerin, acetate of potash, bichromate of potash, &c., must be surrounded with cement, in order to fix the cover-glass. For those which are in glycerin * The lifter or spoon may be made by flattening the end of a copper or german-sil ver wire, and bending it at right angles. It is desirable to place the object-glass on a white ground if the object is stained, or on a black ground if it is unstained, in order that the folds, if present, may be seen and removed. If several sections are to be placed under one cover-glass, each section may be pressed gently down on the surface of the gla.ss before covering ; the sections then adhere to the glass sufficiently to keep ia their places.