Volume 1
A textbook of pathology : systematic & practical.
- Hamilton, David James.
- Date:
- 1889-94
Licence: Public Domain Mark
Credit: A textbook of pathology : systematic & practical. 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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![EMBEDDING G1 Gelatine'and Freezing Fluid Embedding Mixture.—Where it is undesirable to apply spirit to a tissue, a mixture of 10 per cent gelatine in freezing fluid “A” should be substituted. This will be found to be unsuitable for brain, as the gelatine seems to swell when frozen, and destroys the delicate brain substance; celloidin is preferable. The tissue, such as an embryo or a portion of a stomach, is first stained in mass in carmine or some other staining reagent. It is next thoroughly freed from this by soaking in freezing fluid “A” with frequent changing, and is now ready to be transferred to the gelatine and freezing fluid “ A ” mixture in a stopper-bottle. In order to allow the gelatine mixture to thoroughly soak into every part, it is kept in a warm chamber at a temjDerature of 100° Fahr. for several days. The whole mass is subsequently allowed to cool in a beaker. When thoroughly gelatinised, the beaker is placed for an instant in hot water, and the gelatine, so loosened from its hold on the beaker, is removed. The embedded tissues are now cut out, still surrounded by a block of the medium, and are subsequently placed in freezing fluid “ B ” and retained permanently in this. If this freezing fluid is too strong, that is to say, if there is difficulty in freezing the tissues soaked in it, they should be transferred to “ A.” For embryos and such like delicate tissues, however, the “ B ” fluid will be found best. The sections are of course made in the freezing microtome. As before said, the above gelatine medium is unsuitable for em- bedding brain, but for many other purposes nothing could be more beautiful. It is superior to celloidin, jDaraffin, or wax in that the tissue can be transferred directly from water Avithout having been previously subjected to the action of spirit, ether, oil of cloves, or other reagent which might act deleteriously upon it. Embedding in Paraffin.—As a rule paraffin is inapplicable as an embedding medium for morbid tissues, unless Avhere the “ rocking microtome ” is employed. Its chief advantage is that ribbons of sec- tions may be obtained by its use, which are kept in proper serial order by adhesion of the one to the other. It is only for A^ery small bodies such as embryos that it can be recommended, and even these, if it is de- sired, can be cut in serial succession by the method detailed in Section 39. Stain the body first en masse in borax-carmine or some other pene- trating reagent. When this is completed, the superfluous staining fluid is Avashed out in Avater. The tissue is noAv transferred to abso- lute alcohol, and from this to oil of cloves. The oil of cloves should be allowed to act upon it until all the spirit has been remoA’'ed, the proper stage being knoAvn by its becoming transparent, or at any rate by its losing its natural opacity. A little paper boat is noAV prepared, and into it is ])oured some melted paraffin. The paraffin is alloAved to cool, and the body to be embedded is laid upon it. More melted paraffin is droi)ped from a pipette upon the body until it is thoroughly covered in. If it is desired to make the paraffin harder, colophony resin may](https://iiif.wellcomecollection.org/image/b24990607_0001_0089.jp2/full/800%2C/0/default.jpg)


