Licence: Public Domain Mark
Credit: The liver / by Lionel S. Beale. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![DISEASED LIVERS AND MORBID GROWTHS. 2ig place to a blue tint. When this decidedly predominates the injection is complete. All superfluous tissue may then be removed, and the piece which is most thoroughly injected transferred to a small clean vessel that can be covered over to exclude dust, and glycerine con- taining one-third part of distilled water added so as to nearly immerse the specimen. After twelve hours' soaking, the greater part of the glycerine, now coloured and containing debris, may be poured away, and a little strong glycerine containing ten drops of acetic acid to the ounce added. This process is repeated day by day until the piece of tissue regains its blue colour. Sections may now be cut with a very sharp thin knife, and transferred to a little of the glycerine and acetic acid placed in a watch-glass. After having soaked for some time, they may be submitted to examination, and may be preserved in strong glycerine containing not more than five drops of strong acetic acid to the ounce. It will be observed that in this method of preparation the tissue is in contact with fluids miscible with water from first to last. Some degree of hardening is produced, and this may be increased by adding to the glycerine a little chromic acid and bichromate of potash solu- tion, as described in How to Work with the Microscope, but one cannot obtain thin sections of considerable area as by the hardening processes at present popular, These, however, produce such changes, and by their use so many structural points I can show clearly enough by other methods may be altogether lost, that I cannot accept some of the appearances seen in the specimens as representing the real structure of the part. In delicate nerve-tissues especially are these processes defective, and lead to a very erroneous idea of structural arrangement. The liquid filtering through the vascular or duct walls from the injecting fluid I have recommended preserves the tissue, and only requires the addition of a little more strong glycerine to the preparation to pre- serve it permanently. The process, at least in my own hands, worked admirably, and by its employment I have been enable to prepare very thin specimens of the most delicate textures, particularly of the ultimate distribution of nerve-fibres in the smaller vertebrata, which showed more than I was able to demonstrate by any other process. The pre- ])arations had also the great advantage of enabling me to demonstrate the disposition of nearly all the component textures in a single specimen. Great care is requisite for the successful preservation of specimens prepared as I have described, and which have to be preserved in strong glycerine, but the observer is well repaid for the extra trouble. As regards permanency, I have many specimens which have retained their characters for more than thirtyrfive years, but still they cannot be regarded as permanent as specimens which can be preserved in Canada balsam and such media.](https://iiif.wellcomecollection.org/image/b21930442_0289.jp2/full/800%2C/0/default.jpg)
