A manual of pathological histology / by V. Cornil and L. Ranvier ; translated, with notes and additions, by E.O. Shakespeare and J. Henry C. Simes.
- Victor André Cornil
- Date:
- 1880
Licence: Public Domain Mark
Credit: A manual of pathological histology / by V. Cornil and L. Ranvier ; translated, with notes and additions, by E.O. Shakespeare and J. Henry C. Simes. Source: Wellcome Collection.
771/808 page 751
![parts of chromic acid to 1000 parts of water, commencing with the weaker and ending with a stronger proportion. This reagent makes the tissues too brittle if they are left too long exposed to its action. It is particu- larly valuable for the nervous system and extremely delicate tissues. Picric Acid.—It should be used in saturated solutions. The crystals are not very soluble. Hence solutions should be made with warm water, or if made with cold water the sediment should be well stirred at intervals during two or three days. With this fluid the tissues are better placed at the bottom of the vessel. Time Required for Hardening.—Most of the tissues are hardened in a few days when placed in alcohol or in picric acid. The latter fre- quently makes the tissue sufficiently firm for rough sections Avithin twenty hours. Nerve tissue, especially that of the centres, the brain, and spinal marrow, requires much longer exposure to the action of the reagent. The brain or spinal cord must be immersed in chromic acid, Muller's fluid, or bichromate of ammonia five or six weeks before it is sufficiently firm and tough. Treatment of Tissues after Hardening.—When the specimen has become sufficiently firm, it should be removed from the hardening agent if chromic acid, picric acid, bichromate of ammonia, or Muller's has been used, should be thoroughly soaked in water until the tissue ceases to tinge the water, and finally placed in alcohol of 85 per cent, for indefi- nite keeping. Decalcifying Agents.—Both saturated picric acid and chromic acid, in the strength of 2—5 parts to 1000, possess the property of dissolving the calcareous salts in bones or other tissues. Where the piece to be acted upon is very small and the fluid is in large amount, the acid should be often renewed. The portion of tissue to be softened should not exceed a quarter of a cubic inch, and the fluid should not be less than five or six fluid ounces. These agents harden the elements at the same time that they dissolve the lime salts.]](https://iiif.wellcomecollection.org/image/b2041772x_0771.jp2/full/800%2C/0/default.jpg)
