Essays and observations on natural history, anatomy, physiology, psychology, and geology / by John Hunter, being his posthumous papers on those subjects, arranged and revised, with notes ; to which are added the introductory lectures on the Hunterian collection of fossil remains delivered in the theatre of the Royal College of Surgeons of England, March 8th, 10th and 12th, 1855 / by Richard Owen.
- John Hunter
- Date:
- 1861
Licence: Public Domain Mark
Credit: Essays and observations on natural history, anatomy, physiology, psychology, and geology / by John Hunter, being his posthumous papers on those subjects, arranged and revised, with notes ; to which are added the introductory lectures on the Hunterian collection of fossil remains delivered in the theatre of the Royal College of Surgeons of England, March 8th, 10th and 12th, 1855 / by Richard Owen. Source: Wellcome Collection.
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![cuticle from the cutis; but putrefaction is the best; for boiling water does not do it so regularly over the whole. Of the transparent Preparation of Bones.-—Bones in many animals are a mixture of earth and animal matter; as the earth is in the form of a powder or calx it is opake. To render such a bone transparent, it is necessary that this earth should be extracted and nothing left but the animal substance. To do this, the bone should be steeped in an acid, with which the earth unites and dissolves. The acid should be so diluted as to have but little effect upon the animal part; however, the weakest acids will, in some degree, affect it, which is of some advantage, as it renders the preparation still more transparent. The acid should be diluted so as only to feel a little sharp to the tongue. Perhaps common vinegar is as strong as it shotdd be. Water is commonly the fluid the acid is diluted with, and is as proper as any- thing when the preparation is simply a bone that is to be put into it: but it is sometimes necessary that soft parts are also connected with the bone to complete the preparation. In such cases, to preserve the soft parts from putrefaction, it is proper to dilute the acid with spirit, which preserves the soft parts while the acid is extracting the earth. If the quantity of liquid is too small to allow of a sufficient quantity of acid to dissolve all the earth in the bone, then more acid may be added to the same liquid when that which was first put is fully satu- rated, which will be in a day or two. Vitriolic acid should never be used, as it does not dissolve the earth of bones, but unites with it in the form of selenites [sulphate of lime]. The marine [nitric] acid should be as pure as possible, or free from any vitriolic acid. Of Wet Preparations.—Preparations should never be allowed to have any considerable tendency to putrefaction before they are put into spirits, because the part or piece putrefied does not coagulate so soon, nor so firmly, as the fresh; therefore you will have the spirits made or kept much longer foul from the oozing of the uncoagulable juices ; but, where it is unavoidable, the spirit should be strong in proportion, espe- cially if the mass be large. If the preparation is made in the summer, and is pretty large, it will be hardly possible to prevent putrefaction before it is properly steeped; therefore it will require, at first, either more spirit than common, or stronger. Of the Colour of Wet Preparations.—As all parts of an animal are nearly of the same colour when deprived of their blood (excepting the skin and some glands, as the liver, which take much of their colour from the juice which they secrete), great care should be taken not to deprive such parts of their blood, which owe much of their distinction](https://iiif.wellcomecollection.org/image/b21182656_0421.jp2/full/800%2C/0/default.jpg)
