Microscopical morphology of the animal body in health and disease / by C. Heitzmann. With 380 original engravings.
- Carl Heitzmann
- Date:
- 1883
Licence: Public Domain Mark
Credit: Microscopical morphology of the animal body in health and disease / by C. Heitzmann. With 380 original engravings. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![Frt'sli sju'cinHMis, if in the sh;i|M' of delicate nieniliraiies, are spread over the glass slide, while, if in the shape of masses not transparent, they are ent with the nizor in a frozen condition. The free/inu- mixture may l)e snow oi- hroken ice with salt in one compartment of a metal 1k)X, while the other compartment holds the specinieu, fixi'd, if necessary, by mucilage of gum arable. Numerous freezing microtomes have been invented; in some, rliigolene or ether-spi-ay is i)roduced, by means of which a fresh specimen may in a few minutes be frozen to such a consistence that it can be cut with a razor. Specimens so obtained are useful for temporary examinations or for staining, especially witli chloride of gold. Freshly cut specimens may be preserved by tlie addition of a very ddute solution of l)icliromate of po- tassa, which is aUowed to flow under the covering-glass, and is drained off by strips of faltering ])aper held against the edge of the cover. Preservation of Tissues. The best method of preservation and hardening of normal and morbid specimens is to divide a large mass of the tissue by incisions into small pieces, of one or two inches diameter, and to place these pieces in a wine-yellow solu- tion (one-half per cent.) of chromic acid. The chromic acid is kept ready in strong solution, of which a small quantity is added to the water holding the specimen in a glass jar. It is important that the specimens be placed in a large quantity of liquid, its hulk exceeding that of the specimen at least five or six times. These precautions are necessary, as the hardening action of chromic acid does not penetrate very deeply. In t)ne oi- two days, the liquid having become cloudy, the chromic acid solution must be renewed, and such renewal is to be repeated every few days until the solution remains clear. Specimens of bone or teeth are treated in the same manner, and the extraction of the lime-salts may be hastened by a very cautious addition of dilute muriatic acid every foui'th or fifth, day. If the chromic acid be apphed in this way, it hardens the tissues in a few days or weeks, with no other change than a slight shrinkage, and renders them fit for cutting with the razor. After the specimens have been hardened, we still may keep them in very dilute solutions of chromic acid, to which we add small quantities of alcohol in order to prevent the growi:h of mildew, the most unpleasant enemy of a laboratory for microscopic research. A dark wine-yellow solution of bichromate of potassa is also suitable for the preservation of specimens, though in such a](https://iiif.wellcomecollection.org/image/b21219163_0031.jp2/full/800%2C/0/default.jpg)
