Histology; normal and morbid.
- Dunham, Edward K. (Edward Kellogg), 1860-1922
- Date:
- 1898
Licence: Public Domain Mark
Credit: Histology; normal and morbid. 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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![of an object under observation. It is rarely that sections hap])en to be made in such a direction that they reveal the complete struct- ure of an object. It is nearly always necessary to study the iijiijcar- ances presented by the section, and to infer what tlu; structure (»f the object must be in order to yield the appearances seen. This is sometimes a matter of considerable difficulty. If the ])lane of the section lie parallel with the long axes of the cells, the nuclei of the latter will appear as rod-like or long, oval bodies lying parallel to each other and distributed at regular intervals throughout the tissue. The outlines of the cells will be distinctly visible in some places, but in most of the section the boundaries of the deeper cells will be obscured by the bodies of the cells at the surface of the section, and the borders of the latter will be difficult of detection, because in many ])laces the knife has left oidy a portion of the cell with a very thin and trans})arent edge (Figs. 69 and 70). For the practical recognition of the tissue, when cut in this direction, Ave must, theref(H'e, in many cases, depend solely upon the shape and distribution of the nuclei and the color of the material between them after the section has been treated with certain stains [e. g., eosin). If the cells of the tissue have been cut perpendicular to their long axes, the section will contain true cross-sections of the indi- vidual fibres. These appear as round, oval, or, more usually, polygonal areas of various size, according to the part of the cell included in the section. If the cell has been cut near one of its ends, the cross-section will lie small ; if near the middle, it Mill be large, and will contain a cross-section of the nucleus, situated near its centre and appearing as a round dot (Fig. 71). It is in such sections that one may sometimes see the minute prickles or ridges, already referred to, projecting from the cell-bodies and joining with those of the contiguous cells to form delicate bridges across the narrow intercellular spaces. The only tissue with which this aspect of smooth muscular tissue is liable to be confounded is dense fibrous tissue, as seen in the cross-sections of tendons or ligaments (Fig. G<)). There we also see polygonal areas of various sizes, separated for the most part by only a thin layer of cement. But these areas never contain nuclei, because they are composed, not of cell-bodies, but of intercellular substance. The nuclei of the flattened connective-tissue cells may be seen here and there apparently lying within the cement, the body of the cell being](https://iiif.wellcomecollection.org/image/b21223841_0081.jp2/full/800%2C/0/default.jpg)
