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THEORY AND PRACTICE OF MEDICIXE.
contains a quantity of these cells, as well as nuclei, and free gra- nules. The sliwna is generally firm and fibrous, the fibres being either delicate or coarse ; but if it has developed rapidly, it presents an embryonic structure. The vessels are solely distributed in this stroma, and its fibrous bundles intersect in all directions, forming a communicating network, within the alveoli of which the cells are grouped. Lymphatics have been found accompanying the blood- vessels, and they communicate with the alveoli.
In scirrhus the cells, though they may be abundant at first, speed-
Primary cancer of Rectum. {Crci^Mon). shapc from mutual pressure.
centric globes or Jicsts, or so-called epilhelial pearls, which increase from within, so that the outer layers become hardened and flattened. Ultimately the entire groups of cells may become dry, firm, and brownish-yellow. A variable amount of stroma is present.
Cancerous growths are very liable to fai/y degeneration, especially the softer forms, and as a result the cells become more granular, and softening takes place; or parts of the growth may assume a caseous appearance, Calcificatmi is very uncommon. Melanosis and colloid are generally regarded as forms of cancer which have undergone these peculiar degenerative processes. All cancerous growths tend to ulcerate, the ulcers having no disposition to heal, but being on the other hand inclined to spread.
Organs and tissues afFected. Scirrhus is usually observed in the mammary gland, uterus, stomach, rectum, or skin. Encepha- loid affects chiefly the bones, testicles, eyes, and internal or gans, especially the lungs, liver, kidneys, brain, and spleen.
Fin. 13.
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ily disaf)pear, and the fibrous stroma is greatly in excess, especially towards the centre of the growth, where finally no cells at all can be discovered. In encephaloid, on the other hand, the cells are greatly in ex- cess, developing rapidly and as speedily degenerating, becoming- granular, and their nuclei being set free. There is but little stroma, which is soft, delicate, and very vascular. Colloid is in great part structureless, but some cells are present, which are large and spherical, often having a lamellar outline, and containing some of the colloid material. Epithelioma presents generally a large number of cells, which, with few exceptions, are exceedingly like those of scjuamous epithelium, but are subject to great alterations in
They tend to form peculiar co7i-
