to the tendency of the fibrous tissue to shrink, that the skin over the tumor, and the nipple in the case of the mamma, become puckered and drawn in, and that the cut surface becomes concave.

Usual Seats.-The breast; but scirrhous cancer also occurs in the oesophagus, pylorus and, more rarely, in other situations. The general appearance of scirrhous cancer, the symptoms, diagnosis and treatment, are given under Diseases of the Breast, its favorite seat.

(b) The soft spheroidal-celled carcinomata, the medullary, encephaloid or acute cancers, are much more rapid in their growth than the preceding variety, and form soft and often large tumors, quickly terminating in ulceration and general dissemination through the body.

FIG. 15.

Structure. They consist (Fig. 15) of a scanty amount of stroma, which does not contract like that of scirrhus, and the cells, which are very prone to undergo fatty degeneration, are contained in large alveoli. They are very vascular, and as the scanty stroma affords but little support to the vessels, extensive hemorrhages into the substance of the growth are common. On section, they appear of a grayish-white or cream color, in places blotched with blood, while in the centre they may be almost diffluent, consequent upon their having undergone fatty degeneration. It is on account of this resemblance to brain-matter that they received their name from the older pathologists of encephaloid cancer, and to the fact that after they have involved the skin, they protrude in the form of a bleeding fungating mass, that they were further called fungus hæmatodes. Although, in accordance with general usage, the spheroidal-celled carcinomata are divided into hard and soft, it should be understood that no hard and fast line can be drawn between them, as the characters of the one often merge into those of the other, so that sometimes it may be difficult to decide whether an individual spheroidal-celled carcinoma should be classed as hard or soft.

Usual Seats.-The testis, liver, bladder, kidney, ovary and mamma. Secondary growths in internal organs consequent upon the dissemination of scirrhous cancer are often of the soft variety.

(c) The Colloid, Gelatiniform, or Alveolar Carcinoma.—These terms are applied to either of the above described varieties when they have undergone mucoid or colloid degeneration. It is believed that the degeneration generally begins in the cells which, as they become enlarged, so distend the alveoli that the latter can be seen by the naked eye. The colloid material is glistening, semi-translucent and jelly-like, or in places diffluent. In it some spheroidal cells are generally found. The favorite seats of these cancers are the stomach, intestine, omentum and ovary; but they occasionally occur in the breast.

2. EPITHELIAL CARCINOMATA always spring from the skin or mucous membrane, and constitute the second great division of the cancers. They are characterized by the resemblance of their cells to squamous or to columnar epithelium. The typical alveolar arrangement of the carcinomata is much less well marked than in the acinous form. They are divided into the squamouscelled and the columnar-celled epitheliomata.

(a) Squamous-celled Epitheliomata.-It was to this group of tumors that the term epithelioma was formerly restricted; but as all carcinomas are now believed to be epithelial growths, the term squamous-celled is prefixed to this variety to distinguish it from the columnar-celled and the spheroidal-celled carcinomata. Squamous-celled epitheliomata may spring either from the skin or from any mucous membrane covered by squamous epithelium, and are especially common where skin and mucous membrane meet, as the lips, anus, etc. They are most frequent in the old, seldom occurring under forty years of age, and are more common in men than in women. They are usually the result of continued irritation; thus in the tongue they may be due to the presence of a jagged tooth; in the lip, to the constant contact of a hot pipe stem; in the scrotum, to the retention of soot or coal-tar in the folds of the skin. They are also not uncommon in situations where the epithelium is in an abnormal condition, as in old scars, white patches on the tongue and inside of the cheek, chronic ulcers, warts and moles.

Structure.-Squamous-celled epitheliomata consist of columns of epithelium, which have grown into the connective or other underlying tissue, surrounded by an imperfectly fibrillated stroma, or by a small cell-infiltration. The epithelium is also proliferated outward, forming a warty excrescence or cauliflower-like growth. Breaking down rapidly ensues, and an epitheliomatous ulcer is the result. Among the cells forming the columns of invading epithelium are found in places small collections of cells of a crescentic shape, arranged concentrically around one or more central rounded cells. These collec

tions, spoken of as cell-nests, are probably due to the more rapid growth of the epithelium at certain spots, the shape and arrangement of the peripheral layers of cells being due to their compression between the rapidly-growing central cells and the surrounding tissues.

In the accompanying wood-cut (Fig. 16) the down-growth of the epithelial columns, a column in transverse section, and several cell-nests are seen.

Usual Seats.-Tongue, lower lip, cheeks, gums, vulva, scrotum, penis and anus.

Signs.-A squamous-celled epithelioma usually begins as a warty tubercle or fissure, which soon becomes an ulcer with everted, sinuous and indurated edges, and a hard, warty, and irregular base, while the tissues around become infiltrated with the growth and the nearest lymphatic glands enlarged. Unless the epithelioma is removed while the disease is still local,

recurrence usually takes place in the nearest lymphatic glands; and at times, like other forms of cancer, though less often, it may become disseminated through internal organs. When incompletely removed it will return in the scar. Death is usually the result of exhaustion consequent upon ulceration and hemorrhage. The signs, diagnosis, and treatment are further referred to under Diseases of Regions. (See Lip, Tongue, etc.)

(b) Columnar-celled epitheliomata, cylindrical carcinomata or adenoid cancers consist of cells derived from columnar or cylindrical epithelium, and are less common than the former variety. They begin as papillary outgrowths from the surface of mucous membranes covered with columnar epithelium, or from the interior of the mucous glands, and are most common in the rectum, though they may affect other parts of the intestine, the uterus, etc.

Structure. They consist of tubes lined with columnar epithelium, and bound together by a delicate connective tissue more or less infiltrated with small round cells. The epithelial cells retain more or less their shape, and are arranged at right angles to the walls of the alveoli, generally leaving a central space. In the more rapidly-growing tumors, however, the alveoli become completely filled with the cells. There are no cell-nests as in squamous epithelioma. Like other carcinomata they infiltrate the surrounding tissues, and may affect the lymphatic glands, and later become disseminated in internal organs, especially the liver. Death, however, usually occurs from obstruction of the bowel, hemorrhage from the ulcerating surface, or exhaustion, rather than from dissemination. Their appearance, symptoms, diagnosis and treatment are further described under Rectum.

THE TREATMENT OF CARCINOMA GENERALLY may be divided into the palliative and the radical. The palliative is resorted to when from some cause a cancer cannot be removed by operation, and consists briefly in soothing pain by opium, neutralizing the offensive smell when ulceration has occurred by antiseptics, and supporting the strength by nourishing diets and stimulants. The radical treatment aims at removing the cancer by operation, in the hope that it may not return or manifest itself in other parts. If removed early, there is a good chance of the squamous epithelioma not doing so, and in some forms of the columnar and acinous carcinoma the same fortunate result has occasionally occurred. As a rule, however, the issue is not so favorable, and after an immunity, varying in duration according to the variety, situation and size of the tumor, the length of time it has existed, and the implication or non-implication of the lymphatic glands, the disease returns in the scar, in the lymphatic glands, or in internal organs. But though the patient may not be cured by an operation, he may be greatly relieved by the removal of the local trouble, and die with less distress from implication of the internal organs by the disease. Should removal be determined on, it is best done by the knife; but in certain parts the scissors or écraseur may be more applicable. At times caustics may be employed. The various methods of removing carcinoma will be described more in detail under Diseases of Regions.

CYSTS.

A cyst is a cavity surrounded by a distinct wall, and containing in its interior fluid or pultaceous matter. It may be formed de novo, or by the distention of a pre-existing space or cavity, either by extravasation into it, or by an increase of its own secretion.

Classification.-Cysts may be divided into:

I. Cysts formed by distention of naturally existing cavities or spaces, subdivided into-A. Exudation cysts. B. Retention cysts. C. Extravasation cysts.

II. Cysts of independent origin, subdivided into-A. Simple

serous cysts. B. Blood cysts. C. Proliferous compound

cysts.

III. Congenital cysts.

IV. Parasitic cysts.

I. Cysts Formed by Distention of Naturally Existing Cavities or

Spaces.

A. EXUDATION CYSTS are formed by exudation or by excessive secretion into cavities which have no excretory duct. Under this head are included Bursæ, Ganglia, Cystic bronchoceles, Cysts in the broad ligament due to the dilatation of Graafian follicles, and Meningoceles. They will be further referred to under Diseases of Bursæ, Ganglia, etc.

B. RETENTION CYSTS are formed by the retention of the normal secretion and the consequent dilatation of the duct or acini of the affected gland. They are lined with epithelium; their walls become thickened by fibroid changes; and the natural secretion is altered by inspissation or by exudation from the cystwall. Three forms are described-1, atheromatous or sebaceous cysts, due to the dilatation of the sebaceous glands; 2, mucous cysts formed by the dilatation of mucous glands; and 3, cysts produced by the distention of large ducts, as the salivary, lacteal, hepatic, and renal ducts, and tubules of the testicle.

(1.) Atheromatous or sebaceous cysts occur mostly on the scalp or face, but may be met with on any part of the body, and are often multiple. They do not contain hair-follicles, papillæ, or other skin elements, thereby differing from the dermoid cysts which they otherwise resemble. Those on the scalp are sometimes hereditary. Signs.-They form smooth, lens-shaped, semifluctuating, movable swellings, often adherent to the skin. They may be distinguished from fatty tumors by not slipping from under the finger on pressing the edge of the swelling, and from an abscess by the absence of signs of inflammation. A small black punctum, the obstructed orifice of the sebaceous follicle, may moreover, in the case of a cyst, be discovered on its surface. Secondary Changes.-1. They may become inflamed and break down into an abscess. 2. One part may give way, and the sebaceous matter exude, become hardened, and be pushed up from below, and take the form of a horny growth. 3. Granulations may spring up from the interior of the cyst, and exude as