Varieties of cancer depend mainly upon the relative proportions of the cells and binding tissue, and of a fluid—the cancer juice—also present in the growth. Thus hard cancer or scirrhus has the binding tissue in greatest abundance, and forms a very hard tumour; soft cancer, encephaloid or medullary cancer, contains more cells and is of a very soft con sistence, growing also with greater rapidity than the hard variety ; while epithelioma, or skin cancer, consists mainly of flat cells like those of the skin, or cells similar to those of glands, and occurs in the shape of an irregular ulcer.
position of the tumour may vary as already indicated. It may occur on the skin or on mucous membranes, like that of the tongue, lips, stomach, and other parts of the alimentary canal, in the bladder and womb, in glands, such as the salivary glands and breast, the glands of the intestinal tract, the liver, the testicle, the lungs, the eye, bone, lymphatic glands, nose, and many other parts. In fact it may occur almost anywhere. For even though it may originate only in epithelial structures, as already noted, it is easily transmitted to other parts, in which it could not begin, by the channels of the blood-vessels and lymphatics. In men a common seat of cancer is the lip, where it is of the epithelioma variety. In women the breast and womb are frequent situations, hard cancer being most frequently in tho breast. Internally the stomach, liver, and lungs are common situations.
Tile causes of cancer it is not easy definitely to state. Undoubtedly hereditary influence is great in many cases. Age has something to do with liability to the disease. The greater pro portion of cases in men occur between fifty-five and sixty years of age, and in women between forty-five and fifty-five. It is twice as common in women as in men ; and the liability seems to be greater in women who have borne children. These are of the nature of predisposing causes (see p. 28). Sometimes the occurrence of the growth seems to be determined in position by the presence of some long-continued irritation. Thus the irritation of a short juicy pipe, con stantly smoked, has determined the appearance on the lip, and the irritation of a ragged tooth on the tongue, while cancer of the breast in a woman hag followed at no distant time a blow on the breast. Frequently, of course, no such local cause can be suggested. It may be that with a constitutional tendency to the disease, it only required such an irritation to determine its occurrence.
The progress of the disease is slow or rapid according to the variety of the growth and its site, soft cancer being rapid in growth, epithe lioma very slow. In its course the tumour
continues growing for a certain time, and then it begins to break down, an irregular ulcer being formed from which a foetid discharge proceeds. In time, sooner or later as the disease spreads quickly or slowly, and according to the speed with which it extends to other organs, the health suffers, and a constitutional state arises to which the term "cancerous cachexia" has been applied. The countenance is peculiarly pale and sallow, and the suirerer wears a very anxious and careworn look. The general sur face of the body acquires a yellowish hue, the appetite is diminished, the strength gradually fails, and the pulse is weak. The patient com plains of lassitude and of inability for exertion. Emaciation sets in, at last death ensues from exhaustion, or the combined effects of discharge, debility, and pain. Life may, however, be shortened more speedily owing to the interfer ence of the tumour with the functions of some important organ, or to frequent attacks of bleeding from the ulcerating surface, caused by the disease opening into blood-vessels.
Symptoms of cancer it is impossible to dis cuss in detail. Those of cancer of the womb will be considered in the section on DISEASES OF WOMEN. sess regards internal cancer, its presence requires for detection a skilful and experienced physician. Concerning cancer of the lip and tongue it is only necessary to say that the presence of a ragged ulcer, with hard base, from which a foul discharge proceeds, and which refuses to heal, is suspicious, and ought to cause the sufferer to seek early and skilled advice.
Treatment.—No drug will cure cancer. The virtues of one medicine after another have been lauded in vain. Time and more experience have shown the worthlessness of them all. The only treatment for cancer is removal, if that is possible. Caustics have been used to burn out the mass, and are occasionally used still, but removal by the knife is the preferable operation. This a surgeon will not undertake unless with a prospect of being able to remove the whole growth. It must, therefore, be done early, before the disease has invaded lymphatic glands and other organs. When it is too late to operate, the only treatment is one to relieve the symptoms, to support the strength of the patient, and to alleviate pain. Each case must, however, be treated on its merits, and requires medical supervision.