An interesting study relates to the extension of the carcinomatous process in the skin; this occurs at first near, and then around, and even at a distance from the site of an operation, especially after removal of the breast. These nodules are at first small, and felt deep in or below the skin, and are not colored. They steadily increase in size, and when about that of a small pea, they become red and elevated a line or so. Later they may appear more numerous and even involve a large area, forming the so-called _cancer en cuirasse_, and may ulcerate. Sometimes single lesions of some size may appear here and there, even some distance from the site of the original tumor, and may not be colored. While these may represent lymphatic infarctions, it is often impossible to trace any direct connection with lymph ducts, and they more probably arise from capillary deposits of cancerous elements. I have frequently had these scattered cutaneous lesions excised, in cases under medical treatment, with a view of removing mechanically some of the foci from which the disease could be spread. The wounds have invariably healed promptly and perfectly, and no carcinomatous process has resulted.
The BLOOD IN CANCER has been studied mainly in reference to its solid constituents, and very little in regard to its plasma; whereas it is from the plasma that the blood corpuscles are formed, and this is the principal agent in the development and nutrition of tissues, normal and malignant. For it is to be remembered that the chyle is discharged directly into the venous blood current, and the venous radicles absorb much of the nutritive material directly from the abdominal organs. The plasma, therefore, carries with it constantly a varying quantity of partially assimilated material to be oxidized in the lungs, and slowly purified by the agency of the kidneys; the serum albumen and serum globulin are also active agents in the formation of tissue, malignant or other. There is great need of laboratory studies along these lines, and also on the alkalescence of the blood, which we found to have a marked diminution in cancer.
We know also comparatively little in regard to the origin and destruction of the cellular elements of the blood, and can only depend on the microscopic examination of their forms and appearances in health and in many conditions of disease. These have been abundantly studied morphologically, but mainly in the more severe forms and later stages of cancer, as detailed somewhat in my former lectures. Enough was there quoted to show the continued degeneracy of the blood after a cancerous growth had acquired some progress; there has also been observed some improvement for a while after the removal of a tumor, evidencing the deleterious effect of the hormone secreted by a cancerous mass.