Cancer is a tumor generated by black bile, formed from the fumes of yellow bile matter or from matter that contained yellow bile and burned together with it, but not from pure sedimentary black bile. Cancer differs from scirrus in that with cancer there is pain, burning and some beating, and it quickly increases due to the abundance of matter and swells due to the boiling that occurs in the matter when it pours out to the affected organ. It is also distinguished by veins, similar to the legs of a cancer, which it releases around itself from the organ where it is located; they are not red, as happens with phlegmon, but rather blackish, brown or bluish. The difference between cancer and scirrhus is also that cancer in most cases occurs primarily, and hard scirrhus is more often formed by transition from a hot tumor. Cancer differs from true scirrus in that it is inherently sensitive, while scirrus is completely insensitive. In most cases, cancer forms in loose organs - which is why it occurs more often in women - as well as in organs rich in nerves.
For the first time after its occurrence, cancer remains in a latent state. When cancer appears, it is in most cases difficult to recognize, but then its signs become obvious. At first, when it first appears, it looks like a small, hard, round bean that is dark in color and a little hot. Sometimes cancer hurts a lot, and sometimes it doesn't bother you and only hurts a little.
In some cases the cancer leads to ulceration, since it comes from black bile, which is the fume of pure yellow bile alone, but in others it is stable and does not ulcerate; sometimes ulcerating cancer becomes non-ulcerating, and sometimes treating cancer with iron again leads to ulceration and creates thicker and harder edges. It seems that this tumor is called cancer due to one of two circumstances - either because it clings to an organ, as a crayfish clings to its prey, or because of its shape, in most cases round, its color and its protruding and surrounding its veins are like the legs of a crayfish.