Then comes the last and strangest act of this weird tragedy. In the course of the resistless onward march of these rebel cell-columns some of their skirmishers push through the wall of a lymph-channel, or even, by some rare chance, a vein, and are swept away by the stream. Surely now the regular leucocyte cavalry have them at their mercy, and can cut them down at leisure. We little realize the fiendish resourcefulness of the cancer-cell. One such adrift in the body is like a ferret in a rabbit warren; no other cell can face it for an instant. It simply floats unmolested along the lymph-channels until its progress is arrested in some way, when it promptly settles down wherever it may happen to have landed, begins to multiply and push out columns in every direction, into and at the expense of the surrounding tissues, and behold, a new cancer, or "secondary nodule," is born (_metastasis_). In fact, it is a genuine "animal spore," or seed-cell, capable of taking root and reproducing its kind in any favorable soil; and, unfortunately, almost every inch of a cancer patient's body seems to be such. It is merely a question of where the spore-cells happen to drift and lodge. The lymph-nodes or "settling basins" of the drainage area of the primary cancer are the first to become infected, probably in an attempt to check the invaders; but the spores soon force their way past them toward the central citadels of the body, and, one after another, the great, vital organs--the liver, the lungs, the spleen, the brain--are riddled by the deadly columns and choked by decaying masses of new cells, until the functions of one of them are so seriously interfered with that death results. Obviously, this is a totally different process, not merely in degree, but in kind, from anything that takes place as a result of the invasion of the body by an infectious germ or parasite of any sort. There is a certain delusive similarity between the cancer process and an infection. But the more closely and carefully this similarity is examined the more superficial and unreal does it become. The invading germ may multiply chiefly at one point or focus, like cancer, and from this spread throughout the body and form new foci, and may even produce swarms of masses of cells resembling tumors, as, for instance, in tuberculosis and syphilis. But here the analogy ends.