Or if, as often happens, an antitoxin is formed, which protects the whole body, this is largely built out of substances set free from the bodies of slain leucocytes. And the only thing that dims our vision to the wonder and beauty of this drama, is that it happens every day, and we term it prosaically "the process of repair," and expect it as a matter of course. Every wound-healing is worthy of an epic, if we could only look at it from the point of view of these citizens of our great cell-republic. And if we were to ask the question, "Upon what does their peculiar value to the body-politic depend?" we should find that it was largely the extent to which they retained their ancestral characteristics. They are born in the lymph-nodes, which are simply little islands of tissue of embryonic type, preserved in the body largely for the purpose of breeding this primitive type of cells. They are literally the Indian police, the scavengers, the Hibernians, as it were, of the entire body. They have the roving habits and fighting instincts of the savage. They cruise about continually through the waterways and marshes of the body, looking for trouble, and, like their Hibernian descendants, wherever they see a head they hit it. They are the incarnation of the fighting spirit of our ancestors, and if it were not for their retention of this characteristic in so high a degree, many classes of our fixed cells would not have been able to subside into such burgher like habits. Although even here, as we shall see, it is only a question of quickness of response, for while the first bands of the enemy may be held at bay by the leucocyte cavalry, and a light attack repelled by their skirmish-line, yet when it comes to the heavy fighting of a fever-invasion, it is the slow but substantial burgher-like fixed cells of the body which form the real infantry masses of the campaign. And I believe that upon the proportional relation between these primitive and civilized cells of our body-politic will depend many of the singular differences, not only in degree but also in kind, in the immunity possessed by various individuals. While some surgeons and anatomists will show a temperature from the merest scratch, and yet either never develop any serious infection or display very high resisting power in the later stages, others, again, will stand forty slight inoculations with absolute impunity, and yet, when once the leucocyte-barrier is broken down, will make apparently little resistance to a fatal systemic infection. And this, of course, is only one of a score of ways in which the leucocytes literally _pro patria moriuntur_. Our whole alimentary canal is continually patrolled by their squadrons, poured into it by the tonsils above and Peyer's patches below; if it were not for them we should probably be poisoned by the products of our own digestive processes.