next discovered that pigeons cannot be made to take tuberculosis, for, here again, phagocytes seized the tubercle bacilli as fast as they entered the body and devoured them before any harm was done.

The work which the phagocyte does for the body is so valuable that we easily talk about this free-swimming, single cell as if it were a many-celled warrior with a mind of its own. In point of fact, however, and even though they do behave like friend and foe, there is no real enmity between the phagocyte and the microbe.

These small protectors of the body move from place to place in independent fashion. They spend most of their time in the blood; and in it they not only travel with the current but they also ignore that current entirely, and, like the salmon, swim up stream as well as down stream, as occasion may seem to require. At a moment's notice, also, they leave the blood and pass through any bodily tissue without the slightest difficulty.

Through Professor Metchnikoff's experiments and others since then, facts have been learned which help human beings. If our phagocytes are strong enough to destroy disease microbes for us, we shall be saved from certain serious diseases. If, on the contrary, our phagocytes are feeble, or if microbes enter our body in such swarms that there are not phagocytes enough to fight them successfully, the enemy will be victorious, the phagocyte will be defeated, and we shall be the victims.

of any special epidemic that is traveling the rounds. Put two men into a town where cholera is working havoc; let one have more vigorous phagocytes than the other, and he will be the one more likely to escape with his life. Let measles or pink eye, whooping cough or influenza, break out in school, and those children with the most numerous and active phagocytes will suffer the

INFLUENZA MICROBES UNCONQUERED BY PHAGOCYTES

On the left, as they are found in the sputum of some colds; on the right, as they are raised in the laboratory

least. Let tubercle bacilli be thick in the dust we breathe, and those of us who own the best bodyguard in the line of well-developed phagocytes will be least likely to take the disease and suffer from tuberculosis afterwards.

The same law holds true even for less serious illness. When some one says, "I am so sensitive, I catch cold

at the least exposure," it is quite as if he said, “ My phagocytes are wonderfully weak and inefficient, they are vanquished by all the microbes of influenza that enter my body." Another person says, "I never seem to take cold," and it is as if he said, "My phagocytes are such valiant warriors that they destroy every intruding microbe."

Yet the phagocyte is not merely an athletic policeman, a valiant soldier; he is also a scavenger and a street cleaner. With all his occupation he is never idle. Here and there through the body he hurries, always trying to remove waste matter and intruding microbes.

You cut your hand, or you run a sliver into your finger, and from every side phagocytes hasten to clear away the rubbish and to attack the microbes. If they can kill these mischief-makers as fast as they drift in, the wound will heal fast; if, instead, the phagocyte is too weak to slay the enemy, there will be a painful sore, slow to heal.

Hospitals are full of patients who prove this difference in their own bodies. One man has a wound that heals at once, and he goes home happy; another man stays in the hospital for weeks waiting for his wound. to heal. The difference in recovery rests with the phagocytes of the two men. "Matter," or "pus," from a wound is the host of microbes and phagocytes that have been slain in the struggle. They are being washed away by fluids from the wound.

CHAPTER XIV

PHAGOCYTE AND ALCOHOL (CONTINUED)

The warfare within our bodies is a silent one. We hear no sign of any conflict; nevertheless, throughout our lives the strife goes on ceaselessly, and it makes all the difference between life and death to us whether or not our standing army of phagocytes is in good fighting trim.

In view of this fact our daily command to ourselves should be: Protect the phagocytes from harm. Every law of health is, indeed, so truly a law for their protection that he who follows health laws most strictly will at the same time be doing the most for his bodyguard. It is necessary, however, that we should know even more than this. Multitudes of cases prove the need.

In Glasgow, in 1848, a little more knowledge might have saved hundreds of lives. As shown in Town and City, Dr. Adams kept a keen eye on the death rate of his cholera patients, and he discovered that those who went without alcohol had a vastly better chance to recover than those who used it. Or, to put the facts more exactly, when those who used alcohol caught the disease

ninety-nine out of every hundred died; whereas, when those who did not use alcohol had the cholera, only nineteen out of each hundred died.

Knowing what we do about the effect of alcohol on the living cell, and knowing also about the discoveries which Professor Metchnikoff made in connection with cholera microbes and phagocytes, we understand at once the condition of affairs in Glasgow. Those men and women who did not use alcohol owned phagocytes that were vigorous enough to conquer the attacking cholera microbes; those other men and women who used alcohol had weakened their phagocytes to such an extent that when invading enemies came they were not strong enough to slay them.

Dr. Delearde had two cases which illustrate precisely this point.

A man and a boy were bitten on the same day by the same mad dog. The boy, thirteen years old, was bitten on the head and face, which are the very worst places. for such wounds. The man was bitten on the hand alone -a much less serious matter. Both victims were taken to Dr. Delearde, and he gave each his most careful treatment; but the man, who should have recovered, died of hydrophobia, and the boy, who might have been expected to die, recovered. The only difference in the two cases seemed to be that the man used alcohol and that the boy did not use it.