Page:Popular Science Monthly Volume 40.djvu/843

Rh breaks down the great mass of waste into harmless products, there should be this comparatively slight residue left over—reminding one of a lawless fraction of people in an orderly state—which can not be got rid of on the same easy terms. As we have seen, we have about five pounds three ounces of daily waste that is safely got rid of as urea, carbonic acid, and water, by means of kidneys, skin, and lungs; but accompanying this safe discharge we have a few grains of poison—a sort of surplus of evil—which in some way or other seems to resist the oxidation to which all the other mass of waste has been subject. What, then, is this poison? How far is it the same, how far does it differ from the normal poisons of the tissues, which, as we see, in a few minutes destroy life when oxygen is withheld? Where and how is it formed? Are we to look upon it as a putrefactive poison formed at the surface of the lungs and the skin, when waste of some kind is escaping through these channels? Dr. Klein tells us (pages 61 and 241) that septic bacteria (the authors of putrefactive change) are to be found in those parts of the body into which air penetrates, as the mouth, the air-passages, the whole alimentary tract; but it seems difficult not to believe, whatever changes take place as these poisons reach the air, that they must at all events have existed as chemical poisons when still in the tissues. Are we, then, to look upon these poisons as derived from putrefactive decompositions taking place in certain parts of the body; or as poisons derived from the tissues; or as in turn possessing both characters? At present, both within and without the body, their nature is surrounded with mystery, and many are the interesting questions that remain to be solved about them. When they have passed outside the body, are they the food of any of the bacteria which are found so plentifully in foul air? If so, are the ordinary bacteria (excluding the case of certain bacteria producing disease) our friends or our enemies; do they render the poison itself harmless; or do they themselves produce an excretion which is of a poisonous character; or should they be looked on as neutral, destroying one poison and producing another; are the poisons themselves simply removed by currents of air, or are they oxidized in the air; if so, are they oxidized only when ozone is present (see Our Homes, page 11); and if in the air, why not in the blood, after we have rebreathed them and surrounded them with oxygen, in loose combination with hæmoglobin?