excusable, preferring the known horror to the immeasurable unknown. But, to one acquainted with the fact that infinitesimal life swarms about and within us, why should it be terrible to learn that some forms are coincident with disease? If we thrive upon palpitant air, drink water populated with bacteria, and shelter millions of microbes in our bodies, why should we tremble to find a few unfriendly species that we can not safely entertain? We talk glibly of "pure air" and "pure water"; but, to be exact, we have only a laboratory knowledge of either, and might as well try to rid ourselves of our surplus population as to provide ourselves with these elements in a sterilized state.
"Dead" and "undesirable" may be equivalent terms in regard to air and water, but we do not yet know whether they can be applied to food. All of the bacilli that visit our articles of diet seem to herald some fermentative or putrefactive change. Sometimes these are agreeable to us, and we aid them in their work of creating yeast, wine, and kumyss. Even then we watch closely and fix a limit to their activity. Generally, we are squeamish about their advent in meat, milk, cheese, or eggs, having dire experience of the alkaloids that they manufacture. And, it must be noted, it is not the bacilli themselves that give us trouble; for all we know they may be as digestible as the cholera bacillus was to M. Roche Fontaine. It is the physiological result of their sojourn in the food that constitutes the danger—the unfortunate remainder, or ptomaine, that may be fatal to us. This ptomaine is an alkaloid formed from the medium in which the organism exists, and includes whatever substance may be left of the bacterium itself. Just as man changes the atmosphere about him by exhaling carbonic-acid gas and various solid particles of matter, so the bacillus decomposes the tissues and fluids of the body in which it resides.
Nothing more wonderful than this work of disintegration is revealed to us in the economy of Nature. The picture of species after species accomplishing, by a brief life, one step toward the final resolution of organic matter into the elementary products, is not surpassed by a study of the glacial chiseling of the rocks, nor of the marvelous influence of the earth-worm in fructifying the soil.
Obviously, we can not wait for the manufacture of any poison, but must make it an impossibility, if we can, without rivaling any of the toxic effects by our remedies. Acquaintance is occasionally made with the ptomaine before the guilty micrococcus is known; in such cases even more care must be exercised.
Following the investigations of Lister and Hueppe, the ordi-
- A cubic centimetre of wholesome water may contain from 53,000 to 770,000 colonies of bacteria.