212 THE POPULAR SCIENCE MONTHLY. 



excusable, preferring the known horror to the immeasurable un- 

 known. 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 our- 

 selves 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. Some- 

 times 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 ex- 

 perience 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 exhal- 

 ing 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 occa- 

 sionally 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 Y^OOO colonies 

 of bacteria. 



