RANGE AND DISTRIBUTION OF MICROBES 6 1 



isms, such as protozoa. So-called pure milk contains comparatively more 

 microbes than pure water. The average good milk contains as many 

 as 30,000 microbes per cc. Filthy milk may contain millions of microbes 

 per cc. From 100,000 to 3,000,000 microbes per cc. is not uncommon in 

 some milk which careless dairymen declare to be "good." Soups, broths, 

 etc., boiled squash, potatoes, meats, and cooked organic substances gener- 

 ally, if allowed to stand for a day or two, contain many living microbes. 

 In the course of two or three days, if the weather is warm, these substances 

 teem with microbes and are rendered wholly unfit for human consumption 

 because of rotting microbes which develop highly poisonous ptomaines 

 and toxins. 



Microbes do not grow and multiply in antiseptic substances, such as 

 strong solutions of acids, of alkalies, of salts, etc. Used and dirty cups, 

 drinking vessels, milk bottles, dishes, cooking utensils, knives, spoons and 

 forks, hold numerous microbes. The public drinking cup has been the 

 source of numerous disease infections. Disease is carried by the tools of the 

 careless dentist and by the clothing, the apparatus and the clinical thermom- 

 eter of the indifferent and careless physician. The hand-shaking and kiss- 

 ing habits spread disease. These facts are generally known and indicate 

 the wide dissemination of the different kinds of microbes. 



From the foregoing it becomes clear that microbes are present almost 

 everywhere, and that it is impossible to escape them. It is the aim of the 

 science of bacteriology to distinguish between good and bad microbes, 

 between those which are desirable and those which are undesirable, be- 

 tween useful and harmful microbes. It is not the aim of the science of 

 bacteriology to destroy them all, or to devise ways and means to escape 

 from all of them. In fact, we owe our very existence to these very minute 

 organisms, as has already been explained. 



Under certain conditions bacteria multiply very rapidly. Such sub- 

 stances as meat, milk, and organic foods of all kinds, if exposed to moisture, 

 warmth and removed from sunlight, soon swarm with microbes. Certain 

 non-pathogenic microbes, as the root nodule bacteria (of theLeguminosae), 

 multiply very rapidly within the tissue cells. Others multiply upon the 

 exterior of roots and of root hairs, where they no doubt serve a useful pur- 

 pose to the plant. In bacterial diseases of plants and animals the microbes 

 multiply very rapidly and form large aggregates , as a rule . To pathological 

 conditions accompanied by extensive and general bacterial or microbic inva- 

 sion, we apply the term bacteremia. In some diseases the microbic 

 invasion remains localized and yet there are pronounced general or sys- 

 temic effects, due to the absorption, into the system, of the toxins liberated 

 by the microbes. To such conditions we apply the term toxemia. Toxe- 

 mia may, however, also occur in bacteremia. 



