COXTKOL OF BACTEIUAL DISEASES 235 



anthrax and glanders, and many others) and the long list of bacterial 

 diseases of plants, already briefly considered, we begin to realize that 

 the very edge of the struggle for existence lies between mankind and 

 the bacteria. 



The three questions. The following questions apply to the 

 parasitic diseases — bacterial, protozoan, vermian, and all the 

 rest. When Pasteur was '' wasting his time " disproving 

 spontaneous generation, one of his friends wrote: ''He makes 

 me uneasy, he does not recognize the limits of science, he 

 only loves insoluble problems." Now that we know that 

 " la generation spontanee est line cldmere^'' the problem of the 

 control of disease becomes the comparatively easy one of 

 preventing the spread of the living germs from the sick to 

 the well. In every case of contagion or infection the germs 

 escape alive from the body of tlie sick, are carried to the 

 well, and gain entrance. Therefore the three fundamental 

 questions are : 



1. How do the germs of each disease escape from tlie 

 body of the patient ? 



2. How is each kind of germ carried ? 



3. How does each kind of germ gain access to the body? 

 Paths of escape. Parasitic germs of the lungs, nostrils, 



throat, or mouth (of diphtheria, tonsillitis, pneumonia, tuber- 

 culosis, rhinitis, bronchitis, and influenza, as well as stomach 

 and intestinal diseases that involve vomiting — typhoid fever, 

 enteritis, and cholera) escape with any discharges from mouth 

 or nose. Careless coughing and sneezing may scatter the 

 germs over anything or anybody within a distance of about 

 six feet. Spitting in any public place is an abc^mination, and 

 laws against it should be rigidly enforcetl in the interests 

 of public education as well as health. 



Bacteria from the digestive and renal-reproductive organs 

 pass out with the dejecta — dysentery, choleras, typhoid. 

 Typhoid bacilli have also been found in the perspiration. 



