BACTERIA IN DISEASE. 159 



it is no longer possible or very desirable to draw the line 

 sharply between them. Fomites are the materials on which 

 the contagious element is conveyed. 



A miasmatic disease is a variety of infection in which 

 the microorganisms are not received from another case of 

 the disease, but are derived from the external world, par- 

 ticularly through foul air. 



The following is a list of the most important diseases of 

 man caused by bacteria. The proof as required by the 

 rules of Koch is not complete for all of them : 



Tuberculosis, Gonorrhea, 



Leprosy, Chancroid or soft chancre, 



Glanders, Lobar pneumonia, 



Anthrax, Influenza, 



Tetanus, Diphtheria, 



Malignant edema, Typhoid fever, 



Bubonic plague, Dysentery (not amcebic dys- 



Malta Fever, entery), 



Suppuration and certain Asiatic cholera, 

 inflammatory conditions Relapsing fever, 



allied to it, Rhinoscleroma (?), 



Erysipelas, Actinomycosis. 



Malaria and amoebic dysentery are caused by microscopic 

 animal organisms (protozoa). It has been claimed that 

 small-pox is caused by protozoa; this view has acquired 

 added interest from the recent researches of Councilman. 

 Recent work indicates that the " sleeping sickness " (of 

 Africa) and yellow fever may be caused by protozoa (see 

 appendix). Thrush and certain parasitic skin diseases are 

 caused by fungi of more highly organized structure than 

 bacteria. 



In each of the following diseases there is good reason to 

 think that the cause is some kind of microorganism, but it 

 has not yet been discovered : 



