Asiatic Cholera 113 



the same risk of infection one individual may 

 be attacked with the disease and another not. 

 But alike in all these forms of bacterial 

 disease the particular species of bacteria 

 belonging to each must be present, predispo- 

 sition or no predisposition, or the disease 

 cannot occur. 



Typhoid fever and cholera are often called 

 filth diseases, and to bad food, foul air, sewer 

 gas, and overcrowding, their occurrence has 

 often been attributed. This is in a sense 

 true, since these adverse conditions are apt 

 to induce a state of the body which renders 

 it less resistent than it should naturally be 

 to various deleterious agencies. But no im- 

 aginable degree of unsanitary conditions could 

 ever induce tuberculosis, or typhoid fever, or 

 Asiatic cholera without the presence of the 

 particular germ which causes each. None 

 of these diseases can spring up among any 

 class or condition of people without the in- 

 troduction of the germ from outside. 



The recently acquired knowledge of the 

 cause of Asiatic cholera has thus far aided 

 but little in the treatment of persons already 



