CONTAMINATION OF THE AIR 235 



from the coughing of persons with disease of the respira- 

 tory tract, must also be reduced as much as possible, 

 through a combination of education and active measures 

 of repression by legally constituted health authorities. 

 (Hence " Don't spit " ordinances.) 



Direct Infection can be controlled by quarantine, 

 that is, by isolating the affected persons until the organ- 

 isms of disease within their bodies have been destroyed. 

 Quarantine measures are not difficult to enforce, pro- 

 vided the disease is discovered in time by the authorities. 

 The difficulty here is that mild cases are apt not to come 

 to the attention of physicians and so fail to be reported. 

 Thorough-going medical inspection in the public schools 

 is an important aid toward the control of contagious 

 disease. 



