CONTROL OF INFECTIOUS DISEASES. 697 



outbreak. No more delicate task confronts the public health official 

 than the making of this decision. 



In diphtheria, the examination of cultures from the throat and nose 

 of the person in question and the repeated failure to find the bacterium 

 of diphtheria is usually considered a safe criterion. In scarlet fever, 

 complete and continued restoration of the throat and nose to normal 

 conditions, together with absence of ear discharges, should be required, 

 yet is not perfect; for it is not very likely that the scarlet fever infective 

 agent, whatever it may be, can continue in a recovered scarlet fever throat 

 as the diphtheria bacterium may remain in a recovered diphtheria throat. 

 In other diseases the decision is based on similar lines the disappear- 

 ance of crusts in smallpox and chickenpox, of discharges in measles, on 

 restoration to normal of whooping cough; but in all these diseases the 

 analogy with diphtheria may hold to a greater or less extent. In tuber- 

 culosis, the patient is infective as long as Bad. tuberculosis can be found 

 in the sputum; in typhoid fever the patient is likewise infective as long 

 as the urine or faeces show the typhoid bacillus. In none of these 

 diseases, however, is quarantine or even isolation officially carried out 

 nor release from restriction officially given. 



Full sanitary nursing precautions regarding a typhoid fever patient's 

 discharges should continue for an average of three months after recovery. 



DISINFECTION. 



Two systems of disinfection have been long recognized, concurrent 

 and terminal. The former concerns the daily, hourly attention to, and dis- 

 infection of, everything coming in contact with the patient, especially with 

 his discharges and all that they may contaminate. The latter concerns the 

 final disinfection of the patient's room, perhaps of the whole house, 

 occupied by him during the attack, after the recovery of the patient. 



Much very undue emphasis has been given to terminal disinfection. 

 Large expenditures are made for this purpose and great faith placed in it, 

 unfortunately to the exclusion of attention to, and reliance on, the infinitely 

 more useful and logical concurrent disinfection, which, properly done, 

 ought almost wholly to displace it. 



Terminal disinfection should be done following tuberculosis of the 

 lungs, anthrax and plague, in tuberculosis because of the great numbers 

 and wide distribution of the bacteria thrown out by the patient, especially 



