270 BACTERIA, YEASTS, AND MOLDS 



the times when there is most chance of contagion, and 

 that all well persons should, so far as possible, be kept 

 away from the vicinity of these patients at the time of 

 coughing. If this is done and the sputum is cared for, 

 the chance of contagion is much reduced. 



The question often arises how long the isolation should 

 be continued. One must usually depend upon the physi- 

 cian or board of health for an answer to this question, 

 since the period of isolation varies with different diseases. 

 For scarlet fever it is about six weeks ; for whooping cough 

 it is certainly as long ; for diphtheria the time of necessary 

 isolation varies from two to six weeks, and a laboratory 

 examination is necessary to determine when a convalescent 

 patient ceases to be able to transmit the disease to other 

 children. Measles is only contagious in its early stages, and a 

 week after the patient "breaks out " is no longer communi- 

 cable. In general, the period of isolation must be determined 

 for each disease by the advice of physician or board of health. 



Excreta. In the case of diseases located in the alimen- 

 tary canal, and distributed by excreta, isolation of the 

 patient is not so necessary, but everything that comes in 

 contact with the discharges from the alimentary canal 

 should be carefully guarded. This will include not only 

 the discharges from the intestine but also those from 

 the mouth. All possible precautions should be taken to 

 prevent any such material from being distributed through 

 the household. Such diseases can very easily be confined 

 to the patient and the sick room if care be taken with 

 the excreta, if all soiled materials coming in contact with 

 the patient and all eating utensils be thoroughly disinfected 

 by placing them for ten minutes in boiling water. 



