CHANNELS OF INFECTION 17 



In smallpox, scarlet fever, and the " eruptive fevers" 

 generally infectious material is given off from the sur- 

 face of the body of the sick person. This is associ- 

 ated with cast-off epithelium, pus cells, etc., and 

 constitutes a kind of dust which abounds in the sick- 

 room and clings to the clothing and bedding of the 

 patient and of those in attendance upon him. In 

 influenza and whooping-cough the patient forcibly 

 ejects small masses of mucus which soon become 

 desiccated and are likely to make up a portion of the 

 dust in apartments occupied by such patients. Evi- 

 dently the great danger from infection in these dis- 

 eases results from visiting the sick-room or handling 

 clothing which has been exposed to contamination by 

 infectious material coming from the body of the sick 

 person. 



In typhoid fever, Asiatic cholera, and dysentery 

 the infectious material coming from the sick person 

 is contained in the discharges from the bowels and 

 is usually quickly removed from the sick-room. The 

 great danger as regards the spread of these dis- 

 eases consists in the possibility that ignorant or care- 

 less persons may throw these discharges upon the 

 ground or dispose of them in some way which makes 

 it possible for the germs to be washed into a well or 

 a running stream from which water is used for drink- 

 ing purposes. But this is not the only way in which 



