HOW PLANTS BENEFIT AND HARM MANKIND 181 



Even if the disease gets a foothold, it is quite possible to cure it if 

 it is taken in time. The germ of tuberculosis is killed by exposure 

 to bright sunlight and fresh air. Thus the course of the disease 

 may be arrested, and a permanent cure brought about, by a life 

 in the open air, the patient sleeping out of doors, taking plenty of 

 nourishing food and very little exercise. See also Chapter XXIX. 

 Typhoid Fever. One of the most common germ diseases in 

 this country and Europe is typhoid fever. This is a disease which 

 is conveyed by means of water and food, especially milk, oysters, 



How sewage containing typhoid bacteria may get into drinking water : c, cesspool ; 

 Im, layer of rock ; w, wash water. 



and uncooked vegetables. Typhoid fever germs live in the intes- 

 tine and give off a toxin or poison which gets into the blood, thus 

 causing the fever characteristic of the disease. The germs multi- 

 ply very rapidly in the intestine and are passed off from the body 

 with the excreta from the food tube. If these germs get into the 

 water supply of a town, an epidemic of typhoid will result. Among 

 the recent epidemics caused by the use of water containing typhoid 

 germs have been those in Butler, Pa., where 1364 persons were 

 made ill; Ithaca, N.Y., with 1350 cases; and Watertown, N.Y., 

 where over 5000 cases occurred. Another source of infection is 

 milk. Frequently epidemics have occurred which were confined to 

 users of milk from a certain dairy. Upon investigation it was found 

 that a case of typhoid had occurred on the farm where the milk 

 came from, that the germs had washed into the well, and that this 



