Timely Hints for Farmers. 



101 



Rocks, near Tempe, was found by the chemists of the Station to 

 contain excessive amounts of organic matter and ammonia, ar.d no 

 less than 400 times as much nitrous nitrogen as is commonly con- 

 sidered permissible in a drinking water. These substances are 

 not poisonous in themselves, for both men and animals use and 

 sometimes even prefer river water; but these impurities afford 

 food for bacterial forms of life, some of which may cause disease. 



Fig. 10, An adobe hole, or stock water tank, near Phoenix, Ariz. 



Especially in warm weather, where such water is allowed to 

 stagnate in stock water tanks, these germs multiply enormously. 

 Of course a certain disease germ may or may not be present, but 

 such conditions invite and favor its development. There is ro 

 question that the germs of hog-cholera and black-leg, both of 

 which have caused serious losses in Salt River valley, are prop- 

 agated in the stagnant water of these tanks. The doctors state, 

 also, that the same cause is responsible for much disease and mor- 

 tality among the farming population. 



