36o BIOLOGY AND HUMAN LIFE 



absolutely prohibit the sale of dangerous drugs except on the 

 prescription of a licensed physician. Another example of pro- 

 hibitive regulation is the amendment to the Constitution, stop- 

 ping the legal sale and manufacture of intoxicating liquors. 



273. The public educates itself. The greatest enemy of the 

 public is its own ignorance. New facts and new problems arise 

 every day. It is impossible to teach in the schools all that the 

 children will need to know, and it is certainly impossible to tell 

 in advance about discoveries that are still to be made. Every 

 progressive community, whether it be a city, a state, or a nation, 

 seeks to increase knowledge and to spread it among its members 

 as quickly as possible. 



In every large city the health department has a staff of men 

 and women whose business it is to make investigations on spe- 

 cial aspects of local health problems. They study the water sup- 

 ply, the milk supply, the markets, the sewerage system, and the 

 disposal of garbage. They conduct experiments for the purpose 

 of increasing the accuracy or shortening the time of diagnosis, 

 for in some cases a few hours may be of great significance. They 

 experiment also for the purpose of improving materials and 

 methods in the preparation of vaccines and serums, and they 

 investigate the relative efficiency of different methods of fight- 

 ing flies or ventilating factories or schoolhouses. 



The state and local departments of health, the experiment 

 stations, and the schools are continually at work increasing the 

 protection of the public, and part of the protection consists in 

 teaching all classes of people to make use of new ideas. The 

 United States Public Health Service has supervision of marine 

 hospitals and conducts special investigations on special diseases 

 and on methods for preventing epidemics. In recent years there 

 has been an increasing amount of cooperation between repre- 

 sentatives and commissions from different countries, seeking 

 to solve health problems on a world-wide scale. 



In the work of all these agencies the distribution of information 

 through bulletins, newspaper notices, pamphlets, lectures, confer- 

 ences, posters, and other means constitutes an important element. 



