BACTERIA AND DISEASE 329 



died of typhoid or other fly-borne diseases while only 

 300 were killed by Spanish bullets." 



Since contagious diseases constitute so serious a menace 

 to human welfare it is necessary to have laws to regulate 

 the treatment of contagious cases, so that they may be 

 prevented from infecting others. People with such dis- 

 eases are often put in quarantine until danger of spreading 

 their infection is past. Immigrants are examined for con- 

 tagious diseases and detained for a certain period before 

 being allowed to land. Through these means many 

 epidemics have doubtless been averted which otherwise 

 would have destroyed thousands of lives. In cities and 

 towns boards of health and health officers look after the 

 enforcement of regulations for checking disease, and 

 for securing general sanitary conditions. 



The correct diagnosis and treatment of disease demands 

 expert knowledge and special training, and states have 

 wisely framed laws requiring that those who occupy 

 themselves with the very responsible business of the 

 physician or surgeon should have received adequate in- 

 struction for carrying on their work. Even the best 

 physicians sometimes make mistakes, but the ignorant 

 or careless charlatan does little but harm. Requirements 

 for obtaining a license to practice medicine are steadily 

 being raised but there are still many incompetents in the 

 regular profession and many quacks who contrive to evade 

 the law and carry on a lucrative trade. One of the favor- 

 ite devices of the quack is advertisement. Newspapers 

 commonly contain several advertisements of the wonder- 

 ful skill and success of various doctors who often pretend 

 to cure ills for which no remedy has ever been discovered. 

 It is a safe rule to avoid all so-called doctors who advertise, 

 for the great majority of them are unprincipled charlatans. 



Numerous frauds are imposed on the public through 



