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THE POPULAR SCIENCE MONTHLY 



Landing Stage for Immigrant Barges at Ellis Island. 



only interest, but must engage the loyal support of every good American. 

 Yet the name itself means the same to no two people, and there exists 

 an equally diverse opinion respecting the relative importance of the com- 

 ponent elements of the public health, and the causal influences con- 

 trolling it. However, it is unnecessary to bring up disputed points and 

 impractical discussions when there are issues of the most vital concern 

 involved in this question. 



The public health, or the health of people en masse, in groups or 

 communities, is more than an adding together of the conditions of 

 health in which each person in the group finds himself. Just as the 

 mob-sense, the group consciousness, or the dominant spirit of the mass, 

 as one chooses to call it, differs from the individual personalities which 

 compose it, so the public health differs from the individual health of each 

 single person. The public health is intangible, though none the less 

 real. It is not a static condition, which can be moved and delimited 

 from without, but it is full of dynamic potentialities, and pregnant with 

 unforeseen complications and denouements. The study of it leads into a 

 bewildering array of intimately related subjects which at first glance 

 seem to bear but a meager relation to it. A survey of its field must 

 begin with an understanding of what is included in the term public 

 health itself. 



Public health may be considered to present itself in three phases, 

 as physical, mental and social health. Each is influenced by many factors. 





