THE INFLUENCE OF URBAN AND RURAL ENVIRONMENT 37 1 



one farmer supplies ten families, two persons only handling 

 the milk. Each member of those ten famihes is exposed to 

 the possibiHty of infection from two persons. But if fifty 

 farmers bring milk to a central plant where it is mixed, 

 stored and sent out to 500 famihes, a total of 150 persons 

 handhng the milk at various stages, the exposure of each 

 individual user to a possible source of infection is now 

 increased seventy-five fold, and a large outbreak of disease 

 now becomes a definite possibility. Nevertheless, the general 

 use of unpasteurized milk in the rural districts is doubtless 

 one of the factors contributing to the higher rural typhoid 

 fever and dysentery rates. 



A secondary result of the higher and more uniform 

 standards of safety of the milk in cities is the increase of the 

 per capita consumption of it by city residents. The more 

 rehable the city milk supply the more does it enter into 

 the dietaries of the people, and the city dweller is approach- 

 ing an optimum use of milk, with resultant benefits to his 

 health and economy for his pocketbook. 



It is evident from study of the prevailing diseases of the 

 Porto Ricans and of our native American Indians that in 

 spite of favorable rural environmental factors in other 

 respects, they are suffering severely from the lack of milk, 

 particularly for their children. 



LIGHT 



Light as a factor of environment, quite apart from the 

 accompanying effects of warmth, or radiation, or specific 

 nutritional effects, bears directly upon the differences of 

 urban and rural life, the dweller in towns submitting to 

 physiological disadvantages from the use of articificial 

 lights to which the human eye is not fully adapted, which 

 the rural resident does not have to suffer. We have no 

 information which can carry us at present beyond the stage 

 of general impression, but it would seem that the artificial 

 conditions of lighting that prevail indoors, in transit, in 

 factory and office, in kitchen, nursery and school, in church, 

 theater and club, in cities constitute a physiological handicap 

 to the function of vision even if no other harmful effect 

 can be determined. 



