PUBLIC HEALTH 85 



land. (Reproduced from studies at Lake Umbagog, New Hamp- 

 shire.) 



This rocky island thirty miles from shore in the Gulf of St. Lawrence 



affords some protection to the sea birds which still nest 



in great numbers on and in its cliffs, although the colony 



is a mere shadow of what it was even fifty years ago. 



Seven species are shown nesting in the group. Namely the razor-billed 



auk, petrel, gannet, puffin, kittiwake gull, common murre and Brun- 



nich's murre. (Reproduced from studies at Bird Rock, Gulf of St. 



Lawrence.) This was the first habitat group. 



[Return to the South Pavilion containing the apes and monkeys.] 



WEST CORRIDOR 

 Public Health 



Returning to the South Pavilion where the monkeys are, and passing 

 to the right, we enter the West Corridor containing the exhibits of the 

 Department of Public Health. 



The Hall of Public Health is dominated by a bronze bust of Louis 

 Pasteur, the founder of scientific bacteriology and preventive medicine, 

 which was presented to the Museum through the courtesy of the Pasteur 

 Listitute of Paris. Near the head of the stairway is a reading table 

 where pamphlets bearing on insect-borne disease and other public-health 

 problems may be consulted. 



The first section of the exhibit deals with the natural history of water 

 supply as it affects the life and health of man. The large 

 Water Supply frieze at the entrance to the corridor on the left illustrates 

 the primary source of water supply, the sea, the clouds, 

 and the secondary sources, rivers and lakes. Diagrams, models, and a 

 relief map show the variations in rainfall at different points in the 

 United States. ReUef maps of the region about Clinton, Massachusetts, 

 before and after the construction of the Wachusett Reservoir for the 

 water supply of Boston, show the way in which surface water supplies 

 are collected by impounding streams, and a model of a well sunk through 

 impervious clay or rock down to water-bearing strata shows how ground- 

 water supplies are obtained. A series of samples and models illustrate the 

 variation in composition which occur in natural waters, from the 

 swamps of Virginia to the deep wells of Iowa and the turbid rivers 

 of the Ohio Valley. 



Some of the principal micro-organisms, Algae and Protozoa, which 

 grow in reservoirs and impart tastes and odors to water are represented 



