Biological Institutions 



75 



families and traits occurring in any locality, and finally to 

 find the location of a given family and the traits peculiar to 

 it. The Office has extensive collaboration with charitable and 

 penal institutions throughout the country, by means of which 

 it obtains very valuable data regarding the occurrence and 

 inheritance of many defects in man, both mental and physi- 

 cal ; and finally it conducts a training school for workers in 

 human inheritance, with a view to preparing them for service 

 in such institutions. 



Baked in the scorching rays of the Arizona sun lies 

 Tumamoc Hill, the Hill of the Turtle in the Navajo tongue. 



Desert Botanical Laboratory 



The deserts of Arizona have been invaded by the biologist, offering 

 as they do a specially attractive field for studies of the influence of 

 environment on both animals and plants. At this station of the Carnegie 

 Institution of Washington at Tucson, Arizona, many important discov- 

 eries have been made as to how plants adapt themselves to a desert 

 environment. 



Courtesy 0/ the Bureau of Commerce of Tucson. 



On its slopes, covered with the rocky debris of some convul- 

 sion of the earth long past, grows the giant cactus, gaunt and 

 misshapen by day, spectral and weird by night. Its summit 

 overlooks a tumbled junk heap of hills and hollows suggestive 

 of the thought that the Creator became hurried at the last 

 moment and did not have time to put the finishing touches 

 on the wilderness. At its foot lies the Santa Cruz Valley 

 with the city of Tucson, and across the valley, sharply out- 

 lined against the deep azure of the desert sky, rise the bold 

 commanding shapes of the Santa Catalina Mountains, with 



