906 EDWARD C. SCHNEIDER 



sensitive to slight' temperature changes." James is of the opinion that 

 an even temperature lowers the tone of the vasomotor system by lack 

 of proper exercise. In drier tropics, cooled by trade winds, as found in 

 the Hawaiian Islands, the white population lives and carries on business 

 in "American style" without signs of tropical enervation and deteriora- 

 tion. It appears that many elderly persons and others who are over- 

 worked may find rest from nervous tension in portions of the tropics. 



Extraordinarily low temperatures are easily borne if the air is still 

 and dry, and large ranges in temperature are well tolerated when the air 

 is dry. On the other hand, cold air with a high moisture content has a 

 depressing effect. At the margins of the polar zones the change from 

 winter to summer is so sudden that the transitional season disappears. 

 Hence, in the seasonal changes the intermediate periods that add so much 

 to human efficiency are lacking. 



It has been suggested that unless invalids are of very delicate constitu- 

 tion, or greatly run down in health, the bracing qualities of a northern 

 winter in a dry climate under proper safeguards will probably do them 

 more good, though at times they will be less comfortable, than a warm 

 southern atmosphere. Too large variations of daily temperature may be 

 overtrying, but as a rule a definite drop in the daily temperature is a 

 necessity for stimulation. 



Altitude 



The mountain and high plateau are characterized by a similar climate 

 in all the geographical zones. The characteristics are decrease in pressure, 

 temperature and absolute humidity ; an increase in the intensity of sun- 

 light and radiation; and larger ranges in soil temperature. The climatic 

 action of the heat, humidity and light have been discussed, leaving only 

 the factor of pressure for consideration. Some maintain that the real 

 benefit of mountain climate to the health seeker is to be found in the 

 favorable heat and humidity and the mental reaction to the beauty of 

 the environment. 



An early suggestion made by Jourdanet is still to be borne in mind 

 when mountain and high plateau climates are recommended. He divided 

 these climates into the mountain climate, below 6,500 feet, and altitude 

 climate above that height. The former was considered beneficial because 

 of the stimulating quality of clean, clear, cool air and the latter injurious 

 because of low pressure. Men live comfortably and work well in the 

 mines of the Andes at 15,400 to 16,200 feet. Such altitudes, however, 

 are for the robust and not the health seeker. 



Residence at a high altitude brings about striking and definite physio- 

 logical changes in the body. There have been many opinions held as to 

 the essential cause. A common belief has been one that regarded the 



