ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 333 



inicroorganic infection and the slow or quick poisoning resulting there- 

 from, or simply to hot and cold air, respectively. 



The diseases resulting from chill, both in hot and cold climates, and 

 the means of guarding against it. 



The effect of climate, both direct and indirect, upon the tendency 

 to nervous diseases and mental diseases, and upon the tendency to 

 suicide. 



The influence of climate, direct and indirect, upon national character. 

 The effect on health of clear, dry, intensely cold calm weather, such as 

 prevails in high latitudes and on high mountains, and the effect of dry, 

 hot climates as distinct from moist. Both hot and cold dry climates 

 seem to be healthy and tolerable. Separation of the malarious disease 

 effects of hot, moist climates from the mere effects of heat aud moisture 

 of the air. 



An investigation of the causes of the healthiness of cold, wet sum- 

 mers in western Europe, and of the means by which some of their 

 beneficial results may be artificially imitated. 



A comparison of the healthiness of the different seasons in the same 

 and different portions of the United States, and of the relation of 

 zymotic and other diseases to the condition of the air, and to the tem- 

 perature of the soil and of the ground air. The variety of climate and 

 extent of surface of North America, and the great system of the Signal 

 Service make that country peculiarly adapted for such an inquiry. 



The reasons of the arrest of certain spreading diseases, such as yellow 

 fever and dengue, by lower temperature. 



The climates and qualities of air most beneficial to persons suffering 

 from nervous diseases, nervous irritability, and heart disease. An 

 attempt at a classification of climates most suitable, in most cases, 

 for each kind of malady or ailment, separating as far as possible the 

 purely climatic from the human factors, such as accommodation, food, 

 etc. The elaboration of a complete medical climatology, applicable not 

 only to persons, robust or invalid, but to families and races, with regard 

 to temporary or permanent settlement. 



An examination of the conditions under which, in the crowded quar- 

 ters of large towns, population deteriorates, so as to become in a short 

 time, if not recruited from the country, physically and mentally 

 enfeebled, and in a few generations almost extinct. The part played 

 by the continual breathing of bad air, and by the crippling produced by 

 attacks of various maladies most rife in crowded places and bad air. 



Contrasted with country air, town air contains an excess of carbon 

 dioxide, less oxygen, no ozone, many gaseous and solid impurities and 

 vapors and an immensely greater number of motes of the finest dust. 

 The air is also heated by pavements, etc., so as to become less bracing. 

 The parts played by these various factors in diminishing vigor might 

 be to some degree allocated. 



The effects, direct or indirect, of daily or constant breathing of viti 

 ated air on the mental powers, the will, self-control, and temperance. 



