SALUBRITY. 119 



it is central, and, as compared with the other portions of the 

 Atlantic side, a salubrious State ; yet the chances of death 

 from those two main diseases are twice as great there as here. 



88. Malaria. Climatic influence is the chief cause of 

 sickness, and more men die of those diseases which may be 

 classed as climatic, than of all other diseases combined. The 

 climatic ailments are mainly fevers, which carry off from one- 

 fourth to two-thirds of the human race ; and inflammations 

 of the respiratory organs, which carry off from one-sixth to 

 one-third, according to circumstances. The precise manner 

 in which the organs of the human system are thrown into 

 disorder by meteorological influences is a matter of doubt and 

 dispute; but the fungoid theory of disease is now gaining 

 favor the theory that many of our ailments are caused by 

 the growth of vegetable parasites carried into our systems in 

 the form of germs so minute that they float about in the air. 

 These germs of disease multiply with the greatest rapidity, 

 and display the most malignant activity, in a humid and hot 

 atmosphere. 



The principle is universally accepted among physicians, that 

 malignant fevers owe their origin mainly to heat and humidity. 

 We have overwhelming evidence that these two conditions 

 always accompany, or have accompanied, the most fatal epi- 

 demics and endemics, including cholera, yellow fever, vomito, 

 jungle fever, Panama fever, and various forms of plague 

 which formerly raged in Europe, but seem to have entirely 

 disappeared now. The greatest mortality by such ailments is 

 invariably in hot climates, where the rainfall is great, or in 

 warm, wet seasons ; and they are never very destructive in 

 high latitudes or altitudes, or in dry countries. In some trop- 

 ical districts, forty per cent, of all foreigners are seriously sick 

 the first year of their residence, and half of the cases prove 

 fatal ; and even the natives, accustomed to the climate, can- 

 not venture to spend a night in certain unhealthy localities. 

 The migration of business men to and from certain tropical 



