Epidemics. II 



Trades and vocations are not exempt from this general 



condemnation, in certain branches. Neither are habits or 



% 

 vices, which entail] on offspring the residuum of their 



general morbific or depressing tendencies over vital power, 

 any less exempt from the same censure. 



Geographical position, and geological strata, have also a 

 very marked effect upon localising defects in special organs, 

 or constitutions. 



These several agencies are in their nature more or less 

 purely endemic, but the wider spread and all-pervading 

 influence of recurring epidemics, is but the limiting of vital 

 power in a consecutive and more general manner, by some 

 form of disease which endemic speciality has already' en- 

 dorsed, or which, through the law of change written upon 

 Nature, it has failed to engraft upon any special point 

 at its first appearance ; but when once cast widespread by 

 the winds of heaven, it never fails to appropriate some 

 special localities as endemic haunts. 



Of those agencies which tend to develop and extend disease, 

 or promote health, as external agents to the earth's surface, 

 the Sun takes the highest and foremost ground. 



The Equator and the Arctic regions have the sun's rays 

 alike in the entire year. The diurnal variation is extreme, 

 and the direction of the sun's rays is very distinct between 

 the Tropical and Arctic regions, though in the entire year 

 the mere amount of rays from the sun is identical, upon 

 any particular part of the earth, but the obliquity 



