286 Epidemics. 



property and cultivated lands, or all things which the hand 

 of man aids in producing. 



The watchful care and knowledge which enables man to 

 plant and gather of the products of the earth, his neighbour, 

 with like care and watchful knowledge, tries to destroy. 



If, then, man's moral force is not, in so great an age of 

 association and combination as is the present anthropo- 

 logical era, kept in check, and guided by some fixed and 

 central ethical and comprehensive benevolent principle and 

 system (and we have it already to hand in the New Testa- 

 ment), the result of great and ramifying association, with 

 the ever-increasing means, by machinery and invention, of 

 bringing that social principle into practical effect from the 

 world's past history, it is quite certain, if the moral system 

 of an enlarged and practical benevolence does not gradually 

 leaven the whole human race, that the vital force, through 

 human devices of a destructive character, will expend itself 

 in covering whole tr acts of land with thorns and briars and 

 rank and useless vegetation, in the place of the rich harvests 

 of corn, and wine, and cattle, and all that is useful to both 

 man and beast. 



Hence, though the digression into anthropology, as given 

 to us in history, may be considered somewhat foreign to a 

 mere sketch of vital force, yet, when it is more carefully 

 examined, a co-relation and balance between the moral and 

 vital force meet in such a culminating point, and frequently 

 in an antagonistic form, that the bare suggestion of their 

 having a common field of action on this small planet of ours 

 is scarcely out of place. 



WE NOW COME TO THE SUPPOSED CAUSE, OR CAUSES, 

 OF EPIDEMICS. 



It will be perceived that neither earthquakes, volcanoes, 

 comets, mildew, swarms of locusts, heavy continued rains, 



