Animal Morphology. 143 



in perfect union, or have one mind and will ; or if without 

 mind and will, all has been done exactly as if mind and will 

 were .never absent. 



We now turn to examine vital force in its more general 

 and extensive forms of manifestation, as affecting large areas 

 of the earth's surface ; and the constant ebb and flow of those 

 changes in vital manifestation known as Epidemics. 



EPIDEMICS. 



Vital action, or force, takes a much wider sway than that 

 of merely retaining in integrity the component parts of a 

 system, or interdependent portions of a complete whole or 

 body, for it manifests itself in waves and patches over 

 large areas and in particular parts of the world ; and also 

 its modifying powers are shown in long or short periods of 

 endemic variations, and more widely-spreading changes, 

 called Epidemics; or metamorphic conditions of disease, 

 which are greatly concerned in developing the energies 

 of races, and also in limiting the well-being of habitable 

 tracts of the earth's surface. 



In fact, coupled with duration, change is written upon 

 every portion of the globe ; and metamorphic phases of 

 disease and health are spreading their special stamp of vital 

 manifestation in every historic period ; and each successive 

 generation feels that change, more or less. The bare culture 

 of the ground, the upturning of the soil, the destruction of 

 many kinds of vegetable growth, to be succeeded by one, 

 two, three, or more of a particular kind ; the amount of 

 forest, wooding, fencing, grazing, and cereal yields that any 

 given track of land produces, as well as its manuring, water- 



