168 
ARE SOILS ENRICHED, IMPOVERISHED, [Part III. 
rate, Nature seems purposely to have contrived 
different stations with similar physical conditions, 
in order to exhibit the profuseness of her crea¬ 
tive power in cramming all full of animal and 
vegetable existences, with constitutions similar 
to those of similar but separate stations, but the 
species of each similar separate station differing 
entirely from the species of all other similar 
separate stations. These stations are in general 
kept separate by what Buffon called “ natural 
barriers.” Besides the difference of climate re¬ 
sulting from difference of latitude, difference of 
altitude, and seas of water, or of sand, or of 
eternal snow, in general separate terrestrial dis¬ 
tricts. Continents, currents, difference of depth, 
saltness, freshness, or temperature of the water, 
separate aquatic districts. M. Alph. De Can¬ 
dolle, son of the great De Candolle, enumerates 
twenty-seven great nations of distinct indigenous 
aboriginal plants. That the plants and animals 
of such vast districts of stations as America and 
Australia should be different from those of 
every other part of the globe, from which they 
are so completely divided, does not strike one 
with so much astonishment as that there should 
be “ found one assemblage of species in China, 
another in the countries bordering the Black 
Sea, and a third in those surrounding the Me- 
