of the Old World and.the New World. 167 
herald the air of the tropics and the neighborhood of the Gulf of 
Mexico. 'T'wo thousand four hundred miles separate the extremes 
of this scale of vegetation which almost touch each other in the 
Himalaya. 
It is, moreover, to these vast plains, which offer no obstacles 
to the dissemination of the species, and to the absence of great 
chains from east to west, that we undoubtedly owe the appear- 
ance at the North, of plants and animals that seem to belong only 
to the tropical regions. It is not without surprise that the Euro- 4 
pean landing on these shores sees the humming bird, that diamond J 
of the tropics, glancing in the sun in a countr which winter | 4 
clothes, during long months, in a thick mantle of snow and ice. 
e same towards the South, where we see the palm trees 
and the parrots of the tropics, here and there, as far as the Pampas 
of Buenos Ayres, much beyond their natural limits 
Thus the contrast between the North and the South is soften- 
ed, reduced ; but it is not annihilated; it exists on a great scale 
from one of ‘the continents to the other: for North America is . .# 
temperate, and South America is tropical. “wip 
America is cut by the Andes into two parts, east and west, as -,.. 
Asia and Europe are cut into two parts, north and south. But. ge 
an contrast also is almost neutralized, as we shall soon under- 
and. 
The inequallae” is ive aed to the extreme, to such a ae z; 
tion of one of the parts, that it loses its importance, anya . < 
speak, its power of reaction. The western coast, dry an bare “* 
-has not extent and influence enough to enter upon an effective? % 
rivalry with the vast countries of the East. - Moreover, the dies ie 
ches of communicationstenders the mutual action*and the inte = 
urse between the countries situated at the foot ‘of«the two in- 3 * 
elinatigne sult more. rare. Finally, the two sides Bf the Aides. “7 
ing"u 
differ in the degree of moisture or ZF fall- 
‘nly ait The West of 4 two America 
to"Pe Compared “with the eae 
he entire continent, ant 
os tee, intemal conte tibia the’ ei i ‘ 
ésimple., “Un-"*® 
