41 
day may be indicated as survivals of the fittest to come up, 
grow, lose the characters of the originals, or assume others 
strange to them. And so, the question comes to be, For 
what purpose are they the fittest ? Certainly not for that 
served by them in their own natural conditions. Neither for 
that served by those indigenous. But the expression, so 
long as it is used in an abstract sense, serves its purpose. 
15. The processes alike of development, growth, and decay 
of plants proceed with the greatest degree of rapidity the 
nearer their locality approaches the equator. Everywhere in 
those regions forest vegetation is rank and luxuriant ; every- 
where do decay and decomposition taint the hot, damp 
atmosphere, the lower organisms of plant life preying upon 
and accelerating the destruction of the higher. There being 
little, if any, difference of season or of atmospheric con- 
ditions, there is not, as in temperate regions, cessation at 
regular periods or at any period to these processes. Life and 
death proceed side by side, creatures of the animal world 
suited to the locality and conditions inhabit the rivers, swamps, 
and forests. Human inhabitants there are too in many such 
localities, though not in all ; but in them intellectual man 
exists not indigenous. 
16. Food plants differ in their genera, and in several other 
particulars, according to geographical position, including 
climate. In tropical regions rice, for the most part, flourishes 
in low-lying, swampy tracts, although what is named hill-rice 
is an exception ; maize, or Indian corn, upon less swampy, but 
alluvial soil ; millets of several kinds, and eleusine (in Madras 
called by natives, ragi), on the dryer kinds of soil. For 
temperate climates, as in that of England, the relation of 
particular kinds of cereal and other crops to local conditions, 
alike of soil and climate, determines to a great extent the 
success or failure of the agriculturist. 
So it is also in regard to fruits. These, even when of the 
same species, differ in respect to size, shape, colouring, flavour, 
and in other respects, according to climatic conditions. This 
applies equally to tropical and to temperate climates. Nor 
are medicinal plants exceptional in these respects. Their 
active properties differ according to local climate and soil. 
And similarly with beverage-yielding plants — the tea shrub, 
coffee shrub, and so on — their produce varies in quality and 
flavour infinitely. 
17. The entire succession of phenomena which occur in 
plant life is connected with, and dependent upon, season ; 
but this relation is not alike as regards all genera. By the 
order in which the several stages of vegetable existence 
