1877.] Catastrophism and Evolution. 467 
finite branching out and differentiation of the complex forms of 
life from the primitive germs. His theory is natural selection, 
or the survival of the fittest, a doctrine which, left where Darwin 
leaves it, has its very roots in uniformitarianism. 
Analyzed into its component parts, natural selection resolves, 
as is well known, into two laws, hereditivity and adaptivity: 
first, the power on the part of organisms to transmit to offspring 
their own complex structure down to the minutest details ; and, 
secondly, the power by slight alterations on the part of all indi- 
viduals to vary slightly in order to bring themselves into har- 
mony with a changed environment. When we bring geology 
into contact with Darwinism, it is evident that hereditivity is 
out of the domain of our inquiry; it is not the engine of change, 
it is the conservator of the past; but the companion law of 
adaptivity, or the accommodation to circumstances, is one which 
depends half upon the organism and half upon the environment ; 
half upon the vital interior, half upon the pressure which the en- 
vironment brings to bear upon it. Now, environment, as conclu- 
sively shown by biologists, is a twofold thing, a series of compli- 
cated relationships with contemporaneous life, but, besides, with 
the general inorganic surrounding, involving climate and position 
upon the globe. Preoccupied with the strictly biological envi- 
ronment, namely, the intricate relation of dependence of any spe- 
cies upon some of its surrounding species, biologists have signally 
failed to study the power and influence of the inorganic or geo- 
ogic environment. The actual limits of the influence of physical 
conditions on life are practically unknown. In America more 
than in Europe this branch of inquiry has begun to attract no- 
tice, but it is yet in its swaddling-clothes. It has lain little and 
weak from inanition, while the favorite child, Natural Selection, 
has been fed into a plethoric, overgrown monster. Darwin, Wal- 
lace, Haeckel, and the other devoted students of natural selec- 
tion have brought to light the most astonishingly complex strug- 
gle for existence, everywhere progressing — the fiercest battle for 
ife and for subsistence, for standing-room, for breath. Some 
Species gain, others lose, some go down to annihilation. - In this 
battle they seea dequate cause for all the great, highly organized 
products of the millions of years since life began. From their 
ic, you and I are conquerors who have mounted to manhood 
by treading out the life of infinite generations. We are what 
We are because this brain and this body form the most effective 
fighting-machine the dice-box of ages has thrown. 
