176 Review of Darwin’s Theory on the Origin of Species, 
the geological record” (chap. 9), which we suspect is scarcely ’ 
exaggerated, the author considers the geological succession of 
organic beings (chap. 10), to see whether they better accord with | 
the common view of the immutability of species, or with thit | 
of their slow and gradual modification. Geologists must settle : 
that question. Then follow two most interesting and able chap- | 
ters on the geographical distribution of plants and animals, t 
summary of which we should be glad to cite; then a fitting 
chapter upon classification, morphology, embryology, &e,, a 
viewed in the light of this theory, closes the argument; the 
fourteenth chapter being a recapitulation. 
The interest for the general reader heightens as the author ad- 
vances on his perilous way and grapples manfully with the most 
formidable difficulties. 
natural selection. He does “not doubt that the theory ad 
Scent with modification embraces all the members of ye 
class,” and he concedes that analogy would press the i 
still farther; while he admits that “the more distinct the , 
are, the more the arguments fall away in force.” To commail 
assent we naturally require decreasing probability to nent 
balanced by an increased weight of evidence. re ager 
might plausibly, and perhaps quite fairly, urge that aoe 
: 5; chain of argument are weakest just where the greatest" 
$ upon them. he 
To whieh Mr. Darwin’s answer is, that the best paris of : 
testimony have been lost. Ife is confident that int ae | 
forms must have existed; that in the olden times when + stocks — 
era, the families and the orders diverged from their age ‘i at 
gradations existed as fine as those which now oon an id 
related species with varieties, But they have er to viel, 
- ternate chapters have been lost out, or rather which were 
Printed from the autographs of nature. The record wander oe a 
made in fossil lithography only at certain times ap q places of ’ 
‘ain conditions (i, ¢., at periods of slow subsidence and pia 
