420 REVIEWS. 
ing possesses modifications which are exceedingly disadvantageous; thus 
they must either regain the original characteristics of their ancestors or 
become extinct. 
n treating of mimicry, or the protective resemblance which many in- 
sects have to the bark and leaves of trees, Mr. Wallace is particularly for- 
cible and happy in his illustrations. The Kallima inachis and K. paralexta 
c 
these insects never alight except on withered bushes, they are almost 
sure to escape detection. ** We thus have size, color, form and habits all 
cause of variation. 
fore natural selection can act. Thus in the jail et of all ste 
i c 
wit 
e same locality. Again, as cited by i Danger the rise of à mountain 
lirai and corresponding revolutions in the flora and pope of a a EM 
upon with equal facility by physical causes, natural selection being only 
the secondary means by which these variations are perpetuated or trans- 
ferred from individual to individual. 
To our minds one of the most remarkable portions of this book is the 
bold and successful application of the theory to man, and the last chapter 
1 n 
It is shown that natural selection nore cease act upon the body 
after man had once reached a period at which am gari tnu ralio 
began to — since then all eae for farther physical change 
would be at 
(Fn cei nnn: Wang *ind$aK &. + "n + logists this 
ipe. M <i 3 PAEA ird ; si ; but 
peri el Y i q in at a period so remote in his 
