154 Book Notices. 
theories brought forward to explain that change; the definiteness of 
ive, 0 lim- ~ 
their respective groups, be they ever s prehen r ever so lim- 
ited, combined with the greatest inequality in their numeric relations. 
There exist a few thousand Mammalia and Reptiles, and at least three 
times their number of Birds and Fishes, There may be twenty thou- 
boundaries, Now the supporters of the transmutation theory may me 
: : 
not a Bird, since there are other animals besides Birds in this world, to 
no one of which any bird bears as close a relation as it bears to its own 
class, e same argument applies to every other class; and as to the 
together Corals and of 2 d 
era in each successive geological formation, and this is equally true for 
Bryozoa, Brachiopods and Lamellibranchiata, for Trilobites and the other 
hat n | i 
them, I shall therefore consider the transmutation theory as a jentific 
mistake, untrue in its facts, unscientific in its method, and mischievo" 
ency, 
Cambridge, June 30, 1860, 
a ae ces 
