in wuts relations to that of North America. 195 
The facts presented in the present memoir effectually di 
of this subsidiary hypothesis, by showing that the supposed 
single exception belongs to a not uncommon case. Indeed, so 
many species are now known to be common to Kastern and 
Northern Asia and Eastern North America,—some of them oc- 
curring also in Northwestern America and some not,—and so 
many genera are divided between these two regions, that the an- 
tecedent improbability of such occurrence is done away, and 
more cases of the kind may be confidently expected. However 
others may regard them, it is clear that De Candolle would now 
explain these cases in accordance with the general views of dis- 
tribution adopted by him, under which they naturally fall,—so 
abandoning the notion of a separate creation. ; 
know not whether any botanist continues to maintain 
_ Schouw’s hypothesis. But its elements have been developed into 
a different and more comprehensive doctrine, that of gassi 
which should now be contemplated. It may be denominated 
the autochthonal hypothesis. : a 
In place of the ordinary conception, that each species origin- 
ated in a local area, whence it has been diffused, according to 
circumstances, over more or less broad tracts,—in some 
means and facilities for dissemination, as most plants and ani- 
mals. Why then should we supp » the Creator to do that su- 
pernaturally. which would be naturally effected by the very 
* 
