GRADATION AMONG ANIMALS. 101 
Surely not that the connection between animals 
is a material one; for the same kind of relation 
exists between lower and higher animals of one 
type or one class to-day, in their structural fea- 
tures, in their embryological growth, and in their 
geographical distribution, as we trace in their 
order of succession in time; and therefore, if 
this kind of evidence proves that the later ani- 
mals are the descendants of the earlier in any 
genealogical sense, it should also prove that the 
animals living in one part of the earth at present 
grow out of animals living in another part, and 
that the higher animals of one class as it exists 
now are developed out of the lower ones. The 
first of these propositions needs no refutation ; 
and with regard to the second, all our investiga- 
tions go to show that every being born into the 
world to-day adheres to its individual law of life, 
and though it passes through transient phases of 
growth resembling other beings of its own kind, 
never pauses at a lower stage of development, 
or passes on to a higher condition than the one 
it is bound to fill. 
If, then, this connection is not a material one, 
what is it? —for that such a connection does ex- 
ist throughout the Animal Kingdon, as intimate, 
as continuous, as complex, as any series which the 
development theorists have ever contended for, is 
not to be denied. What can it be but an intel- 
