186 THE DARWINIAN THEORY, 
can know the exact character of a common ancestor of a group 
(p. 189); which might, indeed, be stated with greater plainness of 
speech, that we never can know anything at all about it, for all these 
progenitors of groups are creatures of the imagination which we can 
neither discover nor describe. 
Thus, however, is the doctrine unfolded, “if we suppose that the 
ancient progenitor, the archetype, as it may be called, of all mammals 
had its limbs constructed on the general pattern for whatever portion 
they served, we can at once perceive the plain signification of the homo- 
logous construction of the limbs throughout the whole class " (p. 966). 
By this contrivance Mr. Darwin persuades himself that he has ac- 
counted for the appearance of homologous parts in the organization of 
all mammalia, but how evident it is that this is merely removing the 
difficulty to a greater distance, in the remoteness of geological time, as 
if it were out of the reach of logic in that ultra-mundane obscurity! 
We are told that the ancient progenitor of all mammalia had ifs limbs 
constructed on a general pattern. Had its limbs constructed! how 
were they constructed? Had this progenitor no parents? were the 
parents of this first mammalian not themselves mammals? — Did it not 
inherit its nature, form, character, organization, and life from its 
parents, and must it not have been just such an animal as they were ? 
or was the law of inheritance suspended in its favour, and did it come 
into the world a creature formed altogether on a different plan, and 
specifically distinct from its parents? This really seems to be Mr. 
Darwin’s idea, that these progenitors came into being new creatures at 
once; they were not begotten and they were not created, and they did 
not spring from spontaneous generation—neither could natural selec- 
tion have made them, for they were perfect archetypes all at once. All 
we can say about them is, that they existed without cause, and came 
into life unconnected with any previous life. 
If, however, this should be a statement to which Mr. Darwin would 
object, then the other alternative is not to be avoided,—that the sup- 
posed progenitor of a group inherited its organization from its parents, 
in which case it could not be the progenitor of any group or genus, for 
its parents were the same animals as their progeny, and so onwards, in 
backward series, ad infinitum. 
In other words, a progenitor of a group is impossible, unless it were 
created; but this is a supposition wholly inadmissible in the. theory ; 
