3^ Evolution by Expansion. January, 
This is a case very much to the point. We cannot con- 
ceive a recurrence to ancestral adaptation due to natural 
selection without a distinctly beneficial result accruing from 
it, or without some direct cause for it. The recurrence to 
ancestral forms can only be a recapitulation of earlier types. 
Having thus briefly reviewed the evidence of the leading 
facts of natural history and allied subjects, in reference to 
my theory, I will now arrange what deductions I have 
made from them, in such a form as to afford a clear appre- 
ciation of my position. 
First, I have shown that type is persistent through every 
adaptation to the conditions of existence ; or, in other words, 
that adaptation to the conditions of existence is independent 
of type. From this I infer that conformity to type is due to a 
cause separate and distinct from that which effects adaptation to 
the conditions of existence ; the latter may therefore be the 
result of natural selection, but the former must be due to an 
innate power, — that is, natural selection may modify, but 
cannot originate type. 
Secondly, I have pointed out that a power of expansion 
indubitably exists in all organisms, — that it produces in the 
individual a repetition of the metamorphoses that have oc- 
curred in the race. From this similarity of effect I infer a 
similarity of cause ; i.e., that the race was developed by a 
process of expansion, or unfolding. 
I have, moreover, shown that correlation of growth can 
be satisfactorily explained only on the supposition of cor- 
relative expansion. I have also indicated the impossibility 
of explaining the recurrence of organisms to ancestral 
types in their embryonic or larval stages, on the theory of 
natural selection. 
I may here mention how strikingly the theory of an 
innate force harmonises with the well-known faCt that 
similar forms of life have appeared simultaneously all over 
the world. This is accounted for by Darwin on the suppo- 
sition that dominant species have a tendency to spread 
widely ; but this does not account for the distribution of all 
species with sufficient rapidity to represent this pheno- 
menon ; for instance, terrestrial Mammalia would not 
migrate to any great extent, and very slight barriers would 
confine them to a limited area for generations. 
The phenomenon is, however, decidedly suggestive of the 
gradual evolution of species by some agency aCting at a 
uniform rate throughout the world. 
The appearance at the present time, in similar climates, 
of plants and animals closely resembling one another, and 
