214 Inheritance of Acquired Characters 
whose power of growth stands in exact proportion with 
their length? Would the shorter fingers therefore have 
a phylogenetic tendency to become constantly still shorter, 
and the longer fingers a tendency to become steadily 
longer yet? If that were so it would lead directly into 
this absurdity, that the formation in phylogeny of new 
organs or of new structures in general could never have 
any commencement, since originally their determinants, 
just because of the very smallness of these formations, 
must have been provided with only a very small power 
of growth and therefore could never progress side by 
side with determinants which must in any case be 
stronger since they belong to organs or structures already 
developed. 
If on the contrary this is not the case and cannot be 
the case because it contains an unavoidable contradiction, 
then the determinants of any degenerated organ what- 
ever, such for example as the hind leg of the immediate 
ancestor of the whale, cannot be regarded as feebler, but 
must rather be regarded as qualitatively different from 
those of the complete organ. Consequently there cannot 
exist for the degenerated organ any phylogenetic tendency 
to become still more rudimentary. 
Weismann would give, as we have said, a quite 
similar explanation of co-ordinated variations: 
If there were, for example an increase of the weight 
of the head, as a direct result let us suppose of natural 
selection, certain muscles of the body after having 
received an initial impulse from natural selection itself, 
would acquire a phylogenetic tendency to grow pari passu 
with the weight of the head. For the first operation of 
natural selection would be to eliminate individuals whose 
muscles were too feeble. Then even if we suppose that 
