Poulton.l 374 |Mayi6, 
which iKiturul st'lertion itself depends; hut heciuise we have not 
yet readied that lower level, we have no reason for douhting, as 
some would believe, the comj^lete efficiency, at its own lerel, of 
the explanation we do happily possess. 
The theory which stands in contrast with natural selection, and 
which has been here supported more fully than in any other civi- 
lized country, with the exception of France, is the theory we 
usually attribute to Lamarck. Erasmus Darwin in England, 
however, has the priority, in that he first brought forward the 
principles which Lamarck more effectively supported. But to 
Herbert Spencer belongs the chief credit, because he has taken 
that part of the earlier theory which is acceptable to modern 
biological thought, and upon this basis has formed his great 
theory of evohition. 
Lamarck believed in an innate tendency toward perfection in 
animals. Now, that is a view which very few zoologists at the 
present time, if any, would dare to sustain. In fact, an evolution 
due to an innate principle of j^erfection is not very much removed 
from the doctrine of special creation which preceded any theory 
of evolution. Herbert Sjiencer, therefore, rejecting all those 
elements of Lamarck, which the scientific world could not 
possibly accept, has taken that which has commended itself to 
science, and upon it has formed his great theory of evolution ; so 
that the Lamarckian theory, as presented to the world to-day, 
comes before it in Spencerian language and in the closest relation 
to Spencerian thought. In saying this, however, I do not by any 
means intend to be understood as supporting Spencer's theories 
or the views upon which he bases them. 
The Lamarckian theory, then, upon which Spencer has based 
his philosophy, is a theoiy of evolution dependent, not like 
natural selection upon three factors, but upon two. It depends 
first of all upon the effect wrought on the individual by that 
which happens during its lifetime. Instead of depending on 
those innate and essential differences upon which natural selection 
rests, this theory depends on those changes which are caused 
during the life of the individual, — the action of some external force 
upon it, the effect of its own will, the changes produced by the 
use and disuse of its own parts. The Lamarckian theory depends 
in fact on all those changes in an individual which we now call its 
acquired characters ; that is, characters which the individual has 
