MODIFICATIONS OF THE DARWINIAN THEORY. 
389 
EECENT PEOPOSED MODIFICATIONS OF THE 
DAEWINIAN THEOEY. 
ABSTRACT OF PAPER BY WALTER HEAPE, M.A. 
(Read 16th December, 1887.) 
The lecturer prefaced his remarks by reminding the meeting that 
— (1) Darwin did not evolve the theory of evolution, but that he 
sought to explain, by means of his theory of natural selection, the 
origin of one species from another species; (2) that a belief in 
Darwin's theory does not entail a belief in the occurrence either in 
the living or fossil state of species intermediate with any two 
existing species, but it rather entails a belief in the occurrence of 
species, or varieties of species, either living or dead, which are 
intermediate between two or more species and their common 
ancestor. 
The evidence which Darwin brings forward in favour of his 
theory was then shown to demonstrate — 
1. The tendency in all living things to vary. 
2. The tendency in all living things to inherit the peculiarities 
of their ancestors. 
3. The power of living things to adapt themselves to cir- 
cumstances. 
4. The struggle for existence ; natural selection, sexual selection. 
The views of Mr. Frank Dixon, as stated in his book, Evolution 
without Natural Selection, were then discussed; viz., The influence of 
1. Isolation. 
2. Climate. 
3. The use and disuse of organs. 
4. Sexual selection. 
5. Interbreeding and crossing. 
It was pointed out that Darwin's views were not only not 
opposed to Dixon's theories, but that the latter were included in 
the former ; and the fact elucidated that Dixon only differed from 
