248 NATURAL SCIENCE [October 
highly-developed and more differentiated organisms in animal or 
vegetable kingdoms. While such men as Darwin and, to a less 
extent, Romanes have occupied a more general position, the numer- 
ous almost unconscious impressions that come to an investigator in 
any branch of science, the little details of practical experience which 
are rarely if at all jotted down, even by the most painstaking re- 
corder, give, I believe, a general and correct, though usually uncon- 
scious, colouring to all his work, original or otherwise, and are 
largely influential in determining his convictions. 
It is to this colouring from different surroundings that I attri- 
bute the positions taken up by the various evolutionists, and I 
think, had it been possible for the Neo-Lamarckians and Neo- 
Darwinians to have exchanged positions at the commencement of 
their scientific studies, that both sets of investigators would have 
materially altered their opinions. 
The conclusions drawn, both on theoretical and_ practical 
grounds, from the study of the principal works of both sides, 
seem to me to support the following propositions :— 
(1) That the simpler the organism, the greater the power of 
use-inheritance. 
(2) That the higher stages of evolution entail increased differ- 
entiation, and therefore increased difficulty of direct 
adaptation to environment, and therefore increased de- 
pendence on natural selection. 
(5) That high specialisation must be accompanied by a corre- 
spondinely increased stability, and, therefore, increased 
difficulties in the action of use-inheritance, on account 
of the increased dependence of those specialised parts on 
each other. 
(4) Lastly that, with the increase of natural selection, the varia- 
tions must become increasingly adaptive. 
The second point has special reference to the theories of 
heredity. To anyone who considers for a moment the immense 
importance assigned to automatic, unconscious, and reflex actions 
in Psychology, Physiology, and Pathology, and the large amount 
‘which has been written on habit and its effect on the organism, 
it must seem remarkable that so little importance has been given 
to it in evolution and heredity. Erasmus Darwin considered that 
as the embryo was made up of two portions which had formerly 
belonged to its parents, it was reasonable to suppose that it would 
to a large extent retain the habits of those parents. 
More lately, Professor Ewald Hering has extended this idea to 
.what he aptly defines as unconscious memory. His explanation of 
heredity les between the physiological and morphological schools. 
