IRature IFlotes : 
Ube Sclbovnc Society’s flftagasine 
No. 18. 
JUNE 15, 1891. 
Vol. II. 
SURVIVALS. 
N previous communications to Nature Notes (vol. i., 
p. 169, vol. ii . , pp. 7 and 63) I endeavoured to show 
how plants can vary in the structure of their several 
organs when their environment is altered; and that 
this is due to a responsive power in the living protoplasm, 
which is, so to say, awakened or called into action when the 
surrounding conditions or medium is sufficiently changed. 
This capability of self-adaptation to new circumstances gives 
us reasonable grounds for believing such to be, in brief, the 
means which nature has adopted for bringing into existence new 
species by the process called evolution. It must be borne in 
mind, however, that this doctrine does not assert that all plants 
and animals must be always undergoing changes ; for there are 
many which, having through successive generations acquired 
certain specific characters, have retained such, often for incal- 
culable ages. This fact applies to some animals as well as 
plants. Indeed, there are probably few large groups of beings 
in which some species or at least a genus (if the species it 
contain be different) which has not at least one “ survival ” 
among their community. 
The most obvious explanation is in accordance with -the 
above supposition of the origin of species, namely, that either 
these survivals have never been subjected to very or sufficiently 
different environments, or else they are peculiarly insensitive to 
changes. Just as breeders of cattle and cultivators of plants find 
great differences in the powers of animals and plants to change 
under the very altered conditions of domestication. Some are 
highly “ plastic,” others are “ refractory.” Such differences 
may be called specific idiosyncracies, for one cannot tell why it 
is so ; but only recognise it as a fact. Similarly some genera in 
the wild state run into an immense number of species, sub- 
