76 G. F. C. SEARLE, M.A., F.R.S.. ON THE 
help of variations of the discontinuous kind. By this process 
there can arise at a single step new forms which have already 
the complete and definite character usually associated with a 
species specially adapted to particular conditions.” There is 
nothing speculative about these abrupt variations or mutations, 
for they have been frequently observed and are more common 
than was formerly supposed. An exainple is furnished by the 
Shirley poppy. “In 1880 the Rev. W. Wilks, Vicar of Shirley, 
near Croydon, noticed among a patch of common wild field 
poppies growing in a waste corner of his garden a solitary 
flower with petals showing a very narrow border of white,” 
and from the seeds of this flower the strain of Shirley poppies 
originated. 
These mutations of living forms bring us back again to the 
idea of abrupt steps which we discussed earlier in the paper. 
No way, apparently, is known of causing these mutations to 
appear; all that can be done, and what is done by practical 
breeders, is to watch for them and to give them every chance 
when they do appear. 
It was thought at one time that the value of an individual 
was as nothing compared with that of the race. But the facts 
of mutation show that this estimate needs revision. For any 
living creature may have an offspring which may exhibit 
mutation and so may be the progenitor of an entirely new race. 
One of the most remarkable results of recent experimental 
work is the recognition of the fact that each living organism is 
no longer to be regarded as a unit but as a composite being 
made up of a great number of unit characters, each capable of 
separate description and all inherited independently of one 
another. 
The manner in which these unit characters are inherited was 
discovered about 1865 by Mendel, first a member and then the 
Abbot of Brunn. The change which the recognition of unit 
characters and the discovery of Mendel have “brought about 
has been described by Mr. Lock as follows :—* On the mind of 
a biologist familiar with what was known of heredity only ten 
years since, these facts must fall with a sense of complete 
novelty. The ideas current even so short a time ago are not 
so much extended, or even altered, as replaced by an entirely 
new set of ideas. And it may be remarked in passing that the 
biologist of fifty years ago and more was much nearer to our 
present line of inquiry 
$15. The Fate of Living Organisms.—From the creation of 
living organisms we may pass to their fate. Though they die 
