140 THE THEORY OF MUTATION 
‘He (man) often begins his selection by some half- 
monstrous form, or at least by some modification pro- 
minent enough to catch the eye or to be plainly useful 
tohim.’ But he goes on: ‘ Under Nature, the slightest 
differences of structure or constitution may well turn 
the nicely-balanced scale in the struggle for life, and 
so be preserved.’ * 
Of the origin of a new type of plant in this definite 
and sudden fashion, the Shirley poppies afford an 
excellent example. These originated in a mutation 
of the common wild field-poppy (Papaver rheas). In 
1880 the Rev. W. Wilks, Vicar of Shirley, near Croydon, 
noticed among a patch of this plant growing in a waste 
corner of his garden a solitary flower, the petals of 
which showed a very narrow border of white. The 
seeds which this flower produced were sown, and next 
year, out of about two hundred plants, there were four 
or five upon which all the flowers showed the same 
modification. From these, by further horticultural 
processes, the strain of Shirley poppies originated. 
We may point out in passing that if the original plant 
had been self-pollinated, a much larger proportion of 
the new type might have been expected to appear in 
the next generation. 
In the course of his own experiments, de Vries has 
obtained quite a number of new types of plants by 
methods like the above. It is to be observed that the 
novelty in these cases usually shows a considerable 
range of normal variability of its own, and that its 
first appearance is generally in the form of an extreme 
* “Origin of Species,’ 6th ed., p. 60. 
