6 The Significance of Horticultural Varieties. 
short and lack precision being much inferior in this re- 
spect to the accurate accounts that are given of artificial 
crossings. I shall bring together the most important 
facts that I have been able to find, in the following sec- 
tion (2). 
In order to penetrate more deeply into these phenom- 
ena I have endeavored to apply this method to a series 
of cases. With the help of control experiments, and by 
keeping detailed records, I succeeded in finding out how 
such novelties usually develop themselves. Just as hap- 
pens in practice, I was successful with some cases but not 
with others. And the correspondence between my results 
and the experience of breeders seems to me to be so com- 
plete that my experiments may simply be taken as in- 
stances of the method under discussion. 
I propose to distinguish, therefore, between highly 
variable and only slightly variable novelties. The lat- 
*ter are generally assumed to be instances of single var- 
iations which arise suddenly. In the case of these I 
shall, therefore, only have to discuss their origin and the 
question of their constancy. (Chapter IV of this Part.) 
Much more important from the critical standpoint are the 
varieties with a high degree of fluctuating variability, i. e., 
those very cases which passed for instances of the origin 
of new characters by artificial selection (Chapters II and 
VIII). As examples of this I refer to variegated leaves 
and to double and striped flowers. 
If we now compare, from a theoretical standpoint, 
this high variability with the normal examples which we 
dealt with before (Vol. I, pp. 47-52 etc.) we shall see 
that the two are not exactly the same. In variegated 
leaves the yellow alternates with the green, in semi-double 
flowers the petaloid stamens alternate with normal ones 
