254 Xon-Isolable Races. 
in spite of the repeated selection. 1 The curve M has a 
more normal shape than the corresponding curve "1892" 
in Fig. 51; which is obviously due to the fact that the 
former represents a homogeneous group whilst the latter 
is a composite curve embracing all the groups of this 
culture. Curve V is related to curve M as it would be if 
we were dealing with ordinary fluctuating variability ; it 
is simply shifted to one side. 2 
It seems obvious that the race could still be improved 
by sowing the seeds of those seed-parents the apices of 
whose curves are at 11, i. e., that these curves could be 
shifted still further to the right. I have made some such 
sowings since 1892, but only on a small scale and not 
without interruption. They were not intended as a con- 
tinuation of the experiment. The number of petals per 
flower increased slightly, but the type itself was not es- 
sentially altered. I especially never saw a trace of any- 
thing like the origin of a double flower. 
In order to find out whether there was any likelihood 
that the type of my race would in the near future mani- 
fest an improvement I made the following calculation. 
The 295 plants of which the culture of 1892 consisted, 
arose from the seeds of 21 seed-parents. I selected the 
ten best of these parental groups and plotted the curves 
for all the offspring of each seed-parent. The curves 
proved to differ very little from one another. Their 
apices all fell over nine petals, with one exception, which 
was over ten. I should say that in making the calcula- 
tion I have left the groups which contained less than 300 
1 Whereas as a result of the selection of active characters the 
whole curve is shifted; see Vol. T, p. 73, Fig. 18, and the third part 
of the first volume. 
' Sec Vol. T. Fig. 116. on page 536. 
