VIII. NUTRITION AND SELECTION OF SEMI- 
LATENT CHARACTERS. 
26. INCREASED NUTRITION FAVORS THE DEVELOP- 
MENT OF THE ANOMALY. 
Fluctuating variability is a phenomenon of nutrition, 
whereas mutability is the result of hitherto unknown 
causes (Vol. I, p. 575). This statement, which is per- 
haps the sharpest expression of the contrast between 
fluctuating or continuous variability on the one hand 
and occasional sudden transitions from one species into 
another on the other, has been discussed more than once 
in this work. It is equally true for the variability of 
semi-latent characters as for that of normal ones. This 
side of the statement has also been already alluded to, 
and I have cited many instances in order to prove its 
truth. Everywhere nutrition and variability are so in- 
timately connected that the physiology of the latter phe- 
nomenon can hardly be dealt with without discussing 
its relation to the former. 
Artificial selection is the choice of the better nour- 
ished individuals, except of course, when selection is 
carried out in the negative direction (Vol. I, p. 142). 
In the first volume I cited as a proof of this generaliza- 
tion an experiment with a semi-latent character. The 
number of accessory carpels of Papaver somniferum 
pol\ccphahun was shown to be dependent on selection 
