organic kingdom.


F. FLUCTUATIONS.

XXV. General laws of fluctuations. 715
Fluctuating variability. Quetelet's law. Individual and partial
fluctuations. Linear variability. Influence of nutrition.
Periodicity curves.

XXVI. Asexual multiplication of extremes. 742
Selection between species and intra-specific selection.
Excluding individual [xvii] embryonic variability. Sugar-canes.
Flowering cannas. Double lilacs. Other instances. Burbank's method
of selection.

XXVII. Inconstancy of improved races 770
Larger variability in the case of propagation by seed,
progression and regression after a single selection, and after
repeated selections. Selection experiments with corn. Advantages
and effect of repeated selection.

XXVIII. Artificial and natural selection. 798
Conclusions. Specific and intra-specific selection. Natural
selection in the field. Acclimatization. Improvement-selection of
sugar-beets by various methods. Rye. Hereditary percentage and
centgener power as marks by which intraspecific selection may be
guided.

Index 827